10- MICROBES IN HUMAN WELFARE 

CHAPTER NO.10 MICROBES IN HUMAN WELFARE

 

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            INTRODUCTION

What are microbes?

Microbes are those living organisms which are microscopic. These occur in almost all parts of world. These have been found in all parts of biosphere including air, water and soil.

You would be surprised to know that we use microbe derived products every day.

MICROBES IN HOUSEHOLD PRODUCTS

 

1. PRODUCTION OF CURD, YOGHURT AND BUTTERMILK:

A) Curd. It is produced by the bacterial fermentation of milk. Bacteria involved

in curd formation are Lactic acid bacteria (LAB) which include Lactobacillus

acidophilus, L. lactis and Streptococcus lactis. These bacterial strains

produce lactic acid which coagulate and partially digest the milk proteins at

less than 40° C temperature. A small amount of curd called inoculum is added to milk and contains millions of LAB, which initiates curdling of milk.LAB also synthesizes and releases vitamin Bi2 in the curd which increases its nutritional value. During curdling of milk, Lactobacillus converts lactose to lactic acid and Streptococcus coagulates casein. LAB is also present in our

stomach and help in checking pathogenic microbes.

 

B)Yoghurt :- It is produced by curdling of milk with the help of Streptococcus thermophilus and Lactobacillus bulgaricus at about 40°to 60°C. It is often sweetened and flavoured with fruits.

 

C) Buttermilk:- It is acidulated product which is produced by inoculating skimmed milk with an inoculum of bacteria like Streptococcus lactis and Leuconostoc citrovorum at about 22 degree®

 

2. PRODUCTION OF CHEESE-:- It is nutritive product produced by curdling and ripening of milk. Curdling is done by bacterial strains like Streptococcus lactis and Leuconostoc citrovorum while ripening of solid curd is done by different bacterial strains which provide characteristics texture, flavor and taste to cheese.Depending upon the ripening process there are about 400 types of cheese e.g.

 

Swiss cheese is ripened by bacterium Propionibacterium sharmanii which

produces CO.which causes big holes in cheese.

 

Roquefort cheese is ripened by a specific fungal species Penicillium roqueforti which provides specific flavour to it.

 

3. DOSA AND IDLI :-These are produced by the anaerobic bacterial fermentation of rice during which CO, is evolved and causes

doughing of the raw material

 

4. BREAD (Baking industry):- Bread is prepared by adding Baker's yeast

(Saccharomyces cerevisiae) to the wheat flour. Yeast secretes zymase Complex

which contains several enzymes like

a)Amylase which hydrolysis starch to maltose

b) Maltase which changes maltose to glucose

c)Zymase which converts glucose to ethanol and

 

COs: tries to escape so causing doughing of wheat flour called leavened floor

and is then baked. CO. escapes and makes the bread soft and porous.

 

PART-A VERY SHORT ANSWER TYPE QUESTIONS

A) Multiple Choice Questions:

 

1. The vitamin whose content increases following the conversion of milk into curd by lactic acid bacteria is:

(a) Vitamin C

(b) Vitamin D

(c) Vitamin Bi2

(d) Vitamin E

 

 

2.Big holes in swiss cheese are made by a:

(a) A machine

(b) A bacterium that produces methane gas

(c) A bacterium producing a large amount of carbon dioxide

(d)A fungus that releases a lot of gases during its metabolic activities

 

3.Yeast is used in the production of:

(a)Citric acid and lactic acid

(b)Lipase and pectinase

(c) Bread and beer

(d) Cheese and butter

 

4.The scientific name of Baker’s yeast is:

(a)Saccharomyces

(b)Aspergillus niger

(c) Streptococcus

(d) Lactobacillus

 

5.Microbe responsible for converting milk into curd is:

(a)Penicillium

(b)Aspergillus

(c)Saccharomyces

(d)Lactobacillus

 

B) Fill in the blanks:

1.Lactobacillus converts lactose to ......0....0..

2.Swiss cheese is ripened by bacterium..................

 

C) True/False:

1. Bread is prepared by adding Baker's yeast.

2. Swiss cheese is ripened by a specific fungal species.

3.LAB also synthesizes and releases vitamin B12 in curd.

 

ANSWER KEY: PART -A

A) Multiple choice questions:

 

1 (c) (LAB synthesises and releases vitamin B,2 in curd)

 

2 (c) (Propionibacterium sharmanii produces CO. which causes big holes in cheese)

 

3 (c) (Bread and beer are produced due to fermentation done by yeast Saccharomyces cerevisiae )

 

4 (a) Saccharomyces

 

5 (d) (LAB converts milk into curd)

 

 

B) Fill in the blanks:

1. Lactic acid.

2. Propionibacterium sharmanii

 

C) True/False

1. True

2. False (Swiss cheese is prepared by bacterium Propionibacterium sharmanii )

3. True

 

PART -B SHORT ANSWER TYPE QUESTIONS

1. What are microbes?

2. Give method of preparation of curd.

3. What is zymase?

 

PART -C LONG ANSWER TYPE QUESTION

1. Give an account of use of microbes in household food products

 

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A large number of microbes play important role in producing a number of valuable

products for human welfare. Basic mechanism involved is of fermentation which

involves anaerobic degradation of organic compounds.Fermentative activity of microbes is used industrially to obtain number of products.

 

For any new industrial utilisation of microbial activity, the technology passes

through three stages — Laboratory scale, Pilot plant scale and manufacturing unit.

The development from Laboratory scale to manufacturing unit is called sealing up.

 

Industrial production requires the formation of large quantities of the produce which

generally involves the microbial reactions to proceed in specialized vessel called

Fermentor or Bioreactor.

 

Louis Pasteur found for the first time that beer and buttermilk are produced due to

activity of Yeast and Yeast- like microorganisms. Yeast species used in alcoholic fermentation are Saccharomyces cerevisiae.

 

Alcoholic fermentation is a complex biochemical process during which yeasts

convert sugars to ethanol, carbon dioxide, and other metabolic byproducts that contribute to the chemical composition and sensorial properties of the fermented foodstuffs. Alcoholic fermentation is the basis for the manufacturing of alcoholic beverages such as wine and beer.

 

Type of alcoholic drink obtained and the percentage of alcohol present in them

varies and depends upon the type of raw material used for the fermentation and

the type processing. These alcoholic drinks may be

 

To speed up the malting process in brewing industry, the growth hormone

 Gibberllic acid is added.

 

Distilling is essentially the process whereby a liquid made of two or more parts is

separated into smaller parts of desired purity by the addition and subtraction of

heat from the mixture. The vapours/iquids distilled will separate other ingredients

that have lower boiling points. Distilled spirits are produced from agricultural raw

materials such as grapes, other fruit, sugarcane, molasses, potatoes, cereals, etc.

 

1. Which of the following processes is not involved in the industrial utilisation of microbes?

a. Laboratory scale process

b. Demagnetisation

c. Manufacturing process

d. Pilot plant

 

2. Which of the following is the container where fermentation is carried out?

a. Sludge Eliminator

b. Bioreactor

c. Activator

d. Fermenter

 

3. Who found out that Beer and buttermilk are produced due to the activity of yeast and yeast like organisms?

a. Louis Pasteur

b. Waksman

c. Babes

d. Joubert

 

4. What is the common name of Saccharomyces cerevisiae?

a. Brewer's yeast

b. Wine yeast

c. Sake yeast

d. Ale yeast

 

5. What is the nutrient medium beer?

a. Barley malt

b. Fermented cereals

c. Fermented molasses

d. Fermented juices

 

 

1. The alcohol content in beer is .

2. and are the by- products of fermentation.

3. , and are produced by the

distillation of the fermented broth.

 

1. The crushed food for obtaining malt is called wort.

2. Saccharomyces cerevisiae is also called as Wine yeast.

 

 

1. (b) Industrial utilisation of bacteria and other microbes involve three processes — Laboratory scale process, pilot plant scale and manufacturing unit.

 

2. (b) The container where fermentation is carried out is called a bioreactor. It has an aeration system, pH correctors and temperature adjustors. Bioreactors are often large.

 

3. (a) Louis Pasteur found for the first time that beer and buttermilk are produced due to the activity of yeast and yeast - like organisms.

 

4. (a) Brewer's yeast is the other name for Saccharomyces cerevisiae.

 

5. (a) Barley malt is processed to produce beer.

 

1. 3-6%

2. CQO, and ethanol

3. Whisky, Rum and Vodka.

 

 

1. False. The crushed food mixed with hot water for obtaining malt is called malt. The sweetened nutrient medium before alcoholic

fermentation is called wort.

2. False. Saccharomyces cerevisiae is called as Brewer's yeast.

 

PART B: SHORT ANSWER TYPE QUESTIONS

1. Whyis distillation required for producing certain alcoholic drinks?

2. | To speed up the malting process in brewing industry, which growth hormone is added?

 

PART C: LONG ANSWER TYPE QUESTIONS

1. Discuss various steps involved in the process of Alcohol Formation. (Distilling

Process).

 

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            INTRODUCTION

MICROBES: Microbes are small organisms which are not visible to naked eye because they have a size of 0.1 mm or less. Microbes are present everywhere inside soil, in all types of waters, in air, on dust particles, inside

and outside our bodies as well as other animals and plants.

 

Microbes in biogas production:

BIOGAS: The gas produced by action of bacteria on biomass is called biogas or gobar gas.

 

Composition:Biogas is the mixture of following gases

Methane 50-70%

 

Carbon dioxide 25 - 35%

 

Hydrogen sulphide 1-5 %

 

Hydrogen.

 

MICROBES INVOLVED:A special category of bacteria called Methanogens, are most commonly involved in the production of biogas. These are obligatory anaerobes and

cause anaerobic decomposition of cellulosic materials presently abundantly in the dung of animals to produce biogas. As cattle dung is abundantly available in rural areas so the gobar gas plants are more common in rural

areas. Most common methanogens are Methanobacterium and Methanococcus.

 

BIOGAS PLANT: A biogas plant consists of concrete tank (10 to 15 feet deep). A slurry of animal dung and water is put into the plant. The biogas produced is drawn

through pipes and supplied to the consumers. In order to get a continuous supply of biogas, the plant needs to be regularly fed with waste biomass.Human excreta can also be added to this.Two common types of biogas plants used in our country are:

 

1. FIXED DOME TYPE BIOGAS PLANT:

2. FLOATING GAS HOLDER TYPE BIOGAS PLANT: in which a floating gasholder is placed over the slurry. It moves upward as biogas is

produced in the tank.

 

1. Biogas can be burnt in gas stoves to provide heat.

2. Biogas can be used for cooking, street light and driving engines, so is solution of energy crisis.

3. Biogas burns without smoke and produces a large amount of heat so helps in controlling air pollution.

4. The slurry left in the plant after the gas is withdrawn, is rich in nitrogenous and phosphorus compounds and forms a good manure.

 

LET US KNOW WHAT WE HAVE LEARNT!!!:

PART-A VERY SHORT ANSWER TYPE QUESTIONS:

A) MULTIPLE CHOICE QUESTIONS:

 

1. Which of the following gas is produced by using dung of cattle:

a) Greenhouse gas

b) Nitrous gas

c) Gobar gas

d) Water gas

 

2. Which of the following gases not included in biogas:

a) CH,

b) HS

c) CO,

d) H,O

 

 

3. What do we collectively call the biogas producing bacteria?

a) Archaebacteria

b) Cyanobacteria

c) Eubacteria

d) Methanogens.

 

4. Amajor component of biogas is:

a) Ammonia

b) Methane

c) Ethane

d) Butane.

 

5. The residue left after methane production from cattle dung is:

a) Burnt

b) Burnt in landfills

c) Used as manure

d) Used in civil construction.

 

B) TRUE/FALSE:

1. Biogas plants are more often built in urban area.

2. Biogas plants provide energy source as well as manure.

 

C) FILL UPs:

1. Two main constituents of biogas are and .

2. Biogas is produced during anaerobic fermentation of material.

3. Most common methanogens are and .

 

A) MULTIPLE CHOICE QUESTIONS:

1. (c) Gobar gas.

2. (d) H,O

3. (c) Methanogen

4. (b) Methane.

5. (c) Used as manure.

 

B) TRUE/FALSE:

1. False: Biogas plants are more often built in village area.

2. True.

 

C) FILL UPs:

1. CH,,CO,

2. Cellulosic

3.Methanobacterium, Methanococcus.

 

PART-B SHORT ANSWER TYPE QUESTIONS:

1. Write the composition of biogas.

2. Name the different types of biogas plants used in our country.

3. What are the advantages of biogas plant?

 

PART-C LONG ANSWER TYPE QUESTIONS:

1. What is biogas? Discuss its production in a gobar gas plant.

 

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             INTRODUCTION

Microbes are present everywhere — in soil, water, air. They cause diseases in human

beings, animals and plants. But several microbes are useful to man in diverse ways.

In industry, microbes are used to synthesize a number of products valuable to human beings. Today we are going to read about the industrial production of vitamins and organic acids by microbes.

 

MICROBES IN INDUSTRIAL PRODUCTION OF VITAMINS

Microbes are used for industrial production of the following vitamins: -

 

1. RIBOFLAVIN:-The first commercial microbiological production of riboflavin using bacteria was performed with Clostridium acetobutylicum by acetone-butanol fermentation, where riboflavin was formed as a by product.The fermentative production of riboflavin is naturally carried out by the

wild type flavinogenic ascomycetes, such as Eremothecium ashbyi and Ashbya gossypii, with the accumulation of riboflavin in mycelia at the end of the growth phase, which provides the fungi with a bright yellow colour. Using genetic techniques and supplement optimization, A gossypiistrains could yield as high as 13.7 g/L of riboflavin.

 

 

2. VITAMIN E

The fermentative production of Vitamin E is done from glucose. The microbe used inindustrial production of VitaminE ismicroalgae Euglena gracilis.

 

3. VITAMIN K2

Our most important dietary sources of vitamin K2 are fermented foods like cheese and natto (fermented soybean). Fermentation of soybean by the bacterium Bacillus subtis var natto yield very high amounts of Ko.

 

4. BIOTIN

Escherichia strains are known as  microorganisms which can be used for fermentative production of biotin. Production of biotin and biotin vitamers varied considerably from strain to strain even within a species.

 

5. VITAMIN C

D-sorbitol is converted to L-ascorbic acid using a fermentation step.Today, a two-step fermentation process is widely used by Chinese manufacturers for vitamin C production due to lowcost and high product

quality.

 

6. VITAMIN B12

Vitamin Bi2 is commercially produced by fermentation. It was first obtained

as a byproduct of Streptomyces fermentation in the production of certain antibiotics (streptomycin, chloramphenicol, or neomycin). But the yield was very low. Later, high-yielding strains were developed. And at present,vitamin B12 is entirely produced by fermentation.The bulk production of vitamin B12 is mostly done by submerged bacterial

fermentation with beet molasses medium supplemented with cobalt Chloride.

 

MICROBES IN INDUSTRIAL PRODUCTION OF ORGANIC ACIDS

 

1. LACTIC ACID

Lactic acid is an organic compound produced via fermentation by different microorganisms that can use different carbohydrate sources.

Lactic acid bacteria are the main bacteria used to produce lactic acid and among these, Lactobacillus sp. have been showing interesting fermentation capacities.

 

2. CITRIC ACID

Citric Acid is produced mainly by submerged fermentation using Aspergillus niger or Candida sp. from different sources of carbohydrates,such as molasses and starch-based media. However, other fermentation

techniques, e.g., solid state fermentation and surface fermentation, and alternative sources of carbon such as agro-industrial residues have been intensively studied showing great perspective to its production.

 

3. ACETIC ACID

Acetic acid (CH3COOH) is also called as vinegar. Vinegar fermentation is

one ofthe oldestfermentations knowntoman. Itis formed naturally due to spoilage of wine. Therefore, literally vinegar means “sour wine.”Technically vinegar is fermented food product consisting of about 4 g of

acetic acid per 100 ml. Vinegar was produced only for local consumption until the Middle Ages.

  

4. BUTYRIC ACID

Butyric Acid production from renewable, low-cost biomass in fermentation has attracted large attention in recent years. In this study,the feasibility of corn husk, an abundant agricultural residue, for butyric

acid production by using Clostridium tyrobutyricum immobilized in a

fibrous bed bioreactor (FBB) was evaluated.

 

LET US KNOW WHAT WE HAVE LEARNT!!!!

PART A: VERY SHORT ANSWER TYPE QUESTIONS:

A) MULTIPLE TYPE QUESTIONS: -

 

1. Microbes are present in:

a) air

b) soil

c) water

d) all of these

 

2. Which microbe is used in the production of riboflavin?

a) bacteria

b) algae

c) fungi

d) virus

 

 

 

3. The vitamin whose content increases following the conversion of milk into curd by lactic acid bacteria is:

a) Vitamin C

b) Vitamin D

c) Vitamin B12

d) Vitamin E

 

4. The fermentative production of Vitamin E is done from:

a) lactic acid

b) glucose

c) citric acid

d) fat

 

5. Acetic acid (CH3COOH) is also called as:

a) vinegar

b) hydroxy propanoic acid

c) hydrochloric acid

d) ascorbic acid

 

B)FILL IN THE  BLANKS:

1. The microbe used in industrial production of is microalgae Euglena gracilis.

2. Fermentation is one of the oldest fermentations known to man.

3. The bulk production of is mostly done by submerged bacterial fermentation with beet molasses medium supplemented with

cobalt chloride.

 

C) TRUE/FALSE:

1. Citric Acid is produced mainly by submerged fermentation using

Aspergillus niger or Candida sp.

2. Butyric acid is formed naturally due to spoilage of wine.

 

PART A: ANSWER KEY

A) MULTIPLE TYPE QUESTIONS: -

 

1. d): all of these

2. c): fungi

3. c): vitamin B12

4. b): glucose

5. a): vinegar

 

B)FILL IN THE  BLANKS:

1. Vitamin E

2. Vinegar Fermentation

3. Vitamin Biz

 

C) TRUE/FALSE:

1. True

2. False: Acetic acid is formed naturally due to spoilage of wine.

 

PART B: SHORT ANSWER TYPE QUESTIONS:

1. Write the industrial production of Vitamin E.

2. What is chemical formula of Acetic acid and what is the common name for it?

3. How was Vitamin Bu: first produced as?

 

PART C: LONG ANSWER TYPE QUESTIONS:

1. Give a brief explanation about the industrial production oforganic acids

by microbes.

 

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INTRODUCTION:

Traditional agricultural practices are not sufficient to fulfill increasing food

demands of increasing human population so Single Cell Protein is an alternative source of producing protein rich microbial biomass by unicellular or multi-cellular micro-organisms for human and animal consumption.

 

SINGLE CELL PROTEIN:-Single Cell Protein is Microbial biomass produced by unicellular and multi-cellular micro-organisms and can be

used as food or feed additives.

 

SCP is a protein rich biomass.

 

Protein content is 45 to 55% and even more in some cases.Protein contents of SCP of certain micro-organism

 

PRODUCTION OF SCP: - Process of production of SCP involves following steps:-

 

(a) Preparation of suitable medium with suitable carbon source (e.g. Methanol

for Methylophilus bacterium, Sulphite liquor for Paecilomyces COz for Chlorella & Spirulina.

 

(b) Addition of certain salts and gaseous ammonia to carbon source to promote

the growth of micro-organisms.

 

(c) Inoculation of Pure strain of selected micro-organism.

 

(d) Proper aeration & cooling of the medium.

 

(e) The SCP is collected from the medium by a variety of methods like filtration

or centrifugation.

 

ADVANTAGES OF SCP:

a) SCP is rich in protein but poor in fats.

b) SCP can be produced throughout the year.

c) Huge quantities of SCP can be produced from small area due to rapid growth of microbes.

d) Substrates used are cheaper e.g. Spirulina is grown on waste water from potato processing plant s which has high amount of starch.

 

DISADVANTAGES OF SCP:

(a) Some microbes are harmful for human and animals as they can produce toxin in their biomass.

(b) Microbial biomass may lead to allergic reactions and indigestion.

(c) Higher nucleic acid content in SCP may lead to kidney stone.

(d) Production SCP is very expensive.

 

APPLICATIONS OF SCP:

(a) SCP used as food source for example in soup, as vitamin carriers, in ready to serve food items etc.

(b) Have medicinal uses.

(c) Used in paper industry, leather  processing and foam stabilizer.

(d) Used in poultry industry and animal feed industry.

 

LET US SEE WHAT WE HAVE LEARNT!!!

PART: A VERY SHORT ANSWER TYPE QUESTIONS:

A) MCQs:

 

1.Single cell protein is?

a) Protein synthesised by muscle cells

b) Protein synthesised by skin cells

c) Protein synthesised by microorganisms

d) Protein synthesised by liver cells.

 

 

2.SCP is rich in which of the following amino acids

a) Histidine and valine

b) Histidine and glycine

c) Proline and leucine

d) Lycine and methionine

 

3.Methanol is used as carbon source for:

a) Methylophilus Bacterium

b) Spirulina

c) Chlorella

d) Paecilomyces

 

4.What of the following is most common sources of SCP?

a) Unicellular algae

b) Unicellular bacteria

c) multicellular yeast

d)Single celled yeast

 

5. Which of the following is not organic matter on which microorganism

are raised for SCP?

a) Sawdust

b) paddy straw

c) Acid

d) whey

 

B) FILL UPs:

1. can be grown on waste water from potato processing plant.

2.Sugar__is important substrate for yeast .

3. SCP environmental pollution.

 

C) TRUE /FALSE:

1. 250gm of micro-organism like ethylophillus methylotrophus can produce 25 tonnes of protein.

2. Shift from grain to meat diets creates more demand for cereals.

 

ANSWER KEY: PART -A

A. Multiple choice questions:

 

1.(c) SCPs are Protein produced by micro-organism like algae,fungi and bacteria etc.

 

2.(d) SCPs rich in amnio-acids lysine and methionine.

 

3.(a) Methanol is used as carbon source for Methylophilus bacterium

 

4.(d) Single celled yeast for e.g Candida utilis is most common source of SCP.

 

5.(c) Microbial biomass can be raised using organic matter like sawdust, paddy straw and whey.

 

B. Fill Ups:

1. Spirulina

2. Molasses

3. Reduces

 

C. True/False:

1. True: Because of high rate of biomass production and growth 250gm of Methylophilus can produce 25 tons protein.

2. True: As it takes 3 to 10 kg of grain to produce 1 kg of meat by animal farming.

 

PART: B SHORT ANSWER TYPE QUESTIONS

1. What is SCP?

2. Name steps involved in production of SCP.

3. What is the economic value of Spirulina?

 

PART: C LONG ANSWER TYPE QUESTION

1. Discuss advantages, disadvantages and applications of SCP?

 

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            INTRODUCTION

MICROBES IN SEWAGE TREATMENT:Municipal waste water which contains large amounts of organic matter is called sewage.Before disposal, hence, sewage is treated in sewage treatment plants (STPs)by the heterotrophic microbes to make it less polluting.

 

Sewage treatment is carried out in two stages: -PRIMARY TREATMENT OR PHYSICAL TREATMENT: -

 

These treatment steps basically involve physical removal of large and small particles.

 

Initially, floating debris is removed by sequential filtration and then the

grit are removed by sedimentation.

 

All solids that settle form the primary sludge, and the supernatant forms the effluent.

 

The effluent from the primary settling tank is taken for secondary treatment.

 

SECONDARY TREATMENT OR BIOLOGICAL TREATMENT:

 

The primary effluent is passed into large aeration tanks where it is constantly agitated which allow vigorous growth of useful aerobic microbes into flocs.

 

Flocs are the masses of bacteria associated with fungal filaments to form mesh like structures.

 

While growing, the microbes significantly reduce the BOD (biochemical oxygen demand) which is the amount of oxygen required to oxidise total organic matter in the effluent.

 

The BOD test measures the rate of uptake of oxygen by micro-organisms; the greater the BOD of waste water, more is its polluting

potential.

 

The effluent is then passed into a settling tank where the bacterial ‘flocs’ are allowed to sediment and the sediment is called activated sludge.

 

A small part of the activated sludge is pumped back into the aeration tank to serve as the inoculum.

 

The remaining major part of the sludge is pumped into large tanks called anaerobic sludge digesters where other kinds of bacteria grow anaerobically which digest the bacteria and the fungi in the sludge.

 

During digestion, bacteria produce a mixture of gases such as Methane, Hydrogen Sulphide and Carbon Dioxide which form Biogas.

The effluent from the secondary treatment plant is generally released into

natural water bodies like rivers and streams.

The Ministry of Environment & Forests initiated Ganga Action Plan & Yamuna Action Plan to save from water pollution.

 

PART: A VERY SHORT ANSWER TYPE QUESTIONS:

A) MCQs:

 

1. Wastewater treatment generates a large quantity of sludge, which can be

treated by:

(a) anaerobic digesters

(b) flocs

(c) chemicals

(d) oxidation pond

 

2. BOD of wastewater is estimated by measuring the amount of

(a) total organic matter

(b) biodegradable organic matter

(c) oxygen evolution

(d) oxygen consumption

 

3. In the sewage treatment, bacterial flocs are allowed to sediment in a settling tank. This sediment is called as:

(a) inactivated sludge

(b) activated sludge

(c) primary sludge

(d) secondary sludge

 

 

 

4. The masses of bacteria held together by slime and fungal filaments to form mesh-like structures are called as:

(a) primary sludge

(b) flocs

(c) activated sludge

(d) anaerobic sludge

 

5. Process of biogas production is:

(a) aerobic process

(b) anaerobic process

(c) active process

(d) passive process

 

B) TRUE / FALSE:

1. Secondary treatment of sewage waste is also known as biological treatment.

2. The lower the BOD of waste water, more is it's polluting potential.

3. Untreated Sewage if released in rivers causes pollution.

 

C) FILL IN THE BLANKS:

1. Sewage is treated in sewage treatment plants by the .

2. is a mixture of gases such as methane, hydrogen sulphide and carbon dioxide.

 

A) MCQs:

Ans. 1: (a) anaerobic digesters In anaerobic digesters, bacteria grow anaerobically which digest the bacteria and the fungi present in the sludge

.

Ans. 2: (d) oxygen consumption BOD is the amount of oxygen required to oxidise total organic matter in the effluent. So, BOD is estimated by measuring the amount of oxygen consumed.

 

Ans. 3: (b) activated sludge Bacterial flocs are allowed to sediment in a settling tank known as activated sludge.

 

Ans. 4: (b) flocs

Flocs are the masses of bacteria associated with fungal filaments to form mesh like

structures.

 

Ans. 5: (b) anaerobic process

Biogas is produced by the decomposition of organic matter in the absence of oxygen. So, production of biogas is an anaerobic process.

 

B) TRUE / FALSE:

1. True

2. False (Greater the BOD of waste water, more is its polluting potential).

3. True

 

C) FILL IN THE BLANKS:

1. heterotrophic microbes

2. Biogas

 

PART: B SHORT ANSWER TYPE QUESTIONS:

1. What is sewage? In which way can sewage be harmful to us?

2. What is the key difference between primary and secondary sewage treatment?

3. Why is secondary sewage water treatment referred to as biological treatment?

 

PART C: LONG ANSWER TYPE QUESTIONS:

1. Explain the different steps involved in sewage treatment before it can be released into natural water bodies.

 

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INTRODUCTION

A microorganism or microbe is an organism which is too small to be seen by the

unaided human eye. They are microscopic and can be seen only with the help of

microscope.

 

“Microorganisms present everywhere, e.g. geysers (thermal vents), under snow,

deep in soil etc.”

 

Microbes are diverse: protozoa, bacteria, fungi and microscopic plant viruses,

viroids and prions.

 

Microbes cause a large number of diseases in human beings, animals and plants.

But all microbes are not harmful; several microbes are useful to human beings in

diverse ways. Today we will discuss about role of microorganisms in production of

Antibiotics and Enzymes.

 

ANTIBIOTICS: The discovery of antibiotics is chance observation of Alexander Fleming that growth of fungus, Penicilium notatum, killed

bacteria, Staphylococcus aureus.

 

Antibiotics means “Against Life”.

Antibiotics are chemical substances, which are produced by some microbes and

can kill or retard the growth of other (disease-causing) microbes without harming

the host.Penicillin produced by Alexander Fleming from Penicillium notatum.

 

While working with staphylococci, Earnest chain and Howard Plorey awarded

Nobel Prize in 1945 for establishing Penicillin as an effective antibiotic.

“Antibiotics -- treat deadly diseases --- such as plague, whooping cough, diphtheria

and leprosy etc.Antibiotics are secondary metabolites used as drugs. The term was coined by Waksman in 1942.

 

In later industrial production of Penicilin, the Penicilium notatum was replaced by

Penicillium chrysogenum. Waksman also discovered most important antibiotic;

Streptomycin. Now more than 7000 antibiotics are known. Antibiotics act on different metabolic pathways. A broad spectrum antibiotic destroys a number of

pathogens while specific antibiotic is useful against only one pathogen.

 

PRODUCTION OF ANTIBIOTICS:Maximum antibiotics (70%) are obtained from Bacillus. Antibiotics are extracted from Lichens, Fungi, Actinomycetes, and Eubacteria.Antibiotic production can be grouped into three methods:

Natural Fermentation, Semi-Synthetic, and Synthetic.As more and more bacteria continue to develop resistance to currently produced

antibiotics, research and development of new antibiotics continues to be important. In addition to research and development into the production of new antibiotics, repackaging delivery systems is important to improving

efficacy of the antibiotics that are currently produced. Improvements to this

field have seen the ability to add antibiotics directly into implanted devices,

aerosolization of antibiotics for direct delivery, and combination of antibiotics with non-antibiotics to improve outcomes. The increase of antibiotic resistant strains of pathogenic bacteria has led to an increased urgency for the funding of research and development of antibiotics and a desire for

production of new and better acting antibiotics.

 

INDUSTRIAL PRODUCTION TECHNIQUES

FERMENTATION:Industrial microbiology can be used to produce antibiotics via the process

of FERMENTATION, where the source microorganism free from any contamination, is grown in large sterilized containers, the BIOREACTORS (100,000-150,000 litres or more) containing a liquid growth medium. Oxygen

concentration, temperature, pH and nutrients are closely controlled. As antibiotics are secondary metabolites, the population size must be controlled very carefully to ensure that maximum yield is obtained before the cells die.Once the process is complete, the antibiotic must be evaluated and then

extracted and purified to a crystalline product. This is easier to achieve if the

antibiotic is soluble in organic solvent. Otherwise it must first be removed by ion

exchange, adsorption or chemical precipitation.

 

SEMI-SYNTHETIC:

A common form of antibiotic production in modern times is semi-synthetic.Semi-synthetic production of antibiotics is a combination of natural fermentation and laboratory work to maximize the antibiotic. Maximization

can occur through efficacy of the drug itself, amount of antibiotics produced, and

potency of the antibiotic being produced.

An example of semi-synthetic production involves the drug ampicillin. A beta

lactam antibiotic just like penicillin, ampicillin was developed by adding an

addition amino group (NHz2) to the R group of penicillin. This additional amino

group gives ampicillin a broader spectrum of use than penicillin.Methicillin is another derivative of penicillin and was discovered in the late 1950s. The key difference between penicillin and methicillin being the

addition of two methoxy groups to the phenyl group. These methoxy groups allow methicillin to be used against penicillinase producing bacteria that would otherwise be resistant to penicillin.

 

SYNTHETIC:

Not all antibiotics are produced by bacteria; some are made completely synthetically in the lab. These include the quinolone class, of which nalidixic acid is often credited as the first to be discovered. Like other antibiotics before it the discovery of nalidixic acid has been chalked up to an accident,discovered when George Lesher was attempting to synthesize chloroquine.

 

ENZYMES:A number of enzymes are produced commercially from microbes for industrial and medical use.

Microbes are also used for commercial and industrial production of certain chemicals like organic acids and alcohols.Aspergillus niger (a fungus) - citric acid Acetobacter aceti (a bacterium) - acetic acid Clostridium butylicum (a bacterium) - butyric acid Lactobacillus (a bacterium) - lactic acid.Yeast (Saccharomyces cerevisiae) — ethanol Monascus purpureus the yeast, produces Statins have been commercialised as blood cholesterol lowering agents.

 

ENZYMES LIPASES enzyme obtained from Fungi (Aspergillus niger, Mucor javanicus

Candida lypolytica, Geotrichum candidum), used in detergent formulations --

helpful in removing oily stains from the laundry.PECTINASES & PROTEASES enzymes obtained from both Bacteria (Bacillus

subtilis & B. licheniformis) and Fungi (Aspergillus oryzae, Penicillium roquifortt)

Pectinases are used to clarify juices, removing bitterness, retting of fibres and

fermentation of coffee. Proteases are used in enhancing tenderness of meat,extracting fish liver oil, clarification of alcoholic drinks, softening of cheese and

 

bread, cleansing of silk, Synthesis of glue and used in detergents to remove the

stains of proteins.STREPTOKINASE enzyme (Streptococcus) -- used as a ‘clot buster’ for removing clots from the blood vessels of patients of heart attack or Myocardial Infarction.AMYLASES; starch digesting enzyme obtained from Aspergillus oryzae, A. niger,

Rhizopus oryzae, Bacillus diastaticus, B. subtilis etc. The enzyme is used in

softening and sweetening of bread, DE sizing fibres, Clearing starch related stains.

LACTASE; enzyme obtained from Fungi; Yeast. Used in preventing crystal formation in milk products.CHYMOSIN (RENNIN); enzyme produced by species of Mucor & Endothia. Used

in preparation of cheese.

 

A) VERY SHORT ANSWER TYPE QUESTIONS:

a) MCQs:

 

1. Roquefort cheese is ripened by using:

a. Yeast

b. Bacterium

c. Fungus

d. Cyanobacterium

 

2. Which antibiotic is NOT correctly matched?

a. Penicillin --- Penicillium chrysogenum

b. Bacitracin --- Bacillus licheniformis

c. Streptomycin— Bacillus griseus

d. Tetracycline— Streptomyces taxas

 

3. Streptokinase is used in:

a. Removal of oil stains

b. Lowering of blood cholesterol

c. Immuno suppressive agent

d. Removal of clots from blood vessels

 

4. Name the scientist credited for using Penicillin as antibiotic.

a. Alexander Fleming

b. Chain & Florey

c. Waksman

d. Louis Pasteur

 

5. Baker's Yeast is:

a. Saccharomyces cerevisiae

b. Saccharomyces octosporous

c. Saccharomyces ludwingli

d. Shizosaccharomyces

 

b) TRUE/FALSE:

1. Antifungal bacterial antibiotic is Polymixin.

2. Erythromycin is obtained from Streptomyces venezuelae.

 

c) FILL UPs:

1. Dish washer powder contains an enzyme.................

2. .............prevents crystal formation in milk products.

3. The discovery of ..............is chance observation of Alexander

Fleming.

 

ANSWER KEY: PART -A

a) MCQs:

 

1. (c) Fungus; Penicillium roquiforti

 

2. (c) Bacillus griseus The correct one is Streptomyces griseus.

 

3. (d) Streptokinase is an enzyme used for removal of clots from

blood vessels.

 

4. (b) Chain & Florey. Alexnder Fleming discovered Penicillin.Waksman coined the term Antibiotics. Louis Pasteur is known for

Vaccination.

 

5. (a) Saccharomyces cerevisiae

 

b) TRUE/FALSE:

1. True

2. False: Erythromycin is obtained from Streptomyces erythreus.

 

c) FILL UPs:

1. Amylase

2. Lactase

3. Antibiotics

 

B) SHORT ANSWER TYPE QUESTIONS:

1. Name two antibiotics, their source and function.

2. Name the enzyme produced by streptococcus bacterium. Explain its importance in medical science.

 

C) LONG ANSWER TYPE QUESTIONS:

1. How are antibiotics discovered? Give the role and source of any four antibiotics.

2. Describe important enzymes obtained through microbial activity.

 

A118

 

          INTRODUCTION

BIOCONTROL refers to the use of biological methods for controlling plant diseases and pests.

BIO-CONTROL AGENTS: -Organisms which are used to control harmful organisms and plant pests, other than insects. Microbes are also used as biocontrol agents. These microbes include bacteria, fungi, virus and protozoans.

 

CONVENTIONAL METHODS TO CONTROL PESTS:-Presenitly, the pest control is generally done by the use of chemical pesticides. These chemical pesticides are divided into categories like weedicides (to control unwanted plants called weeds, in the crop fields), insecticides(to kill specific insects),rodenticides(to kill rats, mice etc.)

 

HARMFUL EFFECTS OF CHEMICAL PESTICIDES ARE:-

1) Chemical pesticides are toxic and non- biodegradable, hence pollute the environment.

2) These encourage the development of resistant strains.

3) These kill both useful and harmful organisms indiscriminately.So, there is URGENT NEED OF BIOCONTROL to save our resources and biodiversity.

 

BIO-PESTICIDES are of biological origin and are divided into two categories like Bioherbicides and bioinsecticides.

 

PRINCIPLE OF BIOCONTROL:-Biocontrol is based on Natural Predation .Microbes act as biocontrol agents in three ways, either they cause disease in the pests or compete with them or kill them.

 

EXAMPLES OF MICROBIAL BIOLOGICAL CONTROL ARE:-

Bacillus thuringiensis (a bacterium)

 

Trichoderma (a fungus )

 

Baculovirus (Virus)

 

1) BIOHERBICIDESES

BIOHERBICIDES are living organisms that destroys weeds without harming the crop plants.First bioherbicide was “palmivoralt” obtained from a fungus Phytophthora palmivora in 1981.“Devine” and "Collego" are fungal spores which are sprinkled over weeds to eliminate them.

 

2) BIOINSECTICIDESE These are living organisms or their products which are able to kill or repel specific disease causing insects. These are important component of

Integrated Pest Management (IPM)

 

(a) Lady bird beetle (Coccinella) feeds on aphids

 

(b)Dragon flies are useful to get rid of mosquitoes.LADYBIRD (with red & black marking) DRAGON-FLY

 

(c) TRICHODERMA is a free-living soil fungus that is common inroot ecosystem. It acts as a bio control agent of several plant pathogens.

 

(d) BACULOVIRUSES are pathogenic DNA viruses which infect and kill many insect pests and other arthropod pests.Most important one involved in biological control is Nucleo Polyhedro Virus.(NPV)These viruses are species - specific and have narrow spectrum insecticidal effect, so do not have any negative effect on other  organisms.Baculoviruses are known to control pests like potato beetles, aphids and corn-

borers.

 

(e) Bacillus thuringiensis bacterium is most potent for producing chemicals

with insecticidal properties. This bacterium has a short segment of cry gene which

codes for protein toxin, called thurioside, which when ingested by larvae of different

groups of insects, inhibits the ion transport in midgut and kill them.Bt is available in the market in the form sachets as dried spores which are dissolved in water and sprayed on vulnerable plants such as fruits trees and Brassicas.Using rDNA technology, Scientists have introduced Bt toxin genes (cry)into plants. Such plants are resistant to attack by insects.

 

LET US KNOW WHAT WE HAVE LEARNT!!!

 

1) Which of the following is not a bio-control agent?

a) Baculovirus

b) Trichoderma

c) Spirulina.

d) Bacillus thuringiensis

 

2) IPM stands for:

a) Intermediate pest management

b) Indian pest management

c) Integrated plant management

d) Integrated pest management

 

3) First developed Bio-insecticide:

a) Rotenone

b) Pyrethrin

c) Sporeine

d) Azadirachtin

 

4) A biocontrol agent:

a) acts as a predator

b) Competes with the disease-causing organisms

c) acts as a parasite

d) All of the above

 

5) In Bacillus thuringiensis, gene encoding for toxic protein is:

a) Try

b) Fry

c) Cry

d) Dry

 

1) Biocontrol is based on the principle of Natural predation. (T/ F)

2) When larvae eat bacterial spores, then toxin is released in the gut of the

larvae. (T/F)

 

 

1)..... are UNWanted plants in a crop field.

2) Trichoderma IS a .....ss0s0e+2ee8fUNGuS Common in root ecosystem.

3) First DIO NErbiCiIde WAS.....

 

NCERT PA RT KEY:PART-A

(A) MCQs:1)

(c) Spirulina

2) (d) Integrated pest management

3) (c) Sporeine

4) (d) All of the above

5) (c) Cry

 

(B) True /False:

1) True

2) True

 

(C) Fill — in the blanks :

1) Weeds

2) Free-living

3) Palmivoralt

 

Q1:- Enlist commonly used microbial biocontrol agents.

Q2:- How do chemical pesticides affect human health and environment.

 

Q1:- Microbes can be employed to decrease the use of chemical pesticides.

Explain how this can be accomplished?

 

A119

 

           INTRODUCTION

Organic farming is increasing the production of pollutant-free crops. It involves the use of biofertilizers and biopesticides which

increases the nutrient quality of the crop andcontrols any kind of pest and pathogen.

 

BIOFERTILIZERS: These are microorganisms that add to the nutrient quality of the soil. Bacteria, fungi, and algae are some of the

beneficial microorganisms that help in improving the fertility of soil.

 

CLASSIFICATION OF BIOFERTILIZERS: Biofertilizers are classified as:

 

Free-living nitrogen-fixing bacteria like Azotobacteria, and Rhodospirillum.

 

Free-living Nitrogen-fixing Cyanobacteria like Anabaena,and Nostoc.

 

Loose association of nitrogen-fixing bacteria like Azospirillum.

 

Symbiotic nitrogen-fixing bacteria like Rhizobium, and Frankia.

 

MICROORGANISMS USED AS BIOFERTILIZERS:

1) Rhizobium: They form root nodules in leguminous plants and fix the atmospheric nitrogen into an organic form.Rhizobium also has no negative effect on soil quality and

improves the quality, nutrient content, and growth of the plant.

 

2) Azotobacter: These are free-living nitrogen fixers found in All types of upland crops. These not only fix nitrogen but

but also provide certain antibiotics and growth substances to the plant.

 

3) Azospirillum: Unlike Azotobacter, these can be used in wetland areas. They are found inside the roots of the plant (non-free-living)where they fix the atmospheric nitrogen.

 

4) Blue-Green Algae: These are free-living nitrogen-fixing cyanobacteria that are present only in wet and marshy lands.

However they donot survive in acidic soil

 

         

IMPORTANCE OF BIOFERTILIIZERS:

Biofertilizers are eco-friendly and are not harmful to the environment.

 

These improve the soil quality thereby increasing plant productivity.

 

The farmers can prepare the inoculum of these

microbes and inject them into the plants when

required.

 

They produce growth-promoting substances in the soil.

 

Biofertilizers can be used in semi-arid areas also.

 

Biofertilizers are the perfect alternative to

chemical fertilizers.

 

The chemicals not only harm the soil and its

productivity but also harm the living organisms consuming the crops grown on that soil.

 

They have gained recognition over the years

and are being implemented on a large scale.

 

They increase agricultural productivity

without harming human health.

 

LET US LKNOW WHAT WE HAVE LEARNT!!

MULTIPLE CHOICE QUESTIONS:

 

1) Which of the following is not a biofertilizer?

(a)Nostoc

(b)Azospirillum

(c)Rhizobium

(d)Azotobacter

 

2) Which of the following fern is a biofertilizer?

(a)salvina

(b)Azolla

(c) pteridium

(d)marsilea

 

3) Which of the following is a pair of the biofertilizers?

(a)salmonella &e.coil

(b)rhizobium & grasses

(c)nostoc & legume

(d)Azolla & BGA

 

4) This is not used in organic farming?

(a)snail

(b)earthworm

(c)oscillatoria

(d)Glomus

 

FILL IN THE BLANKS:

1) Legumes fix through bacteria in their roots.

2) The biofertilizers present in the roots of legume is .

3) Green manuring enhances crop yield.

 

TRUE or FALSE: Organic farming does not include chemical fertilizers.

 

PART B: SHORT & LONG ANSWER TYPE QUESTIONS

SHORT ANSWER TYPE

1) What are biofertilizers? Give some examples.

2) What are the classifications of biofertilizers?

 

LONG ANSWER TYPE

1) Describe the different types of microorganisms that can be  used as bio fertilizers?

 

 

MCQ:

1(C)RHIZOBIUM

2(B)AZOLLA

3(D) AZOLLA & BCG

4(A)SNAIL

 

FILLIN BLANKS:

1) nitrogen

2)rhizobium

3)30-50%

 

TRUE FALSE:

TRUE

 

A120

 

RECAPITULATION

 

Microbes or micro-organism is a living organism that can only be seen under a

microscope.Microbes are present everywhere in soil, water, air, inside our body and that of

other animals and plants .They are present even at sites where no other life form exist.

 

Microbes belong to diverse groups of organism e.g. Bacteria, Fungi,Protozoa, Viruses. Viroids, and Prions are also included amongst microbes.

 

Microbes are used to man in diverse ways:

1) Microbes in house hold products

2) Microbes in Industrial products

3) Microbes in Sewage treatment

4) Microbes in production of biogas

5) Microbes as biocontrol agents

6) Microbes as biofertilizers

 

It is clear from the diverse uses that human beings have put microbes to that they

play any important role in the welfare of human society.

 

DEAR STUDENTS NOW LET US DO NCERT QUESTIONS:

Q.1 Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes with help of a microscope,which sample would you carry and why?

Ans. A sample curd can be used to show the presence of bacteria. Numerous (LAB)

lactic acid bacteria are present in curd acid are produced by these bacteria that

coagulate and digest milk proteins.

 

Q.2 Give examples to prove that microbes release gases during metabolism.

Ans. The puffed appearance is seen in dough which is used for making idli and

dosa. This is due to the action of bacteria CO2 (carbon dioxide) is released. This

CO2 released form the dough gets caught within the dough, giving it a puffed

appearance.

 

Q.3 In which food would you find lactic acid bacteria? Mention some of their useful applications.

Ans. Lactic acid bacteria is present in curd.

Their useful application are as follows :-

1) Formation of milk into curd is produce by this bacteria.

2) The content of vitamin B12 increases in the curd.

3) Presence of lactic acid bacteria in the stomach keep a check on the diseases

causing micro-organisms.

 

Q.4_Name some traditional Indian foods made of the wheat, rice and Bengal gram (or their products) which involve use of microbes.

Ans:- 1.) In the making of dosa and idli, rice powder is fermented by bacteria and for

creating bread from wheat, yeast  (Saccharomyces cerevisine) is used.

2.) Microbes are used to ferment fish, soyabean and bamboo shoots to create

foods.

 

Q.5 In which way have microbes played a major role in controlling disease caused by harmful bacteria?

Ans. Several micro-organisms are used for preparing medicines e.g. antibiotics.

Either they get killed or the growth gets stopped by disease causing micro-

organisms.So these antibiotics are then used in controlling disease.

 

Q.6_ Name any two species of fungus, which are used in the production of the antibiotics.

Ans.1.) Penicillium notatum (antibiotics penicillin)

2.) Cephalosporium (antibiotic Cephalosporium)

 

Q.7 What is sewage? In which way can sewage be harmful to us?

Ans. The municipal waste water including both liquid and solid wastes which is carried away in drains.

Harmful effects of sewage:-

1) It can spread water borne diseases.

2) Untreated sewage produces offensive odour.

3) It decreases flora mid fauna of H2O.

 

Q.8 What is the key difference between primary and secondary sewage treatment?

Ans. Removal of large and small particles from the sewage though filtration and the

sedimentation by physical mean is called Primary Sewage Treatment.Secondary Sewage Treatment includes biological digestion of organic matter by microbes. Secondary sewage treatment is very costly and complicated process.

 

Q.9 Do you think microbes can also be used as source of energy? If yes, how?

Ans. Yes, microbes can be used as source of energy. Methanobacterium are used for the production of biogas use of microbial culture for SCP (Single Cell Protein).

 

Q.10 Microbes can be used to decrease the use of chemical fertilizers and pesticides. Explain how this can be accomplished.

Ans. Organisms that enrich the nutrient quality of the soil are the microbes which can be used as bio fertilizers bacteria, fungi and cyanobacteria are the main source of bio fertilizers.

1) A nodule on the roots of leguminous plants that is formed by Rhizobium fixes the atmospheric nitrogen into organic form which is used by the plant as a

nutrient.

2) Symbiotic association of vascular host plant with fungus helps within the absorption of phosphorous from soil and passes it to the plant.

3) Cyanobacteria e.g. Nostoc, Anabaena add organic matter to the soil and increase its fetility.

 

Q.11 Three water sample namely river water, untreated sewage water and

secondary effluent discharged from sewage treatment plant were subjected to BOD test. The sample were labelled A, B and C; but the laboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20mg/L, 8mg/L and 400mg/L, respectively. Which sample of the most polluted?Can you assign the correct label to each assuming the river water is relatively clean?

Ans. Sample A (BOD 20mg/L) is secondary effluent discharged from a sewagw

treatment plant sample B (BOD 8mgj/L) is river water Sample C (BOD 400mg/L) is

the untreated sewage water.As BOD is the direct measure of the organic matter present in water, higher the BOD, the more polluted the water. So sample C is most polluted.

 

Q.12 Find out the name of the microbes form which cyclosporine A (an immunosuppressive drug) and statins (blood cholesterol lowering agents) are obtained.

Ans. 1) Cyclosporine-A is obtained form the fungus trichoderma polysporum.

2) Statins are produced by yeast monascus purpureus.

 

Q.13 Find out the role of microbes in the following and discuss it with your teacher.

(a) Single cell protein (SCP)

(b) Soil

Ans. (a) Single Cell Protein (SCP)

it refers to harmless microbial cells that may be used as an alternate source of

excellent protein just like mushrooms (a fungus) on industrial scale microbes like

spirulina methylophilus, methylotrophus are grown on materials containing starch like

waste, water from potato processing plants, animal manure and even sewage to

obtain single cell protein. Dried cell of pseudomonas grown on petroleum has

69% protein.

 

(b) soil :- The most favorable habitat of microorganisms is soil. The micro-organism

present in soil increases the soil fertility by decomposing organic matter they also fix

atmospheric N2 into usable forms.

 

Q.14 Arrange the following in the decreasing order (most important first) of their importance, for the welfare of human society. Give reasons for your answer.Biogas, citric acid, penicillin and curd

Ans. Penicillin> Biogas> curd > citric acid

1. Penicillin:- Used to cure many bacterial diseases.

2. Biogas:- Important source of energy in sural areas.

3. Curd:- It has excellent nutrient value.

4. Citric acid:- Used as a preservative of food.

 

Q.15 How do bio fertilizers enrich the fertility of the soil?

Ans. Bio fertilizers are living organisms which help in increasing fertility of the soil. It involves selection of beneficial micro-organisms that help in improving plant growth through the supply of plant nutrients many species of bacteria and cyanobacteria

have the ability to fix free atmospheric nitrogen.One of the major advantage with bio fertilizers is, they are ecofriendly and cost

effective.

 

A121

 

             RECAPITULATION

Dear students we have discussed the chapter no.10 “microbes in human welfare” and its NCERT questions in previous daily dose assignments.Now let us revise important concepts of this chapter.

 

MICROBES IN HOUSEHOLD PRODUCTS:

 

1. PRODUCTION OF CURD:Milk is converted to curd by micro-organisms such as Lactobacillus and others commonly called lactic acid bacteria (LAB) which grow in milk and convert it to curd.

 

2. FERMENTATION:

(a)The dough, which is used for making foods such as dosa and idli is also fermented by bacteria. The puffed-up appearance of dough is due to the production of CO2.

 

(b)The dough, which is used for making bread, is fermented using baker's yeast

(Saccharomyces cerevisiae).

 

(c)A number of traditional drinks and foods are also made by fermentation by the

microbes.

 

(d)Toddy, a traditional drink of me parts of southern India is made by fermenting sap from palms.

 

MICROBES IN INDUSTRIAL PRODUCTS:

 

FERMENTED BEVERAGES:Microbes are used for the production of beverages like wine, beer, whiskey, brandy or rum. Saccharomyces cerevisiae, is used for the production of fermented beverages. Malted cereals and fruit juices are fermented by S.cerevisiae to

produce ethanol.

 

MICROBES IN INDUSTRIAL PRODUCTS:

ANTIBIOTICS & ENZYMES:Antibiotics are the chemical substances which are produced by some microbes and can kill or stop the growth the growth of other microbes. Alexander Flemming discovered penicillin obtained from Penicillium notatum which was the first

antibiotic to be discovered. Antibiotics are produced by several groups of microbes

such as bacteria, fungi, and actinomycetes.

Enzymes are biocatalysts that play an important role in metabolic and biochemical

reaction. Microorganisms are the primary source of enzymes, because they are

cultured in large quantities in short span of time and genetic manipulations can be

done on bacterial cells to enhance the enzyme production.

 

MICROBES IN INDUSTRIAL PRODUCTS:

 

VITAMINS & ORGANIC ACIDS:Vitamins are organic compounds that are capable of performing many life-sustaining functions inside our bodies. They are essential micronutrients which are required in small quantities for the body's metabolism. As our body cannot synthesize these vitamins, they need to be supplied through the diet.Apart from plants and animals sources, microbes are also capable of

synthesizing the vitamins. There are few groups of microbes living in the digestive tracts of both humans and other animals which are collectively called the gut microbiota.

These microbes are involved in synthesizing vitamin K. Other examples of microbial vitamins include ascorbic acid, beta-carotene, biotin, ergosterol,folic acid, vitamin B;-, thiamine, pantothenic acid, riboflavin, and pyridoxine.

 

Microbes are also used for the industrial production of certain organic acids. Citric

acid was the first discovered organic acids from microbial fermentation of lemon.

Organic acids are also produced directly from glucose. Aspergillus niger,Acetobacter and Lactobacillus are few examples of microbes used for the industrial production of organic acids.

 

SINGLE CELL PROTEIN:Single-cell protein (SCP) refers to protein derived from cells of microorganisms such as yeast, fungi, algae, and bacteria, which are grown on various carbon sources for synthesis. SCP is a protein source for human food supplements.

 

(a) Among algae, Spirulina is used most extensively.

 

(b) Fungi and yeast species, such as Aspergillus, Fusarium, Candida,Chaetomium, Trichoderma, Penicillium are good candidates for SCP production’

 

(c) Bacteria, such as Bacillus,Lactobacillus, Pseudomonas, Aeronomas are used for SCP.

 

MICROBES IN SEWAGE TREATMENT:

Municipal waste-water which contains large amounts of organic matter is called

Sewage.These treatment steps basically involve physical removal of large and small

particles. Initially, floating debris is removed by sequential filtration and then the grit is removed by sedimentation. All solids that settle form the primary sludge, and the

supematant forms the effluent.

 

SECONDARY TREATMENT OR BIOLOGICAL TREATMENT:

The primary effluent is passed into large aeration tanks where it is constantly

agitated which allows vigorous growth of useful aerobic microbes into flocs. These

are the masses of bacteria associated with fungal filaments to form mesh like

structures. While growing, the microbes significantly reduces the BOD (biochemical oxygen demand) which is the amount of oxygen required to oxidize total organic matter in the effluent.

 

The effluent is then passed into a settling tank where the bacterial ‘flocs’ are

allowed to sediment and the sediment is called activated sludge . A small part of

the activated sludge is pumped back into the aeration tank to serve as the inoculum.The remaining major part of the sludge is pumped into large tanks called anaerobic sludge digesters where other kinds of bacteria grow anaerobically which digest the bacteria and the fungi in the sludge.

 

During digestion, bacteria produce a mixture of gases such as methane, hydrogen sulphide and carbon dioxide which form biogas .The effluent from the secondary treatment plant is generally released into natural water bodies like rivers and streams.

 

MICROBES IN BIOGAS PRODUCTION:Biogas is a mixture of gases (containing predominantly methane) produced by the microbial activity.Certain bacteria grow anaerobically on cellulosic material and produce large amount of methane along with CO2 and H2

which are collectively called as methanogens. Examples. - Methanococcus and Methanospirillum.The major constituent of biogas with there percentage is given below:

Methane (CH,) 50-75%

 

Carbon dioxide (CO,) 25-50%

 

Nitrogen (N) 20-10%

 

Hydrogen (H.) 0-1%

 

Hydrogen sulfide (HS) O-3%

 

Oxygen (O,) 0-0.5%

 

MICROBES AS BIO - CONTROL AGENTS:

BIOCONTROL refers to the use of biological methods for controlling plant diseases and pests. Chemicals, insecticides and pesticides are extremely harmful to human beings and also these pollute our environment. The use of bio control measures will greatly reduce our dependence on toxic chemicals and pesticides.Bio control agents, useful in controlling plant diseases and pests are:

The ladybird, a beetle with red and black markings and dragon flies are useful to

get rid of aphids.

Trichoderma species are free-living fungi found in the root ecosystem these are effective as biocontrol agents of several plant pathogens.

aculoviruses are pathogens that attack insects and other arthropods and the ajority of baculoviruses used as biological control agents are in the genus ucleopolyhedrovirus.acillus thuringiensis is a bacterium and is a biocontrol agent against cotton fiworm insects. They produce a toxin that specifically kill the insect larvae when

he toxin is released in their gut.

 

Bacillus thuringiensis (Bt) bacteria synthesize different insecticidal proteins

named Cry proteins that are able to kill different insect orders, or nematodes.

These proteins have been extensively used in insect control practices in agriculture

as Sprays or expressed in genetically modified plants.

 

MICROBES AS BIOFERTILIZERS:Biofertilizers are organisms that enrich the nutrient quality of the soil. The main sources of biofertilizers are bacteria, fungi and cyanobacteria.Some microbes used as biofertlizers are:

 

(a) RHIZOBIUM form root nodules in leguminous plants and fix atmospheric nitrogen into organic forms, which is used by the plant as nutrient. Free living bacteria like Azospirillum and Azotobacter fix atmospheric nitrogen, hence increases nitrogen content of the soil.

 

(b) MYCORRHIZAE are the symbiotic association of fungus and roots of higher plants. The fungus absorbs phosphorus from soil and passes it to the plant.Plants having such associations show other benefits also, such as resistance to root-borne pathogens, tolerance to salinity and drought, and an

overall increase in plant growth and development. Thus it acts as a biofertilizer.

 

(c) CYANOBACTERIA are autotrophic microbes which can fix atmospheric nitrogen. Examples - Anabaena, Nostoc, Oscillatoria Blue green algae also add organic matter to the soil and increase its fertility.

 

(A) MULTIPLE CHOICE QUESTIONS:

 

1. Which microbe is used in the production of riboflavin?

a) Bacteria

b) Algae

c) Fungi

d) Virus

 

2. Process of biogas production is:

a) Aerobic process

b) Anaerobic process

c) Active process

d) Passive process

 

3. Single Cell Protein is rich in which of the following amino acids:

a) Histidine and valine

b) Histidine and glycine

c) Proline and leucine

d) Lysine and methionine

 

 

4. Amajor component of biogas is:

a) Ammonia

b) Methane

c) Ethane

d) Butane

 

5. Which of the following is not a biocontrol agent?

a) Baculovirus

b) Trichoderma

c) Spirulina

d) Bacillus thuringiensis

 

(B) Fill in the blanks:

1. ............18 the botanical name of baker's yeast.

2. Nostoc is used as ..............

3. The bacterium responsible for large holes in Swiss Cheese is .............

4. ..............grow in milk and convert it to curd.

5. The bacteria responsible for production of biogas are collectively called ..........

 

(C) True / False:

1. Aspergillus niger is used to produce citric acid

 

2. Biopesticides are those chemical agents that are used for control of weeds,

insects and pathogens.

 

3. The fruit juices available in the market are made clarified by treating them with

pectinases and proteases.

 

4. Trichoderma polysporum is used to produce blood cholersterol lowering agent

statins.

 

5. Rhizobia form root nodules in leguminous crops and some cyanobacteria form symbiotic association with the fern Azolla.

 

6. The sewage water is to be treated till the BOD is found to be high.

 

ANSWER KEY: PART-A

(A) MULTIPLE CHOICE QUESTIONS:

 

1. (c) Fungi

2. (b) Anaerobic process

3. (d) lysine and methionine

4. (b) methane

5. (c) Spirulina

 

(B) Fill in the blanks:

1. Saccharomyces cerevisiae

2. biofertilizers

3. Propionibacterium sharmanii

4. Lactic acid bacteria

5. Methanogens

 

(C) True / False:

1. True

2. False: Biopesticides are those biological agents that are used for control of

weeds, insects and pathogens.

3. True

4. True

5. True

6. False: The sewage water is to be treated till the BOD is found to be low.

 

PART: B SHORT ANSWER TYPE QUESTIONS:

1. What is the role of microbes in sewage treatment plant?

2. Name the water fern that is excellent biofertilizer for rice cultivation. What

helps the fern to do so?

3. Explain how Nucleopolyhedrovirus act as biocontrol agents?

4. Name the enzyme produced by Streptococcus bacterium. Explain its importance in medical sciences?

 

ANSWER KEY: PART - B

1. What is the role of microbes in sewage treatment plant?

Ans. A sewage treatment plant is regarded as gaint microbial culture where the

microbes are persuaded to work for our benefit. They metabolize the solid waste

that passes through the treatment plant. The microbes oxidise the nutrients and

during this process they release energy in the form of heat and chemicals (phosphates, nitrates and sulfates). Gaseous by product is also produced in the form of carbon dioxide.

 

2. Name the water fern that is excellent biofertilizer for rice cultivation. What helps the fern to do so?

Ans. An attractive cyanobacterial biofertilizer is AZolla. Anabaena symbiosis which is an excellent biofertilizer for rice cultivation. The atmospheric nitrogen is fixed by cyanobacteria - Anabaena azollae.

 

3. Explain how Nucleopolyhedrovirus act as biocontrol agents?

Ans. These viruses are known to infect the larval stages of many harmful insects.

These biological weapons are not only effective as potential biological control of

these insects but are also harmless to non target organisms.

 

4.Name the enzyme produced by Streptococcus bacterium. Explain its importance in medical sciences?

Ans. The enzyme produced is streptokinase. It is used for removing clots from

blood vessels of the patients who have undergone myocardial infarction.

 

PART: C LONG ANSWER TYPE QUESTIONS:

1. Discuss the various useful activities of microbes in obtaining various household

products.

2. Write about the role of microbes in the production of alcoholic beverages.

3. How can microbes be used as biocontrol agents?

4. What are biofertilizers? Name the different types of biofertilizers with example of each?

 

A206

 

         RECAPTULATION

MICROBES ARE PRESENT EVERYWHERE.

They are found in Thermal vents of geyser (Temp. above 100°C)

Deep in soil.

Under snow.

 

DIVERSE.

Protozoa, Bacteria, Fungi, Virus, Viroids, Prions (Proteinaceous infectious agents)

 

USEFUL: Antibiotics.

 

HARMFUL : cause diseases in humans, plants and animals.

 

IN HOUSEHOLD PRODUCTS -:-

Everyday : Lactobacillus (LAB) Lactic acid Bacteria — form curd from milk.

 

Increase Vit . B12 absorption.

 

Check disease causing microbes in our stomach.

 

Fermentation of dough for dosa, idli (CO2 produced)

 

Making bread —Baker's yeast. Saccharomyces cerevisiae.

 

Toddy made from sap of palm.

 

Cheese making (eg.Swiss cheesse by Propionibacterium sharmanii,Roquefort cheese by fungi.)

 

ININDUSTRIAL PRODUCTS:-Beverages and antibiotics.

EE Large vessels for growing microbes.

Fermented Beverages :-

 

Beverages like wine, bear, whisky, Brandy, Rum (Saccharomyces cerevisiae) Malted cereals and fruit juices used to produce ethanol, wine and beer produced without distillation. Whisky, brandy, rum produced after

distillation.

 

EE (Against life)

 

Penicillin produced by Alexander Fleming from Penicillium notatum while working with Staphylococci Earnest Chain and Howard Plorey awarded Nobel Prize in 1945 for establishing Penicillin as an effective antibiotic.

 

Uses : Treat diseases like plague, whooping cough, diphtheria, leprosy.

 

Chemicals : Enzymes and other Bioactivities Molecules:

 

USES

Aspergillus niger for production of Citric Acid.

 

Clostridium butylicum for production of Butyric Acid.

 

Lipases used in detergents to remove oil strains from Laundry.

 

Ee (0 clarify bottled jucies.

 

Streptokinase (from Streptococcus) as clot buster in patients with myocardial

infraction (heartattack).

 

ER an immuno-suppresant used in organ transplant patients (produced by Trichoderma polysporum)

 

[EM produced by yeast Monascus purpureus used as blood, cholesterol lowering agent.

 

MICROBES IN SEWAGE TREATMENT --

Why treatment necessary ?

 

Major component of waste water, human excreta.

 

Waste water sewage.

 

Cannot be disposed directly into rivers and streams.

 

Where & how ?

 

Before disposal sewage treated in sewage treatment plants (STPs)

 

Primary : Physical removal of particles large and small by filtration and sedimentation.

 

Solids — primary sludge.

 

Supernatant — effluent.

 

Secondary : Primary effluent taken to large aeration tanks.

 

Agitated mechanically and air pumped into it.

 

Aerobic microbes form masses with fungal filaments flocs.

 

Microbes consume organic matter in effluent for growth.

 

BOD ( Biological oxygen demand) reduced.

 

 

Passed into settling tank.

 

 

Bacterial flocs sedimented (activated sludge)

 

Small part of activated sludge used as inoculums in aeration tank.

 

Major part pumped into large anaerobic sludge digesters.

 

Anaerobic bacteria digest bacteria and fungi.

 

Bacteria produce gases such as methane, hydrogen sulphide and CO2—Biogas.

 

Secondary effluent released into rivers and streams.

 

Untreated sewage if released into rivers causes pollution.

 

Ministry of environment and Forests initiated, Ganga Action Plan and Yamuna Action Plan.

 

Process of sewage treatment in STP

a) Primary treatment(physical )

 b) Secondary treatment(biological)

 

Effluent loaded in large aeration tank, Agitation & rapid growth of aerobic

microbes (flocs) ,Consumes organic matter reduces BOD, Effluent passed to settling tank, Flocs sediments form — activated sludge(A.S.) Poured into sludge digester(small amount of A.S. used as inoculum) Filtration & sedimentation.

 

BIOGAS PLANT :-

Concrete tank 10- 15 meters deep, slurry or dung fed.

 

Floating cover placed above rises as biogas content rises.

 

Connecting pipe for supply of biogas.

 

Biogas is composed of Methane, Carbondioxide, hydrogen sulphides and ammonia.

 

Used for cooking and lighting.

 

Development by IARI :- Indian Agriculture Research institute & KVIC : Khadi and village Industries Commission.

 

MICROBES AS BIOCONTROL AGENTS °

 

Insecticides and Pesticides are toxic, harmful & environmental pollutants.

 

Natural predation better method.

 

No of pests kept in check, not totally eradicated.

 

Food chains not disturbed eg. Ladybird and Dragon flies useful to get rid of aphids and mosquitoes.

 

Bacillus thuringiensis (Bt) used to control butterfly caterpillar.

 

Mode of spores operation.

 

Available is sachets, mixed with water and sprayed on plants.

 

Eaten by insect larva

 

Toxin released in gut kills larvae.

 

Now Bt toxin genes introduced into plants — resistant to insect pests.e.g. Bt cotton.

 

Fungus trichoderma now being developed.

 

Nucleo polyhedrovirus good for narrow spectrum insecticide applications.

 

No negative impacts on plants, mammals, birds, fish or target insects.

 

For overall IMP (Intergrated pest Management) programme.

 

For ecologically sensitive areas.

 

Chemical fertilizers major pollutant.

 

Switch to organic farming and use of biofertilizers need of the time.

 

Main sources of biofertilizers. Bacteria, Fungi & Cyanobacteria. Eg Rhizobium

present in roots of leguminious plants fix atmospheric nitrogen into usable

organic form. Azospirillium and Azotobacter free living bacteria — fix atmospheric

Nitrogen.

 

 

Symbiotic associations are beneficial association of two different sp of

microorganism eg. Mycorrhiza, association of fungi and algae.

 

Fungal symbiont absorbs phosphorus from soil and passes it to plant.

 

Algal symbiont produces food.

 

Plants show

 

resistance to root — borne pathogens.

 

Tolerance to salinity and drought

 

Increase in growth and development.

 

Cynobacteria— autotrophic — fix atmospheric nitrogen

 

Imp.biofertilizer. e.g. Anabaena, Nostoc, Oscillatoria.

 

Blue green algae — increase fertility by adding organic matter.

 

No. of biofertilizers are commercially available.

 

FOR PRODUCTION OF BIODEGRADABLE PLASTICS -

biodegradable plastic, e.g. polyhydroxybutyrate (PHB) is being produced

commercially by fermentation with the bacterium Ailcaligenes eutrophus.

 

Production of PHB may be easily achieved in tree plants like populous, where PHB can be extracted from leaves.

 

Other main drawback of bacterial PHB is its high production cost, making it substantially very expensive than synthetic plastics.

 

AS EDIBLE VACCINES :-

the genes encoding the antigenic proteins of virus and bacteria can be isolated from the pathogens and expressed in plants.

 

such transgenic plants or their tissues producing antigens can be eaten for

vaccination/immunization (edible vaccines).

 

the expression of such antigenic proteins in crops like banana and tomato are

useful for immunization of humans since banana and tomato fruits can be eaten raw.

Example: cholera and hepatitis B vaccine.

 

2 MARKS QUESTION/ANSWERS ( Short Answer Type)

 

Q.1 What are Biopesticides? Give any two examples.

Ans . Biopesticides are biological control agents and their products are used to

control pests like weeds, insects and pathogens. Bioherbicides like Dalpon are used

to control broad-leaved weeds of cereal crops and Baculoviruses are bioinsecticide

viral pathogens that kill insects and other arthropods.

 

 

Q.2. The diagram shows a typical biogas plant.

1. Identify a, b and c.

2. Name the bacteria which produce biogas.

Ans. 1. a: Sludge tank

b: Gas holder

c: Charge pit

2. Methanogens like Methanobacterium. Methanogens grow anaerobically on

cellulosic material in cowdung to produce a large amount of methane, CO2 and Hz.

 

Q.3 Write the chemical composition of Bio gas.

Ans. [J is the combination of Methane, Carbon dioxide, hydrogen sulphide

and ammonia.

 

Q.4 What are biofertilisers? Give the significance of biofertilisers.

Ans. Biofertilisers are organisms that enrich the nutrient quality of soil.

1. Increase the soil fertility

2. Reduce the use of chemical fertilisers and in turn, the chances of environmental

pollution

Ans (a) Penicillium notatum

(b) Acetic acid

(c) Fungus

(d) Saccharomyces cerevisiae

 

Q.6 Name any two enzymes used in industry and state their uses.

Ans. 1. Protease Used in the leather industry in bating of hides, in textile industry for the removal of proteinaceous stains, in silk industry to liberate silk fibres etc.

 

2. Streptokinase Used as a clot buster for the removal of clots from the blood vessels of a heart patient by dissolving the intravascular fibrin.

 

Q.7 Explain how Bacillus thuringiensis act as biocontrol agents.

Ans. Bt toxin genes when introduced into a plant, the plant becomes resistant to

attack by insect pests. When these toxins are ingested by the insect larvae, they are

released in the insect gut where they become active and kill the larvae. Specific Bt

toxin genes obtained from [J are incorporated in several crop plants which make them resistant to insect pests.

 

Q.8 Why should biological control of pests and pathogens be preferred over the conventional use of chemical pesticides?

Ans. Biological control of pests and pathogens is preferred over the conventional

use of chemical pesticides because:

(i) The chemicals cause pollution of water bodies as well as groundwater. They

also enter the plant body through the soil.

(ii) The chemicals are extremely harmful to human beings and other animals.

 

 

Q.9 State any two properties of antibiotics.

Ans

(i) It should not kill the useful microbial flora found in the alimentary canal of man.

(ii) It should not cause any harmful side-effects in the host.

(iii) It Should have quick action and should be broad spectrum.

 

Q.10 Name a microbe used for statin  production. How do statins lower blood cholesterol level?

Ans Monascus purpureus is used for statin production. Statins lower blood cholesterol level by competitively inhibiting the enzyme responsible for the synthesis of cholesterol.

 

Q.11 Name the enzyme produced by  Streptococcus bacterium. What is its

importance in medical sciences.

Ans. Streptococcus bacterium produces streptokinase. It is used for removing

clots from the blood vessels of a patient suffering from myocardial infarction or in a heart patient.

 

Q.12 List the characteristics of an ideal pesticide.

Ans: An ideal pesticide should possess the following characteristics:

1. It should be inexpensive and easily available.

2. It should be effective only against the specific target organism.

3. It should be non-persistent.

4. It should be non-toxic to other living organisms.

5. It should be biodegradable.

 

Q.13 What are interferons?

Ans. Proteins released by cells in response to viral infection which they help to

combat are called interferons.

 

Q.14 Name any two free — living nitrogen fixing bacteria and symbiotic

nitrogen fixing bacteria.

Ans. Free living -

Symbiotic — Rhizobium , Frankia

 

Q.15 Name the fungus used as a biocontrol of plant diseases. Write its function.

Ans. Trichoderma. \t is successful for use as a biocontrol agent in various fungal

pathogens and in certain bacterial pathogens. It can form a close relationship with

the roots of the plant and colonise them. This invasion puts the fungus in a good

position to outdo and parasitize other fungi in the soil.

 

Q.16 What is Biodegradable Plastic? How it is obtained?

Ans: Biodegradable plastic, e.g. polynydroxybutyrate (PHB) is being produced

commercially by fermentation with the bacterium Ailcaligenes eutrophus.

 

Q.17 What are Edible vaccines?

Ans: The genes encoding the antigenic proteins of virus and bacteria can be

isolated from the pathogens and expressed in plants. These antigenic proteins

are introduced in banana and tomato useful for immunization of humans.

 

Q.18 Name the different vitamins which are produced by micro-organisms.

Ans: 1. RE is produced by yeast and bacteria.

2. EE is produced by bacteria and actinomycetes.

 

Q19. What for Nudeopolyhedra viruses (NVP) are being used nowadays?

Ans viruses are being used to kill insects and other arthropods pests of crops. The viruses have no effect on plants and non-target animals.Thus used in biological control of pests.

 

Q20. Name the bioactive molecules produced by Trichoderma Polysporum and Monascus Purpureus.

Ans: (a) Bioactive molecules produced by Trichoderma polysporum cyclosporin

A. It is used as an immunosuppressive agent in organ- transplant patients.

 

(b) Bioactive molecules produced by Monascus Purpureus are statins. It is a blood cholesteroltowering agent

 

A207

 

            RECAPITULATION

Microbes are present everywhere even under extreme conditions, where no other life-form could exist.

 

They are diverse and include viruses, bacteria, protozoa, fungi, viroids,

prions and other microscopic animals.

 

They may be pathogenic but have an important role to play in human welfare.

 

We use microbes and microbially derived products almost every day in household products. Bacteria called lactic acid bacteria (LAB) grow in

 

milk to convert it into curd. The dough, which is used to make bread, is

fermented by yeast called Saccharomyces cerevisiae. Certain dishes such as idli and dosa, are made from dough fermented by microbes.Bacteria and fungi are used to impart particular texture, taste and flavor

to cheese.

 

Microbes are used to produce industrial products like lactic acid, acetic

acid and alcohol, which are used in a variety of processes in the industry.Antibiotics like penicillins produced by useful microbes are used to kill disease-causing harmful microbes. Antibiotics have played a major role in controlling infectious diseases like diphtheria, whooping cough and pneumonia.

 

For more than a hundred years, microbes are being used to treat sewage (waste water) by the process of activated sludge formation and this helps in recycling of water in nature.

 

Methanogens produce methane (biogas) while degrading plant waste.Biogas produced by microbes is used as a source of energy in rural areas.

 

Microbes can also be used to kill harmful pests, a process called as biocontrol. The biocontrol measures help us to avoid heavy use of toxic pesticides for controlling pests. There is a need these days to push for

use of biofertilisers in place of chemical fertilisers.

 

Itis clear from the diverse uses human beings have put microbes to that they play an important role in the welfare of human society.

 

2 MARKS Que/Ans (Short Answer Type)

 

Q. 1 Discuss the role of LAB in producing curd.

Ans. Lactobacillus lactis , Lactobacillus acidophilus and Streptococcus lactis

bacteria produce lactic acid which cause coagulation of milk protein called

casein and change milk into curd.

 

Q.2 What is the role of baker’s yeast in the production of bread ?

Ans. Saccharomyces cerevisiae ( Baker's yeast causes the alcoholic fermentation of sugar in wheat flour and produce ethanol and carbondioxide .Carbondioxide gives puffy appearance to the bread when baked.

 

Q.3 Name some diseases which can be cured by antibiotics.

Ans. Plague, Whooping Cough, Diphtheria and Leprosy.

 

Q.4 Name the bioactive molecule produced by yeast Monoascus

purpureas. Give its significance.

Ans. The bioactive molecule produced by the yeast is Statins.Significance: Statins have been commercialized as blood cholesterol

lowering agents. It acts by competitively inhibiting the enzyme responsible for

synthesis of cholesterol.

 

Q.5 Name the source of Cyclosporin A. How does this bioactive molecule function in our body?

Ans. The fungus Trichoderma polysporum is the source of cyclosporin A. it is used as immunosuppressant to decrease the chances of failure of organ transplantation.

 

Q.6 BOD value of A, B &C water samples is 30mg/L,08mg/L& 500mg/L respectively. Which sample is most polluted? Also label these correctly as River Water, Untreated Sewage Water & Secondary effluent discharge from a STP.

Ans. Sample C is most polluted because BOD value is highest.

Sample A---Secondary effluent discharge from a STP.

Sample B---River water

Sample C---Untreated sewage water.

 

Q. 7 What is the key difference in Primary and Secondary sewage treatment?

Ans. Primary Treatment

 

1)lt is a physical process

2)Filtration and sedimentation of Sewage water is done

 

Secondary/Biological Treatment

1)It is a biological process

2)Organic waste is digested by Microbes (Bacteria & Fungi).

 

Q.8 What is sewage? In which way sewage be harmful to us?

Ans. Sewage is the municipal waste matter that is carried away in sewer or

drains. Sewage contains toilet, bathroom & kitchen waste.

Harmful effects of sewage-

1)Pathogenic microbes are present in it.

2)Sewage water can pollute drinking water due to leakage in pipes.

 

Q.9 What are the disadvantages of chemical pesticides ?

Ans. i. They are toxic and extremely harmful to human beings and animals.

ii. They pollute environment,vegetables, fruits and crop plants.

 

Q.10How dragonflies act as biocontrol agent ?

Ans. Dragonflies feed upon mosquitoes. Hence they act as biocontrol agent by helping to get rid off them.

 

Q.11 What are baculoviruses ? Mention their role as biocontrol agent ?

Ans. Baculoviruses are pathogens that attack insects and other arthropods.Most of them belongs to genus Nucleopolyhedrovirus. They are species specific,narrow spectrum insecticides. They do not show negative

impacts on other organisms.

 

Q.12 What are biopesticides ? Give one example.

Ans. Biopesticides are biological agents and their products that are used to

control insects and other pests.For example Baculoviruses.

 

Q.13 What are Bio fertilizers?

Ans.

 

 

Q.14 Define Mycorrhizae. How are the partners mutually beneficial to each other?

Ans. Mycorrhizae is a symbiotic association between fungus and plant roots.The fungal hyphae act as root hairs and increase the surface area for water absorption and organic compounds.Plant provide the fungus shelter and food formed during the process of photosynthesis.

 

Q.15 Where do you find such type of roots as shown in the diagram?What is the role played by them?

Ans. Such type of nodulated roots are found in Leguminous plants-family Fabaceae. In these roots reside bacteria Rhizobium symbiotically helping in fixation of atmospheric nitrogen into nitrites.

 

Q.16 Give major disadvantages of Bio fertilizers.

Ans. Biofertilizers release nutrients very slowly and are unable to meet any

specific nutrient deficiency of the soil.

 

Q.17 Give classification of bio fertilizers with one example of each group.

Ans. Types of Biofertilizers:

1.Symbiotic Biofertilizers found in roots of Legume plant-Rhizobium.

2.Bacteria found symbiotically in loose association of Grasses-Azospirillum

3.A free living Nitrogen-fixing bacteria-Azotobacter

4.Blue-green algae(Cynobacteria) as Nitrogen-fixers-Anabaena

5.Symbiotic association between Fungus and roots of higher plants-Mycorrhizae.

 

Q.18 What is the principle of biogas ?

Ans. Biogas is generated when bacteria degrade biological material in the

absence of oxygen in a process known as anaerobic digestion.

 

Q.19 Why does ‘ Swiss cheese ‘ have big holes?

Ans. Due to emission of Carbondioxide gas during fermentation of Swiss cheese by Propionibacterium sharmanii.

 

Q.20 What is the use of spent slurry?

Ans. The spent slurry may be used as fertiliser as it is rich in nitrogenous and

phosphorus compounds.

 

A208

 

Dear students , in this revision sheet we will understand about the different roles played by MICROBES. When you attempt 3 MARK

questions certain points should be kept in mind i.e. we should write the name of microbe for its role. There should be no generalisation of different catagories while describing their role e.g. if we write- microbes are used in many industrial projects and we donot mention the particular

microbe, iit will not get you proper score. Here are some questions with

possible answers for you to revise the points.

 

3 Marks Questions

 

1) How does milk is converted to curd?

A small amount of curd called inoculum or starter is added to fresh milk or

lukewarm milk. This inoculum contains LAB- Lactobacillus bacteria. This bacteria

converts milk to curd at suitable temperature conditions.

 

2) Write about role of baker’ s yeast in production of bread

The dough used for making bread is prepared by kneading wheat flour anda _ small

quantity of baker’s yeast . Baker's yeast help in fermentation of dough. Fermenting

results in release of ethyl alcohol and carbon dioxide that makes the bread porous

and soft.

 

3) How do swiss cheese get large holes?

The large holes in swiss cheese are due to production of a large amount of carbon

dioxide by a bacterium named Propionibacterium sharmanii.

 

4) Discuss the role of microbes in industry.

Many industries are based on microbial activity —

 

a)baking industry — many of the baked eatables like, bread,cake or cookies are

prepared from fermented dough.

 

b) Fermented beverages like wine and beer are obtained by fermenting malted cereals and fruit juiceswith Sachchraroyces cerevisiaeor brewer's yeast.

 

c)Antibiotics and Vaccines are produced by using some live or dead microbie.Production off many bioactive molecules is dependent on microbes e.g.Cyclosporin-A produced by Trichoderma polysporum.

 

d) Food industry is also dependent on microbes when it comes to cakes, bread ,

cheese, dosa and idli comes.

 

e) Single cell protein are also yielded from microbes i.e. Pseudomonas grown on

petroleum products.

 

5) Write about organic acids produced by microbial activity.

Following organic acids are produced by microbial activity-

Citric acid- Aspergillus niger (fungi)

Aceticacid- Acetobacter aceti (bacteria)

Butyriic acid-Clostridium butylicium ( bacteria)

Lactic acid- Lactobacillus ( bacteria)

 

6) Discuss the role of microbes in production of enzymes.

A) Lipase used indetergent formation

B) Pectinase and Proteases used for clarifying bottled juices.

C) Streptokinase produced by Streptococcus

 

7) Enlist the diseases that are cured by microbes based medicines.

Plague — Streptomycin( bacteria based)

Whooping cough — azithromycin (bacteria based), erythromycin ( bacteria based)

Diptheria — erythromycin( bacteria based) penicillin (fungi based)Leprosy — Dapsone, clofazamine (bacteria based)

 

8) Which bio- insecticides is based upon Fungi used on large scale?

Large scale production and use of fungi based insecticides is common these days.

Beauveria bassiana ( B) is used to control pests. The fungus is not harmful for

warm blooded organisms as it does not grow in them. It becomes inactivated in Sun’s

ultraviolet rays in one to eight weeks.

 

9) How do microbes survive higher temperatures?

Thermophiles are ancient forms of bacteria found in hot water springs and deep sea

hydrothermal vents. They contain specialised resistant enzymes, branched chain

lipids in cell wall etc. These enzymes donot get denatured or destroyed at much

higher temperature.

 

 

10) What do you understand by alcoholic fermentation?

Alcoholic fermentation is the anaerobic process in which alcohol and carbon dioxide

are evolved from nutrient containing micro organisms. In the first step , mash is

prepared by mixing hot water with crushed cereals and potatoes. The mash turns

into sweetened material called wort. Wort is then inoculated by yeast to ferment.

 

11) Alcoholic production produces variety of beverages. How is it possible?

Production of different type of beverages depends on following factors :

a) on the type of raw material used for fermentation.

b) The type of processing i.e. with or without distillation.

c) The type of inoculum used

 

12) Mention some of uses of LAB in curd.

LAB is Lactobacillus bacteria found in curd.

a) LAB converts milk into curd at suitable temperature.

b) It improves nutritional quality by increasing vitamin B12.

c) Checks growth of disease causing microbes in stomach.

 

13 ) Discuss role of microbes in the production of household products.

a) LAB is used to produce curd from milk.

 

b) Yoghurt is produced by curdling milk with the help of Streptococcus thermophilus and Lactobacillus bulgaricus.

 

c) Butter Milk is formed by inoculating skimmed milk with Streptococcus cremoris

or Leuconostoc species.

 

d) Different types of cheese are made with different inoculum with change in

procedure of making.

 

e) Bread , cakes and cookies are made with selected sttrains of Saccharomyces

cerevisiae grown on molasses used as Baker's yeast.

 

f) Dosa, upmma, idli, Tempeh, Tofu and Sufu are made after fermenting the raw

material with the help of microbes.

 

14) Write in detail about SCP.

SCP are single cell proteins. Spiriluna, yeast and Fusarium are common SCP. These

are used as human food or animal feed. These are high quality protein poor in fats.

 

15) What are transgenic bacteria?

Transgenic bacteria are genetically modifiedbacteria whereforeighn desirable

genesare introduced e.g. genetically modified streptococcus produce enzyme

streptokinase. E.coli used for engineered insulin.

 

16) Write a note on bioactive molecules.

a) Cyclosporin -A produced by Trichoderma polysporum is used as immunosuperessive agent

 

b) Streptokinase is produced by bacterium Strepococcus.

 

c) Statins produced by Monascus purpureus yeast is used as blood cholesterol

lowering agent.

 

17) Write a note on cheese industry.

There are several varities of cheese with different texture , flavour and taste.

 

a) Raw cheese is prepared by curdling of milk with LAB. The curd is heated to

separate cheese from whey.

 

b) Cottage cheese is prepared by inoculation of skimmed milk with cheese culture

and adding Rennin after 1-2 hours.

 

c) Ripened cheese is prepared from cottage cheese. It is first dipped in

brine,wiped and then matured with different strains of bacteria and fungi.

 

d) Large holed swiss cheese is prepared by using bacterium named Prppionbacterium sharmanii.which produces enough carbondioxide to make the cheese porous and soft.

 

e) Roquefort cheese is prepared by using Penicillium roqueforti.

 

f) Camembert cheese production involves use of Penicillium camemberti.

 

18) Where you can find microbes ?

Microbes are everywhere- in soil, water, air, inside our bodies and in all the

organisms. These are present everywhere and even at sites where no other life form

can not exist. Some of these can tolerate very high temperatures and some can

survive under the deep layers of snow. Some varieties of microbes can be found in

saline mediums and some in highly acidic environments.

 

19) How diverse are microbes.?

Microbes are diverse. These may be protozoans, bacteria, fungi , viruses, viroids and prions. Microbes like bacteria and many fungi can be grown on nutritive media.When they grow and form colonies that can be seen with naked eyes.

 

20) How was Penicillin discovered?

Alexander Fleming was working on Staphylococci bacteria. He observed a mould

which was preventing the growth of bacteria. This mould was Penicillium notatum.

He named the chemical released by mould — Penicillin. Ernest Chain and Howard

Florey used it as antibiotic to treat soldiers. Fleming, Chain and Florey were awarded Nobel Prize in 1945 for this discovery.

 

A209

 

            RECAPITULATION

Microbes are present everywhere even under extreme conditions, where no other life-form could exist.

Microbes are used to produce industrial productslike lactic acid, acetic acid and alcohol, which are used in a variety of processes in the industry.Antibiotics like penicillins produced by useful microbes are used to kill disease-causing harmful microbes. Antibiotics have played a major role in controlling infectious diseases like diphtheria, whooping cough and pneumonia.

Methanogens produce methane (biogas) while degrading plant waste.Biogas produced by microbes is used as a source of energy in rural areas.

 

Microbes can also be used to kill harmful pests, a process called as biocontrol. The biocontrol measures help us to avoid heavy use of toxic pesticides for controlling pests. There is a need these days to push for

use of biofertilisers in place of chemical fertilisers.

 

Itis clear from the diverse uses human beings have put microbes to that they play an important role in the welfare of human society.

 

3 MARKS Que/Ans(Short Answer Type)

Q. 1 What are bio fertilizers, what are advantages of using bio fertilizers

in agriculture?

 

Ans. Bio fertilizers are living organisms that enrich the nutritive quality of soil.

They are the substance that contains microorganism’s living or latent cells.

Bio fertilizers increase the nutrients of Lost Plant when applied to their seed,

plant surface or soil.

 

Advantage

1. Helping to make plant nutrients more available to the plants.

2. They are eco friendly.

3. Increase crop yield by 20-30%.

4. Improve soil texture and water holding capacity and restore natural soil

fertility.

 

Q.2 Define biological control give its significance.

Ans. Biological control in a method of controlling pests such as insects,

weeds and plant diseases by using other organisms.

 

Significance:- Biological control agent give protection to crop throughout the

crop period. They don't cause toxicity to the plants. It is harmless to human being and animal (Environmentally safe) and neither effect the soil productivity.

 

Q.3 What is chemical Composition of biogas ?

Ans. Chemical Composition of biogas is:

Methane = 50-68%

Hydrogen = 1-5%

Carbon dioxide = 25-30%

Nitrogen = 2-7%

Oxygen = 0.0-0.1% and rarely H2S.

 

Q.4 a) What are methanogens ?

 

(b) Name the animal in which methanogens occur

Ans. a) Methanogens are anaerobic bacteria which produce methane.Example — Methanobctrium.

 

b) They are present on gut of ruminates and help in digestion of cellulose rich diet of cattle.

 

Q.5 Explain why some microorganisms are called bio fertilizers. Give two examples.

Ans. Certain Bactria and Cyan bacteria are nitrogen fires. They connect atmospheric free nitrogen into ammonium from which in easily assimilated by higher plants. Their these microorganisms increase the fertility of — soil without causing any environmental hazards and therefore, called bio

fertilizers.

Examples — Rhizobium and Anabaena.

 

Q.6 Why do farmers prefer bio fertilizers to chemical fertilizers these days? Explain.

Ans. Biofertilizers is preferred over chemical fertilizer because.

 

1. Bio fertilizer would be better in the long run because they contain chemical substances that when used in Excess become harmful to the consumers.

 

2. Continuous application of fertilizer to the soil decreases its fertility and

also leads to increases in the acidity of soil. While bio fertilizers enrich the

quality of soil.

 

Q. 7 Howdo Anabaena and mycorrhiza acts as biofertilizers ?

Ans. Cyan bacteria such as Anabaena fix atmospheric nitrogen and act as bio fertilizers especially inn paddy filed.

Fungi such as glomus from symbiotic association with plants. This relationship in known as mycorrahiza. They absorb phosphorus from the soil and pass it to the plants.

 

Q.8 Organic farmers prefer biological control of diseases and pests to the use of chemicals for the same purpose Justify.

Ans.1. Biological method do not kill the useful and harmful life farmers

indiscriminately.

 

2. They are not toxic to human being

 

3. It does not cause pollution in environment.

 

4. It does not affect the natural predator prey relationship and food chains

 

Q.9 Give on example of a bacterium, a fungus and an insect that are used as bio control agent.

Ans. Bacteria — Bacillus thuringiensis

Fungus — Tricheduma

Insects — Ladybird beetle and dragon flies.

 

Q.10 What are the use of biogas plant ? draw a well-cabled diagram.

Ans. Biogas in used as fuel for heating and cooking lighting , power of irrigation and other purpose as _ an alternative of firewood , terosense stung cakes’ or even electricity and LPG. It is considered as eco friendly and

pollution free source of energy.

 

1. Biogas is commercially produced inside the biogas plants which are mainly build in rural areas.

2. The plant in fed with a mixture of dung and nature (I:i)

3. Each biogas plant consists of concrete tank covered by a floating lid.

 

Q.11 Explain why some microorganisms are called bio fertilizers. Give two examples.

Ans. Certain bacteria and cyanobacteria are nitrogen fixes. They concert free

nitrogen into ammonium form which in easily assimilated by higher plants.Thus , these microorganisms increase the fertilizer of soil without causing any environmental hazards and therefore, called bio fertilizers.Examples- Rhizobium and Anabaema.

 

Q.12 What is the biological significance of Azolla pinnata in agricultural ?

Ans. 1. It contains cyanobacterium which grow as symbiotic within the cavities formed in upper lobes of aerial chlorophyllous.

2. It has ability to absorb certain amount of heavey metal such as lead from the contaminated water thus presenting bio magnification.

3. It seems as an excellent bio fertilizer wnen grown in association with rice.

 

 

Q.13 Differentiate between conventional and organic pest control method.

 

Q.14 Why is Rhizobium categorized as a ‘symbiotic bacterium? How does act as a bio fertilizer?

Ans. Rhizobium is associated with roots of leguminous plants where it produces nitrogen into an organic form. It is a bio fertilizer as it is a living organism that enriches nutrient content of plant and obtain food and shelter from the plant and the plant get fixed nitrogen in return. So both line in a

symbiotic relationship.

 

Q.15 How to mycorrhizae acts as bio fertilizer ? explain name the genu

of fungi that farms a mycorrhizal association with plants.

Ans. Mycorrhizae is a symbiotic association of a fungus with the roots of higher from soil and passes it to the plant It also provides resistance to the root borne pathogen and increases tolerance of plant to salinity and drought Genus of Fungi — Glomus

 

Q.16 What are the advantage of Biogas ?

Ans. 1. It provides both energy and manure.

2. It is storable form of energy which can be used more efficiently and economically.

3. Biogas use does not add to pollution.

 

Q.17 what are bio pesticides ? Give examples Microbial bio pesticides constitutes the various .

Ans. Microorganism like bacteria , fungi, various protozoa and algal which are used to combat variety of pets causing destruction of agriculture economy.

 

Q.18 What are types of patricides?

Ans. Types of pesticides

1. Insecticides — Insect

2. Herbicides — Plants

3. Rodenticides — Rodents

4. Bactericides — Bacteria

5. Fungicides — Fungi

6. Larvicides — Lamae.

 

Q.19 What is the difference between pathogen and parasite ?

Ans. The difference between pathogen and parasite is easy to understand.Pathogen in an organism that cause diseases to the host after infection.Parasite is an organism that depends on another host living organism for its life cycle.

 

Q.20 What is natural Insecticides?

Ans. Natural Insecticides contain chemical, mineral and biological materials

and some products are available commercially e.g. pyrethrum, neem ,spinosad , rotenone , abamection, BT, garlic, cinnamon, pepper and

essential oil products.

 

 

A210

 

Important Instructions :

 

1. There are a total of 17 questions and four sections in the question paper. All questions are compulsory.

 

2. Section A contains question numbers 1 to 5 very short answer type questions of one mark each.

 

3. Section B contains question numbers 6 to

13, short answer type questions of two marks each.

 

4. Section C contains question numbers 14 to 16, short answer type II questions of three marks each.

 

5. Section D contains question number 17, long answer type question of five marks. There will be internal choice in this question.

 

6. There is no overall choice in the question paper

 

Section-A

Each question carries 1 mark

 

Q.1. Why are there big holes in ‘Swiss cheese’?

Q.2. What is a fermentor?

Q.3. Which states are involved in the Ganga action plan?

Q.4. Roquefort cheese is obtained from which of the species of Penicillin?

Q.5 Name the plant whose sap is used in making Toddy. Mention the process involved in this.

 

Section-B

Each question carries 2 marks

 

Q.6. Name two alcoholic drinks produced in each of the following ways

(i) by distillation and (ii) without distillation.

 

Q.7. What is the key difference between primary and secondary sewage treatment?

 

Q.8. Do you think microbes can also be used as source of energy? If yes, how?

 

Q.9. Common yeast is known as Baker’s yeast and also as Brewer’s yeast. Justify.

 

Q.10. Describe broad-spectrum antibiotic. Give an example.

 

Q.11. What is another name used to address the viruses parasitizing bacteria?

 

Q.12. How are cyanobacteria used in the fields of paddy?

 

Q.13.What is the significance of floes in the biological treatment of wastewater?

 

Section-C

Each question carries 3 marks

 

Q.14. What is the role of microbes in reducing environmental degeneration caused by chemicals?

 

Q.15. Giving two examples describe biofertilizers.

 

Q.16. Describe the procedure involved in Sewage treatment?

 

Section-D

Each question carries 5 marks

 

Q17. Role of Microbes in industrial products.

OR

Q18. What is Biogas? How is it produced & Name the microbes invaded in Biogas production?

 

ANSWERS

SECTION-A

 

A.1. It is because of the bacterium named Propionibacterium shermanii that releases large amounts of carbon dioxide.

 

A.2. To cater to large scale production of biotechnological products such as beverages and antibiotics in industries, microbes are grown in large vessels

 

A.3. Jharkhand, UP, Bihar, West Bengal.known as bioreactors or fermentors.

 

A.4. Fungi Penicillium roqueforti

 

A.5 The sap of a palm tree is used in making Toddy and the process is called fermentation.

 

SECTION-B

 

Ans 6. (i) Whisky, brandy, rum — by distillation

(ii) Wine, beer — without distillation

 

Ans 7. There are three stages of sewage treatment: primary,secondary and tertiary. Primary treatment is a physical process while

secondary is a biological process and tertiary is a chemical process.

 

Ans 8. Yes, the microbes present in activated sludge are digested anaerobically to generate a biogas i.e. by release of inflammable

biogas in biogas plant, which is a source of energy.

 

Ans 9..Common yeast is employed in the fermentation of —

(i) dough, used for making bread, cakes in bakeries.

(ii) Fruit juices and malt in breweries for the production of alcoholic beverages, hence it is known as both as baker’s and brewer’s yeast.

 

Ans 10. It hinders the maturity of both gram-negative and gram-positive

bacteria. Example — Jetracyclines, Phenicols, Fluoroquinolones.

 

Ans 11. Bacteriophages. They are viruses which do not eat bacteria.They infect and replicate within the bacteria

 

Ans 12. They fix nitrogen from the atmosphere and supplement organic matter to increase the fertility of the soil. Examples — Nostoc, Anabaena,Oscillatoria

 

Ans 13.They are portions of bacteria related to fungal filaments which form mesh-like structures. It helps in digestion of organic matter, eliminate pathogens and liberate nutrients in the sewage effluents.

 

SECTION-C

 

Ans14. Microbes are being used as pesticides and fertilizers to reduce environmental degradation and are called as biopesticides and biofertilizers respectively. As biofertilizers, microbes enrich soil

nutrients by fixing atmospheric nitrogen in the soil, examples —Azospirillum, Azotobacter, Rhizobium etc. As biopesticides(Bacillus thuringiensis) they check the growth of insect pests. A fungal species —

Trichoderma is effectively used as a biocontrol agent for many plant pathogens. Baculovirus in genus nucleopolyhedrovirus is used as a biological control agent for narrow spectrum, species-specific insecticidal applications.

 

Ans.15. Biofertilizers supplement the nutrient quality of the soil.Their main source is fungi, bacteria and cyan bacteria. Fizotobacter,Rhizobium can tix atmospheric nitrogen in the soll. Blue-green algae

like Nostoc, Anabaena add organic matter to the soil and increase soil fertility.

 

Ans:16 The following technique is performed for the treatment of sewage waste:

 

i) PRIMARY TREATMENT: This entails physically separating suspended materials in settling tanks in order to reduce BOD. The raw sewage is routed into massive open tanks

where it is subjected to anaerobic digestion to remove the solid fraction.

 

ii) . SECONDARY Therapy - Secondary treatment relies on microbial activity,

 

iii) either aerobic or anaerobic. Secondary treatment techniques include:Sand filters for filtration Process of aeration Application of oxidation ponds:After drying, the sludge that collects after secondary treatment is

disposed of, and the efferent is allowed to be used for tertiary treatment.TERTIARY TREATMENT: This treatment comprises chemical treatment to

 

iv) eliminate inorganic chemicals as well as pathogenic microorganisms. Chlorination is the most common disinfection procedure.

 

SECTION-D

 

Ans.17 Microbes in industrial production

A number of products like beverages and antibiotics involve uses of microbes. Production on large scale requires growing microbes in very large vessels called fermenters.

a. Fermented Beverages- Saccharomyces cerevisiae used for bread-making

 

b. and commonly called brewer's yeast, is used for fermenting malted cereals and fruit juices, to produce beverages like wine, bear,

whisky and rum.. Wine and bear are produced without distillation whereas whisky, brandy and rum are produced by distillation of the

fermented broth.

 

c. Antibiotics- they are chemical substances produced by some microbes

 

d. and can kill or retard the growth of other microbes. Penicillin was first antibiotic to be discovered. Antibiotics have great improved our capacity to treat deadly diseases such as plague, whooping cough,

diphtheria and leprosy.

 

c. Chemical, Organic acids , Enzymes and other Bioactive Molecules are

commercially produced by microbes.

Chemicals :Aspergillus niger (fungus) — Citric acid

Acetobacter aceti (bacterium) — Acetic acid

Clostridium butylicum (bacterium) — Butyric acid

Lactobacillus (bacterium) — Lactic acid

Saccharomyces cerevisiae — Ethanol

Enzymes:

Lipase — used in laundry detergents

Pectinase and protease — used in bottled juices

Streptokinase (Streptococcus bacterium) — used as clot buster (to remove clots)

 

Bioactive molecules:

 

Cyclosporin A (Trichoderma polysporum fungi) — used as immunosuppressive agent (for organ transplant patients).

 

Statins (Monascus purpureus yeast) — used as blood cholesterol lowering agents

 

Ans,18. Biogas is the gas produced by anaerobic fermentation of waste

biomass. It is made up of methane, CO2, hydrogen, nitrogen, oxygen,and hydrogen sulphide, among other things. Microbes that are often employed in the production of biogas-

 

i) hydrolytic bacteria, such as cellulosomes, clostridium, etc.

 

ii) Bacteria that produce hydrogen sulphide, such as Syntrophomonas wolfei

 

iii) Methanobacterium Omelianskii is an example of a methanogenic bacteria.

The biogas plant is fed by a concrete tank. The slurry is covered with a floating cover, which continues to rise when gas is created in the tank owing to microbial activity. The biogas plant includes an output that

connects to a pipe that distributes biogas to surrounding residences.Microbes transform the organic part of biodegradable organic solid

waste and trash into energy in the form of biogas and humus during biogas production.

CO + H,O — CO, + H,

CO, +4H, — CH4 + 2H,O

CH30H — CH4 + 02

Chapter 10 Microbes in Human Welfare