- Micro-organisms are ideal for industries due to their fast growth, high metabolic activity, and enzyme diversity.
- They are grown in large vessels called fermenters for large-scale production.
- Microbes are used to produce medicines like steroids, vaccines, human insulin, and immunosuppressive drugs.
- Many important antibiotics such as penicillin, streptomycin, tetracycline, and erythromycin are obtained from microbes.
- Microbial fermentation is used to produce vitamins (B₁₂, riboflavin) and human proteins using recombinant DNA technology.
- Several organic acids (citric, lactic, acetic) and amino acids (lysine, glutamic acid) are industrially produced by microbes.
- Microbes produce enzymes used in detergents, food processing, textiles, medicines, and plastic industries.
- Yeasts are widely used for producing ethanol and fermented beverages like beer, wine, whisky, and rum.
Definitions [4]
Define the following term
Zymology
Zymology is an applied science which deals with the biochemical process of fermentation and its practical uses.
Define the following term
Antibiotics
Antibiotics are chemical substances produced by microorganisms which can kill or retard the growth of other disease causing microbes even in low concentration. Antibiotic means “against life”.
Define the following terms
Superbug
"Superbug" is a term used to describe strains of bacteria that are resistant to the majority of antibiotics commonly used today.
Define bioherbicides.
Bioherbicides are living creatures such as microbes, fungi, insects, or other pathogens that are employed to restrict the population of undesired plants in agricultural fields, ponds, lakes, and so on.
Key Points
Key Points: Microbes in Household Products
| Product | Micro-organisms Used | Function |
|---|---|---|
| Curd | Lactobacillus (LAB) | Converts milk into curd, increases vitamin B₁₂ |
| Butter | Streptococcus cremoris, Leuconostoc dextranicum | Gives flavour and aroma |
| Yogurt | Lactobacillus bulgaricus, Streptococcus thermophilus | Ferments milk at 40°C |
| Cheese | Streptococcus lactis, Leuconostoc, fungi | Curdling and ripening of cheese |
| Swiss Cheese | Propionibacterium shermanii | Produces CO₂, forms holes |
| Roquefort Cheese | Penicillium roqueforti | Ripening and flavour |
| Camembert Cheese | Penicillium camemberti | Soft texture and taste |
Key Points: Microbes in Food Production
| Food Item | Micro-organism Used | Role |
|---|---|---|
| Dosa / Idli | Bacteria | Fermentation produces CO₂, dough rises |
| Bread | Saccharomyces cerevisiae | CO₂ production, leavening |
| Sausages | Lactic acid bacteria | Meat fermentation |
| Sauerkraut | Enterobacter, Leuconostoc, Lactobacillus | Cabbage fermentation |
| Soy sauce | Aspergillus oryzae | Fermentation of soybeans |
| Tempeh | Rhizopus species | Fermented soybean food |
| Tofu / Sofu | Mucor species | Cheese-like product |
| Toddy | Yeast | Fermentation of palm sap |
Key Points: Microbes in Industries
Key Points: Microbes in Sewage Treatment
- Sewage treatment is carried out in two stages: primary treatment and secondary (biological) treatment.
- Primary treatment involves physical removal of floating debris by filtration and heavy particles by sedimentation, forming primary sludge and effluent.
- In secondary treatment, the effluent is aerated in large tanks to promote growth of aerobic microbes that consume organic matter.
- Microbial activity reduces the BOD (Biochemical Oxygen Demand), thereby decreasing the polluting potential of sewage.
- The settled activated sludge is digested anaerobically to produce biogas, and the treated effluent is released into natural water bodies.
Key Points: Ganga and Yamuna River Pollution Control Initiatives
| Aspect | Ganga Action Plan | Yamuna Action Plan |
|---|---|---|
| Reason | To control pollution due to untreated sewage and waste | To reduce pollution caused by sewage discharge |
| River | River Ganga | River Yamuna |
| Length / Area | About 2,500 km (Gangotri to Bay of Bengal) | States of U.P., Delhi, and Haryana |
| Launched | 1986 | April 1993 |
| Launched by | Late Prime Minister Rajiv Gandhi | Government of India |
| Main Objective | Improve water quality of river Ganga | Control pollution of river Yamuna |
| Key Measures | Sewage interception, diversion, treatment plants | Construction of sewage treatment plants |
| Recent Initiative | Namami Gange Project | Continued under Yamuna Action Plan |
Key Points: Microbes in Energy Generation
- Microbes help in energy production by synthesizing fuels such as ethanol, methane, hydrogen, and hydrocarbons.
- Gasohol, a mixture of gasoline and alcohol, is produced using microbes like Zymomonas mobilis and Thermoanaerobacter ethanolicus.
- Biogas is mainly methane produced by methanogenic bacteria such as Methanobacterium during anaerobic fermentation of cattle dung.
- Biogas plants use dung slurry to generate gas for cooking and lighting, while the leftover slurry serves as a good fertilizer.
- Some algae produce hydrogen gas from water in sunlight through a process called biophotolysis, using the enzyme hydrogenase.
- Microbes also play a role in petroleum formation, oil-spill cleanup, and enhanced recovery of petroleum, helping in sustainable energy management.
Key Points: Types of Biocontrol Agents
| Category | Biocontrol Agent | Target / Use |
|---|---|---|
| Insects | Ladybird beetle | Controls aphids |
| Insects | Dragonfly | Controls mosquitoes |
| Viruses | Baculoviruses (NPV) | Control insect pests like bollworm |
| Bacteria | Bacillus thuringiensis | Controls insect pests and mosquito larvae |
| Bacteria | Agrobacterium radiobacter (K-84) | Controls crown gall disease |
| Bacteria | Pseudomonas sp. | Controls fungal disease (damping off) |
| Fungi | Trichoderma sp. | Controls many plant diseases |
| Fungi | Beauveria, Metarhizium, Verticillium | Control insect pests |
| Fungi | Aschersonia aleyrodis | Controls whiteflies |
Key Points: Microbes as Biofertilizers
- Biofertilizers are living micro-organisms that improve soil fertility by increasing the availability of nutrients to plants.
- They are eco-friendly alternatives to chemical fertilizers, which degrade soil quality and reduce microbial life.
- Nitrogen-fixing microbes such as Rhizobium, Azotobacter, Azospirillum, and Frankia convert atmospheric nitrogen into usable forms.
- Legume–Rhizobium symbiosis forms root nodules that fix large amounts of nitrogen and enrich the soil for subsequent crops.
- Azolla–Anabaena symbiosis and cyanobacteria are widely used in paddy fields and significantly increase rice yield.
- Mycorrhiza (fungus–root association) enhances absorption of phosphorus and other minerals and protects plants from pathogens.
- Phosphate-solubilizing bacteria and fungi convert insoluble phosphates into forms available to plants.
- Biofertilizers improve crop yield, reduce fertilizer requirement, and help in sustainable agriculture and soil conservation.
Important Questions [10]
- Home-made fruit juices are turbid, while the bottled ,fruit juices purchased from the market are clear. Give a reason for this difference.
- Give the biological name of the following: The microbe used to produce Swiss cheese.
- Give the biological name of the following: A symbiotic nitrogen-fixing bacterium found in root nodules.
- Which one of the following factors is responsible for activation of protoxin into active Bt toxin of Bacillus thuringiensis?
- Expand DDT
- Give the biological name of the following: The mould from which penicillin is obtained.
- Give the biological name of the following: The microbe used to control insect larvae growing on cotton.
- Give the biological name of the following: The fungus that is being developed as a bio-control agent.
- Give Reasons for the Following: Nitrogenous Fertilizers Are Not Applied in Fields Where Leguminous Crops Grow.
- Why are the spores of Bacillus thuringiensis used as bioinsecticide?
