One of the applications of biotechnology is to get pest resistant plants Justify the statement with reference to Bt. cotton.

Bt ( Bacillus thuringenesis ) which is a bacterium. It produces Bt toxin. Bt toxin gene has been cloned from the Bacillus thuringenesis and been expressed in the plants to provide resistant insect hence there is thus it acts as a biopesticide. Some strains of Bacillus thuringenesis produce proteins that kill insects like lepidopterans,which is a tobacco budworm. Bt-cotton plant is a transgenic plant which produces an insecticide to bollworm. Bacillus thuringiensis can be characterised as the bacterium which has a Bt gene or Cry gene which is incorporated in the cotton plant through biotechnological methods and thus, it produces a crystalline product Bt. The product acts as a toxin in a situation when it gets ingested by the pests as it gets activated after reaching the alkaline gut of pests and creates pores in the intestine and kills the pests. The gene serves as the protection to GMO against budworm, bollworm, beetle, borer, etc. As a result of this application, the development of this plant has reduced the use of insecticides for protection against the pests.

Describe the role of Microbes in sewage treatment plant.

The treatment of sewage completes into three steps known as primary, secondary, and tertiary treatment. The microbe’s role comes in action in secondary treatment, also known as biological treatment. The biological treatment starts from aeration tank where primary effluent is poured and agitated so that the groups of microbes present in the effluent start consuming the organic matter present in the effluent. The microbes reduce the biological oxygen demand of water and purify it; after that, the secondary effluent is used as activated sludge for further treatment of primary effluent. The remaining part of the sediment microbe is transferred to anaerobic sludge digester, and the microbes anaerobically produce the methane, carbon dioxide, and hydrogen sulphide that is used as biogas. The effluent treated in secondary treatment further undergoes tertiary treatment to check its quality by chemical reaction test. The role of microbes in sewage treatment plants is as follows: The excess of nitrates and phosphates from fertilizers runs off into the ponds and streams. It leads to the formation of thick algal bloom, which is formed of blue green or green algae. Due to the biomass load, there is oxygen depletion, which leads to the suffocation of aquatic plants. The nutrients utilized during eutrophication is phosphate, followed by nitrate. The nutrients increase the growth and productivity of aquatic plants. It promotes the growth of marshy plants, which is finally converted into the land.

Mention the role of Methanobacterium in rumen of cattle.

Methanogens are the anaerobic bacteria present in the rumen of cattle. The cattle dung contains abundant methanogens, which decompose the cellulose substances through the process of fermentation. This dung is used in gobar gas plants to produce biogas. For example, Methanobacterium and Methanococcus .These microorganisms help in the digestion of cellulose and breakdown into glucose.