Microbes in Production of Biogas - Practice Questions & MCQ

• Biogas is a mixture of gases (containing predominantly methane) produced by the microbial activity and which may be used as fuel. 
• The microbes produce different types of gaseous end-products during growth and metabolism.
• The type of the gas produced depends upon the microbes and the organic substrates they utilise.
• Certain bacteria, which grow anaerobically on cellulosic material, produce large amount of methane along with CO2 and H2. 
• These bacteria are collectively called methanogens, and one such common bacterium is Methanobacterium.
• These bacteria are commonly found in the anaerobic sludge during sewage treatment. 
• These bacteria are also present in the rumen (a part of stomach) of cattle. 
• A lot of cellulosic material present in the food of cattle is also present in the rumen. 
• In rumen, these bacteria help in the breakdown of cellulose and play an important role in the nutrition of cattle. 
• Thus, the excreta (dung) of cattle, commonly called gobar, is rich in these bacteria. 
• Dung can be used for generation of biogas, commonly called gobar gas.

Biogas Plant

• The biogas plant consists of a concrete tank (10-15 feet deep) in which bio-wastes are collected and a slurry of dung is fed.
• A floating cover is placed over the slurry, which keeps on rising as the gas is produced in the tank due to the microbial activity. 
• The biogas plant has an outlet, which is connected to a pipe to supply biogas to nearby houses. 
• The spent slurry is removed through another outlet and may be used as fertiliser. 
• Cattle dung is available in large quantities in rural areas where cattle are used for a variety of purposes. 
• So biogas plants are more after build in rural areas. 
• The biogas thus produced is used for cooking and lighting. 
• The technology of biogas production was developed in India mainly due to the efforts of Indian Agricultural Research Institute (IARI) and Khadi and Village Industries Commission (KVIC).