Question

Methanogenic bacteria are not found in

• A. rumen of cattle
• B. gobar gas plant
• C. bottom of water-logged paddy fields
• D. activated sludge

Answer 1

The Correct Option is D

Methanogens are strict anaerobes. Nutritionally they are "autotrophs" which obtain both energy and carbon from decomposition products. They occur in marshy areas where they convert formic acid and carbon dioxide into methane with the help of hydrogen. This capability is commercially exploited in the production of methane and fuel gas inside gobar gas plants, e.g., Methanobacterium, Methanococcus. Some of the methanogen archaebacteria live as symbionts ( e.g., Methanobacterium) inside rumen or first chamber in the stomach of herbivorous animals that chew their cud (ruminants, e.g., cow, buffalo). These archaebacteria are helpful to the ruminants in fermentation of cellulose. The ; warm, water logged soil of paddies provides ideal condition for methanogenesis and though some of the methane produced is usually oxidised by methanotrophs in the shallow overlying area vast majority is released into atmosphere. Methanogenic bacteria are not found in activated sludge instead activated sludge contains aerobic microorganisms.