Methane-Producing Bacteria

bacteria capable of producing energy through the reduction of CO₂ to methane (CO₂ + 4H₂ → CH₄ + 2H₂O). Certain methane-producing bacteria are capable of fermenting methyl alcohol or acetic acid (CH₃COOH → CH₄ + CO₂), forming methane from the carbon of the methyl group. No other substances are used directly.

All methane-producing bacteria are strict anaerobes and nonsporiferous, and all are difficult to isolate in pure culture. The representatives of Methanobacterium are bacilli that sometimes form short chains; those of the genus Methanococcus have spherical cells that grow separately; the cocci of Methanosarcina form cubic packets.

Methane-producing bacteria inhabit soil, the slime of ponds and lakes, and marshes (the bubbles of “marsh gas” that rise to the surface of the water consist of methane). Representatives of the group are also found in considerable numbers in methane tanks, which are used in the anaerobic mineralization of organic sewage. Methane-producing bacteria multiply intensively in the rumen of ruminants, where the decomposition of vegetable fodder by the microflora results in the formation of organic acids, CO₂, H₂, and CH₄. Methane-producing bacteria are capable of synthesizing vitamin Bi₂, which can be obtained by cultivating the organisms on waste grains in fermenting works.