Anaerobic digestion, commercial additives

The simplest alkane (that is, with n = 1) is methane (CH4), which, in addition to several natural sources, is a natural product of the anaerobic bacterial decomposition of vegetable matter under water. Because it was first collected in marshes, methane became known as marsh gas. A rather improbable but proven source of methane is termites. When these voracious insects consume wood, the microorganisms that inhabit their digestive system break down cellulose (the major component of wood) into methane, carbon dioxide, and other compounds. It is estimated that termites produce 170 million tons of methane annually Methane is also produced in some sewage treattnent processes. Commercially, methane is obtained from natural gas. 

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