CCVII. HYDROGENASE. III. THE BACTERIAL FORMATION OF METHANE BY THE REDUCTION OF ONE-CARBON COMPOUNDS BY MOLECULAR HYDROGEN

THE production of methane from a 1-carbon compound was first observed by Sohngen in his classical work on methane formation from fatty acids [Sohngen, 1910], calcium formate being quantitatively decomposed to give methane and calcium carbonate. The same culture also effected the reduction of carbon dioxide. It is important to notice that Sohngen worked with mixed cultures which produced methane also from the higher fatty acids. More recently Fischer et al. [1931] have obtained from mud a culture (not claimed by them to be pure) which reduces carbon monoxide to methane, the reaction being accelerated by various colloids. These authors suggest that carbon dioxide is an intermediate product, some evidence being adduced for the occurrence of the reaction CO + H20 + CO2 + H2.