Influence of sulfide compounds on the metabolism of Methanobacterium strain AZ.

Various organic sulfides and inorganic sulfide were studied in respect to their effect on growth and methane production of Methanobacterium strain AZ. In mineral, sulfide-free medium, cysteine regulated the specific rate of methane production (optimum concentration = 5-10(-4) mole/1). A supplement of sulfide (10(-4) mole/1) caused an additional stimulation. Coenzyme M** or glutathione could be substituted for cysteine when sulfide was present. Growth was stimulated by CoM and glutathione to the same extent as with cysteine in sulfide-containing media. The concentration of sulfide in cysteine-containing media affected the excretion of amino acids.