Formation of methane from serine by cell-free extracts of Methanobacillus omelianskii.

Precursors of methane formation by cell-free extracts of the obligat,c anacrobc, Methanobacillus omelianskii, include carbon dioxide, pyruvate, and serine (1). Recently, methylcobalamin, CH,-Bil (2-4), and N”-methyltetrahydrofolate, 5-CH3-H4-folate, have been shown to be substrates for cell-free methane formation (5). This communication is concerned with the role of tetrahydrofolate, H1-folate, derivatives in the transfer of carbon 3 of 3-*4C-L-serine to give 14CH4 by extracts of M. omelianskii and with the position of CH,-Blz in this metabolic pathway.