Methanosarcina barkeri, methane formation

The acetyl-coenzyme A decarbonylase synthase complex contains five polypeptide sub-nnits and in acetate-degrading methanotrophs, such as Methanosarcina barkeri and M. thermophila, catalyzes the formation of methane and COj from acetyl-CoA ... 

Hippe H, D Caspari, K Fiebig, G Gottschalk (1979) Utilization of trimethylamine and other N-methyl compounds for growth and methane formation by Methanosarcina barkeri. Proc Natl Acad Sci USA 76 494-498. 

It was shown later that ATP synthesis can be coupled to methanogenesis at very low A/iH values (—90 to —lOOmV) [103] Proton potentials of defined magnitude, adjusted with K gradient in the presence of valinomycin, were applied to cells of Methanosarcina barkeri and Methanobacterium thermoautotrophicum, and the ATP pool and the rates of methane formation from Hz/methanol and from Hz/COz were followed as a function of... 

CO2 reduction to formyl-MFR in cell extracts. Cell extracts of Methanobacterium thermoautotrophicum catalyze the formation of formyl-MFR from H2, CO2 and MFR. The rates of formation of formyl-MFR were stimulated by CH3-S-CoM [170,171] or CoM-S-S-HTP [172], suggesting that CO2 activation is coupled with the terminal steps of methane formation ( RPG effect [170], for literature see [173]). The mechanism of that coupling is far from clear. The heterodisulfide may act as an allosteric effector in the activation of low-potential electron carriers in electron flow from H2 to formyl-MFR [173]. It should be pointed out that the RPG effect was not observed in cell extracts of Methanosarcina barkeri[ 14],... 

To date only five species of methane bacteria have been obtained in pure culture. M. vanniellii (5), Methanohacterium ruminantium (7), Methanobacterium mobilis (28), and Methanobacterium formicicum (21) grow on formate and ferment H2. The last species also ferments CO. The methanogenic symbiont of M. omelianskii, probably a variety of M. formicicum (29) grows only on H2 (16). Methanosarcina barkeri is iso-... 

Methane formation from trimethylamine by Methanosarcina barkeri has been demonstrated (Hippe et al. 1979 Patterson and Hespell 1979), and the metabolically versatile organisms Methanococcoides methylutens (Sowers and Ferry 1983) and Methanolobus tindarius (Konig and Stetter 1982) that use methylamines and methanol for methane formation have been described. 

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