ISSN:
1432-072X
Keywords:
Methanogenic bacteria
;
Methanofuran
;
Coenzyme M
;
Tetrahydromethanopterin
;
Coenzyme F420
;
Disulfide reductase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The activities of formylmethanofuran dehydrogenase, methylenetetrahydromethanopterin dehydrogenase, methylenetetrahydromethanopterin reductase, and heterodisulfide reductase were tested in cell extracts of 10 different methanogenic bacteria grown on H2/CO2 or on other methanogenic substrates. The four activities were found in all the organisms investigated: Methanobacterium thermoautotrophicum,M. wolfei, Methanobrevibacter arboriphilus, Methanosphaera stadtmanae, Methanosarcina barkeri (strains Fusaro and MS), Methanothrix soehngenii, Methanospirillum hungatei, Methanogenium organophilum, and Methanococcus voltae. Cell extracts of H2/CO2 grown M. barkeri and of methanol grown M. barkeri showed the same specific activities suggesting that the four enzymes are of equal importance in CO2 reduction to methane and in methanol disproportionation to CO2 and CH4. In contrast, cell extracts of acetate grown M. barkeri exhibited much lower activities of formylmethanofuran dehydrogenase and methylenetetrahydromethanopterin dehydrogenase suggesting that these two enzymes are not involved in methanogenesis from acetate. In M. stadtmanae, which grows on H2 and methanol, only heterodisulfide reductase was detected in activities sufficient to account for the in vivo methane formation rate. This finding is consistent with the view that the three other oxidoreductases are not required for methanol reduction to methane with H2.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00244962
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