ISSN:
1432-072X
Keywords:
Methanogenic bacteria
;
Sulfate-reducing bacteria
;
Acetogenic bacteria
;
Corrinoid
;
Methane formation
;
Cobalt
;
Membrane cobamide
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract In Methanobacterium thermoautotrophicum a corrinoid-carrying membrane protein complex has been found, to which a tentative role in methane formation has been ascribed. To test this hypothesis representatives from different orders of methanogenic bacteria were examined for membrane-bound cobamides. These species differed in cell carbon precursor, in methane precursor, in occurrence of cytochromes and of the enzyme CO dehydrogenase, and in the systematic position (Methanobacteriales, Methanomicrobiales). All methanogenic bacteria contained cobamides in the membranes in amounts of about 60 nmol/g cell dry weight, in addition to different amounts of cobamides in the soluble cell fraction. The only central metabolic reaction obviously common to all of these methanogens was methyl coenzyme M reduction to CH4. It is concluded that the membrane corrinoid participates in this energy-conserving reaction. Sulfate-reducing and acetogenic bacteria were included in this survey. They contained different amounts of cobamides in the soluble cell fraction but not in the membrane, a possible exception being Acetobacterium woodii.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00429647
