Cellular fatty acid composition of 8 species of sulfate-reducing bacteria was determined.
Five species of
Desulfovibrio, non-sporulating sulfate-reducing bacteria, were divided into two major groups based on the composition. One group contained unsaturated branched-chain fatty acids as major fatty acids and the other did not.
Desulfovibrio vulgaris, Desulfovibrio desulfricans, and
Desulfovibrio salexigens in the former group contained
iso-C
15:0, C
16:0, and
iso-C
17:1 as the most abundant acids. In
Desulfovibrio africanus which was also classified into the former group, the relative amount of each acid was largely different from that in the 3 species mentioned above. The most abundant acid was C
18:1Δ11 and
iso-C
16:1,
iso-C
17:1, and
anteiso-C
17:1 were detected as the next most abundant acids. In contrast,
Desulfovibrio gigas which belonged to the latter group contained
anteiso-C
15:0 and
iso-C
14:0 as major acids and the overall profile of the composition was remarkably different from the 4 species in the former group.
The cellular fatty acid composition in 3 species of
Desulfotomaculum, sporulating sulfate-reducing bacteria, was different from that in the
Desulfovibrio species. The 3 species were divided into two major groups.
Desulfotomaculum nigrificans contained odd-numbered saturated branched-chain fatty acids (
iso-C
15:0 and
anteiso-C
15:0) as major acids, and in
Desulfotomaculum orientis and
Desulfotomaculum ruminis, even numbered straight-chain fatty acids (C
16:0 and C
16:1) were the major acids.
Heterogeneity in the cellular fatty acid composition in both of non-sporulating and sporulating species suggests taxonomical confusion in the sulfate-reducing bacteria.
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