Branched fatty acids from Mycobacterium aurum.

New methyl-branched fatty acids were isolated from the lipids of Mycobacterium aurum, belonging to both saturated and non-saturated series. The most abundant component of the former series was identified as a C22-mycosanoic acid (2-L, 4-L-dimethyleicosanoic acid). The unsaturated fraction contained a mixture of 2-L, 4-L-dimethyl-11-eicosenoic acid and 2-L, 4-L-dimethyl-14-eicosenoic acid. The biosynthetic precursors of these, according to the hypothesis of elongation by propionate units, were found in the non-branched hexadecenoic fraction. The lipidic fraction containing mycosanoic acid was a partially acylated oligosaccharide devoid of sulfate or phosphate groups.