Characterization of novel methyl-branched chain fatty acids from a halophilic Bacillus species.

The 4-methylated fatty acids 4,9-dimethyldecanoic, 4,11-dimethyldodecanoic, 4,10-dimethyldodecanoic, and 4,13-dimethyltetradecanoic acid as well as the 2-methylated fatty acids 2,13-dimethyltetradecanoic and 2,12-dimethyltetradecanoic acid were identified for the first time in nature in the halophilic bacterium Bacillus sp. isolated from the salt pans of Burgas in Bulgaria. The principal fatty acids in this bacterium were a series of iso-anteiso fatty acids with chain lengths between C11 and C19, but an interesting series of linear alkylbenzene fatty acids with chain lengths between C10 and C14, such as 12-phenyldodecanoic acid, were also identified. The novel 4-methylated fatty acids were characterized using a combination of GC-MS and chemical transformations such as N-acylpyrrolidide derivatization. The 2-methylated fatty acids were also identified by GC-MS and gas chromatographic coelution with synthetic samples. The novel methyl-branched fatty acids probably originated from the selective incorporation of methylmalonyl-CoA by one of the fatty acid-synthesizing enzymes of the bacterium.

Two novel iso-branched octadecenoic acids from a Micrococcus species.

The novel fatty acids 16-methyl-6(Z)-heptadecenoic acid and 16-methyl-8(Z)-heptadecenoic acid were identified for the first time in nature in a species of the bacterium Micrococcus isolated from Lake Pomorie in Bulgaria. The principal fatty acids in this bacterium were a series of iso-anteiso fatty acids with chain lengths between C(14) and C(24), while the most interesting series of monounsaturated fatty acids was a family of Delta(6) fatty acids with chain lengths between C(14) and C(17). The novel compounds were characterized using a combination of GC-MS and chemical transformations, such as dimethyl disulfide derivatization and catalytic hydrogenation. The results established for the first time a bacterial origin for some of these Delta(6) fatty acids.

Unusual lipid composition of a Bacillus sp. isolated from Lake Pomorie in Bulgaria.

The lipid composition of a Bacillus sp., isolated from Lake Pomorie in Bulgaria, was unusual and consisted of 26 different fatty acids between C12 and C26, with anteiso C15-C17 saturated fatty acids predominating. The furan fatty acid, 10,13-epoxy-11-methyloctadeca-10,12-dienoic acid, was also identified, a new finding for this genus. The hydrocarbons consisted of 30 different monounsaturated hydrocarbons, between C25 and C30, with the iso-iso, iso-anteiso, anteiso-anteiso, iso-normal, and anteiso-normal methyl branching for odd-numbered chains, and the iso-iso, iso-anteiso, iso-normal, and anteiso-normal methyl branching for even-numbered chains. The double bond positions in these hydrocarbons were determined by dimethyl disulfide derivatization followed by GC-MS, and the double-bond cis configuration was confirmed by infrared spectroscopy. Some previously unknown hydrocarbons in bacteria, such as (Z)-3,21-dimethyl-9-tricosene, (Z)-3,21-dimethyl-10-tricosene, (Z)-2,24-dimethyl-11-pentacosene, and (Z)-2,25-dimethyl-13-hexacosene were identified. Sterols were detected and were based on the sitosterol nucleus.