Lipid composition of the phosphatidylcholine-producing bacterium Hyphomicrobium vulgare NP-160

The extractable lipids of the PC-producing, methylotrophic, budding bacterium Hyphomicrobium vulgare NP-160 grown in a mineral-salts medium containing methanol as the carbon source, were studied by chromatographic and spectrometric methods. They were found to be comprised of PC (35% of the total lipids), PDME (33%), PMME (1%), PE (9%), PG (10%), DPG (6%), and a non-phosphorus, ornithine-containing lipoamino acid, OL (6%). No low-polarity lipids, such as fatty acid esters of glycerol or of other alcohols, were detected. The sole fatty-acyl constituents of PDME and PMME were cis-octadec-11-enoic (cis-vaccenic) acid residues, whereas the other phospholipids contained, in addition, 1 to 5 mol % of MOA (lactobacillic acid) residues located predominantly at the sn-1 position of their glycerol residues. OL consisted of two molecular species, 2-N-[3'-(cis-octadec-11"-enoyloxy)octadecanoyl]-L- ornithine and 2-N-[3'-(cis-11", 12"-methyleneoctadecanoyloxy)octadecanoyl]-L-ornithine in the molar ratio 94:6. When the culture medium was devoid of phosphate, a threefold increase in OL together with a three-fold decrease in PE were observed, no significant changes in proportions of the remaining lipids occurring. The most striking feature of the lipid composition in this case was the presence of considerable amounts of fatty acid methyl esters, mainly methyl cis-vaccenate, along with minute amounts of wax esters.