Fatty acid composition and primer specificity of de novo fatty acid synthetase in Bacillus globispores, Bacillus insolitus, and Bacillus psychrophilus

The fatty acid compositions of three psychrophilic species of Bacillus were determined by gas--liquid chromatography. The proportions of straight-chain fatty acids, branched-chain fatty acids, and unsaturated fatty acids were found to be 13.3, 86.7, and 26.1% of the total cellular fatty acids for Bacillus globispores, 36.6, 63.4, and 25.1% for Bacillus insolitus, and 6.9, 93.1, and 18.4% for Bacillus psychrophilus, respectively. In all three organisms the de novo fatty acid synthetase specificity towards acyl-CoA primers was butyryl-CoA greater than propionyl-CoA much greater than acetyl-CoA. This shows that B. insolitus, which has an unusually large proportion of straight-chain fatty acids for Bacillus, does not possess a different de novo fatty acid synthetase than the other two organisms. Therefore, the greater proportion of straight-chain fatty acids in B. insolitus may be explained by a large supply of straight-chain primer.