A Simple Procedure for Detecting the Presence of Cyclopropane Fatty Acids in Bacterial Lipids

Four gram-negative bacterial species, includingEscherichia coli strain B,Serratia marcescens, Pseudomonas fluorescens , andVibrio cholerae (comma ) strain NIH 41, were investigated for fatty acid content by gas-liquid chromatography involving a preparatory technique which facilitated detection of cyclopropane fatty acids. Methyl esters of fatty acids were subjected to mild catalytic hydrogenation to eliminate unsaturates. Hydrogenation was followed by bromination which removed cyclopropane acids from chromatographic profile patterns. Lactobacillic acid (cis -11,12-methyleneoctanoate) andcis -9,10-methylenehexadecanoate, previously reported in lipids ofE. coli andS. marcescens , were found in small amounts inP. fluorescens but were not detected inV. cholerae .