Purification and characterization of C28–55 fatty acids from Mycobacterium smegmatis

Abstract

The nonmycolic C₁₆ to C₅₅ fatty acids obtained from Mycobacterium smegmatis ATCC 356 by saponification were enriched with respect to the C₂₈ to C₅₅ acids by successive chromatography on silicic acid and Sephadex LH-20 columns. These partially purified fatty acids were then derivatized to the p-bromophenacyl ester and further fractionated by argentation thin-layer chromatography and reverse-phase high-performance liquid chromatography into their individual components.The esters were characterized by electron impact mass spectrometry. Two structural series of C_28:1 to C_42:1 and C_45:2 to C_55:2 fatty acids were identified as possible precursors of the monoenyl and dienyl mycolic acids, respectively. These acids were structurally related to the α-alkylhydroxyl group of the corresponding mycolic acid. The results suggest that these C₂₈ to C₅₅ fatty acids (meromycolic acids) of M. smegmatis might be precursors of mycolic acids.