Fatty‐Acid Composition of Arthrobacter simplex Grown on Hydrocarbons

Fatty acids of Arthrobacter simplex cells grown on various n ‐alkanes or 1‐alkanes as the sole carbon ource have been investigated.1 The lipid pattern of the hydrocarbon‐grown cells was alsmost identical with that of the cells grown on the glucose‐yeast‐extract medium reported earlier. The phospholipids of both the cells consisted largely of cardiolipin and two types of phosphatiylglycerols. In one phosphatidyl‐glycerol, α‐hydroxy fatty acids, together with nonhydroxylated fatty acids, occurred as major fatty‐acid components. 2 Total fatty acids from the cells grown on 1‐octadecene were separated into several groups with different thin‐layer chromatographic characteristics, and analyzed by gas chromatography. C 16 , C 16:1 Δ 15 , C 17:1 Δ 9 , t ‐C 18 , C 18:1 Δ 9 , C 18:1 Δ 17 , t ‐C 19 , C 18:2 Δ 9,17 , t ‐C 19:1 Δ 17 , α‐OH‐C 16 and α‐OH‐C 16:1 Δ 15 acids were revealed to be presented as major fatty acids: ( t ) = 10‐methylstearic). Among them, C 18:2 Δ 9,17 and α‐OH‐C 16:1 Δ 15 acids were further characerized by use of mass spectrometry, and chemical oxidation and reduction. As the growth proceeded from the early phase to the stationary phase, it was noted that the content of odd‐numbered α‐hydroxy fatty acids increased markedly. 3 Fatty‐acid compositions of the cells grown on C 13 to C 19 alkanes and C 16 , C 18 and C 20 1‐alkenes were determined by gas chromatography. The results suggested that the hydrocarbongrown cells were capable of utilizing hydrocarbon skeletons without degradation for the synthesis of fatty acids. Furthermore, it was proposed that both the α and β oxidation of fatty acids operated equally substantially in A. simplex cells.