BIOCHEMISTRY OF LONG-CHAIN NONISOPRENOID HYDROCARBONS .I. CHARACTERIZATION OF HYDROCARBONS OF SARCINA LUTEA AND ISOLATION OF POSSIBLE INTERMEDIATES OF BIOSYNTHESIS

The hydrocarbons of an adequately identified strain of Sarcina lutea were characterized by a combination of thin-layer and gas-liquid partition chromatography, infrared spectroscopy, and oxidative cleavage of the double bonds. The major hydrocarbon fractions had 27, 28, and 29 carbons (18.4, 12.7, and 65.3% of the total, respectively) and the proportions did not vary greatly with the age of the culture. In 48-hr cultures, 90% of the hydrocarbons were monounsaturated and the percentage decreased as the cells continued into stationary phase. Only hydrocarbons with cis configuration of the double bond were detected. Chromatographic analysis of the hydrocarbons and the fatty acids produced by oxidation of the double bonds was used to establish the detailed structure of the three major fractions. A large percentage of these had branched methyl groups in either the iso or anteiso configuration on both terminae and the double bonds were near the center of the primary chain. This is consistent with biosynthesis by head-to-head condensation of two fatty acids. Also, because 36% of the fatty acids obtained by oxidation of the double bonds of the hydrocarbons were found to be a C-14 anteiso fatty acid which was not found in the lipid fatty acids, decarboxylation of one of the fatty acids during condensation probably occurs. In further support for this biosynthetic mechanism, long-chain ketones and secondary alcohols that would be expected as intermediates in such a pathway were isolated from the nonsaponifiable lipids of S. lutea. © 1969, American Chemical Society. All rights reserved.