Degradation of long-chain n-alkanes by the yeast Candida maltosa

Abstract

The yeast Candida maltosa precultivated on liquid n-alkanes utilized different solid n-alkanes (especially C20−C25) in the presence of pristane as an organic phase with rates comparable to, or somewhat larger than, those of liquid n-alkanes. Analysis of cellular fatty acids indicated an assimilation of solid n-alkanes via monoterminal oxidation. The resulting fatty acids with substrate chain length were chain-shortened by C2 units down to an optimal range of chain length from C16 to C18 and incorporated into cellular, lipids directly or after desaturation. The intermediates of chain-shortening with numbers of carbon atoms higher than C18, as well as the unusually long-chain fatty acids of substrate chain length, were detected in trace amounts only. Even-carbon-numbered and odd-numbered fatty acids predominated in experiments with evenchain and odd-chain n-alkanes, respectively. Studies with cerulenin indicated that de novo synthesis of fatty acids was negligible. Oxidation of solid n-alkanes by the yeast C. maltosa yielded fatty acid patterns similar to those of cells grown on liquid n-alkanes.