Fatty-acid Metabolism of Mannosylerythritol Lipids as Biosurfactants Produced by Candida antarctica

The fatty acid metabolism of extracellular glycolipids, mannosylerythritol lipids produced by the yeast Candida antarctica T-34 and used as biosurfactants, was examined using individual fatty compounds of various chain lengths (from C12 to C18) as the sole source of carbon. The fatty acids in the glycolipids in all cases consisted of medium-chain fatty acids such as C8, C10 and C12 acids for even numbered substrates and C7, C9 and C11 acids for odd-numbered substrates. trans-3 and cis-4 decenoic acids were the major components found on using methyl linoleate. The fatty-acid compositions of triacylglycerols, major cellular lipids in yeast, significantly depended on substrate chain length.The biosynthetic routes of fatty acids are thus shown to differclearly for extracellular glycolipids and cellular lipids. Most medium-chain fatty acids in the former case were β-oxidation intermediates synthesized directly from the substrates by a “chain-shortening pathway” such as the mammalian peroxisomal β-oxidation system and then incorporated into the glycolipid fraction. This paper presents the first evidence for the participation of the “chain-shortening pathway” in the biosynthesis of glycolipids.