Extracellular Lipids of Cladosporium ( Amorphotheca ) resinae Growth on Glucose or on n -Alkanes

Abstract

Cladosporium ( Amorphotheca ) resinae was grown in shake culture on glucose, n -dodecane, or n -hexadecane. Growth was most rapid on glucose, and more acid accumulated in the medium than in n -alkane-grown cultures. Neutral lipid was the major lipid fraction and triglycerides were the only extracellular neutral lipids detected. Dodecanoic (lauric) acid was the predominant fatty acid (>60%) in neutral lipids from all three media, with lesser amounts of tetradecanoic, hexadecanoic, and octadecanoic acids. Extracellular phospholipids identified were phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, and cardiolipin or a cardiolipin-like compound. Phospholipids from all three media contained dodecanoic acid as their principle fatty acid. Dodecanoic acid was the only extracellular free fatty acid detected. Glucose medium contained acetic, glyoxylic, and glycolic acids and an unidentified organic acid which may contribute to the lower pH in cultures after growth on glucose. In all classes of extracellular lipids the fatty acids do not correspond to the fatty acids previously determined to be associated with cellular lipids. Moreover, the fatty acids of extracellular lipids do not reflect the chain length of the n -alkane growth substrate.