Lipids of Rhizopus arrhizus Fischer

Abstract
The lipids of Rhizopus arrhizus Fischer mycelia and sporangiospores were extracted, isolated, and separated by thin-layer, liquid, and gas chromatography. Structural confirmations of the compounds were made by a gas chromatographmass spectrometer combination. The n -heptane fraction contained squalene (1%) as a major hydrocarbon constituent. Other major lipid classes detected were free fatty acids, naturally occurring methyl esters of fatty acids, triglycerides, sterols, and polar lipids. The polar lipids (44.4%) were found in the highest concentrations, and the triglycerides (22.1%), sterols (16.7%), and free fatty acids (11.7%) were present in lesser concentrations. This is the first report of naturally occuring methyl esters of long-chain fatty acids being present in fungal mycelium. There appears to be a preference for incorporation of unsaturated acids into the complex lipids, with the exception of the triglycerides. The major saturated fatty acids in the mycelium were palmitic (C 16 ) and arachidic (C 20 ), whereas the major unsaturated acids were oleic (C 18:1 ) and linoleic (C 18:2 ), respectively.