Thermophilic fungi: III. The lipids ofHumicola grisea var.thermoidea

The lipids of the thermophilic fungusHumicola grisea var.thermoidea were qualitatively and quantitatively determined. The polar lipids consisted of 38.4-42.3% of the total lipids. The relative per cent phospholipids based upon the total phospholipids were as follows: phosphatidyl choline, 32.3-33.7%; phosphatidic acid, 24.5-31.7%; phosphatidyl ethanolamine, 15.8-20.9%; phosphatidyl inositol, 12.5-13.0%; phosphatidyl serine, 2.3-5.4%; and diphosphatidyl glycerol, 3.9-4.0%. The relatively high concentration of phosphatidic acid may be characteristic of fungi grown at elevated temperatures. Several sterol glycosides (3.1-6.0%) were present in the polar lipids. The neutral lipids consist of triglycerides, 28.6-36.0%; free fatty acids, 5.3-13.5%; sterols, 11.4-13.9%; sterol esters, 1.8-3.0%; and diglycerides, 2.2-3.4%. The sterols and derivatives comprise an unusually large fraction of the total lipids (16.3-22.9%) suggesting a role in thermostability.