Hydrocarbons, free fatty acids, and amino acids of sclerotia of Sclerotinia sclerotiorum.

Abstract

Sclerotia of Sclerotinia sclerotiorum (Lib.) D By. were obtained from commercial pea-and bean-cleaning operations or grown on potato-dextrose agar and synthetic glucose-and sucrose-salts agar media. The crude fat (ether extract) content of sclerotia varied from 0.8 to 1.5%. Extraction and fractionation of the lipids followed by gas chromatographic analysis showed that sclerotia from pea cleanings contained one predominant hydrocarbon which was absent from sclerotia produced in the laboratory. Sclerotia from natural sources and grown in the laboratory contained a similar distribution of C18 unsaturated free fatty acids, however, quantitative differences were noted. Palmitic, oleic and linoleic were the major free fatty acids of the laboratory-grown sclerotia while a high proportion of linoleic acid was also found in sclerotia from natural sources. Sclerotia were fractionated into water-soluble and water-insoluble fractions. After acid hydrolysis of the waterinsoluble fraction, both fractions were analyzed for amino acids. Twenty-one compounds, including 2 unknowns, were detected in the soluble fraction. The hydrolyzates contained 19 amino acids, including the same 2 unknowns. Two compounds tentatively identified as ornithine and γ-aminobutyric acid were found only in the water-soluble fraction. The relative amino acid composition of the water-insoluble fraction of sclerotia from various sources was fairly constant but the arginine content decreased on the synthetic media.