Separation of unsaturated fatty-acid producing fungi from Sargassum and analysis of fatty acid composition

Abstract:

[Background] A special extracting raw material with low cost is extremely urgent, as the expense of extracting unsaturated fatty acids from fish and crops is growing high. The particularity of ocean environment results in a rich and unique microbial resource, which have been regarded as a new strategy for obtaining unsaturated fatty acids. [Objective] The aim was to isolate oil-producing fungi from Scagassum collected from Xuwen Port, Zhanjiang, Guangdong Province, and analyze its fatty acid composition by gas chromatography (GC). [Methods] The selective plating medium and method of Sudan Black B staining were used to screen high-yield oil-producing fungi. The target strain was identified by morphological and culture characteristics and analysis of ITS sequences. GC was used to determine the composition and content of the lipids which were extracted by chloroform-methanol. [Results] A total of 7 oil-producing fungal strains were screened, among which strain A17 was the high-yield oil-producing fungus with larger lipochondrion. The analysis of morphology and molecular identification of ITS sequence showed that the strain A17 was Fusarium incarnatum. The oil extracted from the strain A17 accounted for 24.75% of the cell dry weight, and unsaturated fatty acid accounted for 60.76% of the total oil content, which oleic acid and linoleic acid were 32.80% and 26.20 %, respectively. [Conclusion] This study may provide a theoretical base for the development of oil-producing strains in Scagassum.

Key words:Sargassum, unsaturated fatty acid, fungi, isolation, Gas chromatography (GC)