Elongation of lauric and myristic acid and desaturation of stearic acid in Aspergillus niger

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Authors
Shellenbarger, Rex L., 1948-
Advisor
Bennett, Alice S.
Issue Date
1973
Keyword
Degree
Thesis (M.S.)--Ball State University, 1973.
Department
Other Identifiers
Abstract

The elongation and desaturation of fatty acids was investigated by studying the fate of 1-14C lauric, myristic, and stearic acids added to submerged cultures of Aspergillus niger. The mycelium produced oleic and linoleio acids from 1-14C lauric and 1-14C steario acids and to only a slight extent from 1-14C myristic acid. Stearic acid was the principal labeled saturated fatty acid produced when laurio acid was the substrate; both palmitic and steario acids were produced in reduced amounts from myristic acid. Myristic acid has been reported to be a poor precursor for long chain fatty acids in Penicillium chrysogenum and Torulopsos bombicoli well. The absence of label in fatty acids shorter than the added substrates indicated that oxidation followed by do novo synthesis did not occur. Pariodate-permanganate oxidation data verified that do novo synthesis did not occur.When either 1-14C lauric acid or 1-14C myristic acid was the substrate, Schmidt decarboxylation data of the saturated fatty acids longer that the substrate indicated that the terminal acetate unit of the substrate was removed and used to elongate palmitio acid to steario acid. The rapid incorporation. of label into long chain fatty acids supports this conclusion. When 1- 4C steario acid was the substrate, decarboxylation data of the saturated fatty acids longer than stearicindicated that the terminal acetate unit of the substrate was removed and used to produce fatty acids with chain lengths longer than stearic acid.Ball State UniversityMuncie, IN 47306

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