Changes in Cellular Fatty Acid Composition of Cephalosporium acremonium during Cephalosporin C Production

Abstract

Cephalosporium acremonium was cultivated in fermentation medium containing sucrose or methyl oleate as a carbon source for cephalosporin C production. The level of antibiotic production was 48 g of cephalosporin C per liter under optimum conditions when methyl oleate was used. The C 18:1 (oleic acid) methyl ester appeared to be utilized faster than the C 18:2 (linoleic acid) methyl ester in fermentation broth. Physiological characteristics of C. acremonium were investigated by determining the fatty acid composition of the total cellular free lipid. Significant changes in cellular fatty acid composition occurred during inoculum cultivation and fermentation. The percentage of C 18:1 increased from 19.1 to 38.5%, but the percentage of C 18:2 decreased from 56.7 to 36.1%, and there was an increase in pH during inoculum cultivation. The cellular fatty acid composition of C. acremonium grown in fermentation medium containing methyl oleate (methyl oleate medium) was significantly different from that in fermentation medium containing sucrose (sucrose medium). The major fatty acids detected were C 16:0 (palmitic acid), C 18:1 , and C 18:2 . In methyl oleate medium, the ratio of C 18:1 to C 18:2 increased from 0.34 to 1.37, while the cell morphology changed from hyphae to arthrospores and conidia. In contrast, in sucrose medium, the ratio of C 18:1 to C 18:2 decreased from 0.70 to 0.43, and most of the cells remained hyphal at the end of fermentation. We observed that hyphae contained a higher proportion of C 18:2 but arthrospores and conidia contained a higher proportion of C 18:1 .