Changes in the lipid composition of Paecilomyces persicinus P-10 M1 during growth and cephalosporin C production

Stimulation of cephalosporin C production in Acremonium chrysogenum M35 by glycerol

In this study, the effects of glycerol on cephalosporin C production by Acremonium chrysogenum M35 were evaluated. The addition of glycerol increased cephalosporin production by up to 12-fold. Glycerol caused the upregulation of the transcription of the isopenicillin synthase (pcbC) and transporter (cefT) genes in early exponential phase, and affected the cell morphology since hyphal fragments differentiated into arthrospores. These results indicate that glycerol effectively enhances cephalosporin C production via stimulation of cell differentiation.

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

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).