Abstract:Various substrates feeding strategies for cephalosporin C (CPC) efficient production by Cephalosporins acremonium were studied and conducted in a 7 L fermentor. A novel ammonium sulfate feeding strategy in couple with soybean oil addition was proposed. With this strategy, NH4+ concentration in fermentation broth could be stably maintained in a range of 3?6 g/L throughout fermentation period, simultaneously satisfying the demands on nitrogen and sulfur sources for cells growth and CPC synthesis, promoting Cephalosporins acremonium hyphal split, and creating the prerequisite for the subsequent CPC efficient production. Based on the novel ammonium sulfate feeding strategy, perform-ance of the subsequent CPC fermentations with different soybean oil feeding strategies, namely inter-mittent, constant rate and automatic DO-Stat feeding was compared. Feeding ammonium sulfate in couple with the soybean oil feeding in a manner of DO-Stat+oxygen-enriched air aeration at late fer-mentation phase could control carbon source concentration and DO at adequate levels, ensuring effi-cient CPC synthesis in a way of high CPC concentration and low by-product accumulation. With this combinational feeding strategy, final CPC concentration and CPC yield could reach 35.77 g/L and 13.3%, respectively, the major by-product, de-acetoxycephalosporin (DAOC) and DAOC/CPC were only 0.178 g/L and 0.5%.
