Statistical optimization and gamma irradiation on cephalosporin C production by Acremonium chrysogenum W42-I

Abstract

Most antibiotics now used in clinical practice are cephalosporins. Acremonium (A.) chrysogenum W42-I is an intermediate strain out of W42 strain improvement program whose productivity is above that of the wild-type strain to produce the broad-spectrum antibacterial cephalosporin C (CPC). As a result, fermentation process optimization is considered because it offers the ideal environment for strains to reach their full potential. Our research aimed to combine a rational design to regulate the fermentation process environment and culture media as well as to develop mutants with high productivity. Different media were tested to obtain maximum CPC production. To maximize the production of CPC, some environmental parameters were experimentally optimized via the Box-Behnken design used for response surface methodology (RSM). There were 17 tests conducted, and each experiment's reaction was recorded. Improvement of the CPC production was further achieved via mutagenesis using gamma radiation. Results revealed that a pH of 4, an incubation period of 4 days, and an inoculum size of 1% v/v using the optimized media (CPC2) were the optimum conditions for enhancing the CPC production by 4.43-fold. In addition, gamma irradiation further enhanced production to reach 3.46-fold using an optimum dose of 2 KGy. In conclusion, in comparison to initial production levels, CPC production increased 4.43-fold because of nutritional and environmental optimization. The mutant AC8 demonstrated a roughly 3.46-fold increase in activity against its parent type. Moreover, subsequent AC8 mutant culture demonstrated excellent genetic stability.