Performance improvement of cephalosporin C fermentation by Acremonium chrysogenum with DO-Stat based strategy of co-feeding soybean oil and glucose

Abstract

Cephalosporin C (CPC) fermentation by Acremonium chrysogenum featured with two major problems: (1) high raw materials cost (low CPC yield from soybean oil) and (2) low oxygen transfer rate between gaseous/aqueous phases leading to low CPC productivity and quality instability of CPC fermentation product due to the accumulation of deacetoxycephalosporin C (DAOC). To solve the problems, in this study, we proposed a novel DO-Stat based co-substrates feeding strategy by simultaneously supplementing soybean oil and glucose, and testified the effectiveness of the strategy in a 7L bioreactor. The CPC fermentation performance were significantly improved when co-feeding soybean oil and glucose at a weight ratio of 1:0.7, as compared with those when feeding pure soybean oil: (1) final CPC concentration and yield reached higher levels of 37g/L and 23.5%, the increments were 46% and 82%, respectively; (2) oxygen transfer rate was largely improved, oil consumption rate and CPC productivity were enhanced by 31% and 136%, respectively; and (3) DO could be controlled at adequately high levels so that DAOC accumulation could be minimized and the quality of CPC fermentation product be ensured. The proposed strategy showed application potential in improving the economics of industrial CPC productions.