Fed-batch gluconic acid production from Penicillium variabile P16 under different feeding strategies

Abstract: Penicillium variabile P16 is characterized by the ability to release high levels of glucose oxidase when grown in glucose-rich media converting, at the same time, glucose into gluconic acid. This work reports on gluconic acid production by the above strain grown in bench-top reactor under different strategies, traditional batch and fed-batch processes; Na2CO3 was substituted for CaCO3 as the buffering agent in order to prevent calcium gluconate precipitation over the mycelium that would limit oxygen uptake and, as a consequence, glucose conversion. Best results were obtained with an improved fed-batch process which, in addition to glucose, was continuously fed with nitrogen and minerals at a flow rate of 0.02mlmin−1: yield and total productivity were 99.4% and 2.02gh−1, respectively, and remained constant till the end of the fermentation (240h). [Copyright &y& Elsevier]