Semi-continuous production of 2-keto-gluconic acid by Pseudomonas fluorescens AR4 from rice starch hydrolysate

► We compare the fermentation characteristic of 2KGA in the batch model. ► We optimize the processing parameters of 2KGA semicontinuous fermentation production. ► The strain Pseudomonas fluorescens AR4 is a potent industrial 2KGA producer. ► Semicontinuous fermentation improves the efficiency of 2KGA production.