Highly selective and industrial relevant lactic acid production from cheese whey permeate in non-sterile conditions. Cheese whey permeate LA fermentation

Cheese whey permeate (CWP) is a low value industrial side stream with limited applications, that can be used to produce lactic acid (LA). LA has several applications in the food and pharmaceutical industry and can be used as a substrate for microbial protein or carboxylate production. Conventionally, optically pure LA (i.e. L(+)-LA or D(-)-LA) is produced using pure microbial cultures characterized by high energy and investment costs. To avoid sterilisation, non-axenic conditions can be employed. In this study, we evaluated different operational parameters (temperature, pH and hydraulic retention time (HRT)) in a continuous stirred tank reactor (CSTR) to explore the potential of non-sterile LA fermentation. The LA fermentations were evaluated upon LA productivity, yield, selectivity and optical purity.