Bioconversion of potato-processing wastes into an industrially-important chemical lactic acid

Lactic acid (LA) is an important biomolecule applied in food, pharmaceutical and chemical areas, mainly to produce biodegradable polymers, such as poly–lactic acid (PLA). In this work, an efficient fermentative process for LA production was developed using potato processing waste (PPW) hydrolysate with Lactobacillus pentosus. After optimization and kinetics studies, LA production reached 150 g/L with a productivity of 1.6 g/L.h in Erlenmeyer flasks. LA production was also conducted in STR where 110 g/L were reached with a productivity of 2.4 g/L.h. LA recovery consisted of a clarification step, with powdered activated carbon, with further precipitation at low temperature and acidification of calcium lactate for conversion to LA. The process was effective for contaminants' removal and clarification, and LA concentration to 416 g/L. Good perspectives for LA production, recovery and clarification were observed. Future studies will be carried out for LA purification and polymerization for PLA synthesis.