Production of lactic acid by Enterococcus faecalis on waste glycerol from biodiesel production

Abstract

Waste glycerol from biodiesel production is a valuable raw material that has been used to produce valuable microbial metabolites. In this work, the possibility of microbial utilization of waste glycerol obtained as a by-product in biodiesel production from sunflower and rapeseed oil by the lactic acid bacterium Enterococcus faecalis MK3-10A on a laboratory level was studied. For comparison, pure glycerol and glucose were used as carbon sources. The kinetics of the microbial biomass growth, the carbon source utilization, and the lactic acid production were monitored. The bacterium E. faecalis MK3-10A better grew in the media with glucose or pure glycerol as a carbon source, but the lactic acid production rate was the highest (14.6 mg/(ml/day)) in the medium with waste glycerol from the sunflower oil-based biodiesel production. Therefore, this waste glycerol might be a promising carbon source for lactic acidbacteria cultivation and lactic acid production.