Purification of biodiesel-derived crude glycerol by acidification to be used as a carbon source for microbial oil production by oleaginous yeast Pseudozyma parantarctica CHC28

This research aimed to apply the acidification method to remove impurities from biodiesel-derived crude glycerol (BCG) and investigate the potential of purified BCG (PBCG) to be used as a carbon source for microbial oil production by oleaginous yeast Pseudozyma parantarctica CHC28. The optimum purifying conditions of BCG were pretreated with hydrochloric acid at a pH of 1.71. The PBCG concentration was 469.52 g/L under optimized conditions. The batch fermentation was studied using a nitrogen-limited medium containing PBCG (PBCG-medium). The PBCG-medium with 50 g of PBCG per liter provided the maximum biomass and oil concentration of 11.10 g/L and 4.07 g/L, respectively. The oil accumulation was approximately 45%. The long-chain fatty acids C16–C18 were the main compositions, which accounted for over 85%. These results suggested that the conversion of PBCG into microbial oil was an interesting direction to produce microbial oil. It was also a remarkable solution to add value to the by-products from biodiesel production. The mathematical model was demonstrated to describe satisfactorily the yeast growth and microbial oil production profile achieved in media containing pure glycerol and PBCG as carbon sources.