Valorisation of molasses by oleaginous yeasts for single cell oil (SCO) and carotenoids production

Abstract

Abstract Two oleaginous yeast strains (Rhodosporodium toruloides and Rhodotorula glutinis) were examined for valorisation of molasses by the production of single cell oil (SCO) and carotenoid pigments. In the batch culture studies, the volumetric productivities of R. toruloides and R. glutinis were 3.41 and 2.47 g L−1 d−1 in the molasses medium, compared to that of 1.75 and 1.47 g L−1 d−1, respectively in the glucose yeast extract mineral (GYM) medium, at 96 h. R. toruloides grown in molasses medium yielded a maximum of 0.295 g of biomass g−1 of substrate consumed; whereas R. glutinis produced 0.226 g of biomass g−1 of the substrate consumed. The lipid contents of R. toruloides and R. glutinis were 53% and 45% in the molasses medium, and 48% and 43% in the GYM medium, respectively. R. glutinis grown in the GYM medium recorded the maximum carotenoid yield (0.045%), volumetric carotenoid productivity (0.027 mg L−1 h−1), and cellular carotenoid content ( 448 μ g g − 1 of cell dry weight). A significant increase in biomass and lipid yield was observed in molasses grown yeast as compared to GYM medium. Oleic acid (C18:1) was the predominant fatty acid present in R. toruloides cultivated in GYM medium. This study confirmed the potential of molasses with low C/N ratio for enhanced lipid production.