Co-culture of an oleaginous yeast Rhodotorula glutinis and a microalga Chlorella vulgaris for biomass and lipid production using pure and crude glycerol as a sole carbon source

This study has shown that a co-culture of an oleaginous yeast Rhodotorula glutinis TISTR 5159 and a microalga Chlorella vulgaris var. vulgaris TISTR 8261 enhanced biomass and lipid production from glycerol. It is possible that the microalga may function as an oxygen producer in the co-culture and enhance the growth of yeast. The use of 3% pure glycerol as a carbon source and urea as a nitrogen source with a molar carbon-to-nitrogen (C/N) ratio of 32 gave the highest biomass and lipid production. These produced a 5.7-fold and 3.8-fold of biomass and lipid, respectively, compared to the initial unoptimized condition. The co-culture system was also applied to convert crude glycerol, a by-product from a biodiesel plant, to biomass and lipid. The lipid produced from the crude glycerol by the co-culture was mainly composed of palmitic acid (C16:0) 40.52% and oleic acid (C18:1) 21.30%, which was a plant oil-like fatty acid composition. This suggests that it has a high potential to be used as a biodiesel feedstock.