Physiologo-biochemical characteristics of citrate-producing yeast Yarrowia lipolytica grown on glycerol-containing waste of biodiesel industry

In this study, physiologo-biochemical characteristics of citrate-producing yeast Yarrowia lipolytica grown on glycerol-containing waste of biodiesel industry were studied by an investigation of growth dynamics, the consumption of glycerol, and the fatty acid fractions from waste as well as by measuring the activities of enzymes involved in the metabolism of waste. It was shown that Y. lipolytica realizes concurrent uptake of glycerol and the fatty acid fractions during conversion of glycerol-containing waste, although glycerol was utilized at a higher rate than fatty acids. Under optimal feeding of glycerol-containing waste by portions of 20 g l⁻¹, the citric acid production and the ratio between citric acid and isocitric acid depended on the strain used. It was revealed that wild strain Y. lipolytica VKM Y-2373 produced citrate and isocitrate with a ratio of 1.7:1, while the mutant strain Y. lipolytica NG40/UV7 synthesized presumably citric acid (122.2 g l⁻¹) with a citrate-to-isocitrate ratio of 53:1 and the yield of 0.95 g g⁻¹.