Lipase Secretion and Citric Acid Production in Yarrowia lipolytica Yeast Grown on Animal and Vegetable Fat

The aim of the study was to investigate the potentiality of the utilization of raw agroindustrial fat for the biotechnological production of valuable products (lipase and citric acid) by the yeast Yarrowia (Candida) lipolytica. Thirty strains of the aforementioned species were investigated for their capability of lipase secretion and citric acid production on media containing animal fat or rapeseed oil as a sole carbon and energy source. Strain Y. lipolytica 704, exhibiting the highest lipase activity on rapeseed oil (2760 U/mL), was selected for the study of biochemical peculiarities of cell growth, and strain Y. lipolytica 187/1, exhibiting the maximum citric acid synthesis, was selected for the subsequent studies on citric acid production. A relationship between lipase production and residual rapeseed oil concentration was studied. The essential factor for lipase production was found to be the concentration of rapeseed oil in the medium, which should be no less than 5 g/L. Under optimal conditions of cultivation, citric acid production by rapeseed-oil-grown yeast Yarrowia lipolytica 187/1 amounted to 135 g/L; specific rate of citric acid production reached m(CA)/m(cell)=127 mg/(g times h); mass yield (Y sub(CA)) and energy yield (eta sub(CA)) were 1.55 and 0.41, respectively.