Lipid production by yeasts grown on crude glycerol from biodiesel industry.

The main carbon source used for growth by four yeast strains (Yarrowia lipolytica CCMA 0357, Y. lipolytica CCMA 0242, Wickerhamomyces anomalus CCMA 0358, and Cryptococcus humicola CCMA 0346) and their lipid production were evaluated, using different concentrations of crude and pure glycerol and glucose. Whereas crude glycerol (100 g/L) was the main carbon source used by Y. lipolytica CCMA 0357 (nearly 15 g/L consumed at 120 hr) and W. anomalus CCMA 0358 (nearly 45.10 g/L consumed at 48 hr), pure glycerol (150 g/L) was the main one used by C. humicola CCMA 0346 (nearly 130 g/L consumed). On the other hand, Y. lipolytica CCMA 0242 used glucose (100 g/L) as its main source of carbon (nearly 96.48 g/L consumed). Y. lipolytica CCMA 0357 demonstrated the highest lipid production [about 70% (wt/wt)], forming palmitic (45.73% of fatty acid composition), stearic (16.43%), palmitoleic (13.29%), linolenic (10.77%), heptadecanoic (4.07%), and linoleic (14.14%) acids. Linoleic acid, an essential fatty acid, was produced by all four yeast strains but in varying degrees, representing 70.42% of the fatty acid profile of lipids produced by C. humicola CCMA 0346.