Improving the lipid accumulation properties of the yeast cells for biodiesel production using molasses.

In this article the high lipid accumulation potential of Candida lipolytica, Candida tropicalis and Rhodotorula mucilaginosa cells were shown in molasses medium. Four different pH values were examined (4-7) to discover the optimum lipid accumulation medium. Varied concentrations of (NH₄)₂SO₄ (0.5, 1.0, 1.5 g/L) and molasses (6%, 8%, 10%) were tested to find the optimum carbon and nitrogen amounts for the highest cellular lipid production. It is shown that the maximum lipid content could be achieved in the medium containing 8% molasses solution and 1.0 g/L (NH₄)₂SO₄ at pH 5 after four days of incubation time. The maximum lipid contents and methyl ester yields were measured as 59.9% and 84.9% for C. lipolytica, 46.8% and 93.2% for C. tropicalis, 69.5% and 92.3% for R. mucilaginosa. Because of the dominant fatty acids were C16 and C18 in the lipids of yeast cells, these crude lipids could be promising feedstock for biodiesel production.