Effect of carbon source on lipid accumulation and biodiesel production of Yarrowia lipolytica

Yarrowia lipolytica (Y. lipolytica) is an oleaginous yeast that can utilize hydrophobic substrates as carbon source to produce single-cell lipids for biodiesel production. This study attempts to increase the lipid accumulation ability of Y. lipolytica by first gradually elevating pure oil substrate concentration during the cultivation and then adding short-chain carbon compounds, such as glucose and sodium acetate, to a culture substance according to the optimal oil concentration. Results showed that Y. lipolytica cultured under 40.0 g L^-1 oil concentration showed higher lipids (2.97 g L^-1) and lipid content (37.35%, DW) compared with that cultured under 20.0 g L^-1, where the corresponding values were 1.91 g L^-1 and 24.46%. By contrast, the lipid content of Y. lipolytica increased from 37.35 to 41.50% when the substrate was changed from 40.0 g L^-1 pure oil to 5% sodium acetate combined with 95% oil under the same total carbon concentration. However, lipid accumulation did not increase even though 15% sodium acetate or 5% glucose, or 15% glucose was added to the combined substrate. Moreover, the lipid biomodification of Y. lipolytica was evident when it was cultured under the oil concentration of 20.0 g L^-1. Therefore, the lipid accumulation of Y. lipolytica can be elevated through the gradient increase of oil concentration and by adding a suitable amount of easily degradable carbon source. Furthermore, the lipid biomodification of Y. lipolytica improves biodiesel quality.