Producing Functional Fatty Acid DHA from Corn Steep Liquor by Aurantiochytrium SW1

Thraustochytrium has a relatively high lipid content in the cell and its lipid content can account up to 70% of the dry cell weight. It is an important raw material for the third-generation biodiesel production and the production of functional fatty acid Docosahexaenoic Acid (DHA). However, the high cost of traditional fermentation medium has hindered the industrial production of lipid. Therefore, searching for raw materials that can be used by thraustochytrid with a wide range of sources and low prices has become a research hotspot in the production of lipids by thraustochytrid. In this study, corn steep liquor was applied for lipid production in thraustochytrid Aurantiochytrium SW1, various factors of corn medium were optimized by using Response Surface Methodology (RSM), including glucose concentration, Rotation Speed, Kinetin concentration and dilution rate of corn steep liquor. The optimal conditions were finally obtained as 72.37 g/L glucose, 2.28 mg/L kinetin, 270 rpm of rotation speed and 15 times of corn pulp dilution. The biomass, lipid and DHA yields obtained under the optimized conditions were 13.5, 7.9 and 42% of total fatty acids, respectively. Comparison with the traditional medium, the biomass, lipid and DHA production were promoted by 14.8, 31.6 and 31.3% respectively. The optimized medium using cheap corn steep liquor showed a better production level, which proved the feasibility of culturing Aurantiochytrium SW1 with cheap raw materials.