The Preliminary Study Of Fermentation Conditions For Polyunsaturated Fatty Acids Production By Mortierella Aplina

Research has shown that polyunsaturated fatty acids (PUFA) has various physiological functions. The tranditional sources of PUFA have relatively low PUFA contents and the oil extraction process is fairly costly, so the yields were unable to meet the increasing market demand. Filamentous fungi Mortierella aplina is a potential producer of PUFA, in which the content of lipid exceeds 40% of dry cell weight, especially arachidonic acid is the most abundant, accounting for PUFA content of 68.5%-78.8%. In some countries, such as Japan, M. aplina has been used to produce arachidonic acid extensively, but undeveloped in our country. In order to speed up the pace of industrial production of PUFA in our country, the study of the fermentation conditions of M. aplina is really valueble for us. At the same time, it has a positive role in promoting the development of the entire single cell oil industry. So our intention is to low the costs by use inexpensive culture media, to increase the yields of n-3 polyunsaturated fatty acids which is more valuble.According to the principles on lipid accumulation of oleaginicity, first of all, carbon source and nitrogen source were studied,which were the two key factors in M. aplina fermentation. The results showed the best nitrogen source was defatted soybean powder 18g/L and nitric acid potassium 8g/L. Glucose was the best carbon source, but the high concentration of initial glucose was negative for the growth of M. aplina. Glycerol is a alternative carbon source for industrial production of PUFA. The tempreture transformation strategy, incubating M. aplina at 20℃for 48 hours first, and then transfer to 12℃for another 144 hours, is good for the production of n-3 PUFA. The yield of n-3 PUFA improved by 1.9 times. It decreased the cost greatly, and improved the development of the single cell oil industry.