Microbial lipid presents a potential industrial and financial interest due to its specific characteristics. Especially various oleaginous microorganisms have been used to produce lipids rich in polyunsaturated fatty acids (PUFAs) which are of medical and dietetic interest. One of the examples is microbial production of arachidonic acid (ARA), which has broad applications in medicine, pharmacology, cosmetics, food industry, agriculture, and other fields. The traditional sources of ARA-rich lipid are egg yolks and some kinds of animal tissues. However, isolation lipid from these organs is typically costly and insufficient to meet the market demand for ARA production because these organs contain only small amounts of ARA. Microbial lipid, which has been suggested as a viable alternative to plant oils and fats, could be used as an alternative source of ARA-rich lipid. In this study, a three-stage fermentation strategy was designed for efficient ARA-rich lipid production by Mortierella alpina. In the first stage, cells were inoculated in a nutrient-rich medium for rapid propagation. In the second stage, mycelia were collected and then cultivated in glucose solution to achieve high cellular lipid contents. In the third stage, mycelia were cultivated in the glucose-absent medium to obtain rapid ARA accumulation. By using this fermentation strategy, high dry cell weight, lipid, and ARA concentration reached 41.6, 26.6, and 11.4 g/L, respectively. The results demonstrated that cell propagation, lipid biosynthesis, and ARA accumulation process can be significantly spatially separated, and allowing further optimization to improve the efficiency of each stage. This was the first report of using a three-stage fermentation strategy for ARA-rich lipid production, and it could be applied to the other similar oleaginous microorganisms to acquire high related PUFAs accumulation.

Efficient arachidonic acid-rich lipid production by Mortierella alpina

246th National Meeting (2013)

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