Study on the Supply Strategy of EPA Dissolved Oxygen in Mortierella alpina

• 1、Food science School, Jiangnan University, Jiangsu Wuxi, 214100

Abstract：EPA (cis-5, 8, 11, l4, 17-eicosapentaenoic acid) is a kind of omega-3 series long-chain polyunsaturated fatty acid, which has special physiological functions such as anti-coagulation, anti-cancer, anti-inflammatory, anti-cardiovascular disease and lipid-lowering. Due to limited sources of fish oil and large market demand, microbial oil has become a research hotspot. The Oleaginous microorganism mortierella alpina is an industrial strain producing arachidonic acid (AA; C20:4; ω-6) and is also a potential strain for EPA industrialization. In the early stage of the laboratory, a recombinant strain of Mortierella alpina CCFM698 which can accumulate EPA at room temperature was obtained by overexpressing the omega-3 desaturase PPD17 derived from Phytophthora parasitica. Insufficient dissolved oxygen may be a key factor limiting the further efficient synthesis of EPA from Mortierella alpina. In order to meet the demand of EPA for dissolved oxygen in recombinant strains, this study investigated the effects of different speeds of agitator, oxygen-enriched media addition and added oxygen-enriched air to enhance oxygen partial pressure on the production of EPA. The results showed that the appropriate speed of agitator was 400rpm. The addition of 4% n-hexane, an oxygen-rich medium, had a certain effect on the dissolved oxygen of the fermentation system, but had no obvious effect on the increase of EPA yield. The oxygen-enriched air is maintained at a relative dissolved oxygen level of not less than 10%, and the EPA production is increased from 0.56 g/L to 1.01 g/L, which is 1.82 times the initial condition.

Keywords： Food science Mortierella alpina EPA DO fermentation optimization