Dissolved oxygen and pH are critical factors influencing cell growth and metabolism. In our previous work, we constructed the recombinant strain Mortierella alpina CCFM698, which has the ability to produce EPA at room temperature. However, our experiments showed that the dissolved oxygen produced by the aeration and agitation of the fermenter was insufficient for cell growth and EPA synthesis by this recombinant strain. Moreover, the optimum pH for cell growth was incompatible with that of EPA accumulation. This study introduced a combined strategy of two-stage pH control with oxygen-enriched air in fed-batch fermentation to facilitate both cell growth and EPA production in M. alpina CCFM698. After 10 days of fermentation in a 7.5 L tank, the biomass production reached 41.2 g/L, with a lipid content of 31.5%, and EPA accounting for 26.7% of total lipids. The final EPA production reached 3.47 g/L, which is the highest yet achieved by M. alpina. This study reveals the critical role of dissolved oxygen and pH control for EPA production of M. alpina, and provides an easy and efficient strategy for industrial production of EPA.

中文翻译：

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两阶段pH控制与富氧空气策略相结合，可通过分批分批发酵的高山被孢霉CCFM698高效生产EPA。

溶解氧和pH是影响细胞生长和代谢的关键因素。在我们之前的工作中，我们构建了重组菌株高山被孢霉CCFM698，该菌株具有在室温下产生EPA的能力。然而，我们的实验表明，通过发酵罐的曝气和搅拌产生的溶解氧不足以通过该重组菌株进行细胞生长和EPA合成。此外，细胞生长的最佳pH与EPA积累的pH不相容。这项研究引入了分批补料发酵中两阶段控制pH值和富氧空气的组合策略，以促进高山被孢霉CCFM698的细胞生长和EPA产生。在7.5 L的罐中发酵10天后，生物质产量达到41.2 g / L，脂质含量为31.5％，EPA占26。总脂质的7％。EPA的最终产量达到了3.47 g / L，这是Alpina的最高产量。这项研究揭示了溶解氧和pH值控制在EPA产生的M. alpina中的关键作用，并为工业生产EPA提供了简单有效的策略。