二十碳五烯酸（EPA）是一种具有重要生理功能的n3-多不饱和脂肪酸，在保健食品、药品、饲料等行业具有广阔的商业前景，传统的鱼油来源难以满足EPA日益增长的市场需求。文中以裂殖壶菌为出发菌株，通过单因素实验在摇瓶水平优化了发酵温度，在5L发酵罐中进一步研究变温时间和溶氧对裂殖壶菌产EPA发酵性能的影响，建立了两阶段控温和低溶氧发酵策略，并研究了发酵过程中脂肪酸各组分的变化情况。结果表明，裂殖壶菌在阶段控温（28℃（0~24h）→34℃（24~120h））培养时，EPA含量最高，达到8.35%；在5L发酵罐中确定了最佳变温时间为24h，不同溶氧研究表明，中高溶氧（10%DO和25%DO）有利于裂殖壶菌的生长和油脂积累，但低溶氧（2%DO）更利于EPA的积累，EPA含量分别是中、高溶氧水平的2.05倍和4.98倍；建立了一种两阶段控温和低溶氧发酵策略，发酵至96 h时生物量、油脂产量、EPA含量和EPA产量分别达到56.60g/L、9.62g/L、12.50%和1.14g/L，与优化前相比，EPA的含量和产量分别提高了14.5倍和6.1倍。

Eicosapentaenoic acid （EPA） is a kind of n3-polyunsaturated fatty acid with important physiological functions.It has broad commercial prospects in health food，medicine，feed and other industries.However，the deep-sea fish oil as the traditional source of EPA cannot meet the increasing market demand.In this paper，Schizochytrium was taken as the original strain，and a two-stage temperature and low-dissolved-oxygen（TST-LDO） strategy is proposed.The effect of fermentation temperature was optimized by single factor experiment at the shaking flask level，and the effects of two-stage temperature change time and dissolved oxygen on the fermentation performance of EPA production in Schizochytrium were studied in a 5L fermenter.The change of fatty acid components in the process of fermentation was studied.The results show that the highest EPA content （8.35%） is obtained at two-stage-temperature strategy （28℃（0~24h）→34℃（24~120h））.The optimal temperature change time is 24h，which is determined in a 5 L fermenter.The results of different dissolved oxygen studies show that the medium and high dissolved oxygen （10%DO and 25%DO） are more conducive to the growth and lipid accumulation of Schizochytrium，but the low dissolved oxygen （2%DO） is more conducive to the accumulation of EPA，and the content of EPA is 2.05 times and 4.98 times of the medium and high dissolved oxygen level，respectively.When fermentation reached 96 h under TST-LDO strategy，the biomass，lipid yield，EPA content in total fatty acid and EPA yield reached 56.60g/L，9.62g/L，12.50% and 1.14g/L，respectively.Compared with the pretreatment，EPA content and EPA yield increased by 14.5 times and 6.1 times，respectively.