透明颤菌血红蛋白基因表达对腐霉合成二十碳五烯酸的作用

Effect of expression of Vitreoscilla hemoglobin gene on eicosapentaenoic acid synthesis in Pythium

通过研究腐霉菌体内透明颤菌血红蛋白基因的表达及工程菌株的生长代谢特性,解决其发酵过程中溶解氧限制的问题,从而提高二十碳五烯酸的产量。构建了血红蛋白基因表达载体,通过农杆菌LBA4404介导的方法导入丝状真菌腐霉,成功构建血红蛋白基因腐霉工程菌,摇瓶发酵研究血红蛋白基因表达对腐霉工程菌生长代谢特性的影响。研究结果表明血红蛋白基因正常表达,在优化的培养条件下,摇瓶结果显示,腐霉V1的生物量、油脂量及油脂中二十碳五烯酸含量较出发菌株分别提高了4.80%,4.82%和11.69%,EPA产量为1 004.96 mg/L。

The Vitreoscilla hemoglobin gene was expressed in Pythium to alleviate oxygen limitation and improve the yields of eicosapentaenoic acid during fermentation. Furthermore, the growth characteristic of recombinant strain was studied. We constructed an expression vector containing hemoglobin gene and transformed it into Pythium through the mediation of Agrobacterium LBA4404. We evaluated the effect of hemoglobin gene on growth of Pythium and biosynthesis of eicosapentaenoic acid in shake flasks. The results showed that the Pythium V1 containing hemoglobin gene was obtained and the hemoglobin gene was successfully expressed. Through the optimization of culture conditions, the biomass, lipid in mycelium and content of eicosapentaenoic acid in lipid of Pythium V1 respectively in- creased 4.8% , d. 82% and 11.69% compared with the parental strain in shake flasks, and the yields of EPA was 1 004.96 mg/L. The expression of hemoglobin gene in Pythium could improve the yields of eicosapentaenoic acid, thus it showed a good application prospect to solve the problem about the low dissolved oxygen in high density fermentation of the filamentous fungi.