产青蒿二烯的人工酵母细胞的构建及发酵优化

为了异源合成抗疟疾药物青蒿素重要前体青蒿二烯, 以酿酒酵母作为底盘细胞, 利用基因工程手段构建功能人工酵母细胞。为提高基因拷贝数, 并增加重组菌株基因型的稳定性, 选择酵母基因组中多拷贝位点Delta为整合点, 实现酿酒酵母内源基因tHMGR和ERG20的过表达以及外源基因ADS的整合。过表达tHMGR和ERG20基因增加了酵母体内半萜类物质共同前体法尼基焦磷酸FPP的积累量;而导入外源基因ADS, 实现了酵母生产青蒿二烯。经过摇瓶发酵优化实验, 人工酵母菌株青蒿二烯产量为225.3 mg·L^-1;为了进一步提高青蒿二烯产量, 经过发酵过程优化和补料策略, 人工酵母菌株在5 L发酵罐中青蒿二烯产量达到1.05 g·L^-1。

Construction of artificial yeast cell for producing amorphadiene,and optimization of fermentation

Amorphadiene, the role precursor of anti-malaria drug artemisinin, was produced by artificial Saccharomyces cerevisiae cells that were constructed under guidance of gene engineering methods. Homologous genes tHMGR and ERG20 as well as heterogenous gene ADS were integrated into yeast genome at the multiple copies Delta sites. Two advantages of this strategy were to increase copy number of genes and to enhance the stability of recombinant strains genotype. Overexpression of tHMGR and ERG20 genes increased accumulation of FPP, the common precursor for sesquiterpenoids. The artificial yeast strains could produce amorphadiene by introducing heterogenous gene ADS. The production of amorphadiene was increased to 225.3 mg·L^-1 in 50 ml flask fermentation through optimizing fermentation condition. In 5 L fermentor, production of amorphadiene was increased to 1.05 g·L^-1 after optimization of fermentation process and the fed-batch feeding strategy.