Song Tianqing, Wu Nan, Wang Chen, Wang Ying, Chai Fenghua, Ding Mingzhu, Li Xia, Yao Mingdong, Xiao Wenhai, Yuan Yingjin
Frontier Science Center for Synthetic Biology, Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.
Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, China.
Front Bioeng Biotechnol. 2020 Sep 4;8:578005. doi: 10.3389/fbioe.2020.578005. eCollection 2020.
Crocetin, an important natural carotenoid dicarboxylic acid with high pharmaceutical values, has been successfully generated from glucose by engineered in our previous study. Here, a systematic optimization was executed for crocetin overproduction in yeast. The effects of precursor enhancement on crocetin production were investigated by blocking the genes involved in glyoxylate cycle [citric acid synthase () and malic acid synthase ()]. Crocetin titer was promoted by 50% by Δ compared to that of the starting strain. Then, the crocetin production was further increased by 44% through introducing the forward fusion enzymes of CrtZ (CrtZ from )-CCD2 (CCD2 from ). Consequently, the crocetin titer reached to 1.95 ± 0.23 mg/L by overexpression of CrtZ-CCD2 followed by medium optimization. Eventually, a titer of 12.43 ± 0.62 mg/L crocetin was achieved in 5-L bioreactor, which is the highest crocetin titer reported in micro-organisms.
藏红花酸是一种具有高药用价值的重要天然类胡萝卜素二羧酸，在我们之前的研究中已通过工程改造从葡萄糖成功合成。在此，对酵母中藏红花酸的过量生产进行了系统优化。通过阻断参与乙醛酸循环的基因[柠檬酸合酶（）和苹果酸合酶（）]，研究了前体增强对藏红花酸生产的影响。与起始菌株相比，Δ使藏红花酸产量提高了50%。然后，通过引入CrtZ（来自的CrtZ）-CCD2（来自的CCD2）的正向融合酶，藏红花酸产量进一步提高了44%。因此，通过过表达CrtZ-CCD2并随后进行培养基优化，藏红花酸产量达到1.95±0.23mg/L。最终，在5-L生物反应器中实现了12.43±0.62mg/L的藏红花酸产量，这是微生物中报道的最高藏红花酸产量。
