Gao Cuijuan, Zheng Yaqin
School of Life Sciences, Linyi University, Linyi 276000, Shandong, China.
Sheng Wu Gong Cheng Xue Bao. 2018 Mar 25;34(3):389-395. doi: 10.13345/j.cjb.170299.
Succinic acid is a high value-added organic acid widely used in food, chemical and pesticide industries. As a new robust non-conventional yeast, Yarrowia lipolytica attracts more and more attention due to its potential for industrial applications. Previously, we obtained a succinic acid-producing strain through gene deletion of succinic acid dehydrogenase subunit encoding gene Ylsdh5, resulting in the strain of PGC01003. However, the recombinant strain produced large amount of acetic acid due to imbalance between glycolysis and TCA cycle which hindered the efficient production of succinic acid. PDH bypass was interfered to decrease the overflow of acetic acid and produce succinic acid under natural pH. Acetic acid was reduced to 4.6 g/L through heterologous expression of acetyl coenzyme A synthase from Salmonella enteric, which was 75.4% of the control strain. Deletion of CoA-transferase gene Ylach1 eliminated acetate formation and improved succinic acid production, and the resulting strain produced as high as 7.0 g/L succinic acid. Our study provides foundation for further construction of efficient cell factory of succinic acid production.
琥珀酸是一种高附加值有机酸，广泛应用于食品、化工和农药行业。解脂耶氏酵母作为一种新型的强壮非常规酵母，因其在工业应用方面的潜力而受到越来越多的关注。此前，我们通过基因敲除琥珀酸脱氢酶亚基编码基因Ylsdh5获得了一株产琥珀酸菌株，即PGC01003菌株。然而，由于糖酵解和三羧酸循环之间的不平衡，该重组菌株产生了大量乙酸，这阻碍了琥珀酸的高效生产。通过干扰丙酮酸脱氢酶旁路来减少乙酸的溢流，并在自然pH条件下生产琥珀酸。通过异源表达来自肠炎沙门氏菌的乙酰辅酶A合成酶，乙酸含量降至4.6 g/L，为对照菌株的75.4%。敲除辅酶A转移酶基因Ylach1消除了乙酸的形成并提高了琥珀酸产量，所得菌株琥珀酸产量高达7.0 g/L。我们的研究为进一步构建高效的琥珀酸生产细胞工厂奠定了基础。
