大肠杆菌
甘油
化学
发酵
生物化学
产量(工程)
定向进化
甘油激酶
链霉菌
组合化学
生物
细菌
基因
材料科学
突变体
冶金
遗传学
作者
Chao Zhang,Chao Qian,Fan Feng,Ji‐Xin Tang,Tao Zhan,Honglei Wang,Xueli Zhang
出处
期刊:Journal of Industrial Microbiology & Biotechnology
[Oxford University Press]
日期:2021-07-01
卷期号:48 (7-8)
被引量:8
摘要
D-glycerate is an attractive chemical for a wide variety of pharmaceutical, cosmetic, biodegradable polymers, and other applications. Now several studies have been reported about the synthesis of glycerate by different biotechnological and chemical routes from glycerol or other feedstock. Here, we present the construction of an Escherichia coli engineered strain to produce optically pure D-glycerate by oxidizing glycerol with an evolved variant of alditol oxidase (AldO) from Streptomyces coelicolor. This is achieved by starting from a previously reported variant mAldO and employing three rounds of directed evolution, as well as the combination of growth-coupled high throughput selection with colorimetric screening. The variant eAldO3-24 displays a higher substrate affinity toward glycerol with 5.23-fold than the wild-type AldO, and a 1.85-fold increase of catalytic efficiency (kcat/KM). Then we introduced an isopropyl-β-D-thiogalactopyranoside (IPTG)-inducible T7 expression system in E. coli to overexpress the variant eAldO3-24, and deleted glucosylglycerate phosphorylase encoding gene ycjM to block the consumption of D-glycerate. Finally, the resulting strain TZ-170 produced 30.1 g/l D-glycerate at 70 h with a yield of 0.376 mol/mol in 5-l fed-batch fermentation.
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