大肠杆菌利用葡萄糖和木糖合成乙醇酸、乳酸和3-羟基丁酸共聚酯

Microbial production of poly (glycolate-co-lactate-co-3- hydroxybutyrate) from glucose and xylose by Escherichia coli

摘要:

以大肠杆菌为宿主，构建了以葡萄糖和木糖为底物获得乙醇酸、乳酸和3-羟基丁酸共聚酯的生物合成途径，包括过表达塔格糖-3-差向异构酶、核酮糖激酶、醛缩酶、醛脱氢酶、丙酰辅酶A转移酶、β-酮硫解酶、乙酰乙酰辅酶A还原酶和聚合酶等。在此基础上，表达聚羟基脂肪酸酯颗粒结合蛋白，提高了聚合物的合成，重组菌的细胞干重达到3.73 g/L，含有38.72 wt%的共聚酯。采用混菌共培养策略，实现以葡萄糖和木糖混合物为底物合成共聚酯，摇瓶实验中细胞干重达到4.01 g/L，含有21.54 wt%的聚合物。文中提供了一种以葡萄糖和木糖混合物为碳源合成聚合物的方法，为下一步纤维素水解物的有效利用提供了参考。

关键词:聚羟基脂肪酸酯，乙醇酸，乳酸，3-羟基丁酸，葡萄糖，木糖

Abstract:

Escherichia coli was metabolically engineered to produce poly(glycolate-co-lactate-co-3-hydroxybutyrate) using glucose and xylose as carbon sources. The combinatorial biosynthetic route was constructed by the overexpression of a series of enzymes including D-tagatose 3-epimerase, L-fuculokinase, L-fuculose-phosphate aldolase, aldehyde dehydrogenase, propionyl-CoA transferase, β-ketothiolase, acetoacetyl-CoA reductase, and polyhydroxyalkanoate synthase. Overexpression of polyhydroxyalkanoate granule associated protein significantly improved biopolymer synthesis, and the recombinant strain reached 3.73 g/L cell dry weight with 38.72% (W/W) biopolymer content. A co-culture engineering strategy was developed to produce biopolymer from a mixture of glucose and xylose, achieving 4.01 g/L cell dry weight containing 21.54% (W/W) biopolymer. The results of this work offer an approach for simultaneously utilizing glucose and xylose and indicate the potential for future biopolymer production from lignocellulosic biomass.

Key words:polyhydroxyalkanoate, glycolate, lactate, 3-hydroxybutyrate, glucose, xylose