改造底物转运和副产物途径强化1,3-丙二醇合成
Modification of substrate transport and by-product pathways to enhance the synthesis of 1,3-propanediol
底物转运是细胞生长和代谢的首要步骤，而副产物积累则会竞争碳流和还原力，影响产物合成。为提高甘油摄入效率，本文分别表达了来自克雷伯氏菌(Klebsiellae pneumoniae)和大肠杆菌(Escherichia coli)的甘油转运蛋白GlpF。其中，K. pneumonia ZG25表达内源kGlpF，甘油脱水酶(GDHt)活性提高了123.6%，1,3-丙二醇(1,3-propanediol，1,3-PDO)产量由17.2 g/L提高到19.2 g/L。为减少乳酸积累，敲除乳酸脱氢酶基因ldhA，生物量提高了5.3%，1,3-PDO产量达到22.1 g/L，甘油转化率从0.58 mol/mol提高到0.66 mol/mol。但进一步敲除α-乙酰乳酸基因budB后，菌体生长和1,3-PDO合成则被显著抑制。上述结果表明，通过改造底物转运和副产物途径，强化了底物转运效率、弱化了副产物积累，有效提高了1,3-PDO产量。
Substrate transport is the first step of cell growth and metabolism, while by-products accumulation affects product synthesis by competing for carbon flow and reducing power. To increase glycerol uptake efficiency, the glycerol transporter GlpF from Klebsiellae pneumoniae and Escherichia coli were overexpressed respectively. Expressing endogenous kGlpF in K. pneumoniae, glycerol dehydratase (GDHt) activity increased by 123.6%, and 1,3-propanediol (1,3-PDO) titer increased from 17.2 g/L to 19.2. g/L. The ldhA gene encoding the lactate dehydrogenase was deleted to reduce lactate accumulation. The mutant strain produced 22.1 g/L 1,3-PDO with a 5.3% increase of biomass, and improved glycerol conversion rate from 0.58 to 0.66 mol/mol. However, further deletion of the budB gene encoding the α-acetolactate, cell growth and 1,3-PDO synthesis were significantly inhibited. These results indicate that 1,3-PDO production is effectively improved by improvement of substrate transport efficiency and weakening of by-product pathways.
宗红、滕宇、方慧英、诸葛斌、陆信曜、谢梦梦
生物工程学生物化学
甘油转运副产物13-丙二醇Klebsiellae pneumoniae
Glycerol transportBy-product13-propanediolKlebsiellae pneumoniae
宗红,滕宇,方慧英,诸葛斌,陆信曜,谢梦梦.改造底物转运和副产物途径强化1,3-丙二醇合成[EB/OL].(2018-09-11)[2025-08-03].http://www.paper.edu.cn/releasepaper/content/201809-19.点此复制
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