Engineering of a Synthetic Metabolic Pathway for the Assimilation of (d)-Xylose into Value-Added Chemicals

详细信息    查看全文

• 作者：Yvan Cam ; Ceren Alkim ; Debora Trichez ; Vincent Trebosc ; Amélie Vax ; François Bartolo ; Philippe Besse ; Jean Marie François ; Thomas Walther
• 刊名：ACS Synthetic Biology
• 出版年：2016
• 出版时间：July 15, 2016
• 年：2016
• 卷：5
• 期：7
• 页码：607-618
• 全文大小：526K
• 年卷期：0
• ISSN：2161-5063

文摘

A synthetic pathway for (d)-xylose assimilation was stoichiometrically evaluated and implemented in Escherichia coli strains. The pathway proceeds via isomerization of (d)-xylose to (d)-xylulose, phosphorylation of (d)-xylulose to obtain (d)-xylulose-1-phosphate (X1P), and aldolytic cleavage of the latter to yield glycolaldehyde and DHAP. Stoichiometric analyses showed that this pathway provides access to ethylene glycol with a theoretical molar yield of 1. Alternatively, both glycolaldehyde and DHAP can be converted to glycolic acid with a theoretical yield that is 20% higher than for the exclusive production of this acid via the glyoxylate shunt. Simultaneous expression of xylulose-1 kinase and X1P aldolase activities, provided by human ketohexokinase-C and human aldolase-B, respectively, restored growth of a (d)-xylulose-5-kinase mutant on xylose. This strain produced ethylene glycol as the major metabolic endproduct. Metabolic engineering provided strains that assimilated the entire C2 fraction into the central metabolism or that produced 4.3 g/L glycolic acid at a molar yield of 0.9 in shake flasks.