Engineering of Serine-Deamination pathway, Entner-Doudoroff pathway and pyruvate dehydrogenase complex to improve poly3-hydroxybutyrate production in Escherichia coliReport as inadecuate




Engineering of Serine-Deamination pathway, Entner-Doudoroff pathway and pyruvate dehydrogenase complex to improve poly3-hydroxybutyrate production in Escherichia coli - Download this document for free, or read online. Document in PDF available to download.

Microbial Cell Factories

, 13:172

Systems biotechnology and metabolic engineering

Abstract

BackgroundPoly3-hydroxybutyrate PHB, a biodegradable bio-plastic, is one of the most common homopolymer of polyhydroxyalkanoates PHAs. PHB is synthesized by a variety of microorganisms as intracellular carbon and energy storage compounds in response to environmental stresses. Bio-based production of PHB from renewable feedstock is a promising and sustainable alternative to the petroleum-based chemical synthesis of plastics. In this study, a novel strategy was applied to improve the PHB biosynthesis from different carbon sources.

ResultsIn this research, we have constructed E. coli strains to produce PHB by engineering the Serine-Deamination SD pathway, the Entner-Doudoroff ED pathway, and the pyruvate dehydrogenase PDH complex. Firstly, co-overexpression of sdaA encodes L-serine deaminase, L-serine biosynthesis genes and pgk encodes phosphoglycerate kinase activated the SD Pathway, and the resulting strain SD02 pBHR68, harboring the PHB biosynthesis genes from Ralstonia eutropha, produced 4.86 g-L PHB using glucose as the sole carbon source, representing a 2.34-fold increase compared to the reference strain. In addition, activating the ED pathway together with overexpressing the PDH complex further increased the PHB production to 5.54 g-L with content of 81.1% CDW. The intracellular acetyl-CoA concentration and the NADPH-NADP ratio were enhanced after the modification of SD pathway, ED pathway and the PDH complex. Meanwhile, these engineering strains also had a significant increase in PHB concentration and content when xylose or glycerol was used as carbon source.

ConclusionsSignificant levels of PHB biosynthesis from different kinds of carbon sources can be achieved by engineering the Serine-Deamination pathway, Entner-Doudoroff pathway and pyruvate dehydrogenase complex in E. coli JM109 harboring the PHB biosynthesis genes from Ralstonia eutropha. This work demonstrates a novel strategy for improving PHB production in E. coli. The strategy reported here should be useful for the bio-based production of PHB from renewable resources.

KeywordsEscherichia coli poly3-hydroxybutyrate L-serine deaminate Entner-Doudoroff pathway Pyruvate dehydrogenase complex Yan Zhang and Zhenquan Lin contributed equally to this work.

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Author: Yan Zhang - Zhenquan Lin - Qiaojie Liu - Yifan Li - Zhiwen Wang - Hongwu Ma - Tao Chen - Xueming Zhao

Source: https://link.springer.com/







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