Construction of Efficient Platform Escherichia coli Strains for Polyhydroxyalkanoate Production by Engineering Branched Pathway.

Hye-Rim Jung,Yu-Mi Moon,Hun-Suk Song,Ranjit Gurav,Shashi Bhatia,Su-Yeon Yang,Yung-Hun Yang,Eun-Jung Kim,Tae-Rim Choi,Byung-Gee Kim

doi:10.3390/polym11030509

Hye-Rim Jung, Yu-Mi Moon + Show 8 more

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https://doi.org/10.3390/polym11030509

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Journal: Polymers	Publication Date: Mar 18, 2019
Citations: 58	License type: CC BY 4.0

Affiliation: Konkuk University, Seoul National University

Abstract

Polyhydroxyalkanoate (PHA) is a potential substitute for petroleum-based plastics and can be produced by many microorganisms, including recombinant Escherichia coli. For efficient conversion of substrates and maximum PHA production, we performed multiple engineering of branched pathways in E. coli. We deleted four genes (pflb, ldhA, adhE, and fnr), which contributed to the formation of byproducts, using the CRISPR/Cas9 system and overexpressed pntAB, which catalyzes the interconversion of NADH and NADPH. The constructed strain, HR002, showed accumulation of acetyl-CoA and decreased levels of byproducts, resulting in dramatic increases in cell growth and PHA content. Thus, we demonstrated the effects of multiple engineering for redirecting carbon flux into PHA production without any concerns regarding simultaneous deletion.

Highlights

Polyhydroxyalkanoate (PHA), a bio-based, biodegradable polymer, is a promising substitute for petroleum-derived plastics [1,2]
PHA has been shown to be produced by many microorganisms, including R. eutropha, A. latus, and recombinant E. coli using diverse inexpensive carbon sources [4,7,8]
We reported the effects of multiple engineering for balancing metabolic pathways to avoid byproduct formation

Summary

Introduction

Polyhydroxyalkanoate (PHA), a bio-based, biodegradable polymer, is a promising substitute for petroleum-derived plastics [1,2]. This polymer is biocompatible and, has several medical applications [3]. Poly(3-hydroxybutyrate) (PHB), the most extensively studied member of the PHA family, is readily produced in several bacteria, including Ralstonia eutropha, Alcaligenes latus, Azotobacter vinelandii, and Pseudomonas, as part of their natural metabolism [4,5,6]. After the condensation of two acetyl-CoA molecules to one acetoacetyl-CoA by β-ketothiolase (BktB), which is subsequently reduced to 3-hydroxybutyryl-CoA by NADPH-dependent acetoacetyl-CoA reductase (PhaB), the latter molecule is polymerized as a monomer to PHB by PHA polymerase (PhaC) [4,9]

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Conclusion