Hyperproduction of poly(4-hydroxybutyrate) from glucose by recombinant Escherichia coli

Microbial Cell Factories

Research

De-Chuang Meng¹  Jin-Chun Chen¹  Xiao-Yun Zhou¹  Xiao-Xi Yuan¹  Wen-Jun Jiang¹  Guo-Qiang Chen²  Zhen-Yu Shi³  Lin-Ping Wu⁴ 

[1] Department of Biological Science and Biotechnology, MOE Key Lab of Bioinformatics and Systems Biology, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, 100084, Beijing, China;Department of Biological Science and Biotechnology, MOE Key Lab of Bioinformatics and Systems Biology, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, 100084, Beijing, China;Center for Nano and Micro Mechanics, Tsinghua University, 100084, Beijing, China;Department of Chemistry, University of Melbourne, 3052, Parkville, VIC, Australia;Department of Pharmaceutics and Analytical Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Copenhagen, Denmark;

关键词: Poly(4HB);    PHB;    Polyhydroxyalkanoates;    PhaP;    4-hydroxybutyrate;    Escherichia coli;    Metabolic engineering;    Synthetic biology;   

DOI  :  10.1186/1475-2859-11-54

 received in 2012-03-31, accepted in 2012-04-26,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundPoly(4-hydroxybutyrate) [poly(4HB)] is a strong thermoplastic biomaterial with remarkable mechanical properties, biocompatibility and biodegradability. However, it is generally synthesized when 4-hydroxybutyrate (4HB) structurally related substrates such as γ-butyrolactone, 4-hydroxybutyrate or 1,4-butanediol (1,4-BD) are provided as precursor which are much more expensive than glucose. At present, high production cost is a big obstacle for large scale production of poly(4HB).ResultsRecombinant Escherichia coli strain was constructed to achieve hyperproduction of poly(4-hydroxybutyrate) [poly(4HB)] using glucose as a sole carbon source. An engineering pathway was established in E. coli containing genes encoding succinate degradation of Clostridium kluyveri and PHB synthase of Ralstonia eutropha. Native succinate semialdehyde dehydrogenase genes sad and gabD in E. coli were both inactivated to enhance the carbon flux to poly(4HB) biosynthesis. Four PHA binding proteins (PhaP or phasins) including PhaP1, PhaP2, PhaP3 and PhaP4 from R. eutropha were heterologously expressed in the recombinant E. coli, respectively, leading to different levels of improvement in poly(4HB) production. Among them PhaP1 exhibited the highest capability for enhanced polymer synthesis. The recombinant E. coli produced 5.5 g L-1 cell dry weight containing 35.4% poly(4HB) using glucose as a sole carbon source in a 48 h shake flask growth. In a 6-L fermentor study, 11.5 g L-1 cell dry weight containing 68.2% poly(4HB) was obtained after 52 h of cultivation. This was the highest poly(4HB) yield using glucose as a sole carbon source reported so far. Poly(4HB) was structurally confirmed by gas chromatographic (GC) as well as 1H and 13C NMR studies.ConclusionsSignificant level of poly(4HB) biosynthesis from glucose can be achieved in sad and gabD genes deficient strain of E. coli JM109 harboring an engineering pathway encoding succinate degradation genes and PHB synthase gene, together with expression of four PHA binding proteins PhaP or phasins, respectively. Over 68% poly(4HB) was produced in a fed-batch fermentation process, demonstrating the feasibility for enhanced poly(4HB) production using the recombinant strain for future cost effective commercial development.

【 授权许可】

Unknown   
© Zhou et al; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.