Poly(4-hydroxybutyrate) (P4HB) production in recombinant Escherichia coli: P4HB synthesis is uncoupled with cell growth

Microbial Cell Factories

Research

Qun Ren¹  Linda Thöny-Meyer¹  Manfred Zinn²  Sylvaine Le Meur³  Thomas Egli⁴ 

[1] Laboratory for Biomaterials, Swiss Federal Laboratories for Materials Science and Technology (Empa), Lerchenfeldstrasse 5, CH-9014, St. Gallen, Switzerland;Laboratory for Biomaterials, Swiss Federal Laboratories for Materials Science and Technology (Empa), Lerchenfeldstrasse 5, CH-9014, St. Gallen, Switzerland;Biotechnology, HES-SO Valais Wallis, P.O.B. 2134, Rue du Rawyl 64, CH-1950, Sion, Switzerland;Laboratory for Biomaterials, Swiss Federal Laboratories for Materials Science and Technology (Empa), Lerchenfeldstrasse 5, CH-9014, St. Gallen, Switzerland;Swiss Federal Institute of Technology Zurich (ETH), Environmental Sciences, Rämistrasse 101, 8092, Zurich, Switzerland;Swiss Federal Institute of Technology Zurich (ETH), Environmental Sciences, Rämistrasse 101, 8092, Zurich, Switzerland;Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), P.O. Box 610, Überlandstrasse 133, CH-8600, Dübendorf, Switzerland;

关键词: P4HB;    Xylose;    Bioprocess development;    Batch culture;   

DOI  :  10.1186/1475-2859-12-123

 received in 2013-10-30, accepted in 2013-12-02,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundPoly(4-hydroxybutyrate) (P4HB), belonging to the family of bacterial polyhydroxyalkanoates (PHAs), is a strong, flexible and absorbable material which has a large variety of medical applications like tissue engineering and drug delivery. For efficient production of P4HB recombinant Escherichia coli has been employed. It was previously found that the P4HB synthesis is co-related with the cell growth. In this study, we aimed to investigate the physiology of P4HB synthesis, and to reduce the total production cost by using cheap and widely available xylose as the growth substrate and sodium 4-hydroxybutyrate (Na-4HB) as the precursor for P4HB synthesis.ResultsSix different E. coli strains which are able to utilize xylose as carbon source were compared for their ability to accumulate P4HB. E. coli JM109 was found to be the best strain regarding the specific growth rate and the P4HB content. The effect of growth conditions such as temperature and physiological stage of Na-4HB addition on P4HB synthesis was also studied in E. coli JM109 recombinant in batch culture. Under the tested conditions, a cellular P4HB content in the range of 58 to 70% (w w-1) and P4HB concentrations in the range of 2.76 to 4.33 g L-1 were obtained with a conversion yield (YP4HB/Na-4HB) of 92% w w-1 in single stage batch cultures. Interestingly, three phases were identified during P4HB production: the “growth phase”, in which the cells grew exponentially, the “accumulation phase”, in which the exponential cell growth stopped while P4HB was accumulated exponentially, and the “stagnation phase”, in which the P4HB accumulation stopped and the total biomass remained constant.ConclusionsP4HB synthesis was found to be separated from the cell growth, i.e. P4HB synthesis mainly took place after the end of the exponential cell growth. High conversion rate and P4HB contents from xylose and precursor were achieved here by simple batch culture, which was only possible previously through fed-batch high cell density cultures with glucose.

【 授权许可】

Unknown   
© Le Meur et al.; licensee BioMed Central Ltd. 2013. 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. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.