Biotechnology Bulletin ›› 2020, Vol. 36 ›› Issue (7): 112-118.doi: 10.13560/j.cnki.biotech.bull.1985.2020-0004

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Multiple-site Mutations in Escherichia coli Capable of High-density Growing Induced from the Biosynthesis of Polyhydroxybutyrate

CHEN Qiao1,2, WU Hai-ying1,3, WANG Zong-shou4, XIE Yu-kang1,2, LI Yi-qing1,3, SUN Jun-song1,2,3   

  1. 1. Shanghai Advanced Research Institute,Chinese Academy of Sciences,Shanghai 201210;
    2. University of Chinese Academy of Sciences,Beijing 100049;
    3. Shanghai Tech University,Shanghai 201210;
    4. Animal Husbandry Station of Nanping City,Nanping 353000
  • Received:2020-01-03 Online:2020-07-26 Published:2020-07-28

Abstract: Biosynthesis of polyhydroxybutyrate(PHB)in Escherichia coli can be achieved by the overexpression of the operon phaCAB. Improving strain performance is regarded as the one of the key factors to lower the cost of PHB bio-production. An E. coli mutant S17-3,when having synthetized plasmid pBhya-CAB of expressing PHB,is able to grow at high density,and the maximal OD600 reached about 40 when growing in shake flasks. Comparative analysis of whole-genome scan sequencing and transcriptome sequencing revealed that mutations in reading frame sequence or at transcription level occurred in the carbon metabolic flux-related proteins,such as pgi of encoding phosphoglucose isomerase and zwf of encoding glucose-6-phosphate 1-dehydrogenase. Null deletion of zwf in S17-3 diminished the growth density of the strain,while pgi knockout in BW25113 promoted the transformant cells’ growth density. Therefore,it is revealed that the high-density growth of S17-3 is closely related to the optimization of itself carbon metabolic flux.

Key words: Escherichia coli, polyhydroxybutyrate, high-density growth, phosphoglucose isomerase, glucose-6-phosphate 1-dehydrogenase