Applied Microbiology and Biotechnology

, Volume 87, Issue 6, pp 2247–2256

Production of polyhydroxyalkanoates by Escherichia coli mutants with defected mixed acid fermentation pathways

Authors

  • Jia Jian
    • Protein Science Laboratory of the Ministry of Education, Department of Biology, School of Life SciencesTsinghua University
  • Shao-Qin Zhang
    • Protein Science Laboratory of the Ministry of Education, Department of Biology, School of Life SciencesTsinghua University
  • Zhen-Yu Shi
    • Department of ChemistryUniversity of Melbourne
  • Wei Wang
    • Life Science Division, Graduate School at ShenzhenTsinghua University
    • Protein Science Laboratory of the Ministry of Education, Department of Biology, School of Life SciencesTsinghua University
    • Protein Science Laboratory of the Ministry of Education, Department of Biology, School of Life SciencesTsinghua University
Applied Microbial and Cell Physiology

DOI: 10.1007/s00253-010-2706-0

Cite this article as:
Jian, J., Zhang, S., Shi, Z. et al. Appl Microbiol Biotechnol (2010) 87: 2247. doi:10.1007/s00253-010-2706-0

Abstract

A series of Escherichia coli BW25113 mutants with reduced mixed acid fermentation were constructed. Genes ackA-pta, poxB, ldhA, adhE, and pflB encoding acetate kinase, phosphate acetyltransferase, pyruvate oxidase, d-lactate dehydrogenase, acetaldehyde dehydrogenase, and pyruvate formate-lyase, respectively, were deleted successively. When grown under microaerobic condition, the mutants reduced approximately 90% acetate excretion after the deletion of genes ackA-pta and poxB. Production of lactate, ethanol, and formate was also significantly reduced after the deletion of genes ldhA, adhE, and pflB, respectively. The accumulation of biomass and poly(3-hydroxybutyrate) (PHB) were significantly enhanced after deleting the mixed acid fermentation. E. coli mutant BWapld with deletions of ackA-pta, poxB, ldhA, and adhE produced twice the cell dry weight (CDW) and 3.5 times of PHB compared with its wild-type under microaerobic conditions. E. coli mutant BWapl with deletions of ackA-pta, poxB, and ldhA also achieved nearly twice CDW and three times of PHB content in comparison to the wild-type during 48 h static cultivation. Production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] was observed in the mutants under static cultivation. E. coli mutant BWapld could produce approximately 50 wt.% P(3HB-co-3HV) consisting of 5 mol% of 3-hydroxyvalerate (3HV) under aerobic conditions, when the seed culture was inoculated at an appropriate time. When ackA-pta, poxB, ldhA, adhE, and pflB were deleted, E. coli mutant BWapldf accumulated over 70 wt.% P(3HB-co-3HV) consisting of 8 mol% 3HV under aerobic conditions.

Keywords

PHBP(3HB-co-3HV)Escherichia coliPolyhydroxyalkanoatesMixed acid fermentationMetabolic engineering

Copyright information

© Springer-Verlag 2010