Engineering Escherichia coli to convert acetic acid to free fatty acids

Yi Xiao, Zhenhua Ruan, Zhiguo Liu, Stephen G. Wu, Arul M. Varman, Yan Liu, Yinjie J. Tang

Research output: Contribution to journalArticlepeer-review

38 Scopus citations

Abstract

Fatty acids (FAs) are promising precursors of advanced biofuels. This study investigated conversion of acetic acid (HAc) to FAs by an engineered Escherichia coli strain. We combined established genetic engineering strategies including overexpression of acs and tesA genes, and knockout of fadE in E. coli BL21, resulting in the production of ~1g/L FAs from acetic acid. The microbial conversion of HAc to FAs was achieved with ~20% of the theoretical yield. We cultured the engineered strain with HAc-rich liquid wastes, which yielded ~0.43g/L FAs using waste streams from dilute acid hydrolysis of lignocellulosic biomass and ~0.17g/L FAs using effluent from anaerobic-digested sewage sludge. 13C-isotopic experiments showed that the metabolism in our engineered strain had high carbon fluxes toward FAs synthesis and TCA cycle in a complex HAc medium. This proof-of-concept work demonstrates the possibility for coupling the waste treatment with the biosynthesis of advanced biofuel via genetically engineered microbial species.

Original languageEnglish (US)
Pages (from-to)60-69
Number of pages10
JournalBiochemical Engineering Journal
Volume76
DOIs
StatePublished - Jul 5 2013
Externally publishedYes

Keywords

  • Acs gene
  • Anaerobic-digested
  • C
  • Carbon flux
  • Lignocellulosic biomass

ASJC Scopus subject areas

  • Biotechnology
  • Environmental Engineering
  • Bioengineering
  • Biomedical Engineering

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