Engineering central metabolic pathways for high-level flavonoid production in Escherichia coli

Appl Environ Microbiol. 2007 Jun;73(12):3877-86. doi: 10.1128/AEM.00200-07. Epub 2007 Apr 27.

Abstract

The identification of optimal genotypes that result in improved production of recombinant metabolites remains an engineering conundrum. In the present work, various strategies to reengineer central metabolism in Escherichia coli were explored for robust synthesis of flavanones, the common precursors of plant flavonoid secondary metabolites. Augmentation of the intracellular malonyl coenzyme A (malonyl-CoA) pool through the coordinated overexpression of four acetyl-CoA carboxylase (ACC) subunits from Photorhabdus luminescens (PlACC) under a constitutive promoter resulted in an increase in flavanone production up to 576%. Exploration of macromolecule complexes to optimize metabolic efficiency demonstrated that auxiliary expression of PlACC with biotin ligase from the same species (BirAPl) further elevated flavanone synthesis up to 1,166%. However, the coexpression of PlACC with Escherichia coli BirA (BirAEc) caused a marked decrease in flavanone production. Activity improvement was reconstituted with the coexpression of PlACC with a chimeric BirA consisting of the N terminus of BirAEc and the C terminus of BirAPl. In another approach, high levels of flavanone synthesis were achieved through the amplification of acetate assimilation pathways combined with the overexpression of ACC. Overall, the metabolic engineering of central metabolic pathways described in the present work increased the production of pinocembrin, naringenin, and eriodictyol in 36 h up to 1,379%, 183%, and 373%, respectively, over production with the strains expressing only the flavonoid pathway, which corresponded to 429 mg/liter, 119 mg/liter, and 52 mg/liter, respectively.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acetyl-CoA Carboxylase / metabolism
  • Carbon-Nitrogen Ligases / biosynthesis*
  • Carbon-Nitrogen Ligases / metabolism
  • DNA Primers / genetics
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / biosynthesis*
  • Escherichia coli Proteins / metabolism
  • Flavonoids / biosynthesis*
  • Gene Expression Regulation, Bacterial*
  • Genotype
  • Malonyl Coenzyme A / metabolism
  • Metabolic Networks and Pathways / genetics*
  • Molecular Structure
  • Protein Engineering
  • Repressor Proteins / biosynthesis*
  • Repressor Proteins / metabolism
  • Transcription Factors / biosynthesis*
  • Transcription Factors / metabolism

Substances

  • DNA Primers
  • Escherichia coli Proteins
  • Flavonoids
  • Repressor Proteins
  • Transcription Factors
  • Malonyl Coenzyme A
  • Carbon-Nitrogen Ligases
  • birA protein, E coli
  • Acetyl-CoA Carboxylase