Gram-scale fermentative production of ergothioneine driven by overproduction of cysteine in Escherichia coli

Sci Rep. 2019 Feb 13;9(1):1895. doi: 10.1038/s41598-018-38382-w.

Abstract

Ergothioneine (ERG), a unique thiol compound, is suggested to function as an antioxidant and cytoprotectant. Despite several recent attempts to produce ERG using various organisms, its yield was still very low and the costs remained high. Since the level of ERG produced depends strictly on the availability of three distinct precursor amino acids (L-cysteine (Cys), L-histidine, and L-methionine (Met)), metabolic engineering for enhancement of the flux toward ERG biosynthesis is required. Herein, we took advantage of a high-Cys production system using Escherichia coli cells, in which Cys biosynthesis and excretion were activated, and applied it to the fermentative production of ERG from glucose. The Cys overproduction in E. coli cells carrying the egtBCDE genes from Mycobacterium smegmatis was effective for ERG production. Furthermore, coexpression of the egtA gene, which encodes γ-glutamylcysteine synthetase that synthesizes the γ-glutamylcysteine used as a sulfur source of ERG biosynthesis, enhanced ERG production even though E. coli intrinsically has γ-glutamylcysteine synthetase. Additionally, disruption of the metJ gene that encodes the transcriptional repressor involved in Met metabolism was effective in further increasing the production of ERG. Finally, we succeeded in the high-level production of 1.31 g/L ERG in a fed-batch culture process using a jar fermenter.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoproteins / genetics
  • Bacterial Proteins / genetics
  • Batch Cell Culture Techniques
  • Cysteine / biosynthesis*
  • Ergothioneine / biosynthesis*
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / genetics
  • Glucose / metabolism
  • Glutamate-Cysteine Ligase / genetics
  • Histidine / metabolism
  • Metabolic Engineering
  • Methionine / metabolism
  • Mycobacterium smegmatis / genetics
  • Repressor Proteins / genetics

Substances

  • Apoproteins
  • Bacterial Proteins
  • Escherichia coli Proteins
  • MetJ protein, E coli
  • Repressor Proteins
  • Histidine
  • Methionine
  • Ergothioneine
  • Glutamate-Cysteine Ligase
  • Glucose
  • Cysteine