Overexpression of endogenous multi-copper oxidases mcoA and mcoC in Rhodococcus jostii RHA1 enhances lignin bioconversion to 2,4-pyridine-dicarboxylic acid

Biotechnol Bioeng. 2024 Apr;121(4):1366-1370. doi: 10.1002/bit.28620. Epub 2023 Dec 11.

Abstract

To improve the titre of lignin-derived pyridine-dicarboxylic acid (PDCA) products in engineered Rhodococcus jostii RHA1 strains, plasmid-based overexpression of seven endogenous and exogenous lignin-degrading genes was tested. Overexpression of endogenous multi-copper oxidases mcoA, mcoB, and mcoC was found to enhance 2,4-PDCA production by 2.5-, 1.4-, and 3.5-fold, respectively, while overexpression of dye-decolorizing peroxidase dypB was found to enhance titre by 1.4-fold, and overexpression of Streptomyces viridosporus laccase enhanced titre by 1.3-fold. The genomic context of the R. jostii mcoA gene suggests involvement in 4-hydroxybenzoate utilization, which was consistent with enhanced whole cell biotransformation of 4-hydroxybenzoate by R. jostii pTipQC2-mcoA. These data support the role of multi-copper oxidases in bacterial lignin degradation, and provide an opportunity to enhance titres of lignin-derived bioproducts.

Keywords: Rhodococcus jostii RHA1; lignin degradation; multi‐copper oxidase.

MeSH terms

  • Lignin* / metabolism
  • Parabens*
  • Peroxidases / metabolism
  • Pyridines / metabolism
  • Rhodococcus* / genetics
  • Rhodococcus* / metabolism

Substances

  • 4-hydroxybenzoic acid
  • Lignin
  • Peroxidases
  • Pyridines
  • Parabens

Supplementary concepts

  • Rhodococcus jostii