Identification of nitrile hydratase-producing Rhodococcus ruber TH and characterization of an amiE-negative mutant

Bioresour Technol. 2010 Jan;101(1):285-91. doi: 10.1016/j.biortech.2009.07.057. Epub 2009 Aug 31.


Microbial transformation of acrylonitrile to acrylamide by nitrile hydratase is of great interest to green chemistry. During the transformation, acrylic acid is generally accumulated as a by-product through biocatalysis of amidase. A novel strain with high nitrile hydratase activity was isolated from soil and identified as Rhodococcus ruber TH by morphology and 16S rRNA gene analysis. An amidase-negative recombinant, R. ruber TH3 was constructed. Its nitrile hydratase activity was 25% higher than that of the wild type, reaching 490+/-29.2U/mg dry cell weight, while the amidase activity was 60% lower. After 6 h hydration of acrylonitrile using free cells as biocatalysts at 18 degrees C, acrylamide production by TH3 was 23% higher and the production of the by-product, acrylic acid, was 87% lower than that of the wild type. This result demonstrates that the strain TH3 could be valuable for industrial applications.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amidohydrolases / genetics
  • Amidohydrolases / metabolism*
  • Gene Knockout Techniques
  • Hydro-Lyases / biosynthesis*
  • Mutation / genetics
  • Rhodococcus / genetics
  • Rhodococcus / isolation & purification*
  • Rhodococcus / metabolism*
  • Species Specificity


  • Amidohydrolases
  • amidase
  • Hydro-Lyases
  • nitrile hydratase