Improved stress tolerance of recombinant Escherichia coli strain expressing nitrile hydratase by combining Global Regulator IrrE

5-cyanopentanamide (5-CVAM) is an important intermediate for fine chemicals and pesticides. Previously, our group found a novel nitrile hydratase (ReNhase) that can convert adiponitrile (ADN) into 5-CVAM. Nevertheless, the poor tolerance of recombinant Escherichia coli (E. coli) strain has caused limitations in industrial applications. Herein, the tolerance of recombinant E. coli cells expressing ReNhase was explored by combining the IrrE gene, which is a representative global regulator derived from Deinococcus radiodurans. Results show that the tolerance of the modified strains was improved significantly with organic solvent. ReNhase TAC strain and ReNhase AmpRp strain were 2.8 times and 2.3 times higher than that of ReNhase WT strain in the yield of 5-CVAM. Meanwhile, the modified strains have outstanding performance in acid -base tolerance, thermal stability and tolerance in high salt solution. It is also found that the modified strains had smaller changes in mitochondrial membrane potential under the pressure environments described above. In terms of cell surface hydrophobicity, the modified strains had lower adsorption rates for organic solvents, which further confirmed the excellent tolerance of modified strains. The findings will provide a new theoretical basis for the modification of recombinant E. coli for improving the catalytic efficiency of adiponitrile in industrial production.