Whole-cell Catalytic Activity of Nitrile Hydratase on Nitrile Compounds Derived from Comamonas testosteroni 5-MGAM-4D

Objective:Constructed the gene recombinant E. coli CtNHase which expressed nitrile hydratase efficiently by gene cloning technology,then investigated its biocatalytic activity of nitriles and the effects of pH and temperature with the whole cell catalytic reaction. Methods:The nitrile hydratase gene of Commamonas testosteroni 5-MGAM-4D was amplified by polymerase chain reaction(PCR),the recombinant expression plasmid was constructed with pET-24a vector. After transformed into competent E. coli cells,the expression of protein was verified by SDS-PAGE. The conversion of the substrates of acrylonitrile and adiponitrile were analyzed by chromatography. Results:According to the whole cell catalysis,we found the recombinant E. coli CtNHase transformed 50 mmol/L adipiconitrile to adipamide in 5 min completely,while transformed 500 mmol/L acrylonitrile to acrylamide in 5 h. The optimum pH and reaction tempreture were 7.4,30 ℃,the E. coli exhibited the highest catalytic activity. Conclusion:The recombinant E. coli CtNHase could catalyze acrylonitrile and adiponitrile to acrylamide and adipamide high efficiently,which would show the potential industrial application prospects.