Efficient biodegradation of dihalogenated benzonitrile herbicides by recombinant Escherichia coli harboring nitrile hydratase-amidase pathway

摘要: Abstract Worldwide use of benzonitrile herbicides has caused a contamination hazard for groundwater, and their removal attracted increasing attention. Microbial degradation been considered as major route removing toxic nitriles from the environment. However, process is very inefficient degrading by natural microbes. In this study, recombinant microbial cell was constructed to degrade co-expression nitrile hydratase amidase in Escherichia coli. Both enzymes were functionally over-expressed cytoplasm E. The NHase activities reactor on dichlobenil ioxynil 15.4 21.3 U/mg dry weigh (DCW), respectively. And 2,6-dichlorobenzamide 3,5-iodo-4-hydroxybenzamide 8.3 13.6 U/mg DCW, Furthermore, investigated using reactor. suggested that degraded corresponding carboxylic acids via hydratase-amidase pathway, intermediate amides (2,6-dichlorobenzamide 3,5-iodo-4-hydroxybenzamide) did not accumulate reaction mixture. rates 43 185 mg/g DCW/h, coli observed be promising catalysts bioremediation wastewater containing herbicides.