Expression of organophosphorus hydrolase in Escherichia coli for use as whole-cell biocatalyst

Among the various removal strategies against neurotoxic organophosphorus (OP) compounds, a live catalyst using whole-cell microorganisms has been considered as a useful scavenger with the virtue of cost-effectiveness and elimination efficiency. To over the catalytic activity by wild-type isolates, the expression of organophosphorus hydrolase (OPH) has been attempted in Escherichia coli for the extended detoxification efficacy to OP chemicals. However, early studies had unsatisfactory results, like low enzyme production levels due to the formation of insoluble inclusion bodies from the recombinant enzyme produced within the cells, and a bottleneck caused by the cell membrane of gram-negative strain E. coli acting as a permeability barrier to substrate diffusions. To date, various approaches have been suggested as effective solutions for overcoming these limits. This review will outline current studies, and their critical findings, on the successful expression of OPH in E. coli for the effective recombinant E. coli whole-cell biocatalysts.