Simultaneous degradation of organophosphorus pesticides and p-nitrophenol by a genetically engineered Moraxella sp with surface-expressed organophosphorus hydrolase

Moraxella sp., a native soil organism that grows on p-nitrophenol (PNP), wa s genetically engineered for the simultaneous degradation of organophosphor us (OP) pesticides and p-nitrophenol (PNP). The truncated ice nucleation pr otein (INPNC) anchor was used to target the pesticide-hydrolyzing enzyme, o rganophosphorus hydrolase (OPH), onto the surface of Moraxella sp., allevia ting the potential substrate uptake limitation. A shuttle vector, pPNCO33, coding for INPNC-OPH was constructed and the translocation, surface display , and functionality of OPH were demonstrated in both E. coli and Moraxella sp. However, whole cell activity was 70-fold higher in Moraxella sp. than E . coli. The resulting Moraxella sp. degraded organophosphates as well as. P NP rapidly, all within 10 h. The initial hydrolysis rate was 0.6 mu mol/h/m g dry weight, 1.5 mu mol/h/mg dry weight, and 9.0 mu mol/h/mg dry weight fo r methyl parathion, parathion, and paraoxon, respectively. The possibility of rapidly degrading OP pesticides and their byproducts should open up new opportunities for improved remediation of OP nerve agents in the future. (C ) 2001 John WIley & Sons, Inc.