Simultaneous degradation of organophosphates and 4-substituted phenols by Stenotrophomonas species LZ-1 with surface-displayed organophosphorus hydrolase.

Organophosphorous hydrolase (OPH) was expressed onto the surface of a Stenotrophomonas species (LZ-1), capable of simultaneously degrading 4-substituted phenols, using the N- and C-terminal domains of ice nucleation protein (INPNC) as an anchoring motif for the first time. The engineered strain LZ-1 could degrade p-nitrophenyl-substituted organophosphates as well as their hydrolytic product, PNP, rapidly. Especially, addition of 4-CP (below 0.8 mM) significantly accelerated the complete degradation of above organophosphates (47.1, 34.0, and 40% reduction of time of paraoxon, parathion, and methyl-parathion, respectively) through the accelerated degradation of PNP due to enhanced cell growth supported by 4-CP as the carbon source. OPH could be surface-displayed at a high level without inhibition of cell growth and OPH activity in the presence of 4-CP. In soil samples, strain LZ-1 could also remove these compounds successfully. Functional display of heterologous proteins on the surface of indigenous bacteria could provide a promising technology for effective bioremediation of sites contaminated with mixed organic pollutants.