A Novel Cold-Active Glycerophosphodiester Phosphodiesterase and its Application in Whole-Cell Catalytic Degradation of Diphenyl Phosphate at Low Temperature

Abstract

As the organophosphate esters (OPEs), diphenyl phosphate (DPhP) had been detected in various environments. The key enzyme glycerophosphodiester phosphodiesterase (GDPD) for degrading DPhP, from Psychrobacter sp. NJ358 (named PsGDPD) was cloned and expressed. Subsequently, PsGDPD exhibited optimal activity at 25 °C and possessed cold-active structural characteristics. In order to break down the barrier of intracellular enzyme transport and broaden its application, the engineered bacteria BL21/pET-InaKN-PsGDPD with well outer membrane integrity was constructed through the novel ice nucleoprotein (INP) cell surface engineering. Then, engineered bacteria was made into whole-cell catalysts, maintaining 68.5% and 52.1% relative activity after 8 times catalytic cycles and 7 days storing at 10 °C. Notably, 0.5 mg L-1 DPhP was extracellularly degraded by the whole-cell catalysts at 10 °C after 48 h. Therefore, whole-cell catalysts made by BL21/pET-InaKN-PsGDPD offering a promising eco-friendly approach for the degradation of DPHP in low-temperature environments.

Keywords: OPEs, Low-temperature, Ice nucleoprotein, Whole-cell catalysts