Decorating outer membrane vesicles with organophosphorus hydrolase and cellulose binding domain for organophosphate pesticide degradation

Outer membrane vesicles (OMVs) are nanoscale spheres naturally released from Gram-negative bacteria. They contain a diverse array of proteins and lipopolysaccharide but do not replicate, which increases their safety profile and renders them attractive for environmental applications. Herein, an efficient and reusable biocatalyst for enhanced degradation of organophosphate pesticides was developed. Organophosphorus hydrolase (OPH) was tethered onto OMVs via a genetically fused ice nucleation protein (INP) to form OMV-based biocatalysts. To accomplish quick purification and easy recovery of the engineered OMV using cellulose, a cellulose binding module (CBM) was collaterally tethered on the OMV. The OPH-decorated OMVs exhibited an enhanced degradation rate when assayed with paraoxon as a substrate. In addition, the thermal stability and pH tolerance were also enhanced remarkably. Furthermore, the resulting biocatalysts could still retain more than 80% activity even after 15 cycles of recovery and reuse, demonstrating their potential use in bio-catalytic decontamination of organophosphate compounds. (C) 2016 Elsevier B.V. All rights reserved.