title: Specific adhesion to cellulose and hydrolysis of organophosphate nerve agents by a genetically engineered Escherichia coli strain with a surface-expressed cellulose-binding domain and organophosphorus hydrolase.
abstract: A genetically engineered Escherichia coli cell expressing both organophosphorus hydrolase (OPH) and a cellulose-binding domain (CBD) on the cell surface was constructed, enabling the simultaneous hydrolysis of organophosphate nerve agents and immobilization via specific adsorption to cellulose. OPH was displayed on the cell surface by use of the truncated ice nucleation protein (INPNC) fusion system, while the CBD was surface anchored by the Lpp-OmpA fusion system. Production of both INPNC-OPH and Lpp-OmpA-CBD fusion proteins was verified by immunoblotting, and the surface localization of OPH and the CBD was confirmed by immunofluorescence microscopy. Whole-cell immobilization with the surface-anchored CBD was very specific, forming essentially a monolayer of cells on different supports, as shown by electron micrographs. Optimal levels of OPH activity and binding affinity to cellulose supports were achieved by investigating expression under different induction levels. Immobilized cells degraded paraoxon rapidly at an initial rate of 0.65 mM/min/g of cells (dry weight) and retained almost 100% efficiency over a period of 45 days. Owing to its superior degradation capacity and affinity to cellulose, this immobilized-cell system should be an attractive alternative for large-scale detoxification of organophosphate nerve agents.
authors.affiliation: Department of Chemical and Environmental Engineering, Environmental Toxicology Graduate Program, University of California, Riverside, California 92521, USA.
authors.forename: Aijun A
authors.initials: AA
authors.lastname: Wang
authors.forename: Ashok
authors.initials: A
authors.lastname: Mulchandani
authors.forename: Wilfred
authors.initials: W
authors.lastname: Chen
mesh_terms: D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D018914:Cells, Immobilized; D002482:Cellulose / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D015964:Gene Expression Regulation, Bacterial; D005818:Genetic Engineering / Q000379:methods*; D006868:Hydrolysis; D007306:Insecticides / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D009943:Organophosphorus Compounds / Q000378:metabolism*; D010261:Paraoxon / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D007306:Insecticides; D009943:Organophosphorus Compounds; D011993:Recombinant Fusion Proteins; D002482:Cellulose; C045290:phosphorylphosphatase; D010744:Phosphoric Monoester Hydrolases; D010261:Paraoxon