title: Biodegradation of organophosphate pesticide using recombinant Cyanobacteria with surface- and intracellular-expressed organophosphorus hydrolase.
abstract: The opd gene, encoding organophosphorus hydrolase (OPH) from Flavobacterium sp. capable of degrading a wide range of organophosphate pesticides, was surface- and intracellular-expressed in Synechococcus PCC7942, a prime example of photoautotrophic cyanobacteria. OPH was displayed on the cyanobacterial cell surface using the truncated ice nucleation protein as an anchoring motif. A minor fraction of OPH was displayed onto the outermost surface of cyanobacterial cells, as verified by immunostaining visualized under confocal laser scanning microscopy and OPH activity analysis; however, a substantial fraction of OPH was buried in the cell wall, as demonstrated by proteinase K and lysozyme treatments. The cyanobacterial outer membrane acts as a substrate (paraoxon) diffusion barrier affecting whole-cell biodegradation efficiency. After freeze-thaw treatment, permeabilized whole cells with intracellular-expressed OPH exhibited 14-fold higher bioconversion efficiency (Vmax/Km) than that of cells with surface-expressed OPH. As cyanobacteria have simple growth requirements and are inexpensive to maintain, expression of OPH in cyanobacteria may lead to the development of a lowcost and low-maintenance biocatalyst that is useful for detoxification of organophosphate pesticides.
authors.affiliation: Institute of Molecular Biology and Genetics, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand. stwcj@mucc.mahidol.ac.th
authors.forename: Wipa
authors.initials: W
authors.lastname: Chungjatupornchai
authors.forename: Sirirat
authors.initials: S
authors.lastname: Fa-Aroonsawat
mesh_terms: D043303:Aryldialkylphosphatase / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019286:Endopeptidase K / Q000378:metabolism; D005417:Flavobacterium / Q000201:enzymology; D015870:Gene Expression; D007700:Kinetics; D009113:Muramidase / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000378:metabolism*; D010575:Pesticides / Q000378:metabolism*; D015202:Protein Engineering; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D046940:Synechococcus / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D009943:Organophosphorus Compounds; D010575:Pesticides; D011994:Recombinant Proteins; D043303:Aryldialkylphosphatase; D009113:Muramidase; D019286:Endopeptidase K