title: Parathion utilization by bacterial symbionts in a chemostat.
abstract: A continuous-culture device was used to select and enrich for microorganisms, from sewage and agricultural runoff, that were capable of using the organophosphorus insecticide parathion as a sole growth substrate. Parathion was dissimilated by the highly acclimated symbiotic activities of Pseudomonas stutzeri, which non-oxidatively and cometabolically hydrolyzed the parathion to ionic diethyl thiophosphate and p-nitrophenol, and P. aeruginosa, which utilized the p-nitrophenol as a sole carbon and energy source. Ionic diethyl thiophosphate was found to be inert to any transformations. Methyl parathion was dissimilated in an analogous way. The device functioned as a chemostat with parathion as the growth-limiting nutrient, and extraordinarily high dissimilation rates were attained for parathion (8 g/liter per day) and for p-nitrophenol (7 g/liter per day). This is the first report of parathion utilization by a defined microbial culture and by symbiotic microbial attack and of dissimilation of an organophosphorus pesticide in a chemostat.
mesh_terms: D006868:Hydrolysis; D009596:Nitrophenols / Q000378:metabolism; D009946:Organothiophosphorus Compounds / Q000378:metabolism; D010278:Parathion / Q000378:metabolism*; D011549:Pseudomonas / Q000254:growth & development / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000254:growth & development / Q000378:metabolism*; D012722:Sewage; D013559:Symbiosis; D014871:Water Microbiology
chemical_list: D009596:Nitrophenols; D009946:Organothiophosphorus Compounds; D012722:Sewage; D010278:Parathion