Utilization of monocrotophos as phosphorus source by Pseudomonas aeruginosa F10B and Clavibacter michiganense subsp. insidiosum SBL 11.
Monocrotophos (dimethyl (E)-1-methyl-2-(methylcarbamoyl) vinyl phosphate, or MCP), an organophosphorus insecticide, was used as a sole phosphorus source by the microorganisms isolated from the soil. None of the isolates could utilize MCP as a sole source of carbon. Two of the potential microbial isolates, Pseudomonas aeruginosa F10B and Clavibacter michiganense subsp. insidiosum SBL 11, could utilize MCP as a sole source of phosphorus. Pseudomonas aeruginosa F10B showed a lag phase of 4 h, while in the case of C. michiganense subsp. insidiosum SBL 11, it was 8 h when cultured in the presence of MCP. The generation time for both strains was increased in the medium containing MCP. It was 2.15 h for P. aeruginosa F10B in MCP medium as compared with 1.29 h in basal medium, while in case of C. michiganense subsp. insidiosum SBL 11 it was increased to 3.4 h in MCP medium as compared with 1.28 h in basal medium. These two strains were able to degrade technical MCP in shake-flask culture up to 98.9 and 86.9%, respectively, and pure MCP up to 79 and 80%, respectively, within 24 h at 37 degrees C. The optimal concentration of MCP required for the normal growth was 500 ppm. In the substrate preference study, Tris-p-nitrophenyl phosphate was the most preferred substrate followed by paraoxon. The enzyme responsible for the break down of MCP was phosphotriesterase, which was localized on the membrane-bound fraction of the disrupted cells. The gene responsible for the production of phosphotriesterase (opd) in P. aeruginosa F10B was plasmid-borne.
Singh
Subhas
S
Department of Zoology, University of Delhi, Delhi 110007, India.
Singh
Dileep Kumar
DK
D000192:Actinomycetales / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D043303:Aryldialkylphosphatase; D003470:Culture Media; D004950:Esterases / Q000032:analysis / Q000096:biosynthesis; D008999:Monocrotophos / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D013696:Temperature; D013997:Time Factors
D003470:Culture Media; D010758:Phosphorus; D008999:Monocrotophos; D004950:Esterases; D043303:Aryldialkylphosphatase