Abstract
Methyl parathion (MP), a widely used organophosphorus (OP) pesticide, degrader was isolated from MP contaminated soil sample. It was identified as Arthrobacter globiformis AD26 on the basis of biochemical studies and 16s rRNA analysis. MP at a concentration of 1250 µg/mL was totally biodegraded by Arthrobacter globiformis AD26 as the sole carbon source at retention time (RT) for 72 hours on shaker. Cells grown in medium containing MP as sole carbon source, showed higher amount of protein, than the cells grown in presence of glucose as sole carbon source which was estimated by Biuret method. These results were confirmed by SDS-PAGE which showed induction of 97 kDa protein. P-nitrophenol (PNP), a hydrolysis product of MP, was also completely degraded by Arthrobacter globiformis AD26. This strain contained plasmid of approximately 47 kb size. Plasmid-curing experiments produced plasmid-free strain. This strain was unable to utilize MP demonstrating that the degradative genes for MP were located on the 47-kb plasmid.