Enhancement of diazinon degradation and chemical analysis of metabolites

IN THIS study, Pseudomonas aeruginosa strain GH2NO8 showed effective activity in Diazinon degradation. This bacterial strain was able to degrade 38.19 of Diazinon as compared to 1.83% in control media after 5 days. oph gene that encodes a protein involved in Diazinon hydrolysis was isolated and sequenced.

It is a member of the MBL-fold metallo hydrolase superfamily and has beta lactamase fold. Moreover, it has 99% similarity with that of Pseudomonas aeruginosa strain FDAARGOS. Partial DNA sequence of oph gene was depositedin Genbank database under accession number MF443870. PAM8 and PAMS9 were the best mutants in Diazinon biodegradation after ethylmethane sulphonate (EMS) mutation induction for Pseudomonas aeruginosa strain GH2NO8 resulted from first step and second step EMS mutation induction, respectively. PAM8 was able to degrade 62.19 of diazinon as compared to 38.19 % in wild type after 5 days.

However PAMS9 exhibited the ability to degrade 86.21% %. 2-Iso-4-methyl-6- hydroxypyrimidine (IMHP) was detected as the main degradation product of diazinon through GC/MS analysis after 10 days of incubation which was further metabolized to unknown polar metabolites. High Diazinon tolerance and degradation capability of the Pseudomonas aeruginosa strain GH2NO8 and its higher mutants make these strains suitable for decontamination and bioremediation of pesticides contaminated sites.