Enhancement of MBBR reactor efficiency using effective microorganism for treatment of wastewater containing diazinon by engineered Pseudomonas putida KT2440 with manganese peroxidase 2 gene

Pesticides not only are harmful to humans but they are noxious for water reservoirs, soil, and air quality as well. In this research, diazinon was removed from aqueous solutions by Moving Bed Biofilm Reactor (MBBR). The MBBR was spiked with transgenic Pseudomonas putida KT2440 with Pleurotus ostreatus fungus manganese peroxidase 2 gene to enhance the capabilities of Pseudomonas putida KT2440 in the degradation of diazinon. Although the amount of diazinon and COD and diazinon removal in the reactor including transgenic P. putida KT2440 was 95.46% and 97.47% and they were greater than the control and wild type (non-modified) P. putida KT2440 reactors, the surprising result was related to the adaptation pace of transgenic P. putida KT2440. The produced metabolites and the quantity of diazinon were assessed by HPLC and LC/MS. The metabolite hydroxyisopropyl diazinon was not found in the transgenic P. putida KT2440 reactor. Furthermore, a new sequence of cloned manganese peroxidase 2 gene has been recorded in GenBank with the accession number MT185558. According to bacterial identification of provided sludge the most frequent genus belonged to Aeromonas . Therefore, it seems that the MBBR in the presence of transgenic P. putida KT2440 with manganese peroxidase 2 gene can effectively remove the diazinon. • Introducing new sequence of manganese peroxidase 2 gene from Pleurotus ostreatus . • Successful gene expression in Pseudomonas putida KT2440 bacteria. • Rapid removal of diazinon and COD by transgenic P. putida KT2440 in MBBR. • Considerable stability of transgenic P. putida KT2440 in biofilms. • Elimination of hydroxyisopropyl diazinon metabolite by transgenic P. putida in MBBR.