Sayali R. Naphade, Annika A. Durve, Meeta Bhot, Jossy Varghese and Naresh Chandra
The application of pesticides for pest control is a general practice in India. Since pesticides are very toxic by design, they have the potential to adversely impact the health of our ecosystem. However, there are few soil bacteria which can tolerate high concentrations of pesticides that may ultimately lead to degradation of pesticides. The main objective of the present study involved the isolation and identification of bacteria from garden soil, which can tolerate higher concentrations of pesticides namely Endosulfan,Chlorpyrifos and Cypermethrin. An enrichment culture technique was used to isolate 10 bacterial strains named EC1, EC2, EC3, EC4, EC5, EC6, EC7, EC8, EC9 and EC10, which were subsequently characterized by 16S rRNA gene sequencing and biochemical tests. The optimum temperature, pH and NaCl concentration was determined for all the isolates and it was found that EC8 was showing growth at wide range of these parameters. Growth curve experiments showed that the bacterial isolates were able to grow in a medium containing higher concentration of individual pesticide. Tolerance to high levels of metal salts (Co2+, Ni2+, Cr3+, Cu2+ and Mn2+) and multiple antibiotic resistances was seen in many of the bacterial isolates, which may indicate a positive correlation between pesticide degradation and tolerance to metals and antibiotics. Such findings may be useful in designing in-situ or on-site hazardous waste bioremediation process for field application.
