Goyal, SnehPooja2017-09-222017-09-222017http://krishikosh.egranth.ac.in/handle/1/5810031702Imidacloprid, a chloronicotinyl insecticide is used in various crops like, cotton, rice, cereal, maize, sunflowers, potatoes and vegetables for the control of biting and sucking insects, including rice hoppers, aphids, thrips, whiteflies, termites, turf insects. So, there is strong need to remediate imidacloprid. The best method used is bioremediation using microorganisms mainly because of its eco-friendliness and cost effectiveness. During the present investigation, thirty one mutually morphologically distinct bacterial isolates were obtained from imidacloprid contaminated soil samples from Jalalpur kalan village and HAU fields by enrichment culture technique. Eight bacterial isolates showed growth up to 30,000 ppm imidacloprid amended in Mineral salt medium (MSM) containing glucose (0.2%). Out of eight, four isolates showing good growth onMSM agar plates containing 30,000 ppm of imidacloprid were selected for different carbon and nitrogen source utilization pattern on MSM agar plates. All the isolates showed good growth in presence of five different carbon and nitrogen sources. Therefore, these carbon and nitrogen sources were selected for imidacloprid utilization in MSM.More bacterial count and protein content was observed in the medium amended with glucose as carbon source and ammonium chloride as nitrogen source as compared to medium amended with other carbon and nitrogen sources with all the four isolates. To study the utilization of imidacloprid in liquid medium (containing glucose and ammonium chloride), medium was amended with 100 ppm imidacloprid. After 7 days of growth, residual imidacloprid was determined in the medium. Maximum utilization of imidacloprid was found with the isolate IP5 (83%) followed by IP1 (82.2 %), IP6 (74.5%) and IP7 (55.1%) respectively. Growth of four selected isolates was studied in sterilized as well as unsterilized soil amended with imidacloprid (100 ppm) for a period of two months under laboratory conditions. Viable count was higher in imidacloprid amended soil as compared to unamended soil with all the isolates. Imidacloprid level decreased in all the treatments. Percent degradation of imidacloprid was found more in unsterilized soil as compared to sterilized soil. Maximum utilization of imidacloprid was found with the isolate IP5 (76.0 %) followed by IP1 (73.0 %), IP6 (72.0%) and IP7 (57%) in sterilized soil. Similar trend was observed in unsterilized soil i.e. maximum utilization of imidacloprid with the isolate IP5 (82.2 %) followed by IP1 (80.9 %), IP6 (77.27%) and IP7 (68.34 %) respectively. A pot experiment was conducted to evaluate the potential of the two imidacloprid utilizing bacterial isolates IP1 and IP5 in the presence of cotton plants under natural conditions. Germination of seeds was not observed in the treatments amended with 200 ppm imidacloprid. Shoot and root growth was found to be significantly higher in the inoculated treatments amended with 50-100 ppm imidacloprid as compared to their respective uninoculated treatments. Significant decrease in imidacloprid content was observed in soil on inoculation with bacterial isolates. Promising isolates were identified on the basis of 16 s rDNA gene sequencing. Bacterial isolate IP1 was found to be most similar to Bacillus pumilus strain NFB1 and IP5 was found to be most similar to Bacillus aryabhattai.ennullThesis