Avneet Kaur2017-02-212017-02-212012http://krishikosh.egranth.ac.in/handle/1/5810001861For bioremediation of endosulfan, nine bacterial species isolated from sugarcane field soils and identified using 16S rDNA sequence homology. These could cause only partial endosulfan metabolization (maximum of 50.22%) coupled with appearance of toxic endosulfan sulphate as metabolite. Evaluation of earlier identified 15 bacterial species resulted in selection of Brevibacterium frigoritolerans, Bacillus alkalinitrilicus and Pseudomonas fulva causing 86.58, 81.30 and 71.58 % endosulfan reduction, respectively. These bacterial species could grow over a wide range of pH (4.0-11.0) and temperature (25-37°C), but optimally at pH of 6.0-6.5 and 37°C, though growth was more rapid in shake than stationary cultures. However, whereas, B. frigoritolerans was sensitive to high salt concentrations, P. fulva & B. alkalinitrilicus grew optimally at salt concentration of 3.0 and 4.0 %, respectively. Maximum endosulfan degradation by B. frigoritolerans and P. fulva was not affected by presence of additional carbon and/or nitrogen sources suggesting the endosulfan metabolization by these species to be inducible by endosulfan only. In case of B. alkalinitrilicus, improvement in endosulfan reduction by the presence of additional C and/or N sources (80.58 to 95.14%) established the constitutive nature of endosulfan degradation. Whereas B. alkalinitrilicus holds potential for bioremediation of endosulfan in nutrient enriched agricultural soils and sewage water, B. frigoritolerans and P. fulva could find equal exploitation for endosulfan degradation in nutrient deficit environments.ennullThesis