Gupta, V. K.Jariyal, Monu2017-06-032017-06-032013http://krishikosh.egranth.ac.in/handle/1/5810016005Fifteen phorate metabolizing bacterial species isolated from sugarcane field soils were identified using 16SrDNA sequence homology. Based upon relative phorate degradation, Brevibacterium frigoritolerans, Bacillus aerophilus and Pseudomonas fulva were found to cause more than 98 per cent phorate reduction. 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, in shaking cultures. Whereas, B. frigoritolerans was salt sensitive, P. fulva & B. aerophilus grew optimally in 3.0 and 4.0 per cent NaCl, respectively. All the three bacterial species grew optimally in the presence of glucose and peptone (1.0 % each). Only B. aerophilus carried a plasmid of around 4 kbp, but curing of this plasmid did not affect the phorate degradation establishing that phorate degradation genes are borne on chromosomal DNA. Induction by phorate resulted in only nondifferentiating protein profiles in all the three bacterial species establishing that phorate degradation is a constitutive character. In soils amended with upto 300 mg kg -1 phorate, these bacterial species within 42 days actively metabolized phorate by between 89.81 and 95.62 per cent with maximum capacity shown by P. fulva. This phorate degradation was further improved to 98.31 per cent, by mixed cultures of all the three bacterial species which constituted most effective bioremediation consortia for significantly relieving soils from phorate residues. The investigations in this study has isolated three bacterial species and established their potential for active bioremediation of phorate both in liquid cultures and agricultural soils.enPhorate, Degradation, Bacterial species, SoilThesis