Rai, J.P.NPant, Apourv2019-02-092019-02-092018-01http://krishikosh.egranth.ac.in/handle/1/5810094270Biodegradation study of organophosphate chlorpyrifos (CP) by two potential soil bacterial isolates was investigated under controlled laboratory conditions. The two strains, named as AP1 and AP2, based on cultural, morphological, biochemical and16s RNA profiling were identified as Pseudomonas aeruginosa and Bacillus pumilus, respectively. Initial concentration 200mg/l of CP was supplemented in minimal salt broth medium for checking the biodegradation potential at pH 6.5, 7.0, 7.5 and temperatures 25°C, 30° and 35°C. The CP biodegradation was slow, initially for first 5-10 days and later on accelerated. The CP degradation potential of Pseudomonas aeruginosa and Bacillus pumilus was strongly influenced by pH and temperature with maximum degradation at pH 7.0 and temperature 30°C followed by pH 7.5 and 35°C at the end of 20 days. Lowest CP degradation was observed at pH 6.5 and 25°C temperature. The optimal conditions for both isolates were pH 7.0 and 35°C temperature. At the end of 20 days 86.6% and 84.72% CP was degraded by Pseudomonas aeruginosa and Bacillus pumilus respectively at optimum pH of 7.0 and 30°C temperature. Further the study was elaborated by constructing a pilot scale biphasic bioslurry bioreactor (BBBS) and its optimization was done following Taguchi’s Design of Experiment Methodology (DOE). Six factors, which significantly influence the performance of the two phase bioslurry reactor were considered, viz., substrate-loading rate(SLR), slurry phase pH, DO of soil mixture, soil water ratio, operating temperature and soil microflora (as CFU). Among which DO of soil mixture was found to be the most important factor influencing the biodegradation process. The optimum operating conditions obtained from the methodology showed enhanced chlorpyrifos degradation from 283.86 μg/g to 955.364 μg/g by overall 70.34% of enhancement in biodegradation. This study clearly demonstrated that Pseudomonas aeruginosa AP1 and Bacillus pumilus AP2 were able to metabolize CP efficiently and thus could be employed in a sustainable way for field scale bioremediation of CP and alike chemicals.ennullThesis