School Of Environment And Earth Sciences

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    Chlorpyrifos degrading potential of a Bacterial isolate from Thermal Power Plant Soil
    (World Research Association, 2023-01-27T00:00:00) Dubey, Sheetal; Dhanya, M.S.
    The pesticides had a significant role in crop protection and in agricultural production. The organophosphate pesticides are used against many crop pests. But the injudicious application results in residues of organophosphate pesticides in soil routed to food chain by different means and affect the human health. There is a great need for remediation of the toxic residues from the environment. The microbial bioremediation is a safe and eco-friendly technique for pesticide removal. The present study focused on the degradation ability of a bacterium previously isolated from the soil contaminated with fly ash from coal based thermal power plant. The 16S rRNA sequencing confirmed the bacterium as Lysinibacillus fusiformis. The chlorpyrifos utilization capability of the isolated bacterium was studied in mineral salt medium supplemented with 50 mg L-1 chlorpyrifos as sole carbon source at 30oC and 120 rpm for 15 days. The bacterium was able to grow in the medium with the production of alkaline phosphatase and reduction in pH of the growth media. The bacterium degraded 16.54 percent of chlorpyrifos in 15 days. The chlorpyrifos utilization for bacterial biomass production confirmed the in situ biodegradation ability of the bacterium. � 2023 World Research Association. All rights reserved.
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    Chlorpyrifos Degradation in Semi-Arid Soil by Pseudomonas fluorescens Strain CD5 Isolated from Manured Soil
    (Taylor and Francis Ltd., 2022-07-19T00:00:00) Dubey, S.; Dhanya, M.S.
    The present paper focused on investigating the potential of indigenous Pseudomonas fluorescens strain CD5 isolated from manure-enriched soil as a bioremediation agent for chlorpyrifos biodegradation in semi-arid soil of Bathinda district of Punjab, India. The soil had sandy loam texture with slightly alkaline pH and low organic matter content of 0.36%. The growth pattern, alkaline phosphatase enzyme production and chlorpyrifos utilization capability of Pseudomonas fluorescens strain CD5 were screened in mineral salt medium and the results revealed degradation of 78.19% of 500 mg L?1 chlorpyrifos within 15�days. The pattern of chlorpyrifos degradation was further studied in natural conditions of semi-arid soil by the Pseudomonas fluorescens strain CD5 and photolysis by sunlight for a period of 105�days. The biodegradation of chlorpyrifos at 500 mg kg?1 sterile soil by Pseudomonas fluorescens strain CD5 was 59.68% in comparison to 26% of photodegradation and enhancing total degradation. The residual chlorpyrifos in sterile soil after biodegradation by Pseudomonas fluorescens strain CD5 under natural light condition was 14.33%. The alkaline phosphatase enzyme activity in soil was found positively correlated with the chlorpyrifos degradation. The Pseudomonas fluorescens strain CD5 can be an effective candidate for the bioremediation of chlorpyrifos-contaminated soil. � 2022 Taylor & Francis.
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    Amino-functionalized Magnetic Iron Nanoparticles As a Carrier for Laccase Enzyme and Its Potential to Degrade Chlorpyrifos in Contaminated Soil: Fate and Kinetics
    (Springer Science and Business Media Deutschland GmbH, 2022-04-14T00:00:00) Das, Anamika; Yogalakshmi, Kn
    The present study utilizes the covalent-crosslinking method to immobilize the�laccase enzyme on magnetic iron nanoparticles�and further assess its potential in degrading�chlorpyrifos in pesticide spiked�soil. The soil texture analysis revealed the presence of clay, silt and sand accounting to�7.1%, 14.3%, and 78.6%, respectively. The degradation of chlorpyrifos in spiked soil�using laccase enzyme�immobilized�magnetic iron nanoparticles was measured for 60�days�in a batch process. The results revealed a gradual increase in degradation efficiency showing around�29.3%, 43.8%, 56.3%, and 67.3% at the 20th, 30th, 40th, and 50th day�of incubation. A maximum degradation of�83.6% was observed on the 60th day of incubation. Intermediate products 2,4-bis(1,1 dimethylethyl) phenol, 1,2 benzenedicarboxylic acid, bis(2-methyl propyl) ester�and�piperidine confirmed the degradation of chlorpyrifos in soil. The piperidine originated in the chromatogram between�20�40�days of incubation and diminished later. Chlorpyrifos degradation followed pseudo first-order kinetics with a R2 of 0.96. Further, the nanoparticles showed no negative�impact on soil bacterial population during the antibacterial assay. The study confirms the degradation of chlorpyrifos in contaminated soil using laccase-immobilized nanoparticles. � 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
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    Degradation of chlorpyrifos in soil using laccase immobilized iron oxide nanoparticles and their competent role in deterring the mobility of chlorpyrifos
    (Elsevier Ltd, 2020) Das A.; Jaswal V.; Yogalakshmi K.N.
    Covalent-immobilization of the laccase enzyme onto the iron oxide nanoparticles was achieved using N-(3-Dimethylaminopropyl)-N?-ethylcarbodiimide hydrochloride (EDAC) as cross-linkers. The presence of sulphur moeity in the laccase immobilized nanoparticles (LNPs) observed through Scanning Electron Microscopy- Energy dispersive X-ray spectroscopy (SEM-EDS) spectra confirmed the immobilization of laccase enzyme. The TEM analysis of iron oxide nanoparticles (FNPs), chitosan coated iron nanoparticles (CNPs) and laccase immobilized nanoparticles (LNPs) confirmed their sizes around 12, 15 and 20 nm, respectively. The effect of LNPs in degrading chlorpyrifos under field conditions was studied by simulating the conditions in a column. Column A, which was used as control showed more leaching of chlorpyrifos as compared to column B containing LNPs. The sorption coefficient (Kd) value obtained for control (column A) and LNPs containing column B were 21.6 and 112.3 L/kg, respectively. LNPs altered the Kd values of soil thereby showing lesser leaching potential. Higher the Kd value, lesser will be the leaching potential in the ground water. Copper in laccase enzyme resulted in hydrolysis of chlorpyrifos. Chitosan used for coating on FNPs and soil organic matter resulted in the adsoption of chlorpyrifos. Current results will allow a better assessment of the role of LNPs as a competent deterrent in chlorpyrifos mobility and degradation.