School Of Environment And Earth Sciences

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Subject: search.filters.subject.Pesticide

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    Biodegradation of monocrotophos by indigenous soil bacterial isolates in the presence of humic acid, Fe (III) and Cu (II) ions
    (Elsevier Ltd, 2021-07-20T00:00:00) Singh, Simranjeet; Singh, Joginder; Ramamurthy, Praveen C.; Kumar, Vijay; Bhardwaj, Sonali; Garg, Vinod Kumar
    Three bacteria, namely Streptomyces sp. MCP1, Rhizobium leguminosarum MCP2 and Bacillus subtilis MCP3, isolated from an arable field, have been used for the biodegradation of monocrotophos (MCP). The bacterial strains were characterized based on the 16S rRNA gene sequence. MCP was subjected to biological degradation in two ways, i.e., with or without using Fe(III), Cu(II), and humic acid (HA). The isolates were capable of degrading MCP in an order: MCP2 (Bacillus subtilis) > MCP1 (Streptomyces sp.) > MCP3 (Rhizobium leguminosarum). With the application of Cu(II) and Fe(III), the biodegradation of MCP was from 83 to 92% and 78 to 87%, respectively. Altogether, under different conditions, the order of inhibition of MCP biodegradation was apparently as HA > Fe(III) > Cu(II). Mass spectrometric and UV�visible spectrophotometric results showed that MCP biodegradation's only pathway included major intermediatory metabolites (E) 4-amino-4-oxobut-2-en-2-yl dimethyl phosphate, dimethyl phosphate, methyl hydrogen phosphate and phosphonate. � 2021 Elsevier Ltd
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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.