Dutta Bhramar, Panja Anindya Sundar, Nigam Vinod Kumar, Nanjappan Satheesh Kumar, Ravichandiran Velayutham, Bandopadhyay Rajib
Department of Botany, The University of Burdwan, Purba Bardhaman, 713104, West Bengal, India.
Post-Graduate Department of Biotechnology and Biochemistry, Oriental Institute of Science and Technology, Vidyasagar University, Midnapore, 721102, West Bengal, India.
Sci Rep. 2024 Dec 28;14(1):30661. doi: 10.1038/s41598-024-73165-6.
The continuous exposure of chemical pesticides in agriculture, their contamination in soil and water pose serious threat to the environment. Current study used an approach to evaluate various pesticides like Hexaconazole, Mancozeb, Pretilachlor, Organophosphate and λ-cyhalothrin degradation capability of esterase. The enzyme was isolated from Salinicoccus roseus. Genome analysis unveiled the carboxylesterase genes underlying the degradation of pesticides, and was located between 2070Mbp to 2080Mbp region. Herein, partially purified esterase was immobilized into beads by mixing with an equal volume (1:1) of sodium alginate solution [2.5% (w/v)].Scanning electron microscopy (SEM) of the beads showed the microspheres for enhanced enzyme-substrate reaction, wide peak at 3316, 1635 and 696 cm in Fourier-transform infrared spectroscopy (FTIR) represented intermolecular hydrogen bonding, and thermogravimetric analysis (TGA) reaffirmed the binding of esterase entrapped into the beads. Maximum degradation rate (after 4 days) for free enzyme accounted 83.2% in Hexaconazole. Degradation rate moderately increased 4% in the presence of immobilized esterase. Degradation products were detected by liquid chromatography-mass spectrometry (LC-MS). Cytotoxicity test (root length and mitotic index) revealed differences in various treatments. Enzyme kinetics parameters, Michaëlis-Menten constant (K) 6.61 mM and maximum velocity (V) 1.89 µmol/min/mg increased after immobilization. Further, molecular docking results validated that esterase contributed to pesticide degradation by catalytic triad of Ser-His-Phe, ligand interactions, and specific binding pockets. Additionally, molecular dynamics (MD) simulations confirmed the protein-ligand conformational stability. Hence, present study highlighted an effective method for improving the catalytic properties of esterase, and also potential candidate for bioremediation of pesticides.
农业中化学农药的持续暴露及其在土壤和水中的污染对环境构成了严重威胁。当前的研究采用了一种方法来评估各种农药，如己唑醇、代森锰锌、丙草胺、有机磷和高效氯氟氰菊酯对酯酶的降解能力。该酶是从玫瑰盐球菌中分离出来的。基因组分析揭示了农药降解背后的羧酸酯酶基因，其位于2070Mbp至2080Mbp区域之间。在此，将部分纯化的酯酶与等体积（1:1）的海藻酸钠溶液[2.5%（w/v）]混合固定在珠子中。珠子的扫描电子显微镜（SEM）显示微球可增强酶-底物反应，傅里叶变换红外光谱（FTIR）中在3316、1635和696 cm处的宽峰代表分子间氢键，热重分析（TGA）再次证实了包埋在珠子中的酯酶的结合。游离酶的最大降解率（4天后）在己唑醇中为83.2%。在固定化酯酶存在下，降解率适度提高了4%。通过液相色谱-质谱联用（LC-MS）检测降解产物。细胞毒性试验（根长和有丝分裂指数）揭示了各种处理之间的差异。固定化后，酶动力学参数米氏常数（K）为6.61 mM，最大速度（V）为1.89 µmol/min/mg增加。此外，分子对接结果验证了酯酶通过Ser-His-Phe催化三联体、配体相互作用和特定结合口袋促进农药降解。此外，分子动力学（MD）模拟证实了蛋白质-配体构象稳定性。因此，本研究突出了一种改善酯酶催化性能的有效方法，也是农药生物修复的潜在候选方法。
