Biomolecules and Biocatalysis Laboratory, Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur, 603203, Chengalpattu District, Tamil Nadu, India.
Environment & Sustainability Department, CSIR-Institute of Minerals and Materials Technology, Bhubaneswar, 751013, Odisha, India.
J Environ Manage. 2021 Dec 15;300:113755. doi: 10.1016/j.jenvman.2021.113755. Epub 2021 Sep 16.
Bioremediation of municipal landfill leachate (MLL) is often intricate due to presence of refractory lignin. In the present study, it was attempted to tailor the histidine rich protein moiety of cationic lipoprotein biosurfactant (CLB) to sequester the lignin from MLL. Animal fleshing (AF), the solid waste generated in tanning industry was utilized for the production of histidine rich CLB by de novo substrate dependent synthesis pathway involving Bacillus tropicus. The optimum conditions for the maximum production of CLB were determined using response surface methodology. At the optimized conditions, the maximum yield of CLB was 217.4 mg/g AF (on dry basis). The produced histidine rich CLB was purified using Immobilized metal affinity chromatography at the optimum binding and elution conditions. The histidine residues were more pronounced in the CLB, as determined by HPLC analysis. The CLB was further characterized by SDS-PAGE, Zeta potential, XRD, FT-IR, Raman, NMR, GC-MS and TG analyses. The CLB was immobilized onto functionalized nanoporous activated bio carbon (FNABC) and the optimum immobilization capacity was found to be 211.6 mg/g FNABC. The immobilization of CLB onto FNABC was confirmed using SEM, FT-IR, XRD and TG analyses. The isotherm models, kinetic and thermodynamics studies of CLB immobilization onto FNABC were performed to evaluate its field level application. Subsequently, the CLB-FNABC was then applied for the sequestration of lignin in MLL. The maximum lignin sequestration was achieved by 92.5 mg/g CLB-FNABC at the optimized sequestration time, 180 min; pH, 5; temperature, 45 °C and mass of CLB-FNABC, 1.0 g. The sequestration of lignin by CLB- FNABC was confirmed by SEM, FT-IR and UV-Vis analyses. Further, the mechanistic study revealed the anchoring of CLB onto the surface of lignin through electrostatic interaction.
生物修复城市垃圾渗滤液（MLL）通常很复杂，因为存在难处理的木质素。在本研究中，试图通过阳离子脂蛋白生物表面活性剂（CLB）中的组氨酸丰富蛋白部分来螯合 MLL 中的木质素。动物碎肉（AF）是制革工业产生的固体废物，用于通过涉及热带芽孢杆菌的从头合成途径生产富含组氨酸的 CLB。使用响应面法确定了最大生产 CLB 的最佳条件。在优化条件下，CLB 的最大产量为 217.4 mg/g AF（干基）。通过固定化金属亲和层析在最佳结合和洗脱条件下对产生的富含组氨酸的 CLB 进行纯化。通过 HPLC 分析确定，CLB 中的组氨酸残基更为明显。通过 SDS-PAGE、Zeta 电位、XRD、FT-IR、拉曼、NMR、GC-MS 和 TG 分析对 CLB 进行了进一步表征。将 CLB 固定在功能化纳米多孔生物活性炭（FNABC）上，发现最佳固定化容量为 211.6 mg/g FNABC。使用 SEM、FT-IR、XRD 和 TG 分析证实了 CLB 固定在 FNABC 上。对 CLB 固定在 FNABC 上的等温线模型、动力学和热力学研究进行了评价，以评估其现场应用水平。随后，将 CLB-FNABC 应用于 MLL 中木质素的螯合。在优化的螯合时间 180 min、pH 值 5、温度 45°C 和 CLB-FNABC 质量 1.0 g 的条件下，CLB-FNABC 可实现最大木质素螯合率 92.5 mg/g。通过 SEM、FT-IR 和 UV-Vis 分析证实了 CLB-FNABC 对木质素的螯合。此外，机制研究表明 CLB 通过静电相互作用锚定在木质素表面。
