Unraveling latent affinity of strategically designed histidine-rich biosurfactant via tannery waste bio-upcycling in environmentally-relevant lignin removal from pulp and paper industry effluent

• Published in: Biocatalysis and agricultural biotechnology Vol. 62; p. 103426
• Main Authors: Uddin, Maseed, Ramachandran, Krithikaa, Venkatesan, Swathi Krishnan, Sekar, Karthikeyan, Ganesan, Sekaran, Kandasamy, Ramani
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2024
• Subjects: agricultural biotechnology; Animal fleshing; animals; biocatalysis; Bioremediation; biosurfactants; carbon; Cationic lipoprotein biosurfactant; electrostatic interactions; entropy; Gibbs free energy; histidine; kinetics; lignin; Lignin sequestration; lipoproteins; nitrogen; pulp and paper industry; Pulp and paper industry effluent; pulp and paper mill effluents; regression analysis; solid wastes; sorption isotherms; Tannery solid waste; tannery waste; temperature; Tannery solid waste; Pulp and paper industry effluent; Bioremediation; Lignin sequestration; Cationic lipoprotein biosurfactant; Animal fleshing
• ISSN: 1878-8181; 1878-8181
• DOI: 10.1016/j.bcab.2024.103426

Bioremediation of pulp and paper industry (PPI) effluent is hindered due to biorefractory lignin. Herein, we demonstrate a lignin-specific designer biosurfactant with synergistic binding sites for enhanced lignin removal from PPI effluent. The histidine rich-cationic lipoprotein biosurfactant (HR-CLB) was synthesized by Bacillus tropicus using tanning industry solid waste, animal fleshing by de novo substrate-dependent synthesis pathway. Interestingly, the HR-CLB anchored functionalized carbon (HR-CLBAFC) demonstrated a high lignin sequestration capacity of 93.2 mg/g HR-CLBAFC at optimized time, 60 min; pH, 5; temperature, 45 °C; and mass of HR-CLBAFC, 1.0 g. The sequestration was confirmed by HR-SEM, UV–Vis., FT-IR, and WCA analyses. The isotherm studies revealed the involvement of Freundlich isotherm (regression coefficient, R2: 0.988) in regulating lignin sequestration onto HR-CLBAFC with a Freundlich constant (Kf) of 16.46 ((mg/g)(L/mg)1/n). Moreover, the kinetics studies divulged the contribution of the pseudo-second-order kinetic model (R2: 0.992) in regulating the dynamic mechanism of lignin sequestration onto HR-CLBAFC with a rate constant (k2) of 0.00022 g/mg min. Additionally, the thermodynamics studies discovered a positive Gibbs free energy (ΔG: +170 kJ/mol) and entropy (ΔS°: +130 kJ/mol), indicating the involvement of chemical interaction during the sequestration. Furthermore, the mechanistic study confirmed the role of an incomplete valence shell of nitrogen in histidine centers of HR-CLB in regulating electrostatic interaction with lignin molecules during the sequestration process. Subsequently, the HR-CLBAFC applied for lignin sequestration from the real-time PPI effluent demonstrated an outstanding sequestration efficiency (>99.4%), confirming the unequivocal potential of the HR-CLBAFC matrix in lignin sequestration from real-time PPI effluent. State of the understanding of tannery solid waste with high histidine amino acid in regulating selectivity of bioupcylced histidine rich-cationic lipoprotein biosurfactant towards environmentally-relevant lignin in pulp and paper industry effluent. [Display omitted] •Biosequestration of environmentally-relevant biorefractory lignin in pulp and paper mill effluent (PPMI).•Application of designer histidine-rich cationic lipoprotein biosurfactant (HR-CLB) in lignin sequestration.•Mechanistic study unveiled the contribution of histidine residues of HR-CLB in regulating lignin sequestration via electrostatic interaction.•HR-CLB demonstrated exceptional high lignin sequestration efficiency from real-time PPMI.•The potential lignin sequestration mechanism of HR-CLB matrix was proposed.