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The lignin-derived inhibition on cellulase is the most critical bottleneck that must be addressed when converting lignocellulosic biomass through the sugar-platform process. Herein, a novel modified cellulase with high activity, great stability and excellent lignin-resistant ability was synthesized by chemical modification using hydrophilic and negatively charged polyethylene glycol (PEG) derivatives including HO-PEG-COOH and HOOC-PEG-COOH. Both modifications obviously increased the cellulase activity, with 37% (HO-PEG-COOH modification) and 53% (HOOC-PEG-COOH modification) increase, respectively. In addition, the stabilities of both modified cellulases were significantly enhanced, seeing from their much higher activities at all selected temperatures and pH values. The modification resulted in a movement of tryptophan residues to the exterior of enzyme, allowing the substrate chains to be more easily recruited and thus initiating the hydrolysis. The compactness of secondary structure for enzyme was improved, especially, the α-helix content was increased which requires strong hydrogen bonding to generate it, thus enhancing the stability. High hydrophilicity, negative charge and compactness of enzyme conferred modified cellulase good ability to resist lignin adsorption and destruction, thus improving the enzymatic hydrolysis of corn stover. [Display omitted] • Cellulase activity is significantly improved by up to 52% after chemical modification. • The migration of Trp residues allows the hydrolysis to be more easily initiated. • High compactness gives modified cellulase great stability and low level of damage by lignin. • High hydrophilicity and negative charge of modified cellulase prevent lignin adsorption. • The novel modified cellulase exhibits promising potential in converting corn stover. [ABSTRACT FROM AUTHOR]

Global liquid packaging industry has been greatly spurred by the rapidly growing food & beverage industry all over the world. Liquid packaging board (LPB), as the main composition (75–80 %) of laminated liquid packaging cartons, must possess high-quality of hydrophobicity and physical properties for excellent leak-proof and protecting the packaged commodity. Herein, in this study, lignin is selected to prepare lignin cationic surfactant (LCS) by quaternary ammonium modification. Then cationic lignin modified rosin size (L -CDRS) with uniform microsphere structure and high colloidal stability is successfully synthesized via a phase inversion process to improve the sizing performance and mechanical properties of LPB. The cation modified LCS presents improved amphipathicity of rich cationic charges and hydrophobic benzene ring skeleton, thus enhancing the electrostatic interactions between LCS and pulp fibers and improving the sizing performance of L -CDRS. The sizing performance of LPB is evaluated by varying the LCS dosages within L -CDRS and concluded that the edge penetration value and Cobb value of LPB handsheets exhibit an improved size performance with 2 % LCS within L -CDRS, implying the formation of homogeneous hydrophobic surface layer induced by the well-distribution of L -CDRS. In addition, the tensile index of LPB increased from 19.74 N·m/g to 25.96 N·m/g assisted by 2 % LCS emulsified L -CDRS, indicating an improved mechanical property. This study puts forward a practical and facile strategy to improve the sizing performance and mechanical properties facilitated by lignin enhanced rosin size and will further broaden the application range of traditional rosin size and lignin in LPB products. [Display omitted] • Lignin was modified into quaternary ammonium etherified cationic surfactant with improved emulsifying ability. • Cationic lignin can emulsify rosin to prepare L -CDRS with uniform microsphere structure and high colloidal stability. • L -CDRS exhibited a significantly improved sizing performance of LPB compared with the control rosin size. • The addition of L -CDRS contributed greatly to the enhanced mechanical properties of LPB. • The mechanism of improved sizing performance and mechanical properties of LPB induced by L -CDRS size agent was proposed. [ABSTRACT FROM AUTHOR]

The preparation of carbon quantum dots (CQDs) with excellent photoluminescence (PL) properties from biomass is a hot research topic. Herein, nitrogen-doped CQDs (N-CQDs) from lignin (C-source) using diethylenetriamine (DETA) as an N-source were synthesized via a facile, green, and large-scale solvothermal approach. The as-synthesized N-CQDs in ethanol (N-CQDs-ET) exhibit unique structures with abundant N-doping (~7.2%), rich functional groups (especially C O and pyrrolic-N), high degree of graphitization, and uniform particle size (~5.0 nm). The N-CQDs-ET have excellent QL properties with high quantum yield, superior fluorescence stability, and long fluorescence lifetime, all of which are much better than N-CQDs obtained from a traditional hydrothermal process. The N-CQDs-ET display excellent sensitivity for Fe3+ and Co2+ detection with a good linear correlation ranging from 0.27 to 250 μM and 0.45–500 μM, respectively. In addition, the N-CQDs-ET exhibit excellent biocompatibility and multicolored cell imaging ability, showing great potential applications in biosensors. [Display omitted] • Lignin derived N-CQDs are efficiently produced via ethanol solvothermal approach. • N-CQDs produced in ethanol have excellent QL properties due to unique structures. • N-CQDs produced in ethanol have better QL properties than those in hot water. • The N-CQDs-ET sample displays excellent sensitivity for Fe3+ and Co2+ detection. • N-CQDs-ET sample has great biocompatibility and cell multicolored imaging ability. [ABSTRACT FROM AUTHOR]