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Herein, we investigated the synergistic effects of jet milling (JM) and deep eutectic solvent (DES) pretreatment on the fractionation of grapevine lignin and the consequent enhancement of enzymatic hydrolysis. Grapevine, a substantial byproduct of the wine industry, was subjected to JM pretreatment to produce finely powdered particles (median diameter D 50 = 98.90), which were then further treated with acidic ChCl-LA and alkaline K 2 CO 3 -EG DESs. The results revealed that the combined JM + ChCl-LA pretreatment significantly increased the cellulose preservation under optimal conditions (110 °C, 4 h, and 20 % water content), achieving removal rates of 74.18 % xylan and 66.05 % lignin, respectively. The pretreatment temperature and inhibitor production were reduced, resulting in a remarkable threefold increase in glucose yield compared to untreated samples. Moreover, the structural analysis of the pretreated lignin indicated an enrichment of phenolic units, leading to enhanced antioxidant and antibacterial activities, particularly in the JM pretreated samples. These findings underscore the promising potential of the synergistic JM and DES pretreatment in facilitating the efficient utilization of grapevine lignocellulosic biomass for sustainable biorefinery technologies. [Display omitted] • Jet milling effectively reduces the size of grapevines, facilitating fractionation. • Synergistic pretreatment with JM and DES greatly improves enzymatic glucose yield. • JM + ChCl-LA lignin retains syringyl and guaiacyl with high phenolic hydroxyl content. • JM + ChCl-LA lignin exhibits excellent biological activity properties. [ABSTRACT FROM AUTHOR]

Herein, three pretreated grapevine lignins were incorporated into carboxymethyl cellulose films. The effects of traditional NaOH pretreated lignin and DES (ChCl-LA, ChCl-LA & K 2 CO 3 -EG) pretreated lignin on film properties were compared. Modern analytical techniques were employed to systematically characterize the pretreated lignin and the different CMC-lignin films. The results showed that DES lignin was of high purity, low molecular weight, and homogeneous structure. It outperformed traditional NaOH lignin in terms of compatibility with CMC, enabling it to perform its bioactivity and physicochemical functions in films. This feature effectively enhanced the hydrophobicity, UV shielding ability, water vapor barrier, thermal stability, mechanical properties, and biological activity of CMC-DES lignin film. NMR (2D HSQC) showed that the excellent antioxidant and antibacterial capabilities of CMC-DES lignin film are due to the retention of butyl (S) and p -hydroxyphenyl (H) units in DES lignin, resulting in its rich phenolic hydroxyl content. The detailed structural elucidation of DES lignin's chemical interactions with CMC provided valuable insights into the advantageous properties observed in the films, presenting innovative solutions for applications in the food packaging and preservation industries. • DES two-step pretreated grapevine lignin successfully combined with CMC films. • The effects of NaOH lignin and DES lignin on CMC-based film were investigated. • DES lignin enhances biological activity and physicochemical function of CMC film. • DES lignin retains more phenolic hydroxyl for better antimicrobial and antioxidant. [ABSTRACT FROM AUTHOR]

Herein, DES lignin was obtained by pretreatment of grapevine with a deep eutectic solvent (ChCl-LA). A novel chitosan-DES lignin composite aerogel material (CS-LIG aerogel) was prepared to adsorb methylene blue (MB), Congo red (CR), catechin (C), and epicatechin (EC). The CS-LIG aerogel was systematically characterized by modern technological instruments. It was demonstrated that the DES lignin was successfully incorporated and had an important effect on the morphological structure and adsorption of dyes and natural products in the aerogel. The adsorption kinetic models for both adsorbed CR and MB are pseudo-second-order models. Adsorption isotherms followed Langmuir for the adsorption of CR and Freundlich for the adsorption of MB. The π-π interaction and hydrogen bonding of DES lignin aromatic groups in CS-LIG aerogels were responsible for the adsorption of C and EC with 86.42 % and 90.85 % removal rates, respectively. This study opens a new avenue for the high-value utilization of DES lignin and the preparation of chitosan-based composites for the adsorption of dyes and purification of natural products. • DES lignin incorporation enhances the thermal stability of CS aerogel. • Adsorption of dyes on CS-LIG aerogels is mainly electrostatic and hydrogen bonding. • The CS-LIG aerogel can selectively adsorb C and EC from proanthocyanidins. • Lignin π-π interactions of aromatic groups are primarily reason for adsorb C and EC. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs) have been extensively applied to pretreat lignocellulose; however, comparative research on acidic and alkaline DES pretreatment is relatively lacking. Herein, pretreatment of grapevine agricultural by-products with seven DESs were compared in terms of removal of lignin and hemicellulose and component analysis of the pretreated residues. Among the tested DESs, both acidic choline chloride-lactic (CHCl-LA), and alkaline potassium carbonate-ethylene glycol (K 2 CO 3 -EG) were effective in delignification. Thereafter, the CHCl-LA and K 2 CO 3 -EG extracted lignin was compared by analyzing their physicochemical structure changes and antioxidant properties. The results showed that the thermal stability, molecular weight, and phenol hydroxyl percentage of CHCl-LA lignin were inferior to K 2 CO 3 -EG lignin. It was found that the high antioxidant activity of K 2 CO 3 -EG lignin was mainly attributed to the abundant phenol hydroxyl, guaiacyl (G), and para-hydroxy-phenyl (H). By comparing acidic and alkaline DES pretreatments and their lignin nuances in biorefining, novel insights are derived for the scheduling and selection of DES for lignocellulosic pretreatment. • CHCl-LA pretreatment has a great advantage in removing lignin and hemicellulose. • K 2 CO 3 -EG pretreatment benefits lignin structure and thermal stability preservation. • Significant chemical shift in the guaiacyl lignin unit of K 2 CO 3 -EG lignin. • K 2 CO 3 -EG lignin retains more phenol hydroxyl have better antioxidant properties. [ABSTRACT FROM AUTHOR]