Sustainable\nPathway for Bagasse Conversion Using Continuous\nLactic Acid Catalysis: Production of Xylo-Oligosaccharides, Lignin\nNanoparticles, and Dissolving Pulp

Organic\nacid pretreatment has the potential for cleaner\nproduction\nand efficient energy use. This work demonstrated the selective separation\nof hemicellulose and lignin from bagasse using lactic acid (LA), and\nimproved the processability of cellulose. Initially, 0.1% LA hydrolysis\nof bagasse converted the xylan to xylo-oligosaccharides with a yield\nof 65.0%. Subsequently, lignin was isolated from the residue of bagasse\nby an 80% LA pretreatment, achieving an efficiency of 91.2%. Importantly,\nthe solid residue retained a high glucan content of 88.2%. Following\nsodium hydroxide incubation, cellulase hydrolysis of solid residue\nachieved a saccharification efficiency of 92.5%, which was primarily\ndue to the solubilization of pseudolignin and the de-esterification\nof cellulose. Additionally, the cellulose residue proved to be suitable\nfor preparation of high-quality dissolving pulp with high purity and\nhigh Fock reactivity. The lignin recovered from the 80% LA pretreatment\nsolution exhibited high purity (95.7%) and contained high carboxyl\nand hydroxyl contents, enabling it to self-assemble into uniformly\nsized lignin nanoparticles. Furthermore, even after five cycles of\nLA solution reuse, it maintained an excellent lignin dissolution capacity.\nEconomic assessments also indicated that this process could generate\nsubstantial commercial benefits. The proposed LA gradient pretreatment\nprovided a sustainable strategy for comprehensive value addition of\nbiomass.