Mitigating Cellulose Interchain Forces to Produce Water-Soluble Glucan Oligomers via Forming Branched Glucan Chains in Molten Salt Hydrates

Glucan oligomers represent a high-value biochemical with distinctive applications in plant elicitors, probiotics, and anti-inflammatory pharmaceuticals. Selective conversion of sustainable cellulose to glucan oligomers significantly improves the economic viability of lignocellulosic biorefining. However, abundant hydroxyl groups on cellulose chains create strong interchain cohesion via hydrogen-bonding networks, severely hindering efficient cellulose processing in aqueous systems. This study presents an innovative cellulose exfoliation and hydrolysis strategy using glucose branching in a nonacidified molten salt hydrate (MSH). By strategically introducing glucose units at cellulose branching points, we address three critical challenges: (1) creating steric hindrance to disrupt interchain cohesion, (2) reducing hydrogen bonding between linear cellulose chains, and (3) enabling controlled glycosidic bond cleavage for oligomer production. Atomic force microscopy (AFM) direct force measurements quantitatively demonstrated reduced interchain adhesion from −0.285 to −0.058 mN/m following glucose branching. The optimized system achieved 80.6% yield of water-soluble glucan oligomers at 130 °C within 3 h, representing a 2.3-fold enhancement over conventional hydrolysis methods. Postreaction, glucan oligomers were efficiently isolated from the MSH medium through activated carbon adsorption, enabling MSH recycling.