Closed-Loop Cellulose Saccharification via Branching-Modulated Oligomer Separation and Hydrolysis

Producing bioavailable glucose from abundant cellulose presents a sustainable pathway to address global food security challenges. This study demonstrates an integrated biorefinery strategy combining molten salt hydrate (LiBr MSH)-mediated hydrolysis with carbon affinity separation to overcome cellulose recalcitrance and glucose separation issues. Through in situ glycosylation engineering with glucose during cellulose hydrolysis in MSH, we synthesized branched glucan oligomers with a substitution degree of 7.9% that effectively decoupled dissolution-separation-conversion processes. The optimized MSH system achieved a 77.6% oligomer yield with 14.4% glucose conversion. The engineered branching conferred a remarkable 816.69 mg g^-1 adsorption capacity for oligomers on hydrophobic carbon CL-YP50F, demonstrating a 3.2-fold adsorption selectivity enhancement over direct glucose conversion. Thermodynamic analysis revealed spontaneous adsorption driven by an enhanced π-conjugation between aromatic carbon domains and oligomer hydrophobic motifs. Branched structural modification improved aqueous solubility by 48% relative to linear counterparts, enabling an 86.0% desorption efficiency. Subsequent mild acid hydrolysis (130 °C, 4 wt % H₂SO₄) achieved a near-quantitative glucose yield (98.4%) from the branched oligomers, attributed to their disrupted crystalline packing and reduced particle dimensions. This cascade process delivers a 7.3-fold glucose yield improvement versus conventional cellulose hydrolysis, establishing an efficient paradigm for lignocellulosic biomass valorization with minimized energy input and maximal carbon utilization.