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

Area of Science:

• Biomass Conversion
• Sustainable Chemistry
• Biorefinery Technology

Background:

• Cellulose recalcitrance and glucose separation are major hurdles in lignocellulosic biomass valorization.
• Sustainable glucose production is crucial for food security and reducing reliance on fossil fuels.

Purpose of the Study:

• To develop an integrated biorefinery strategy for efficient cellulose hydrolysis and glucose separation.
• To overcome cellulose recalcitrance using molten salt hydrate (MSH) and in situ glycosylation engineering.
• To enhance glucose yield and purity through a cascade process involving branched glucan oligomers.

Main Methods:

• Utilized molten salt hydrate (LiBr MSH)-mediated hydrolysis with in situ glycosylation engineering.
• Synthesized branched glucan oligomers via cellulose hydrolysis in MSH.
• Employed carbon affinity separation for oligomer adsorption and desorption.
• Performed mild acid hydrolysis of branched oligomers to yield glucose.

Main Results:

• Achieved 77.6% oligomer yield and 14.4% glucose conversion in the optimized MSH system.
• Engineered branched glucan oligomers exhibited a 3.2-fold enhanced adsorption selectivity (816.69 mg g⁻¹).
• Branched oligomers showed 48% improved aqueous solubility and 86.0% desorption efficiency.
• Near-quantitative glucose yield (98.4%) obtained from mild acid hydrolysis of branched oligomers.
• Demonstrated a 7.3-fold glucose yield improvement compared to conventional cellulose hydrolysis.

Conclusions:

• The integrated biorefinery strategy effectively overcomes cellulose recalcitrance and glucose separation challenges.
• In situ glycosylation engineering and carbon affinity separation provide an efficient pathway for biomass valorization.
• This approach offers a sustainable and energy-efficient method for producing bioavailable glucose from cellulose.