Recyclable deep eutectic solvent coupling sodium hydroxide post-treatment for boosting woody/herbaceous biomass...

Area of Science:

• Biomass Conversion
• Green Chemistry
• Biorefinery Processes

Background:

• Biomass recalcitrance hinders efficient conversion to biofuels and chemicals.
• Developing cost-effective and sustainable pretreatment methods is crucial for biorefineries.

Purpose of the Study:

• To develop and evaluate a novel recyclable deep eutectic solvent (DES) for biomass pretreatment.
• To enhance enzymatic hydrolysis efficiency of pretreated woody and herbaceous biomass.
• To investigate the correlation between lignin/xylan removal and cellulose conversion.

Main Methods:

• A recyclable DES composed of p-toluene sulfonic acid (p-TsOH) and choline chloride (ChCl) was synthesized.
• Woody poplar sawdust (PL) and herbaceous miscanthus (MC) were pretreated using the DES system.
• NaOH post-treatment was applied to DES-pretreated residues to remove residual lignin.
• Enzymatic hydrolysis was performed to determine cellulose conversion efficiency.

Main Results:

• Near complete cellulose conversion (>90%) was achieved for both PL and MC residues within 40 minutes at 100°C.
• The DES pretreatment coupled with NaOH post-treatment resulted in high delignification and xylan removal (>90%).
• Strong positive correlations were observed between xylan/lignin removal and cellulose conversion efficiency for both biomass types.

Conclusions:

• The developed DES system combined with NaOH post-treatment offers an efficient and economically feasible approach for biomass conversion.
• This method is effective for both woody and herbaceous biomass residues, paving the way for sustainable biorefining.
• The findings highlight the potential of DES as a green solvent for biomass pretreatment.