Hydrolysis of biomass using a reusable solid carbon acid catalyst and fermentation of the catalytic hydrolysate to ethanol

• A glycerol based solid carbon acid catalyst found to hydrolyze biomass.
• Optimization of catalytic hydrolysis yields 31% efficiency with pretreated biomass.
• Catalyst can hydrolyze raw biomass with 20% efficiency.
• Negligible generation of fermentation inhibitors.
• Demonstrated catalyst reusability and fermentation using the catalytic hydrolysate.

Solid acid catalysts can hydrolyze cellulose with lower reaction times and are easy to recover and reuse. A glycerol based carbon acid catalyst developed at CSIR-IICT performed well in acid catalysis reactions and hence this study was undertaken to evaluate the catalyst for hydrolysis of biomass (alkali pretreated or native rice straw). The catalyst could release 262 mg/g total reducing sugars (TRS) in 4 h at 140 °C from alkali pretreated rice straw, and more importantly it released 147 mg/g TRS from native biomass. Reusability of the catalyst was also demonstrated. Catalytic hydrolysate was used as sugar source for fermentation to produce ethanol. Results indicate the solid acid catalyst as an interesting option for biomass hydrolysis.