Lignocellulose Pretreatment Combining Continuous Alkaline Single-Screw Extrusion and Ultrasonication to Enhance Biosugar Production

Abstract

Pretreatment to improve the enzymatic digestibility of highly crystallized lignocellulosic biomass is essential in biorefinery processes. This study investigates the combination of lignocellulose pretreatment with continuous alkaline single-screw extrusion and ultrasonication for biosugar production. Miscanthus sacchariflorus was used because it is a promising bioenergy crop. The results show that ultrasonication with continuous alkaline pretreatment increased the enzymatic digestibility of carbohydrates and reduced the use of chemicals during pretreatment. An hour of ultrasonication following 0.2 M NaOH (2.25 mol-NaOH/kg-biomass) continuous alkaline pretreatment resulted in a 6.7% increase in total biosugar production (83.1% of theoretical yield), a decrease of up to 26.1% in chemical usage, and a 17.0% increase in lignin removal compared with the case without ultrasonication. The developed method can be considered an effective and eco-friendly approach to the production of bio-based materials.

Keywords

• ultrasonication
• alkaline pretreatment
• continuous single-screw extrusion
• <i>Miscanthus sacchariflorus</i>
• biosugar