Efficient and comprehensive utilization of sugarcane bagasse components through vanillic acid pretreatment

Abstract

Lignocellulosic biomass, being a renewable carbon-based resource, holds paramount practical significance in terms of its comprehensive conversion and utilization for effectively substituting petroleum-based energy sources. Herein, we present a sustainable and environmental-friendly vanillic acid (VA) pretreatment approach for efficient and comprehensive utilization of sugarcane bagasse (SCB). The xylo-oligosaccharides (XOS)DP2-6 yield of 60.4 % (wt.% of xylan) was achieved under the conditions of 180 °C/15 min/6% VA (wt.% of SCB), while lignin condensation was simultaneously inhibited in this initial biorefinery stage. Subsequently, the enzymatic saccharification of the pretreatment residue was significantly enhanced due to the reduced cellulase adsorption of lignin. Lignin structural characterization demonstrated that VA could effectively incorporate to the lignin structure, resulting in the lignin exhibiting high preservation of β-O-4′ linkages (39.38/100 Ar), low molecular weight (2410 Da), abundant phenolic hydroxyl groups (3.70 mmol/g), and less degree of condensation (0.33). Importantly, the resulting less-condensed lignin (LCL) could effectively undergo melt-blending with poly(butylene adipate-co-terephthalate) (PBAT) owing to its low glass transition temperature, thereby facilitating the establishment of enhanced intermolecular interactions (π–π interaction and hydrogen bond) between LCL and PBAT. These interactions enhanced the plasticization of PBAT on LCL, and as a result, the prepared P/LCL30 composite film possessed excellent tensile properties without requiring lignin modification or additional additives. The study presents a straightforward and efficient biorefinery conversion strategy for lignocellulosic biomass, wherein hemicellulose was degraded into XOS, cellulose was enzymatically hydrolyzed to glucose, and the remaining lignin with lower condensation was utilized as a filler of PBAT composite film.