Valorization of Lignocellulosic Biomass toward Multipurpose Fractionation: Furfural, Phenolic Compounds, and Ethanol

Abstract

Lignocellulose is typically considered as one of the most promising feedstocks to produce a variety of renewable fuels and value-added chemicals. In this study, we developed an alternative valorization of lignocellulosic biomass toward multipurpose fractionation. Since the adopted pretreatment with a fully recyclable acid, p-TsOH, can significantly facilitate the degradation of hemicellulose, we initially converted hydrolysate into furfural with an average yield of 63.38% under the selected pretreatment condition. Next, a biomass-derived solvent, γ-valerolactone (GVL), was used to extract lignin from pretreated substrate, and a suggested pretreatment temperature 100 °C was proposed according to the characterization results from FTIR, 31P NMR, TGA, GPC, and 2D HSQC NMR. The obtained lignin, which exhibited excellent properties such as low molecular weight (Mw, 16053 g/mol), narrow polydispersities (Mw/Mn, 2.48), and high content of aliphatic OH (3.72 mmol/g), was easily upgraded to phenolic compounds by hydrogenation with a yield of 76.41%. Finally, the leftover cellulose-rich solid was directly degraded to glucose after enzymatic saccharification (92.57% theoretical yield). Following fermentation of glucose led to a high yield of ethanol production (41.08 g/L). Therefore, the described synergy exhibited a practical significance for the comprehensive use of the lignocellulose resource.