One-step lignocellulose fractionation using acid/pentanol pretreatment for enhanced fermentable sugar and reactive lignin production with efficient pentanol retrievability

To valorize whole lignocellulosic biomass, this study proposed a biphasic solvent system using dilute acid (DA)/pentanol pretreatment. Effects of the key factors, i.e., temperature and pentanol concentration, on aspen were evaluated. Under identified optimal pretreatment conditions (160 degrees C, 60% pentanol), 85% and 91% of lignin and hemicellulose were solubilized in separate organic and liquid phases, respectively, while 91.1% of cellulose was retained in solid fraction. Enzymatic digestibility efficiency of pretreated cellulose was similar to 6.4-times higher than that of untreated biomass. Notably, excellent pentanol recovery rates were obtained after four-times recycling (84%) with great cellulose digestibility (81%) and delignification (71%) performance. The recovered lignin contained low levels of contaminated sugars (<1%), while it could stabilize and protect high amounts of beta-O-4 bonds. Besides, high phenolic OH content was found in lignin, which could be utilized for lignin-based biomaterials. Therefore, DA/pentanol pretreatment is an innovative promising technology for lignocellulosic valorization towards biorefinery.

Automated summary

This study proposed a biphasic solvent system using dilute acid/pentanol pretreatment for lignocellulosic biomass valorization. The results showed that lignin and hemicellulose were solubilized in separate organic and liquid phases, while cellulose was retained in the solid fraction under optimal pretreatment conditions. Enzymatic digestibility efficiency of pretreated cellulose was greatly improved. Additionally, the recovered lignin contained low levels of contaminated sugars and had high amounts of β-O-4 bonds and phenolic OH content, which could be utilized for lignin-based biomaterials.