Acid-catalyzed glycerol organosolv (GO) pretreatment is a promising method for lignocellulosic biomass (LCB) fractionation. However, this method often leads to lignin repolymerization, intensifying lignin's inhibitory effects on subsequent enzymatic hydrolysis and limiting the production of highly active lignin, thereby hindering its valorization. This study explored incorporating polyethylene glycol (PEG) into acidic-catalyzed GO to improve bioethanol and bio-oil yields, with a focus on improving the yield of light aromatics, from LCB. Optimized PEG-aided GO pretreatment achieved a significantly higher bioethanol yield (23.7 g/L) compared to GO (17 g/L) and dilute acid (DA: 11.3 g/L) pretreatments. This improvement is attributed to the ability of PEG to mitigate lignin inhibition and modify the physicochemical properties of the pretreated substrate. Furthermore, thermal pyrolysis of PEG-aided GO lignin, obtained after the fermentation process, resulted in a substantially increased bio-oil yield (45.5 %) compared to GO (19 %) and DA (12 %). The enhanced bio-oil yield from PEG-aided GO lignin is ascribed to the promotion of β-O-4 linkages and the formation of β-O-4′ linkages. Characterization of the pyrolysis bio-oil revealed that light aromatic compounds were the dominant fraction, with their relative abundance significantly increasing from DA (5.9 %) to GO (9.7 %) and PEG-aided GO lignin (24.9 %). The PEG-aided GO method achieved an energy output of 8.85 MJ/kg, exceeding that of the GO and DA methods by 31 % and 57 %, respectively. The energy conversion efficiency of the PEG-aided GO method was 70 %, demonstrating a significant improvement compared to GO (57 %) and DA (51 %). This approach promotes the circular economy by upcycling LCB for bioethanol and valuable light aromatic compound production.

中文翻译：

---

通过聚乙二醇辅助酸性甘油预处理从木质纤维素联产生物乙醇和轻芳烃的综合方法


酸催化甘油有机溶剂（GO）预处理是木质纤维素生物质（LCB）分级分离的一种有前景的方法。然而，这种方法往往会导致木质素再聚合，加剧木质素对后续酶解的抑制作用，限制高活性木质素的产生，从而阻碍其增值。本研究探索将聚乙二醇 (PEG) 掺入酸催化的 GO 中，以提高生物乙醇和生物油的产量，重点是提高 LCB 中轻质芳烃的产量。与 GO (17 g/L) 和稀酸 (DA: 11.3 g/L) 预处理相比，优化的 PEG 辅助 GO 预处理实现了显着更高的生物乙醇产量 (23.7 g/L)。这种改进归因于 PEG 能够减轻木质素抑制并改变预处理基材的物理化学性质。此外，与 GO (19%) 和 DA (12%) 相比，发酵过程后获得的 PEG 辅助的 GO 木质素的热解导致生物油产量大幅增加 (45.5%)。 PEG辅助的GO木质素生物油产量的提高归因于β-O-4键的促进和β-O-4'键的形成。热解生物油的表征表明，轻质芳香族化合物是主要成分，其相对丰度从 DA (5.9%) 显着增加到 GO (9.7%) 和 PEG 辅助的 GO 木质素 (24.9%)。 PEG辅助的GO方法实现了8.85 MJ/kg的能量输出，分别超过GO和DA方法31%和57%。 PEG辅助的GO方法的能量转换效率为70％，与GO（57％）和DA（51％）相比有显着提高。 这种方法通过升级回收 LCB 来生产生物乙醇和有价值的轻质芳香化合物，从而促进循环经济。