Xie Xinyi, Li Canxin, Fan Di, Zhong Jian, Liu Qiyu, Qiu Xueqing, Ouyang Xinping
School of Chemistry & Chemical Engineering, South China University of Technology, Guangzhou510640, P. R. China.
School of Chemical Engineering & Light Industry, Guangdong University of Technology, Guangzhou510006, P. R. China.
J Agric Food Chem. 2022 Dec 14;70(49):15430-15438. doi: 10.1021/acs.jafc.2c06736. Epub 2022 Dec 2.
Traditional pretreatment of lignocellulose is usually conducted under higher acidic and high temperature conditions, which leads to both the degradation of sugar and the condensation of lignin, hindering the subsequent conversion. An effective approach to fractionate lignocellulose into 93.9% of noncondensed lignin, 99.4% of cellulose, 17.8% of xylose, and 66.7% of xylooligosaccharides under mild conditions was developed using the formic acid solution at 80 °C for 100 min. The β-O-4 bond content of lignin fractionated with formic acid (54.6 per 100 C9 units) was higher than dioxasolv lignin (48.4 per 100 C9 units), indicating that formic acid pretreatment well protected the ether bonds in lignin. Therefore, the hydrogenolysis of fractionated lignin contributed to 28.0% of aromatic monomer yield, which was comparable to dioxasolv lignin. As cellulose possesses a large amount of porosity because lignin was separated from lignocellulose, the hydrolysis of fractionated cellulose by molten salt hydrates gave a 96.4% of glucose yield.
木质纤维素的传统预处理通常在高酸性和高温条件下进行，这会导致糖的降解和木质素的缩合，从而阻碍后续的转化。采用80℃的甲酸溶液处理100分钟，开发出了一种在温和条件下将木质纤维素分离成93.9%的非缩合木质素、99.4%的纤维素、17.8%的木糖和66.7%的低聚木糖的有效方法。用甲酸分离得到的木质素的β-O-4键含量（每100个C9单元中有54.6个）高于二氧六环木质素（每100个C9单元中有48.4个），这表明甲酸预处理很好地保护了木质素中的醚键。因此，分离得到的木质素的氢解反应使芳香族单体产率达到了28.0%，这与二氧六环木质素相当。由于木质素从木质纤维素中分离出来后，纤维素具有大量的孔隙，因此用熔融盐水合物对分离得到的纤维素进行水解，葡萄糖产率达到了96.4%。
