Zeng Shiyi, Ma Qingzhi, Zhang Shenchong, Shen Conghao, Li Jing, Zhao Huifang, Guo Daliang, Zhang Yan, Yang Hui
School of Environmental and Nature Resources, Zhejiang University of Science & Technology, Hangzhou, Zhejiang Province, China.
School of Environmental and Nature Resources, Zhejiang University of Science & Technology, Hangzhou, Zhejiang Province, China.
Int J Biol Macromol. 2023 Feb 28;229:861-872. doi: 10.1016/j.ijbiomac.2022.12.301. Epub 2022 Dec 29.
To develop a characteristic "Lignin-first" strategy, the oxy-organosolv delignification processes under mild conditions were comprehensively investigated. Results showed that lignin yield could achieve about 50 % under the optimum process conditions of ethanol concentration 80 %, temperature 90 °C, liquid to wheat straw ratio 25:1 for powdery-scale substrates, which was 65.0 % higher than that for rod-scale substrates under the same conditions. The lignin structural and carbohydrate component results demonstrated the employment of oxygen induced great quantities of lignin dissolving out on the premise of little carbohydrate component (<1 %) and lignin structural (mainly β-O-4 units) changes. Moreover, based on the molecular weight and polydiversity comparison results, the aqueous oxygen could transfer homogeneously in mild organosolv system and result in lignin degradation uniformly. Besides, the employment of oxygen assisted in not only extending the massive lignin removal stage to 30 min and 50 min for P-OEEL and R-OEEL respectively, but also boost the delignification rate with comparison to P-EL and R-EL. Lastly, the excellent anti-oxidant properties of lignin from oxy-organosolv process were demonstrated by scavenging DPPH and ABTS radicals. The economic calculations showed that the cost for lignin production were about 1.58USD/g lignin from powdery-scale wheat straw, providing a competitive route for high-value utilize waste biomass.
为了开发一种具有特色的“木质素优先”策略，对温和条件下的氧有机溶剂脱木质素过程进行了全面研究。结果表明，在乙醇浓度80%、温度90℃、粉状底物液固比25:1的最佳工艺条件下，木质素产率可达50%左右，比相同条件下棒状底物的木质素产率高65.0%。木质素结构和碳水化合物成分结果表明，在碳水化合物成分变化较小（<1%）和木质素结构（主要是β-O-4单元）变化较小的前提下，氧气的使用促使大量木质素溶解出来。此外，基于分子量和多分散性比较结果，水相氧能够在温和的有机溶剂体系中均匀转移，从而使木质素均匀降解。此外，氧气的使用不仅使P-OEEL和R-OEEL的大量木质素去除阶段分别延长至30分钟和50分钟，而且与P-EL和R-EL相比提高了脱木质素率。最后，通过清除DPPH和ABTS自由基证明了氧有机溶剂法木质素具有优异的抗氧化性能。经济计算表明，粉状小麦秸秆生产木质素的成本约为1.58美元/克木质素，为高价值利用废弃生物质提供了一条具有竞争力的途径。
