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A waste-minimized biorefinery scenario for the hierarchical conversion of agricultural straw into prebiotic xylooligosaccharides, fermentable sugars and lithium-sulfur batteries

Xu, Jikun, Liu, Bingchuan, Wu, Longsheng, Hu, Jingping, Hou, Huijie, Yang, Jiakuan
Industrial crops and products 2019 v.129 pp. 269-280
batteries, biofuels, biomass, biorefining, carbon, cathodes, cellulose, digestibility, energy, enzymatic hydrolysis, feedstocks, glucose, hot water treatment, lignin, moieties, molecular weight, prebiotics, protocols, sulfur, surface area, value added, wheat straw, xylan, xylooligosaccharides
How to exert the value-added superiority was a key link in the development of biomass valorization that heightens an appeal for a waste-minimized protocol. The fractional use of three building blocks in biomass became an urgent challenge to be faced. Herein, we report an autohydrolysis-aided biorefinery for the sequential conversion of wheat straw hemicelluloses, cellulose and lignin into xylooligosaccharides (XOS), fermentable glucose and lithium-sulfur cathode at the end of the process, respectively. The yield of XOS (DP of 2–6) reached up to 24.06% (w/w) of xylan and 6.19% (w/w) of the initial biomass. The hydrothermal treatment removed the amorphous portion and disrupted the rigid structure, thereby improving the cellulose digestibility from 14.1 to 88.9%. The molecular weights, functional groups and structural features of residual lignin after enzymatic hydrolysis were thoroughly explored for the cathode of lithium-sulfur batteries via the carbonizing process. Because of the considerable surface area, the covalent linkage between the lignin-derived carbon (LC) and sulfur, and the uniform dispersion of sulfur particles, the developed LC@S cathode exhibited excellent rate capability, and the specific capacity of 1238, 1085 and 1035 mA h g−1 at 0.1, 0.2 and 0.5 C, respectively. The LC@S cathode retained 596 mA h g−1 after 200 cycles at 0.5 C with a coulombic efficiency of 92%. The present study provides a systematic strategy that bears the primary responsibility for exploiting biomass into a potential feedstock with worthwhile functions in the thriving domains of chemicals, biofuels and energy storage devices.