A new coupled process was developed by combining several technologies including biomass pretreatment, direct biomass-to-electricity conversion and electrochemical reduction of the CO 2 produced during microbial fermentation of the enzymatic hydrolysate of pretreated substrates. This process was achieved by the assistance of several electron carriers for mediating the transfer of biomass endogenous electrons. Pretreatment of corn stover to increase cellulose accessibility for bioethanol production with the electron carriers being reduced works as a “charging” or “electron extraction” step. Re-oxidization of the reduced electron carriers in a liquid flow fuel cell works as an “electricity generation” step. Electrochemical reduction of CO 2 to form formic acid with co-production of hydrogen gas works as an “electricity consumption” step. Under the respective optimal condition of each step, this coupled process would obtain 155.6 g bioethanol, 145.3 g formic acid and 23.3 g hydrogen gas from 1000 g corn stover, achieving 47.0% increase in carbon efficiency and 88% increase in system energy efficiency. This coupled process could well increase the carbon efficiency of lignocellulose polysaccharide conversion, which thus may provide new technical routes for lignocellulose conversion with more carbon negativity.
Yuting Zhu,Yuhe Liao,Luying Lu,Wei Lv,Jing Liu,Xiangbo Song,Jingcheng Wu,Lei Li,Chenguang Wang,Longlong Ma,Bert F. Sels
Facile oxidation is a promising technology to valorize lignocellulosic biomass toward high-value chemicals and cellulose. However, the carbon efficiency is restricted by inevitable dissolution and conversion of carbohydrates and the condensation and degradation of lignin and monophenolics. Herein, we report the use of CuO nanoparticles (NPs) to oxidatively fractionate lignocellulose with O2 in aqueous NaOH under mild conditions, achieving over 80% carbon efficiency. Lignin was converted to aromatic aldehyde monomers (up to 48.6 wt %, mainly vanillin and syringaldehyde), and the yield can surpass the theoretical value (on the basis of the β-O-4 bond content) due to cleavage of other bonds. This was proven by several model compounds with different interlinkages. All hemicelluloses were transformed toward water-soluble small acids (mainly oxalic acid). As it was protected by the complexation of Cu cations, up to 80% cellulose was obtained as a white crystalline residue with high purity (>95%), which has potential applications in the production of materials and chemicals.
危险品化学品经营许可证（带存储）