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A two-stage pretreatment process is proposed in this research in order to improve sugar recovery from corn stover. In the proposed process, corn stover is hydrolyzed by dilute hydrochloric acid to recover xylose, which is followed by a Fenton reagent oxidation to remove lignin. 0.7 wt% dilute hydrochloric acid is applied in the first stage pretreatment at 120 °C for 40 min, resulting in 81.0% xylose removal. Fenton reagent oxidation (1 g/L FeSO 4 ·7H 2 O and 30 g/L H 2 O 2 ) is performed at room temperature (about 20 °C) for 12 has a second stage which resulted in 32.9% lignin removal. The glucose yield in the subsequent enzymatic hydrolysis was 71.3% with a very low cellulase dosage (3 FPU/g). This two-stage pretreatment is effective due to the hydrolysis of hemicelluloses in the first stage and the removal of lignin in the second stage, resulting in a very high sugar recovery with a low enzyme loading. [ABSTRACT FROM AUTHOR]

A two-stage process was evaluated to increase sugar recovery. Firstly, corn stover was treated with dilute hydrochloric acid to recover the xylose, and then the residue was subjected to a wet-milling pretreatment. Dilute hydrochloric acid showed a high xylose recovery during the first stage. The optimal condition was 120 °C and 40 min for 0.7 wt% dilute hydrochloric acid pretreatment followed by wet-milling pretreatment for 15 min. The xylose and glucose yield were 81.0% and 64.0%, respectively, with a cellulase dosage at 3 FPU/g of substrate. This two-stage process was effective on account of the removal of hemicelluloses in the first stage and the delamination of cell wall in the second stage, increasing the possibility of adsorption of cellulose to enzymes, and resulting in a high sugar recovery with a very low enzyme loading. [ABSTRACT FROM AUTHOR]

In this study, a novel catalyst, S 2 O 8 2− -KNO 3 /TiO 2 , which has active acidic and basic sites, was prepared and used in lignin hydrocracking with a co-catalyst, Ru/C. Ru/C is an efficient hydrogenation catalyst and S 2 O 8 2− -KNO 3 /TiO 2 is a dual catalyst, which could efficiently degrade lignin. This catalytic hydrogenation system can reduce solid products to less than 1%, while giving a high liquid product yield of 93%. Catalytic hydrocracking of kraft lignin at 320 °C for 6 h gave 93% liquid product with 0.5% solid product. Most of this liquid product was soluble in petroleum ether (60% of 93%), which is a clear liquid and comprises mainly of monomeric and dimeric degradation products. These results demonstrated that the combination of the two catalysts is an efficient catalyst for liquefaction of lignin, with little char formation (∼1%). This concept has the potential to produce valuable chemicals and fuels from lignin under moderate conditions. [ABSTRACT FROM AUTHOR]

A novel carbon solid acid catalyst was synthesized by the sulfonation of carbonaceous material which was prepared by carbonization of sucrose using 4-BDS as a sulfonating agent. TEM, N 2 adsorption–desorption, elemental analysis, XPS and FT-IR were used to characterize the catalyst. Then, the catalyst was applied for the conversion of xylose and corn stalk into furfural in GVL. The influence of the reaction time, temperature and dosage of catalyst on xylose dehydration were also investigated. The Brønsted acid catalyst exhibited high activity in the dehydration of xylose, with a high furfural yield of 78.5% at 170 °C in 30 min. What’s more, a 60.6% furfural yield from corn stalk was achieved in 100 min at 200 °C. The recyclability of the sulfonated carbon catalyst was perfect, and it could be reused for 5 times without the loss of furfural yields. [ABSTRACT FROM AUTHOR]