Acid/alkali-catalyzed deep eutectic solvent pretreatment of corn straw for enhanced biohydrogen production
Wenlu Song, Jungang Jiang, Huixin Jiang, Chuantao Liu, Ying Dong, Xue Chen, Ling‐Ping Xiao
Abstract
Lignocellulose is considered as a potential source for biohydrogen production, however, the tough and rigid structure endow the lignin with high resistance to biodegradation. In this work, choline chloride/1,4-butanediol deep eutectic solvent (DES) pretreatment aiding with AlCl 3 /NaOH was developed to dissociate the lignin macromolecular structure of corn straw for promoting biohydrogen production. The results showed that alkali-catalyzed DES pretreatment reached a yield of biohydrogen production of 117.4 mL/g total solids (TS) in comparison with that of acid-catalyzed DES pretreatment (100.5 mL/g TS) at 100 °C for 3 h with 4.0 wt% alkali/acid dosage. The enhanced biohydrogen production was mainly ascribed to the higher lignin removal rate (81.3%) of alkali-catalyzed DES pretreatment, which facilitated subsequent enzymatic saccharification and dark fermentation of carbohydrate. Moreover, the recovered lignin obtained from this pretreatment displayed well-preserved β- O -4′ linkages (44.4/100Ar) with an appropriate molecular weight (1540 g/mol) and regular spherical particles. The new insights of this work may provide guidance for designing novel DES pretreatment toward bio-energy production from lignocellulose fractionation and component valorization.