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Enhancing Effect of Residual Lignins from D. Sinicus Pretreated with Fenton Chemistry on Enzymatic Digestibility of Cellulose
Author(s) -
Wu Kai,
Ying Wenjun,
Shi Zhengjun,
Yang Haiyan,
Zheng ZhiFeng,
Zhang JiaYan,
Yang Jing
Publication year - 2018
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201700880
Subject(s) - lignin , chemistry , adsorption , cellulose , cellulase , hydrolysis , bamboo , enzymatic hydrolysis , moiety , organic chemistry , nuclear chemistry , materials science , composite material
Abstract To screen and evaluate possible functional factors in the bamboo lignin moiety that could block non‐productive adsorption of enzyme proteins on lignin, milled wood lignin (MWL) and Fenton oxidized lignin (FOLs) were prepared and incorporated in the enzymatic hydrolysis of Avicel. The addition of MWL decreased the 72 h glucose yields of cellulose from 57.1 % to 45.3 %, while FOLs effectively improved the enzymatic digestibility up to 69.5 %, which was 22 % higher than the system without the use of FOLs. The adsorption affinity and binding strength of cellulase with FOLs were lower than that with MWL. After Fenton pretreatment, hydrophilicity of lignins increased due to formation of C−O− and O−C=O bonds. Furthermore, high surface negative charges on FOLs resulted in strong electrostatic repulsion against the negatively charged cellulases. Finally, analysis of FOLs with 13C and 2D‐HSQC NMR indicated that the cleavage of β‐O‐4 linkages and demethoxylation occurred, and that less condensed structures at the C β and C γ positions were observed. These oxidation reactions of the bamboo lignin lead to the formation of functional factors to alleviate irreversible adsorption of cellulase onto FOLs, and thus were responsible for promoting enzymatic digestibility efficiency.