Model Compounds Study for the Mechanism of Horseradish Peroxidase-Catalyzed Lignin Modification
- 9 Downloads
Horseradish peroxidase (HRP) has demonstrated high activity for the modification of lignin. In this paper, several lignin model compounds with different functional groups and linkages are selected to investigate the reactivity of HRP-catalyzed lignin modification. The phenolic groups of lignin model compounds are indispensable for the HRP-catalyzed modification process. The introduction of the sulfomethylated methyl group or methoxyl group could facilitate or inhibit the modification, respectively. The oxidative coupling activity of α-O-4 lignin model compounds is higher than that of β-O-4 compounds. Meanwhile, the free energy obtained by density functional theory (DFT) is used to verify the results of the experimental study, and the order of preference for linkages is β-5 > β-β > β-O-4 in most cases. In addition, electron cloud density and steric hindrance of lignin model compounds have crucial effects on the oxidation and modification processes. Finally, the mechanism of HRP-catalyzed lignin modification is proposed.
KeywordsLignin Horseradish peroxidase Lignin modification Density functional theory
The authors would like to acknowledge the financial support of the National Key Research and Development Program of China (2018YFB1501503), National Natural Science Foundation of China (21878114, 21706079, 21690083, 21576106), Natural Science Foundation of Guangdong Province of China (2018B030311052, 2017B090903003), and State Key Laboratory of Pulp and Paper Engineering (201828).
Compliance with Ethical Standards
The authors declare they have no competing interests.
- 6.Amin, F. R., Khalid, H., Zhang, H., Rahman, S. U., Zhang, R. H., Liu, G. Q., & Chen, C. (2017). Pretreatment methods of lignocellulosic biomass for anaerobic digestion. AMB Express, 7(1), 72. https://doi.org/10.1186/s13568-017-0375-4.
- 12.Wang, J. H., Feng, J. J., Jia, W. T., Chang, S., Li, S. Z., & Li, Y. X. (2015). Lignin engineering through laccase modification: A promising field for energy plant improvement. Biotechnology for Biofuels, 8, 145. https://doi.org/10.1186/s13068-015-0331-y.