The bamboo delignification saturation point in alkaline hydrogen peroxide pretreatment and its association with enzymatic hydrolysis

Chen Huang; Yunni Zhan; Jinyuan Cheng; Jia Wang; Xianzhi Meng; Guigan Fang; Arthur J Ragauskas

doi:10.1016/j.biortech.2022.127462

The bamboo delignification saturation point in alkaline hydrogen peroxide pretreatment and its association with enzymatic hydrolysis

Bioresour Technol. 2022 Sep:359:127462. doi: 10.1016/j.biortech.2022.127462. Epub 2022 Jun 11.

Authors

Chen Huang¹, Yunni Zhan¹, Jinyuan Cheng¹, Jia Wang², Xianzhi Meng³, Guigan Fang¹, Arthur J Ragauskas⁴

Affiliations

¹ Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry, Jiangsu Province Key Laboratory of Biomass Energy and Materials, Nanjing 210042.
² Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China.
³ Department of Chemical and Biomolecular Engineering, University of Tennessee Knoxville, Knoxville, TN 37996, USA.
⁴ Department of Chemical and Biomolecular Engineering, University of Tennessee Knoxville, Knoxville, TN 37996, USA; Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, The University of Tennessee Institute of Agriculture, Knoxville, TN 37996, USA; UTK-ORNL Joint Institute for Biological Science, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.

PMID: 35700894
DOI: 10.1016/j.biortech.2022.127462

Abstract

A delignification saturation point (DSP) was observed for bamboo alkaline hydrogen peroxide pretreatment (AHP). Lignin removal was increased from 52.23% to ∼70% when increasing H₂O₂ dosage from 0% to 2% at the optimum pH, but it cannot be further reinforced as increasing the H₂O₂. With partial lignin preserved, the glucan hydrolysis yield was found to have a ceiling of ∼80%. This study indicated a strong association between enzymatic digestibility and lignin removal. Anatomical analysis by fluorescence microscope and confocal Raman microscope revealed that the undegradable lignin was mainly existing in the cell corner of sclerenchyma fibers, causing the DSP in the bamboo AHP. Finally, the residual lignin in pretreated bamboo was characterized with GPC, HSQC NMR, and ³¹P NMR, which revealed the nature of DSP. This study could help to understand the lignin modification during the AHP and further contribute to the establishment of a chemical-saving biorefinery.

Keywords: Alkaline hydrogen peroxide pretreatment; Bamboo; Delignification saturation point; Enzymatic saccharification.

MeSH terms

Glucans
Hydrogen Peroxide*
Hydrolysis
Lignin* / chemistry

Substances

Glucans
Lignin
Hydrogen Peroxide