Title: Increasing the Carbohydrate Output of Bamboo Using a Combinatorial Pretreatment

Abstract

Bamboo represents a family of highly lignified biomass with significant resistance to cellulolytic enzyme degradation, and typically, a severe thermochemical pretreatment is needed to overcome its recalcitrance for producing fermentable sugars. Combinatorial pretreatments with a low holding temperature and low alkali dosage were investigated in this study in an attempt to remove the impediments to the accessibility of bamboo cellulose to enzymes and enable the efficient conversion of hemicellulose. Upon autohydrolysis at 180 °C, more than half of the hemicellulose (~58%) was solubilized, contributing to further delignification in the subsequent dilute alkali extraction (DAE). The solubilized hemicellulose mainly existed in the form of soluble xylan, which, after a novel endo-β-1,4-xylanase hydrolysis, generated a large amount of xylo-oligosaccharides with the xylobiose and xylotriose proportion reaching 72.99%. After the fractionation with combinatorial pretreatments, cellulose and xylose enzymatic hydrolysis yields were 73.36 and 86.98%, respectively, representing increments of 22.42 and 43.15% compared with the sole autohydrolysis process. Fluorescence microscopy (FM) and confocal Raman microscopy (CRM) images revealed that these dramatic improvements were caused by the deconstruction of the bamboo cell walls, including separation of the adjacent cell walls, removal of hemicellulose and lignin, migration and redistribution of lignin, and the increased exposure ofmore » cellulose. In addition, lignin chemical structure variations during the combinatorial pretreatment were analyzed with gel permeation chromatography (GPC), 2D HSQC NMR, and ³¹P NMR, and the correlation between the lignin structure and enzymatic hydrolysis efficiency was investigated. In summary, this study highlighted the application of combinatorial pretreatments to maximize the carbohydrate output of bamboo and unveiled their mechanism that enabled the high-efficiency utilization of bamboo.« less

Authors:

Huang, Chen ^[1]; Fang, Guigan ^[2]; Zhou, Yang ^[3]; Du, Xinghu ^[3]; Yu, Longxiang ^[3]; Meng, Xianzhi  ^[4];

• Search DOE PAGES for author "Meng, Xianzhi"
• Search DOE PAGES for ORCID "0000-0003-4303-3403"

Li, Mi  ^[4];

• Search DOE PAGES for author "Li, Mi"
• Search DOE PAGES for ORCID "0000-0001-7523-1266"

Yoo, Chang Geun  ^[5];

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• Search DOE PAGES for ORCID "0000-0002-6179-2414"

Chen, Bingwei ^[3]; Zhai, Shengcheng ^[3]; Guan, Qiyuan  ^[6];

• Search DOE PAGES for author "Guan, Qiyuan"
• Search DOE PAGES for ORCID "0000-0003-0397-2545"

Yong, Qiang ^[3]; Ragauskas, Arthur J.  ^[7]

• Search DOE PAGES for author "Ragauskas, Arthur J."
• Search DOE PAGES for ORCID "0000-0002-3536-554X"

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+ Show Author Affiliations

1. Chinese Academy of Forestry, Nanjing (China); Nanjing Forestry Univ. (China); Univ. of Tennessee, Knoxville, TN (United States)
2. Chinese Academy of Forestry, Nanjing (China); Nanjing Forestry Univ. (China)
3. Nanjing Forestry Univ. (China)
4. Univ. of Tennessee, Knoxville, TN (United States)
5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); State Univ. of New York (SUNY), Syracuse, NY (United States)
6. Chinese Academy of Forestry, Nanjing (China)
7. Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Publication Date:

Wed May 06 00:00:00 EDT 2020

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1632074

Grant/Contract Number:  

AC05-00OR22725

Resource Type:

Accepted Manuscript

Journal Name:

ACS Sustainable Chemistry & Engineering

Additional Journal Information:

Journal Volume: 8; Journal Issue: 19; Journal ID: ISSN 2168-0485

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

09 BIOMASS FUELS