Bioresource Technology 2014-10-01

Mild alkali-pretreatment effectively extracts guaiacyl-rich lignin for high lignocellulose digestibility coupled with largely diminishing yeast fermentation inhibitors in Miscanthus.

Ming Li, Shengli Si, Bo Hao, Yi Zha, Can Wan, Shufen Hong, Yongbo Kang, Jun Jia, Jing Zhang, Meng Li, Chunqiao Zhao, Yuanyuan Tu, Shiguang Zhou, Liangcai Peng

Index: Bioresour. Technol. 169 , 447-54, (2014)

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Abstract

In this study, various alkali-pretreated lignocellulose enzymatic hydrolyses were evaluated by using three standard pairs of Miscanthus accessions that showed three distinct monolignol (G, S, H) compositions. Mfl26 samples with elevated G-levels exhibited significantly increased hexose yields of up to 1.61-fold compared to paired samples derived from enzymatic hydrolysis, whereas Msa29 samples with high H-levels displayed increased hexose yields of only up to 1.32-fold. In contrast, Mfl30 samples with elevated S-levels showed reduced hexose yields compared to the paired sample of 0.89-0.98 folds at p<0.01. Notably, only the G-rich biomass samples exhibited complete enzymatic hydrolysis under 4% NaOH pretreatment. Furthermore, the G-rich samples showed more effective extraction of lignin-hemicellulose complexes than the S- and H-rich samples upon NaOH pretreatment, resulting in large removal of lignin inhibitors to yeast fermentation. Therefore, this study proposes an optimal approach for minor genetic lignin modification towards cost-effective biomass process in Miscanthus. Copyright © 2014 Elsevier Ltd. All rights reserved.