Effective pretreatment of lignin-rich coconut wastes using a low-cost ionic liquid
File(s)
Published version
Author(s)
Anuchi, Samson
Campbell, kyra
Hallett, Jason
Type
Journal Article
Abstract
Coconut husks and shells are underutilised agricultural feedstocks in the bio-based industry. These biomass wastes have a higher lignin content than other woody biomass and have excellent potential as raw materials for the production of lignin-based materials. This work demonstrates the performance of a low-cost protic ionic liquid, N,N,N-dimethylbutylammonium hydrogen sulfate ([DMBA][HSO4]), for ionoSolv pretreatment of coconut husk and shell at 150 °C for 45 – 90 minutes and 170 °C for 15 - 60 minutes. Optimum pretreatment conditions were observed at 170 °C and 45 minutes for both feedstocks. At these conditions, [DMBA][HSO4] was able to remove almost 77 wt.% of the lignin from the husk; leaving a cellulosic rich pulp behind, which released 82 % of the theoretical maximum glucose after enzymatic saccharification. The pretreated shell, by comparison, achieved 82 wt.% lignin removal and 89 % glucose yield and these higher values could be attributed to the highly porous structure of coconut shell cell walls. The cleavage of the β-O-4 aryl ether linkages of lignin followed by extensive C-C condensation in the lignin at longer pretreatment times was shown by HSQC NMR analysis. This extensive condensation was evidenced by molecular weights > 10 000 g/mol exhibited by lignin precipitated after pretreatment at high temperature and long times. The high degree of lignin removal and high glucose release from both feedstocks demonstrate that [DMBA][HSO4] is an excellent ionic liquid for fractionation of very lignin-rich biomass.
Date Issued
2022-04-12
Date Acceptance
2022-03-14
Citation
Scientific Reports, 2022, 12
ISSN
2045-2322
Publisher
Nature Publishing Group
Journal / Book Title
Scientific Reports
Volume
12
Copyright Statement
© TheAuthor(s) 2022. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
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Subjects
Biomass
Cocos
Glucose
Hydrolysis
Ionic Liquids
Lignin
Cocos
Lignin
Glucose
Biomass
Hydrolysis
Ionic Liquids
Publication Status
Published
Article Number
ARTN 6108