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Visualization of Miscanthus × giganteus cell wall deconstruction subjected to dilute acid pretreatment for enhanced enzymatic digestibility
BACKGROUND: The natural recalcitrance of lignocellulosic plant cell walls resulting from complex arrangement and distribution of heterogeneous components impedes deconstruction of such cell walls. Dilute acid pretreatment (DAP) is an attractive method to overcome the recalcitrant barriers for render...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4513789/ https://www.ncbi.nlm.nih.gov/pubmed/26213569 http://dx.doi.org/10.1186/s13068-015-0282-3 |
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author | Ji, Zhe Zhang, Xun Ling, Zhe Zhou, Xia Ramaswamy, Shri Xu, Feng |
author_facet | Ji, Zhe Zhang, Xun Ling, Zhe Zhou, Xia Ramaswamy, Shri Xu, Feng |
author_sort | Ji, Zhe |
collection | PubMed |
description | BACKGROUND: The natural recalcitrance of lignocellulosic plant cell walls resulting from complex arrangement and distribution of heterogeneous components impedes deconstruction of such cell walls. Dilute acid pretreatment (DAP) is an attractive method to overcome the recalcitrant barriers for rendering enzymatic conversion of polysaccharides. In this study, the internodes of Miscanthus × giganteus, a model bioenergy crop, were subjected to DAP to yield a range of samples with altered cell wall structure and chemistry. The consequent morphological and compositional changes and their possible impact on saccharification efficiency were comprehensively investigated. The use of a series of microscopic and microspectroscopic techniques including fluorescence microscopy (FM), transmission electron microscopy (TEM) and confocal Raman microscopy (CRM)) enabled correlative cell wall structural and chemical information to be obtained. RESULTS: DAP of M. × giganteus resulted in solubilization of arabinoxylan and cross-linking hydroxycinnamic acids in a temperature-dependent manner. The optimized pretreatment (1% H(2)SO(4), 170°C for 30 min) resulted in significant enhancement in the saccharification efficiency (51.20%) of treated samples in 72 h, which amounted to 4.4-fold increase in sugar yield over untreated samples (11.80%). The remarkable improvement could be correlated to a sequence of changes occurring in plant cell walls due to their pretreatment-induced deconstruction, namely, loss in the matrix between neighboring cell walls, selective removal of hemicelluloses, redistribution of phenolic polymers and increased exposure of cellulose. The consequently occurred changes in inner cell wall structure including damaging, increase of porosity and loss of mechanical resistance were also found to enhance enzyme access to cellulose and further sugar yield. CONCLUSIONS: DAP is a highly effective process for improving bioconversion of cellulose to glucose by breaking down the rigidity and resistance of cell walls. The combination of the most relevant microscopic and microanalytical techniques employed in this work provided information crucial for evaluating the influence of anatomical and compositional changes on enhanced enzymatic digestibility. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13068-015-0282-3) contains supplementary material, which is available to authorized users. |
format | Online Article Text |
id | pubmed-4513789 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-45137892015-07-25 Visualization of Miscanthus × giganteus cell wall deconstruction subjected to dilute acid pretreatment for enhanced enzymatic digestibility Ji, Zhe Zhang, Xun Ling, Zhe Zhou, Xia Ramaswamy, Shri Xu, Feng Biotechnol Biofuels Research Article BACKGROUND: The natural recalcitrance of lignocellulosic plant cell walls resulting from complex arrangement and distribution of heterogeneous components impedes deconstruction of such cell walls. Dilute acid pretreatment (DAP) is an attractive method to overcome the recalcitrant barriers for rendering enzymatic conversion of polysaccharides. In this study, the internodes of Miscanthus × giganteus, a model bioenergy crop, were subjected to DAP to yield a range of samples with altered cell wall structure and chemistry. The consequent morphological and compositional changes and their possible impact on saccharification efficiency were comprehensively investigated. The use of a series of microscopic and microspectroscopic techniques including fluorescence microscopy (FM), transmission electron microscopy (TEM) and confocal Raman microscopy (CRM)) enabled correlative cell wall structural and chemical information to be obtained. RESULTS: DAP of M. × giganteus resulted in solubilization of arabinoxylan and cross-linking hydroxycinnamic acids in a temperature-dependent manner. The optimized pretreatment (1% H(2)SO(4), 170°C for 30 min) resulted in significant enhancement in the saccharification efficiency (51.20%) of treated samples in 72 h, which amounted to 4.4-fold increase in sugar yield over untreated samples (11.80%). The remarkable improvement could be correlated to a sequence of changes occurring in plant cell walls due to their pretreatment-induced deconstruction, namely, loss in the matrix between neighboring cell walls, selective removal of hemicelluloses, redistribution of phenolic polymers and increased exposure of cellulose. The consequently occurred changes in inner cell wall structure including damaging, increase of porosity and loss of mechanical resistance were also found to enhance enzyme access to cellulose and further sugar yield. CONCLUSIONS: DAP is a highly effective process for improving bioconversion of cellulose to glucose by breaking down the rigidity and resistance of cell walls. The combination of the most relevant microscopic and microanalytical techniques employed in this work provided information crucial for evaluating the influence of anatomical and compositional changes on enhanced enzymatic digestibility. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13068-015-0282-3) contains supplementary material, which is available to authorized users. BioMed Central 2015-07-25 /pmc/articles/PMC4513789/ /pubmed/26213569 http://dx.doi.org/10.1186/s13068-015-0282-3 Text en © Ji et al. 2015 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. |
spellingShingle | Research Article Ji, Zhe Zhang, Xun Ling, Zhe Zhou, Xia Ramaswamy, Shri Xu, Feng Visualization of Miscanthus × giganteus cell wall deconstruction subjected to dilute acid pretreatment for enhanced enzymatic digestibility |
title | Visualization of Miscanthus × giganteus cell wall deconstruction subjected to dilute acid pretreatment for enhanced enzymatic digestibility |
title_full | Visualization of Miscanthus × giganteus cell wall deconstruction subjected to dilute acid pretreatment for enhanced enzymatic digestibility |
title_fullStr | Visualization of Miscanthus × giganteus cell wall deconstruction subjected to dilute acid pretreatment for enhanced enzymatic digestibility |
title_full_unstemmed | Visualization of Miscanthus × giganteus cell wall deconstruction subjected to dilute acid pretreatment for enhanced enzymatic digestibility |
title_short | Visualization of Miscanthus × giganteus cell wall deconstruction subjected to dilute acid pretreatment for enhanced enzymatic digestibility |
title_sort | visualization of miscanthus × giganteus cell wall deconstruction subjected to dilute acid pretreatment for enhanced enzymatic digestibility |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4513789/ https://www.ncbi.nlm.nih.gov/pubmed/26213569 http://dx.doi.org/10.1186/s13068-015-0282-3 |
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