Abstract
Background: Understanding factors that govern lignocellulosic biomass recalcitrance is a prerequisite for designingefficient 2nd generation biorefining processes. However, the reasons and mechanisms responsible for quantitative differences in enzymatic digestibility of various biomass feedstocks in response to hydrothermal pretreatment at different severities are still not sufficiently understood.
Results: Potentially important lignocellulosic feedstocks for biorefining, corn stover (Zea mays subsp. mays L.), stalks of Miscanthus × giganteus, and wheat straw (Triticum aestivum L.) were systematically hydrothermally pretreated; each at three different severities of 3.65, 3.83, and 3.97, respectively, and the enzymatic digestibility was assessed.Pretreated samples of Miscanthus × giganteus stalks were the least digestible among the biomass feedstocks producing~24 to 66.6% lower glucose yields than the other feedstocks depending on pretreatment severity and enzymedosage. Bulk biomass composition analyses, 2D nuclear magnetic resonance, and comprehensive microarray polymer profiling were not able to explain the observed differences in recalcitrance among the pretreated feedstocks. However, methods characterizing physical and chemical features of the biomass surfaces, specifically contact angle measurements (wettability) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy (surfacebiopolymer composition) produced data correlating pretreatment severity and enzymatic digestibility, and they also revealed differences that correlated to enzymatic glucose yield responses among the three different biomass types.
Conclusion: The study revealed that to a large extent, factors related to physico-chemical surface properties, namely surface wettability as assessed by contact angle measurements and surface content of hemicellulose, lignin, and waxas assessed by ATR-FTIR rather than bulk biomass chemical composition correlated to the recalcitrance of the testedbiomass types. The data provide new insight into how hydrothermal pretreatment severity affects surface propertiesof key Poaceae lignocellulosic biomass and may help design new approaches to overcome biomass recalcitrance.
Results: Potentially important lignocellulosic feedstocks for biorefining, corn stover (Zea mays subsp. mays L.), stalks of Miscanthus × giganteus, and wheat straw (Triticum aestivum L.) were systematically hydrothermally pretreated; each at three different severities of 3.65, 3.83, and 3.97, respectively, and the enzymatic digestibility was assessed.Pretreated samples of Miscanthus × giganteus stalks were the least digestible among the biomass feedstocks producing~24 to 66.6% lower glucose yields than the other feedstocks depending on pretreatment severity and enzymedosage. Bulk biomass composition analyses, 2D nuclear magnetic resonance, and comprehensive microarray polymer profiling were not able to explain the observed differences in recalcitrance among the pretreated feedstocks. However, methods characterizing physical and chemical features of the biomass surfaces, specifically contact angle measurements (wettability) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy (surfacebiopolymer composition) produced data correlating pretreatment severity and enzymatic digestibility, and they also revealed differences that correlated to enzymatic glucose yield responses among the three different biomass types.
Conclusion: The study revealed that to a large extent, factors related to physico-chemical surface properties, namely surface wettability as assessed by contact angle measurements and surface content of hemicellulose, lignin, and waxas assessed by ATR-FTIR rather than bulk biomass chemical composition correlated to the recalcitrance of the testedbiomass types. The data provide new insight into how hydrothermal pretreatment severity affects surface propertiesof key Poaceae lignocellulosic biomass and may help design new approaches to overcome biomass recalcitrance.
| Original language | English |
|---|---|
| Article number | 49 |
| Journal | Biotechnology for Biofuels |
| Volume | 10 |
| Number of pages | 15 |
| ISSN | 1754-6834 |
| DOIs | |
| Publication status | Published - 2017 |
Bibliographical note
© The Author(s) 2017. This 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/public domain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Keywords
- Hydrothermal pretreatment
- Enzymatic hydrolysis
- Hemicellulose
- Wettability
- 2D nuclear magnetic resonance (NMR)
- Attenuated total reflectance-Fourier transform infrared (ATR-FTIR)
- Comprehensive microarray polymer profiling (CoMPP)
- Contact angle measurements