Anaerobic Biodegradation of Wheat Straw Lignin: The Influence of Wet Explosion Pretreatment

Large amounts of lignin residue is expected in the future when biorefineries for producing biofuels and bio-products will increase in numbers. It is, therefore, valuable to find solutions for using this resource for the sustained production of useful bioenergy or bio-products. Anaerobic digestion co...

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Main Authors: Muhammad Usman Khan, Birgitte Kiaer Ahring
Format: Article
Language:English
Published: MDPI AG 2021-09-01
Series:Energies
Subjects:
Online Access:https://www.mdpi.com/1996-1073/14/18/5940
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author Muhammad Usman Khan
Birgitte Kiaer Ahring
author_facet Muhammad Usman Khan
Birgitte Kiaer Ahring
author_sort Muhammad Usman Khan
collection DOAJ
description Large amounts of lignin residue is expected in the future when biorefineries for producing biofuels and bio-products will increase in numbers. It is, therefore, valuable to find solutions for using this resource for the sustained production of useful bioenergy or bio-products. Anaerobic digestion could potentially be an option for converting the biorefinery lignin into a valuable energy product. However, lignin is recalcitrant to biodegradation under anaerobic conditions unless the structure is modified. Wet oxidation followed by steam explosion (wet explosion) was previously found to make significant changes to the lignin structure allowing for biodegradation under anaerobic conditions. In this study, we examine the effect of wet explosion pretreatment for anaerobic digestion of wheat straw lignin under mesophilic (37 °C) conditions. Besides the biorefinery lignin produced from wheat straw, untreated lignin was further tested as feed material for anaerobic digestion. Our results showed that wet exploded lignin pretreated with 2% NaOH showed the highest lignin degradation (41.8%) as well as the highest methane potential of 157.3 ± 9.9 mL/g VS. The untreated lignin with no pretreatment showed the lowest methane yield of 65.8 ± 4.8 and only 3.5% of the lignin was degraded. Overall, increased severity of the pretreatment was found to enhance anaerobic degradation of lignin.
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spelling doaj.art-a7e6a27565894b0f994452053bf7cd6d2023-11-22T12:55:25ZengMDPI AGEnergies1996-10732021-09-011418594010.3390/en14185940Anaerobic Biodegradation of Wheat Straw Lignin: The Influence of Wet Explosion PretreatmentMuhammad Usman Khan0Birgitte Kiaer Ahring1Bioproducts, Sciences and Engineering Laboratory, Washington State University, Tri-Cities, Richland, WA 99354, USABioproducts, Sciences and Engineering Laboratory, Washington State University, Tri-Cities, Richland, WA 99354, USALarge amounts of lignin residue is expected in the future when biorefineries for producing biofuels and bio-products will increase in numbers. It is, therefore, valuable to find solutions for using this resource for the sustained production of useful bioenergy or bio-products. Anaerobic digestion could potentially be an option for converting the biorefinery lignin into a valuable energy product. However, lignin is recalcitrant to biodegradation under anaerobic conditions unless the structure is modified. Wet oxidation followed by steam explosion (wet explosion) was previously found to make significant changes to the lignin structure allowing for biodegradation under anaerobic conditions. In this study, we examine the effect of wet explosion pretreatment for anaerobic digestion of wheat straw lignin under mesophilic (37 °C) conditions. Besides the biorefinery lignin produced from wheat straw, untreated lignin was further tested as feed material for anaerobic digestion. Our results showed that wet exploded lignin pretreated with 2% NaOH showed the highest lignin degradation (41.8%) as well as the highest methane potential of 157.3 ± 9.9 mL/g VS. The untreated lignin with no pretreatment showed the lowest methane yield of 65.8 ± 4.8 and only 3.5% of the lignin was degraded. Overall, increased severity of the pretreatment was found to enhance anaerobic degradation of lignin.https://www.mdpi.com/1996-1073/14/18/5940lignocellulosic materialsanaerobic digestionwet explosion pretreatmentlignincellulosehemicellulose
spellingShingle Muhammad Usman Khan
Birgitte Kiaer Ahring
Anaerobic Biodegradation of Wheat Straw Lignin: The Influence of Wet Explosion Pretreatment
Energies
lignocellulosic materials
anaerobic digestion
wet explosion pretreatment
lignin
cellulose
hemicellulose
title Anaerobic Biodegradation of Wheat Straw Lignin: The Influence of Wet Explosion Pretreatment
title_full Anaerobic Biodegradation of Wheat Straw Lignin: The Influence of Wet Explosion Pretreatment
title_fullStr Anaerobic Biodegradation of Wheat Straw Lignin: The Influence of Wet Explosion Pretreatment
title_full_unstemmed Anaerobic Biodegradation of Wheat Straw Lignin: The Influence of Wet Explosion Pretreatment
title_short Anaerobic Biodegradation of Wheat Straw Lignin: The Influence of Wet Explosion Pretreatment
title_sort anaerobic biodegradation of wheat straw lignin the influence of wet explosion pretreatment
topic lignocellulosic materials
anaerobic digestion
wet explosion pretreatment
lignin
cellulose
hemicellulose
url https://www.mdpi.com/1996-1073/14/18/5940
work_keys_str_mv AT muhammadusmankhan anaerobicbiodegradationofwheatstrawlignintheinfluenceofwetexplosionpretreatment
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