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Production of high concentrated cellulosic ethanol by acetone/water oxidized pretreated beech wood

BACKGROUND: Lignocellulosic biomass is an abundant and inexpensive resource for biofuel production. Alongside its biotechnological conversion, pretreatment is essential to enable efficient enzymatic hydrolysis by making cellulose susceptible to cellulases. Wet oxidation of biomass, such as acetone/w...

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Autores principales: Katsimpouras, Constantinos, Kalogiannis, Konstantinos G., Kalogianni, Aggeliki, Lappas, Angelos A., Topakas, Evangelos
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5331700/
https://www.ncbi.nlm.nih.gov/pubmed/28265300
http://dx.doi.org/10.1186/s13068-017-0737-9
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author Katsimpouras, Constantinos
Kalogiannis, Konstantinos G.
Kalogianni, Aggeliki
Lappas, Angelos A.
Topakas, Evangelos
author_facet Katsimpouras, Constantinos
Kalogiannis, Konstantinos G.
Kalogianni, Aggeliki
Lappas, Angelos A.
Topakas, Evangelos
author_sort Katsimpouras, Constantinos
collection PubMed
description BACKGROUND: Lignocellulosic biomass is an abundant and inexpensive resource for biofuel production. Alongside its biotechnological conversion, pretreatment is essential to enable efficient enzymatic hydrolysis by making cellulose susceptible to cellulases. Wet oxidation of biomass, such as acetone/water oxidation, that employs hot acetone, water, and oxygen, has been found to be an attractive pretreatment method for removing lignin while producing less degradation products. The remaining enriched cellulose fraction has the potential to be utilized under high gravity enzymatic saccharification and fermentation processes for the cost-competing production of bioethanol. RESULTS: Beech wood residual biomass was pretreated following an acetone/water oxidation process aiming at the production of high concentration of cellulosic ethanol. The effect of pressure, reaction time, temperature, and acetone-to-water ratio on the final composition of the pretreated samples was studied for the efficient utilization of the lignocellulosic feedstock. The optimal conditions were acetone/water ratio 1:1, 40 atm initial pressure of 40 vol% O(2) gas, and 64 atm at reaction temperature of 175 °C for 2 h incubation. The pretreated beech wood underwent an optimization step studying the effect of enzyme loading and solids content on the enzymatic liquefaction/saccharification prior to fermentation. In a custom designed free-fall mixer at 50 °C for either 6 or 12 h of prehydrolysis using an enzyme loading of 9 mg/g dry matter at 20 wt% initial solids content, high ethanol concentration of 75.9 g/L was obtained. CONCLUSION: The optimization of the pretreatment process allowed the efficient utilization of beech wood residual biomass for the production of high concentrations of cellulosic ethanol, while obtaining lignin that can be upgraded towards high-added-value chemicals. The threshold of 4 wt% ethanol concentration that is required for the sustainable bioethanol production was surpassed almost twofold, underpinning the efficient conversion of biomass to ethanol and bio-based chemicals on behalf of the biorefinery concept. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13068-017-0737-9) contains supplementary material, which is available to authorized users.
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spelling pubmed-53317002017-03-06 Production of high concentrated cellulosic ethanol by acetone/water oxidized pretreated beech wood Katsimpouras, Constantinos Kalogiannis, Konstantinos G. Kalogianni, Aggeliki Lappas, Angelos A. Topakas, Evangelos Biotechnol Biofuels Research BACKGROUND: Lignocellulosic biomass is an abundant and inexpensive resource for biofuel production. Alongside its biotechnological conversion, pretreatment is essential to enable efficient enzymatic hydrolysis by making cellulose susceptible to cellulases. Wet oxidation of biomass, such as acetone/water oxidation, that employs hot acetone, water, and oxygen, has been found to be an attractive pretreatment method for removing lignin while producing less degradation products. The remaining enriched cellulose fraction has the potential to be utilized under high gravity enzymatic saccharification and fermentation processes for the cost-competing production of bioethanol. RESULTS: Beech wood residual biomass was pretreated following an acetone/water oxidation process aiming at the production of high concentration of cellulosic ethanol. The effect of pressure, reaction time, temperature, and acetone-to-water ratio on the final composition of the pretreated samples was studied for the efficient utilization of the lignocellulosic feedstock. The optimal conditions were acetone/water ratio 1:1, 40 atm initial pressure of 40 vol% O(2) gas, and 64 atm at reaction temperature of 175 °C for 2 h incubation. The pretreated beech wood underwent an optimization step studying the effect of enzyme loading and solids content on the enzymatic liquefaction/saccharification prior to fermentation. In a custom designed free-fall mixer at 50 °C for either 6 or 12 h of prehydrolysis using an enzyme loading of 9 mg/g dry matter at 20 wt% initial solids content, high ethanol concentration of 75.9 g/L was obtained. CONCLUSION: The optimization of the pretreatment process allowed the efficient utilization of beech wood residual biomass for the production of high concentrations of cellulosic ethanol, while obtaining lignin that can be upgraded towards high-added-value chemicals. The threshold of 4 wt% ethanol concentration that is required for the sustainable bioethanol production was surpassed almost twofold, underpinning the efficient conversion of biomass to ethanol and bio-based chemicals on behalf of the biorefinery concept. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13068-017-0737-9) contains supplementary material, which is available to authorized users. BioMed Central 2017-02-28 /pmc/articles/PMC5331700/ /pubmed/28265300 http://dx.doi.org/10.1186/s13068-017-0737-9 Text en © The Author(s) 2017 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
Katsimpouras, Constantinos
Kalogiannis, Konstantinos G.
Kalogianni, Aggeliki
Lappas, Angelos A.
Topakas, Evangelos
Production of high concentrated cellulosic ethanol by acetone/water oxidized pretreated beech wood
title Production of high concentrated cellulosic ethanol by acetone/water oxidized pretreated beech wood
title_full Production of high concentrated cellulosic ethanol by acetone/water oxidized pretreated beech wood
title_fullStr Production of high concentrated cellulosic ethanol by acetone/water oxidized pretreated beech wood
title_full_unstemmed Production of high concentrated cellulosic ethanol by acetone/water oxidized pretreated beech wood
title_short Production of high concentrated cellulosic ethanol by acetone/water oxidized pretreated beech wood
title_sort production of high concentrated cellulosic ethanol by acetone/water oxidized pretreated beech wood
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5331700/
https://www.ncbi.nlm.nih.gov/pubmed/28265300
http://dx.doi.org/10.1186/s13068-017-0737-9
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