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Title: Development and Characterization of a High-Solids Deacetylation Process

Abstract

Dilute-acid pretreatment has proven to be a robust means of converting herbaceous feedstock to fermentable sugars. However, it also releases acetic acid, a known fermentation inhibitor, from acetyl groups present in the biomass. A mild, dilute alkaline extraction stage was implemented prior to acid pretreatment to separate acetic acid from the hydrolysate sugar stream. This step, termed deacetylation, improved the glucose and xylose yields from enzymatic hydrolysis and ethanol yields from fermentation of the sugars relative to the control experiments using dilute-acid pretreatment of native corn stover without deacetylation. While promising, deacetylation as it was historically practiced is conducted at low solids loadings, and at fixed conditions. Thus, many questions have been left unanswered, including the relationship between sodium hydroxide and solids loading, and acetate and xylan solubilization, as well as the impact of temperature and residence time on the process efficacy. A central composite experiment was designed to evaluate the impact of solids loading, sodium hydroxide loading, reaction time and temperature during deacetylation on the acetate and xylan solubilization of corn stover. Using the ANOVA test, it became apparent that neither of the responses was significantly impacted by the solids loading, while the reaction time was a minor factormore » - the responses were largely driven by reaction temperature and the sodium hydroxide loading. Based on the results, we successfully demonstrated the ability to transition the low-solids (10 % w/w) deacetylation process to a higher-solids process (30 % w/w) with minimal impact on the ability to extract acetate from biomass. Conditions were selected to minimize xylose loss during deacetylation, while also removing 70 % of acetyl groups. The impact of selected conditions on the enzymatic hydrolysis and fermentation was further investigated. In conclusion, evaluation of the whole-process impact demonstrated that despite the upfront reduction in carbohydrate loss during deacetylation, the overall process sugar yields were depressed by the high-solids, low alkali process relative to the historical control. Consequently, ethanol titers were reduced, though strong fermentation performance was still observed, indicating that 70 % acetate removal is sufficient to depress acetic acid concentrations to a level that does not substantially inhibit ethanol fermentation by rZymomo nas.« less

Authors:
 [1];  [2];  [3];  [3]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States). Transportation and Hydrogen Systems Center
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States). National Bioenergy Center
  3. tional Renewable Energy Lab. (NREL), Golden, CO (United States). National Bioenergy Center
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Transportation Office. Bioenergy Technologies Office
OSTI Identifier:
1334736
Report Number(s):
NREL/JA-5400-67518
Journal ID: ISSN 2043-7129
Grant/Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Sustainable Chemical Processes
Additional Journal Information:
Journal Volume: 4; Journal ID: ISSN 2043-7129
Publisher:
Springer
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; deacetylated corn stover; dilute acid; bioethanol; pretreatment; enzymatic hydrolysis; fermentation; deacetylation

Citation Formats

Shekiro, III, Joseph, Chen, Xiaowen, Smith, Holly, and Tucker, Melvin P. Development and Characterization of a High-Solids Deacetylation Process. United States: N. p., 2016. Web. doi:10.1186/s40508-016-0049-6.
Shekiro, III, Joseph, Chen, Xiaowen, Smith, Holly, & Tucker, Melvin P. Development and Characterization of a High-Solids Deacetylation Process. United States. doi:10.1186/s40508-016-0049-6.
Shekiro, III, Joseph, Chen, Xiaowen, Smith, Holly, and Tucker, Melvin P. Fri . "Development and Characterization of a High-Solids Deacetylation Process". United States. doi:10.1186/s40508-016-0049-6. https://www.osti.gov/servlets/purl/1334736.
@article{osti_1334736,
title = {Development and Characterization of a High-Solids Deacetylation Process},
author = {Shekiro, III, Joseph and Chen, Xiaowen and Smith, Holly and Tucker, Melvin P.},
abstractNote = {Dilute-acid pretreatment has proven to be a robust means of converting herbaceous feedstock to fermentable sugars. However, it also releases acetic acid, a known fermentation inhibitor, from acetyl groups present in the biomass. A mild, dilute alkaline extraction stage was implemented prior to acid pretreatment to separate acetic acid from the hydrolysate sugar stream. This step, termed deacetylation, improved the glucose and xylose yields from enzymatic hydrolysis and ethanol yields from fermentation of the sugars relative to the control experiments using dilute-acid pretreatment of native corn stover without deacetylation. While promising, deacetylation as it was historically practiced is conducted at low solids loadings, and at fixed conditions. Thus, many questions have been left unanswered, including the relationship between sodium hydroxide and solids loading, and acetate and xylan solubilization, as well as the impact of temperature and residence time on the process efficacy. A central composite experiment was designed to evaluate the impact of solids loading, sodium hydroxide loading, reaction time and temperature during deacetylation on the acetate and xylan solubilization of corn stover. Using the ANOVA test, it became apparent that neither of the responses was significantly impacted by the solids loading, while the reaction time was a minor factor - the responses were largely driven by reaction temperature and the sodium hydroxide loading. Based on the results, we successfully demonstrated the ability to transition the low-solids (10 % w/w) deacetylation process to a higher-solids process (30 % w/w) with minimal impact on the ability to extract acetate from biomass. Conditions were selected to minimize xylose loss during deacetylation, while also removing 70 % of acetyl groups. The impact of selected conditions on the enzymatic hydrolysis and fermentation was further investigated. In conclusion, evaluation of the whole-process impact demonstrated that despite the upfront reduction in carbohydrate loss during deacetylation, the overall process sugar yields were depressed by the high-solids, low alkali process relative to the historical control. Consequently, ethanol titers were reduced, though strong fermentation performance was still observed, indicating that 70 % acetate removal is sufficient to depress acetic acid concentrations to a level that does not substantially inhibit ethanol fermentation by rZymomo nas.},
doi = {10.1186/s40508-016-0049-6},
journal = {Sustainable Chemical Processes},
issn = {2043-7129},
number = ,
volume = 4,
place = {United States},
year = {2016},
month = {5}
}

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Works referenced in this record:

Integrated conversion of agroindustrial residue with high pressure CO 2 within the biorefinery concept
journal, January 2014

  • Morais, Ana R. C.; Mata, Ana C.; Bogel-Lukasik, Rafal
  • Green Chem., Vol. 16, Issue 9
  • DOI: 10.1039/C4GC01093K

Coupling alkaline pre-extraction with alkaline-oxidative post-treatment of corn stover to enhance enzymatic hydrolysis and fermentability
journal, January 2014

  • Liu, Tongjun; Williams, Daniel L.; Pattathil, Sivakumar
  • Biotechnology for Biofuels, Vol. 7, Issue 1
  • DOI: 10.1186/1754-6834-7-48

Lime pretreatment of crop residues bagasse and wheat straw
journal, September 1998

  • Chang, Vincent S.; Nagwani, Murlidhar; Holtzapple, Mark T.
  • Applied Biochemistry and Biotechnology, Vol. 74, Issue 3
  • DOI: 10.1007/BF02825962

The effect of reaction time and temperature during heterogenous alkali deacetylation on degree of deacetylation and molecular weight of resulting chitosan
journal, June 2003

  • Tsaih, Ming Larng; Chen, Rong H.
  • Journal of Applied Polymer Science, Vol. 88, Issue 13
  • DOI: 10.1002/app.11986

Summary of findings from the Biomass Refining Consortium for Applied Fundamentals and Innovation (CAFI): corn stover pretreatment
journal, June 2009


High Xylose Yields from Dilute Acid Pretreatment of Corn Stover Under Process-Relevant Conditions
journal, January 2009

  • Weiss, Noah D.; Nagle, Nicholas J.; Tucker, Melvin P.
  • Applied Biochemistry and Biotechnology, Vol. 155, Issue 1-3
  • DOI: 10.1007/s12010-008-8490-y

Pretreatment technologies for an efficient bioethanol production process based on enzymatic hydrolysis: A review
journal, July 2010


Alkaline Pretreatment of Corn Stover: Bench-Scale Fractionation and Stream Characterization
journal, May 2014

  • Karp, Eric M.; Donohoe, Bryon S.; O’Brien, Marykate H.
  • ACS Sustainable Chemistry & Engineering, Vol. 2, Issue 6, p. 1481-1491
  • DOI: 10.1021/sc500126u

Methods for Pretreatment of Lignocellulosic Biomass for Efficient Hydrolysis and Biofuel Production
journal, April 2009

  • Kumar, Parveen; Barrett, Diane M.; Delwiche, Michael J.
  • Industrial & Engineering Chemistry Research, Vol. 48, Issue 8, p. 3713-3729
  • DOI: 10.1021/ie801542g

Scale-up and integration of alkaline hydrogen peroxide pretreatment, enzymatic hydrolysis, and ethanolic fermentation
journal, December 2011

  • Banerjee, Goutami; Car, Suzana; Liu, Tongjun
  • Biotechnology and Bioengineering, Vol. 109, Issue 4
  • DOI: 10.1002/bit.24385

Optimizing hammer mill performance through screen selection and hammer design
journal, January 2013

  • Yancey, Neal; Wright, Christopher T.; Westover, Tyler L.
  • Biofuels, Vol. 4, Issue 1
  • DOI: 10.4155/bfs.12.77

Characterization of pilot-scale dilute acid pretreatment performance using deacetylated corn stover
journal, January 2014

  • Shekiro III, Joseph; Kuhn, Erik M.; Nagle, Nicholas J.
  • Biotechnology for Biofuels, Vol. 7, Issue 1
  • DOI: 10.1186/1754-6834-7-23

Sodium Hydroxide Pretreatment of Switchgrass for Ethanol Production
journal, March 2010

  • Xu, Jiele; Cheng, Jay J.; Sharma-Shivappa, Ratna R.
  • Energy & Fuels, Vol. 24, Issue 3
  • DOI: 10.1021/ef9014718

Imidazole: Prospect Solvent for Lignocellulosic Biomass Fractionation and Delignification
journal, December 2015

  • Morais, Ana Rita C.; Pinto, Joana Vaz; Nunes, Daniela
  • ACS Sustainable Chemistry & Engineering, Vol. 4, Issue 3
  • DOI: 10.1021/acssuschemeng.5b01600