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Three-step conversion of Indulin AT to muconic acid under mild conditions

Li, Kena LU orcid ; Almqvist, Henrik LU and Hulteberg, Christian LU orcid (2021) In Biomass and Bioenergy 153.
Abstract

The conversion of technical lignin into valuable chemicals is important for the complete utilization of lignocellulose. The kraft process dominates the pulp industry, and large amounts of kraft lignin are produced worldwide. However, the complexity of lignin limits its valorization. In this study, a kraft lignin, Indulin AT, was depolymerized under base conditions, and the effects of substrate loading, NaOH concentration, temperature, and hydrogen peroxide on depolymerization were investigated. The production of aromatic monomers is favored by a continuous flow process, even with a very short reaction time (2 min vs. 30 min in a batch reactor). Higher temperature and NaOH concentration led to a higher degree of depolymerization, and... (More)

The conversion of technical lignin into valuable chemicals is important for the complete utilization of lignocellulose. The kraft process dominates the pulp industry, and large amounts of kraft lignin are produced worldwide. However, the complexity of lignin limits its valorization. In this study, a kraft lignin, Indulin AT, was depolymerized under base conditions, and the effects of substrate loading, NaOH concentration, temperature, and hydrogen peroxide on depolymerization were investigated. The production of aromatic monomers is favored by a continuous flow process, even with a very short reaction time (2 min vs. 30 min in a batch reactor). Higher temperature and NaOH concentration led to a higher degree of depolymerization, and thus more guaiacol and vanillin. A guaiacol yield of 5.1% was obtained after depolymerization of 5 wt% of lignin and 2 wt% of NaOH at 200 °C with a residence time of 2 min. When taking the whole operation, including the cost and depolymerization efficiency, into consideration, the concentration, lignin loading of 4 wt% of lignin, NaOH concentration of 2 wt%, and the temperature of 210 °C were chosen as the optimal conditions for the production of a guaiacol-rich fraction. The permeate obtained by ultrafiltration of the depolymerized Indulin AT sample contained a higher amount of guaiacol, which was quantitatively converted to muconic acid using an engineered strain of Pseudomonas putida KT2440. The three-step process in this work involves base-catalyzed depolymerization, ultrafiltration, and biological conversion represent an efficient approach to convert Indulin AT lignin into muconic acid.

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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Depolymerization, Guaiacol, Indulin AT, Kraft lignin, Muconic acid, Pseudomonas putida KT2440
in
Biomass and Bioenergy
volume
153
article number
106232
pages
9 pages
publisher
Elsevier
external identifiers
  • scopus:85115655242
ISSN
0961-9534
DOI
10.1016/j.biombioe.2021.106232
project
STEPS – Sustainable Plastics and Transition Pathways, Phase 2
language
English
LU publication?
yes
id
4dc58c86-0df0-4ae5-b8ef-826b830854eb
date added to LUP
2021-10-07 16:54:45
date last changed
2023-12-22 03:20:31
@article{4dc58c86-0df0-4ae5-b8ef-826b830854eb,
  abstract     = {{<p>The conversion of technical lignin into valuable chemicals is important for the complete utilization of lignocellulose. The kraft process dominates the pulp industry, and large amounts of kraft lignin are produced worldwide. However, the complexity of lignin limits its valorization. In this study, a kraft lignin, Indulin AT, was depolymerized under base conditions, and the effects of substrate loading, NaOH concentration, temperature, and hydrogen peroxide on depolymerization were investigated. The production of aromatic monomers is favored by a continuous flow process, even with a very short reaction time (2 min vs. 30 min in a batch reactor). Higher temperature and NaOH concentration led to a higher degree of depolymerization, and thus more guaiacol and vanillin. A guaiacol yield of 5.1% was obtained after depolymerization of 5 wt% of lignin and 2 wt% of NaOH at 200 °C with a residence time of 2 min. When taking the whole operation, including the cost and depolymerization efficiency, into consideration, the concentration, lignin loading of 4 wt% of lignin, NaOH concentration of 2 wt%, and the temperature of 210 °C were chosen as the optimal conditions for the production of a guaiacol-rich fraction. The permeate obtained by ultrafiltration of the depolymerized Indulin AT sample contained a higher amount of guaiacol, which was quantitatively converted to muconic acid using an engineered strain of <i>Pseudomonas putida</i> KT2440. The three-step process in this work involves base-catalyzed depolymerization, ultrafiltration, and biological conversion represent an efficient approach to convert Indulin AT lignin into muconic acid.</p>}},
  author       = {{Li, Kena and Almqvist, Henrik and Hulteberg, Christian}},
  issn         = {{0961-9534}},
  keywords     = {{Depolymerization; Guaiacol; Indulin AT; Kraft lignin; Muconic acid; Pseudomonas putida KT2440}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Biomass and Bioenergy}},
  title        = {{Three-step conversion of Indulin AT to muconic acid under mild conditions}},
  url          = {{http://dx.doi.org/10.1016/j.biombioe.2021.106232}},
  doi          = {{10.1016/j.biombioe.2021.106232}},
  volume       = {{153}},
  year         = {{2021}},
}