production of dicarboxylic acids from beech wood · pdf filefachbereich maschinenbau und...
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Fachbereich Maschinenbauund
Verfahrenstechnik
67,1%
26,3%
6,4% 0,2%Succinic Acid
Acet Acid
Formic Acid
Fumaric Acid
Production of Dicarboxylic Acids from Beech Wood Hydrolysates
http://www.mv.uni-kl.de/biovt/
T. Sieker, J. Bosch, A. Duwe, N. Tippkötter, R. Ulber
University of Kaiserslautern, Institute of Bioprocess Engineering, Gottlieb-Daimler-Straße 44, 67663 Kaiserslautern
1. Introduction
The itaconic acid production by Aspergillus terreus is known to be very sensitive against a wide range of inhibitors, including several salt ions. Due to this, nei-ther growth nor itaconic acid formation could be ob-served when fermenting the untreated beech wood hydrolsate. For the detoxification of the hydrolysates a combination of anion- and cation exchangers in their H+ and OH--forms is very efficient. Hydrolysates in different concentrations were pre-pared (H1: 100 g
pulp L-1, H2 & 3: 300 g
pulp L-1), detoxified
(H1 & 2: 0.2 gadsorber
mL-1, H3: 0.4 gadsorber
mL-1) and tested for itaconic acid formation (see figure 1). Ita-conic acid yields of 0.25 g g-1 (H1 & H2) and 0.47 g g-1 (H3) could be achieved from the hydrolysates based on the consumed substrates.
Fermentable sugars derived from wooden celluloses and hemicelluloses by enzymatic hydrolysis are a promising renewable feedstock for the chemical industry. Although the fermentation of these sugars to ethanol has often been shown in literature, the production of higher value-added products from hydroly-sates is often difficult and has to be examined in more detail. Examples for such products are itaconic and succinic acid. As part of the German lignocellulose biorefinery project their production from technical beech wood hydrolysates is presented.
2. Itaconic Acid Production
Support Code: 22019409
Figure 1: Itaconic acid formation (top) and monosaccharide consumption (bottom) during fermentations on detoxified hy-drolysates.
3. Succinic Acid Production
For the succinic acid production Actinobacillus succi-nogenes is used. In contrast to Aspergillus terreus, it grows well and produces succinic acid even on the untreated hydrolysates, requiring CO
2 as further sub-
strate. Glucose and Xylose are completely consumed and succinic acid is formed as the major product with a yield of 0.7 g g-1 at a productivity of 0.39 g L-1 h-1.
4. Conclusions and Outlook
Itaconic and succinic acid production using techni-cal beech wood hydrolysates have been implement-ed at high yields. Future work will focus on the use of hydrolysates with higher monosaccharide concen-trations to reach higher product concentrations and on the purification of the acids.
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Conc
entra
tion [
g L-1]
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ose,
Xylos
e, Su
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c acid
Cultivation time [h]
Figure 2: Succinic acid formation on beech wood hydrolysate.
Figure 3: Product distribution.
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H 1 H 2 H 3
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