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ERA-WoodWisdom: Controlled separation and conversion process for wood hemicelluloses (COSEPA)
Project
Project code: TI-AT-08-PID1619, 22002314
Contract period: 01.05.2014
- 30.04.2017
Budget: 291,428 Euro
Purpose of research: Applied research
For a better utilization of biomass, the development of processes to convert hemicelluloses to value-added products is necessary. Exemplarily, we focus on the important industry chemicals 2,3-butanediol and maleic acid. Sustainability plays an increasingly important role in industrial processes. Therefore, a sustainable alternative is needed that can replace fossil raw materials. Hemicelluloses as part of wood are available in large quantities. They do not compete with food production and, so far, they are only used in minor amounts in industry. The European joint project COSEPA will utilize the underused material hemicelluloses, starting with the separation and fractionation of wood to obtain pentoses for further refinement to different valuable products. The Thünen-Institute focusses on the development of a biotechnical process to produce 2,3-butanediol as well as the catalytic synthesis of maleic acid from pentoses. 2,3-butanediol is a possible bio-based feedstock for its further conversion to methyl ethyl ketone, currently used in quantities of 1.7 Mio tons/year for the production of paints and coatings. Maleic acid and maleic anhydride are important building blocks, mainly used for unsaturated polyesters and alkyd resins. They are produced in an amount of 1.5 Mio tons/year. With the development of new process technologies based on hemicelluloses, noteworthy amounts of fossil feedstocks can be saved and important steps towards bio-based economy are made. The biotechnological production of 2,3-butanediol is well known since the 19th century. The highest productivities as well as yields were achieved with the strains Klebsiella oxytoca and Klebsiella pneumoniae. However, as these strains belong to the pathogenic risk class 2 an industrial process using such microorganisms is hardly realizable due to high cost for safety precautions. With risk class 1 microorganisms, as Paenibacillus polymyxa and Bacillus licheniformis, it is also possible to achieve high yields of 2,3-butanediol using glucose as substrate. So far, there is only little information about the conversion of xylose to 2,3-butanediol with these microorganisms and the yields that can be reached are rather poor. However, as processes based on pentoses as carbon source are far less optimized the prospects of reaching high amounts of 2,3-butanediol are promising. In addition to the already known strains, a screening for new risk class 1 microorganisms capable to produce 2,3-butanediol will be carried out. The most promising strains will be further used for process optimization. In the end an efficient bioprocess for 2,3-butanediol production based on pentoses shall be established. Currently maleic acid is produced by catalytic vapor phase oxidation of different petrochemicals (benzene, butane, butene) with only moderate selectivities. In the COSEPA-Project we want to synthesize maleic acid using pentoses instead of fossil raw materials. The challenge is to develop an effective overall process consisting of the subsequent reaction steps hemicellulose - pentose - furfural - maleic acid. Hemicellulose hydrolysis to pentoses (especially xylose and arabinose) can be easily achieved by acid catalysis or with enzymes. Since 1921 xylose is used to synthesize furfural, the potentially most important intermediate on the way to maleic acid. In order to produce maleic acid from furfural, an oxidation is essential. Since 1935 catalytic vapor phase oxidation processes using oxygen are known. Those are disadvantageous due to the high temperatures needed. More gentle reaction conditions may be applied together with complex catalysts. To realize the final aim of a one-pot-synthesis of maleic acid directly from hemicellulose, the existing knowledge has to be transferred to our new reaction system and new, more efficient catalysts have to be developed.
Section overview
Subjects
- Forestry
- Process engineering
- Renewable Resources
