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Effective utilisation and processing of renewable resources

Fermentation, isolation, separation and purification are key processes in the overall workflow that enable the prepartion of substances from renewable resources and biotechnological production. Scientists at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart are focusing on the development of new innovative methods.

The preparation of substances from renewable resources and biotechnological production has a long tradition at the Fraunhofer IGB. Numerous IGB innovations are used in industrial applications. However, it is not always just the requirements of industry that spark off certain projects, sometimes the projects come about by pure accident. One example of a development that came about due to fortuitous circumstances, is a method for extracting thaumatin, a low-calorie protein sweetener found in katemfe fruit from Africa. Dr. Wolfgang Krischke, head of the Department of Environmental Biotechnology and Bioprocess Engineering at the IGB explains how the researchers discovered the method: “One day a welfare worker lost her way on the premises of the Stuttgart-based Fraunhofer Institute and we got talking, and that was how we found out about the OCAP project and the katemfe plant."

Dr. Wolfgang Krischke is the head of the Department of Environmental Biotechnology and Bioprocess Engineering at the IGB in Stuttgart. © Fraunhofer IGB

OCAP (Oda-Kotoamso Community Agroforestry Project) is a project that focuses on the sustained cultivation of a former wood-felling area in Ghana. The project is one of the projects funded by the Deutsche Investitions- und Entwicklungs-GmbH. The katemfe is among the plants that proved to be extremely suited to cultivation on wood-felling areas. The plant's fruits contain thaumatin, a substance that is 2000 times sweeter than sugar and has hardly any calories. The commercial use of this plant is highly interesting because thaumatin is approved as a food supplement in the EU," explains Krischke who has developed an industrial method for obtaining a natural sweetener from plant material in the country of origin.

The IGB experts initially developed a laboratory-scale process and subsequently transferred it to an African manufacturing facility. The process starts with the mechanical pulping of the fruit shells, followed by liquid extraction and purification of the proteins using modern membrane technology. After extraction, the proteins are dried so that they can be stored and transported. The researchers from Stuttgart have achieved excellent results: the thaumatin production plant has been operational since 2004 and is able to produce a natural sweetener that fully conforms with the quality requirements of the foodstuffs authorisation regulation.

From biological material to plastics

The sweetener thaumatin is produced from katemfe fruit using industrial processing and purification technologies developed by Fraunhofer IGB scientists. © Fraunhofer IGB

The production and application of lactic acid is a less exotic project. The sugar required for the production of lactic acid can be produced from renewable resources such as sugar beet, wheat, rye and maize. Wood can also be used for producing certain types of sugars. "Wood is the basic raw material in our biorefinery. Our colleagues from the Fraunhofer Institute for Chemical Technology ICT in Pfinztal close to Karlsruhe have developed a method for the pulping of wood that generates hemicellulose, cellulose and lignin," said Krischke. A great deal of thought goes into finding the most efficient and optimised method for the processing of raw material; the scientists concentrate on the use of state-of-the-art methods that promise the greatest economic benefit.

Fermentation methods are used to convert sugar into lactic acid and other industrially interesting compounds such as acetate, propanediol or butanediol. The IGB scientists are also working hard to increase the efficiency of fermentation. Some of the projects are funded with money from the BMBF "BioIndustry 2021" initiative in the "Industrial processes with biogenic building blocks and performance proteins" cluster.

Huge demand for highly pure yields

Bipolar electrodialysis, a method developed at the IGB, is an electrochemical membrane method for the production of acids and bases from salt solutions. © Fraunhofer IGB
Fermentation always requires the researchers to separate the entire product yield from the fermentation broth without affecting the products’ properties. IGB researchers have developed a membrane method that can be adapted to specific requirements, for example the purification of proteins. Bipolar electrodialysis is another one of the researchers’ developments. This electrochemical membrane method converts salt solutions into acids and bases and is used, for example, in the manufacture of free acid from fermentatively produced substances such as lactate and the recovery of acids and bases from salt solutions.

New centre for industry-oriented pilot projects

Other Fraunhofer Institutes besides the IGB also focus on the utilisation and processing of renewable resources. “The Fraunhofer Institute for Chemical Technology ICT is working on these issues in its own projects and also in cooperation with us,” said Krischke. The Chemical-Biotechnological Process Centre CBP that is currently being erected in Leuna is designed to bring together the skills of the various partners at one single location. The 50-million-euro project is being implemented in cooperation with InfraLeuna GmbH, the Leuna chemical location operating company, and with Linde KCA Dresden as general engineering procurement construction contractor. “The IGB group is setting up numerous industrial pilot plants for the production of resources with a vast number of organisms and enzymes. Many other companies are involved in these projects,” said Krischke.

Further information:
Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB
Department of Environmental Biotechnology and Bioprocess Engineering
Dr. Wolfgang Krischke
Nobelstraße 12
70569 Stuttgart
Tel.: +49 (0)711 970-4218
E-mail: wolfgang.krischke[at]igb.fraunhofer.de
Website address: https://www.biooekonomie-bw.de/en/articles/news/effective-utilisation-and-processing-of-renewable-resources