Technology platform: Separation technologies

In nature, most of the organic and inorganic substances which are used as starting materials for products are mixtures of substances. Chemical synthesis also usually produces mixtures of substances or products that are contaminated with by-products. A key task in most processes in chemistry and biotechnology is therefore the separation of molecules from mixtures, either to obtain or purify substances or to remove interfering by-products.

Fraunhofer IGB has established a wide range of different separation processes and has the corresponding apparatus and equipment available both on a laboratory and pilot scale. Membrane and adsorption processes, electrophysical and thermal processes, but also crystallization, extraction and chromatography processes are constantly being further developed and optimized for various applications within the scope of our own research work.

A unique selling proposition of our institute is the possibility to combine these processes flexibly – if necessary with other classical processes such as centrifugation or flotation  – and to integrate them into process chains. This know-how can also be used for water treatment, recycling or in food processing technology.

Established separation technologies

Membrane processes

At Fraunhofer IGB we develop novel membranes for the treatment of aqueous solutions (membrane adsorbers for the separation of micropollutants or heavy metals, membranes for forward osmosis) and for gas separation (separation of O2). In addition, we are working on the development of membrane reactors that allow the direct integration of chemical reactions with substance separations. 

Compound separation by electric fields

In a number of processes newly developed at IGB, the separation of substances is based on the interaction of charged particles with an electric field. The movement of ions and molecules in the electric field is largely determined by their charge and mobility. This means that their separation is based on electrophoretic properties. The IGB designs various processes for different applications, tailored to the requirements of the respective separation problem, e.g. free-flow electrophoresis, electro-membrane filtration and electrodialysis.

Extraction technologies

Liquid extraction is used to extract valuable substances (biosurfactants, itaconic acid, malic acid, xylonic acid, long-chain dicarboxylic acids, furan dicarboxylic acid) from fermentation broths.

For the extraction of ingredients from microalgae, we at the Fraunhofer IGB have established pressure liquid extraction (PLE) as a batch high-pressure process. Algae constituents of different polarity are extracted with solvents or solvent mixtures of corresponding polarity at temperatures up to 150°C. The scale-up of the technology is currently under way.

Chromatography

For the development and implementation of purification processes for proteins in bacterial or eukaryotic fermentation broths as well as other protein-containing liquids, various chromatographic methods on a preparative and analytical scale are available.

Biosurfactants and basic chemicals produced by fermentation are also purified by chromatographic methods. Mannosylerythritol lipids, for example, are first obtained by separation and extraction from the fermentation broth. To separate oily residues, the extract is processed by chromatography (stationary phase: silica gel, mobile phase: solvent).

Application fields

Downstream processing

A large number of the separation processes presented here is used for the purification of products from biotechnological processes.

Water treatment

We have optimized membrane filtration and adsorption processes, electrophysical and also thermal separation processes for efficient water and wastewater treatment.

Recycling

For us, the recycling of material flows and the recovery of recyclable materials are part of sustainable waste management.

Food processing technology

With electro-membrane filtration we can separate valuable proteins from whey into functional fractions.