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Beer is popular in many countries – the average German drank 104 litres in 2016. The Belgians produce some 1,000 different varieties of the amber nectar. But no matter where it takes place, the brewing process generates large amounts of waste: around 400,000 tons in Europe and as much as 39 million tons worldwide. Part of this is fed to animals, as the brewery by-products, known in the trade as spent grain, contain valuable nutrients: protein, maltose, fibre, enzymes, vitamins and fats. Scientists are now also interested in these constituents. In the cross-border BIOVAL project (only in German), researchers at universities in France, Luxembourg, Belgium and Germany are exploring how these brewery by-products can be put to good use.
Rival for packaging material based on crude oil
After a year of intense research, the scientists at Technische Universität Kaiserslauten are optimistic: "We are able to break the spent grain down into its constituent parts", explains bioprocess engineer Roland Ulber. These components could be used as the basis for bioplastics, for example. The professor and his team are looking at the chemical products that are created when fungi and bacteria are added to further ferment the spent grain. The researchers are experimenting with polylactic acids as the basis for environmentally-friendly packaging material. From an ecological perspective, this could seriously rival products based on crude oil.
The three-year European project is being run from Belgium. The scientists are in close contact by e-mail and meet on a regular basis. "It goes without saying that we also share the samples to be tested between us", explains Professor Werner Thiel.
New products for the chemical industry
His group at the Department of Inorganic Chemistry in Kaiserslautern is researching the chemical reactions and how to accelerate them. As far as the spent grain is concerned, the scientists are interested above all in their water-insoluble fats, which originally come from the grain kernel. "We analyse their composition and try to turn them into products that might be of interest to the chemical industry", says chemistry professor Thiel. The first step is to split off the glycerine and fatty acids, which contain relatively large quantities of linoleic acid. He explains that catalytic reactions can be used to extract the basic building blocks for polymers from them. "Ultimately, this would result in a polymer being produced from a renewable resource that would otherwise be discarded or, at best, used as animal fodder."
Impact on health
Another research group led by Professor Elke Richling is studying whether substances from spent grain can have effects on the human organism. A food chemist, she and her team are exploring whether or not the substances are harmful to human health. Furthermore, there is evidence to suggest that various substances contained in spent grain can prevent sugar being absorbed into the bloodstream, explains doctoral student Daniela Becker. This is why they are also looking at any possible impact on human sugar metabolism.
Research project BIOVAL (only in German)
The European project "BIOVAL – Implementation of a value-adding chain based on brewery by-products" is intended to run for three years. On the German side, three departments at Technische Universität Kaiserslautern are involved, as is Saarland University. Other project partners are the University of Liège and CELABOR in Belgium, the University of Lorraine in France and the Luxembourg Institute of Health.www.mv.uni-kl.de