VTT Technical Research Centre of Finland has developed more efficient ways of extracting useful substances – fats, sugars, peptides and phenolic compounds – from brewer's spent grain (BSG). Fractions extracted from BSG could have numerous applications in the manufacture of food, drinks and fuel, and in the chemical industry.
The brewing of 100 litres of beer generates approximately 15 kg of BSG. At present, BSG primarily ends up as animal feed. It contains high amounts of proteins, dietary fibres, fats and lignin, which could be extracted and reused in new food products, drinks, feeds, fuels and chemical industry products. However, the complex composition and structure of BSG makes it a challenging material for refining.
VTT has developed thermochemical pretreatment and enzymatic treatment methods for effectively refining BSG into various fractions enriched in sugars, proteins, lipids, phenolic compounds or lignin. The research was performed as part of the international IPTOSS project (2012–2015), coordinated by VTT.
Depending on the mashing process, BSG contains up to 23 per cent protein on dry matter basis. However, the protein is poorly soluble, which makes it difficult to extract. Protein recovery can be substantially increased by applying an enzymatic treatment that breaks down the proteins into soluble peptides. Preliminary techno-economic and sustainability evaluations performed during the IPTOSS project suggest that extraction of protein from BSG has good commercialisation opportunities.
Another interesting opportunity lies in using carbohydrate-degrading enzymes to extract sugars from BSG and return them to the beer manufacturing process. The first brewery tests at VTT have yielded promising results.
In addition to VTT, research partners in the IPTOSS project included the University of Applied Sciences and Arts Northwestern Switzerland (FHNW) and BionActis Ltd (Switzerland). The project was financed by Tekes - the Finnish Funding Agency for Innovation and Bundesamt für Umwelt (BAFU) and sponsored by Roal Ltd, the PBL Brewing Laboratory and St1 Biofuels Ltd.
The total budget of the project was EUR 1 million, approximately half of which was financed by Tekes and BAFU.