During the brewing process, yeast is added to initiate fermentation, converting sugar to alcohol and carbon dioxide (CO2). Before full maturation of the beer, the excess yeast is collected and can be re-used in the brewing process up to around six times. After this, it becomes brewer?s spent yeast (BSY) - the second biggest by-product of the brewing process (15% of total by-products generated).
BSY contains a high level of nutrients and there are several technologies that can turn this waste into a valuable resource. However, BSY is highly susceptible to rapid contamination and spoilage as a result of the activity of microorganisms. This has hampered the large-scale use of some technologies for reusing BSY. Drying the spent yeast can make it last longer, but this is an expensive process that requires large amounts of energy.
Currently outside of Europe, the brewer AB InBev has extensive drying operations to produce dried brewer?s yeast, which can be sold for use in human food and animal nutrition (mostly pet food). However, most of the BSY produced by the company in Europe (some 125 000 tonnes/yr) is sold in its wet form as inexpensive animal feed to farmers ? only 10% is processed in drying installations due to the costs involved.
LIFE YEAST aims to develop a new methodology to process (hydrolise) BSY into valuable constituents that can be used as raw materials with high market value in a wide range of industrial applications. The constituent parts include customised yeast extract (CYE), yeast cell wall (YCW), partially autolysed yeast (PAY), and bioactive peptides.
The project will test, optimise and scale-up the processing of BSY over the first 13 months of the project. After 21 months, it aims to have demonstrated the use of CYE and YCW in the brewing (AB InBev) and pharmaceuticals (VLPbio) industries to enhance the efficiency of the fermentation process and as a source of nitrogen. At the end of the project, a full engineering package will be developed to transfer the technology to AB InBev breweries.
It also aims to explore new partnerships and the potential of the following additional industrial applications:
The project aims to contribute to the shift towards a more circular economy in one of the priority areas of the EU Circular Economy Action Plan: food waste. It will also directly contribute to implementation of the Water Framework Directive (WFD) by fostering water efficient technologies and practices.
Expected results: During the project lifetime: Replacement of commercially available yeast extract with customised yeast extract derived from spent yeast to provide savings of 346 kWh of electricity, 50 kg of glucose and 1 150 litres of water.
Once the new process is fully operational, the project expects to: