PROJECT DESCRIPTION
BACKGROUND
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.
OBJECTIVES
LIFE YEAST aimed 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 would test, optimise and scale-up the processing of BSY over the first 13 months of the project. After 21 months, it aimed 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 would be developed to transfer the technology to AB InBev breweries.
It also aimed to explore new partnerships and the potential of the following additional industrial applications:
- YCW as a probiotic in animal feed;
- PAY as a fermentation activator in the wine industry; and
- Bioactive peptides with health-stimulating and anti-oxidant properties in the food and cosmetics industries.
The project aimed 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 would also directly contribute to implementation of the Water Framework Directive (WFD) by fostering water efficient technologies and practices.
RESULTS
The LIFE YEAST project developed and adapted an extraction process for processing brewers’ spent yeast to obtain significant amounts of yeast extract, yeast cell wall and beta-glucans. This process was demonstrated on a laboratory scale using a litre of material and on a pilot scale of 30 litres. The extraction process was then optimised and scaled up on a demonstration scale of 100 to 200 litres.
The yeast extract produced was shown to be a good source of nitrogen for use in the pharmaceutical industry. Testing showed that the yeast extract can be used in any fermentation process for the production of therapeutic recombinant vaccines based on virus-like particles without restrictions and with the same results as commercial yeast extract. However, this new nitrogen source for fermentations does not comply will all the strict pharmaceutical standards as some are beyond the scope of the project.
The yeast extract also has the potential for application in the food sector. In fact, the beneficiaries produced several prototypes foodstuffs, including a protein beverage powder, a vegetable Bolognese sauce, gluten-free tomato crackers, cereal snacks with seeds and bouillon tablets. The products were assessed to have promising market potential.
The coordinating beneficiary AB InBev has drawn up plans for the replication of the technology in its breweries around the world. The roll out will start in those breweries with the greatest prospect of success and the shortest payback periods, as well as in those where relationships with potential partners have already been established. Samples of beer supplemented with the project’s yeast cell wall were considered superior in terms of flavour than other beers made from the commercially available yeast cell wall beer. Additionally, the project yeast extract improves beer fermentation when the malt content is low.
Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).
