UN SDG
Call for SR&TD Project Grants - 2017
€238.739,25
Valuation of brewers spent yeast polysaccharides for food and biomedical applications
Elisabete Verde Martins Coelho
Universidade de Aveiro
Agricultural Biotechnology

Industrial Biotechnology
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Brewer?s spent yeast (BSY) is a major by-product from beer industry. It contains a large amount of polysaccharides, namely, mannoproteins and glucans. Recent work developed in our group reported the structural features of Saccharomyces pastorianus yeast cell walls, with peculiar glycosidic-linkage compositions, which are induced by the fermentation processes and the adaptation of the yeasts to the alcohol medium. Also, depending on the species used and the number of yeast reutilizations, it is possible to recover different type and structures of polysaccharides for food applications. For example, Saccharomyces cerevisiae is a source of (1?3)-glucans or (1?4)-glucans, while S. pastorianus is a source of mannoproteins. BSY showed a high variability depending on the yeasts strain/species and reutilization.
The first step for BSY valuation is the polysaccharides recovery, which can be performed by microwave assisted water extraction, and their detailed structural analysis in order to have information to define new applications in the field of food and medical industry. This brewery industry by-product contains polysaccharides that hold potential for food and biomedical applications. Thus, this project will develop food ingredients with emulsifier properties and will study the basis of a universal BSY microcapsule carrier (BSYM) that could be used for non-invasive oral intake cancer treatment. In order to ensure that BSYM are able to be recognized the project firstly purposes a detailed structural characterization of brewing spent yeasts cell wall features and then determine the structural organization of cell wall polysaccharides, and know more about the novel (?1?4)-linkages recently described. Due to modifications that occur in yeast cell wall, such as the presence of cellulose-like glucans, the BSYM, depending on the structure presented could, or not, be able to interact with Dectin-1 and then internalized. Secondly, the study of interaction of BSY polysaccharides with dectin-1 will be accessed by complementary approaches 1) using glucan microarrays with the team member A Palma at NOVA and 2) by BSYM recognition in immune cells, murine macrophages and dendritic cells, afterwards, using human dendritic cells and intestinal epithelial cells, using the facilities and synergies of IBMC.
The project proposes the valuation of the BSY for novel applications that could emerge from its unique structural features. In this way, valuate BSY as a coproduct should be important to produce yeasts in controlled conditions containing polysaccharides with characteristics suitable to obtain food ingredients, biomaterials, and microcapsules. The microcapsules are obtained after cell wall soluble polysaccharides extraction, where BSY preserve their three-dimensional structure as hollow spheres. Through the BSY knowledge will be possible to identify process conditions that modulate yeast, for the expression of molecular structures allowing the proposed applications.
brewers spent yeastfood ingredientsbiomaterialsoral delivery system