engleski

Yeasts and mushrooms as a source of β-glucans

INTRODUCTION β-Glucans are glucose polymers that occur in different natural sources. Except their potential use in human and veterinary medicine, β-glucans can also find a wide variety of uses in the food and feed, pharmaceutical and chemical industries. Yeasts, mushrooms and algae are among the main sources of β-glucan. Yeast Saccharomyces cerevisiae is the most available eukaryotic microorganism utilized in biotechnology. Spent brewer’s yeast is by-product of beer production and it could be used as a cheap source of β-glucans. The most cultivated mushroom Agaricus bisporus (known as white button mushroom or champignon) is also valuable source of β-glucans. Waste champignon biomass, containing mainly lower parts of champignon stalks, is a secondary product which is gained during the harvesting stage. Although this material is edible, there is not a suitable market for its distribution in Croatia and therefore it could be used as a source of bioactive polysaccharides (e.g. β-glucans). METHODOLOGY Three different procedures have been used for isolation of water-insoluble β-glucans from spent brewer’s yeast: alkaline isolation (A), alkaline-acidic isolation (AA) and alkaline-acidic isolation with mannoprotein removal (AAM). The waste champignon biomass served as a raw material for isolation of soluble polysaccharides by water extraction and ethanol precipitation. RESULTS AND DISCUSSION The preparations obtained from brewer’s yeast and champignon waste had significantly different morphology, depending on the source for isolation, solubility, isolation procedure and the drying method applied. FT-IR spectra of all polysaccharide preparations showed typical spectral pattern of β-(1, 3)-glucan. Dry weight of all three isolated yeast β-glucans contained more than 90 % of total polysaccharides and the portion of β-glucan was 69.73 – 99.12 %. In air dried samples of crude polysaccharides, isolated from champignon waste, the portion of total carbohydrates and β-glucan were 44.18 % and 16.37 %, respectively. CONCLUSIONS The obtained results showed that spent brewer’s yeast and the waste biomass of Agaricus bisporus could be used as a raw material for isolation of β-glucans.

Agaricus bisporus; β-glucan; polysaccharides; Sacharomyces cerevisiae; yeast; waste biomass

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