The diversity of yeasts and yeast microorganisms on grapes and, consequently, in musts may be strongly influenced by using Cu2+ products. The effect of Cu2+ concentration on the growth of native yeast strains isolated from grapes and grape must of three grape varieties was studied. The growth of H. uvarum, P. kluyveri, P. kudriavzevii, C. californica, F. elegans, R. bacarum and Sc. crataegensis was inhibited in the presence of a minimum concentration of 0.5 mM Cu2+. The growth of S. cerevisiae, Cr. magnus, R. glutinis and Sp. pararoseus depended on the strain tested. The strains of A. pullulans, M. pulcherrima, C. oleophila, P. terricola, R. nothofagi and R. minuta were growing at increasing Cu2+ concentrations but their growth was reduced by prolongation of the lag phase compared with their growth in the absence of Cu2+. The growth reduction of ethanol-tolerant yeast strains at higher concentration of Cu ions shows the effect of the prolonged action of wine fermentation. Autochthonous yeast strains resistant to higher Cu2+ concentrations (C. oleophila, M. pulcherrima, R. minuta) appear to be an appropriate solution to reduction of Cu residues in the fermenting must.
The composition, main structural features and molecular properties of exopolysaccharides (EP) produced by Cryptococcus laurentii var. laurentii CCY 17-3-16 under optimal (EPo) and NaCI-stress conditions (EPs) as well as their subfractions isolated by gel chromatography were studied using chemical, FT-IR and NMR spectroscopy methods. The results showed that under stress conditions the yeast produced EP with a lower content of protein and phosphorus. In comparison to EPo, the EPs exhibited a substantially larger proportion of high molecular mass populations. NMR analysis of EPs revealed a higher degree of branching with single xylose side chains of the heteromannan components. The increase of the molecular mass and degree of branching of the macromolecular chains of the heteromannan components might in part be related to the function of EPs to protect the yeast cells from water loss and maintain growth conditions under the salt stress.
Závěrečná zpráva o řešení grantu Interní grantové agentury MZ ČR
29 l. : il. ; 32 cm
Studium perfusních roztoků a možností jejich zlepšení. XXX XXX XXX
- Konspekt
- Biologické vědy
- NLK Obory
- biochemie
- gastroenterologie
- biologie
- NLK Publikační typ
- závěrečné zprávy o řešení grantu IGA MZ ČR
