Capacities of binding magnesium ions by the Saccharomyces cerevisiae bakery yeast during cultivation in stationary conditions on the YPD (control) and YPD (experimental) media enriched in 0.25., 0.5 and 1.25 g Mg2+/dm3 from two salts: MgSO4 x 7H2O or MgCl2 x 6H2O were the subject of the study. The salts were added to the experimental media at the beginning of the cultivation or at the end of the logarithmic phase of yeast growth. Magnesium content was evaluated with ASA method in the centrifuged yeast biomass that had and had not been washed with deionized water. Magnesium content in the yeast cultivated in the experimental media was significantly higher than in the yeast cultivated in the control medium. It was stated that increased concentration of magnesium ions (from all sources used)in the experimental media caused higher amount of magnesium content in non-washed biomass cell although the differences were not always significant. The addition of magnesium ions at the end of logarithmic phase of growth did not influence the magnesium contents in cell biomass after 24 and 48 hours of cultivation in comparison with the media enriched at the beginning of cultivation (Tab. 1 and 2, Tab. 3 and 4.). The major part of magnesium was loosely bound with yeast cells what was proved by comparison of magnesium content in yeast biomass that had and had not been washed with deionized water. The type of magnesium salts as well as their concentration did not have a significant influence on the yeast cell biomass yield (Tab. 5 and 6).

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