Accumulation and Release of Metal Ions by Brewer’s Yeast During Successive Fermentations

Poreda Aleksander¹, Antkiewicz Piotr, Tuszyński Tadeusz and Małgorzata Makarewicz
¹University of Agriculture in Krakow, Department of Fermentation Technology and Technical Microbiology, ul. Balicka 122, 31-149 Krakow, Poland
Corresponding author. E-mail: aporeda@ar.krakow.pl

J. Inst. Brew. 115(1), 78–83, 2009 | VIEW ARTICLE

ABSTRACT
Magnesium, zinc and calcium are the elements that are involved in the regulation of metabolic activity of yeast and/or other processes such as flocculation and cell division. The requirements for specific ions may be subject to changes in successive fermentations performed by the same biomass. The aim of this work was to analyze the changes in calcium, magnesium and zinc concentration in malt broth (9°P) and in the yeast over four successive fermentations. For all ionic species analysed, the qualitative uptake and release patterns observed during subsequent fermentations were similar. In the lag phase of the fermentation, yeast cells accumulated the metal ions under investigation, in order to liberate them later to an extent that depended on the specific metal and fermentation number. Some differences were noted when qualitative comparison of these processes was performed. During the first fermentation with the yeast culture, the maximum content of each ion in the yeast biomass was two to threefold higher than in the subsequent fermentations. Calcium, magnesium and zinc levels in the biomass did not exceed 1, 6 and 0.6 mg/g yeast dry weight respectively.

Key words:
bioaccumulation, brewer’s yeast, calcium, magnesium, metal ions, release, zinc.