Effect of Different Zinc Sources and Concentrations on the Biomass Yield of Saccharomyces cerevisiae Yeast

Zinc incorporation and the growth of Saccharomyces cerevisiae were investigated in a culture supplemented with three inorganic zinc salts, i.e. zinc sulphate, zinc chloride and zinc nitrate. The cultivation was performed on a yeast extract peptone dextrose (YEPD) broth medium. The growth of yeast was carried out at different concentrations of zinc, i.e. 0, 30, 60, 90 and 120 mg 100 ml^-1. It was found that the addition of different zinc sources at 30 mg 100 ml^-1 concentration produced higher biomass yield ranging 1.00-1.03 g from 100 ml^-1 of cultivation medium, while higher zinc concentration in the medium caused significantly lower yields of yeast biomass. The amount of zinc in yeast cells was determined by an atomic absorption spectrometer (AAS). The highest amount of zinc in yeast cells was achieved when added in the form of zinc sulphate at a concentration of 120 mg 100 ml^-1. The increment of intracellular zinc was up to 9889.67 mg kg^-1 of biomass.