Magnesium capability to attenuate the toxicity of aluminum on the growth of Saccharomyces cerevisiae PE-2

Abstract

Summary The magnesium (Mg) capability to attenuate the toxicity of aluminum (Al) for the trehalose content, anaerobic growth, viability and budding rate of Saccharomyces cerevisiae, was studied in this work. Fermentations were carried out in triplicate with sterilized and diluted sugar cane media (4% total reducing sugars/pH 4.0) containing different Al (0.0, 50, 100 and 150 mg L-1) and Mg (0.0, 50 and 100 mg L-1) concentrations. The media were inoculated with 1 mL of 1% (wet basis) yeast suspension and incubated at 30ºC, 70 rpm for 20 hours in orbital shaker. At specific times during fermentation portions of cell suspension were taken out and the biomass concentration, yeast viability, budding rate and trehalose content on cells determined. The increase of Al levels, from 0.0 up to 150 mg L-1, showed a reduction on the yeast growth of approximately 95%, 55% and 18% as Mg increased from 0.0 to 50 and 100 mg L-1, respectively. The trehalose content experienced its lowest reduction when greater amounts of Mg were added to the fermentation process. Cell viability showed greater reductions as the content of Al in the media increased. Magnesium effectively protected yeast cells against the deleterious effects of Al on cell growth, viability, budding and trehalose content.