Amino Acid and Ammonium Utilization by Saccharomyces cerevisiae Wine Yeasts From a Chemically Defined Medium

Abstract

The utilization of amino acids and ammonium by nine wine strains of Saccharomyces cerevisiae was systematically studied in a chemically defined medium resembling the composition of grape juice. Both quantitative and qualitative differences in the utilization of assimilable nitrogen were observed. The mean concentration of total nitrogen utilized during the catabolism of 1.11 M (200 g/L) glucose when all amino acids were in excess was 400 mg N/L with a range of 140 mg N/L. Nitrogen utilization was influenced by the presence of air in the fermentation headspace, ammonium supplementation and initial glucose concentration. The kinetics of utilization of individual amino acids varied between strains. However, arginine, serine, glutamate, threonine, aspartate and lysine typically comprised the bulk of the nitrogen consumed. Addition of ammonium delayed and reduced the extent of accumulation of most amino acids but increased the total nitrogen consumed.