The Impact of Single Amino Acids on Growth and Volatile Aroma Production by Saccharomyces cerevisiae Strains

Abstract

Nitrogen availability and utilization by Saccharomyces cerevisiae significantly influence fermentation kinetics and the production of volatile compounds important for wine aroma. Amino acids are the most important nitrogen source and have been classified based on how well they support growth. This study evaluated the effect of single amino acids on growth kinetics and major volatile production of two phenotypically different commercial wine yeast strains in synthetic grape must. Four growth parameters, lag phase, maximum growth rate, total biomass formation and time to complete fermentation were evaluated. In contrast with previous findings, in fermentative conditions, phenylalanine and valine supported growth well and asparagine supported it poorly. The four parameters showed good correlations for most amino acid treatments, with some notable exceptions. Single amino acid treatments resulted in the predictable production of aromatic compounds, with a linear correlation between amino acid concentration and the concentration of aromatic compounds that are directly derived from these amino acids. With the increased complexity of nitrogen sources, linear correlations were lost and aroma production became unpredictable. However, even in complex medium minor changes in amino acid concentration continued to directly impact the formation of aromatic compounds, suggesting that the relative concentration of individual amino acids remains a predictor of aromatic outputs, independently of the complexity of metabolic interactions between carbon and nitrogen metabolism and between amino acid degradation and utilization pathways.

Impact of Nutrient Availability on the Fermentation and Production of Aroma Compounds Under Sequential Inoculation With M. pulcherrima and S. cerevisiae

“…In the case of moderate and high initial YAN contents, the residual nitrogen level was higher at the time of S. cerevisiae addition, between 95 and 190 mg N/L, but some specific nitrogen sources, such as branched amino acids, glutamate and glutamine, were exhausted, in accordance with the sequence of the consumption of nitrogen sources by M. pulcherrima previously reported by Su et al (2020). As a consequence, the nitrogen resources available to promote further S. cerevisiae implantation were mainly composed of proline, tryptophan, glycine and alanine, which support the growth and fermentation of the yeast poorly (Godard et al, 2007;Fairbairn et al, 2017). Overall, early inoculation with M. pulcherrima resulted in a 1.7-to 2-fold decrease in the maximal fermentation rate of S. cerevisiae.…”

Co-fermentation Involving Saccharomyces cerevisiae and Lactobacillus Species Tolerant to Brewing-Related Stress Factors for Controlled and Rapid Production of Sour Beer

“…Amino acid metabolism is essential for flavor formation, both by S. cerevisiae (Hernández-Orte et al, 2006) and lactobacilli (Smit et al, 2005), and amino acid availability can be directly correlated with production of compounds such as esters and higher alcohols. The amino acid metabolism is highly complex, even in single strain fermentations, as the same metabolic intermediates are involved multiple metabolic pathways (Fairbairn et al, 2017). Prediction of the sensory output from the amino acid composition of wort, resulting from a mixed fermentation with S. cerevisiae and Lactobacillus is not possible, and a through discussion of this is beyond the scope of the current study.…”

Nitrogen Preferences during Alcoholic Fermentation of Different Non-Saccharomyces Yeasts of Oenological Interest

“…Nitrogen compounds are the nutrients mostly assimilated by yeasts, after carbon compounds, during alcoholic fermentation. They are involved in the metabolism and growth of yeasts, affecting the correct evolution of the fermentation [1,13], and the production of volatile compounds [14][15][16]. In grape musts, nitrogen composition can be highly variable, both in concentration and in the types of nitrogen compounds present [17].…”