Metabonomic analysis reveals enhanced growth and ethanol production of brewer's yeast by wheat gluten hydrolysates and potassium supplementation

Wheat gluten hydrolysates (WGH) and KCl were used to examine their effects on fermentation performances and physiological characteristics of brewer's yeast during very high gravity (VHG) fermentation. Results showed that all supplementations exhibited a notable promotion in yeast growth, glucose utilization, ethanol production, and physiological characteristics. Combination supplementation of 0.3% WGH and 0.5% KCl showed the best promotion effect with 6.38%, 9.41% and 8.68% of increases in biomass, glucose utilization and ethanol production, respectively. Moreover, combination addition of WGH and KCl also enhanced significantly membrane integrity and mitochondrial functionality of brewer's yeast. Amino acid compositions of WGH and intracellular metabolites analysis indicated that active nitrogen metabolism and high levels of stress resistant substances might be responsible for the improvement of growth and fermentation performances in brewer's yeast by nutrient supplementation.