Growth efficiency of Saccharomyces cerevisiae on glucose/ethanol media with a smooth change in the dilution rate (A-stat)

• Published in: Enzyme and microbial technology 1997-01, Vol.20 (3), p.174-181
• Main Authors: Paalme, T., Elken, R., Vilu, R., Korhola, M.
• Format: Article
• Language: English
• Subjects: Baker's yeast; Biological and medical sciences; Biotechnology; Ethanol; Fundamental and applied biological sciences. Psychology; Glucose; growth characteristics; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Q1; saccharomyces cerevisiae
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/S0141-0229(96)00114-7

The effects of the ethanol/glucose ratio on the growth characteristics ( μ max, Q O 2 max, Y XS, Y XO 2 , etc.) of Saccharomyces cerevisiae on mineral media were studied. The maximum specific growth rate of the strain, μ max, obtained in a continuous culture with a smooth increase in dilution rate (A-stat) was equal to 0.44 h −1 on glucose and 0.13 h −1 on ethanol mineral medium. The maximum value of the specific respiratory rate with six different glucoselethanol ratios remained in the range of 6–9 mmol O 2 h −1 g dwt −1. The residual concentration of ethanol up to concentrations of 4 g l −1 did not reduce the respiration rate markedly. The critical specific growth rate, μ crit, (l eth = 0) was 0.25 h −1 which was independent on the ethanol/glucose ratio in the feed medium. Higher growth rates than μ > 0.25 h −1 were supported by the fermentative use of glucose. The maximum growth yield, Y XS, increased from 0.57 on pure glucose to 0.68 on pure ethanol (C-mol C-mol −1). A practical maximum ratio of ethanol to glucose in Baker's yeast propagation was suggested to be 40–50% (C-mol C-mol −1).