Study of the toxic effect of short- and medium-chain monocarboxylic acids on the growth of Saccharomyces cerevisiae using the CO2-auxo-accelerostat fermentation system.
The effect of aliphatic monocarboxylic acids (formic, acetic, propionic, valeric, octanoic and decanoic acids) on the growth and metabolic activity of Saccharomyces cerevisiae S288C was studied, using continuous cultivation method - CO(2)-auxo-accelerostat with smooth increase in the concentration of added monocarboxylic acids. Slow increase in the concentration of these acids resulted in the rapid decrease in the growth yield (Y(ATP)) and specific growth rate (micro), however, the specific ATP production rate (Q(ATP)) increased or stayed almost constant. On the other hand, Q(ATP) decreased if the concentration of formic, acetic or decanoic acids was increased rapidly. The toxic effect of aliphatic monocarboxylic acids on the growth of S. cerevisiae was characterized and quantified from the respective dose-effect curves as the IC(50) value (mM) using two different endpoints: a decrease of 50% in the specific growth rate (IC(50 micro)) and a decrease of 50% in the growth yield based on ATP production (IC(50YATP)). The concentrations of formic, acetic, propionic, valeric, octanoic and decanoic acids causing the 50% reduction in the specific growth rate (IC(50 micro)) were, respectively, 18.1, 47.1, 33.6, 2.3, 0.16 and 0.07 mM. The IC(50 micro) values were notably lower (up to 5-fold) in case of a more rapid increase in the concentration of acid in the medium. The results of the CO(2)-auxo-accelerostat experiments show that the toxic effect depends not only on the nature of the monocarboxylic acid (lipophilicity) but also on the rate at which its concentration changes in the growth environment.
Kasemets
Kaja
K
National Institute of Chemical Physics and Biophysics, Laboratory of Molecular Genetics, Akadeemia tee 23, 12618 Tallinn, Estonia. kasemets@kbfi.ee
Kahru
Anne
A
Laht
Tiiu-Mai
TM
Paalme
Toomas
T
D000222:Adaptation, Physiological; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000935:Antifungal Agents / Q000494:pharmacology*; D002245:Carbon Dioxide; D002264:Carboxylic Acids / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005285:Fermentation; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D005520:Food Preservatives / Q000494:pharmacology; D007700:Kinetics; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
D000935:Antifungal Agents; D002264:Carboxylic Acids; D005520:Food Preservatives; D002245:Carbon Dioxide; D000255:Adenosine Triphosphate