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Potassium Leakage as a Lethality Index of Phenol and the Effect of Solute and Water Activity
Author(s) -
KROLL R. G.,
ANAGNOSTOPOULOS G. D.
Publication year - 1981
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1981.tb00878.x
Subject(s) - phenol , chemistry , dilution , chromatography , aqueous solution , equilibrium constant , potassium , partition coefficient , reaction rate constant , glycerol , kinetics , inorganic chemistry , organic chemistry , thermodynamics , physics , quantum mechanics
Continuous monitoring of K + leakage from Serratia marcescens on exposure to phenol in aqueous and solute‐containing suspensions was followed by a K + selective electrode. At each phenol concentration, the suspension reached an equilibrium between the internal and external K + as the result of cell leakage. The K + concentration at equilibrium was constant for each cell suspension and independent of the phenol concentration that induced it. Phenol concentration affected only the rate of K + release and the time ‘ t Kmax’to reach the equilibrium state. The cell number affected the maximum K + concentration at equilibrium and the rate of K + leakage in such a way that ‘ t Kmax’was constant at a given phenol concentration. Therefore, the ratio t Kmax/ D value was constant at phenol concentrations below 1.2%. When the water activity of the phenol solutions was reduced by addition of sucrose and glycerol. the kinetics of K + leakage compared consistently with that of lethality by phenol. Consequently, the concentration coefficient ‘ n ’derived from the log‐log plot of t Kmax. and phenol concentrations was influenced by the solutes and the resulting water activity similarly as that derived from D values. Thus, ‘ n ’increased in the presence of suerose and decreased in the presence of glycerol progressively with their concentration. It was concluded that t Kmax could be used as a lethality parameter with predominantly membrane active antimicrobial agents.