S Guillou1, N El Murr. 1. Laboratoire d'Analyse Isotopique et Electrochimique de Métabolismes, Université de Nantes, Faculté des Sciences et des Techniques, Nantes, France.
Abstract
AIMS: The objectives of this study were to investigate the potential application of a low-amperage direct electric current as a non-thermal process for inactivation of Saccharomyces cerevisiae. METHODS AND RESULTS: Electric current was generated using a direct current power supply connected to a traditional electrochemical cell with two platinum electrodes immersed in conducting solution containing a population of S. cerevisiae. This treatment provoked inactivation of the yeast cells. The microbial destruction illustrated by D-values calculated from survival curves was shown to be proportional to the current amperage (i) (D varies from 1547 min to 140 min when i varies from 0.1 to 1 A, respectively). The efficacy of the treatment was shown to be better at pH < 7. Statistical analysis showed no significant effect (P > 0.05) of ionic strength on yeast lethality induced by electrolysis. CONCLUSIONS: The lethal effect of the electric treatment on S. cerevisiae in phosphate buffer was shown to be due to neither ohmic heating nor toxic hydrogen peroxide. A synergistic effect of temperature and electrolysis was observed when the temperature became lethal for the yeast. SIGNIFICANCE AND IMPACT OF THE STUDY: The method described for yeast lethality induced by electrolysis has potential for soft sterilization, particularly when combined with the synergistic effect of moderate heat.
AIMS: The objectives of this study were to investigate the potential application of a low-amperage direct electric current as a non-thermal process for inactivation of Saccharomyces cerevisiae. METHODS AND RESULTS: Electric current was generated using a direct current power supply connected to a traditional electrochemical cell with two platinum electrodes immersed in conducting solution containing a population of S. cerevisiae. This treatment provoked inactivation of the yeast cells. The microbial destruction illustrated by D-values calculated from survival curves was shown to be proportional to the current amperage (i) (D varies from 1547 min to 140 min when i varies from 0.1 to 1 A, respectively). The efficacy of the treatment was shown to be better at pH < 7. Statistical analysis showed no significant effect (P > 0.05) of ionic strength on yeast lethality induced by electrolysis. CONCLUSIONS: The lethal effect of the electric treatment on S. cerevisiae in phosphate buffer was shown to be due to neither ohmic heating nor toxic hydrogen peroxide. A synergistic effect of temperature and electrolysis was observed when the temperature became lethal for the yeast. SIGNIFICANCE AND IMPACT OF THE STUDY: The method described for yeast lethality induced by electrolysis has potential for soft sterilization, particularly when combined with the synergistic effect of moderate heat.
Authors: Lyliane F Trigueiro; Larissa M Silva; Luciana A B D Itto; Thiago M B F Oliveira; Artur J Motheo; Carlos A Martínez-Huitle; Janete J F Alves; Suely S L Castro Journal: Environ Sci Pollut Res Int Date: 2016-08-05 Impact factor: 4.223
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