Inactivation effect of sonication and chlorination on Saccharomyces cerevisiae. Calorimetric Analysis

Abstract

The inactivation effects of ultrasonic irradiation at 27.5 kHz and chlorination using sodium hypochlorite solution (NaOCl) on the growth of Saccharomyces cerevisiae (yeast cells) were investigated. In order to evaluate the effect of ultrasound on the growth of the yeast cells, calorimetric analysis was carried out in addition to colony counting. The heat evolution produced by the growth of yeast cells detected by calorimetry showed completely different patterns between sonication and chlorination. In case of sonication, the yeast cells were inactivated almost like a bactericidal effect, i.e. a quantitative change in cell number, at the beginning of sonication. It was similar to patterns obtained on simple dilution of yeast cells. In contrast, longer sonication increased the bacteriostatic effect, i.e. qualitative damage of the cell growth activity, together with the bactericidal effect. These results suggest that the cavitation caused by ultrasonic irradiation initially disrupted the cells located near the cavitation bubble which caused immediate cell death and the growth activity of the surviving cells was gradually damaged by further sonication. On the other hand, only a bacteriostatic effect was observed when the yeast cells were inactivated by chlorination.

Comparative real-time analysis of Saccharomyces cerevisiae cell viability, injury and death induced by ultrasound (20kHz) and heat for the application of hurdle technology

“…Using methylene blue as an indicator of S. cerevisiae metabolic status, others showed that intracellular cavitation caused early cell perturbation (Ciccolini et al, 1997;Lorincz, 2004;Petin et al, 1999). Early modification of cell contents prior to cell wall damage was indicated when calorimetry was used to observe changes in yeast cell metabolism (Tsukamoto et al, 2004a). It is likely that these injuries increase the sensitivity of S. cerevisiae to heating.…”

“…In addition, viable but nonculturable cells (VBNC) occur in a yeast population, and are not detected by standard plate counts (Boyd et al, 2003). Alternate methods used to gauge the response of S. cerevisiae to ultrasound suggest that metabolic changes consistent with possible injury occur in the organism prior to death (Borthwick, Coakley, Mc Donell, Nowtony, Benes, & Groschl, 2005;Ciccolini et al, 1997;Food Research International 47 (2012) 134-139 Lorincz, 2004Tsukamoto, Constantinoiu, Furuta, Nishimura, & Maeda, 2004a). To apply hurdle technology successfully, an understanding of the injury status of cells is important.…”

Study of butter fat content in milk on the inactivation of Listeria innocua ATCC 51742 by thermo-sonication

“…Several studies have also reported the use of ultrasound for microbial inactivation in other media. Some of the tested microorganisms are Saccharomyces cerevisiae (Guerrero, Tognon, & Alzamora, 2005;Tsukamoto, Constantinoiu, Furuta, Nishimura & Maeda, 2004a;Tsukamoto et al, 2004b;Guerrero, López-Malo, & Alzamora, 2001); Escherichia coli (Ugarte-Romero, Feng, Martin, Cadwallader, & Robinson, 2006;Ananta, Voigt, Zenker, Heinz, & Knorr, 2005;Furuta et al, 2004); L. monocytogenes (Mañas, Pagán, & Raso, 2000;Pagán, Mañas, Alvarez, & Condón, 1999); Salmonella (Cabeza, Ordóñez, Cambero, De la Hoz, & García, 2004); Lactobacillus rhamnosus (Ananta et al, 2005); Yersinia enterocolitica (Raso, Pagán, Condón, & Sala, 1998), among others.…”

Feasibility of Bioenergy Production from Ultrafiltration Whey Permeate Using the UASB Reactors

“…The growth activity of yeast cells is hardly changed within the early period of sonication regardless of either damage to cell wall, or complete inactivation of the yeast located in the cavitation zone (Tsukamoto et al, 2004). Short sonication time up to 5 min of irradiation indicated bactericidal effects, but the cells were able to repair the damages.…”