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Sporicidal performance induced by photocatalytic production of organic peroxide under visible light irradiation

View Article: PubMed Central - PubMed

ABSTRACT

Bacteria that cause serious food poisoning are known to sporulate under conditions of nutrient and water shortage. The resulting spores have much greater resistance to common sterilization methods, such as heating at 100 °C and exposure to various chemical agents. Because such bacteria cannot be inactivated with typical alcohol disinfectants, peroxyacetic acid (PAA) often is used, but PAA is a harmful agent that can seriously damage human health. Furthermore, concentrated hydrogen peroxide, which is also dangerous, must be used to prepare PAA. Thus, the development of a facile and safe sporicidal disinfectant is strongly required. In this study, we have developed an innovative sporicidal disinfection method that employs the combination of an aqueous ethanol solution, visible light irradiation, and a photocatalyst. We successfully produced a sporicidal disinfectant one hundred times as effective as commercially available PAA, while also resolving the hazards and odor problems associated with PAA. The method presented here can potentially be used as a replacement for the general disinfectants employed in the food and health industries.

No MeSH data available.


Survival rate of B. subtilis spores in the presence of WO3 suspended in ethanol:water solution at the indicated ratios ((a) 0:10; (b) 1:9; (c) 3:7; (d) 6:4; (e) 7:3; (f) 8:2; (g) 9:1, v/v) and illuminated with visible light for the indicated time.Photocatalyst: 25 mg, light source: Xe lamp (vis) with L-42 filter (λ > 420 nm), liquid-phase volume: 50 mL, density of B. subtilis spores: 2.0 × 106 CFU/mL.
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f1: Survival rate of B. subtilis spores in the presence of WO3 suspended in ethanol:water solution at the indicated ratios ((a) 0:10; (b) 1:9; (c) 3:7; (d) 6:4; (e) 7:3; (f) 8:2; (g) 9:1, v/v) and illuminated with visible light for the indicated time.Photocatalyst: 25 mg, light source: Xe lamp (vis) with L-42 filter (λ > 420 nm), liquid-phase volume: 50 mL, density of B. subtilis spores: 2.0 × 106 CFU/mL.

Mentions: We examined the survival rate of B. subtilis spores in the presence of WO3 suspended in aqueous ethanol disinfectant and irradiated with visible light. The dependence of the obtained sporicidal performance on the ethanol:water ratio was studied as shown in Fig. 1. A decrease in the survival rate of B. subtilis spores was first observed for the 6:4 (v/v) ethanol/water solution, with a ca. 2.5-log reduction observed after 24 h of irradiation. At ethanol:water ratios of 7:3, 8:2, and 9:1 (v/v), the spores were completely inactivated after 24, 9, and 12 h visible light irradiation, respectively. Furthermore, we investigated the sporicidal performance of ethanol:water solution at the indicated ratios (3:7, 6:4, 8:2, 9:1, v/v) without WO3. The reduction of survival rate of spore in aqueous ethanol solution was not observed as shown in Supplementary Figure 4.


Sporicidal performance induced by photocatalytic production of organic peroxide under visible light irradiation
Survival rate of B. subtilis spores in the presence of WO3 suspended in ethanol:water solution at the indicated ratios ((a) 0:10; (b) 1:9; (c) 3:7; (d) 6:4; (e) 7:3; (f) 8:2; (g) 9:1, v/v) and illuminated with visible light for the indicated time.Photocatalyst: 25 mg, light source: Xe lamp (vis) with L-42 filter (λ > 420 nm), liquid-phase volume: 50 mL, density of B. subtilis spores: 2.0 × 106 CFU/mL.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036025&req=5

f1: Survival rate of B. subtilis spores in the presence of WO3 suspended in ethanol:water solution at the indicated ratios ((a) 0:10; (b) 1:9; (c) 3:7; (d) 6:4; (e) 7:3; (f) 8:2; (g) 9:1, v/v) and illuminated with visible light for the indicated time.Photocatalyst: 25 mg, light source: Xe lamp (vis) with L-42 filter (λ > 420 nm), liquid-phase volume: 50 mL, density of B. subtilis spores: 2.0 × 106 CFU/mL.
Mentions: We examined the survival rate of B. subtilis spores in the presence of WO3 suspended in aqueous ethanol disinfectant and irradiated with visible light. The dependence of the obtained sporicidal performance on the ethanol:water ratio was studied as shown in Fig. 1. A decrease in the survival rate of B. subtilis spores was first observed for the 6:4 (v/v) ethanol/water solution, with a ca. 2.5-log reduction observed after 24 h of irradiation. At ethanol:water ratios of 7:3, 8:2, and 9:1 (v/v), the spores were completely inactivated after 24, 9, and 12 h visible light irradiation, respectively. Furthermore, we investigated the sporicidal performance of ethanol:water solution at the indicated ratios (3:7, 6:4, 8:2, 9:1, v/v) without WO3. The reduction of survival rate of spore in aqueous ethanol solution was not observed as shown in Supplementary Figure 4.

View Article: PubMed Central - PubMed

ABSTRACT

Bacteria that cause serious food poisoning are known to sporulate under conditions of nutrient and water shortage. The resulting spores have much greater resistance to common sterilization methods, such as heating at 100 °C and exposure to various chemical agents. Because such bacteria cannot be inactivated with typical alcohol disinfectants, peroxyacetic acid (PAA) often is used, but PAA is a harmful agent that can seriously damage human health. Furthermore, concentrated hydrogen peroxide, which is also dangerous, must be used to prepare PAA. Thus, the development of a facile and safe sporicidal disinfectant is strongly required. In this study, we have developed an innovative sporicidal disinfection method that employs the combination of an aqueous ethanol solution, visible light irradiation, and a photocatalyst. We successfully produced a sporicidal disinfectant one hundred times as effective as commercially available PAA, while also resolving the hazards and odor problems associated with PAA. The method presented here can potentially be used as a replacement for the general disinfectants employed in the food and health industries.

No MeSH data available.