The inactivation and removal of airborne Bacillus atrophaeus endospores from air circulation systems using UVC and HEPA filters
Open Access
- 10 October 2007
- journal article
- Published by Oxford University Press (OUP) in Journal of Applied Microbiology
- Vol. 104 (2), 489-498
- https://doi.org/10.1111/j.1365-2672.2007.03569.x
Abstract
To (i) evaluate the UV radiation in the 'C' band/high efficient particulate air (UVC/HEPA) instrument's potential to inactivate spores of Bacillus atrophaeus and selected Bacillus species and (ii) test whether a titanium dioxide coating inside the cylindrical HEPA filter improves the system's efficacy. Known amounts of dried spore preparations of B. atrophaeus, Bacillus cereus, Bacillus megaterium, Bacillus stearothermophilus and Bacillus thuringiensis were exposed to the UVC lamp within a cylindrical HEPA filter for different time lengths (30 min to 48 h) and with different air flow speeds (0-235 l s(-1)). The log(10) reduction (range 5-16 logs) of colony forming units for spores exposed to the UVC compared with the unexposed spores was significant (P < 0.0001). The addition of a titanium dioxide (TiO(2)) veneer to the interior surface of the HEPA filter significantly increased the inactivation of spores (P < 0.0001). The UVC/HEPA unit could inactivate spores of B. atrophaeus, B. cereus, B. megaterium, B. stearothermophilus and B. thuringiensis. The UVC/HEPA unit represents an effective method of decontaminating circulating air within an air-duct system as found in a building.Keywords
This publication has 20 references indexed in Scilit:
- Virulent spores of Bacillus anthracis and other Bacillus species deposited on solid surfaces have similar sensitivity to chemical decontaminantsJournal of Applied Microbiology, 2006
- Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV IrradiationApplied and Environmental Microbiology, 2005
- Inactivation of Bacillus Spores by Ultraviolet or Gamma RadiationJournal of Environmental Engineering, 2005
- Solar and photocatalytic disinfection of protozoan, fungal and bacterial microbes in drinking waterWater Research, 2005
- Role of pigmentation in protecting Bacillus sp. endospores against environmental UV radiationFEMS Microbiology Ecology, 2005
- Ultraviolet and ionizing radiation for microorganism inactivationWater Research, 2004
- Continuous-flow UVC irradiation: a new, effective, protein activity-preserving system for inactivating bacteria and viruses, including erythrovirus B19Journal of Virological Methods, 2004
- Disinfection of surfaces by photocatalytic oxidation with titanium dioxide and UVA lightChemosphere, 2003
- UV Resistance of Bacillus anthracis Spores Revisited: Validation of Bacillus subtilis Spores as UV Surrogates for Spores of B. anthracis SterneApplied and Environmental Microbiology, 2003
- Air-cleaning System Effectiveness for Control of Airborne Microbes in a Meat-processing PlantJournal of Food Science, 2002