Enhanced photocatalytic inactivation of bacterial spores on surfaces in air

  • Amit Vohra
  • D. Y. Goswami
  • D. A. Deshpande
  • S. S. Block
Original Paper


TiO2 photocatalysis with ultraviolet (UV-A) light has proven to be a highly effective process for complete inactivation of airborne microbes. However, the overall efficiency of the technology needs to be improved to make it more attractive as a defense against bio-terrorism. The present research investigates the enhancement in the rate of destruction of bacterial spores on metal (aluminum) and fabric (polyester) substrates with metal (silver)-doped titanium dioxide and compares it to conventional photocatalysis (TiO2 P25/+UV-A) and UV-A photolysis. Bacillus cereus bacterial spores were used as an index to demonstrate the enhanced disinfection efficiency. The results indicate complete inactivation of B. cereus spores with the enhanced photocatalyst. The enhanced spore destruction rate may be attributed to the highly oxidizing radicals generated by the doped TiO2.


Photocatalysis Metal-doped TiO2 Silver Bacillus cereus spores Fabric UV-A 


  1. 1.
    Arabatzis IM, Stergiopoulos T, Bernard MC, Labou D, Neophytides SG, Falaras P (2003) Silver-modified titanium dioxide thin films for efficient photodegradation of methyl orange. Appl Catal B Environ 42:187–201CrossRefGoogle Scholar
  2. 2.
    Atrih A, Foster SJ (2002) Bacterial endospores the ultimate survivors. Int Dairy J 12:217–223CrossRefGoogle Scholar
  3. 3.
    Beaudreau C, Hingorani SK, Goswami TK, Goswami DY (1998) Destruction of dust mite allergens using PhotechTM – photocatalytic technology for disinfection of indoor air. In: presented at Pan-American Workshop on Commercialization of Advanced Oxidation Technologies, Ontario, CanadaGoogle Scholar
  4. 4.
    Blake DM, Maness P, Huang Z, Wolfrum EJ, Huang J, Jacoby WA (1999) Application of the photocatalytic chemistry of titanium dioxide to disinfection and the killing of cancer cells. Sep Purif Methods 28(1):1–50CrossRefGoogle Scholar
  5. 5.
    Block SS (1991) Disinfection, sterilization, and preservation. Lea and Febiger, PhiladelphiaGoogle Scholar
  6. 6.
    Chen J, Ollis DF, Rulkens WH, Bruning H (1999) Photocatalyzed oxidation of alcohols and organochlorides in the presence of native TiO2 and metallized TiO2 suspensions. Part (I): photocatalytic activity and pH influence. Water Res 33:661–668CrossRefGoogle Scholar
  7. 7.
    Davydov L, Smirtiotis PG (2000) Quantification of the primary processes in aqueous heterogeneous photocatalysis using single-stage oxidation reactions. J Catal 191:105–116CrossRefGoogle Scholar
  8. 8.
    Dhananjeyan MR, Kandavelu V, Renganathan R (2000) A study on the photocatalytic reactions of TiO2 with certain pyrimidine bases: effects of dopants (Fe3+) and calcination. J Mol Catal A Chem 151:217–223CrossRefGoogle Scholar
  9. 9.
    Dvoranova D, Brezova V, Mazur M, Malati MA (2002) Investigation of metal-doped titanium dioxide photocatalysis. Appl Catal B Environ 37:91–105CrossRefGoogle Scholar
  10. 10.
    Fujishima A, Rao TN, Tryk DA (2000) Titanium dioxide photocatalysis. J Photochem Photobiol C Photochem Rev 1:1–21CrossRefGoogle Scholar
  11. 11.
    Gerischer H (1970) In: Eyring H, Henderson D, Jost W (eds) Physical chemistry – an advanced treatise. Academic, New York, pp 465–542Google Scholar
  12. 12.
    Goswami DY (1999) Recent developments in photocatalytic detoxification and disinfection of water and air. In: proceedings of the ISES 1999 Solar World Congress, Jerusalem, IsraelGoogle Scholar
  13. 13.
    Goswami DY, Trivedi D, Block SS (1995) Photocatalytic disinfection of indoor air. Solar engineering, In: proceedings of the ASME International Solar Energy Conference, Hawaii, pp 421–430Google Scholar
  14. 14.
    Goswami DY, Trivedi D, Block SS (1997) Photocatalytic disinfection of indoor air. J Solar Energy Eng 119:92–96Google Scholar
  15. 15.
    Greist HT, Hingorani SK, Kelly K, Goswami DY (2002) Using scanning electron microscopy to visualize photocatalytic mineralization of airborne microorganisms. In: proceedings of the Indoor Air 2002, 9th International Conference on Indoor Air Quality and Climate, Monterey, California, pp 712–717Google Scholar
  16. 16.
    Hoffmann MR, Martin ST, Choi W, Bahnemann DW (1995) Environmental applications of heterogeneous photocatalysis. Chem Rev 95:69CrossRefGoogle Scholar
  17. 17.
    Jacoby WA, Maness PC, Wolfrum EJ, Blake DM, Fennell JA (1998) Mineralization of bacterial cell mass on a photocatalytic surface in air. Environ Sci Technol 32:2650–2653CrossRefGoogle Scholar
  18. 18.
    Kennedy III JC, Datye AK (1998) Photothermal heterogeneous oxidation of ethanol over Pt/TiO2. J Catal, 179:375–389CrossRefGoogle Scholar
  19. 19.
    Kim B, Kim D, Cho D, Cho S (2003) Bactericidal effect of TiO2 photocatalyst on food-borne pathogenic bacteria. Chemosphere 52:277–281CrossRefPubMedGoogle Scholar
  20. 20.
    Knight H (2003) Sars wars. Engineer 292:27–35Google Scholar
  21. 21.
    Kuhn KP, Chaberny IF, Massholder K, Stickler M, Benz VW, Sonntag H, Erdinger L (2003) Disinfection of surfaces by photocatalytic oxidation with titanium dioxide and UV-A light. Chemosphere 53:71–77CrossRefPubMedGoogle Scholar
  22. 22.
    Lawton LA, Robertson PKJ, Cornish BJPA, Marr IL, Jaspers M (2003) Processes influencing surface interaction and photocatalytic destruction of microcystins on titanium dioxide photocatalysis. J Catal 213:109–113CrossRefGoogle Scholar
  23. 23.
    Lee W, Shen H-S, Dwight K, Wold A (1993) Effect of Silver on the Photocatalytic activity of TiO2. J Solid State Chem 106:288–294CrossRefGoogle Scholar
  24. 24.
    Litter MI, Navio JA (1996) Photocatalytic properties of iron-doped titania semiconductors. J Photochem Photobiol A Chem 98:171–181CrossRefGoogle Scholar
  25. 25.
    Liu Y, Liu C-Y, Rong Q-H, Zhang Z (2003) Chanracteristics of the silver-doped TiO2 nanoparticles. Appl Surf Sci 220:7–11CrossRefGoogle Scholar
  26. 26.
    Masaki Y, Masaude S, Ishida K (1999) TiO2 photocatalyst for environmental purification. Sumitomo Met 50:26–32Google Scholar
  27. 27.
    Matsunaga T, Tamoda R, Nakajima T, Wake H (1985) Photoelectrochemical sterilization of microbial cells by semiconductor powders. FEMS Microbiol Lett 29:211–214CrossRefGoogle Scholar
  28. 28.
    Mills A, Le Hunte S (1997) An overview of semiconductor photocatalysis. J Photochem Photobiol A Chem 108:1–35CrossRefGoogle Scholar
  29. 29.
    Minero C (1999) Kinetic analysis of photoinduced reactions at the water semiconductor interface. Catal Today 54:205–216CrossRefGoogle Scholar
  30. 30.
    Moeller R, Horneck G, Facius R, Stackebrandt E (2005) Role of pigmentation in protecting Bacillus sp. endospores against environmental UV radiation. FEMS Microbiol Ecol 51:231–236CrossRefGoogle Scholar
  31. 31.
    Riesenman PJ, Nicholson WL (2000) Role of the spore coat layers in Bacillus subtillis spore resistance to hydrogen peroxide, artificial UV-C, UV-B, and solar UV radiation. Appl Environ Microbiol 66:620–626CrossRefGoogle Scholar
  32. 32.
    Rincon A-G, Pulgarin C (2005) Use of coaxial photocatalytic reactor (CAPHORE) in the TiO2 photo-assisted treatment of mixed E. coli and Bacillus sp. And bacterial community present in wastewater. Catal Today 101:331–344CrossRefGoogle Scholar
  33. 33.
    Shephard GS, Stockenstrom S, de Villiers D, Engelbrecht WJ, Wessels GFS (2002) Degradation of microcystin toxins in a falling film photocatalytic reactor with immobilized titanium dioxide catalyst. Water Res 36:140–146CrossRefPubMedGoogle Scholar
  34. 34.
    Sokmen M, Candan F, Sumer Z (2001) Disinfection of E. coli by the Ag-TiO2/UV system: lipidperoxidation. J Photochem Photobiol A Chem 143:241–244CrossRefGoogle Scholar
  35. 35.
    Turchi CS, Ollis DF (1990) Photocatalytic degradation of organic water contaminants; mechanisms involving hydroxyl radical attack. J Catal 122:178CrossRefGoogle Scholar
  36. 36.
    Wang Y, Cheng H, Zhang L, Hao Y, Ma J, Xu B, Li W (2000) The preparation, characterization, photoelectrochemical and photocatalytic properties of lanthanide metal-ion-doped TiO2 nanoparticles. J Mol Catal A Chem 151:205–216CrossRefGoogle Scholar
  37. 37.
    Wolfrum EJ, Huang J, Blake DM, Maness P, Huang Z, Fiest J (2002) Photocatalytic oxidation of bacteria, bacterial and fungal spores, and model biofilm components to carbon dioxide on titanium dioxide-coated surfaces. Environ Sci Technol 36:3412–3419CrossRefGoogle Scholar

Copyright information

© Society for Industrial Microbiology 2005

Authors and Affiliations

  • Amit Vohra
    • 1
  • D. Y. Goswami
    • 1
  • D. A. Deshpande
    • 1
  • S. S. Block
    • 1
  1. 1.Solar Energy and Energy Conversion Laboratory, Department of Mechanical and Aerospace EngineeringUniversity of FloridaGainesvilleUSA

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