Photocatalytic disinfection using titanium dioxide: spectrum and mechanism of antimicrobial activity

• Published in: Applied microbiology and biotechnology Vol. 90; no. 6; pp. 1847 - 1868
• Main Authors: Foster, Howard A., Ditta, Iram B., Varghese, Sajnu, Steele, Alex
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2011; Springer; Springer Nature B.V
• Subjects: Algae; Amoebozoa - drug effects; Analysis; Antimicrobial agents; Bacteria; Bacteria - drug effects; Biological and medical sciences; Biotechnology; Cell Survival - drug effects; Chlorophyta - drug effects; Disinfectants - metabolism; Disinfection; Disinfection & disinfectants; Disinfection - methods; Fundamental and applied biological sciences. Psychology; Fungi - drug effects; Gram-positive bacteria; Hydrogen peroxide; Hydroxyl radicals; Infection control; Life Sciences; Microbial corrosion; Microbial Genetics and Genomics; Microbial Viability - drug effects; Microbiology; Microorganisms; Mineralization; Mini-Review; Organic contaminants; Photocatalysis; Photochemical Processes; Resting stages; Studies; Technology application; Titanium; Titanium - metabolism; Titanium dioxide; Viruses - drug effects; Canada; Antimicrobial; Photocatalysis; ROS; Disinfection; TiO; Titania; Mechanism; Titanium; Antimicrobial agent
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-011-3213-7

The photocatalytic properties of titanium dioxide are well known and have many applications including the removal of organic contaminants and production of self-cleaning glass. There is an increasing interest in the application of the photocatalytic properties of TiO 2 for disinfection of surfaces, air and water. Reviews of the applications of photocatalysis in disinfection (Gamage and Zhang 2010 ; Chong et al., Wat Res 44(10):2997–3027, 2010 ) and of modelling of TiO 2 action have recently been published (Dalrymple et al. , Appl Catal B 98(1–2):27–38, 2010 ). In this review, we give an overview of the effects of photoactivated TiO 2 on microorganisms. The activity has been shown to be capable of killing a wide range of Gram-negative and Gram-positive bacteria, filamentous and unicellular fungi, algae, protozoa, mammalian viruses and bacteriophage. Resting stages, particularly bacterial endospores, fungal spores and protozoan cysts, are generally more resistant than the vegetative forms, possibly due to the increased cell wall thickness. The killing mechanism involves degradation of the cell wall and cytoplasmic membrane due to the production of reactive oxygen species such as hydroxyl radicals and hydrogen peroxide. This initially leads to leakage of cellular contents then cell lysis and may be followed by complete mineralisation of the organism. Killing is most efficient when there is close contact between the organisms and the TiO 2 catalyst. The killing activity is enhanced by the presence of other antimicrobial agents such as Cu and Ag.