A photoelectrocatalytic process that disinfects water contaminated with Mycobacterium kansasii and Mycobacterium avium Michelle Fernanda Brugnera a, *, Marcelo Miyata b , Guilherme Julia ˜o Zocolo a , Clarice Queico Fujimura Leite b , Maria Valnice Boldrin Zanoni a a Department of Analytical Chemistry, Institute of Chemistry of Araraquara, UNESP, Rua Francisco Degni, 55 e Bairro Quitandinha, 14800-900 Araraquara, SP, Brazil b Department of Biological Science, Faculty of Pharmaceutical Science of Araraquara, UNESP, Rodovia Araraquara e Jau ´ , Km 01, 14801-902 Araraquara, SP, Brazil article info Article history: Received 2 May 2013 Received in revised form 21 August 2013 Accepted 24 August 2013 Available online 6 September 2013 Keywords: Photoelectrocatalysis Disinfection TiO 2 nanotubes Ag nanoparticles Mycobacteria abstract Nontuberculous mycobacteria are resistant to conventional water treatment; indeed, they have been recovered from a wide variety of environmental sources. Here, we applied the photoelectrocatalytic technique using a Ti/TiO 2 eAg photoanode to inactivate mycobac- teria. For a mycobacteria population of 5  10 8 CFU mL 1 , we achieved 99.9 and 99.8% inactivation of Mycobacterium kansasii and Mycobacterium avium with rate constant of 6.2  10 3 and 4.2  10 3 min 1 , respectively, after 240 min. We compared the proposed method with the photolytic and photocatalytic methods. Using a mycobacteria population of 7.5  10 4 CFU mL 1 , the proposed Ti/TiO 2 eAg photoanode elicited total mycobacteria inactivation within 3 min of treatment; the presence of Ag nanoparticles in the electrode provided 1.5 larger degradation rate constant as compared with the Ti/TiO 2 anode (1.75  10 2 for M. kansassi and 1.98  10 2 for M. avium). We monitored the degradation of the metabolites released during cellular lysis by TOC removal, sugar release, chromatog- raphy, and mass spectrometry measurements; photoelectrocatalysis and Ti/TiO 2 eAg photoanodes furnished the best results. ª 2013 Elsevier Ltd. All rights reserved. 1. Introduction Except for the tubercle bacilli, mycobacteria that cause tuberculosis, there are other mycobacteria usually referred as atypical or nontuberculous mycobacteria (NTM). Most of the NTM are saprophytic, although some are potential pathogens involved in pulmonary or cutaneous diseases as well as lymphadenitis. Infection is thought to occur by ingestion, inhalation, or inoculation. Recently, there has been increasing evidence that water can be the vehicle through which myco- bacteria infect or colonize the human body (Le Dantec et al., 2002). NTM such as Mycobacterium avium and Mycobacterium kansasii have frequently been isolated from drinking water and hospital water distribution systems (Vaerewijck et al., 2005; Vantarakis et al., 1998; Peters et al., 1995). Moreover, concentrations of free residual chlorine equal to or greater than 0.5 mg L 1 in the water supply network are necessary to eliminate environmental mycobacteria (Tsintzou et al., 2000). * Corresponding author. Tel.: þ55 16 3301 9519. E-mail addresses: michellebrugnera@gmail.com, brugnera@iq.unesp.br (M.F. Brugnera). Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate/watres water research 47 (2013) 6596 e6605 0043-1354/$ e see front matter ª 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.watres.2013.08.027