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dc.contributor.authorHuang, Guocheng
dc.contributor.authorXia, Dehua
dc.contributor.authorAn, Taicheng
dc.contributor.authorNg, Tsz Wai
dc.contributor.authorYip, Ho Yin
dc.contributor.authorLi, Guiying
dc.contributor.authorZhao, Huijun
dc.contributor.authorWong, Po Keung
dc.date.accessioned2017-08-28T03:08:24Z
dc.date.available2017-08-28T03:08:24Z
dc.date.issued2015
dc.identifier.issn0099-2240
dc.identifier.doi10.1128/AEM.00775-15
dc.identifier.urihttp://hdl.handle.net/10072/125021
dc.description.abstractThe dual roles of capsular extracellular polymeric substances (EPS) in the photocatalytic inactivation of bacteria were demonstrated in a TiO2-UVA system, by comparing wild-type Escherichia coli strain BW25113 and isogenic mutants with upregulated and downregulated production of capsular EPS. In a partition system in which direct contact between bacterial cells and TiO2 particles was inhibited, an increase in the amount of EPS was associated with increased bacterial resistance to photocatalytic inactivation. In contrast, when bacterial cells were in direct contact with TiO2 particles, an increase in the amount of capsular EPS decreased cell viability during photocatalytic treatment. Taken together, these results suggest that although capsular EPS can protect bacterial cells by consuming photogenerated reactive species, it also facilitates photocatalytic inactivation of bacteria by promoting the adhesion of TiO2 particles to the cell surface. Fluorescence microscopy and scanning electron microscopy analyses further confirmed that high capsular EPS density led to more TiO2 particles attaching to cells and forming bacterium-TiO2 aggregates. Calculations of interaction energy, represented by extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) potential, suggested that the presence of capsular EPS enhances the attachment of TiO2 particles to bacterial cells via acid-base interactions. Consideration of these mechanisms is critical for understanding bacterium-nanoparticle interactions and the photocatalytic inactivation of bacteria.
dc.description.peerreviewedYes
dc.languageEnglish
dc.publisherAmerican Society for Microbiology
dc.relation.ispartofpagefrom5174
dc.relation.ispartofpageto5183
dc.relation.ispartofissue15
dc.relation.ispartofjournalApplied and Environmental Microbiology
dc.relation.ispartofvolume81
dc.subject.fieldofresearchMicrobiology not elsewhere classified
dc.subject.fieldofresearchcode060599
dc.titleDual roles of capsular extracellular polymeric substances in photocatalytic inactivation of Escherichia coli: Comparison of E. coli BW25113 and isogenic mutants
dc.typeJournal article
dc.type.descriptionC1 - Articles
dc.type.codeC - Journal Articles
dc.description.versionPublished
gro.rights.copyright© 2015 American Society for Microbiology. The attached file is reproduced here in accordance with the copyright policy of the publisher. Please refer to the journal's website for access to the definitive, published version.
gro.hasfulltextFull Text
gro.griffith.authorZhao, Huijun


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