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Influence of outer membrane c-type cytochromes on particle size and activity of extracellular nanoparticles produced by Shewanella oneidensis

Authors

  • Chun Kiat Ng,

    1. Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 639789; telephone: +65-6790-5277; fax: +65-6791-0676
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  • Krishnakumar Sivakumar,

    1. Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 639789; telephone: +65-6790-5277; fax: +65-6791-0676
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  • Xin Liu,

    1. School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 637511
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  • Munusamy Madhaiyan,

    1. Biomaterials and Biocatalyst group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604
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  • Lianghui Ji,

    1. Biomaterials and Biocatalyst group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604
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  • Liang Yang,

    1. Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 639789; telephone: +65-6790-5277; fax: +65-6791-0676
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  • Chuyang Tang,

    1. School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 637511
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  • Hao Song,

    1. Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 639789; telephone: +65-6790-5277; fax: +65-6791-0676
    2. School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637551
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  • Staffan Kjelleberg,

    1. Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 639789; telephone: +65-6790-5277; fax: +65-6791-0676
    2. Centre for Marine Bio-Innovation and School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
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  • Bin Cao

    Corresponding author
    1. Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 639789; telephone: +65-6790-5277; fax: +65-6791-0676
    2. School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 637511
    • Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 639789; telephone: +65-6790-5277; fax: +65-6791-0676
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Abstract

The metal-reducing bacterium Shewanella oneidensis is capable of reducing various metal(loid)s and produces nanoparticles (NPs) extracellularly, in which outer membrane c-type cytochromes (OMCs) have been suggested to play important roles. The objective of this study was to investigate the influence of the OMCs, that is, MtrC and OmcA, on the size and activity of the extracellular silver NPs (AgNPs) and silver sulfide NPs (Ag2S NPs) produced by S. oneidensis MR-1. We found that (i) the lack of OMCs on S. oneidensis cell surface decreased the particle size of the extracellular biogenic AgNPs and Ag2S NPs; (ii) the biogenic AgNPs from the mutant lacking OMCs showed higher antibacterial activity; and (iii) the biogenic Ag2S NPs from the mutant lacking OMCs exhibited higher catalytic activity in methylviologen reduction. The results suggest that it may be possible to control particle size and activity of the extracellular biogenic NPs via controlled expression of the genes encoding surface proteins. In addition, we also reveal that in extracellular biosynthesis of NPs the usually neglected non-cell-associated NPs could have high catalytic activity, highlighting the need of novel methods that can efficiently retain extracellular NPs in the biosynthesis processes. Biotechnol. Bioeng. 2013; 110: 1831–1837. © 2013 Wiley Periodicals, Inc.

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