The membrane bioreactor: A novel tool to grow anammox bacteria as free cells

Authors

  • Wouter R.L. van der Star,

    1. Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628BC Delft, The Netherlands; telephone: +31-15-2781618; fax: +31-15-2782355
    Current affiliation:
    1. Deltares, P.O. Box 177, 2600 MH Delft, The Netherlands.
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  • Andreea I. Miclea,

    1. Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628BC Delft, The Netherlands; telephone: +31-15-2781618; fax: +31-15-2782355
    2. Department of Experimental Biology, Faculty of Biology and Geology, Babeş-Bolyai University, Clinicolor Street 5-7, Cluj-Napoca, Romania
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  • Udo G.J.M. van Dongen,

    1. Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628BC Delft, The Netherlands; telephone: +31-15-2781618; fax: +31-15-2782355
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  • Gerard Muyzer,

    1. Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628BC Delft, The Netherlands; telephone: +31-15-2781618; fax: +31-15-2782355
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  • Cristian Picioreanu,

    1. Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628BC Delft, The Netherlands; telephone: +31-15-2781618; fax: +31-15-2782355
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  • Mark C.M. van Loosdrecht

    Corresponding author
    1. Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628BC Delft, The Netherlands; telephone: +31-15-2781618; fax: +31-15-2782355
    • Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628BC Delft, The Netherlands; telephone: +31-15-2781618; fax: +31-15-2782355.
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Abstract

In a membrane bioreactor (MBR), fast growth of anammox bacteria was achieved with a sludge residence time (SRT) of 12 days. This relatively short SRT resulted in a—for anammox bacteria—unprecedented purity of the enrichment of 97.6%. The absence of a selective pressure for settling, and dedicated cultivation conditions led to growth in suspension as free cells and the complete absence of flocs or granules. Fast growth, low levels of calcium and magnesium, and possibly the presence of yeast extract and a low shear stress are critical for the obtainment of a completely suspended culture consisting of free anammox cells. During cultivation, a population shift was observed from Candidatus “Brocadia” to Candidatus “Kuenenia stuttgartiensis.” It is hypothesized that the reason for this shift is the higher affinity for nitrite of “Kuenenia.” The production of anammox bacteria in suspension with high purity and productivity makes the MBR a promising tool for the cultivation and study of anammox bacteria. Biotechnol. Bioeng. 2008;101: 286–294. © 2008 Wiley Periodicals, Inc.

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