title: Cultivation of planktonic anaerobic ammonium oxidation (anammox) bacteria using membrane bioreactor.
abstract: Enrichment cultures of anaerobic ammonium oxidation (anammox) bacteria as planktonic cell suspensions are essential for studying their ecophysiology and biochemistry, while their cultivation is still laborious. The present study aimed to cultivate two phylogenetically distinct anammox bacteria, "Candidatus Brocadia sinica" and "Ca. Scalindua sp." in the form of planktonic cells using membrane bioreactors (MBRs). The MBRs were continuously operated for more than 250 d with nitrogen loading rates of 0.48-1.02 and 0.004-0.09 kgN m(-3) d(-1) for "Ca. Brocadia sinica" and "Ca. Scalindua sp.", respectively. Planktonic anammox bacterial cells were successfully enriched (>90%) in the MBRs, which was confirmed by fluorescence in-situ hybridization and 16S rRNA gene sequencing analysis. The decay rate and half-saturation constant for NO2(-) of "Ca. Brocadia sinica" were determined to be 0.0029-0.0081 d(-1) and 0.47 mgN L(-1), respectively, using enriched planktonic cells. The present study demonstrated that MBR enables the culture of planktonic anammox bacterial cells, which are suitable for studying their ecophysiology and biochemistry.
authors.affiliation: Division of Environmental Engineering, Faculty of Engineering, Hokkaido University.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Oshiki
authors.forename: Takanori
authors.initials: T
authors.lastname: Awata
authors.forename: Tomonori
authors.initials: T
authors.lastname: Kindaichi
authors.forename: Hisashi
authors.initials: H
authors.lastname: Satoh
authors.forename: Satoshi
authors.initials: S
authors.lastname: Okabe
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism*; D000693:Anaerobiosis; D001419:Bacteria / Q000254:growth & development* / Q000378:metabolism; D061249:Batch Cell Culture Techniques / Q000295:instrumentation / Q000379:methods*; D019149:Bioreactors / Q000382:microbiology*; D010084:Oxidation-Reduction; D010933:Plankton / Q000254:growth & development* / Q000378:metabolism
chemical_list: D064751:Ammonium Compounds