Selective enrichment and molecular characterization of a previously uncultured Nitrospira-like bacterium from activated sludge.
Previously uncultured nitrite-oxidizing bacteria affiliated to the genus Nitrospira have for the first time been successfully enriched from activated sludge from a municipal wastewater treatment plant. During the enrichment procedure, the abundance of the Nitrospira-like bacteria increased to approximately 86% of the total bacterial population. This high degree of purification was achieved by a novel enrichment protocol, which exploits physiological features of Nitrospira-like bacteria and includes the selective repression of coexisting Nitrobacter cells and heterotrophic contaminants by application of ampicillin in a final concentration of 50 microg ml(-1). The enrichment process was monitored by electron microscopy, fluorescence in situ hybridization (FISH) with rRNA-targeted probes and fatty acid profiling. Phylogenetic analysis of 16S rRNA gene sequences revealed that the enriched bacteria represent a novel Nitrospira species closely related to uncultured Nitrospira-like bacteria previously found in wastewater treatment plants and nitrifying bioreactors. The enriched strain is provisionally classified as 'Candidatus Nitrospira defluvii'.
Universität Hamburg, Biozentrum Klein Flottbek, Mikrobiologie, Ohnhorststr. 18, D-22609 Hamburg, Germany. spieck@mikrobiologie.uni-hamburg.de
Eva
E
Spieck
Christine
C
Hartwig
Iris
I
McCormack
Frank
F
Maixner
Michael
M
Wagner
André
A
Lipski
Holger
H
Daims
D000667:Ampicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D018407:Bacterial Physiological Phenomena; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005227:Fatty Acids / Q000032:analysis / Q000737:chemistry; D020459:Genes, rRNA; D017404:In Situ Hybridization, Fluorescence; D008854:Microscopy, Electron; D009576:Nitrobacter / Q000187:drug effects; D012329:RNA, Bacterial / Q000032:analysis; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*; D014871:Water Microbiology
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005227:Fatty Acids; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D000667:Ampicillin