title: Isolation of sublineage I Nitrospira by a novel cultivation strategy.
abstract: Nitrification is an important process in the biogeochemical nitrogen cycle and is widely exploited in biological wastewater treatment. Recently, Nitrospira has been recognized as the numerically dominant nitrite-oxidizing bacterial genus and is primarily responsible for the second step of aerobic nitrification. Nevertheless, the physiological properties of Nitrospira remain poorly understood because the organisms are difficult to isolate and culture. Here, we report a novel cultivation strategy for obtaining members of the Nitrospira sublineage I in pure culture. The method combines: (i) selective enrichment of Nitrospira using a continuous feeding reactor and (ii) purification followed by sub-cultivation via a cell sorting system by focusing on the unique characteristics of Nitrospira forming spherical micro-colonies. This strategy is potentially applicable to other uncultured or unisolated Nitrospira and could accelerate the physiological and biochemical understandings of this important group of organisms.
authors.affiliation: Department of Life Science and Medical Bioscience, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Fujitani
authors.forename: Norisuke
authors.initials: N
authors.lastname: Ushiki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tsuneda
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Aoi
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000648:ultrastructure; D001431:Bacteriological Techniques / Q000379:methods; D058465:Nitrification; D010802:Phylogeny