Affiliations: Department of Biology, Liaoning Normal University,
Dalian 116021, China | Institute of Applied Ecology, Chinese Academy of
Sciences, Shenyang 110016, China | Faculty of Life Science and Biotechnology, Ningbo
University, Ningbo 315211
Abstract: OLAND (oxygen limited autotrophic nitrification and denitrification)
nitrogen removal system was constructed by coupling with oxygen limited
nitritation stage and anaerobic ammonium oxidation stage. Ammonia oxidizer, as
a kind of key bacteria in N cycle, plays an important role at the oxygen
limited nitritation stage of OLAND nitrogen removal system. In this study,
specific amplification of 16S rDNA fragment of ammonia oxidizer by nested PCR,
separation of mixed PCR samples by denaturing gradient gel electrophoresis
(DGGE), and the quantification of ammonia oxidizer by Fluorescence in situ
hybridization (FISH) were combined to investigate the shifts of community
composition and quantity of ammonia oxidizer of the oxygen limited nitritation
stage in OLAND system. It showed that the community composition of ammonia
oxidizer changed drastically when dissolved oxygen was decreased gradually, and
the dominant ammonia oxidizer of the steady nitrite accumulation stage were
completely different from that of the early stage of oxygen limited nitritation
identified by DGGE. It was concluded that the Nitrosomonas may be the dominant
genus of ammonia oxidizer at the oxygen limited nitritation stage of OLAND
system characterized by nested PCR-DGGE and FISH, and the percentage of
Nitrosomonas was 72.5% ± 0.8% of ammonia oxidizer at the steady nitrite
accumulation stage detected by FISH.
Keywords: OLAND, nitritation, ammonia oxidizer, DGGE, FISH
