Open AccessEffects of ammonium and nitrite on communities and populations of ammonia‐oxidizing bacteria in laboratory‐scale continuous‐flow reactors
Author(s) -
Limpiyakorn Tawan,
Kurisu Futoshi,
Sakamoto Yoriko,
Yagi Osami
Publication year - 2007
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2007.00307.x
Subject(s) - nitrosomonas , nitrite , ammonium , nitrosomonas europaea , biology , nitrification , activated sludge , ammonia , anammox , nitrobacter , temperature gradient gel electrophoresis , environmental chemistry , microbiology and biotechnology , bacteria , 16s ribosomal rna , food science , nuclear chemistry , biochemistry , sewage treatment , chemistry , denitrification , ecology , environmental engineering , nitrate , nitrogen , denitrifying bacteria , organic chemistry , engineering , genetics
This study investigated the effects of ammonium and nitrite on ammonia‐oxidizing bacteria (AOB) from an activated sludge process in laboratory‐scale continuous‐flow reactors. AOB communities were analyzed using specific PCR followed by denaturing gel gradient electrophoresis, cloning and sequencing of the 16S rRNA gene, and AOB populations were quantified using real‐time PCR. To study the effect of ammonium, activated sludge from a sewage treatment system was enriched in four reactors receiving inorganic medium containing four different ammonium concentrations (2, 5, 10 and 30 mM NH 4 + ‐N). One of several sequence types of the Nitrosomonas oligotropha cluster predominated in the reactors with lower ammonium loads (2, 5 and 10 mM NH 4 + ‐N), whereas Nitrosomonas europaea was the dominant AOB in the reactor with the highest ammonium load (30 mM NH 4 + ‐N). The effect of nitrite was studied by enriching the enriched culture possessing both N. oligotropha and N. europaea in four reactors receiving 10‐mM‐ammonium inorganic medium containing four different nitrite concentrations (0, 2, 12 and 22 mM NO 2 − ‐N). Nitrosomonas oligotropha comprised the majority of AOB populations in the reactors without nitrite accumulation (0 and 2 mM NO 2 − ‐N), whereas N. europaea was in the majority in the 12‐ and 22‐mM NO 2 − ‐N reactors, in which nitrite concentrations were 2.1–5.7 mM (30–80 mg N L −1 ).