The anammox activity of a freshwater anammox consortium was strongly inhibited at low-salinity level. Stepwise adaptation from 0 to 3 g NaCl L-1 took 153 days. Further adaptation to high-salinity concentration (from 3 to 30 g L-1) took only 40 days, and no inhibition was observed. A comprehensive insight into the salinity-induced successions of the total and the anammox communities was obtained by 454 pyrosequencing of 16S rRNA gene amplicons and statistical analysis. A major succession in the anammox community was observed at 3 g L-1 where the dominating population shifted from Candidatus Brocadia fulgida to Ca. Kuenenia stuttgartiensis. The latter dominated at high salinity and seemed to be essential for the high (˃96%) ammonium and nitrite removal efficiencies achieved. SIMPER analysis indicated that these two dominating anammox species explained most to the differences in community structure among samples and helped in identifying other important members at different salinities.
Keywords: Amplicon pyrosequencing; Anammox; Bacterial community; Salinity.