Polyphosphate-accumulating and denitrifying bacteria isolated from anaerobic-anoxic and anaerobic-aerobic sequencing batch reactors

In this study, phosphate-accumulating bacteria achieved complete phosphate removal in two different systems: an anaerobic-anoxic sequencing batch reac tor and an anaerobic-aerobic sequencing batch reactor. This result shows th at phosphate-accumulating bacteria in the Az SBR can use nitrate as termina l electron acceptor instead of oxygen. Phosphate-accumulating bacteria accu mulated phosphate with a rates between 30 and 70 mg P/L/h in the A/O SBR an d between 15 and 32 mg P/L/h in the A(2) SBR. Twenty denitrifying isolates were screened from A2 SBR and nine from A/O SBR. Identification of these is olates by the Biolog system and the API 20 NE identification kit revealed t hat the most active denitrifiers in both SBRs reactors were species of Ochr obactrum, Pseudomonas, Corynebacterium, Agrobacterium, Aquaspirillum, Haemo philus, Xanthomonas, Aeromonas, and Shewanella. The most active phosphate a ccumulating and denitrifying bacteria were identified as Agrobacterium tume faciens B, Aquaspirillum dispar, and Agrobacterium radiobacter. This study showed that the active phosphate accumulating-bacteria were also the most e fficient denitrifying bacteria in both reactors.