Effect of the various carbon sources and growth conditions on phosphate release and uptake by Acinetobacter calcoaceticus

The aim of this study was to investigate the influence of various carbon sources applied at different initial concentrations of phosphorus and growth conditions, on the phosphate re­ lease and uptake in a pure culture of Acinetobacter calcoaceticus DSM1532. P-release and uptake studies with various carbon sources applied at different initial concentrations of phosphorus were carried out in alternating anaerobic/aerobic batch experiments. The best P-release and P-uptake rates were obtained when sodium propionate was the carbon source. Glucose addition in the synthetic wastewater caused lower P-release and uptake ratios, but did not have any significant influence on the final percentage of P-removal. The highest P-release and P-uptake rates were obtained with the highest phosphorus loadings. The highest P-release resulted in the highest P-uptake rates. The observed aerobic P-uptakes in a batch test, without preliminary resort to anaerobic conditions indicate the proba­ ble aerobic mechanism of P-uptake by A. calcoaceticus DSM1532. The results of the semi-continuous test indicate the possibility of the adaptation of A. calcoaceticus DSM1532 to high phosphorus loads (up to 100 mg P L"1) in wastewater.