Uptake and release of phosphate by a pure culture of Acinetobacter calcoaceticus

Uptake and release of phosphate by a pure culture of Acinetobacter calcoaceticus were investigated under aerobic and anaerobic conditions. The total phosphorus content of this bacterium varied from 0.3 to 1.7 mmol g⁻¹ dry cells or from 0.93 to 5.3% of dry cell weight under various culture conditions. The log-phase cells accumulated polyphosphates of 0.33−0.64 mmol P g⁻¹ dry cells. ³¹P NMR spectra suggested that a portion of polyphosphates was likely bonded to some sort of structural components of the cell. A. calcoaceticus release phosphate linearly with time when transferred from aerobic to anaerobic conditions. The release rate was in the range of 5.9–14.7 × 10⁻³ mmol P g⁻¹ dry cells h⁻¹ and about 4–8% of cellular phosphorus was released during the initial 6 h. During the process of phosphate release acetate was not taken up by this bacterium.