PHOSPHATE RELEASE AND UPTAKE BY PURE CULTURES OF ACINETOBACTER SP - EFFECT OF THE VOLATILE FATTY-ACIDS CONCENTRATION

Phosphorus release and uptake by pure cultures of Acinetobacter strain s were investigated under anaerobic and aerobic conditions respectivel y. Tests were performed to study the relationship between phosphorus r elease-storage reaction and behavior of extracellular organic substrat es: acetic, propionic, and butyric acids have been used at four concen trations (50, 100, 500, and 1000 mg . L(-1)) in the anaerobic step of biological phosphorus removal. The results obtained depend on the stra in and the volatile fatty acid (VFA) used. Phosphorus released under a naerobic condition was not always related to the amount of VFA or phos phorus consumed. Phosphorus uptake (P-uptake) in the aerobic step was found to be independent of phosphorus release rates. The best phosphor us uptake rates were obtained by Acinetobacter lwoffi ATCC21130 and Ac inetobacter calcoaceticus Genoespecie SUCT-5 with butyric acid as carb on source.