ACINETOBACTER ISOLATES FROM DIFFERENT ACTIVATED-SLUDGE PROCESSES - CHARACTERISTICS AND NEURAL-NETWORK IDENTIFICATION

Acinetobacter species were isolated from various full-scale activated sludge processes based on their abilities to transform an Acinetobacte r calcoaceticus BD413 trp E27 auxotroph. Approximately half of the Aci netobacter isolates (149 out of 282 isolates) were able to accumulate polyphosphate, and some used P-hydroxybutyrate as a sole carbon and en ergy source. Additionally, most of the Acinetobacter isolates were una ble to reduce nitrate, These characteristics of Acinetobacter species are desirable for microorganisms responsible for enhanced phosphorus r emoval in different activated sludge processes. The backpropagation ne ural network technique was further applied to assign the isolates to d istinct Acinetobacter genospecies based on their phenotypic characteri stics. In particular, Acinetobacter johnsonii was consistently the maj or genospecies from different samples obtained from the enhanced phosp horus removal processes or the conventional plant without biological p hosphorus removal.