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 Acinetobacter calcoaceticus BD413 trp E27 auxotroph. Approximately half of the Acinetobacter isolates (149 out of 282 isolates) were able to accumulate polyphosphate, and some used P-hydroxybutyrate as a sole carbon and energy source. Additionally, most of the Acinetobacter isolates were unable to reduce nitrate, These characteristics of Acinetobacter species are desirable for microorganisms responsible for enhanced phosphorus removal in different activated sludge processes. The backpropagation neural network technique was further applied to assign the isolates to distinct Acinetobacter genospecies based on their phenotypic characteristics. In particular, Acinetobacter johnsonii was consistently the major genospecies from different samples obtained from the enhanced phosphorus removal processes or the conventional plant without biological phosphorus removal.