Metabolism of micro-organisms responsible for enhanced biological phosphorus removal from wastewater. Use of dynamic enrichment cultures.

The removal of phosphorus from wastewater is already widely applied. In many cases use is made of micro organisms capable of accumulating phosphorus as polyphosphate inside the cell. The main characteristic providing the competitive advantage to these polyphosphate accumulating bacteria is the capability to use polyphosphate, in the absence of external electron acceptors, as energy source for the uptake and storage of acetic acid in the form of polyhydroxybutyrate (PHB). The reduction equivalents for the formation of PHB are derived from the conversion of glycogen to PHB. Despite the widespread use and study of enhanced biological phosphorus removal no pure culture, having the above mentioned characteristics, has been isolated yet. All ecophysiological studies on these type of cultures have therefore been performed by enrichment cultures. This paper reviews the research on these type of organisms, and shows that it is possible to understand a complex microbial process on a metabolic level, both stoichiometrically and kinetically, without the availability of a pure culture.