Microlunatus phosphovorus is a microorganism found inactivated sludge systems. It belongs to the group of polyphosphate-accumulating organisms. Under anaerobic conditions, it utilizes the energy released by the hydrolysis of polyphosphate, for substrate uptake and conversion to internal carbon sources. Under aerobic conditions, however, the previously stored polyhydroxyalcanoate (PHA) is utilized for growth. Because of these properties, M phosphovorus could be used in wastewater treatment plants for biological phosphorus removal.