In general, the key for successful PHAs production via mixed cultures is their enrichment with bacteria that are characterized by high PHAs storage capacity. The enrichment strategies take
place either under alternating anaerobic/aerobic or feast/famine conditions [11].
In addition, the selection of other operational and environmental parameters such as sludge retention time (SRT),pH, organic loading rate (OLR), C/N ratio, temperature etc. play an important role in the enrichment process and the ability of the culture to produce PHAs [6,7,11].