Wastewater treatment plants harbour different bacterial populations able to accumulate intracellular polyphosphate (PolyP). Such microorganisms can be enriched to improve phosphate elimination. These PolyP accumulating bacteria are also able to synthetize polyhydroxyalcanoates (PHAs) from glycogen and volatile fatty acids. PHAs are polyesters completely biodegradable that can be used for bioplastic production. Currently, PHAs are produced by selected strains under strict sterile conditions, which induce high production costs. To reduce such PHA productions costs, the use of PHA-producing mixed cultures, obtained from wastewater treatment plants, is considered as a suitable methodology for PHA production under non-sterile conditions (Serafim et al, 2008). In this way, it would be possible to add value to residues such as volatile fatty acids obtained from the anaerobic digestion of organic wastes via PHA production.
In this study, we analyse the microbial community dynamics during PHA production (SSCP fingerprint, 16S rRNA); we also present the dynamics of functional genes (pha synthase) during PHA production in controlled bioreactors working under different conditions (Shamala et al., 2003; Goddon et al., 1997).
Serafim, L.S., Lemos, P.C., Albuquerque,et al. 2008. Strategies for PHA production by mixed cultures and renewable waste materials. Appl Microbiol Biotechnol 81 : 615-628.
Shamala, T.R., Chandrashekar, A., Vijayendra, et al. 2003. Identification of polyhydroxyalkanoate (PHA)-producing Bacillus spp. Using polymerase chain reaction. J Appl Microbiol 94 : 369-374.
Godon, J.J, Zumstein, E., Dabert, P., et al. 1997. Microbial diversity of an anaerobic digestor as determined by small-subunit rDNA sequence analysis. Appl. Environ. Microbiol. 63 :2802-2813.