Extraction of polyhydroxyalkanoates from mixed microbial cultures: Impact on polymer quality and recovery

Chiara Samorì, Federica Abbondanzi, Paola Galletti, Loris Giorgini, Laura Mazzocchetti, Cristian Torri, Emilio Tagliavini

Centro Interdipartimentale di Ricerca Industriale Energia Ambiente (CIRI EA), University of Bologna, via S. Alberto 163, 48123 Ravenna, Italy.

Abstract

Polyhydroxyalkanoates (PHAs) can be extracted from mixed microbial cultures (MMCs) by means of dimethyl carbonate (DMC) or combination of DMC and sodium hypochlorite (NaClO). The protocol based on DMC, a green solvent never used before for the extraction of PHAs from MMC, allows an overall polymer recovery of 63%; also the purity and the molecular weight of the recovered polymers are good (98% and 1.2 MDa, respectively). The use of NaClO pretreatment before DMC extraction increases the overall PHA recovery (82%) but lowers the mean molecular weight to 0.6–0.2 MDa. A double extraction with DMC results to be the method of choice for the recovery of high quality PHAs from attractive but challenging MMCs.

Keywords: Mixed microbial cultures; Polyhydroxyalkanoates; Polymer extraction; Dimethyl carbonate.