Polyhydroxyalkanoates (PHAs) production from fermented cheese whey by using a mixed microbial culture

Two fermented cheese wheys (FCW), FCW1 composed of lactic, acetic and butyric acids in the proportion of 58/16/26 (% CODOrganic Acid (OA)) and FCW2 composed of acetic, propionic, butyric, lactic and valeric acids in the proportion of 58/19/13/6/4 (% CODOA) were used to produce polyhydroxyalkanoates (PHAs) by using a pre-selected mixed microbial culture (MMC). PHA accumulation gave for fermented FCW1 a PHA yield (Ytot) of 0.24 ± 0.02 mg CODPHA mg CODSoluble Substrate(SS)−1and a total PHA production, referred to the substrate used, of 60 g PHA kgcheese whey Total Solids (TS)−1. For fermented FCW2 results were: PHA yield (Ytot) of 0.42 ± 0.03 mg CODPHA mg CODSS−1and PHA from a substrate of 70 g PHA kgcheese whey TS−1. Qualitatively, PHAs from FCW1 was made up exclusively of 3-hydroxybutyrate (HB), while those obtained from FCW2 were composed of 40% of 3-hydroxyvalerate (HV) and 60% of HB.