The combined fermentation of sludge from the secondary sedimentation tank of municipal wastewatertreatment plants and food waste enables not only waste reduction, but also the acquisition of volatilefatty acids (VFAs) for the biosynthesis of polyhydroxyalkanoates (PHAs). To better understand variablesinfluencing the production of VFAs and PHAs, this study considered anaerobic fermentation of VFAsunder different pH conditions. The production of VFA was the highest at an initial pH of 9.0, reaching25,934 ± 1,485 mg COD/L and a VFAs/SCOD ratio of 0.61 ± 0.04. When the fermentation liquid was used
as a carbon source for PHA biosynthesis, continuous pulsed feeding resulted in the highest PHA synthesisrate of 64.5 ± 1.8%, while the culture receiving a one-time feeding had the lowest rate of only 51.5 ± 2.0%.