Chemical digestion method to promote activated sludge cell wall breaking and optimize the polyhydroxyalkanoate (PHA) extraction process.

A novel protocol for the recovery of PHA from mixed-cultures proposed. In this experiment, activated sludge for PHA synthesis was investigated and a two-stage chemical digestion method was used for activated sludge to improve the yield of PHA. The highest PHA extraction combination that could be obtained in this experiment was sodium hypochlorite(NaClO) plus sodium dodecyl sulfate (SDS), and the optimal concentration of NaClO solution was 25 % (v/v), and the ratio of the dry weight of activated sludge to SDS was 1:2. The recovery and purity of PHA were 72.14 % and 54.47 %, respectively. The reaction time between NaClO and activated sludge affects the recovery of PHA, and the optimal reaction time of NaClO was experimentally obtained as 30 min. The purity of the PHA extract obtained after purification using methanol was improved.