Abstract
To address the pressing need for sustainable alternatives to conventional plastics, this research developed a route for extracting and purifying polyhydroxyalkanoates (PHAs) using wastewater treatment plant sludge and mixed cultures, thereby promoting a circular economy and reducing sterilisation costs. The methodology began with the design of a fermentation process for selecting producing microorganisms based on a literature review. Three cell lysis reagents were experimentally evaluated 18% SDS, 4% NaOH, and 20% H2SO4, followed by three acetic acid concentrations for extraction and two methanol purification methods (solvent casting and precipitation). Results, analysed via gravimetry, HPLC, and multifactorial ANOVA, determined that lysis and purification are the critical factors in process efficiency. The optimal route consisted of lysis with SDS 10 ml/g, extraction with acetic acid 15 ml/g, and purification with methanol 100 ml/g, achieving a yield of 1.22%, a recovery of 54.61%, and a purity of 19.62%. This study optimises PHAs recovery compared to other methods, establishing a solid foundation for the scalable production of biopolymers capable of replacing traditional synthetic plastics.
Keywords: Polyhydroxyalkanoates, extraction, purification, mixed cultures.
