Polyhydroxyalkanoate production from raisin waste using recombinant Escherichia coli

Since the early 1900s, the rapid proliferation of petroleum-derived polymers has enabled their use in a wide range of applications; however, this widespread utilization has also led to severe environmental problems. As a solution, environmentally friendly alternatives known as bioplastics, produced from biological resources, have been developed. Bioplastics are distinguished by their biodegradability, eco-friendly nature, and biocompatibility. Among them, poly(3-hydroxybutyrate) (P3HB), a member of the polyhydroxyalkanoate (PHA) family, is one of the most widely studied bioplastics. It can be synthesized by various microorganisms and has broad applications in packaging, medicine, pharmaceuticals, agriculture, the automotive industry, hygiene products, and environmental technologies. This thesis aims to produce P3HB using raisin waste as a carbon source with recombinant Escherichia coli Rosetta pQEAL1124. The study includes the optimization of physicochemical parameters affecting the production process and a comparison of conventional and green extraction methods. Response Surface Methodology (RSM) was applied for the optimization of P3HB production, and the optimum conditions providing maximum production were determined as 7.03 g/L raisin waste, 2.46 g/L tryptone, and 194 rpm. Furthermore, the conventional extraction method yielded a maximum of 47% efficiency, while the green extraction method using 1,3-dioxolane resulted in a maximum of P3HB with 33% efficiency.