Sustainable Development of Antimicrobial Polyvinyl Chloride Bioplastics Using Chlamydomonas reinhardtii Extract

The green microalga Chlamydomonas reinhardtii was utilized for bio-based plastic production, focusing on optimizing polyhydroxybutyrate (PHB) synthesis. Optimal cultivation conditions (40 °C, pH 8.8, light intensity 1100 lux, salinity 0.15 M) yielded 102.84 ± 0.5 mg/g of PHB, while phosphorus-free media with 2 g/L sodium acetate achieved a maximum of 201 ± 0.5 mg/g. Bioplastic films were developed by blending polyvinyl chloride (PVC) with C. reinhardtii extracts (0-75%). The 50% algal extract/PVC blend exhibited the best mechanical properties, with a tensile stress of 9.41 MPa and 2% elongation. Chloroform extracts of C. reinhardtii showed significant antimicrobial activity against bacteria and fungi, with the highest inhibition (31 ± 0.28 mm) against Staphylococcus aureus. This study highlights the potential of C. reinhardtii-based biodegradable antimicrobial bioplastics as eco-friendly alternatives to conventional plastics.