Exploration of Polyhydroxybutyrate (PHB) Production Potential of Photosynthetic Microbes: A Sustainable Source of Bioplastic

The present study examined Polyhydroxy butyrate production (PHB) potential of different photosynthetic microbes such as Chlorella vulgaris, Scenedesmus obliquus and Rhodobacter capsulatus-PK under different nutrient conditions. Biodegradable bioplastics, such as Poly-β-hydroxybutyrates (PHB), derived from these microbes provide a sustainable alternative to conventional petroleum-based nondegradable plastics. As the demand for clean and sustainable alternatives rises, bio-plastic is gaining attention as a viable substitute to conventional plastics. However, conventional sources of bio-plastic production have inherent limitations, which can be effectively addressed through the utilization of photosynthetic microbes e.g. microalgae, purple non sulphur bacteria. The production of bioplastic was evaluated by cultivating the microalgae in BG-11, BBM and PNSB in synthetic growth media (MI, MII) with different nitrogen concentrations of 0%, 50% and 100%. The biopolymer (PHB) was obtained from all experiments in a wide range of concentration (7-42.8%) of dry cell weight (DCW). In this study, algal isolate SK1 demonstrated the highest PHB content (42.8%) in BBM under 100% nitrogen starvations rendering the bioplastic exceptionally compatible and suitable for eco-friendly applications. Additionally, various patents cited by different authors on different aspects of microbial bioplastic production. Nutrition depletion such as nitrogen scarcity induced stressful growth conditions that resulted in highest accumulation of the biopolymer PHB. Optimizing nitrogen availability is key to maximizing PHB production, making it a viable sustainable alternative to conventional plastics.