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

Introduction: 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.

Background: 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.

Methodology: 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).

Results: 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.

Conclusion: 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.