Production of polyhydroxybutyrate with high cell density cultivation using thermophile Caldimonas thermodepolymerans

This study investigates the production of polyhydroxybutyrate (PHB) using the thermophilic bacterium Caldimonas thermodepolymerans in fed-batch fermentation. This research highlights the potential of thermophilic bacteria in biopolymer production due to their ability to operate at high temperatures, which reduces contamination risks and enhances energy efficiency. Optimal fermentation conditions were identified at a temperature of 50 °C, with the strain achieving a maximum specific growth rate (μ_max) of 0.57 h⁻¹ and high biomass concentration of 63.1 g_CDW/L. PHB production reached a peak concentration of 31.9 g/L with a productivity of 1.30 g_PHB/L/h. The high cell density approach in fed-batch fermentation not only maximizes the productivity and yield of PHB, but also optimizes the production process, making it more suitable for industrial-scale applications. The findings highlight the potential of thermophilic bacteria as a sustainable solution for enhancing PHB production and advancing biodegradable polymer synthesis.