Improving PHB production in cyanobacteria: Modeling the optimal light regime for growth

The production of bioplastics, such as polyhydroxybutyrate (PHB), using cyanobacteria offers a sustainable alternative to conventional plastics. However, achieving economically viable production requires optimizing biomass growth. This study examined four growth models: Gompertz (empirical growth), Baranyi-Roberts (biologically dependent), Monod (nutrient dependent), and Aiba (irradiance dependent). The results indicate that a light-based model more accurately describes cyanobacterial growth and shows potential for optimizing light regimes. Additionally, an estimator was proposed to assess the potential PHB yield within the given biomass. Experiments were conducted to correlate photosynthetic efficiency with biomass production, providing deeper insights into the effects of light on growth. These findings support the development of optimized cultivation strategies, ultimately improving the economic viability of cyanobacteria-based bioplastics.