Optimization of microalgal growth parameters for enhanced biohydrogen production via biophotolysis in Chlorella sp.

(30 ppm). An optimal temperature of 30 °C also maximized hydrogen production. Under these conditions, hydrogen production increased as cell density decreased due to metabolic shifts. Scale-up experiments achieved a 405-fold increase in hydrogen yield, demonstrating the scalability potential of the process. These findings emphasize the importance of optimizing algal growth conditions to balance microalgal growth and biohydrogen production for future industrial applications.