Exploring the impact of light-emitting diodes and pH on microalgae Spirulina biomass production optimization using a central composite design

This study explores the cultivation of Spirulina platensis, a microalgae species, under various lighting conditions and pH levels to maximize biomass production. The organism primarily relies on light for autotrophic growth, and both light intensity and quality shape its cell growth and biomass composition. The investigation assessed the impact of different light-emitting diodes on Spirulina's dry biomass yield. A central composite design (CCD) and response surface methodology (RSM) were implemented for experimental design and optimization of cultivation procedures, examining light duration (7-14 h) and pH values (7-10). Optimum biomass yield was achieved under 14 h of light exposure at a pH level of 8.5, with dry biomass also peaking at these conditions. A verification test corroborated the predictive accuracy of these findings. The highest average dry cell weight, 2.07 +/- 0.12 g/L, was attained under white light-emitting diode, followed by 1.95 +/- 0.23 g/L under red light. This research sheds significant light on optimal conditions for S. platensis cultivation, demonstrating how the species responds to different light sources and pH levels, thereby providing valuable insights for enhancing biomass production.