Comparison of Light Intensity Effect on Microalgal Growth in Cactus-like and Cylindrical Photo Bioreactors

Improving photobioreactor performance for microalgae cultivation has been the aim of many researchers over the past few years. One of the primary challenges associated with existing photobioreactors is light penetration. An effective photobioreactor design should maximize light penetration, ensuring uniform illumination throughout the reactor. This study aims to assess the impact of light intensity on microalgal growth from the perspective of energy efficiency and productivity in two photobioreactors. A novel cactus-like and a cylindrical photobioreactor were designed and fabricated using three-dimensional printing technology. These two photobioreactors were used to cultivate two strains of microalgae. The novel photobioreactor achieved a maximum biomass productivity of 1 g/L/d and a maximum energy efficiency of 0.31 g/d/kWh. The cylindrical photobioreactor reached a maximum biomass productivity of 0.74 g/L/d and energy efficiency of 0.22 g/d/kWh. The increase in biomass productivity can be linked to enhancements in the photobioreactor’s surface-to-volume ratio and better light utilization.