Advancements in photobioreactor systems: Optimizing operations for enhanced microalgal growth and bioremediation

Abstract

Photobioreactors (PBRs) are critical for sustainable production of biofuels, high-value compounds, and environmental services including carbon capture and wastewater treatment. This review compares tubular, flat-panel, vertical column, hybrid, and membrane-integrated PBRs, analyzing how geometry and operating strategies influence light utilization, mass transfer, nutrient delivery, and scalability. Recent performance data on illumination regimes, gas–liquid transfer rates, biomass productivity, and biochemical yields are synthesized to link engineering design with cultivation outcomes. Persistent challenges include oxygen accumulation, fouling, high energy demand, and scale-up limitations. Emerging solutions such as LED-based spectral control, modular hybrid configurations, and membrane-assisted biomass retention show strong potential. The review's distinctive contribution is a design-to-performance framework that connects reactor configuration and operational parameters to growth rates, product yields, and techno-economic viability. Future priorities include integrating computational fluid dynamics with kinetic growth models, developing low-energy gas transfer technologies, applying image-based monitoring for early contamination detection, and tailoring designs to local water, land, and regulatory conditions. By combining technical, environmental, and economic insights, this work provides a practical pathway toward cost-effective, scalable, and sustainable microalgae cultivation.