Microalgal Valorization of CO₂: A Sustainable Pathway to Biofuels and High-Value Chemicals

The escalating climate crisis and the imperative to transition from a fossil fuel-dependent economy demand transformative solutions for sustainable energy and carbon management. Biological CO₂ capture and utilization (CCU) using microalgae represents a particularly compelling approach, capitalizing on microalgae’s high photosynthetic efficiency and remarkable product versatility. This review critically examines the principles and recent breakthroughs in microalgal CO₂ bioconversion, spanning strain selection, advanced photobioreactor (PBR) design, and key factors influencing carbon sequestration efficiency. We explore diverse valorization strategies, including next-generation biofuel production, integrated wastewater bioremediation, and the synthesis of value-added chemicals, underscoring their collective potential for mitigating CO₂ emissions and achieving comprehensive resource valorization. Persistent challenges, such as economically viable biomass harvesting, cost-effective scale-up, and enhancing strain robustness, are rigorously examined. Furthermore, we delineate promising future prospects centered on cutting-edge genetic engineering, integrated biorefinery concepts, and synergistic coupling with waste treatment to maximize sustainability. By effectively bridging carbon neutrality with renewable resource production, microalgae-based technologies hold considerable potential to spearhead the circular bioeconomy, accelerate the renewable energy transition, and contribute significantly to achieving global climate objectives.