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.