Microalgae as biofactories for sustainable applications: Advancing carbon sequestration, bioenergy, and environmental remediation

Microalgae are increasingly recognized as versatile biofactories capable of transforming the global shift toward sustainable energy, environmental remediation, and circular economic systems. This review presents a comprehensive, system-level synthesis of recent advancements in microalgal technologies, emphasizing their multifunctional roles in carbon sequestration, bioenergy production, wastewater treatment, and bioplastic development. Under optimized conditions, microalgae can achieve carbon fixation rates of 1.0–3.7 g CO₂/L/day and lipid content up to 60 % of dry biomass in select strains, outperforming most terrestrial bioenergy crops. Key technologies reviewed include photobioreactor-based cultivation, hydrothermal liquefaction, integrated biorefineries, and hybrid harvesting systems. Additionally, recent breakthroughs in metabolic engineering and energy-efficient conversion methods are critically analyzed. While significant progress has been made, this review also identifies crucial research and implementation gaps that limit large-scale adoption. his review addresses these gaps by combining critical evaluations, performance benchmarking, and real-world case studies. It also identifies key commercialization bottlenecks and policy barriers that hinder large-scale deployment. Importantly, this review aligns microalgal innovation with multiple United Nations Sustainable Development Goals (SDGs), including SDG 7 (Affordable and Clean Energy), SDG 9 (Industry, Innovation, and Infrastructure), SDG 12 (Responsible Consumption and Production), and SDG 13 (Climate Action). By unifying environmental, economic, and technological perspectives, this work offers a strategic roadmap for harnessing the full potential of microalgae to meet global sustainability and climate neutrality targets. © 2025 Elsevier B.V., All rights reserved.