Microalgae-Derived Biodiesel as a Scalable and Sustainable Pathway for Next-Generation Biofuels

Abstract

Microalgae-derived biodiesel is increasingly regarded as a next-generation renewable fuel because microalgae combine rapid biomass growth, high lipid productivity, carbon dioxide capture, and cultivation on non-arable land or nutrient-rich wastewater. This review critically integrates recent progress in strain improvement, cultivation engineering, harvesting, lipid extraction, and conversion technologies for scalable biodiesel production. Advances in genome editing, two-stage cultivation, hybrid photobioreactor-open pond systems, and microwave- or ultrasound-assisted extraction have improved lipid yield and process efficiency. Digital tools, including artificial intelligence, predictive monitoring, digital twins, and machine-learning-based contaminant control, are also emerging as important enablers of automation and scale-up. Embedding microalgae production within circular biorefineries can support flue-gas utilization, nutrient recycling, and co-production of high-value compounds such as astaxanthin, omega-3 fatty acids, phycobiliproteins, proteins, and biodegradable biopolymers. Nevertheless, commercialization remains constrained by high cultivation costs, energy-intensive dewatering, variable outdoor productivity, and uncertain policy incentives. Integrated techno-economic optimization, carbon-credit mechanisms, and multi-product biorefinery models are therefore essential for advancing microalgae biodiesel toward industrial deployment.