A Comprehensive Review of Sustainable Biodiesel Production Processes from Microalgae as Third-Generation Biofuels (2026)

Abstract

The escalating global demand for energy, coupled with the environmental consequences of fossil fuel dependence, has intensified the pursuit of renewable and sustainable energy alternatives. Among these, biofuels derived from renewable biomass have emerged as a pivotal solution for reducing greenhouse gas emissions, enhancing energy security, and supporting economic growth. Microalgae-based biodiesel, categorized as a third-generation biofuel, represents one of the most promising alternatives due to algae’s high lipid productivity, rapid growth rates, and versatility in cultivation on non-arable land with minimal freshwater use. This comprehensive review evaluates the current state of algal biodiesel production, encompassing cultivation strategies, harvesting and dewatering techniques, lipid extraction, and conversion processes. Advances in algal biology, metabolic engineering, and biorefinery concepts have significantly improved process efficiencies while also highlighting the potential for co-production of high-value bioproducts, thereby strengthening the economic feasibility of algal biofuels. However, large-scale commercialization remains constrained by technical and economic challenges, notably high production costs, contamination risks, and difficulties in maintaining stable productivity. To overcome these barriers, continued research into advanced cultivation systems, cost-effective harvesting technologies, and sustainable extraction methods is essential. Additionally, supportive policy frameworks, targeted economic incentives, and international collaborations will be critical in facilitating the transition from pilot-scale projects to full industrial deployment. Ultimately, microalgae-derived biodiesel holds substantial potential to decarbonize the transportation sector and contribute to a sustainable global bioeconomy, provided that scientific, technical, and policy-driven innovations continue to advance in synergy.