Synthetic Biology and Metabolic Engineering of Microalgae for Sustainable Lipid and Terpenoid Production: An Updated Perspective

Microalgae are increasingly recognised as powerful platforms for the sustainable production of lipids and terpenoids, with expanding applications in the food, fuel and biomanufacturing industries. In this updated review, we consolidate and critically assess the most recent advances in synthetic biology and metabolic engineering of key microalgal models, including Chlamydomonas reinhardtii, Nannochloropsis spp. and Phaeodactylum tricornutum. We focus on developments that have emerged in the latest waves of research, emphasising novel genetic toolkits that accelerate the Design-Build-Test-Learn (DBTL) cycle, breakthroughs in genome-scale metabolic modelling, and innovative strategies for organelle-targeted biosynthesis of high-value compounds. Recent case studies are compared to highlight trends in successful engineering approaches. By capturing these up-to-date insights, this review outlines the current trajectory of microalgal biotechnology toward scalable, carbon-neutral biofactories for polyunsaturated fatty acids (PUFAs) and diverse terpenoids, reinforcing their role in global sustainability and the circular bioeconomy.