In recent years, microalgae have garnered interest forproducing valuable molecules ranging from therapeuticproteins to biofuels. Nutritional and medical applicationsare especially fitting for these organisms because manybiomolecules expressed by microalgae are generallyregarded as safe (GRAS) for human consumption [1,2].Although numerous species produce useful compoundsnaturally, these unicellular organisms are also well suitedfor genetic manipulation and high-throughput analysis[3,4]. Moreover, microalgae are unique because theycombine the renewable energy-capturing ability of photo-synthesis with the high yields of controlled microbialcultivation, making them potentially valuable organismsfor economical, industrial-scale production processes inthe 21st century.The overarching goal of microalgal biotechnology is toimprove the productivity of these organisms in order tomeet the demands of a rapidly growing market [5].Although much of the industry’s previous work hasfocused on cultivation techniques and species selection,novel microalgal applications are currently being broughtto fruition with the help of genetic engineering. The aimof this review is to describe the ability of microalgae tosynthesize useful products, examine methods of increas-ing yield through altered metabolism, and provide anoutlook for the future of microalgal metabolic engineer-ing.: redirecting metabolism to fuelabiotechnologyrevolution