A review of biodiesel production from microalgae

As the search for alternatives to fossil fuels continues, microalgae have emerged as a promising renewable feedstock for biodiesel. Many species contain high lipid concentrations and require simple cultivation—including reduced freshwater and land area needs—compared to traditional crops used for biofuels. Recently, technological advancements have brought microalgae biodiesel closer to becoming economically feasible through increased efficiency of the cultivation, harvesting, pretreatment, lipid extraction, and transesterification subsystems. The metabolism of microalgae can be favorably manipulated to increase lipid productivity through environmental stressors, and “green” techniques such as using flue gas as a carbon source and wastewater as a media replacement can lower the environmental impact of biodiesel production. Through life cycle assessment and the creation of process models, valuable insights have been made into the energy and material sinks of the manufacturing process, helping to identify methods to successfully scale up microalgae biodiesel production. Several companies are already exploring the microalgae industry, offsetting operating costs through isolation of co-products and careful unit operation selection. With numerous examples drawn from industry and the literature, this review provides a practical approach for creating a microalgae biodiesel facility.