Strategies, perspectives and challenges of microalgae biorefineries as carbon capture and utilization technology

Carbon-fixing microorganisms including microalgae convert carbon dioxide gas into different organic building blocks: peptides, carotenoids, proteins, lipids and carbohydrates among many others. These buildings blocks are the base of high-value biochemical products such as vitamins, antioxidants and other nutraceutical supplements; pharmaceutical compounds with anti-inflammatory properties and a wide variety of human and animal food supplements. Biodiesel, bio-oil, bioethanol, biogas and bio-jet fuel can also be manufactured from microalgae. Furthermore, microalgae can be used in secondary and tertiary phases of wastewater treatment. Microalgae can be seen as a bio carbon capture and utilization method given its highly effective CO2 biofixation even at low concentrations. A sustainable zero waste biorefinery approach should be taken to optimize microalgae potential both for biofuels and bioproducts production as well as carbon sequestration. Cultivation and dewatering steps low efficiencies are the current major challenges for an economically viable microalgae biorefinery.