CHAPTER 2: Microalgal Biorefineries: Key Processes and Main Challenges

Microalgal biorefineries have been proposed as an excellent opportunity to take advantage of the wealthy composition of microalgal biomass and sustainably supply the market needs with a wide diversity of compounds (e.g., lipids, carbohydrates, proteins, pigments, vitamins and antioxidants). Although very promising, microalgal biorefineries present some limitations that should be addressed for successful deployment at scale. These include the scalability of the process and challenges faced within the microalgal biomass production and processing chain: (i) laboratory-scale experiments to define microalgal strain and optimal conditions for attaining high biomass and target compounds' productivities; (ii) improvement of biomass productivities and induction of target products' accumulation through the selection of an adequate cultivation system and operation mode; and (iii) selection of adequate downstream processes for biomass recovery, cell disruption and product extraction, taking into account the market value and regulations established for the target compounds. This chapter highlights the main challenges and process options faced in each step of microalgal biorefineries.