Green extraction of bioactive compounds from microalgae and seaweeds

Algae (macroalgae and microalgae) are a large and diverse group of organisms that can be produced in a sustainable manner and with the capacity to synthesize a wide variety of compounds, including polysaccharides, proteins-peptides, lipids, polyphenols, and carotenoids, that could be exploited as high-value ingredients and nutraceuticals, amongst other applications. The commercial exploitation of these compounds relies on their extraction from biomass by conventional processes that require the use of large amounts of chemicals and energy inputs, increasing the safety and sustainability concerns of these operations. This chapter aims to cover several aspects of the innovative technologies currently being explored for their potential to develop green extraction processes from algae, including the main equipment and principles underlying the operation of ultrasounds, microwaves, and pulsed electric fields. The recent technological developments aiming to combine the use of these promising technologies with other innovative or conventional processes, as well as the sustainability efforts of the algal sector to develop bio-refineries or full exploitation models of the biomass involving zero-waste processes, will also be covered in this chapter, together with the future and main challenges in this field of research.