Extraction of Microalgal Bioactive Compounds Towards Functional Ingredients: A Biorefinery Approach with Prospects And Challenges

Algal bioactive compounds, including pigments, polyunsaturated fatty acids, vitamins, proteins and phenolic compounds, have a wide range of increasing applications in the pharmaceutical, nutraceutical, feed, food, and cosmetics sectors. Extraction of such compounds with the purpose of obtaining nutraceutical and food ingredients at large has been under scrutiny over the last years towards greener and more sustainable bio-based processes. The step of the extraction is indeed considered the most expensive in algal-based industrial bioprocess, mainly owing to the high processing costs and environmental impacts. Therefore, the application of a biorefinery strategy (for biomass reutilization, via choice of specific green and generally recognized as safe solvent), will certainly help attain a more feasible and competitive solution. Furthermore, emerging extraction technologies are potentially suitable for application at a large scale, as part of a multi-integrated extraction strategy. This chapter accordingly addresses the most important (micro)algal-compounds possessing bioactivities, and already or likely to be used as functional ingredients; in addition, extraction procedures thereof are discussed, bearing in mind a biorefinery strategy – with major prospects and associated challenges.