This is a book that has been divided into 9 chapters, including information on the recovery of highly valuable compounds for microalgae. The authors of this volume discuss seaweed as a renewable and globally available feedstock with potential applications in the food and feed industries, as well as the agricultural, chemical, or pharmaceutical fields. The chapters include discussions on a wide range of topics including an overview of seaweed by-products, Algae and microalgae biorefineries, the potential use of seaweed by-products in various products and materials, colour stability, and pigment contents of powdered laver (Pyropia yezoensis). The text also includes the interactions of the algae Sargassum muticum with metals as a starting point for the valorisation of invasive seaweed species, as well as new insights into the nutrition and functionality of seaweed. Microalgae biomass as an ingredient to design added value in food products, as well as seaweed biomass for bioremediation or Ethanol creation are additional topics.