Macrocystis pyrifera in the circular economy: Advances in cultivation, processing, and industrial integration

The escalating pressure on existing production systems due to an increasing world population and limited availability of arable land, compounded by increasing atmospheric carbon dioxide concentration, has prompted the search for sustainable sources of macro- and micronutrients for use in industrial applications. Macroalgae or seaweeds are macroscopic marine algae that have been traditionally consumed in Asian countries for centuries. Because of their composition, wide availability, and growth-associated environmental benefits (i.e., carbon uptake, support to fishery habitats, and reduced dependence on fresh water, arable land, and fertilizer needs), macroalgae have been highlighted as a potentially sustainable biomass feedstock for the production of a wide range of polysaccharides (i.e., laminarin, fucoidans, alginate), growth hormones, proteins, and phenolic compounds (phlorotannins) which could potentially be used in human nutrition, animal feed, production of bio-stimulants or fertilizers for plant growth, biotherapeutic, cosmetic, and food applications. However, full utilization of macroalgae’s potential relies on the development of bio-guided processing strategies that are able to not only maximize the extractability of the diverse compounds, but also preserve the functional and biological properties of the extracts. This review highlights the use of brown macroalgae, focusing on the giant kelp Macrocystis pyrifera when possible, as a feedstock to produce added-value compounds. The scope encompasses sea farming, harvesting systems, and downstream processing conditions, with emphasis on innovative attempts to develop structure/function-based extraction methods to produce components with desired properties.