Abstract
Brown macroalgae constitute 40% of the global production of seaweed, corresponding to approximately 10 million tonnes annually. Traditionally, seaweeds have been the source of hydrocolloids, food, and feed products. Due to possibilities for large-scale farming, brown macroalgae are a biomass with considerable potential for increased utilization. The main constituent polysaccharides, being alginate, cellulose, laminaran, and fucoidan, are the components of greatest importance for biorefinery usage. The polysaccharides can be extracted and applied for their physical or bioactive properties or used as a carbon source for microbial conversions to biofuels and commodity chemicals. The structural complexity and heterogeneous sugar composition of the polysaccharides make them a challenging biorefinery feedstock. These challenges can be overcome by the increasingly innovative biocatalytic tools, enzymes and microbes, that are being developed and that can be expected to open new opportunities and expand the product portfolio. However, there are still knowledge gaps, and further understanding is required on the molecular level of these interesting polymers, the tools, the refining possibilities, as well as transforming this knowledge to innovations—processes and products.