Kelp mariculture in Spain, a promising source for biofuel (ethanol) production and other valuable products

Bioethanol is the most widely used biofuel for transportation. Kelps (i.e. large brown algae) contain 50– 60% carbohydrates of the dry weight, which represent a potential sugar source for microbial conversion into bioethanol. Scientific and technological advances on ethanol production from kelps have been extensively developed over the years, more particularly with regard to the hydrolysis and fermentation of complex carbohydrate such as alginate. Currently, kelp biomass has been proved as a suitable feedstock for bioethanol production and it has begun to go into industrial application. In addition, these macroalgae are already intended for direct human consumption and used as raw material for the alginate industry, animal feed and fertilizers. All these uses and applications are expected to be integrated into kelp biorefineries and supplied by marine farming. Besides its economic value, kelp mariculture would provide significant environmental benefits such as carbon and nitrogen sequestration, reducing carbon dioxide emissions and nutrient loads from the fish farming in coastal waters. Consequently, in the Spanish Atlantic coast, kelp mariculture may be in the near future an alternative, renewable, sustainable and environmentally friendly source for bioethanol production and many other valuable products. Herein, we describe the current progress in kelp mariculture at the commercial scale based on experiences in the Atlantic coasts of Spain. The up-to-date progress in converting kelp biomass into bioethanol is also reviewed. Finally, we provide a description of the process where kelp production (mariculture), it’s processing and uses (biorefinery) are merged.