Innovative cultivation solutions and technologies

Marine microalgae are primary producers of high-quality molecules such as essential fatty acids (omega-3 and omega-6) and xanthophylls. The increasing demand for these natural and healthy commodities in different industrial sectors (such as food, feed, and nutraceuticals) has fostered the interest of companies and institutions in growing microalgae at an industrial scale to enter the market, particularly in the field of aquaculture. Nevertheless, to make this process feasible, higher biomass productivity and quality must still be ensured to cope with high capital and operational costs. This chapter addresses diverse recent innovative technologies and cultivation strategies developed to boost marine microalgae productivity both on land and offshore. Land-based photobioreactors are nowadays recognized as the main consolidated and effective technology to obtain stable and high-quality biomass. To boost the production, the overall energetic conversion efficiency can be increased by means of efficient lightning setup exploitation (such as monochromatic or pulsed light-emitting diodes) or by light partitioning through the establishment of cocultures. To reduce land consumption, microalgae can be cultivated in their native environment and exploit seawater for mixing and cooling. Floating photobioreactors are studied for this purpose, with challenges related to carbon supply and gas exchange. This technology can be coupled with the supply of bicarbonate as an additional inorganic carbon source, reducing energetic inputs and lowering the overall cost of cultivation.