Pure Algae Denmark ApS is a biotechnology company based in Grenaa, Denmark, specializing in sustainable, land-based seaweed cultivation systems. Founded in 2018 by Esben Rimi Christiansen, the company emerged from his master's thesis at Aarhus University, which explored the potential of sea lettuce (Ulva spp.) for public health and sustainability. Pure Algae has developed modular, plug-and-play bioreactor systems designed for land-based seaweed cultivation. These systems integrate with recirculating aquaculture systems (RAS), capturing CO₂ and nitrogen compounds from fish farming wastewater to grow high-quality seaweed biomass. Their focus is on cultivating Ulva species (sea lettuce), known for rapid growth and applications in food, feed, and pharmaceuticals. A notable product is the VALUEFARM system, which supports Integrated Multi-Trophic Aquaculture (IMTA) by transforming nitrogen, phosphorus, and CO₂ into seaweed and purified water.