Year-round cultivation of marine macroalgae Enteromorpha prolifera using photobioreactors

Marine macroalgae – next-generation renewable feedstock is a potential solution to the growing need for sustainable future resources, with seaweed protein to cater to the ever-increasing demand of feeding the fast-growing population. The conventional cultivation methods for marine macroalgae are impeded by low productivity, seasonal constraints, and climate change issues, necessitating improved cultivation strategies. The present study demonstrates the use of tank-based (T-PBR) and vertical (V-PBR) outdoor photobioreactors for free-floating substrate-independent land-based cultivation of filamentous green seaweed Enteromorpha prolifera. Optimization of the stocking density (SD) for seasonal variation was carried out to attain maximal biomass productivity. The study demonstrated biomass production with average annual productivity of 480 g fw m−2 d−1 in V-PBR and 413 g fw m−2 d−1 in T-PBR. The season-specific SD, carbon dioxide supplementation (5%), and nutrient supply management ensured a year-round consistent supply of E. prolifera biomass. In spite of seasonal variation in biomass quality and quantity, an annual average content of 24% protein and 51% carbohydrate was observed. The present work substantiates the advancement of land-based seaweed cultivation for sustainable vegan protein production.