Valorization and upgrading of the nutritional value of seaweed and seaweed waste using the marine fungi Paradendryphiella salina to produce mycoprotein

In this work, we have valued and increased the nutritional value of Macrocystis pyrifera and seaweed waste from brown macroalgae through a submerged fermentation process with the marine fungus Paradendryphiella salina. The product resulting after fermentation, the mycelium of P. salina together with the hydrolyzed algal, is called mycoprotein. We analyze the nutritional composition (carbohydrates, protein, amino acids, total fibre, caloric energy, fat), phenolic compounds and antioxidant activity in vitro of the mycoprotein obtained and of the algal biomass before fermentation. The content of total protein increased similar to 141% in fermented M. pyrifera and the total amino acids increased 73,5%. While that in fermented seaweed waste the protein increased similar to 131%. Furthermore, the fermentation on M. pyrifera and seaweed wastes had a positive effect on total carbohydrate reduction of this biomass algal similar to 38% and 35%, respectively. The concentration of the main complex polysaccharide presents in M. pyrifera, the alginate, was decreased significantly (up to 1.5-fold). In contrast, the cellulose concentration in fermented seaweed waste was significantly lower than the unfermented seaweed (up to 2.9-fold). According to these results, fermentation seems to enhance the nutritional value of seaweed biomass, and its potential is compared with Quorn, the mycoprotein used in food. Additionally, the total compounds phenolic and the antioxidant activity of fermented seaweed biomass exhibited an increase significantly face the unfermented seaweed biomass. Fermented seaweed waste resulted in the highest value of total phenolics and higher antioxidant activity, with an increase of 180.9 and 86.3%, respectively. Finally, this work shows that P. salina can assimilate brown macroalgae and even wastes of this biomass and produce mycoprotein like a promising strategy, and that may be useful food or functional food and feed.