Production of protein biomass from Chlorella vulgaris using foliar fertilizer nutrients

One of the main challenges for industries in microalgae cultivation is the cost of their culture media. In this study, the use of two foliar fertilizers as alternative and lower cost culture media (MFF) for the production of Chlorella vulgaris compared to a control medium (BG11) was analyzed. The results for the MFF showed that on day 7 cell counts of up to 1.11 × 10 7 cells/mL were obtained, in addition to a biomass yield of up to 0.32 g.L −1 with an N:P ratio of 20:1. The highest protein content with MFF was on day 7, reaching maximum values (on a dry basis, db) of 54 g/100 g, however, lipids (1.48 g/100 g db) were low compared to literature. In addition, antiradical activity was observed by DPPH and ABTS methods and reducing power by FRAP method, supported by the presence of phenolic compounds and carotenoids, which increased significantly (p < 0.05) between day 7 and 10 of cultivation. It is concluded that the MFF allow obtaining a significant amount of protein biomass on day 7, comparable to that of a control culture medium and that in addition, this biomass is rich in bioactive compounds that increase with the depletion of nutrients in the medium. • Protein biomass of Chlorella vulgaris (54 g/100 g) in 7 days with alternative nutrients. • Biomass with yields comparable to those obtained with a conventional culture medium. • Anti-radical capacity and reducing power, demonstrated by two different mechanisms. • Phenolic and carotenoid compounds significantly increased after 10 days of culture.