A low-cost approach for Chlorella sorokiniana production through combined use of urea, ammonia and nitrate based fertilizers

In this study, the use of combined nitrogen sources (urea, ammonia and nitrate) in a medium formulation is proposed as part of a low-cost approach for the cultivation of Chlorella sorokiniana. The “Blue Green Nitrogen Mix” (BGNIM) medium, was able to support algal growth at similar levels of biomass productivities compared to the widely used BG11 medium varying between 47 and 50 mgDW·L^{− 1}·d^{− 1}. The combined use of nitrogen sources led to alterations in metabolites production. Protein abundance increased 7%, carotenoids 41%, soluble sugar 12%, alanine 370%, serine 350%, valine 180%, myo-inositol 190%, glyceric acid 230% and glutamic acid 220% when compared to BG11 standard medium. Additionally, a large pH shift was detected during the initial part of the growth curve in BGNIM cultures, opening opportunities for control of pH sensitive predators during large-scale production. Importantly, the BGNIM formulation provided a cost reduction of approximately 95% compared to BG11 standard medium.