Fed-batch cultivation of Arthrospira platensis using carbon dioxide from alcoholic fermentation and urea as carbon and nitrogen sources

It was evaluated the Arthrospira platensis cultivation using CO2 from alcoholic fermentation and either urea or nitrate as nitrogen source at different light intensities (60 ≤ I ≤ 240 μmol photons m-2 s-1). Whereas the CO2 source (pure CO2 or from alcoholic fermentation) did not influence the maximum cell concentration (Xm), cell productivity (PX) and nitrogen-to-cell conversion factor (YX/N), the use of urea instead of nitrate led to higher YX/N values. Xm and PX increased when I was increased from 60 to 120-240 μmol photons m-2 s-1. Using CO2 from alcoholic fermentation, the best performance (Xm = 2952 ± 35 mg L-1, PX = 425 ± 5.9 mg L-1 d-1 and YX/N = 15 ± 0.20 mg mg-1) was obtained at I = 120 μmol photons m-2 s-1 with urea. The results obtained in this work demonstrate that urea and CO2 from alcoholic fermentation could be simultaneously used in large-scale cultivations to reduce the environmental impact associated to the release of this greenhouse gas as well as the production cost of cyanobacteria.