title: Simultaneous use of urea and potassium nitrate for Arthrospira (Spirulina) platensis cultivation.
abstract: Urea has been considered as a promising alternative nitrogen source for the cultivation of Arthrospira platensis if it is possible to avoid ammonia toxicity; however, this procedure can lead to periods of nitrogen shortage. This study shows that the addition of potassium nitrate, which acts as a nitrogen reservoir, to cultivations carried out with urea in a fed-batch process can increase the maximum cell concentration (X(m) ) and also cell productivity (P(X) ). Using response surface methodology, the model indicates that the estimated optimum X(m)  can be achieved with 17.3 mM potassium nitrate and 8.9 mM urea. Under this condition an X(m)  of 6077 ± 199 mg/L and a P(X)  of 341.5 ± 19.1 mg L(-1) day(-1)  were obtained.
authors: Department of Biochemical and Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 580, São Paulo, Brazil.
authors: Denise C M
authors: DC
authors: Vieira
authors: Marcelo C
authors: MC
authors: Matsudo
authors: Sunao
authors: S
authors: Sato
authors: Attilio
authors: A
authors: Converti
authors: João C M
authors: JC
authors: de Carvalho
mesh_terms: D018533:Biomass; D001709:Biotechnology / Q000379:methods*; D018929:Cell Culture Techniques; D049109:Cell Proliferation; D003470:Culture Media / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D015999:Multivariate Analysis; D009566:Nitrates / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D017680:Potassium Compounds / Q000378:metabolism*; D012044:Regression Analysis; D053545:Spirulina / Q000254:growth & development* / Q000378:metabolism*; D014508:Urea / Q000378:metabolism*
chemical_list: D003470:Culture Media; D009566:Nitrates; D017680:Potassium Compounds; D014508:Urea; D009584:Nitrogen; C023844:potassium nitrate