Spirulina maxima is a cianobacter of great interest to the production of nutritious and therapeutic substances. It is mesophilic, essentially fotoautotrophic and has preference for media with high alkalinity. Its principal nitrogen source are nitrates and ammonium salts or urea [1, 2, 3, 10, 16]. Spirulina maxima was cultured in fermentors with 3 liters of medium proposed by PAOLETTI, PUSHPARAJ & TOMASELLI [7] exposed at light with intensity of 2400lux and in two other media in which the KNO3 concentration was reduced from 2.5 to 0.2g/L KNO3 and zero, that were denominated 2.5N and 0.2N and medium without KNO3 SN respectively. In cultures at 35ºC a reduction of the percentage of proteins was observed, in the dry cellular mass, of 28.84% and 32.87%, an increased of 30.34% and of 54.21% in carbohydrates and total lipids of 287.90% and 277.37%, when it was used the media 0.2N and SN instead the medium 2.5N respectively, except the percentage of ashes that showed no significant variation. When the temperature was reduced from 35 to 25ºC, the percentage of protein in the dry mass decreased 40.28% and 39.02%, while the percentage of carbohydrates increased 88.9% and of 91.15% and percentage of total lipidic increased 321.25% and of 307.08%, when it was used the media 0.2N and SN instead of the medium 2.5N respectively. The percentage of ashes showed no significant variation. The data showed a sensitive alteration in the cellular mass composition when the percentage of nitrogen and the cultivation temperature were decreased.
Spirulina; biomass; microalgae; centesimal composition
