INFLUENCE OF THE NUTRITIONAL SOURCES ON THE GROWTH-RATE OF CYANOBACTERIA

The comparative analysis of the growth rate of three cyanobacteria, in cultures containing various nitrogen sources, aimed to define the maximum achievable growth rates, as well as the concentrations of protein precursors most advantageous for this purpose. In this study Spirulina maxima, Oscillatoria agardhii and Oscillatoria limnetica were tested in nutritive mixtures containing defined proportions of KNO3, urea and ammonium. The most favorable findings for growth rate of O. agardhii and S. maxima occurred in the presence of KNO3 2.57 g/L, and for O. limnetica in the medium with urea 0.3 g/L. Absolute values obtained with O. agardhii and O. limnetica with different nitrogen sources were in the range of 0.8 and 0.7 d-1 respectively. In the case of Spirulina the corresponding result was 0.3 - 0.4 d-1. It is concluded that all studied nitrogen sources permitted satisfactory growth rates, according with the characteristics of each microorganism.