ANALYSIS OF THE PROCESS OF GROWTH AND BIOLOGICAL NITROGEN FIXATION BY CYANOBACTERIA NOSTOC PUNCTIFORME (HARIOT) ELENKIN, CULTIVATED ON DIFFERENT NUTRITIONAL MEDIUMS
Sergiu DOBROJAN, Galina DOBROJAN, Universitatea de Stat din Moldova
Аннотация
This article presents the results of the analysis of the process of growth and biological fixation of atmospheric nitrogen, carried out by the cyanobacterium Nostoc punctiforme, cultivated on the nutrient media M.S. Taha (M), Kratz
and Myers (C), modified Detmer (De) and Drew (Dr). The highest amount of biomass was attested when cultivating
the cyanobacterium on the nutrient medium De, and the lowest on the medium Dr, as well as the values of the reproduction rate and the reproduction coefficient. When cultivating the cyanobacterium on the nutrient media studied, the
pH tends to alkalize. The highest amount of fixed atmospheric nitrogen was found when cultivating on the nutrient
media De and M, on the sixth day of the experiment, and cultivation on the nutrient medium Dr presented the lowest
intensity. Thus, it was found that the biological fixation of atmospheric nitrogen, carried out by N. punctiforme, is
subject to the legitimacy of “quantitative nitrogen self-regulation”.
Keywords: cyanobacteria, Nostoc punctiforme, growth, nitrogen fixation.
