| Summary: | Cyanobacteria, as highly adaptable microorganisms, are characterized by an
ability to survive in different environmental conditions, in which a
significant role belongs to their enzymes. Phosphatases are enzymes produced
by algae in relatively large quantities in response to a low orthophosphate
concentration and their activity is significantly correlated with their
primary production. The activity of these enzymes was investigated in 11
cyanobacterial strains in order to determine enzyme synthesis depending on
taxonomic and ecological group of cyanobacteria. The study was conducted with
4 terrestrial cyanobacterial strains, which belong to Nostoc and Anabaena
genera, and 7 filamentous water cyanobacteria of Nostoc, Oscillatoria,
Phormidium and Microcystis genera. The obtained results showed that the
activity of acid and alkaline phosphatases strongly depended on
cyanobacterial strain and the environment from which the strain originated.
Higher activity of alkaline phosphatases, ranging from 3.64 to 85.14
μmolpNP/s/dm3, was recorded in terrestrial strains compared to the studied
water strains (1.11-5.96 μmolpNP/s/dm3). The activity of acid phosphatases
was higher in most tested water strains (1.67-6.28 μmolpNP/s/dm3) compared to
the activity of alkaline phosphatases (1.11-5.96 μmolpNP/s/dm3). Comparing
enzyme activity of nitrogen fixing and non-nitrogen fixing cyanobacteria, it
was found that most nitrogen fixing strains had a higher activity of alkaline
phosphatases. The data obtained in this work indicate that activity of
phosphatases is a strain specific property. The results further suggest that
synthesis and activity of phosphatases depended on eco-physiological
characteristics of the examined cyanobacterial strains. This can be of great
importance for the further study of enzymes and mechanisms of their activity
as a part of cyanobacterial survival strategy in environments with extreme
conditions. [Projekat Ministarstva nauke Republike Srbije, br. III 43002]
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