THE EFFECT OF HEAVY METALS ON THE NITROGEN FIXATION ACTIVITY OF CYANOBACTERIA

Abstract

In this study, the effect of heavy metals Cu²⁺ and Co²⁺ on the nitrogen fixation activity of salt-tolerant cyanobacteria Nostoc calcicola and Anabaena variabilis at concentrations of 10–50 mM was studied. According to the results determined based on the acetylene reductase method, nitrogen fixation activity was maintained at 85.30–97.26% at concentrations in the range of 10–30 mM, while at a concentration of 50 mM, nitrogen fixation activity in different strains decreased to an average of 71.54%. The differential resistance of cyanobacteria to Cu²⁺ and Co²⁺ ions allows them to be considered as promising microorganisms for bioremediation processes in areas contaminated with metals.