The article presents the results of the study of nitrogenase activity of five strains of cyanobacteria from the collection of phototrophic microorganisms of Al-Farabi Kazakh National University and their effect on the growth of strawberries. Nitrogen-fixing cyanobacteria were studied by strains Anabaena variabilis R-I-5, Anabaena sp. 7912, Anabaena sp. Z-1, Nostoc calsicola RI-3, Nostoc sp. S-2, and according to the results obtained high activity of nitrogenase in the strain Anabaena variabilis

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... R-I-5. In the study of the effect of cells of different concentrations of the strain Anabaena variabilis R-I-5 on the growth of strawberry Strawberry Sunrise T-4, it was found that its suspension of 24x10 6 cells/ml and 48x10 6 cell/ ml had a positive effect on strawberry growth. In addition, an increase in the number of strawberry roots was observed in the suspension of cyanobacterial biomass 24x10 6 cell/ml. An increase in the number of strawberry leaves, root length, stem height and a significantly higher yield of dry biomass of strawberries were observed in the suspension of the study in the amount of 48x10 6 cell/ml. The optimal cell count of the nitrogen-fixing cyanobacterium Anabaena variabilis R-I-5 suspension, which has a positive effect on the growth of strawberry plants, was 48x10 6 cell/ml. The obtained results allow to use the nitrogen fixing strain Anabaena variabilis R-I-5 for obtaining biological products in agrobiotechnology.