Nitrogen-fixing cyanobacterial consortia are an alternative to the indiscriminate use of chemical fertilizers that affect the environment, fix atmospheric nitrogen, and can therefore be used as plant growth promoters, synthesize various substances such as auxins, vitamins, and total proteins, and fix atmospheric biofertilizers and soil conditioners. The present study aimed to obtain and develop, by biotechnological means, two consortia of cyanobacteria isolated from the root and rhizosphere of Carica papaya grown in sandy loam soil. The culture was carried out in Blue Green Medium without modified nitrogen (BG11₀), with aeration of 0.32 L min⁻¹, at a light intensity of 48.83 μEm⁻²s⁻¹, and a temperature of 22 ± 2 °C. Two consortia consisting of Nostoc commune, Aphanothece minutissima, Planktothrix sp. (C1), Nostoc commune, Calothrix sp., and Aphanothece minutissima (C2) were isolated and morphologically identified. The effective development of these consortia was verified at the laboratory level by obtaining biomass in dry weight as well as photosynthetic pigments, proteins, carbohydrates, and lipids. Germination parameters were determined in seeds of Cucumis sativus L. var. Market plus treated with the nitrogen-fixing cyanobacteria consortia, obtaining a higher germination percentage (>90%), greater root length (>6 cm), and higher vigour index I (513), II (13.02) for the C2 consortium. This broadens the spectrum of rhizosphere-derived microorganisms with potential as growth biostimulators.

The growing demand for sustainable agriculture necessitates innovative strategies to enhance crop productivity while minimizing environmental impact. This study explores the biopriming potential of Cucumis sativus L. seeds using extracts derived from a consortium of nitrofixing cyanobacteria Nostoc commune, Calothrix sp., and Aphanothece minutissima subjected to static magnetic field (SMF) treatments. The cyanobacterial consortia were exposed to SMF at varying magnetic inductions (40–50 mT and 100–200 mT), followed by extract preparation and application as biopriming agents. Results demonstrated significant improvements in key seedling growth parameters, including root and stem length, vigor index I, and fresh biomass. The consortium treated with 40–50 mT SMF showed the most pronounced growth-stimulating activity, suggesting enhanced bioactive compound production under this treatment that might be related to auxin biosynthesis. Biopriming with cyanobacterial extracts maintained a balanced nutritional uptake and plant health, as indicated by stable fresh weight dry weight ratios. These findings highlight the potential of SMF-enhanced cyanobacterial consortia as biopriming agents for horticultural crops. Future research should elucidate the underlying modes of action and optimize conditions for broader crop applications.