Multispecies Biofilms of PGPR Strains with Antibacterial Potential as a Basis for the Development of Effective Biopreparations

Abstract Rhizosphere biofilm communities exhibit stress resistance, efficient resource use, and species diversity, though lab studies typically focus on mono- and binary cultures. This research aimed to investigate multispecies biofilms of PGPR strains with antibacterial potential for biofertilizer development. Three Pseudomonas strains showing antagonistic activity against rhizobia were identified. Cocultivation of PGPR strains with Rhizobium sp. LPi14 resulted in a synergistic effect, producing a modified multispecies biofilm with enhanced biomass. The cultures demonstrated growth-stimulating activity, and experiments confirmed productive symbiosis between Rhizobium sp. LPi14 and legumes. The obtained results confirm the feasibility of introducing biofilm biofertilizers containing associations of rhizosphere bacteria with PGPR properties and antagonistic activity into agricultural practices.