Comunidade microbiana sintética (SYNCOM) promove redução da adubação nitrogenada na bananeira

Abstract

Banana cultivation is essential for food security; however, its high dependence on nitrogen fertilizers results in increased production costs and environmental impacts. In this context, the use of Synthetic Microbial Communities (SynCom) emerges as a biotechnological alternative to enhance nutrient use efficiency. This study aimed to evaluate the agronomic efficiency of a SynCom composed of Bacillus strains and diazotrophic bacteria in promoting the growth of banana seedlings cv. Prata Catarina, with reduced nitrogen fertilizer input. The strains were functionally characterized in vitro for biological nitrogen fixation (BNF), indole-3-acetic acid (IAA) production, phosphorus solubilization and mineralization, as well as the production of biosurfactants and siderophores. Bacillus subtilis BR10788 and Azospirillum lipoferum BR11501 stood out for their high IAA production (46.06 and 43.51 μg mL⁻¹, respectively) and positive BNF activity. Phosphorus solubilization and mineralization showed low levels for all strains but indicated complementary functional potential. Azospirillum lipoferum BR11501 and Acidovorax sp. BR11652 exhibited higher biosurfactant and siderophore production, evidenced by emulsification indices of up to 68% and siderophore halos reaching 2.07 mm, highlighting their role in nutrient mobilization and root colonization. Under greenhouse conditions, co-inoculation of the selected strains (Bacillus LPPC282 × Azospirillum lipoferum BR11501 and Bacillus subtilis BR10788 × Acidovorax sp. BR11652) showed a synergistic effect superior to individual inoculation, promoting increases of up to 127.90% in shoot dry mass and 100% in root dry mass, even under reduced nitrogen levels. It is concluded that the developed SynCom exhibits high biotechnological potential, as the functional complementarity among auxin production, biological nitrogen fixation, and biosynthesis of biosurfactants and siderophores contributed to enhanced growth and biomass accumulation of banana seedlings.