Estratégias microbianas de solubilização de fosfato e seus perfis metabólicos: uma análise comparativa entre cepas comerciais e bioprospectadas

Abstract

The availability of nutrients is one of the key factors influencing agricultural production. Among these, phosphorus (P) is one of the most limiting elements due to its low availability to plants. This is particularly true in Brazilian soils, where phosphorus predominantly exists in the form of Calcium Phosphate (Ca3(PO4)2), Aluminum Phosphate (AlPO4) e Iron Phosphate (FePO4), which are insoluble and have low root absorption. Consequently, the reliance on imported phosphate fertilizers has driven the search for more efficient alternatives to this non-renewable resource. In this context, the use of phosphate-solubilizing microorganisms has shown to be an economically viable alternative to mitigate the environmental impact associated with the use of chemical fertilizers. The present study aims to evaluate the phosphate solubilization potential and metabolite profile of the strains bb4a-ebc59 and bb4a-bbc56, both from the BioBank4Agro collection. The assays were also conducted using the commercial product BiomaPhos® (marketed as a phosphate-solubilizing agent) as the positive control. The qualitative experiment was performed on solid medium in Petri dishes, while the quantitative experiment was carried out in liquid medium. Following the assessment of solubilization potential, a metabolomic approach was employed to gain a better understanding of the biochemical mechanisms involved in phosphate solubilization. In the qualitative assay, the commercial strains exhibited a higher solubilization index (SI). In the quantitative assay, the treatment in which the two BioBank4Agro strains were combined showed the highest solubilization, as well as the most pronounced pH decrease. The metabolic investigation revealed the presence of organic acids, which have both direct and indirect associations with solubilization. It was concluded that the two studied strains demonstrated phosphate solubilization capacity, being more efficient when combined, and that part of the solubilization process may be associated with the presence of organic acids