MICROBIAL SOLUBILIZATION OF PHOSPHATE ROCKS FOR BIOFERTILIZER APPLICATIONS

Phosphorus is an essential element for plants and animals and despite being necessary in smaller quantities than the other macronutrients, is essential to the growth of plants and agricultural productivity. The industrial production of phosphate fertilizers uses strong inorganic acids to obtain soluble phosphate. Inoculation of phosphate solubilizing microorganisms is an alternative to replace or reduce the use of soluble phosphate fertilizers. This context evaluated the biosolubilization of phosphate rock by different fungal strains. The fungi Aspergillus niger, Trichoderma harzianum and Trichoderma asperellum were cultivated separetelly as well as in co-cultivation at different concentrations of carbon source. The cultivation of A. niger resulted in the best solubilization of the phosphate rock using 10 g/L of glucose. The co-cultivation of A. niger with T. harzianum solubilized a similar amount of phosphate, but it required a higher amount of glucose. Although no synergism in the phosphate solubilization was observed by the co-cultivation of these fungal strains, the phosphate solubilization capacity of A. niger was not hampered, suggesting that it could be used in combination with the Trichoderma strains, widely recognized as good biocontrol agents to provide additional roles for biofertilizer applications.