Optimisation de la solubilisation du phosphate par une rhizobactérie

Abstract

Phosphate solubilization by bacteria represents a promising alternative for improving the availability of this macronutrient in the soil. In our study, a bacterial isolate "LP1a", previously isolated by the "LMBV" laboratory, was assessed for its ability to solubilize tricalcium phosphate using qualitative and quantitative tests. The solubilization assessment on NBRIP medium showed a soluble phosphate concentration reaching 250 μg/mL. In order to optimize this capacity and improve the culture conditions, statistical approaches were employed. First, a Plackett–Burman design was used to evaluate the influence of 8 factors on solubilization and to identify which ones are the most significant. The steepest ascent method was then applied to approach the optimal response zone. Furthermore, the optimization allowed the determination of a stationary point (Glucose = 8.723, (NH₄)₂SO₄ = 1.549, pH = 6.519) associated with a predicted maximum solubilization of 287.97 μg/L. Similarly, a prediction of the optimal conditions leading to a maximum solubilization of 312 μg/L was obtained.