Optimization of oxalic acid production by fungi for biotechnological solubilization of rock phosphate

This study describes a biotechnological strategy for producing and applying oxalic acid to solubilize phosphorus (P) from rock phosphate (RP). We evaluated six fungal species (Aspergillus niger FS1, Penicillium islandicum FS41, Pleurotus ostreatus PO1, Rhizoctonia solani Rhiz555, Sclerotium rolfsii Sr25, Sclerotinia sclerotiorum Scl134) three culture media (potato dextrose broth, Tsao Strasser media) maximize production. Among the isolates tested media, S. Sr25 medium showed efficient was optimized following response surface methodology after initial screening of factors affecting RP solubilization. The concentrations were 1 g L–1 NaNO3, 100 glucose, 2 KH2PO4, 4.5 yeast extract, 25 mg MgSO4·7H2O used 20 days incubation. Under these conditions, 71 mmol obtained, representing three-fold increase over production under non-optimized conditions (20 L–1). produced by reacted with low-solubility solubilized % P contained in ore. Thus, using produce seems promising alternative solubilization RP.