Medium pH, carbon and nitrogen concentration modulate the phosphate solubilization efficiency of Penicillium purpurogenum through organic acid production.

SCERVINO J.M; V.L. PAPINUTTI; M. S. GODOY; M.A. RODRIGUEZ; I. DELLA MONICA; M. RECCHI; M. J. PETTINARI; A.M. GODEAS

JOURNAL OF APPLIED MICROBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: England; Año: 2011 p. 1215 - 1223

1364-5072

Tricalcium phosphate solubilization efficiency of Penicillum purpurogenum, the most efficient phosphate (P) solubilizer among several microorganisms screened,was evaluated at acid or alkaline pH using different C and N sources. Glucose- and NH-based media showed the highest P-solubilization values followed by fructose. P. purpurogenum solubilizing ability was higher in cultures grown at pH 6.5 than cultures at pH 8.5. Organic acids were detected in both alkaline and neutral media, but the relative percentages of each organic acid differed. Highest P release coincided with the highest organic acids production, specially gluconic acid. When P. purpurogenum grew in alkaline media the organic acids nature and concentration changed at different N and C concentrations. A factorial categorical experimental design showed that the highest P solubilization, conciding with the highest organic acids production, corresponded to the highest C concentration and lowest N concentration Conclusions: The results described in the present study show that media pH and carbon and nitrogen concentration modulate the P solubilization efficiency of P. purpurogenum through the production of organic acids, and particularly that of gluconic acid. In the P solubilization optimization studies, glucose and NH as C and N sources allowed an adequate solubilization efficiency in high pH. Significance and Impact of the Study: This organism is a good potential soil inoculant, especially in P-poor alkaline soils where other P-solubilizers fail to release soluble P. Further work is necessary to elucidate if these results can be extrapolated to natural soil ecosystems, where different pH values are present. P. purpurogenum could be used to develop a bioprocess for the manufacture of phosphatic fertilizer with these substrates.