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

SCERVINO, J. MARTIN; PAPINUTTI, V.L.; GODOY, MANUEL; RODRIGUEZ, M.A. ; DELLA MONICA, I. ; RECCHI, M.; PETTINARI, MARIA JULIA; GODEAS, A.M.

JOURNAL OF APPLIED MICROBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2011 vol. 110 p. 1215 - 1223

1364-5072

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-bidi-font-family:"Times New Roman"; mso-ansi-language:ES; mso-fareast-language:ES;} @page Section1 {size:612.0pt 792.0pt; margin:72.0pt 90.0pt 72.0pt 90.0pt; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} -->Aims: To study phosphate solubilization in Penicillium purpurogenum as functionof medium pH, and carbon and nitrogen concentrations.Methods and Results: Tricalcium phosphate (CP) solubilization efficiency ofP. purpurogenum was evaluated at acid or alkaline pH using different C and Nsources. Glucose- and (NH4)2SO4-based media showed the highest P solubilizationvalues followed by fructose. P. purpurogenum solubilizing ability was higherin cultures grown at pH 6Æ5 than cultures at pH 8Æ5. Organic acids were detectedin both alkaline and neutral media, but the relative percentages of each organicacid differed. Highest P release coincided with the highest organic acids productionpeak, especially gluconic acid. When P. purpurogenum grew in alkalinemedia, the nature and concentration of organic acids changed at different N andC concentrations. A factorial categorical experimental design showed that thehighest P-solubilizing activity, coinciding with the highest organic acid production,corresponded to the highest C concentration and lowest N concentration.Conclusions: The results described in the present study show that medium pHand carbon and nitrogen concentrations modulate the P solubilization efficiencyof P. purpurogenum through the production of organic acids and particularlythat of gluconic acid. In the P solubilization optimization studies,glucose and (NH4)2SO4 as C and N sources allowed a higher solubilizationefficiency at high pH.Significance and Impact of the Study: This organism is a potentially proficientsoil inoculant, especially in P-poor alkaline soils where other P solubilizers failto release soluble P. Further work is necessary to elucidate whether these resultscan be extrapolated to natural soil ecosystems, where different pH values arepresent. Penicillium purpurogenum could be used to develop a bioprocess forthe manufacture of phosphatic fertilizer with phosphate calcium minerals.