Characterization of the mineral phosphate-solubilizing activity of pantoea aglomerans MMB051 isolated from an Iron-Rich soil in southeastern Venezuela (Bolívar State)
Resumen
The mineral phosphate-solubilizing (MPS)
activity of a Pantoea agglomerans strain, namely
MMB051, isolated from an iron-rich, acidic soil near
Ciudad Piar (Bolý´var State, Venezuela), was characterized
on a chemically defined medium (NBRIP). Various insoluble
inorganic phosphates, including tri-calcium phosphate
[Ca3(PO4)2], iron phosphate (FePO4), aluminum phosphate
(AlPO4), and Rock Phosphate (RP) were tested as sole
sources of P for bacterial growth. Solubilization of
Ca3(PO4)2 was very efficient and depended on acidification
of the external milieu when MMB051 cells were grown in
the presence of glucose. This was also the case when RP
was used as the sole P source. On the other hand, the
solubilization efficiency toward more insoluble mineral
phosphates (FePO4 and AlPO4) was shown to be very low.
Even though gluconic acid (GA) was detected on culture
supernatants of strain MMB051, a consequence of the
direct oxidation pathway of glucose, inorganic-P solubilization
seemed also to be related to other processes
dependent on active cell growth. Among these, proton
release by ammonium (NH4) fixation appeared to be of
paramount importance to explain inorganic-P solubilization
mediated by strain MMB051. On the contrary, the
presence of nitrate (NO3) salts as the sole N source affected
negatively the ability of MMB051 cells to solubilize
inorganic P.
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Correo Electrónico | elimariana@ula.ve, sheyla88@yahoo.com mball@ula.ve yluis@ula.ve bahsas@ula.ve |
Editor | Current Microbiology 2009 Apr;58(4):378-83 |
Citación | DOI 10.1007/s00284-008-9327-1 |