title: Characterization of the mineral phosphate-solubilizing activity of Pantoea agglomerans MMB051 isolated from an iron-rich soil in southeastern Venezuela (Bolívar State).
abstract: The mineral phosphate-solubilizing (MPS) activity of a Pantoea agglomerans strain, namely MMB051, isolated from an iron-rich, acidic soil near Ciudad Piar (Bolívar State, Venezuela), was characterized on a chemically defined medium (NBRIP). Various insoluble inorganic phosphates, including tri-calcium phosphate [Ca(3)(PO(4))(2)], iron phosphate (FePO(4)), aluminum phosphate (AlPO(4)), and Rock Phosphate (RP) were tested as sole sources of P for bacterial growth. Solubilization of Ca(3)(PO(4))(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 (FePO(4) and AlPO(4)) 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 (NH(4)(+) ) fixation appeared to be of paramount importance to explain inorganic-P solubilization mediated by strain MMB051. On the contrary, the presence of nitrate (NO(3)(-) ) salts as the sole N source affected negatively the ability of MMB051 cells to solubilize inorganic P.
authors.affiliation: Laboratorio de Microbiología Molecular y Biotecnología, Facultad de Ciencias, Núcleo de La Hechicera, Universidad de Los Andes, Mérida 5101, Venezuela.
authors.forename: Miguel
authors.initials: M
authors.lastname: Sulbarán
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Pérez
authors.forename: María M
authors.initials: MM
authors.lastname: Ball
authors.forename: Alí
authors.initials: A
authors.lastname: Bahsas
authors.forename: Luis Andrés
authors.initials: LA
authors.lastname: Yarzábal
mesh_terms: D002130:Calcium Phosphates / Q000378:metabolism; D003470:Culture Media; D019015:Geologic Sediments / Q000382:microbiology*; D007501:Iron / Q000737:chemistry; D008903:Minerals / Q000378:metabolism*; D020636:Pantoea / Q000302:isolation & purification / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology; D012995:Solubility; D014687:Venezuela
chemical_list: D002130:Calcium Phosphates; D003470:Culture Media; D008903:Minerals; D010710:Phosphates; D012987:Soil; C020243:calcium phosphate; D007501:Iron