title: Characterization of the mineral phosphate solubilizing activity of Serratia marcescens CTM 50650 isolated from the phosphate mine of Gafsa.
abstract: The mineral phosphate solubilizing (MPS) ability of a Serratia marcescens strain, namely CTM 50650, isolated from the phosphate mine of Gafsa, was characterized on a chemically defined medium (NBRIP broth). Various insoluble inorganic phosphates, including rock phosphate (RP), calcium phosphate (CaHPO(4)), tri-calcium phosphate (Ca(3)(PO(4))(2)) and hydroxyapatite were tested as sole sources of phosphate for bacterial growth. Solubilization of these phosphates by S. marcescens CTM 50650 was very efficient. Indeed, under optimal conditions, the soluble phosphorus (P) concentration it produced reached 967, 500, 595 and 326 mg/l from CaHPO(4), Ca(3)(PO(4))(2), hydroxyapatite and RP, respectively. Study of the mechanisms involved in the MPS activity of CTM 50650, showed that phosphate solubilization was concomitant with significant drop in pH. HPLC-analysis of culture supernatants revealed the secretion of gluconic acid (GA) resulting from direct oxidation pathway of glucose when the CTM 50650 cells were grown on NBRIP containing glucose as unique carbon source. This was correlated with the simultaneous detection by PCR for the first time in a S. marcescens strain producing GA, of a gene encoding glucose dehydrogenase responsible for GA production, as well as the genes pqqA, B, C and E involved in biosynthesis of its PQQ cofactor. This study is expected to lead to the development of an environmental-friendly process for fertilizer production considering the capacity of S. marcescens CTM 50650 to achieve yields of P extraction up to 75% from the Gafsa RP.
authors.affiliation: Laboratoire d'Enzymes et de Métabolites des Procaryotes (LEMP), Centre de Biotechnologie de Sfax, Route de Sidi Mansour Km 6, BP "1177", 3018 Sfax, Tunisia.
authors.forename: Mounira
authors.initials: M
authors.lastname: Ben Farhat
authors.forename: Ameny
authors.initials: A
authors.lastname: Farhat
authors.forename: Wacim
authors.initials: W
authors.lastname: Bejar
authors.forename: Radhouan
authors.initials: R
authors.lastname: Kammoun
authors.forename: Kameleddine
authors.initials: K
authors.lastname: Bouchaala
authors.forename: Amin
authors.initials: A
authors.lastname: Fourati
authors.forename: Hani
authors.initials: H
authors.lastname: Antoun
authors.forename: Samir
authors.initials: S
authors.lastname: Bejar
authors.forename: Hichem
authors.initials: H
authors.lastname: Chouayekh
mesh_terms: D002130:Calcium Phosphates / Q000378:metabolism*; D003470:Culture Media; D004269:DNA, Bacterial / Q000235:genetics; D017886:Durapatite / Q000378:metabolism*; D005798:Genes, Bacterial; D019015:Geologic Sediments; D005942:Gluconates / Q000378:metabolism; D042843:Glucose 1-Dehydrogenase / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008906:Mining; D045542:PQQ Cofactor / Q000235:genetics / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism*; D012706:Serratia marcescens / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012988:Soil Microbiology; D012995:Solubility; D014416:Tunisia
chemical_list: D002130:Calcium Phosphates; D003470:Culture Media; D004269:DNA, Bacterial; D005942:Gluconates; D010710:Phosphates; D045542:PQQ Cofactor; D017886:Durapatite; D042843:Glucose 1-Dehydrogenase; C030691:gluconic acid