title: Coexpression of the pyrroloquinoline quinone and glucose dehydrogenase genes from Serratia marcescens CTM 50650 conferred high mineral phosphate-solubilizing ability to Escherichia coli.
abstract: The genes gdh and pqqABCDE encoding glucose dehydrogenase and its pyrroloquinoline quinone cofactor were cloned from the mineral phosphate-solubilizing (MPS) bacterium Serratia marcescens CTM 50650. We investigated, for the first time, the impact of their coexpression in Escherichia coli on MPS ability. The production of recombinant PQQGDH conferred high MPS activity to the engineered E. coli. In fact, the amounts of soluble phosphorus (P) produced from tricalcium phosphate, hydroxyapatite, and Gafsa rock phosphate (GRP) were 574, 426, and 217 mg/L, respectively. In an attempt to increase the soluble P concentration, the E. coli strain coexpressing the gdh and pqqABCDE genes was immobilized in agar, calcium alginate, and k-carrageenan and was then further applied in a repeated batch (six batches) fermentation process to solubilize GRP. Compared to other encapsulated systems, alginate cell beads were noted to yield the highest concentration of soluble P, which attained 300 mg/L/batch. MPS efficiency was maximal in the presence of 5 and 40 g/L of GRP and glucose, respectively.
authors.affiliation: Laboratoire de Microorganismes et de Biomolécules, Centre de Biotechnologie de Sfax, Université 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: Amin
authors.initials: A
authors.lastname: Fourati
authors.forename: Hichem
authors.initials: H
authors.lastname: Chouayekh
mesh_terms: D004926:Escherichia coli / Q000502:physiology*; D024861:Genetic Enhancement / Q000379:methods*; D042843:Glucose 1-Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D045542:PQQ Cofactor / Q000378:metabolism*; D010710:Phosphates / Q000737:chemistry / Q000378:metabolism*; D015202:Protein Engineering / Q000379:methods; D011994:Recombinant Proteins / Q000378:metabolism*; D012706:Serratia marcescens / Q000502:physiology*; D012995:Solubility
chemical_list: D010710:Phosphates; D011994:Recombinant Proteins; D045542:PQQ Cofactor; D042843:Glucose 1-Dehydrogenase