title: Biosorption of metal ions byAzotobacter vinelandii.
abstract: Azotobacter vinelandii was better than eitherDerxia gummosa orRhizobium trifolii for sorption of UO 2 (2+) . Its maximum binding capacity was 0.25 mmol UO 2 (2+) /g dry biomass with an affinity constant of 333 l/mmol at pH 4.1 according to the Langmuir model. In a semisynthetic medium,A. vinelandii showed the highest sorption capacity in the early stationary phase. The binding of UO 2 (2+) , Cu(2+), Ca(2+) and Zn(2+) was affected by the pH of the solution. With HCl as eluent, virtually all the sorbed UO 2 (2+) was released. The presence of Cu(2+), Cd(2+), Ca(2+), and Zn(2+) inhibited the UO 2 (2+) biosorption whereas Mg(2+) and K(+) had no effect.
authors.affiliation: Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Quimicas y Farmacéuticas, Universidad de Chile, Casilla 233, Santiago 1, Chile.
authors.forename: D
authors.initials: D
authors.lastname: Cotoras
authors.forename: M
authors.initials: M
authors.lastname: Millar
authors.forename: P
authors.initials: P
authors.lastname: Viedma
authors.forename: J
authors.initials: J
authors.lastname: Pimentel
authors.forename: A
authors.initials: A
authors.lastname: Mestre