Microorganisms and microbial products can be highly efficient bioaccumulators of soluble and particulate forms of metals, especially from dilute external solutions, and microbe-related technologies may provide an alternative or adjunct to conventional techniques of metal removal/recovery. In this work, among microorganisms isolated from wastewater treatment of a petrochemical industry, a gram-negative bacterium Pantoea sp. TEM 18 exhibited the greatest copper tolerance. It was able to survive in the medium containing copper at concentrations as high as 180 mg/l. The biosorption properties of bacterial biomass for cadmium and the effects of environmental factors (i.e. pH, metal concentration contact time) on the chromium, cadmium and copper biosorption were explored. Optimum adsorption pH values of chromium(VI), cadmium(II) and copper(II) were determined as 3.0, 6.0 and 5.0, respectively. Experimental results also showed the influence of initial metal concentration on the metal uptake for dried biomass. Both the Freundlich and Langmuir adsorption models were suitable for describing the short-term biosorption of chromium(VI), cadmium(II) and copper(II) by Pantoea sp. TEM 18. (C) 2004 Elsevier B.V. All rights reserved.

WOS: 000223840100005