Biosorption of Copper by Paenibacillus polymyxa Cells and their Exopolysaccharide

• DOI: 10.1007/s11274-005-0381-6
• Publication Date: 2005-11-17T14:39:01Z
• Authors: M. Prado Acosta; E. Valdman; S. G. F. Leite; F. Battaglini; S. M. Ruzal
• Keywords: Biosorption; Paenibacillus polymyxa; Langmuir adsorption model

Biosorption of heavy metals by gram-positive, non-pathogenic and non-toxicogenic Paenibacillus polymyxa P13 was evaluated. Copper was chosen as a model element because it is a pollutant originated from several industries. An EPS (exopolysaccharide)-producing phenotype exhibited significant Cu(II) biosorption capacity. Under optimal assay conditions (pH 6 and 25 °C), the adsorption isotherm for Cu(II) in aqueous solutions obeyed the Langmuir model. A high q value (biosorption capacity) was observed with whole cells (qmax=112 mgCu g−1). EPS production was associated with hyperosmotic stress by high salt (1 M NaCl), which led to a significant increase in the biosorption capacity of whole cells (qmax=150 mgCu g−1). Biosorption capacity for Cu(II) of the purified EPS was investigated. The maximum biosorption value (q) of 1602 mg g−1 observed with purified EPS at 0.1 mg ml−1 was particularly promising for use in field applications.