Removal of soluble copper by exopolysaccharide isolated from copper-resistant bacterial isolates

Abstract

Two strains of 350 strains of copper-resistant bacterial isolates were selected and named CuR-38 and CuR-40. Both of them resisted to 700 µg/ml Cu and EPS-producing. By some identification test, they might be classified as Zoogloea sp. and Bacillus sp., respectively. Optimum pH and temperature for growth and EPS production were 7 and 37°c. EPS production appeared maximally during the stationary phase (48 hr.). Addition of Cu induction was not induced EPS production in both bacterial isolates. The copper accumulation capacities between wet EPS and wet whole cell is highest, but not much different. The percentage of Cu accumulation by dried EPS was greater than 80% of both strains. The dried EPS has been used to remove other metal (zinc, manganese and cadmium). The release of metal from EPS achieved by HC1 and can regenerated to reuse in the future.