Novel chromium tolerant microorganisms: Isolation, characterization and their biosorption capacity

Effluent from tannery, electroplating and electronic industries contain chromium which is highly toxic. This paper reports isolation of chromium tolerant microorganisms from solid waste as well as liquid effluent of an electroplating industry. Nine isolates were obtained that can tolerate chromium concentration up to 700 mg/L. They reach their stationary phase within 8-12 h and can biosorb 95% of initial 200 mg/L concentration of chromium within 4-10 h. Fourier Transform Infra Red analysis of the biomass exposed to chromium indicates that amino and carboxylate groups in the biomass are involved in biosorption process. 16S RNA results of two most active organisms indicate that they are Bacillus marisflavi and Arthrobacter sp. and they show 98% and 96% homology similarity in the phylogenetic tree, respectively. © 2007 Elsevier Inc. All rights reserved.