AN INTEGRATED APPROACH FOR SAFE REMOVAL OF CHROMIUM (VI) BY BREVIBACTERIUM SP.

Abstract

Chromium (VI) tolerant Brevibacterium sp. AKR2 was isolated from the tannery effluent polluted site and consequently screened for chromate removal potential and exopolymer production. This strain showed stable growth with white-gray colonies on LB-agar plates supplemented with chromate (1500mg/L). Strain AKR2 was taxonomically identified by 16S rRNA sequencing as Brevibacterium sp. (MN932133). Presumptive biochemical tests were also performed. This strain was found to have multiple heavy metals and antibiotic tolerance patterns. Additionally, the tolerance profile of Brevibacterium sp. against Cr(VI) (2-30mg/mL) was investigated. Cr(VI) reduction ability at 1000 and 1500mg/L of K2CrO4 highlighted that the strain AKR2 reduced 91 and 86% of chromate oxyanions, respectively, after 24h of incubation. Enhanced exopolymer i.e. 1.275mg/mL dry weight was observed by growing in LB-broth medium under chromate stress conditions 1500mg/L as compared to EPS yield under non-stress 0.15mg/mL. Hence, the current investigation suggests the possible use of chromate resistant Brevibacterium sp. as an emerging tool for remediating the sites polluted with elevated levels of Cr(VI).