title: Evaluation of chromate reductase activity in the cell-free culture filtrate of Arthrobacter sp. SUK 1201 isolated from chromite mine overburden.
abstract: Arthrobacter sp. SUK 1201, a chromate resistant and reducing bacterium isolated from chromite mine overburden of Sukinda valley, Odisha, India has been evaluated for its hexavalent chromium [Cr(VI)] reduction potential using cell-free culture filtrate as extracellular chromate reductase enzyme. Production of the enzyme was enhanced in presence of Cr(VI) and its reducing efficiency was increased with increasing concentration of Cr(VI). The Michaelis-Menten constant (Km) and the maximum specific velocity (Vmax) of the extracellular Cr(VI) reductase were calculated to be 54.03 μM Cr(VI) and 5.803 U mg(-1) of protein respectively showing high affinity towards Cr(VI). The reducing activity of the enzyme was maximum at pH 6.5-7.5 and at a temperature of 35 °C and was dependent on NADH. The enzyme was tolerant to different metals such as Mn(II), Mg(II) and Fe(III) and was able to reduce Cr(VI) present in chromite mine seepage. These findings suggest that the extracellular chromate reductase of Arthrobacter sp. SUK 1201 has a great promise for use in Cr(VI) detoxification under different environmental conditions, particularly in the mining waste water treatment systems.
authors.affiliation: Microbiology Laboratory, Department of Botany, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700 019, India. Electronic address: dey1919@gmail.com.
authors.forename: Satarupa
authors.initials: S
authors.lastname: Dey
authors.affiliation: Microbiology Laboratory, Department of Botany, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700 019, India. Electronic address: amalk_paul@yahoo.co.in.
authors.forename: A K
authors.initials: AK
authors.lastname: Paul
mesh_terms: D001173:Arthrobacter / Q000201:enzymology*; D001673:Biodegradation, Environmental; D002857:Chromium / Q000737:chemistry* / Q000378:metabolism; D005290:Ferric Compounds; D005374:Filtration; D007194:India; D007220:Industrial Waste; D008670:Metals / Q000737:chemistry / Q000378:metabolism; D008906:Mining; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D013696:Temperature
chemical_list: D005290:Ferric Compounds; D007220:Industrial Waste; D008670:Metals; D002857:Chromium; C074702:chromium hexavalent ion; D010088:Oxidoreductases; C063243:chromate reductase
keywords: Arthrobacter; Cell-free culture filtrate; Chromite mine overburden; Chromium bioremediation; Extracellular chromate reductase; Mining waste water