eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2016-05-06 7 2 963 967 9588 article V. Mishra 1 D.P. Samantaray 1 S.K. Dash 1 A.K. Sethi 1 And B.B. Mishra 1 Post Graduate Department of Microbiology, Centre for Post Graduate Studies Orissa University of Agriculture and Technology, Bhubaneswar - 751 003 (India). Rapid industrialization and development of chemical and mining industries in Sukinda mining area, district of Jajpur, Orissa has drawn worldwide attention as one of the most polluted area with hexavalent chromium due to chromite rich. It is pertinent mention that hexavalent chromium is highly toxic to living beings including the flora & fauna around Sukinda mining area. On account of that, an attempt has been made in the present investigation to detoxify Cr(VI) by employing a lyophilized Gram-negative bacteria i.e. A. calcoaciticus isolated from that area. It was observed that A. calcoaceticus tolerated 1000ppm of hexavalent chromium. It shown 78.03% hexavalent chromium reduction when incubated in a nutritive medium at 30°C for 24 hours at pH 7 and the rate of reduction decreased from 78.03 to 38.1% in a nonnutritive medium. Then the bacteria was selected for parametric studies and observed to exhibit highest reduction 85% at pH 8.0, temperature 30/ 24 hours. Therefore, A. calcoaceticus may be used for bioremediation of hexavalent chromium toxicity in different chromium contaminated sites. https://www.biotech-asia.org/vol7no2/aerobic-hexavalent-chromium-reduction-by-acenetobacter-calcoaciticus/ Bioremediation; Hexavalent chromium; lyophilized; Nutritive medium