INFLUENCE OF SODIUM ON ASSIMILATION PROCESS OF Cr(VI) AND Cu BY ARTHROBACTER GLOBIFORMIS 151B CHROMIUM-RESISTANT BACTERIUM

Abstract

The process of assimilation of Cr(VI) and Cu by chromium-resistant bacteria ( Arthrobacter globiformis 151B) and the influence of high-concentration Na ions on this process have been studied. The bacteria are known for their property to assimilate the hexavalent chromium ions from the environment intensively, to convert them into trivalent form and to accumulate it in the cell. Thanks to these properties, it is possible to use them for detoxification of the environment , polluted by highly toxic Cr(VI). The strain of bacteria under investigation was isolated from basalt samples taken from the places highly contaminated by Cr(VI) in Kazreti. The solutions of the studied elements (Cr and Cu) and Na were introduced simultaneously into the nutrient medium. We studied the influence of different concentrations of Na ions during a different period of time of bacteria cultivation (17h, 24 h, 48 h, 96 h and 144 hours) on the process of assimilation of Cr and Cu by bacteria. The concentration of Na in the nutrient medium was 2, 3.5, 6.5 and 9.5 g mL -1 . For determination of the content of metals (Cr, Cu, and Na) in the cell, after the cultivation of bacteria, the precipitation of cells by centrifuge and the preparation of the obtained bacterial pellet for the analysis were carried out. The content of metals was measured by atom-absorption spectrometry.