Elimination du chrome (VI) par Bacillus mégathérium, un hyperaccumulateur isolé de la boue activée de la tannerie de Jijel

Abstract

Cr(III) is used in tannery processing and when left untreated, it is converted to its toxic form Cr(VI), due to oxidation. The toxic hexavalent chromium Cr(VI) is known to be carcinogenic and mutagenic. Several bacteria possess the capability to reduce Cr(VI), to accumulate it or to adsorb it, so bioremediation gives immense opportunities for the developmeot of technologies to detoxify Cr(VI)-contaminated soils or water as an alternative to the existing physicochemical technologies. The aim of the work was to evaluate the ability of Baci/lus megaterium (A3-1) to resist the Cr (VI), by determining the MIC, on the one band, and secondly to study the various Cr (Vl) removal mechanisms, including enzymatic reduction and bioaccumulation. Our results indicated that, Bacillus megaterium (A3-1) exhibited an MIC for Cr (VI) of 80 mg/L, and could reduce chromate to 1 OO % at a concentration of 30 mg/L after 72 h at 37 °C, furthermore, the rates of Cr (VI) accumulation were 27,50 mg/g dry weight for 30 mg Cr (VI)/L.