Abstract
The effect of different organic carbon sources on Cr(VI) reduction by Bacillus sp. was investigated. Three organic compounds, malate, succinate and glucose were tested in Cr(VI) reduction experiments. The results demonstrated that three organic compounds all significantly enhanced Cr(VI) reduction. The enhancing degree of these three organic compounds was observed as malate>glucose>succinate, although the cell growth in succinate-added medium was similar to that in malate-added medium and was apparently higher than that in glucose-added medium. Addition of glucose resulted in decrease of pH and increase of redox potential, while addition of malate or succinate resulted in increase of pH and decrease of redox potential during Cr(VI) reduction. Cr(VI) was reduced by liquid culture metabolite when glucose was added in liquid medium, but not reduced by liquid culture metabolite when malate or succinate was applied in liquid medium for bacterial cultivation.