A Bacillus subtilis strain can reduce hexavalent chromium to trivalent and an nfrA gene is involved

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• 责任者：Zhe Zheng1 ; ; Yabo Li1 ; ; Xiaowei Zhang ; Pu Liu ; Jun Ren ; Gaofeng Wu ; Yanli Zhang ; Yong Chen ; Xiangkai Li
• 主题词：Bacillus ; Bioremediation ; nfrA ; Chromium ; Rare-earth ore
• 年：2015
• 作者单位：Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshuinanlu #222, Lanzhou, Gansu 730000, PR China
• 刊：International Biodeterioration & Biodegradation
• 期：97

摘要

Baiyin city, which is located upstream of the Yellow River and in the central part of Gansu province, China, is severely contaminated by heavy metals such as chromium. A Gram-positive bacterium BYCr-1 capable of reducing hexavalent chromium (Cr(VI)) to trivalent (Cr(III)) aerobically was isolated from a rare-earth ore in Baiyin, Gansu, China. 16S rRNA analysis revealed that it was closely related to Bacillus subtilis. It can reduce 0.2 mM Cr(VI) to Cr(III) in M9 medium after 48 h incubation. Transmission electron microscopy (TEM) image showed that Cr(III) precipitates were located both inside and outside the cells. An nfrA gene was upregulated by 5.3 folds upon Cr(VI) treatment. Furthermore, E. coli-NfrA demonstrated elevated chromate-reducing ability. Our results indicate that BYCr-1 is able to resist and reduce high concentrations of Cr(VI), which makes it a potentially suitable candidate for bioremediation of Cr(VI) contamination. This study also reveals that nfrA confers Cr(VI)-reducing ability in Bacillus subtilis.