Hexavalent chromium (Cr(VI)) is recognized to be carcinogenic and toxic and registered as a contaminant in many drinking water regulations. It occurs naturally and is also produced by industrial processes. The reduction of Cr(VI) to Cr(III) has been a central topic for chromium remediation since Cr(III) is less toxic and less mobile. In this study, fermentative Fe(III)-reducing bacterial strains (Cellu-2a, Cellu-5a, and Cellu-5b) were isolated from a groundwater sample and were phylogenetically related to species of Cellulomonas by 16S rRNA gene analysis. One selected strain, Cellu-2a showed its capacity of reduction of both soluble iron (ferric citrate) and solid iron (hydrous ferric oxide, HFO), as well as aqueous Cr(VI). The strain Cellu-2a was able to reduce 15 μM Cr(VI) directly with glucose or sucrose as a sole carbon source under the anaerobic condition and indirectly with one of the substrates and HFO in the same incubations. The heterogeneous reduction of Cr(VI) by the surface-associated reduced iron from HFO by Cellu-2a likely assisted the Cr(VI) reduction. Fermentative features such as large-scale cell growth may impose advantages on the application of bacterial Cr(VI) reduction over anaerobic respiratory reduction.

中文翻译：

---

发酵性 Fe(III) 还原纤维单胞菌属直接和间接还原 Cr(VI)。菌株 Cellu-2a。

六价铬 (Cr(VI)) 被认为具有致癌性和毒性，并在许多饮用水法规中被登记为污染物。它自然发生，也可以通过工业过程生产。将 Cr(VI) 还原为 Cr(III) 一直是铬修复的中心课题，因为 Cr(III) 毒性较低且流动性较低。在这项研究中，从地下水样品中分离出发酵性 Fe(III) 还原细菌菌株（Cellu-2a、Cellu-5a 和 Cellu-5b），并且在系统发育上与纤维单胞菌属相关通过16S rRNA基因分析。一种选定的菌株 Cellu-2a 显示出其还原可溶性铁（柠檬酸铁）和固体铁（水合氧化铁，HFO）以及水性 Cr(VI) 的能力。菌株 Cellu-2a 能够在厌氧条件下以葡萄糖或蔗糖作为唯一碳源直接还原 15 μM C​​r(VI)，并在相同的孵育条件下间接还原其中一种底物和 HFO。Cellu-2a 中来自 HFO 的表面相关还原铁对 Cr(VI) 的异质还原可能有助于 Cr(VI) 的还原。大规模细胞生长等发酵特征可能对细菌 Cr(VI) 还原的应用优于厌氧呼吸还原。