Hexavalent chromium is one of the most widely distributed environmental contaminants. Given the carcinogenic and mutagenic consequences of Cr(VI) exposure, the release of Cr(VI) into the environment has long been a major concern. While many reports of microbial Cr(VI) reduction are in circulation, very few have demonstrated Cr(VI) reduction under alkaline conditions. Since Cr(VI) exhibits higher mobility in alkaline soils relative to pH neutral soils, and since Cr contamination of alkaline soils is associated with a number of industrial activities, microbial Cr(VI) reduction under alkaline conditions requires attention.Soda lakes are the most stable alkaline environments on earth, and contain a wide diversity of alkaliphilic organisms. In this study, a bacterial isolate belonging to the Halomonas genus was obtained from Soap Lake, a chemically stratified alkaline lake located in central Washington State. The ability of this isolate to reduce Cr(VI) and Fe(III) was assessed under alkaline (pH = 9), anoxic, non-growth conditions with acetate as an electron donor. Metal reduction rates were quantified using Monod kinetics. In addition, Cr(VI) reduction experiments were carried out in the presence of Fe(III) to evaluate the possible enhancement of Cr(VI) reduction rates through electron shuttling mechanisms. While Fe(III) reduction rates were slow compared to previously reported rates, Cr(VI) reduction rates fell within range of previously reported rates.

中文翻译：

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Fe（III），Cr（VI）和Fe（III）使用从华盛顿州Soap Lake分离的卤单胞菌在碱性介质中介导的Cr（VI）还原。

六价铬是分布最广泛的环境污染物之一。考虑到Cr（VI）暴露的致癌和诱变后果，向环境中释放Cr（VI）一直是一个主要问题。尽管有许多关于微生物体内六价铬还原的报道，但很少有人在碱性条件下证明六价铬还原。由于相对于pH中性土壤，Cr（VI）在碱性土壤中表现出更高的迁移率，并且由于碱性土壤中的Cr污染与许多工业活动有关，因此在碱性条件下微生物对Cr（VI）的还原需要引起关注。地球上具有稳定的碱性环境，并且包含多种多样的嗜碱生物。在这项研究中，从Soap Lake获得了一种属于Halomonas属的细菌分离株，位于华盛顿州中部的化学分层碱性湖。在碱性（pH = 9），缺氧，无生长条件下，以乙酸盐作为电子给体，评估了该分离物还原Cr（VI）和Fe（III）的能力。金属还原速率使用Monod动力学进行定量。此外，在Fe（III）存在下进行了Cr（VI）还原实验，以评估通过电子穿梭机制可能提高的Cr（VI）还原速率。尽管Fe（III）的还原速率比以前报告的速率慢，但是Cr（VI）的还原速率却在先前报告的速率范围内。金属还原速率使用Monod动力学进行定量。此外，在Fe（III）存在下进行了Cr（VI）还原实验，以评估通过电子穿梭机制可能提高的Cr（VI）还原速率。尽管Fe（III）的还原速率比以前报告的速率慢，但是Cr（VI）的还原速率却在先前报告的速率范围内。金属还原速率使用Monod动力学进行定量。此外，在Fe（III）存在下进行了Cr（VI）还原实验，以评估通过电子穿梭机制可能提高的Cr（VI）还原速率。尽管Fe（III）的还原速率比以前报告的速率慢，但是Cr（VI）的还原速率却在先前报告的速率范围内。