微生物砷代谢机制的研究进展（Progress in Study of Mechanisms of Microbial Arsenic Transformation in Environment）

环境砷污染是一个全球性问题.研究砷的生物地球化学循环可以明确环境中砷的来源及其转化特征,为探索砷污染治理的方法提供参考.越来越多的研究表明,自然界中的微生物在砷的迁移转化过程中发挥了重要作用.根据微生物对砷的代谢机制不同将其分为:砷氧化微生物、砷还原微生物和砷甲基化微生物.砷氧化微生物可以将环境中的As(Ⅲ)氧化为毒性较弱并且容易被铁铝矿物吸附固定的As(Ⅴ),因此对降低环境中的砷毒性具有重要作用;微生物对砷的甲基化作用的产物通常为毒性较低的有机砷,因此也被认为是理想的修复环境砷污染的生物手段之一;然而在还原环境中,砷还原微生物却可以将游离态和结合态的As(Ⅴ)还原为毒性更强的As(Ⅲ),从而加重环境中的砷污染状况.由此可见,明确微生物的砷代谢机制及其对砷污染环境中砷迁移转化的影响,是实现生物修复砷污染环境的必要前提.论文总结了近年来国内外微生物砷代谢机制的研究进展,以期为深入研究微生物代谢砷的机理及其在砷污染治理中的应用提供参考.

Progress in Study of Mechanisms of Microbial Arsenic Transformation in Environment

Arsenic (As) is an ubiquitous contamination, microbes can live in As -contaminated environments and play an important role in it’s transformation. Microbial As oxidization is viewed as a detoxification reaction that converts As (Ⅲ) into the less toxic form, As (Ⅴ), perhaps making it more likely to be absorbed to mineral surface. However microbial As (Ⅴ)reduction may take place in anaerobic environments with the absence of oxygen, and can contribute to As mobilization from the solid to the aqueous phase. Furthermore, microbial methylation of As can convert inorganic specis to soluble or volatile methylated compounds which are much less toxic than the former, therefore these microorganisms have an obvious potential for bioremediation/biomitigation. This review highlights recent studies in the mechanisms of microbial transformation of arsenic in order to provide useful information for the development of remediation strategies and technologies for As-contaminated environments.