RAPID ASSAY FOR MICROBIALLY REDUCIBLE FERRIC IRON IN AQUATIC SEDIMENTS
RAPID ASSAY FOR MICROBIALLY REDUCIBLE FERRIC IRON IN AQUATIC SEDIMENTS
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DOI：
10.1128/aem.53.7.1536-1540.1987
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发表时间：
1987-07-01
影响因子：
4.4
通讯作者：
PHILLIPS, EJP
中科院分区：
文献类型：
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作者：
LOVLEY, DR;PHILLIPS, EJP
由铁还原生物活性直接确定的微生物还原铁的有效性与由新开发的微生物还原铁化学测定法确定的铁的有效性进行了比较。化学分析是基于在酸性条件下羟胺对低结晶铁的还原。在铁还原生物的富集培养中，羟胺可以减少各种合成铁形式的程度与铁对微生物还原的敏感性之间存在很强的相关性。当含有羟胺可还原铁的沉积物在厌氧条件下孵育时，亚铁随着羟胺可还原铁的浓度随时间下降而积累。一旦羟胺还原铁耗尽，亚铁的生产就停止了。在不含羟胺可还原铁的还原沉积物厌氧培养中，即使沉积物中含有高浓度的草酸盐可提取的铁，也没有微生物铁还原。在来自含水层的沉积物和来自波托马克河河口的淡水和微咸水沉积物中，观察到厌氧培养中羟胺可还原铁的存在与铁的还原程度之间的对应关系。该测定法对先前描述的测定羟胺还原性铁的方法进行了重大改进，因为它对高浓度的固体铁（也可以用酸从沉积物中提取）提供了校正。这是一种快速、简单的技术，可以确定铁是否可用于微生物还原。
The availability of ferric iron for microbial reduction as directly determined by the activity of iron-reducing organisms was compared with its availability as determined by a newly developed chemical assay for microbially reducible iron. The chemical assay was based on the reduction of poorly crystalline ferric iron by hydroxylamine under acidic conditions. There was a strong correlation between the extent to which hydroxylamine could reduce various synthetic ferric iron forms and the susceptibility of the iron to microbial reduction in an enrichment culture of iron-reducing organsims. When sediments that contained hydroxylamine-reducible ferric iron were incubated under anaerobic conditions, ferrous iron accumulated as the concentration of hydroxylamine-reducible ferric iron declined over time. Ferrous iron production stopped as soon as the hydroxylamine-reducible ferric iron was depleted. In anaerobic incubations of reduced sediments that did not contain hydroxylamine-reducible ferric iron, there was no microbial iron reduction, even though the sediments contained high concentrations of oxalate-extractable ferric iron. A correspondence between the presence of hydroxylamine-reducible ferric iron and the extent of ferric iron reduction in anaerobic incubations was observed in sediments from an aquifer and in fresh- and brackish-water sediments from the Potomac River estuary. The assay in a significant improvement over previously described procedures for the determination of hydroxylamine-reducible ferric iron because it provides a correction for the high concentrations of solid ferrous iron which may also be extracted from sediments with acid. This is a rapid, simple technique to determine whether ferric iron is available for microbial reduction.