Diversity of sulfur isotope fractionations by sulfate-reducing prokaryotes
Diversity of sulfur isotope fractionations by sulfate-reducing prokaryotes
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DOI：
10.1128/aem.67.2.888-894.2001
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发表时间：
2001-02-01
影响因子：
4.4
通讯作者：
Kuever, J
中科院分区：
文献类型：
--
作者：
Detmers, J;Br端chert, V;Kuever, J
对32种硫酸盐还原原核生物进行了批量培养实验，探讨了纯培养硫酸盐异化还原过程中硫同位素分馏的多样性。所选菌株反映了目前已知硫酸盐还原剂的系统发育和生理多样性，覆盖了广泛的自然海洋和淡水栖息地。实验条件为电子给体、盐度、温度和ph的最佳生长条件。在此条件下，实验分馏因子范围为2.0 ~ 42.0 ppm。盐度、孵育温度、pH和系统发育对硫同位素分馏没有系统影响，同位素分馏与硫酸盐还原速率没有相关性。异化亚硫酸氢盐还原酶的类型对分馏也没有影响，将碳源完全氧化为CO的硫酸盐还原剂比释放醋酸盐作为碳氧化的最终产物的硫酸盐还原剂分馏更大。不同的代谢途径和硫酸盐跨细胞膜运输的可变调节都可能影响同位素分异。以前的模型只根据硫酸盐还原速率来解释分馏，这似乎过于简化了。因此，需要考虑每种硫酸盐还原剂的物种特异性生理，以了解异化硫酸盐还原过程中硫同位素分馏的调节。
Batch culture experiments were performed with 32 different sulfate-reducing prokaryotes to explore the diversity in sulfur isotope fractionation during dissimilatory sulfate reduction by pure cultures. The selected strains reflect the phylogenetic and physiologic diversity of presently known sulfate reducers and cover a broad range of natural marine and freshwater habitats. Experimental conditions were designed to achieve optimum growth conditions with respect to electron donors, salinity, temperature, and pH. Under these optimized conditions, experimental fractionation factors ranged from 2.0 to 42.0 parts per thousand. Salinity, incubation temperature, pH, and phylogeny had no systematic effect on the sulfur isotope fractionation, There was no correlation between isotope fractionation and sulfate reduction rate. The type of dissimilatory bisulfite reductase also had no effect on fractionation, Sulfate reducers that oxidized the carbon source completely to CO, showed greater fractionations than sulfate reducers that released acetate as the final product of carbon oxidation. Different metabolic pathways and variable regulation of sulfate transport across the cell membrane all potentially affect isotope fractionation. Previous models that explained fractionation only in terms of sulfate reduction rates appear to be oversimplified. The species-specific physiology of each sulfate reducer thus needs to be taken into account to understand the regulation of sulfur isotope fractionation during dissimilatory sulfate reduction.