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在试验室通过使用多种碳源（包括醋酸盐、乳酸盐和葡萄糖），对采于朝鲜废弃金银矿地区的受砷污染的沉积物样品（339毫克／千克）中固有细菌生物激化后，就沉积物样品中固有细菌对砷物种形成和活动性的影响，进行了研究。通过连续提取分析来确定砷的形式，结果表明，沉积物中40％和47％的砷分别以铁伴生物和残留组分的形式存在。通过使用醋酸盐和乳酸盐对沉积物样品进行培育22天后，固有细菌增加了沉积物样品中铁伴生物和残留组分中溶解砷的总量。当与消过毒的沉积物样品（总溶解砷浓度低于50％）对比时发现，生物悬浮液中超过99％的溶解砷以砷（V）的形式存在，这表明，固有细菌将部分溶解的砷（III）转换成了砷（V）。在实际环境中，依据pH值的不同，微生物引起的水成砷（V）既可以通过吸附而固定不动，也可以在向地下缺氧区迁移后被还原成（III）。 相似文献
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When Pseudomonas aeruginosa PAO1 biofilms (attached to Sepharose surfaces) were subjected to dissolved Fe3+, most Fe was removed from solution within 25 h by surface complexation with negatively charged functional groups on the bacterial cell wall via a nucleation and mineralization process. Chemical formation of Fe-(hydr)oxides was partially responsible for dissolved Fe removal, which stemmed from a pH increase, facilitated by microbial activity. PAO1 used Fe3+ as an electron acceptor producing Fe2+ under localized anaerobic conditions over the first 50 h. The high ratio of Fe2+ to total Fe in solution produced a high proportion of Fe(II) in Fe precipitates; however, as the formation of Fe-(hydr)oxides started after 50 h, the Fe2+ content in solution began to diminish. Biofilms can so influence the local chemical conditions and metal speciation that the bulk solution phase is also affected, thereby mediating a wide-range (bio)geochemical cycling of iron. Long-term survival of natural biofilms, even under strict oligotrophic conditions, could have a broad lasting effect on the bulk geochemical environment. 相似文献
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