PDF(Pubmed)
Abstract：
Anaerobic microbial corrosion of iron-containing metals causes extensive economic damage. Some microbes are capable of direct metal-to-microbe electron transfer (electrobiocorrosion), but the prevalence of electrobiocorrosion among diverse methanogens and acetogens is poorly understood because of a lack of tools for their genetic manipulation. Previous studies have suggested that respiration with 316L stainless steel as the electron donor is indicative of electrobiocorrosion, because, unlike pure Fe0, 316L stainless steel does not abiotically generate H2 as an intermediary electron carrier. Here, we report that all of the methanogens (Methanosarcina vacuolata, Methanothrix soehngenii, and Methanobacterium strain IM1) and acetogens (Sporomusa ovata and Clostridium ljungdahlii) evaluated respired with pure Fe0 as the electron donor, but only M. vacuolata, Mx. soehngenii, and S. ovata were capable of stainless steel electrobiocorrosion. The electrobiocorrosive methanogens required acetate as an additional energy source in order to produce methane from stainless steel. Cocultures of S. ovata and Mx. soehngenii demonstrated how acetogens can provide acetate to methanogens during corrosion. Not only was Methanobacterium strain IM1 not capable of electrobiocorrosion, but it also did not accept electrons from Geobacter metallireducens, an effective electron-donating partner for direct interspecies electron transfer to all methanogens that can directly accept electrons from Fe0. The finding that M. vacuolata, Mx. soehngenii, and S. ovata are capable of electrobiocorrosion, despite a lack of the outer-surface c-type cytochromes previously found to be important in other electrobiocorrosive microbes, demonstrates that there are multiple microbial strategies for making electrical contact with Fe0.
摘要：
含铁金属的厌氧微生物腐蚀造成广泛的经济损失。一些微生物能够直接进行金属到微生物的电子转移（电生物腐蚀），但是，由于缺乏遗传操作工具，人们对各种产甲烷菌和产乙酸菌中的电生物腐蚀的普遍性知之甚少。以前的研究表明，以316L不锈钢作为电子供体的呼吸作用表明了电生物腐蚀，因为,与纯Fe0不同，316L不锈钢不会产生作为中间电子载体的H2。这里,我们报道了所有的产甲烷菌(甲烷空泡，Methanothrixsoehngenii,和甲烷杆菌菌株IM1）和乙酸原（Sporomusaovata和梭状芽胞杆菌）以纯Fe0作为电子供体进行了呼吸评估，但只有M.vuluolata,Mx.Soehngenii,和Ovata能够进行不锈钢电生物腐蚀。电生物腐蚀性产甲烷菌需要乙酸盐作为额外的能源，以便从不锈钢中生产甲烷。S.ovata和Mx的共培养。soehngenii证明了在腐蚀过程中，产乙酸菌如何向产甲烷菌提供乙酸盐。甲烷杆菌菌株IM1不仅不能进行电生物腐蚀，但它也不接受金属还原Geobacter的电子，一种有效的供电子伙伴，可将种间电子直接转移到所有可直接接受Fe0电子的产甲烷菌。发现液泡分枝杆菌，Mx.Soehngenii,卵黄链球菌能够进行电生物腐蚀，尽管缺乏以前发现在其他电生物腐蚀性微生物中很重要的外表面c型细胞色素，证明有多种微生物策略与Fe0进行电接触。
