Shenyang National Laboratory for Materials Science, Northeastern University, Shenyang, 110819, China; Electrobiomaterials Institute, Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang, 110819, China; Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang, 110819, China.
Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, Tianjin, 300072, China.
Water Res. 2022 Jul 1;219:118553. doi: 10.1016/j.watres.2022.118553. Epub 2022 May 5.
Shewanella oneidensis MR-1 is an attractive model microbe for elucidating the biofilm-metal interactions that contribute to the billions of dollars in corrosion damage to industrial applications each year. Multiple mechanisms for S. oneidensis-enhanced corrosion have been proposed, but none of these mechanisms have previously been rigorously investigated with methods that rule out alternative routes for electron transfer. We found that S. oneidensis grown under aerobic conditions formed thick biofilms (∼50 µm) on stainless steel coupons, accelerating corrosion over sterile controls. H and flavins were ruled out as intermediary electron carriers because stainless steel did not reduce riboflavin and previous studies have demonstrated stainless does not generate H. Strain ∆mtrCBA, in which the genes for the most abundant porin-cytochrome conduit in S. oneidensis were deleted, corroded stainless steel substantially less than wild-type in aerobic cultures. Wild-type biofilms readily reduced nitrate with stainless steel as the sole electron donor under anaerobic conditions, but strain ∆mtrCBA did not. These results demonstrate that S. oneidensis can directly consume electrons from iron-containing metals and illustrate how direct metal-to-microbe electron transfer can be an important route for corrosion, even in aerobic environments.
希瓦氏菌属（Shewanella oneidensis）MR-1 是一种有吸引力的模式微生物，可用于阐明导致每年数十亿美元工业应用腐蚀损坏的生物膜-金属相互作用。已经提出了多种希瓦氏菌属增强腐蚀的机制，但这些机制以前都没有用排除电子转移替代途径的方法进行严格研究。我们发现，在需氧条件下生长的希瓦氏菌属在不锈钢片上形成了厚厚的生物膜（约 50µm），加速了无菌对照的腐蚀。H 和黄素被排除为中间电子载体，因为不锈钢不会还原核黄素，而且先前的研究已经证明不锈钢不会产生 H。在需氧培养物中，缺失了希瓦氏菌属中最丰富的孔蛋白-细胞色素管道的基因的菌株 ∆mtrCBA 比野生型对不锈钢的腐蚀要小得多。在厌氧条件下，野生型生物膜很容易用不锈钢作为唯一的电子供体还原硝酸盐，但菌株 ∆mtrCBA 则不能。这些结果表明，希瓦氏菌属可以直接从含铁金属中消耗电子，并说明了直接的金属-微生物电子转移如何成为腐蚀的重要途径，即使在有氧环境中也是如此。
