Wang Di, Ueki Toshiyuki, Ma Peiyu, Xu Dake, Lovley Derek R
Electrobiomaterials Institute, Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education) Northeastern University Shenyang China.
Shenyang National Laboratory for Materials Science Northeastern University Shenyang China.
mLife. 2024 Jun 28;3(2):269-276. doi: 10.1002/mlf2.12133. eCollection 2024 Jun.
Sulfate-reducing microorganisms extensively contribute to the corrosion of ferrous metal infrastructure. There is substantial debate over their corrosion mechanisms. We investigated Fe corrosion with , the sulfate reducer most often employed in corrosion studies. Cultures were grown with both lactate and Fe as potential electron donors to replicate the common environmental condition in which organic substrates help fuel the growth of corrosive microbes. Fe was corroded in cultures of a hydrogenase-deficient mutant with the 1:1 correspondence between Fe loss and H accumulation expected for Fe oxidation coupled to H reduction to H. This result and the extent of sulfate reduction indicated that was not capable of direct Fe-to-microbe electron transfer even though it was provided with a supplementary energy source in the presence of abundant ferrous sulfide. Corrosion in the hydrogenase-deficient mutant cultures was greater than in sterile controls, demonstrating that H removal was not necessary for the enhanced corrosion observed in the presence of microbes. The parental H-consuming strain corroded more Fe than the mutant strain, which could be attributed to H oxidation coupled to sulfate reduction, producing sulfide that further stimulated Fe oxidation. The results suggest that H consumption is not necessary for microbially enhanced corrosion, but H oxidation can indirectly promote corrosion by increasing sulfide generation from sulfate reduction. The finding that was incapable of direct electron uptake from Fe reaffirms that direct metal-to-microbe electron transfer has yet to be rigorously described in sulfate-reducing microbes.
硫酸盐还原微生物对黑色金属基础设施的腐蚀有广泛影响。关于它们的腐蚀机制存在大量争论。我们用腐蚀研究中最常使用的硫酸盐还原菌来研究铁的腐蚀。培养物以乳酸盐和铁作为潜在电子供体生长，以复制有机底物促进腐蚀性微生物生长的常见环境条件。在一个缺乏氢化酶的突变体培养物中，铁被腐蚀，铁的损失与氢的积累之间存在1:1的对应关系，这是铁氧化与氢还原为氢所预期的。这一结果和硫酸盐还原的程度表明，即使在存在大量硫化亚铁的情况下提供了补充能源，该硫酸盐还原菌也不能进行直接的铁到微生物的电子转移。缺乏氢化酶的突变体培养物中的腐蚀比无菌对照中的更大，这表明在有微生物存在时观察到的腐蚀增强并不需要去除氢。亲本耗氢菌株比突变菌株腐蚀更多的铁，这可能归因于与硫酸盐还原偶联的氢氧化，产生的硫化物进一步刺激铁的氧化。结果表明，微生物增强腐蚀并不需要消耗氢，但氢氧化可以通过增加硫酸盐还原产生的硫化物来间接促进腐蚀。该硫酸盐还原菌不能直接从铁摄取电子这一发现再次证实，在硫酸盐还原微生物中，直接的金属到微生物的电子转移尚未得到严格描述。
