France Danielle Cook
National Institute of Standards and Technology, Boulder, CO, USA.
J Mater Eng Perform. 2016 Sep;25(9):3580-3589. doi: 10.1007/s11665-016-2231-0. Epub 2016 Jul 19.
Microbiologically influenced corrosion (MIC) of carbon steel infrastructure is an emerging environmental and cost issue for the ethanol fuel industry, yet its examination lacks rigorous quantification of microbiological parameters that could reveal effective intervention strategies. To quantitatively characterize the effect of cell concentration on MIC of carbon steel, numbers of bacteria exposed to test coupons were systematically controlled to span four orders of magnitude throughout a seven-day test. The bacterium studied, , has been found in ethanol fuel environments, and can convert ethanol to the corrosive species acetic acid. biofilms formed during the test were qualitatively evaluated with fluorescence microscopy, and steel surfaces were characterized by scanning electron microscopy. During exposure, biofilms developed more quickly, and test reactor pH decreased at a faster rate, when cell exposure was higher. Resulting corrosion rates, however, were inversely proportional to cell exposure, indicating that biofilms are able to protect carbon steel surfaces from corrosion. This is a novel demonstration of corrosion inhibition by an acid-producing bacterium that occurs naturally in corrosive environments. Mitigation techniques for MIC that harness the power of microbial communities have the potential to be scalable, inexpensive, and green solutions to industrial problems.
碳钢基础设施的微生物影响腐蚀（MIC）是乙醇燃料行业新出现的一个环境和成本问题，然而对其研究缺乏对微生物参数的严格量化，而这些参数可能揭示有效的干预策略。为了定量表征细胞浓度对碳钢MIC的影响，在为期七天的测试中，系统地控制了暴露于测试 coupons 的细菌数量，使其跨越四个数量级。所研究的细菌 ，已在乙醇燃料环境中被发现，并且可以将乙醇转化为腐蚀性物质乙酸。用荧光显微镜对测试过程中形成的生物膜进行了定性评估，并用扫描电子显微镜对钢表面进行了表征。在暴露过程中，当细胞暴露量较高时，生物膜形成得更快，测试反应器的pH值下降得更快。然而，由此产生的腐蚀速率与细胞暴露量成反比，这表明 生物膜能够保护碳钢表面免受腐蚀。这是对在腐蚀性环境中自然存在的产酸细菌抑制腐蚀的一种新颖证明。利用微生物群落力量的MIC缓解技术有可能成为解决工业问题的可扩展、低成本和绿色解决方案。
