Microbial Corrosion Laboratory, Estácio University (UNESA), Bispo Street, 83, Room, AG405, Rio de Janeiro, Rio de Janeiro, ZIP Code 20261-063, Brazil.
Industrial Microbiology and Bioremediation Department, Federal University of Rio de Janeiro (UFRJ), Caxias, Rio de Janeiro, Brazil.
Biotechnol Lett. 2020 Aug;42(8):1431-1448. doi: 10.1007/s10529-020-02927-9. Epub 2020 May 29.
In order to evaluate the corrosive action of microorganisms on 316L metal exposed directly to a marine environment, a system was designed to immerse coupons in seawater. After periods of 30, 60 and 90 days, the coupons were recovered, the corrosion rates evaluated and the biofilm samples on their surface were analyzed by 16S rRNA gene sequencing. The results of the corrosion rate showed an acceleration over the entire experimental period. Alpha diversity measurements showed higher rates after 60 days of the experiment, while abundance measurements showed higher rates after 90 days of exposure to the marine environment. The beta-diversity results showed a clear separation between the three conditions and proximity in the indices between replicates of the same experimental condition. The results of 16S rRNA gene sequencing showed that after 30 days of exposure to seawater, there was massive representativeness of the pioneer bacteria, Gamma and Alphaproteobacteria, with emphasis on the genera Alcanivorax, Oceanospirillum and Shewanella. At the 60-day analysis, the Gammaproteobacteria class remained dominant, followed by Alphaproteobacteria and Flavobacteria, and the main representatives were Flexibacter and Pseudoalteromonas. In the last analysis, after 90 days, a change in the described bacterial community profile was observed. The Gammaproteobacteria class was still the largest in diversity and OTUs. The most predominant genera in number of OTUs were Alteromonas, Bacteriovorax and, Nautella. Our results describe a change in the microbial community over coupons directly exposed to the marine environment, suggesting a redirection to the formation of a mature biofilm. The conditions created by the biofilm structure suggest said condition favor biocorrosion on the analyzed coupons.
为了评估直接暴露于海洋环境中的 316L 金属微生物的腐蚀性作用，设计了一种将金属试片浸入海水中的系统。经过 30、60 和 90 天的时间后，取回金属试片，评估腐蚀速率，并通过 16S rRNA 基因测序分析其表面的生物膜样本。腐蚀速率的结果表明，在整个实验期间腐蚀速率加速。多样性测量结果表明，在实验进行 60 天后，速率更高，而丰度测量结果表明，在暴露于海洋环境 90 天后，速率更高。β多样性结果表明，三种条件之间存在明显的分离，并且同一实验条件的重复之间的指数接近。16S rRNA 基因测序结果表明，在暴露于海水 30 天后，大量的先驱细菌，γ和α变形菌，以 Alcanivorax、Oceanospirillum 和 Shewanella 属为代表。在 60 天的分析中，γ变形菌门仍然占主导地位，其次是α变形菌门和黄杆菌门，主要代表是 Flexibacter 和 Pseudoalteromonas。在最后一次分析中，在 90 天后，观察到描述的细菌群落组成发生了变化。γ变形菌门在多样性和 OTUs 方面仍然是最大的。OTUs 数量最多的主要属是 Alteromonas、Bacteriovorax 和 Nautella。我们的研究结果描述了直接暴露于海洋环境中的金属试片上微生物群落的变化，表明微生物群落向成熟生物膜的形成方向发生了转变。生物膜结构所创造的条件表明，这种条件有利于分析试片上的生物腐蚀。
