The impact that nutrient level has on biofilm characteristics, biocide effectiveness, and the associated risk of microbiologically influenced corrosion (MIC) was assessed using multispecies biofilms from two different oilfield consortia. A range of microbiological, microscopy, and corrosion methods demonstrated that the continuous flow of nutrients for the microbial growth resulted in higher activity, thickness, and robustness of the biofilms formed on carbon steel, which induced greater localized corrosion compared to biofilms formed under batch, nutrient-depleted conditions. Despite of the differences in biofilm characteristics, biofilms displayed comparable susceptibilities to glutaraldehyde biocide, with similar log₁₀ reductions and percent reductions of microorganisms under both nutrient conditions. Nevertheless, nutrient replenishment impacted the effectiveness of the biocide in controlling microbial populations; a higher concentration of cells survived the biocide treatment in biofilms formed under a continuous flow of nutrients. Complementary DNA-/RNA-based amplicon sequencing and bioinformatics analysis were used to discriminate the active within the total populations in biofilms established at the different nutrient conditions and allowed the identification of the microbial species that remained active despite nutrient depletion and biocide treatment. Detection of persistent active microorganisms after exposure to glutaraldehyde, regardless of biofilm structure, suggested the presence of microorganisms less susceptible to this biocide and highlighted the importance of monitoring active microbial species for the early detection of biocide resistance in oil production facilities.

IMPORTANCE Microbiologically influenced corrosion (MIC) is a complex process that generates economic losses to the industry every year. Corrosion must be managed to prevent a loss of containment of produced fluids to the external environment. MIC management includes the identification of assets with higher MIC risk, which could be influenced by nutrient levels in the system. Assessing biofilms under different nutrient conditions is essential for understanding the impact of flow regime on microbial communities and the subsequent impact on microbial corrosion and on the effectiveness of biocide treatment. This investigation simulates closely oil production systems, which contain piping sections exposed to continuous flow and sections that remain stagnant for long periods. Therefore, the results reported here are useful for MIC management and prevention. Moreover, the complementary methodological approach applied in this investigation highlighted the importance of implementing RNA-based methods for better identification of active microorganisms that survive stress conditions in oil systems.

使用来自两个不同油田联合体的多物种生物膜，评估了营养水平对生物膜特性，杀生物剂有效性以及相关的微生物影响的腐蚀（MIC）风险的影响。一系列微生物学，显微镜学和腐蚀方法表明，用于微生物生长的营养素的连续流动导致碳钢上形成的生物膜的活性，厚度和坚固性更高，与分批形成的生物膜相比，这种腐蚀引起更大的局部腐蚀，营养缺乏的条件。尽管生物膜特性存在差异，但生物膜显示出与戊二醛杀生物剂相当的药敏性，log ₁₀相似在两种营养条件下微生物的减少量和减少量百分比。然而，营养补充影响了杀菌剂控制微生物种群的有效性。在连续的营养流下形成的生物膜中，较高浓度的细胞在杀生物剂处理后幸存下来。互补的基于DNA / RNA的扩增子测序和生物信息学分析被用来区分在不同养分条件下建立的生物膜中总种群中的活性，并允许鉴定尽管进行了养分消耗和杀菌剂处理仍保持活性的微生物。不论戊二醛的生物膜结构如何，在暴露于戊二醛后都能检测出持久性活性微生物，

重要性受微生物影响的腐蚀（MIC）是一个复杂的过程，每年都会对该行业造成经济损失。必须控制腐蚀，以防止产出液对外部环境的封闭。MIC管理包括识别具有较高MIC风险的资产，这可能会受到系统中营养水平的影响。评估不同养分条件下的生物膜对于了解流动方式对微生物群落的影响以及随后对微生物腐蚀和杀生物剂处理效果的影响至关重要。这项研究紧密地模拟了采油系统，其中包括暴露于连续流的管道部分和长时间停滞的部分。因此，此处报告的结果对于MIC管理和预防很有用。