Schwermer Carsten U, Lavik Gaute, Abed Raeid M M, Dunsmore Braden, Ferdelman Timothy G, Stoodley Paul, Gieseke Armin, de Beer Dirk
Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany.
Appl Environ Microbiol. 2008 May;74(9):2841-51. doi: 10.1128/AEM.02027-07. Epub 2008 Mar 14.
We studied the impact of NO(3)(-) on the bacterial community composition, diversity, and function in in situ industrial, anaerobic biofilms by combining microsensor profiling, (15)N and (35)S labeling, and 16S rRNA gene-based fingerprinting. Biofilms were grown on carbon steel coupons within a system designed to treat seawater for injection into an oil field for pressurized oil recovery. NO(3)(-) was added to the seawater in an attempt to prevent bacterial H(2)S generation and microbially influenced corrosion in the field. Microprofiling of nitrogen compounds and redox potential inside the biofilms showed that the zone of highest metabolic activity was located close to the metal surface, correlating with a high bacterial abundance in this zone. Upon addition, NO(3)(-) was mainly reduced to NO(2)(-). In biofilms grown in the absence of NO(3)(-), redox potentials of <-450 mV at the metal surface suggested the release of Fe(2+). NO(3)(-) addition to previously untreated biofilms induced a decline (65%) in bacterial species richness, with Methylophaga- and Colwellia-related sequences having the highest number of obtained clones in the clone library. In contrast, no changes in community composition and potential NO(3)(-) reduction occurred upon subsequent withdrawal of NO(3)(-). Active sulfate reduction was below detection levels in all biofilms, but S isotope fractionation analysis of sulfide deposits suggested that it must have occurred either at low rates or episodically. Scanning electron microscopy revealed that pitting corrosion occurred on all coupons, independent of the treatment. However, uniform corrosion was clearly mitigated by NO(3)(-) addition.
我们通过结合微传感器分析、（15）N和（35）S标记以及基于16S rRNA基因的指纹识别技术，研究了硝酸根离子（NO₃⁻）对原位工业厌氧生物膜中细菌群落组成、多样性和功能的影响。生物膜生长在碳钢试片上，该系统旨在处理用于注入油田以进行加压采油的海水。向海水中添加NO₃⁻，试图防止现场细菌产生硫化氢（H₂S）以及微生物影响的腐蚀。生物膜内氮化合物和氧化还原电位的微分析表明，最高代谢活性区域位于靠近金属表面的位置，这与该区域的高细菌丰度相关。添加后，NO₃⁻主要被还原为亚硝酸根离子（NO₂⁻）。在没有NO₃⁻的情况下生长的生物膜中，金属表面氧化还原电位<-450 mV表明有亚铁离子（Fe²⁺）释放。向先前未处理的生物膜中添加NO₃⁻会导致细菌物种丰富度下降（65%），在克隆文库中，与嗜甲基菌属和考氏菌属相关的序列获得的克隆数量最多。相比之下，随后去除NO₃⁻后，群落组成和潜在的NO₃⁻还原没有变化。所有生物膜中的活性硫酸盐还原均低于检测水平，但硫化物沉积物的硫同位素分馏分析表明，它必定是以低速率或间歇性地发生。扫描电子显微镜显示，所有试片上均出现点蚀，与处理方式无关。然而，添加NO₃⁻明显减轻了均匀腐蚀。
