Effects of Multiple Electron Acceptors on Microbial Interactions in a Hydrogen-Based Biofilm

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• 作者：He-Ping Zhao ; Zehra Esra Ilhan ; Aura Ontiveros-Valencia ; Youneng Tang ; Bruce E. Rittmann ; Rosa Krajmalnik-Brown
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：July 2, 2013
• 年：2013
• 卷：47
• 期：13
• 页码：7396-7403
• 全文大小：393K
• 年卷期：v.47,no.13(July 2, 2013)
• ISSN：1520-5851

文摘

To investigate interactions among multiple electron acceptors in a H₂-fed biofilm, we operated a membrane biofilm reactor with H₂-delivery capacity sufficient to reduce all acceptors. ClO₄^{鈥?/sup> and O₂ were input electron acceptors in all stages at surface loadings of 0.08 卤 0.006 g/m2-d (1.0 卤 0.7 e鈥?/sup> meq/m2-d) for ClO₄鈥?/sup> and 0.51 g/m2-d (76 e鈥?/sup> meq/m2-d) for O₂. SO₄2鈥?/sup> was added in Stage 2 at 3.77 卤 0.39 g/m2-d (331 卤 34 e鈥?/sup> meq/m2-d), and NO₃鈥?/sup> was further added in Stage 3 at 0.72 卤 0.03 g N/m2-d (312 卤 13 e鈥?/sup> meq/m2-d). At steady state for each stage, ClO₄鈥?/sup>, O₂, and NO₃鈥?/sup> (when present in the influent) were completely reduced; measured SO₄2鈥?/sup> reduction decreased from 78 卤 4% in Stage 2 to 59 卤 4% in Stage 3, when NO₃鈥?/sup> was present. While perchlorate-reducing bacteria (PRB), assayed by qPCR targeting the pcrA gene, remained stable throughout, sulfate-reducing bacteria (SRB), assayed by the dsrA gene, increased almost 3 orders of magnitude when significant SO₄2鈥?/sup> reduction occurred in stage 2. The abundance of denitrifying bacteria (DB), assayed by the nirK and nirS genes, increased in Stage 3, while SRB remained at high numbers, but did not increase. Based on pyrosequencing analyses, 尾-Proteobacteria dominated in Stage 1, but 蔚-Proteobacteria became more important in Stages 2 and 3, when the input of multiple electron acceptors favored genera with broader electron-accepting capabilities. Sulfuricurvum (a sulfur oxidizer and NO₃鈥?/sup> reducer) and Desulfovibrio (a SO₄2鈥?/sup> reducer) become dominant in Stage 3, suggesting redox cycling of sulfur in the biofilm.}