单室微生物电解池除镍途径分析及微生物群落动态特征

Removal of Ni (II) and microbial dynamics in single-chamber microbial electrolysis cell

摘要:

[目的] 为探究UASB颗粒污泥启动的单室微生物电解池（Single-chamber microbial electrolysis cell，SMEC）对Ni（Ⅱ）的去除途径和SMEC中微生物群落的动态特征。[方法] 以乙酸钠为底物，采用单因子控制方法分析SMEC对Ni（Ⅱ）的去除途径和应用Illumina高通量测序技术解析SMEC启动过程中微生物群落的组成和结构动态学特征。[结果] 结果表明，SMEC对重金属的去除主要通过吸附和微生物作用。经培养驯化功能菌群发生变化。成熟单室微生物燃料电池（Single-chamber microbial fuel cell，SMFC）阳极生物膜菌群主要是Proteobacteria（变形菌门，91.42%）中的Geobacter sp.（地杆菌属，76.25%）；阴极生物膜菌群主要是Bacteroidetes（拟杆菌门，47.99%）中的Niabella sp.（布鲁氏菌属，33.01%）和Proteobacteria（45.74%）中的Ochrobactrum sp.（苍白杆菌属，10.80%）。成熟SMFC改装成的SMEC在12.5 mg-Ni（Ⅱ）/L下，阳极生物膜菌群由单一优势菌Geobacter sp.转变为Geobacter sp.（41.56%）和Proteobacteria中的Azospirillum sp.（固氮螺菌属，5.97%）；阴极生物膜菌群由Niabella sp.和Ochrobactrum sp.转变为Firmicutes（厚壁菌门，25.21%）中的Acetoanaerobium sp.（19.28%）、Proteobacteria（51.42%）中的Dokdonella sp.（16.48%）和Azospirillum sp.（9.49%）。[结论] 本研究表明，污泥微生物经SMFC和SMEC驯化过程及Ni（Ⅱ）的淘汰和选择，在电极上形成了稳定、高效产电与除镍菌群，优势菌群为Proteobacteria。

Abstract:

[Objective] Single-chamber microbial electrolysis cell (SMEC), inoculated by granular sludge from upflow anaerobic sludge bed, can remove Ni(Ⅱ). Therefore, it is of great significance to explore the role microbial community to remove Ni(Ⅱ) in SMEC.[Methods] With sodium acetate as substrate, single-factor control method and Illumina high-throughput sequencing were applied to analyze Ni(Ⅱ) removal, as well as microbial community structure and dynamic characteristics in SMEC.[Results] Adsorption and microbial functions were the major mechanisms for removing Ni(Ⅱ). In mature single-chamber microbial fuel cell (SMFC), Geobacter sp. of Proteobacteria (91.42%) was dominant on the anode with an abundance of 76.25% whereas Niabella sp. of Bacteroidetes (47.99%) was dominant on the cathode with an abundance of 33.01%, followed by Ochrobactrum sp. of Poribacteria (45.74%) accounting for 10.08%. In SMEC modified from mature SMFC with 12.5 mg-Ni(Ⅱ)/L, the dominant bacteria turned from single Geobacter sp. to Geobacter sp. (41.56%) and Azospirillum sp. (5.97%) on the anode; the dominant bacteria on the cathode turned from Niabella sp. and Ochrobactrum sp. to Acetoanaerobium sp. (19.28%), Dokdonella sp. (16.48%) and Azospirillum sp. (9.49%).[Conclusion] Microbial populations in raw sludge were selectively acclimated in the Ni(Ⅱ) removal process of SMEC, and effective microbial communities of electrogenesis and nickel removal were built on the electrode to promote the removal of Ni(Ⅱ) in SMEC.