一株鞘氨醇杆菌基于纳米线的胞外电子传递机制研究

微生物胞外电子传递对有机污染物的分解代谢、化学元素循环及能量再生等具有重要意义。目前对于专性好氧微生物的胞外电子传递研究鲜有涉及。前期研究发现专性好氧菌Sphingobium yanoikuyae XLDN2-5能形成具有电活性的生物膜并具有胞外电子传递现象，且该菌在生物膜内生长时会生成导电纳米线，由此提出当该菌在生物膜低溶氧区内生长时可通过胞外电子传递进行胞外呼吸并且在低氧胁迫条件下存在一种新型的基于纳米线胞外电子传递机制的假设。基于以上假设，本项目拟在该菌全基因组测序完成及发现其生成导电纳米线基础上，深入开展该菌在低氧胁迫条件下基于纳米线的胞外电子传递机制研究。通过基因组挖掘、转录组测序分析和Tn5转座诱变等技术筛选该菌利用纳米线进行胞外电子传递的关键基因，并利用基因敲除等方法确定相关基因功能，揭示该菌基于纳米线的胞外电子传递机制，为专性好氧微生物的胞外电子传递研究提供理论基础。

The extracellular electron transfer (EET) of microorganisms is of great significance to organic pollutant biodegradation, chemical element cycle, and energy regeneration. There are few studies on the EET of obligate aerobic microorganisms. We found that Sphingobium yanoikuyae XLDN2-5, a heterocyclic pollutant degrading bacterium, has capabilities to form electroactive biofilm and extracellular transfer electron, and produces conductive nanowires when it grows in the low dissolved oxygen zone of anodic biofilm. Thus, we hypothesized that the obligate aerobic bacterium can carry out extracellular respiration via EET when it grows in the low dissolved oxygen zone of anodic biofilm, and has a novel EET mechanism based on nanowires. Based on the sequencing of the whole genome of S. yanoikuyae XLDN2-5 and the discovery of its conductive nanowires, the nanowires-based EET mechanism of this bacterium will be investigated in this proposal. The key genes of the nanowires-based EET under hypoxia conditions will be characterized by genomic mining, transcriptome analysis, and Tn5 transposon mutagenesis. The functions of key genes will be explored by gene knockout. Based on above research, the nanowires-based EET mechanism will be constructed for S. yanoikuyae XLDN2-5. This proposal will provide a theoretical foundation for the EET mechanism research of obligate aerobic microorganisms.