自养条件下高氯酸盐降解细菌群落研究

The Study of the Structure of Perchlorate(ClO_4^-)-degrading Bacterial Communities Under Autotrophic Conditions

旨在研究自养条件下以氢气作为电子供体高氯酸根离子(ClO4-)的微生物降解机制,利用HiSeq 2000对微生物群落结构及多样性进行高通量测序及分析。结果表明,添加氢气的HD(hydrogen degradation)体系将10 mg/L ClO4-降至检出限以下共经历71 d。ClO4-完全降解后HD体系中总细菌的相对丰度为84.96%,绝大多数降解细菌分布的变形菌门相对丰度为68.11%,占总细菌数的比例达到80.16%。其中属于β-变形杆菌纲的ClO4-代表性降解细菌(perchlorate-reducing bacteria,PRB)Dechloromonas的相对丰度为2.7%,另一种Azospira为3.1%。通过KEGG注释对菌种功能进行分析。参与糖代谢的基因相对丰度为4.75%,参与能量代谢的基因相对丰度为3.35%,其中参与氮循环的基因相对丰度为0.72%,参与氯代物降解和氯循环的基因相对丰度为0.83%,补充氢气对反应体系内生物群落结构变化起到选择纯化作用,使优势菌群趋于单一。

For the purpose of further investigating the biological degradation under an autotrophic condition and well understanding the microbial community structures in a complex environment, hydrogen was used as an electron donor to completely reduce perchlorate（ClO4-）in this study. The composition of microbial communities after degradation was analyzed via the construction of a cloning library by using the High-Throughput Sequencing method（HiSeq 2000）. 71 days were needed to completely degrade 10 mg/L ClO4-. Microbial phylogenic analysis of HD（hydrogen degradation）after degradation indicated that the relative abundance of total bacteria in the HD was 84.96%whereas the relative abundance of Proteobacteria was 68.11%, whose percentage accounting for the total bacteria reached to 80.16%. The relative abundance of Dechloromonas which is representative in PRB was 2.7%in the HD. Simultaneously, the relative abundance of Azospira was 3.1%. KEGG was used to analyze the function of bacteria in HD. The relative abundance of genes which engaged in carbohydrate metabolism was 4.75%, and the genes included in energy metabolism was 3.35%, whereas the genes participated in nitrogen cycle was 0.72%, and the genes involving chloride transformation was 0.83%. It was demonstrated that degradation of ClO4-in a complicated condition was achieved by various kinds of microbes rather than a single one. Adding hydrogen as an electron donor to change microbial community played a role in the purification or selection process in the system, which allowed the complex systems to have the specific capacity to remove given contaminates.