不同生境来源硝化细菌群对氨氮的去除性能

硝化细菌是微生物脱氮的关键功能菌群之一，筛选优质硝化细菌对于强化微生物脱氮具有重要意义。将河流沉积物、土壤自然环境和市场售人为环境3种生境来源的硝化细菌功能进行比较研究，并利用分子生物学手段分析了硝化细菌群落结构。结果表明，沉积物生境中硝化细菌的活性以及耐氨氮、pH和盐度等环境因子的能力高于土壤和市售硝化细菌。利用MPN-PCR法和克隆文库分析法对各生境硝化细菌丰度及群落结构组成进行分析，发现沉积物生境中硝化螺旋菌(Nitrospira)生物量较高，促使该生境硝化细菌氨氮去除率较高。沉积物生境中硝化细菌的高耐氨氮和耐pH能力与群落中存在硝化杆菌(Nitrobacter)有关，而高耐盐性可能是由于该生境中存在耐盐或适度嗜盐特异基因型硝化细菌，运用Blast程序进行序列比对发现，这些特异基因型硝化细菌为不可培养微生物。

Ammonia nitrogen removal by nitrifying bacteria from different habitats

Nitrifying bacteria are one of the key functional groups in microbial nitrogen removal, and the screening of high-quality nitrifying bacteria is beneficial to enhancing nitrogen removal. The functions of nitrifying bacteria from river sediment, soil natural environment and artificial habitat in the market were compared, and their community structures were analyzed using molecular biological methods. The results showed that the activities of nitrifying bacteria from the sediment habitat and their resistance abilities to ammonia nitrogen, pH and salinity were higher than those from the other two habitats. The abundance and community structure analysis of nitrifying bacteria in each habitat by MPN-PCR and clone library profiling showed that the biomass of Nitrospira in the sediment habitat was high, which could promote the ammonia nitrogen removal rate of nitrifying bacteria in this habitat. For sediment nitrifying bacteria, the higher resistance to ammonium and pH was due to the presence of Nitrobacter, while the higher resistance ability to salinity was possibly due to the presence of salt-tolerant species or moderately halophilic specific genotypes of nitrifying bacteria in the habitat. In addition, these specific genotypes of nitrifying bacteria were identified as uncultured microbes by sequence alignment by Blast program.