循环海水养殖系统硝化滤器中氨氧化微生物分析

摘要

研究循环水养殖硝化滤器裁体上附着生物膜的微生物群落结构可以为提高其处理速率和数率,并为特异性工程菌构建提供依据.采用改良的AFLP方法分析了循环水养殖硝化滤器载体上附着的氨氧化细菌16S rRNA基因和氨单加氧酶amoA基因片段及其系统发育情况.结果表明:分析16S rRNA基因得到的序列片段比分析amoA基因片段得到了更多信息,准确度较高,可作为分析循环水养殖硝化滤器氨氧化茵群组成的有效方法.克隆测序所得序列与网上公布数据比对,可见存在于循环水养殖硝化滤器载体上的氨氧化细菌与Nitrosomonas cryotolerans、Nitrosomonas oligotropha、Nitrosospira tenuis、Nitrosomonasmarina相似度达100％,与Nitrosomornas aestuarii相似度为87％.大部分属于亚硝化单胞茵属(Nitrosomonns),仅少数序列属于亚硝化螺茵属(Nitrosospira).采用16S rRNA基因和amoA片段分析方法得到的附着于封闭循环海水养殖硝化滤器载体上的氨氧化细菌主要为变形茵(Proteobacteria)的β-亚类的亚硝化单胞茵属(Nitrosomonas)和少量的亚硝化螺茵属(Nitrosospira)氨氧化细菌,以及一定数量的y-亚类氨氧化细菌.%Ammonia-oxidizing bacteria (AOB) play an important role in transformation from ammonia nitrogen to nitrite nitrogen in the nitrifying biofilter.Studying community structure of nitrifying organisms adhered on the media of nitrification biofilter in the recirculating aquaculture system (RAS) could provide a basis of improving removal rate and performance of biofilter,and construction of nitrifying engineering bacteria for removal of ammonia from RAS.The PCR-based gene cloning and mapping of 16S rRNA gene and betaproteobacteria ammonia monooxygenase subunit A (amoA) gene of ammonia-oxidizing bacteria isolated from nitrification biofilter were surveyed by using the method of improved amplified fragment length polymorphism (AFLP) analysis.The results showed that the information of AOB using 16S rRNA gene cloning is more than using amoA gene cloning.We used GenBank BLAST to search for best matches for the obtained sequences,the AOB in the nitrification biofilter were much closed to Nitrosomonas cryotolerans,Nitrosomonas oligotropha,Nitrosospira tenuis,Nitrosomonas marina with 100% of similarity and Nitro-somonas aestuarii with 87% of similarity.The AOB in the nitrification biofilter of RAS belong to the β-subclass of Proteobacteria,Nitrosomonas and Nitrosospira.Nitrosospira-like sequences were detected.