RESUMO
Wastewater microbiota represents important actors of organic depollution. Nowadays, some species used as bioindicators of the effluent quality are still identified by microscopy. In the present study, we investigated eukaryotic diversity at the different steps of the treatment process of a wastewater treatment plant (aerobic, anaerobic, clarifier basins and anaerobic digester) using the 18S rRNA gene sequencing approach. Of the 1519 analysed sequences, we identified 160 operational taxonomic units. Interestingly, 56.9% of the phylotypes were assigned to novel phylogenetic molecular species since they show <97% sequence identity with their nearest affiliated representative within public databases. Peritrichia ciliates were the most predominant group, with Epistylis as the most common genus. Although anaerobic, the digester appears to harbor many unclassified phylotypes of protozoa species. Novel lineages such as LKM11 and LKM118 were widely represented in the digester. Diversity values given by Shannon indexes show that the clarifier is the most diversified. This work will help designing molecular tools that are fast, reliable, and reproducible for monitoring wastewater depollution and studying phylogenetic relationships among the wonderful world of protists within this anthropogenic ecosystem.
Assuntos
Eucariotos/classificação , Eucariotos/genética , Águas Residuárias/microbiologia , Alveolados/classificação , Alveolados/genética , Sequência de Bases , Biodiversidade , Cilióforos/classificação , Cilióforos/genética , Monitoramento Ambiental , Fungos/classificação , Fungos/genética , Variação Genética , Microbiota/genética , Filogenia , RNA Ribossômico 18S/genética , Análise de Sequência de DNA , Esgotos/microbiologia , Purificação da ÁguaRESUMO
In this study, bacterial community structure in a horizontal subsurface flow constructed wetland (HSF-CW) planted with Phragmites australis was investigated using the 16S rRNA cloning-sequencing technique. Two layer depths were considered: the rhizosphere zone (RH) and the deep-layer zone (DL) in different sampling periods. Bacteria-specific primers 008F and 1492R were used to amplify the 16S rRNA genes and construct six clone libraries. A total of 1,284 individual sequences were used to assess the HSF-CW diversity. Phylogenetic analysis of RH and DL clone libraries shows that 41.57 and 42.17 % of the 16S rRNA sequences are affiliated with the Proteobacteria in the RH and the DL, respectively. The remaining major phylogenetic groups are Bacteroidetes, Planctomycetes, and Chloroflexi with 11.78, 9.36, and 7.6 %, respectively, in the RH and 11.38, 6.48, and 7.65 % in the DL, respectively. Minor divisions such as Verrucomicrobia, TM7, Nitrospira, and Gemmatimonadetes represented <6 % of the total sequences, while 14.2 % were unidentified Bacteria. Among the Proteobacteria, the Alphaproteobacteria subclass is represented in both locations, while the Deltaproteobacteria and Gammaproteobacteria subclasses were predominant in the RH and the DL, respectively. Results suggest that Archaea and Bacteria in the HSF-CW are the essential actors in the nitrogen cycle and that the established microbial community is efficient in nitrogen removal from wastewater.
Assuntos
Bactérias/classificação , Biota , Microbiologia Ambiental , Filogeografia , Áreas Alagadas , Archaea/classificação , Archaea/genética , Bactérias/genética , Análise por Conglomerados , DNA Arqueal/química , DNA Arqueal/genética , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Genes de RNAr , Dados de Sequência Molecular , RNA Arqueal/genética , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico , Fatores de TempoRESUMO
Performance of biological wastewater treatment systems may be related to the composition and activity of microbial populations they contain. However, little information is known regarding microbial community inhabiting these ecosystems. The purpose of this study was to investigate archaeal and bacterial diversity, using cultivation-independent molecular techniques, in a constructed wetland receiving domestic wastewater. Two 16S rRNA gene libraries were constructed using total genomic DNA and amplified by PCR using primers specific for archaeal and bacterial domains. A high microbial diversity was detected. The Proteobacteria phylum is the most abundant and diversified phylogenetic group representing 31.3 % of the OTUs, followed by the Bacteroidetes (14.8 %), Planctomycetales (13.8 %), Actinobacteria (12 %), and Chloroflexi (8.2 %). Sequences affiliated with minor phylogenetic divisions such as the TM7, Nitrospira, OP10, and BRC1 are represented by <6 % of total OTUs. The Archaea domain was represented by the Thaumarchaeota phylum dominated by the Candidatus Nitrososphaera genus.
Assuntos
Archaea/metabolismo , Reação em Cadeia da Polimerase/métodos , Áreas Alagadas , Rizosfera , Eliminação de Resíduos Líquidos/métodosRESUMO
In this study, archaeal community structure and temporal dynamics were monitored, using 16S rRNA clone libraries construction from a horizontal subsurface flow constructed wetland. Phylogenetic assignation of 1026 16S rRNA gene sequences shows that 96.2% of the total operational taxonomic units (OTUs) were affiliated with Thaumarchaeota, a newly proposed archaeal phylum and 3.7% with unclassified Archaea. Among the total sequences, 42% and 40.2% were affiliated with Candidatus Nitrososphaera and unclassified Nitrosopumilus respectively with more than 99% similarity. Results suggest that several dominant and active nitrifiers may benefit from the micro-aerobic conditions around the reed roots to perform ammonia oxidation. The archaeal diversity detected in the rhizosphere zone is clearly different from that detected in the bottom basin. This engineered habitat revealed the reed root and the water composition effects on the archaeal diversity.