RESUMO
Nitrite-dependent anaerobic methane oxidation (N-DAMO) is a recently discovered process linking the global carbon and nitrogen cycles. This process was reported to be mediated by "Candidatus Methylomirabilis oxyfera". To date, M. oxyfera-like bacteria have been detected in a limited number of freshwater habitats, but whether these bacteria occur in estuarine habitats is currently unknown. In this study, the distribution, diversity and abundance of M. oxyfera-like bacteria were studied in the sediment of the Jiaojiang Estuary of the East Sea (China). Both the 16S ribosomal RNA (rRNA) and pmoA genes confirmed the occurrence of M. oxyfera-like bacteria in the examined estuary. The recovered 16S rRNA gene sequences showed 91.5-97.2 % identity to the 16S rRNA gene of M. oxyfera, and the recovered pmoA gene sequences showed 85.1-95.4 % identity to the pmoA gene of M. oxyfera. Quantitative PCR further confirmed the occurrence of M. oxyfera-like bacteria in this estuary, with the abundance varying from 5.80 ± 0.28 × 10(4) to 8.35 ± 0.52 × 10(7) copies g (dry weight)(-1). Correlation analysis indicated that the sediment organic content was the most important factor affecting the distribution of M. oxyfera-like bacterial communities in the examined sediments among the environmental factors investigated. This study demonstrated for the first time the existence of M. oxyfera-like bacteria in an estuarine environment and showed the correlations between the distribution of these bacteria and the estuarine environmental conditions.
Assuntos
Bactérias/isolamento & purificação , Bactérias/metabolismo , Sedimentos Geológicos/microbiologia , Metano/metabolismo , Nitritos/metabolismo , Anaerobiose , Bactérias/classificação , Bactérias/genética , Proteínas de Bactérias/genética , China , Análise por Conglomerados , DNA Ribossômico/química , DNA Ribossômico/genética , Estuários , Dados de Sequência Molecular , Oxirredução , Filogenia , RNA Ribossômico 16S/genética , Água do Mar , Análise de Sequência de DNARESUMO
Three activated sludges from a landfill leachate treatment plant (S1), a municipal sewage treatment plant (S2) and a monosodium glutamate (MSG) wastewater treatment plant (S3) were used as inocula to enrich anaerobic ammonium oxidation (anammox) bacteria for the startup of MSG industrial wastewater treatment system. After 360 days of cultivation using MSG wastewater, obvious anammox activity was observed in all three cultures. The maximum specific anammox activities of cultures S1, S2 and S3 were 0.11 kg N kg(-1) VSS day(-1), 0.09 kg N kg(-1) VSS day(-1) and 0.16 kg N kg(-1) VSS day(-1), respectively. Brownish-red anammox granules having diameters in the range of 0.2-1.0mm were visible in cultures S1 and S2, and large red granules having diameters in the range of 0.5-2.5mm were formed in culture S3 after 420 days of cultivation. Phylogenetic analysis of 16S rRNA genes showed that Kuenenia organisms were the dominant anammox species in all three cultures. The copy numbers of 16S rRNA genes of anammox bacteria in cultures S1, S2 and S3 were 6.8 × 10(7) copies mL(-1), 9.4 × 10(7) copies mL(-1) and 7.5 × 10(8) copies mL(-1), respectively. The results of this study demonstrated that anammox cultivation from conventional activated sludges was highly possible using MSG wastewater. Thus the anammox process has possibility of applying to the nitrogen removal from MSG wastewater.