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The slow startup is the major obstacle to the application of anaerobic ammonium oxidation (anammox) process in mainstream wastewater treatment. Extracellular polymeric substances (EPS) are one potential resource for stable anammox reactor operation. Response surface analysis was used to optimize the specific anammox activity (SAA) with the addition of EPS; SAA was maximum at a temperature of 35 °C and the EPS concentration of 4 mg/L. By comparing the nitrogen removal of anammox reactors with no EPS (R0), immobilized EPS (EPS-alginate beads) (R1), and liquid EPS (R2), we found that EPS-alginate beads significantly speed up the startup of anammox process and enable the start time to be shortened from 31 to 19 days. As a result of the higher MLVSS content, higher zeta potential, and lower SVI30, anammox granules of R1 exhibited a stronger capacity to aggregate. Moreover, EPS extracted from R1 had higher flocculation efficiencies than EPS derived from R0 and R2. Phylogenetic analysis of 16S rRNA genes revealed that the main anammox species in R1 is Kuenenia taxon. To clarify the relative significance of stochastic vs deterministic processes in the anammox community, neutral model and network analysis are employed. In R1, community assembly became more deterministic and stable than in other cultures. Our results show that EPS might inhibit heterotrophic denitrification and thereby promote anammox activity. This study suggested a quick start-up strategy for the anammox process based on resource recovery, which is helpful for environmentally sustainable and energy-efficient wastewater treatment.
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Reatores Biológicos , Matriz Extracelular de Substâncias Poliméricas , Reatores Biológicos/microbiologia , Filogenia , Oxidação Anaeróbia da Amônia , RNA Ribossômico 16S , Esgotos , Oxirredução , Nitrogênio/farmacologia , Desnitrificação , AnaerobioseRESUMO
Researching the structure and function of sediment microbiome contribute to understanding the response of microbiome to external disturbances. However, seasonal changes in sediment microbiome with different terrestrial pollutants input have not yet been clearly understood. Metagenomic sequencing was used to evaluate the effects of seasonal variations and different land use types on sediment microbiome. Results showed that the differences in structure and functions of sediment microbiome among different land use types were obviously greater than different seasons. This indicated that the terrestrial pollutants weakened the effects of seasonal variations on shaping the sediment microbiome. The significant differences in sediment properties under the input of different terrestrial pollutants was observed, but no obvious differences between seasons, which may be the reason why terrestrial pollutants override the effects of seasonal variation on the sediment microbiome. Overall, the results extended our understanding of the impacts of seasonal variation and terrestrial pollutants on river sediment microbiome.
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Monitoramento Ambiental/métodos , Sedimentos Geológicos/microbiologia , Microbiota/genética , Poluentes Químicos da Água/análise , Poluentes Ambientais , Sedimentos Geológicos/química , Rios/química , Estações do AnoRESUMO
An in situ integrated system, consisting of ecological floating islands (EFI), ecological riverbeds (ER), and ecological filter dams (EFD), was built in a ditch only receiving the effluent of sewage plant; the effect of in situ technologies on the distribution of aquatic pathogen was investigated. The results showed the aquatic pathogen decreased along the ditch. Specifically, the relative abundance of Legionella, Aeromonas, and Acinetobacter decreased from 0.032, 0.035, and 0.26 to 0.026%, 0.012%, and 0.08%, respectively. Sedimentation, filtration, and sorption (provided by plant roots and biofilms on substrates) were principal processes for the removal. The nitrogen removal bacteria to prevent the potential risk of eutrophication were also evaluated. The EFI and ER were the dominant sites for Nitrosomonas (34.96%, 32.84%) and Nitrospira (35.74%, 54.73%) enrichment, while EFI and EFD facilitated the enrichment of denitrification bacteria. Notably, the relative abundance of endogenous denitrifiers (DNB-en) (including Dechloromonas at 9.72%, Thermomonas at 0.58%, and Saccharibacteria at 2.55%) exceeded those of exogenous denitrifiers (DNB-ex) (Thauera at 0.20%, Staphylococcus at 0.005%, and Rhodobacter at 0.27%). This study demonstrated that the in situ integrated system was effective in reducing the abundance of pathogens in the drainage channel, and the deficiency of DNB-ex and carbon sources made nitrate removal difficult.
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Rios , Esgotos , Esgotos/microbiologia , Rios/microbiologia , Eliminação de Resíduos Líquidos/métodosRESUMO
Rhizosphere microflora are key determinants that contribute to plant growth and productivity, which are involved in improving the uptake of nutrients, regulation of plants' metabolisms and activation of plants' responses against both biotic and abiotic stresses. However, the structure and diversity of the grape rhizosphere microbiota remains poorly described. To gain a detailed understanding of the assembly of rhizosphere microbiota, we investigated the rhizosphere microbiota of nine grape varieties in northern China by high-throughput sequencing. We found that the richness and diversity of bacterial and fungal community networking in the root compartments were significantly influenced by the grape variety. The bacterial linear discriminant analysis showed that Pseudomonas and Rhizobium, which were considered as potential plant-growth-promoting bacteria, were more enriched in Pinot noir, and Nitrosospira was enriched in Gem. The fungal linear discriminant analysis showed that Fusarium was more enriched in Longan, Sporormiella was more enriched in Merlot, Gibberella and Pseudallescheria were more enriched in Gem and Mortierella was more abundant in Cabernet Sauvignon. The 16S rRNA functional prediction indicated that no significance differentiates among the grape varieties. Understanding the rhizosphere soil microbial diversity characteristics of different grape varieties could provide the basis for exploring microbial associations and maintaining the health of grapes.
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This present article explores the effects of cultural value, economic prosperity, and community mental wellbeing through multi-sectoral infrastructure growth projects under the Belt and Road Initiative. The implications of the social exchange theory are applied to observe the support of the local community for the China-Pakistan Economic Corridor (CPEC). This study explores the CPEC initiative, it's direct social, cultural, economic development, and risk of environmental factors that affect residents' lives and the local community's wellbeing. CPEC is a multibillion-dollar project to uplift economic growth and free trade between Pakistan, China, and other regional stakeholders. Although CPEC is still in its initial phases with partial startups, policymakers and government officials claim this mega project as a "game-changer" in the region, mainly for Pakistan and China. This gigantic project offers the significant potential to generate business slews and employment opportunities with international outreach. Due to the term's newness, numerous studies have recently explored the macro and microeconomic benefits of the CPEC initiatives; still, these projects are theoretical. The existing literature insufficiently explored how helpful CPEC would be to a specific group and how residents perceive its advantages. This study fills in the literature gaps and explores the likely advantageous potential of the CPEC for the regional states. The study applied a convenient sampling technique for the data collection process. It used a mixed-method approach to gain scientific results, with a standardized questionnaire survey of 459 people (300 men and 159 women) from five major cities of Pakistan. The study results designate that residents believe that CPEC infrastructure projects will significantly improve residents' life quality through more job openings and community poverty reduction. Still, they raised their concerns regarding environmental protection issues in the region. The findings specified that residents had an optimistic approach to better educational productivity by adopting environment-oriented policies. Policymakers should establish new CPEC study centers in different areas, and investors should be encouraged to participate in the industrial sector. Officials can overwhelm community worries about environmental degradation. Government officials in both countries can utilize the findings to raise public awareness about CPEC's social, economic, cultural, mental wellbeing, and ecological implications.
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A phyllosphere bacterial strain EBL-06 was isolated from wheat leaves. The morphology, cultural characteristics, phospholipid fatty acids, physiological and antagonistic fungus activities of this strain were investigated. A phylogenetic tree was constructed by comparing with the published 16S rDNA sequences of the relevant bacteria. The results showed that the isolate EBL-06 was a strain of Paenibacillus polymyxa; this strain performed a high level of antagonistic fungus activity toward a broad spectrum of phytopathogens, such as Botrytis cinerea, Cladosporium cucumerinum, Fusarium spp. The isolate EBL-06 can grow well using monosodium glutamate wastewater (MGW) and potato wastewater (PW) as culture medium. The maximum yield of 6.5 x 10(9) CFU/mL of the isolate EBL-06 anti-fungus biocontrol agent was reached in 15 hr cultivation at 28 degrees C, pH 6.0-7.5 using the mixture of MGW and PW (1:9).
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Paenibacillus/metabolismo , Controle Biológico de Vetores/métodos , Glutamato de Sódio/metabolismo , Botrytis/crescimento & desenvolvimento , Cladosporium/crescimento & desenvolvimento , Fusarium/crescimento & desenvolvimento , Paenibacillus/classificação , Paenibacillus/genética , Filogenia , RNA Ribossômico 16S/genéticaRESUMO
Fungicides have been used extensively for controlling fungal pathogens of plants. However, little is known regarding the effects that fungicides upon the indigenous bacterial communities within the plant phyllosphere. The aims of this study were to assess the impact of fungicide enostroburin upon bacterial communities in wheat phyllosphere. Culture-independent methodologies of 16S rDNA clone library and 16S rDNA directed polymerase chain reaction with denaturing gradient gel electrophoresis (PCR-DGGE) were used for monitoring the change of bacterial community. The 16S rDNA clone library and PCR-DGGE analysis both confirmed the microbial community of wheat plant phyllosphere were predominantly of the gamma-Proteobacteria phyla. Results from PCR-DGGE analysis indicated a significant change in bacterial community structure within the phyllosphere following fungicide enostroburin application. Bands sequenced within control cultures were predominantly of Pseudomonas genus, but those bands sequenced in the treated samples were predominantly strains of Pantoea genus and Pseudomonas genus. Of interest was the appearance of two DGGE bands following fungicide treatment, one of which had sequence similarities (98%) to Pantoea sp. which might be a competitor of plant pathogens. This study revealed the wheat phyllosphere bacterial community composition and a shift in the bacterial community following fungicide enostroburin application.
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Fungicidas Industriais/farmacologia , Gammaproteobacteria/efeitos dos fármacos , Triticum/microbiologia , Sequência de Bases , DNA Bacteriano/química , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado , Gammaproteobacteria/genética , Gammaproteobacteria/crescimento & desenvolvimento , Dados de Sequência Molecular , Filogenia , Folhas de Planta/microbiologia , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/química , RNA Ribossômico 16S/genética , Alinhamento de SequênciaRESUMO
Metagenomic sequencing was used to reveal the dynamic changes in microbiota and the metabolic functions in corncob composting for preparing cultivation medium of Pleurotus ostreatus. Results showed that the changes of physicochemical properties lead to different dominant phylum at different stages of composting. Firmicutes replaced Proteobacteria as the dominant phylum at thermophilic stage. Correlation analysis indicated that the succession of microbiota was significantly affected by the C/N ratio, pH, temperature and organic matters in compost. The changes in community inevitably lead to the differences of metabolic functions. Metabolism analysis indicated that carbohydrate, lipid and amino acid metabolism were relatively higher in thermophilic stage. Conversely, the metabolism of starch, sucrose, galactose, ascorbate was mainly detected in the late stage. The metabolisms of different stages were driven by different microorganisms. Overall, these findings deepened our understanding of metabolic functions, and it is of great value to the metabolomics research of composting system.
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Phyllosphere harbors diverse microorganisms, which influence plant growth and health. In order to understand the extent to which environmental factors affect epiphytic microbial communities, we characterized microbial communities on leaves of three separate tree species present on the college campus, and also present within a forest park over two seasons. Quantitative PCR analysis showed the quantity of 16S rRNA genes was lower in May compared with October, while the abundances of functional genes (nifH and bacterial amoA genes) were extremely high in May. High-throughput sequencing revealed a large variation in the diversity and composition of bacterial and diazotrophic communities over the two seasons, and showed the abundance of functional genera, such as Nocardioides, Bacillus and Zoogloea were significantly elevated in May. In addition, xenobiotic biodegradation pathways of bacterial communities were clearly elevated in May. Network analysis showed the correlations between phyllospheric bacteria in May were more complex than that in October and showed greater negative correlations. These results were consistent in all tree species in this study. This study showed that phyllospheric bacteria varied greatly in different seasons, which implies that different growing seasons should be considered in the exploitation of the interactions between phyllospheric microorganisms and host plants.
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Ginkgo biloba , Pinus , Bactérias/genética , Filogenia , Folhas de Planta , RNA Ribossômico 16S/genética , Estações do AnoRESUMO
Using reclaimed wastewater for crop irrigation is a practical alternative to discharge wastewater treatment plant effluents into surface waters. However, biofouling has been identified as a major contributor to emitter clogging in drip irrigation systems distributing reclaimed wastewater. Little is known about the biofilm structure and its influence on clogging in the drip emitter flow path. This study was first to investigate the microbial characteristics of mature biofilms present in the emitters and the effect of flow path structures on the biofilm microbial communities. The analysis of biofilm matrix structure using a scanning electron microscopy (SEM) revealed that particles in the matrix of the biofilm coupled extracellular polysaccharides (EPS) and formed sediment in the emitter flow path. Analysis of biofilm mass including protein, polysaccharide, and phospholipid fatty acids (PLFAs) showed that emitter flow path style influenced biofilm community structure and diversity. The correlations of biofilm biomass and discharge reduction after 360 h irrigation were computed and suggest that PFLAs provide the best correlation coefficient. Comparatively, the emitter with the unsymmetrical dentate structure and shorter flow path (Emitter C) had the best anti-clogging capability. By optimizing the dentate structure, the internal flow pattern within the flow path could be enhanced as an important method to control the biofilm within emitter flow path. This study established electron microscope techniques and biochemical microbial analysis methods that may provide a framework for future emitter biofilm studies.