RESUMEN
One of the main challenges in food microbiology is to prevent the risk of outbreaks by avoiding the distribution of food contaminated by bacteria. This requires constant monitoring of the circulating strains throughout the food production chain. Bacterial genomes contain signatures of natural evolution and adaptive markers that can be exploited to better understand the behavior of pathogen in the food industry. The monitoring of foodborne strains can therefore be facilitated by the use of these genomic markers capable of rapidly providing essential information on isolated strains, such as the source of contamination, risk of illness, potential for biofilm formation, and tolerance or resistance to biocides. The increasing availability of large genome datasets is enhancing the understanding of the genetic basis of complex traits such as host adaptation, virulence, and persistence. Genome-wide association studies have shown very promising results in the discovery of genomic markers that can be integrated into rapid detection tools. In addition, machine learning has successfully predicted phenotypes and classified important traits. Genome-wide association and machine learning tools have therefore the potential to support decision-making circuits intending at reducing the burden of foodborne diseases. The aim of this chapter review is to provide knowledge on the use of these two methods in food microbiology and to recommend their use in the field.
Asunto(s)
Bacterias , Microbiología de Alimentos , Enfermedades Transmitidas por los Alimentos , Estudio de Asociación del Genoma Completo , Aprendizaje Automático , Humanos , Bacterias/genética , Enfermedades Transmitidas por los Alimentos/microbiología , Enfermedades Transmitidas por los Alimentos/genética , Variación Genética , Genoma Bacteriano , Estudio de Asociación del Genoma Completo/métodos , FenotipoRESUMEN
Foodborne pathogens are responsible for foodborne diseases and food poisoning and thus pose a great threat to food safety. These microorganisms can adhere to surface and form a biofilm composed of an extracellular matrix. This matrix protects bacterial cells from industrial environmental stress factors such as cleaning and disinfection operations. Moreover, during these environmental stresses, many bacterial species can be entered in a viable but nonculturable (VBNC) state. VBNC cells are characterized by an active metabolism and a loss of cultivability on conventional bacteriological agar. This leads to an underestimation of total viable cells in environmental samples and thus may pose a risk for public health. In this chapter, we present a method to detect viable population of foodborne pathogens in industrial environmental samples using a molecular method combining propidium monoazide (PMA) and quantitative PCR (qPCR) and a fluorescence microscopic method associated with the LIVE/DEAD BacLight™ viability stain.
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Azidas , Microbiología de Alimentos , Viabilidad Microbiana , Propidio , Reacción en Cadena en Tiempo Real de la Polimerasa , Microbiología de Alimentos/métodos , Azidas/química , Propidio/análogos & derivados , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Bacterias/genética , Bacterias/aislamiento & purificación , Enfermedades Transmitidas por los Alimentos/microbiología , Microscopía Fluorescente/métodos , HumanosRESUMEN
Properly using controllable atmospheric containers can facilitate investigations of the survival abilities and physiological states of key and emerging-foodborne pathogens under recreated applicable food processing environmental conditions. Notably, saturated salt solutions can efficiently control relative humidity in airtight containers. This chapter describes a practical experimental setup, with necessary prerequisites for exposing foodborne pathogens to simulated and relevant food processing environmental conditions. Subsequent analyses for studying cell physiology will also be suggested.
Asunto(s)
Manipulación de Alimentos , Microbiología de Alimentos , Manipulación de Alimentos/métodos , Enfermedades Transmitidas por los Alimentos/microbiología , Viabilidad Microbiana , Bacterias/crecimiento & desarrollo , HumanosRESUMEN
Although MALDI-TOF mass spectrometry (MS) is considered as the gold standard for rapid and cost-effective identification of microorganisms in routine laboratory practices, its capability for antimicrobial resistance (AMR) detection has received limited focus. Nevertheless, recent studies explored the predictive performance of MALDI-TOF MS for detecting AMR in clinical pathogens when machine learning techniques are applied. This chapter describes a routine MALDI-TOF MS workflow for the rapid screening of AMR in foodborne pathogens, with Campylobacter spp. as a study model.
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Campylobacter , Farmacorresistencia Bacteriana , Aprendizaje Automático , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Campylobacter/efectos de los fármacos , Antibacterianos/farmacología , Humanos , Microbiología de Alimentos/métodos , Pruebas de Sensibilidad Microbiana/métodos , Enfermedades Transmitidas por los Alimentos/microbiología , Bacterias/efectos de los fármacosRESUMEN
When submitted to environmental stresses, bacteria can modulate its fatty acid composition of membrane phospholipids in order to optimize membrane fluidity. Characterization of bacterial membrane fatty acid profiles is thus an interesting indicator of cellular physiological state. The methodology described here aims to improve the recovering of biofilm cells for the characterization of their fatty acid profiles. The saponification reagent is directly applied on the whole biofilm before the removal of cells from the inert surface. In this way, maximum of the cells and their fatty acids can be recovered from the deepest layers of the biofilm.
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Biopelículas , Membrana Celular , Ácidos Grasos , Biopelículas/crecimiento & desarrollo , Ácidos Grasos/metabolismo , Membrana Celular/metabolismo , Bacterias/metabolismo , Fosfolípidos/metabolismo , Fluidez de la MembranaRESUMEN
Like most microorganisms, important foodborne pathogenic bacteria, such as Salmonella enterica, Listeria monocytogenes, and several others as well, can attach to surfaces, of either abiotic or biotic nature, and create biofilms on them, provided the existence of supportive environmental conditions (e.g., permissive growth temperature, adequate humidity, and nutrient presence). Inside those sessile communities, the enclosed bacteria typically present a gene expression profile that differs from the one that would be displayed by the same cells growing planktonically in liquid media (free-swimming cells). This altered gene expression has important consequences on cellular physiology and behavior, including stress tolerance and induction of virulence. In this chapter, the methodology to use reverse transcription-quantitative polymerase chain reaction (RT-qPCR) to monitor and comparatively quantify expression changes in preselected genes of bacteria between planktonic and biofilm growth modes is presented.
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Biopelículas , Plancton , Biopelículas/crecimiento & desarrollo , Plancton/genética , Regulación Bacteriana de la Expresión Génica , Microbiología de Alimentos , Perfilación de la Expresión Génica/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Bacterias/genética , Listeria monocytogenes/genética , Listeria monocytogenes/fisiología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodosRESUMEN
Unveiling the strategies of bacterial adaptation to stress constitute a challenging area of research. The understanding of mechanisms governing emergence of resistance to antimicrobials is of particular importance regarding the increasing threat of antibiotic resistance on public health worldwide. In the last decades, the fast democratization of sequencing technologies along with the development of dedicated bioinformatical tools to process data offered new opportunities to characterize genomic variations underlying bacterial adaptation. Thereby, research teams have now the possibility to dive deeper in the deciphering of bacterial adaptive mechanisms through the identification of specific genetic targets mediating survival to stress. In this chapter, we proposed a step-by-step bioinformatical pipeline enabling the identification of mutational events underlying biocidal stress adaptation associated with antimicrobial resistance development using Escherichia marmotae as an illustrative model.
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Biología Computacional , Genoma Bacteriano , Genómica , Mutación , Genómica/métodos , Biología Computacional/métodos , Bacterias/genética , Bacterias/efectos de los fármacos , Farmacorresistencia Bacteriana/genética , Antibacterianos/farmacología , Programas Informáticos , Secuenciación de Nucleótidos de Alto Rendimiento/métodosRESUMEN
Next-generation sequencing revolutionized food safety management these last years providing access to a huge quantity of valuable data to identify, characterize, and monitor bacterial pathogens on the food chain. Shotgun metagenomics emerged as a particularly promising approach as it enables in-depth taxonomic profiling and functional investigation of food microbial communities. In this chapter, we provide a comprehensive step-by-step bioinformatical workflow to characterize bacterial ecology and resistome composition from metagenomic short-reads obtained by shotgun sequencing.
Asunto(s)
Bacterias , Biología Computacional , Microbiología de Alimentos , Secuenciación de Nucleótidos de Alto Rendimiento , Metagenómica , Metagenómica/métodos , Biología Computacional/métodos , Microbiología de Alimentos/métodos , Bacterias/genética , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Metagenoma , Microbiota/genéticaRESUMEN
Hi-C and 3C-seq are powerful tools to study the 3D genomes of bacteria and archaea, whose small cell sizes and growth conditions are often intractable to detailed microscopic analysis. However, the circularity of prokaryotic genomes requires a number of tricks for Hi-C/3C-seq data analysis. Here, I provide a practical guide to use the HiC-Pro pipeline for Hi-C/3C-seq data obtained from prokaryotes.
Asunto(s)
Genoma Bacteriano , Programas Informáticos , Genómica/métodos , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Células Procariotas/metabolismo , Genoma Arqueal , Archaea/genética , Bacterias/genética , Biología Computacional/métodos , Análisis de DatosRESUMEN
Noni fruit has an unpleasant flavour but is highly bioactive. Therefore, it is necessary to clarify the effect of temperature regulation on quality of fermented noni fruit. In the present study, the formation of flavours, amino acid profiles, and iridoid glycosides during noni fruit fermentation at different temperatures were investigated. We initially found that different temperatures affected core microbial communities. The general evolutionary trends of Acetobacter and Gluconobacter were influenced by different temperatures. Furthermore, high temperature helped maintain low octanoic and hexanoic acids. Subsequently, we found that high temperature improved total amino acids and iridoid glycosides. The correlation network analysis revealed that bacterial communities impacted the quality (volatile flavours, amino acid profiles, and iridoid glycosides) of fermented noni fruit. Overall, altering the temperature induced variations in microbial communities and quality during the noni fruit fermentation process. These results are instrumental in the pursuit of quality control in natural fermentation processes.
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Aminoácidos , Bacterias , Fermentación , Frutas , Glicósidos Iridoides , Microbiota , Morinda , Temperatura , Frutas/química , Frutas/metabolismo , Frutas/microbiología , Aminoácidos/metabolismo , Aminoácidos/análisis , Bacterias/metabolismo , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Morinda/química , Morinda/metabolismo , Glicósidos Iridoides/metabolismo , Glicósidos Iridoides/análisis , Glicósidos Iridoides/química , Compuestos Orgánicos Volátiles/metabolismo , Compuestos Orgánicos Volátiles/química , Aromatizantes/metabolismo , Aromatizantes/químicaRESUMEN
Application of microbial-based biopreparations as a pre-harvest strategy offers a method to obtain sustainable agricultural practices and could be an important approach for advancing food science, promoting sustainability, and meeting global food market demands. The impact of a bacterial-fungal biopreparation mixture on soil-plant-microbe interactions, fruit chemical composition and yield of 7 raspberry clones was investigated by examining the structural and functional profiles of microbial communities within leaves, fruits, and soil. Biopreparation addition caused the enhancement of the microbiological utilization of specific compounds, such as d-mannitol, relevant in plant-pathogen interactions and overall plant health. The biopreparation treatment positively affected the nitrogen availability in soil (9-160%). The analysis of plant stress marker enzymes combined with the evaluation of fruit quality and chemical properties highlight changes inducted by the pre-harvest biopreparation application. Chemical analyses highlight biopreparations' role in soil and fruit quality improvement, promoting sustainable agriculture. This effect was dependent on tested clones, showing increase of soluble solid content in fruits, concentration of polyphenols or the sensory quality of the fruits. The results of the next-generation sequencing indicated increase in the effective number of bacterial species after biopreparation treatment. The network analysis showed stimulating effect of biopreparation on microbial communities by enhancing microbial interactions (increasing the number of network edges up to 260%) of and affecting the proportions of mutual relationships between both bacteria and fungi. These findings show the potential of microbial-based biopreparation in enhancing raspberry production whilst promoting sustainable practices and maintaining environmental homeostasis and giving inshght in holistic understanding of microbial-based approaches for advancing food science monitoring.
Asunto(s)
Bacterias , Frutas , Hongos , Rubus , Microbiología del Suelo , Suelo , Frutas/química , Frutas/microbiología , Frutas/metabolismo , Rubus/química , Rubus/microbiología , Rubus/metabolismo , Rubus/crecimiento & desarrollo , Suelo/química , Bacterias/clasificación , Bacterias/metabolismo , Bacterias/genética , Bacterias/aislamiento & purificación , Bacterias/crecimiento & desarrollo , Hongos/metabolismo , Hongos/crecimiento & desarrollo , Agricultura , MicrobiotaRESUMEN
In this study, we investigated how different proportions blends of Rhamnogalacturonan-I pectic polysaccharides and hesperidin impact the gut microbiota and metabolites using an in vitro simulated digestion and fermentation model. The results indicated that both of them could modulate the gut microbiota and produce beneficial metabolites. However, their blends in particular proportions (such as 1:1) exhibited remarkable synergistic effects on modulating the intestinal microenvironment, surpassing the effects observed with individual components. Specifically, these blends could benefit the host by increasing short-chain fatty acids production (such as acetate), improving hesperidin bioavailability, producing more metabolites (such as hesperetin, phenolic acids), and promoting the growth of beneficial bacteria. This synergistic and additive effect was inseparable from the role of gut microbiota. Certain beneficial bacteria, such as Blautia, Faecalibacterium, and Prevotella, exhibited strong preferences for those blends, thereby contributing to host health through participating in carbohydrate and flavonoid metabolism.
Asunto(s)
Bacterias , Microbioma Gastrointestinal , Hesperidina , Pectinas , Hesperidina/farmacología , Hesperidina/metabolismo , Microbioma Gastrointestinal/efectos de los fármacos , Bacterias/metabolismo , Bacterias/genética , Bacterias/efectos de los fármacos , Bacterias/clasificación , Bacterias/aislamiento & purificación , Humanos , Pectinas/metabolismo , Pectinas/química , Pectinas/farmacología , Fermentación , Polisacáridos/farmacología , Polisacáridos/metabolismo , Polisacáridos/química , Ácidos Grasos Volátiles/metabolismo , Digestión , Modelos BiológicosRESUMEN
Airborne microorganisms (AM) have significant environmental and health implications. Extensive studies have been conducted to investigate the factors influencing the composition and diversity of AM. However, the knowledge of AM with anthropogenic activities has not reach a consensus. In this study, we took advantage of the dramatic decline of outdoor anthropogenic activities resulting from COVID-19 lockdown to reveal their associations. We collected airborne particulate matter before and during the lockdown period in two cities. The results showed that it was fungal diversity and communities but not bacteria obviously different between pre-lockdown and lockdown samples, suggesting that airborne fungi were more susceptible to anthropogenic activities than bacteria. However, after the implementation of lockdown, the co-occurrence networks of both bacterial and fungal community became more complex, which might be due to the variation of microbial sources. Furthermore, Mantel test and correlation analysis showed that air pollutants also partly contributed to microbial alterations. Airborne fungal community was more affected by air pollutants than bacterial community. Notably, some human pathogens like Nigrospora and Arthrinium were negatively correlated with air pollutants. Overall, our study highlighted the more impacts of anthropogenic activities on airborne fungal community than bacterial community and advanced the understanding of associations between anthropogenic activities and AM.
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Microbiología del Aire , Contaminantes Atmosféricos , Bacterias , Monitoreo del Ambiente , Hongos , Bacterias/clasificación , Contaminantes Atmosféricos/análisis , Material Particulado/análisis , COVID-19 , Humanos , ChinaRESUMEN
Because of the recent widespread usage of antibiotics, the acquisition and dissemination of antibiotic-resistance genes (ARGs) were prevalent in the majority of habitats. Generally, the biological wastewater treatment processes used in wastewater treatment plants have a limited efficiencies of antibiotics resistant bacteria (ARB) disinfection and ARGs degradation and even promote the proliferation of ARGs. Problematically, ARB and ARGs in effluent pose potential risks if they are not further treated. Photocatalytic oxidation is considered a promising disinfection technology, where the photocatalytic process generates many free radicals that enhance the interaction between light and deoxyribonucleic acid (DNA) for ARB elimination and subsequent degradation of ARGs. This review aims to illustrate the progress of photocatalytic oxidation technology for removing antibiotics resistant (AR) from wastewater in recent years. We discuss the sources and transfer of ARGs in wastewater. The overall removal efficiencies of ultraviolet radiation (UV)/chlorination, UV/ozone, UV/H2O2, and UV/sulfate-radical based system for ARB and ARGs, as well as the experimental parameters and removal mechanisms, are systematically discussed. The contribution of photocatalytic materials based on TiO2 and g-C3N4 to the inactivation of ARB and degradation of ARGs is highlighted, producing many free radicals to attack ARB and ARGs while effectively limiting the horizontal gene transfer (HGT) in wastewater. Finally, based on the reviewed studies, future research directions are proposed to realize specific photocatalytic oxidation technology applications and overcome current challenges.
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Eliminación de Residuos Líquidos , Aguas Residuales , Aguas Residuales/química , Eliminación de Residuos Líquidos/métodos , Bacterias , Desinfección/métodos , Farmacorresistencia Bacteriana/genética , Rayos Ultravioleta , Purificación del Agua/métodosRESUMEN
Arsenic (As) methylation in soils affects the environmental behavior of As, excessive accumulation of dimethylarsenate (DMA) in rice plants leads to straighthead disease and a serious drop in crop yield. Understanding the mobility and transformation of methylated arsenic in redox-changing paddy fields is crucial for food security. Here, soils including un-arsenic contaminated (N-As), low-arsenic (L-As), medium-arsenic (M-As), and high-arsenic (H-As) soils were incubated under continuous anoxic, continuous oxic, and consecutive anoxic/oxic treatments respectively, to profile arsenic methylating process and microbial species involved in the As cycle. Under anoxic-oxic (A-O) treatment, methylated arsenic was significantly increased once oxygen was introduced into the incubation system. The methylated arsenic concentrations were up to 2-24 times higher than those in anoxic (A), oxic (O), and oxic-anoxic (O-A) treatments, under which arsenic was methylated slightly and then decreased in all four As concentration soils. In fact, the most plentiful arsenite S-adenosylmethionine methyltransferase genes (arsM) contributed to the increase in As methylation. Proteobacteria (40.8%-62.4%), Firmicutes (3.5%-15.7%), and Desulfobacterota (5.3%-13.3%) were the major microorganisms related to this process. These microbial increased markedly and played more important roles after oxygen was introduced, indicating that they were potential keystone microbial groups for As methylation in the alternating anoxic (flooding) and oxic (drainage) environment. The novel findings provided new insights into the reoxidation-driven arsenic methylation processes and the model could be used for further risk estimation in periodically flooded paddy fields.
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Arsénico , Oryza , Microbiología del Suelo , Contaminantes del Suelo , Suelo , Arsénico/análisis , Contaminantes del Suelo/análisis , Metilación , Suelo/química , Microbiota , Oxidación-Reducción , Bacterias/metabolismoRESUMEN
Woodchip bioreactors are an eco-friendly technology for removing nitrogen (N) pollution. However, there needs to be more clarity regarding the dissolved organic matter (DOM) characteristics and bacterial community succession mechanisms and their association with the N removal performance of bioreactors. The laboratory woodchip bioreactors were continuously operated for 360 days under three influent N level treatments, and the results showed that the average removal rate of TN was 45.80 g N/(m3·day) when the influent N level was 100 mg N/L, which was better than 10 mg N/L and 50 mg N/L. Dynamic succession of bacterial communities in response to influent N levels and DOM characteristics was an important driver of TN removal rates. Medium to high N levels enriched a copiotroph bacterial module (Module 1) detected by network analysis, including Phenylobacterium, Xanthobacteraceae, Burkholderiaceae, Pseudomonas, and Magnetospirillaceae, carrying N-cycle related genes for denitrification and ammonia assimilation by the rapid consumption of DOM. Such a process can increase carbon limitation to stimulate local organic carbon decomposition to enrich oligotrophs with fewer N-cycle potentials (Module 2). Together, this study reveals that the compositional change of DOM and bacterial community succession are closely related to N removal performance, providing an ecological basis for developing techniques for N-rich effluent treatment.
Asunto(s)
Bacterias , Reactores Biológicos , Nitrógeno , Eliminación de Residuos Líquidos , Reactores Biológicos/microbiología , Nitrógeno/análisis , Bacterias/metabolismo , Eliminación de Residuos Líquidos/métodos , MicrobiotaRESUMEN
In this study, the effects of different salinity gradients and addition of compatible solutes on anaerobic treated effluent water qualities, sludge characteristics and microbial communities were investigated. The increase in salinity resulted in a decrease in particle size of the granular sludge, which was concentrated in the range of 0.5-1.0 mm. The content of EPS (extracellular polymeric substances) in the granular sludge gradually increased with increasing salinity and the addition of betaine (a typical compatible solute). Meanwhile, the microbial community structure was significantly affected by salinity, with high salinity reducing the diversity of bacteria. At higher salinity, Patescibacteria and Proteobacteria gradually became the dominant phylum, with relative abundance increasing to 13.53% and 12.16% at 20 g/L salinity. Desulfobacterota and its subordinate Desulfovibrio, which secrete EPS in large quantities, dominated significantly after betaine addition.Their relative abundance reached 13.65% and 7.86% at phylum level and genus level. The effect of these changes on the treated effluent was shown as the average chemical oxygen demand (COD) removal rate decreased from 82.10% to 79.71%, 78.01%, 68.51% and 64.55% when the salinity gradually increased from 2 g/L to 6, 10, 16 and 20 g/L. At the salinity of 20 g/L, average COD removal increased to 71.65% by the addition of 2 mmol/L betaine. The gradient elevated salinity and the exogenous addition of betaine played an important role in achieving stability of the anaerobic system in a highly saline environment, which provided a feasible strategy for anaerobic treatment of organic saline wastewater.
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Betaína , Salinidad , Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Aguas Residuales , Betaína/metabolismo , Aguas del Alcantarillado/microbiología , Eliminación de Residuos Líquidos/métodos , Aguas Residuales/química , Anaerobiosis , Microbiota/efectos de los fármacos , Bacterias/metabolismo , Bacterias/efectos de los fármacosRESUMEN
Salinity was considered to have effects on the characteristics, performance microbial communities of aerobic granular sludge. This study investigated granulation process with gradual increase of salt under different gradients. Two identical sequencing batch reactors were operated, while the influent of Ra and Rb was subjected to stepwise increments of NaCl concentrations (0-4 g/L and 0-10 g/L). The presence of filamentous bacteria may contribute to granules formed under lower salinity conditions, potentially leading to granules fragmentation. Excellent removal efficiency achieved in both reactors although there was a small accumulation of nitrite in Rb at later stages. The removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) in Ra were 95.31%, 93.70% and 88.66%, while the corresponding removal efficiencies in Rb were 94.19%, 89.79% and 80.74%. Salinity stimulated extracellular polymeric substances (EPS) secretion and enriched EPS producing bacteria to help maintain the integrity and stability of the aerobic granules. Heterotrophic nitrifying bacteria were responsible for NH4+-N and NO2--N oxidation of salinity systems and large number of denitrifying bacteria were detected, which ensure the high removal efficiency of TN in the systems.
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Reactores Biológicos , Nitrógeno , Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Eliminación de Residuos Líquidos/métodos , Reactores Biológicos/microbiología , Aguas del Alcantarillado/microbiología , Fósforo/metabolismo , Salinidad , Cloruro de Sodio , Bacterias/metabolismo , Microbiota , Análisis de la Demanda Biológica de OxígenoRESUMEN
The multi-soil-layering (MSL) systems is an emerging solution for environmentally-friendly and cost-effective treatment of decentralized rural domestic wastewater. However, the role of the seemingly simple permeable layer has been overlooked, potentially holding the breakthroughs or directions to addressing suboptimal nitrogen removal performance in MSL systems. In this paper, the mechanism among diverse substrates (zeolite, green zeolite and biological ceramsite) coupled microorganisms in different systems (activated bacterial powder and activated sludge) for rural domestic wastewater purification was investigated. The removal efficiencies performed by zeolite coupled with microorganisms within 3 days were 93.8% for COD, 97.1% for TP, and 98.8% for NH4+-N. Notably, activated sludge showed better nitrification and comprehensive performance than specialized nitrifying bacteria powder. Zeolite attained an impressive 89.4% NH4+-N desorption efficiency, with a substantive fraction of NH4+-N manifesting as exchanged ammonium. High-throughput 16S rRNA gene sequencing revealed that aerobic and parthenogenetic anaerobic bacteria dominated the reactor, with anaerobic bacteria conspicuously absent. And the heterotrophic nitrification-aerobic denitrification (HN-AD) process was significant, with the presence of denitrifying phosphorus-accumulating organisms (DPAOs) for simultaneous nitrogen and phosphorus removal. This study not only raises awareness about the importance of the permeable layer and enhances comprehension of the HN-AD mechanism in MSL systems, but also provides valuable insights for optimizing MSL system construction, operation, and rural domestic wastewater treatment.
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Eliminación de Residuos Líquidos , Eliminación de Residuos Líquidos/métodos , Nitrificación , Nitrógeno/metabolismo , Suelo/química , Desnitrificación , Aguas Residuales/química , Aguas del Alcantarillado/microbiología , Microbiología del Suelo , Zeolitas/química , Fósforo/metabolismo , Reactores Biológicos/microbiología , Bacterias/metabolismoRESUMEN
Deploying anti-CRISPR proteins is a potent strategy used by phages to inhibit bacterial CRISPR-Cas defense. In a new Nature paper, Trost et al.1 discover and characterize an exciting anti-CRISPR mechanism with possible implications beyond this microscopic arms race.