Application and biomolecular monitoring of psychrophilic anaerobic digestion

Thirteen anaerobic hybrid expanded granular sludge bed-anaerobic filter bioreactors were used for psychrophilic (15–18 °C) anaerobic digestion of a variety of synthetic and non-synthetic wastewaters, including: food-processing, dairy, aromatic- and aliphatic-containing and brewery discharges. Specific methanogenic activity assays were employed to assess temporal physiological activity dynamics. Terminal restriction fragment length polymorphism genetic fingerprinting and fluorescent in situ hybridization were used to monitor shifts in the structure of the microbial communities in the bioreactors in response to operating conditions. Treatment efficiencies obtained were comparable to previous mesophilic (37 °C) trials. Methanogenic activity developed under psychrophilic conditions and putative psychrophilic populations were detected within otherwise psychrotolerant mesophilic communities. Shifts in the population structure of archaeal (methanogenic) communities were more indicative of process disruption than bacterial communities. Biomolecular techniques were demonstrated as valuable tools for anaerobic wastewater treatment plant monitoring.

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Effects of Rifaximin on Luminal and Wall-Adhered Gut Commensal Microbiota in Mice

International Journal of Molecular Sciences ◽

10.3390/ijms22020500 ◽

2021 ◽

Vol 22 (2) ◽

pp. 500

Author(s):

Marina Ferrer ◽

Mònica Aguilera ◽

Vicente Martinez

Keyword(s):

Fluorescent In Situ Hybridization ◽

Fragment Length Polymorphism ◽

Functional Gastrointestinal Disorders ◽

Antibacterial Properties ◽

Broad Spectrum Antibiotic ◽

Commensal Microbiota ◽

Bacterial Biodiversity ◽

Rule Out

Rifaximin is a broad-spectrum antibiotic that ameliorates symptomatology in inflammatory/functional gastrointestinal disorders. We assessed changes in gut commensal microbiota (GCM) and Toll-like receptors (TLRs) associated to rifaximin treatment in mice. Adult C57BL/6NCrl mice were treated (7/14 days) with rifaximin (50/150 mg/mouse/day, PO). Luminal and wall-adhered ceco-colonic GCM were characterized by fluorescent in situ hybridization (FISH) and microbial profiles determined by terminal restriction fragment length polymorphism (T-RFLP). Colonic expression of TLR2/3/4/5/7 and immune-related markers was assessed (RT-qPCR). Regardless the period of treatment or the dose, rifaximin did not alter total bacterial counts or bacterial biodiversity. Only a modest increase in Bacteroides spp. (150 mg/1-week treatment) was detected. In control conditions, only Clostridium spp. and Bifidobacterium spp. were found attached to the colonic epithelium. Rifaximin showed a tendency to favour their adherence after a 1-week, but not 2-week, treatment period. Minor up-regulation in TLRs expression was observed. Only the 50 mg dose for 1-week led to a significant increase (by 3-fold) in TLR-4 expression. No changes in the expression of immune-related markers were observed. Rifaximin, although its antibacterial properties, induces minor changes in luminal and wall-adhered GCM in healthy mice. Moreover, no modulation of TLRs or local immune systems was observed. These findings, in normal conditions, do not rule out a modulatory role of rifaximin in inflammatory and or dysbiotic states of the gut.

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Time-series genome-centric analysis unveils bacterial response to operational disturbance in activated sludge

10.1101/565770 ◽

2019 ◽

Cited By ~ 1

Author(s):

María Victoria Pérez ◽

Leandro D. Guerrero ◽

Esteban Orellana ◽

Eva L. Figuerola ◽

Leonardo Erijman

Keyword(s):

Growth Rate ◽

Time Series ◽

Wastewater Treatment ◽

Activated Sludge ◽

Microbial Communities ◽

Wastewater Treatment Plant ◽

Treatment Plant ◽

Operating Conditions ◽

The Face

ABSTRACTUnderstanding ecosystem response to disturbances and identifying the most critical traits for the maintenance of ecosystem functioning are important goals for microbial community ecology. In this study, we used 16S rRNA amplicon sequencing and metagenomics to investigate the assembly of bacterial populations in a full-scale municipal activated sludge wastewater treatment plant over a period of three years, including a period of nine month of disturbance, characterized by short-term plant shutdowns. Following the reconstruction of 173 metagenome-assembled genomes, we assessed the functional potential, the number of rRNA gene operons and thein situgrowth rate of microorganisms present throughout the time series. Operational disturbances caused a significant decrease in bacteria with a single copy of the ribosomal RNA (rrn) operon. Despite only moderate differences in resource availability, replication rates were distributed uniformly throughout time, with no differences between disturbed and stable periods. We suggest that the length of the growth lag phase, rather than the growth rate, as the primary driver of selection under disturbed conditions. Thus, the system could maintain its function in the face of disturbance by recruiting bacteria with the capacity to rapidly resume growth under unsteady operating conditions.IMPORTANCEIn this work we investigated the response of microbial communities to disturbances in a full-scale activated sludge wastewater treatment plant over a time-scale that included periods of stability and disturbance. We performed a genome-wide analysis, which allowed us the direct estimation of specific cellular traits, including the rRNA operon copy number and the in situ growth rate of bacteria. This work builds upon recent efforts to incorporate growth efficiency for the understanding of the physiological and ecological processes shaping microbial communities in nature. We found evidence that would suggest that activated sludge could maintain its function in the face of disturbance by recruiting bacteria with the capacity to rapidly resume growth under unsteady operating conditions. This paper provides relevant insights into wastewater treatment process, and may also reveal a key role for growth traits in the adaptive response of bacteria to unsteady environmental conditions.

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Selection of inocula conditioning methodologies for the anaerobic digestion of food waste

Revista Facultad de Ingeniería Universidad de Antioquia ◽

10.17533/udea.redin.20190510 ◽

2019 ◽

pp. 9-18

Author(s):

Brayan Alexis Parra Orobio ◽

Melkin Nieto Mendoza ◽

Diego Rivera Henao ◽

Pablo Cesar Manyoma Vélasquez ◽

Patricia Torres Lozada

Keyword(s):

Anaerobic Digestion ◽

Latin American ◽

Food Waste ◽

Multicriteria Analysis ◽

Granular Sludge ◽

Methanogenic Activity ◽

Significant Events ◽

Hierarchy Process ◽

Selection Of ◽

Main Strategy

Food waste (FW) has a high potential for use in biological processes such as anaerobic digestion (AD), especially due to its high content of biodegradable organic matter. To inoculate the reactors, sludge is usually used. The sludge should ideally have good sedimentation and specific methanogenic activity (SMA), which is typical for granular sludge. However, in a Latin American context, the most available and accessible sludges are flocculants with low sedimentation and SMA. Applying technological surveillance between 1975 and 2017, using multicriteria analysis techniques such as analytical hierarchy process (AHP), and consulting with international and national experts, we observed that there were few studies, compared to published studies on the substrates that focused on improving inoculum quality through conditioning to improve its characteristics and maximize methane production. The inoculum-conditioning methodologies identified were grouped into five categories, being the main strategy the addition of nutrients followed by anaerobic digestion with an easily degradable substrate. However, extension of technological surveillance is recommended by incorporating the results published from significant events in the field of anaerobic digestion, such as the Latin American Workshop and Symposium on Anaerobic Digestion and the World Congress on Anaerobic Digestion.

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Time Series Genome-Centric Analysis Unveils Bacterial Response to Operational Disturbance in Activated Sludge

mSystems ◽

10.1128/msystems.00169-19 ◽

2019 ◽

Vol 4 (4) ◽

Cited By ~ 4

Author(s):

María Victoria Pérez ◽

Leandro D. Guerrero ◽

Esteban Orellana ◽

Eva L. Figuerola ◽

Leonardo Erijman

Keyword(s):

Growth Rate ◽

Time Series ◽

Wastewater Treatment ◽

Activated Sludge ◽

Wastewater Treatment Plant ◽

Treatment Plant ◽

Full Scale ◽

Operating Conditions ◽

Lag Phase

ABSTRACT Understanding ecosystem response to disturbances and identifying the most critical traits for the maintenance of ecosystem functioning are important goals for microbial community ecology. In this study, we used 16S rRNA amplicon sequencing and metagenomics to investigate the assembly of bacterial populations in a full-scale municipal activated sludge wastewater treatment plant over a period of 3 years, including a 9-month period of disturbance characterized by short-term plant shutdowns. Following the reconstruction of 173 metagenome-assembled genomes, we assessed the functional potential, the number of rRNA gene operons, and the in situ growth rate of microorganisms present throughout the time series. Operational disturbances caused a significant decrease in bacteria with a single copy of the rRNA (rrn) operon. Despite moderate differences in resource availability, replication rates were distributed uniformly throughout time, with no differences between disturbed and stable periods. We suggest that the length of the growth lag phase, rather than the growth rate, is the primary driver of selection under disturbed conditions. Thus, the system could maintain its function in the face of disturbance by recruiting bacteria with the capacity to rapidly resume growth under unsteady operating conditions. IMPORTANCE Disturbance is a key determinant of community assembly and dynamics in natural and engineered ecosystems. Microbiome response to disturbance is thought to be influenced by bacterial growth traits and life history strategies. In this time series observational study, the response to disturbance of microbial communities in a full-scale activated sludge wastewater treatment plant was assessed by computing specific cellular traits of genomes retrieved from metagenomes. It was found that the genomes observed in disturbed periods have more copies of the rRNA operon than genomes observed in stable periods, whereas the in situ mean relative growth rates of bacteria present during stable and disturbed periods were indistinguishable. From these intriguing observations, we infer that the length of the lag phase might be a growth trait that affects the microbial response to disturbance. Further exploration of this hypothesis could contribute to better understanding of the adaptive response of microbiomes to unsteady environmental conditions.

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Microbial succession of glycogen accumulating organisms in an anaerobic-aerobic membrane bioreactor with no phosphorus removal

Water Science & Technology ◽

10.2166/wst.2006.368 ◽

2006 ◽

Vol 54 (1) ◽

pp. 29-37 ◽

Cited By ~ 10

Author(s):

M.-T. Wong ◽

W.-T. Liu

Keyword(s):

Phosphorus Removal ◽

Membrane Bioreactor ◽

Fragment Length Polymorphism ◽

Operating Conditions ◽

Biological Phosphorus Removal ◽

Microbial Succession ◽

Solid Residence Time ◽

Biological Phosphorus ◽

Quantitative Fluorescence

The succession of glycogen accumulating organisms (GAOs) has been observed in an acetate-fed, anaerobic-aerobic sequencing membrane bioreactor (MBR) operated for 260 days without enhanced biological phosphorus removal (EBPR) activity. Semi-quantitative fluorescence in situ hybridization results showed that a gammaproteobacterial lineage GB frequently observed in EBPR processes was initially the numerically dominant species (50–66% of total cells) of the GAO in the MBR from day 1 to day 38. During this period, succession of two different subgroups of group GB was also observed. On day 85 onward, a population shift from GB group to ‘Defluvicoccus’-related tetrad-forming organisms (TFO) occurred. This microbial succession was suspected to be related to the applied operating conditions (long hydraulic retention time and long solid residence time) which favored the proliferation of ‘Defluvicoccus’-related TFO rather than the GB group. Application of terminal restriction fragment length polymorphism on selected samples further revealed that the microbial diversity of the seeding sludge as determined by the number of terminal restriction fragments was higher than that of sludge samples taken after day 85.

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Genetic and Cytogenetic Mapping of DMI1, DMI2, and DMI3 Genes of Medicago truncatula Involved in Nod Factor Transduction, Nodulation, and Mycorrhization

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2002.15.11.1108 ◽

2002 ◽

Vol 15 (11) ◽

pp. 1108-1118 ◽

Cited By ~ 41

Author(s):

Jean-Michel Ané ◽

Julien Lévy ◽

Philippe Thoquet ◽

Olga Kulikova ◽

Françoise de Billy ◽

...

Keyword(s):

Medicago Truncatula ◽

Fluorescent In Situ Hybridization ◽

Fragment Length Polymorphism ◽

Bulked Segregant Analysis ◽

Linkage Groups ◽

Cytogenetic Mapping ◽

Nod Factor ◽

Amplification Fragment Length Polymorphism ◽

Cytogenetic Studies

The DMI1, DMI2, and DMI3 genes of Medicago truncatula, which are required for both nodulation and mycorrhization, control early steps of Nod factor signal transduction. Here, we have used diverse approaches to pave the way for the map-based cloning of these genes. Molecular amplification fragment length polymorphism markers linked to the three genes were identified by bulked segregant analysis. Integration of these markers into the general genetic map of M. truncatula revealed that DMI1, DMI2, and DMI3 are located on linkage groups 2, 5, and 8, respectively. Cytogenetic studies using fluorescent in situ hybridization (FISH) on mitotic and pachytene chromosomes confirmed the location of DMI1, DMI2, and DMI3 on chromosomes 2, 5, and 8. FISH-pachytene studies revealed that the three genes are in euchromatic regions of the genome, with a ratio of genetic to cytogenetic distances between 0.8 and 1.6 cM per μm in the DMI1, DMI2, and DMI3 regions. Through grafting experiments, we showed that the genetic control of the dmi1, dmi2, and dmi3 nodulation phenotypes is determined at the root level. This means that mutants can be transformed by Agrobacterium rhizogenes to accelerate the complementation step of map-based cloning projects for DMI1, DMI2, and DMI3.

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Application of electromagnetic field in anaerobic biodigestion in batch reactors

BioResources ◽

10.15376/biores.15.3.4972-4981 ◽

2020 ◽

Vol 15 (3) ◽

pp. 4972-4981

Author(s):

Julios César de Souza Matos ◽

Ladislav Rozenský ◽

Zdeněk Vrba ◽

Justin Michael Hansen ◽

Miroslav Hájek ◽

...

Keyword(s):

Electromagnetic Field ◽

Anaerobic Digestion ◽

Waste Treatment ◽

Biogas Production ◽

Treatment Plant ◽

Oxygen Demand ◽

Granular Sludge ◽

Anaerobic Treatment ◽

Batch Reactors ◽

Constant Electromagnetic Field

Anaerobic digestion processes with biogas production are widely used for organic waste treatment with an emphasis on energy recovery. Some recent studies have demonstrated the influence of magnetism on microbiological activity. These indicate a possible influence on the efficiency of anaerobic digestion. Thus, technologies that act in anaerobic digestion enhancement can contribute to the improvement of treatment of organic compounds. The present study aimed to verify the influence of a constant electromagnetic field on the anaerobic digestion in anaerobic reactors fed with glucose (2 g/L) at 37 ± 2 °C. In each experiment, reactors were operated with a constant electromagnetic field of 5, 7.5, and 10 mT. The inoculum was granular sludge from an anaerobic treatment plant in a non-selective media culture. Biogas production, chemical oxygen demand (COD), and solids removal were measured during the experiment. Results showed differences in methane production of 21.5% and in COD removal of 15% in the tests with an electromagnetic field of 7.5 mT. These results signs for the viability of the application of a constant magnetic field as a biostimulation agent.

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Start-up of a granular sludge sequencing batch reactor for the treatment of 2,4-dichlorophenol-contaminated wastewater

Water Science & Technology ◽

10.2166/wst.2013.470 ◽

2013 ◽

Vol 68 (10) ◽

pp. 2151-2157 ◽

Cited By ~ 3

Author(s):

S. Milia ◽

R. Porcu ◽

S. Rossetti ◽

A. Carucci

Keyword(s):

Sequencing Batch Reactor ◽

Gradual Increase ◽

Batch Reactor ◽

Scale Up ◽

Granular Sludge ◽

Operating Conditions ◽

Loading Rates ◽

Start Up ◽

Phase Cycle

In this study, a granular sludge sequencing batch reactor (GSBR) was started-up for the biological aerobic treatment of wastewater containing highly toxic 2,4-dichlorophenol (2,4-DCP), in presence of readily biodegradable sodium acetate (NaAc) as the growth substrate. Different influent concentrations of NaAc (420–800 mg/L) and 2,4-DCP (0–20 mg/L), as well as different operating conditions (i.e. cycle length), were tested in order to determine the optimal strategy for successful GSBR start-up: stable granulation and complete 2,4-DCP removal were achieved only when high NaAc influent concentration and volumetric organic loading rates (800 mg/L and 1.9 kgCOD/(m3·d), respectively), prolonged reaction phase (cycle time of 4 hours) and gradual increase of 2,4-DCP concentration in the influent were applied, thus providing useful information for process optimization in view of future scale-up. Granules were initially colonized by fungi which progressively disappeared during the start-up process, and complete 2,4-DCP removal was mostly due to bacterial activity, in particular Betaproteobacteria, as shown by fluorescence in situ hybridization (FISH).

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Effects of the incorporation of drinking water sludge on the anaerobic digestion of domestic wastewater sludge for methane production

Water Science & Technology ◽

10.2166/wst.2015.291 ◽

2015 ◽

Vol 72 (6) ◽

pp. 1016-1021 ◽

Cited By ~ 4

Author(s):

Patricia Torres-Lozada ◽

José Sánchez Díaz-Granados ◽

Brayan Alexis Parra-Orobio

Keyword(s):

Drinking Water ◽

Wastewater Treatment ◽

Anaerobic Digestion ◽

Methane Production ◽

Municipal Wastewater ◽

Treatment Plant ◽

Drinking Water Treatment ◽

Wastewater Sludge ◽

Municipal Wastewater Treatment ◽

Methanogenic Activity

Water purification and wastewater treatment generate sludge, which must be adequately handled to prevent detrimental effects to the environment and public health. In this study, we examined the influence of the application of settled sludge from a drinking water treatment plant (SDWTP) on the anaerobic digestion (AD) of the thickened primary sludge from a municipal wastewater treatment plant (SWWTP) which uses chemically assisted primary treatment (CAPT). On both plants the primary coagulant is ferric chloride. The study was performed at laboratory scale using specific methanogenic activity (SMA) tests, in which mixtures of SWWTP–SDWTP with the ratios 100:00, 80:20, 75:25, 70:30 and 00:100 were evaluated. Methane detection was also performed by gas chromatography for a period of 30 days. Our results show that all evaluated ratios that incorporate SDWTP, produce an inhibitory effect on the production of methane. The reduction in methane production ranged from 26% for the smallest concentration of SDWTP (20%) to more than 70% for concentrations higher than 25%. The results indicated that the hydrolytic stage was significantly affected, with the hydrolysis constant Kh also reduced by approximately 70% (0.24–0.26 day−1 for the different ratios compared with 0.34 day−1 for the SWWTP alone). This finding demonstrates that the best mixtures to be considered for anaerobic co-digestion must contain a fraction of SDWTP below 20%.

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