RESUMEN
Sewage sludge in cities of Yangzi River Belt, China, generally exhibits a lower organic content and higher silt contentdue to leakage of drainage system, which caused low bioenergy recovery and carbon emission benefits in conventional anaerobic digestion (CAD). Therefore, this paper is on a pilot scale, a bio-thermophilic pretreatment anaerobic digestion (BTPAD) for low organic sludge (volatile solids (VS) of 4%) was operated with a long-term continuous flow of 200 days. The VS degradation rate and CH4 yield of BTPAD increased by 19.93% and 53.33%, respectively, compared to those of CAD. The analysis of organic compositions in sludge revealed that BTPAD mainly improved the hydrolysis of proteins in sludge. Further analysis of microbial community proportions by high-throughput sequencing revealed that the short-term bio-thermophilic pretreatment was enriched in Clostridiales, Coprothermobacter and Gelria, was capable of hydrolyzing acidified proteins, and provided more volatile fatty acid (VFA) for the subsequent reaction. Biome combined with fluorescence quantitative polymerase chain reaction (PCR) analysis showed that the number of bacteria with high methanogenic capacity in BTPAD was much higher than that in CAD during the medium temperature digestion stage, indicating that short-term bio-thermophilic pretreatment could provide better methanogenic conditions for BTPAD. Furthermore, the greenhouse gas emission footprint analysis showed that short-term bio-thermophilic pretreatment could reduce the carbon emission of sludge anaerobic digestion system by 19.18%.
Asunto(s)
Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Aguas del Alcantarillado/microbiología , Anaerobiosis , Eliminación de Residuos Líquidos/métodos , Proyectos Piloto , Reactores Biológicos/microbiología , Metano/metabolismo , Metano/análisis , Carbono/metabolismo , Carbono/análisis , China , BiocombustiblesRESUMEN
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
The study of microbial hydrocarbons removal is of great importance for the development of future bioremediation strategies. In this study, we evaluated the removal of a gaseous mixture containing toluene, m-xylene, ethylbenzene, cyclohexane, butane, pentane, hexane and heptane in aerated stirred bioreactors inoculated with Rhodococcus erythropolis and operated under non-sterile conditions. For the real-time measurement of hydrocarbons, a novel systematic approach was implemented using Selected-Ion Flow Tube Mass Spectrometry (SIFT-MS). The effect of the carbon source (â¼9.5 ppmv) on (i) the bioreactors' performance (BR1: dosed with only cyclohexane as a single hydrocarbon versus BR2: dosed with a mixture of the 8 hydrocarbons) and (ii) the evolution of microbial communities over time were investigated. The results showed that cyclohexane reached a maximum removal efficiency (RE) of 53% ± 4% in BR1. In BR2, almost complete removal of toluene, m-xylene and ethylbenzene, being the most water-soluble and easy-to-degrade carbon sources, was observed. REs below 32% were obtained for the remaining compounds. By exposing the microbial consortium to only the five most recalcitrant hydrocarbons, REs between 45% ± 5% and 98% ± 1% were reached. In addition, we observed that airborne microorganisms populated the bioreactors and that the type of carbon source influenced the microbial communities developed. The abundance of species belonging to the genus Rhodococcus was below 10% in all bioreactors at the end of the experiments. This work provides fundamental insights to understand the complex behavior of gaseous hydrocarbon mixtures in bioreactors, along with a systematic approach for the development of SIFT-MS methods.
Asunto(s)
Biodegradación Ambiental , Reactores Biológicos , Hidrocarburos , Rhodococcus , Rhodococcus/metabolismo , Reactores Biológicos/microbiología , Hidrocarburos/metabolismo , Carbono/metabolismo , Contaminantes Atmosféricos/metabolismo , Contaminantes Atmosféricos/análisis , Espectrometría de Masas , Tolueno/metabolismo , Xilenos/metabolismo , Butanos/metabolismo , Derivados del Benceno , PentanosRESUMEN
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.
Asunto(s)
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.
Asunto(s)
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
BACKGROUND: Microbial anaerobic metabolism is a key driver of biogeochemical cycles, influencing ecosystem function and health of both natural and engineered environments. However, the temporal dynamics of the intricate interactions between microorganisms and the organic metabolites are still poorly understood. Leveraging metagenomic and metabolomic approaches, we unveiled the principles governing microbial metabolism during a 96-day anaerobic bioreactor experiment. RESULTS: During the turnover and assembly of metabolites, homogeneous selection was predominant, peaking at 84.05% on day 12. Consistent dynamic coordination between microbes and metabolites was observed regarding their composition and assembly processes. Our findings suggested that microbes drove deterministic metabolite turnover, leading to consistent molecular conversions across parallel reactors. Moreover, due to the more favorable thermodynamics of N-containing organic biotransformations, microbes preferentially carried out sequential degradations from N-containing to S-containing compounds. Similarly, the metabolic strategy of C18 lipid-like molecules could switch from synthesis to degradation due to nutrient exhaustion and thermodynamical disadvantage. This indicated that community biotransformation thermodynamics emerged as a key regulator of both catabolic and synthetic metabolisms, shaping metabolic strategy shifts at the community level. Furthermore, the co-occurrence network of microbes-metabolites was structured around microbial metabolic functions centered on methanogenesis, with CH4 as a network hub, connecting with 62.15% of total nodes as 1st and 2nd neighbors. Microbes aggregate molecules with different molecular traits and are modularized depending on their metabolic abilities. They established increasingly positive relationships with high-molecular-weight molecules, facilitating resource acquisition and energy utilization. This metabolic complementarity and substance exchange further underscored the cooperative nature of microbial interactions. CONCLUSIONS: All results revealed three key rules governing microbial anaerobic degradation. These rules indicate that microbes adapt to environmental conditions according to their community-level metabolic trade-offs and synergistic metabolic functions, further driving the deterministic dynamics of molecular composition. This research offers valuable insights for enhancing the prediction and regulation of microbial activities and carbon flow in anaerobic environments. Video Abstract.
Asunto(s)
Biodegradación Ambiental , Reactores Biológicos , Metabolómica , Microbiota , Anaerobiosis , Reactores Biológicos/microbiología , Bacterias/metabolismo , Bacterias/genética , Bacterias/clasificación , Metagenómica , Metano/metabolismo , Termodinámica , MultiómicaRESUMEN
Two strains of Yarrowia lipolytica (CBS 2075 and DSM 8218) were first studied in bioreactor batch cultures, under different controlled dissolved oxygen concentrations (DOC), to assess their ability to assimilate aliphatic hydrocarbons (HC) as a carbon source in a mixture containing 2 g·L-1 of each alkane (dodecane and hexadecane), and 2 g·L-1 hexadecene. Both strains grew in the HC mixture without a lag phase, and for both strains, 30 % DOC was sufficient to reach the maximum values of biomass and lipids. To enhance lipid-rich biomass and enzyme production, a pulse fed-batch strategy was tested, for the first time, with the addition of one or three pulses of concentrated HC medium. The addition of three pulses of the HC mixture (total of 24 g·L-1 HC) did not hinder cell proliferation, and high protease (> 3000 U·L-1) and lipids concentrations of 3.4 g·L-1 and 4.3 g·L-1 were achieved in Y. lipolytica CBS 2075 and DSM 8218 cultures, respectively. Lipids from the CBS 2075 strain are rich in C16:0 and C18:1, resembling the composition of palm oil, considered suitable for the biodiesel industry. Lipids from the DSM 8218 strain were predominantly composed of C16:0 and C16:1, the latter being a valuable monounsaturated fatty acid used in the pharmaceutical industry. Y. lipolytica cells exhibited high intrinsic surface hydrophobicity (> 69 %), which increased in the presence of HC. A reduction in surface tension was observed in both Y. lipolytica cultures, suggesting the production of extracellular biosurfactants, even at low amounts. This study marks a significant advancement in the valorization of HC for producing high-value products by exploring the hydrophobic compounds metabolism of Y. lipolytica.
Asunto(s)
Alcanos , Alquenos , Técnicas de Cultivo Celular por Lotes , Biomasa , Reactores Biológicos , Medios de Cultivo , Yarrowia , Yarrowia/crecimiento & desarrollo , Yarrowia/metabolismo , Alcanos/metabolismo , Reactores Biológicos/microbiología , Medios de Cultivo/química , Alquenos/metabolismo , Ácidos Grasos/metabolismo , Ácidos Grasos/análisis , Lípidos/biosíntesis , Lípidos/análisis , Oxígeno/metabolismo , Metabolismo de los LípidosRESUMEN
Feedstock variability represents a challenge in lignocellulosic biorefineries, as it can influence both lignocellulose deconstruction and microbial conversion processes for biofuels and biochemicals production. The impact of feedstock variability on microbial performance remains underexplored, and predictive tools for microbial behaviour are needed to mitigate risks in biorefinery scale-up. Here, twelve batches of corn stover were deconstructed via deacetylation, mechanical refining, and enzymatic hydrolysis to generate lignin-rich and sugar streams. These batches and their derived streams were characterised to identify their chemical components, and the streams were used as substrates for producing muconate and butyrate by engineered Pseudomonas putida and wildtype Clostridium tyrobutyricum, respectively. Bacterial performance (growth, product titers, yields, and productivities) differed among the batches, but no strong correlations were identified between feedstock composition and performance. To provide metabolic insights into the origin of these differences, we evaluated the effect of twenty-three isolated chemical components on these microbes, including three components in relevant bioprocess settings in bioreactors, and we found that growth-inhibitory concentrations were outside the ranges observed in the streams. Overall, this study generates a foundational dataset on P. putida and C. tyrobutyricum performance to enable future predictive models and underscores their resilience in effectively converting fluctuating lignocellulose-derived streams into bioproducts.
Asunto(s)
Clostridium tyrobutyricum , Lignina , Ingeniería Metabólica , Pseudomonas putida , Zea mays , Pseudomonas putida/genética , Pseudomonas putida/metabolismo , Lignina/metabolismo , Zea mays/microbiología , Clostridium tyrobutyricum/metabolismo , Clostridium tyrobutyricum/genética , Biotransformación , Reactores Biológicos/microbiología , Azúcares/metabolismo , Butiratos/metabolismoRESUMEN
The advancement of fungal biocontrol agents depends on replacing cereal grains with low-cost agro-industrial byproducts for their economical mass production and development of stable formulations. We propose an innovative approach to develop a rice flour-based formulation of the beneficial biocontrol agent Trichoderma asperelloides CMAA1584 designed to simulate a micro-bioreactor within the concept of full biorefinery process, affording in situ conidiation, extended shelf-life, and effective control of Sclerotinia sclerotiorum, a devastating pathogen of several dicot agricultural crops worldwide. Rice flour is an inexpensive and underexplored byproduct derived from broken rice after milling, capable of sustaining high yields of conidial production through our optimized fermentation-formulation route. Conidial yield was mainly influenced by nitrogen content (0.1% w/w) added to the rice meal coupled with the fermentor type. Hydrolyzed yeast was the best nitrogen source yielding 2.6 × 109 colony-forming units (CFU)/g within 14 days. Subsequently, GControl, GLecithin, GBreak-Thru, GBentonite, and GOrganic compost+Break-Thru formulations were obtained by extrusion followed by air-drying and further assessed for their potential to induce secondary sporulation in situ, storage stability, and efficacy against Sclerotinia. GControl, GBreak-Thru, GBentonite, and GOrganic compost+Break-Thru stood out with the highest number of CFU after sporulation upon re-hydration on water-agar medium. Shelf-life of formulations GControl and GBentonite remained consistent for > 3 months at ambient temperature, while in GBentonite and GOrganic compost+Break-Thru formulations remained viable for 24 months during refrigerated storage. Formulations exhibited similar efficacy in suppressing the myceliogenic germination of Sclerotinia irrespective of their concentration tested (5 × 104 to 5 × 106 CFU/g of soil), resulting in 79.2 to 93.7% relative inhibition. Noteworthily, all 24-month-old formulations kept under cold storage successfully suppressed sclerotia. This work provides an environmentally friendly bioprocess method using rice flour as the main feedstock to develop waste-free granular formulations of Trichoderma conidia that are effective in suppressing Sclerotinia while also improving biopesticide shelf-life. KEY POINTS: ⢠Innovative "bioreactor-in-a-granule" system for T. asperelloides is devised. ⢠Dry granules of aerial conidia remain highly viable for 24 months at 4 °C. ⢠Effective control of white-mold sclerotia via soil application of Trichoderma-based granules.
Asunto(s)
Ascomicetos , Reactores Biológicos , Fermentación , Oryza , Esporas Fúngicas , Reactores Biológicos/microbiología , Ascomicetos/crecimiento & desarrollo , Ascomicetos/metabolismo , Oryza/microbiología , Esporas Fúngicas/crecimiento & desarrollo , Nitrógeno/metabolismo , Hypocreales/metabolismo , Hypocreales/crecimiento & desarrollo , Agentes de Control Biológico/química , Trichoderma/metabolismo , Trichoderma/crecimiento & desarrollo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & controlRESUMEN
High-solid digestion (HSD) for biogas production is a resource-efficient and sustainable method to treat organic wastes with high total solids content and obtain renewable energy and an organic fertiliser, using a lower dilution rate than in the more common wet digestion process. This study examined the effect of reactor type on the performance of an HSD process, comparing plug-flow (PFR) type reactors developed for continuous HSD processes, and completely stirred-tank reactors (CSTRs) commonly used for wet digestion. The HSD process was operated in thermophilic conditions (52 °C), with a mixture of household waste, garden waste and agricultural residues (total solids content 27-28 %). The PFRs showed slightly better performance, with higher specific methane production and nitrogen mineralisation than the CSTRs, while the reduction of volatile solids was the same in both reactor types. Results from 16S rRNA gene sequencing showed a significant difference in the microbial population, potentially related to large differences in stirring speed between the reactor types (1 rpm in PFRs and 70-150 rpm in CSTRs, respectively). The bacterial community was dominated by the genus Defluviitoga in the PFRs and order MBA03 in the CSTRs. For the archaeal community, there was a predominance of the genus Methanoculleus in the PFRs, and of the genera Methanosarcina and Methanothermobacter in the CSTRs. Despite these shifts in microbiology, the results showed that stable digestion of substrates with high total solids content can be achieved in both reactor types, indicating flexibility in the choice of technique for HSD processes.
Asunto(s)
Reactores Biológicos , Reactores Biológicos/microbiología , Eliminación de Residuos/métodos , Residuos Sólidos/análisis , Biocombustibles/análisis , Metano/análisis , Metano/metabolismo , ARN Ribosómico 16S , Bacterias/metabolismo , Bacterias/genética , Archaea/metabolismo , Archaea/genéticaRESUMEN
Microbial Fuel Cells (MFCs) are a sophisticated and advanced system that uses exoelectrogenic microorganisms to generate bioenergy. Predicting performance outcomes under experimental settings is challenging due to the intricate interactions that occur in mixed-species bioelectrochemical reactors like MFCs. One of the key factors that limit the MFC's performance is the presence of a microbial consortium. Traditionally, multiple microbial consortia are implemented in MFCs to determine the best consortium. This approach is laborious, inefficient, and wasteful of time and resources. The increase in the availability of soft computational techniques has allowed for the development of alternative strategies like artificial intelligence (AI) despite the fact that a direct correlation between microbial strain, microbial consortium, and MFC performance has yet to be established. In this work, a novel generic AI model based on subspace k-Nearest Neighbour (SS-kNN) is developed to identify and forecast the best microbial consortium from the constituent microbes. The SS-kNN model is trained with thirty-five different microbial consortia sharing different effluent properties. Chemical oxygen demand (COD) reduction, voltage generation, exopolysaccharide (EPS) production, and standard deviation (SD) of voltage generation are used as input features to train the SS-kNN model. The proposed SS-kNN model offers an accuracy of 100% during training period and 85.71% when it is tested with the data obtained from existing literature. The implementation of selected consortium (as predicted by SS-kNN model) improves the COD reduction capability of MFC by 15.67% than that of its constituent microbes which is experimentally verified. In addition, to prevent the effects of climate change and mitigate water pollution, the implementation of MFC technology ensures clean and green electricity. Consequently, achieving sustainable development goals (SDG) 6, 7, and 13.
Asunto(s)
Fuentes de Energía Bioeléctrica , Consorcios Microbianos , Inteligencia Artificial , Análisis de la Demanda Biológica de Oxígeno , Reactores Biológicos/microbiologíaRESUMEN
Microalgae-based wastewater treatment is a promising technology efficient for nutrient recycling and biomass production. Studies continuously optimize processes to reduce costs and increase productivity. However, changes in the operational conditions affect not only biomass productivity but the dynamics of the overall microbial community. This study characterizes a microalgae culture from an 80 m2 pilot-scale raceway reactor fed with untreated urban wastewater. Operational conditions such as pH, dissolved oxygen control strategies (On-off, PI, Event-based, no control), and culture height were varied to assess microbial population changes. Results demonstrate that increased culture height significantly promotes higher microalgal and bacterial diversity. pH, dissolved oxygen and culture height highly affects nitrifying bacteria activity and nitrogen accumulation. Furthermore, the system exhibited high disinfection capability with average Logarithmic Reduction Values (LRV) of 3.36 for E. coli and 2.57 for Clostridium perfringens. Finally, the fungi species detected included Chytridiomycota and Ascomycota, while purple photosynthetic bacteria were also found in significant abundance within the medium.
Asunto(s)
Microalgas , Aguas Residuales , Aguas Residuales/microbiología , Microalgas/crecimiento & desarrollo , Biomasa , Eliminación de Residuos Líquidos/métodos , Nitrógeno/metabolismo , Reactores Biológicos/microbiología , Bacterias/metabolismoRESUMEN
Temperature is the critical factor affecting the efficiency and cost of anaerobic digestion (AD). The current work develops a shift-temperature AD (STAD) between 35 °C and 55 °C, intending to optimise microbial community and promote substrate conversion. The experimental results showed that severe inhibition of biogas production occurred when the temperature was firstly increased stepwise from 35 °C to 50 °C, whereas no inhibition was observed at the second warming cycle. When the organic load rate was increased to 6.37 g VS/L/d, the biogas yield of the STAD reached about 400 mL/g VS, nearly double that of the constant-temperature AD (CTAD). STAD promoted the proliferation of Methanosarcina (up to 57.32 %), while severely suppressed hydrogenophilic methanogens. However, when the temperature was shifted to 35 °C, most suppressed species recovered quickly and the excess propionic acid was quickly consumed. Metagenomic analysis showed that STAD also promoted gene enrichment related to pathways metabolism, membrane functions, and methyl-based methanogenesis.
Asunto(s)
Biocombustibles , Temperatura , Anaerobiosis , Biocombustibles/microbiología , Reactores Biológicos/microbiología , Metano/metabolismo , Methanosarcina/metabolismo , Microbiota/fisiologíaRESUMEN
Simultaneous nitrification-denitrification (SND) is a promising nitrogen removal process. However, total nitrogen (TN) removal is limited due to unsatisfactory denitrification. This study demonstrated that short-time (1 h) pre-anoxic electro-stimulation significantly enhanced SND efficiency in the aerobic phase by promoting the proliferation of mixotrophic and heterotrophic denitrifiers. SND and TN removal efficiencies at the optimal electric current (EC) (0.02 A) were 85.6 % and 93.9 %, which were 39.1 % and 17.2 % higher than control. Microbial community analysis indicated that the abundance of mixotrophic and heterotrophic denitrifiers significantly increased. H2 generated in the electro-stimulation process induced the proliferation of mixotrophic denitrifiers. The weak EC (0.02 A) promoted the activity and growth of heterotrophic denitrifiers by accelerating electron transfer. They concurrently mediated heterotrophic denitrification to enhance SND efficiency. PICRUSt2 analysis revealed that the abundance of denitrifying genes dramatically surged. This study provides new insights into applying electrolysis to achieve advanced SND while minimizing electricity consumption.
Asunto(s)
Biopelículas , Reactores Biológicos , Desnitrificación , Electrólisis , Nitrificación , Nitrógeno , Reactores Biológicos/microbiología , Nitrógeno/metabolismo , Electricidad , Bacterias/metabolismoRESUMEN
Global urbanization requires more stable and sustainable wastewater treatment to reduce the burden on the water environment. To address the problem of substrate inhibition of microorganisms during wastewater treatment, which leads to unstable wastewater discharge, this study proposes an approach to enhance the tolerance of bacterial community by artificially setting up a non-lethal high substrate environment. And the feasibility of this approach was explored by taking the inhibition of anammox process by nitrite as an example. It was shown that the non-lethal high substrate environment could enhance the nitrite tolerance of anammox bacterial community, as the specific anammox activity increasing up to 24.71 times at high nitrite concentrations. Moreover, the system composed of anammox bacterial community with high nitrite tolerance also showed greater resistance (two-fold) in response to nitrite shock. The antifragility of the system was enhanced without affecting the operation of the main reactor, and the non-lethal high nitrite environment changed the dominant anammox genera to Candidatus Jettenia. This approach to enhance tolerance of bacterial community in a non-lethal high substrate environment not only allows the anammox system to operate stably, but also promises to be a potential strategy for achieving stable biological wastewater treatment processes to comply with standards.
Asunto(s)
Bacterias , Reactores Biológicos , Nitritos , Aguas Residuales , Purificación del Agua , Aguas Residuales/microbiología , Aguas Residuales/química , Nitritos/metabolismo , Bacterias/metabolismo , Bacterias/efectos de los fármacos , Bacterias/genética , Purificación del Agua/métodos , Reactores Biológicos/microbiología , Eliminación de Residuos Líquidos/métodos , Oxidación-ReducciónRESUMEN
Species composition of the healthy adult gut microbiota tends to be stable over time. Destabilization of the gut microbiome under the influence of different factors is the main driver of the microbial dysbiosis and subsequent impacts on host physiology. Here, we used metagenomics data from a Swedish longitudinal cohort, to determine the stability of the gut microbiome and uncovered two distinct microbial species groups; persistent colonizing species (PCS) and transient colonizing species (TCS). We validated the continuation of this grouping, generating gut metagenomics data for additional time points from the same Swedish cohort. We evaluated the existence of PCS/TCS across different geographical regions and observed they are globally conserved features. To characterize PCS/TCS phenotypes, we performed bioreactor fermentation with faecal samples and metabolic modeling. Finally, using chronic disease gut metagenome and other multi-omics data, we identified roles of TCS in microbial dysbiosis and link with abnormal changes to host physiology.
Asunto(s)
Bacterias , Disbiosis , Heces , Microbioma Gastrointestinal , Metagenómica , Disbiosis/microbiología , Humanos , Metagenómica/métodos , Suecia , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Heces/microbiología , Estudios Longitudinales , Metagenoma , Adulto , Reactores Biológicos/microbiología , FermentaciónRESUMEN
Istamycins (ISMs) are 2-deoxyfortamine-containing aminoglycoside antibiotics (AGAs) produced by Streptomyces tenjimariensis ATCC 31603 with broad-spectrum bactericidal activities against most of the clinically relevant pathogens. Therefore, this study aimed to statistically optimize the environmental conditions affecting ISMs production using the central composite design (CCD). Both the effect of culture media composition and incubation time and agitation rate were studied as one factor at the time (OFAT). The results showed that both the aminoglycoside production medium and the protoplast regeneration medium gave the highest specific productivity. Results also showed that 6 days incubation time and 200 rpm agitation were optimum for their production. A CCD quadratic model of 17 runs was employed to test three key variables: initial pH, incubation temperature, and concentration of calcium carbonate. A significant statistical model was obtained including, an initial pH of 6.38, incubation temperature of 30 ËC, and 5.3% CaCO3 concentration. This model was verified experimentally in the lab and resulted in a 31-fold increase as compared to the unoptimized conditions and a threefold increase to that generated by using the optimized culture media. To our knowledge, this is the first report about studying environmental conditions affecting ISM production as OFAT and through CCD design of the response surface methodology (RSM) employed for statistical optimization. In conclusion, the CCD design is an effective tool for optimizing ISMs at the shake flask level. However, the optimized conditions generated using the CCD model in this study should be scaled up in a fermenter for industrial production of ISMs by S. tenjimariensis ATCC 31603 considering the studied environmental conditions that significantly influence the production proces.
Asunto(s)
Antibacterianos , Medios de Cultivo , Fermentación , Streptomyces , Temperatura , Streptomyces/metabolismo , Streptomyces/crecimiento & desarrollo , Medios de Cultivo/química , Concentración de Iones de Hidrógeno , Antibacterianos/biosíntesis , Antibacterianos/farmacología , Carbonato de Calcio/metabolismo , Aminoglicósidos/farmacología , Microbiología Industrial , Reactores Biológicos/microbiologíaRESUMEN
The study of human intestinal physiology and host-microbe interactions is crucial for understanding gastrointestinal health and disease. Traditional two-dimensional cell culture models lack the complexity of the native intestinal environment, limiting their utility in studying intestinal biology. Here, we present a detailed protocol for the set up and utilization of a three-dimensional (3D) in vitro bioreactor system for human intestinal studies and bacterial co-culture. This article outlines the design and assembly of the bioreactor system, scaffold fabrication, bacterial culture techniques, analysis methods, and troubleshooting tips. By providing step-by-step instructions, the goal is to enable other laboratories to utilize physiologically relevant tissue models of the human intestine, incorporating key features, such as nutrient flow, multiple human cell types, 3D architecture, and microbial communities. The incorporation of commensal bacteria into the bioreactor system allows for the investigation of complex host-microbe interactions, providing insight into gastrointestinal health and pathology. This article serves as a comprehensive resource for scientists seeking to advance their understanding of intestinal biology toward the development of novel therapeutic strategies for gastrointestinal disorders. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Scaffold design Basic Protocol 2: Intestinal cell culture: Caco2 cells Basic Protocol 3: Intestinal cell culture: organoids Basic Protocol 4: Bioreactor design and set up Basic Protocol 5: Bacteria in 3D bioreactor set up Basic Protocol 6: Bacteria and drug dosing.
Asunto(s)
Reactores Biológicos , Técnicas de Cocultivo , Intestinos , Humanos , Reactores Biológicos/microbiología , Técnicas de Cocultivo/métodos , Técnicas de Cocultivo/instrumentación , Intestinos/microbiología , Intestinos/citología , Células CACO-2 , Microbioma Gastrointestinal , Técnicas de Cultivo Tridimensional de Células/métodos , Técnicas de Cultivo Tridimensional de Células/instrumentaciónRESUMEN
The anammox reaction simultaneously utilizes ammonia and nitrite as substrates; however, high nitrite concentrations act as strong inhibitors of the reaction. In this study, inhibition by NO2- and free nitrous acid (FNA) was separately evaluated in continuous feeding tests using different biomass carriers. The influent NO2- concentration was increased under pH 7.6, where FNA is less likely to affect anammox activity. A continuous test using polyethylene glycol (PEG) gel carriers containing immobilized anammox bacteria showed that the inhibition ratio was 13% when the NO2--N concentration in the reactor was 350 mg L-1 (FNA ≤0.06 mg L-1). The relationship between NO2- concentration in the reactor and inhibition ratio increased linearly. Evaluation of the inhibitory effect of FNA by increasing the influent NO2- concentration at pH 6.4, where FNA is easily formed, demonstrated that the relationship between FNA and inhibition ratio could be fitted to a sigmoid curve, and the 50% inhibitory concentration (IC50) of FNA was 0.88 mg L-1. A similar test performed using polyvinyl alcohol carriers containing anammox bacteria on their surface showed the same trend as the PEG gel carriers, with the IC50 for FNA at 0.70 mg L-1. These results indicate that the inhibitory effect of FNA on anammox activity was greater than that of NO2-. The evaluation of these two factors helped identify important operational indicators of the stable application of anammox processes.
Asunto(s)
Amoníaco , Reactores Biológicos , Nitritos , Ácido Nitroso , Nitritos/metabolismo , Nitritos/química , Ácido Nitroso/metabolismo , Reactores Biológicos/microbiología , Amoníaco/metabolismo , Oxidación-Reducción , Polietilenglicoles/química , Polietilenglicoles/farmacología , Bacterias/metabolismo , Bacterias/efectos de los fármacos , Concentración de Iones de Hidrógeno , BiomasaRESUMEN
In recirculating aquaculture systems (RAS), maintaining water quality in aquaculture tanks is a paramount factor for effective fish production. A down-flow hanging sponge (DHS) reactor, a trickling filter system used for water treatment of RAS that employs sponges to retain biomass, has high nitrification activity. However, nitrification in seawater RAS requires a long start-up time owing to the high salinity stress. Therefore, this study aimed to evaluate the nitrification characteristics and changes in the microbial community during the conversion of freshwater to seawater in a DHSreactor fed with ammonia-based artificial seawater. The total ammonia nitrogen concentration reached 1.0â¯mg-N·L-1 (initial concentration 10â¯mg-N·L-1) within 11 days of operation, and nitrate production was observed. The 16â¯S rRNA gene sequence of the DHS-retained sludge indicated that the detection rate of the ammonia-oxidizing archaeon Candidatus Nitrosocosmicus decreased from 23.9â¯% to 14.0â¯% and 25.8-17.6â¯% in the upper and lower parts of the DHS reactor, respectively, after the introduction of seawater. In contrast, the nitrite-oxidizing bacteria Nitrospira spp. increased from 0.1â¯% to 9.5â¯% and from 0.5â¯% to 10.5â¯%, respectively. The ammonia oxidation rates of 0.12 ± 0.064 and 0.051 ± 0.0043â¯mg-N·g-MLVSS-1·h-1 on the 37th day in the upper and bottom layers, respectively. Thus, nitrification in the DHS reactor performed well, even under high-salinity conditions with short operational days. This finding makes the transition from freshwater to saltwater fish in the RAS system simple and economical, and has the potential for early start-up of the RAS.