RESUMO
In this study, the inclusion of water fly (Notonecta sp., NT) meal was compared with conventional protein sources such as soybean meal (SBM) and fish meal (FM) in diets destined for sheep, with specific reference to growth performance, nutrient intake, nitrogen balance, and in vitro rumen fermentation parameters. For 21 days, 18 male Suffolk lambs were randomly assigned to three experimental diets fed: (1) SBM at 130 g/kg dry matter (DM), as a plant-based protein diet; (2) FM at 50 g/kg DM, as an animal-based protein diet; and (3) NT at 60 g/kg DM, as an insect-based protein diet, for ad libitum feed intake. DM intake was similar among the treatments. The digestibility of DM (p = 0.006) and organic matter (p = 0.002) in the NT group was lower than that of SBM. In vitro rumen fermentation data showed that there were no differences between the treatments for DM degradation and the production of microbial crude protein. No differences were observed among the treatments in terms of enteric methane production. The NT diet produced the lowest NH3-N at hours 12 and 24 (p = 0.032 and 0.021, respectively). Overall, the dietary inclusion of NT for fattening lambs could be an alternative feeding strategy without deleterious effects on animal performance.
Assuntos
Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Dieta , Proteínas Alimentares , Fermentação , Nitrogênio , Rúmen , Animais , Ovinos/metabolismo , Nitrogênio/metabolismo , Masculino , Rúmen/metabolismo , Proteínas Alimentares/administração & dosagem , Proteínas Alimentares/metabolismo , Fenômenos Fisiológicos da Nutrição Animal/fisiologia , Dieta/veterinária , Ingestão de Alimentos/fisiologia , Digestão , Dípteros/metabolismo , Dípteros/crescimento & desenvolvimento , Glycine max , Metano/metabolismoRESUMO
CONTEXT OR PROBLEM: Most of the research evaluating rice varieties, a major global staple food, for greenhouse gas (GHG) mitigation has been conducted under continuous flooding. However, intermittent irrigation practices are expanding across the globe to address water shortages, which could alter emissions of methane (CH4) compared to nitrous oxide (N2O) for reducing overall global warming potential (GWP). To develop climate-smart rice production systems, it is critical to identify rice varieties that simultaneously reduce CH4 and N2O emissions while maintaining crop productivity under intermittent irrigation. OBJECTIVE: This study assessed CH4 and N2O emissions, grain yield, and GWP of four rice varieties cultivated under intermittent irrigation in Colombia. METHODS: Four common commercial rice varieties were evaluated over two seasons-wet and dry in 2020 and 2021-in two Colombian regions (Tolima and Casanare). RESULTS: Wet-season crop productivity was similar among varieties. However, F68 in Tolima and F-Itagua in Casanare significantly reduced yields in the dry season, likely due to periods of crop water stress. Overall, CH4 emissions and GWP were relatively low due to frequent field drainage events, with GWP ranging from 349 to 4704 kg CO2 equivalents ha-1. Accordingly, N2O emissions contributed 73% to GWP across locations, as wet-dry cycles can increase N2O emissions, creating a tradeoff for GWP when reducing CH4 through drainage. Varieties F67 in Tolima and F-Itagua in Casanare significantly reduced GWP by 32-61% across seasons, primarily by decreasing N2O rather than CH4 emissions. CONCLUSIONS: Rice varietal selection achieved significant GWP mitigation with limited impacts on grain yield, mainly due to reduced N2O emissions under non-continuously flooded irrigation. IMPLICATIONS/SIGNIFICANCE: This research underscores the critical role of rice varietal selection in addressing global climate-change and water-scarcity challenges, which drive the adoption of intermittent irrigation practices. By focusing on reducing N2O emissions through appropriate variety selection, this study provides valuable insights for rice systems worldwide that are adapting to these pressing environmental challenges.
Assuntos
Irrigação Agrícola , Metano , Óxido Nitroso , Oryza , Metano/metabolismo , Óxido Nitroso/análise , Óxido Nitroso/metabolismo , Oryza/crescimento & desenvolvimento , Aquecimento Global , Gases de Efeito Estufa/análise , ColômbiaRESUMO
Seaweed plays a significant role in reducing green-house gasses (GHG) emitted by ruminant animals, in particular methane gas (CH4) generated during rumen fermentation of the feed. Euchaema cottonii is one of potential cultivated seaweed in tropical country. A preservation procedure is necessary for further application in CH4 reduction program. The study looked at how three drying methods (sun drying, oven drying, and freeze drying) affected the E.cottonii ability in reducing CH4 methane as measured by an in vitro technique. The addition of dried E. cottonii up to 4% dry matter (DM) was tested using rice straw diets mixed with concentrate in the ratio of 70%:30% in DM base. Measurements was conducted on gas production, degradability and end product of rumen fermentation during 48-hour incubation using a gas production system and ANKOM Daisy II techniques. Overall, the three dried products of E. cottonii found to considerably lower production of CH4, increased DM and OM degradability as well as total VFA production (P<0.05). The three treatments have no effect on NH3 concentration and the bacterial population, but decreased protozoa population (P<0.01). The lowering of CH4 gas production in the rumen is impacted by all three drying methods in the same way. It is concluded that dried E.cottonii addition up to 4% DM effective in depressing enteric CH4 production, without causing negative effect on DM and OM degradability as well as did not depress total VFA formation and bacterial activities. The three different drying-methods have similar effect on reducing CH4 production, with the most affective is freeze-drying method.
Assuntos
Fermentação , Metano , Rúmen , Alga Marinha , Animais , Metano/biossíntese , Metano/metabolismo , Rúmen/metabolismo , Rúmen/microbiologia , Alga Marinha/química , Ração Animal , Dessecação/métodos , Algas Comestíveis , RodófitasRESUMO
Biochemical methane potential (BMP) test is an important tool to evaluate the methane production biodegradability and toxicity of different wastes or wastewaters. This is a key parameter for assessing design and feasibility issues in the full-scale implementation of anaerobic digestion processes. A standardized and storable inoculum is the key to obtain reproducible results. In Uruguay, a local enterprise dedicated to design and install anaerobic digesters operated a lab-scale bioreactor as a source of biomass for BMP tests, using a protocol previously described. This reactor was controlled and fed with a mixture of varied organic compounds (lipids, cellulolytic wastes, proteins). Biomass was reintroduced into the reactor after BMP assays to maintain a constant volume and biomass concentration. The aim of this work was to evaluate how the microbial community evolved during this operation and the effect of storing biomass in the refrigerator. The composition of the microbial communities was analyzed by 16S rRNA amplicon sequencing using primers for Bacteria and Archaea. The methanogenic activity was determined, and the methanogens were quantified by mcrA qPCR. One sample was stored for a 5-month period in the refrigerator (4 °C); the activity and the microbial community composition were analyzed before and after storage. Results showed that applying the reported methodology, a reliable methanogenic sludge with an acceptable SMA was obtained even though the reactor suffered biomass alterations along the evaluated period. Refrigerating the acclimatized biomass for 5 months did not affect its activity nor its microbial composition according to the 16S rRNA gene sequence analysis, even though changes in the mcrA abundance were observed. KEY POINTS: ⢠The applied methodology was successful to obtain biomass suitable to perform BMP assays. ⢠The microbial community was resilient to external biomass addition. ⢠Biomass storage at 4 °C for 5 months did not alter the methanogenic activity.
Assuntos
Archaea , Bactérias , Biomassa , Reatores Biológicos , Metano , RNA Ribossômico 16S , Esgotos , Metano/metabolismo , Reatores Biológicos/microbiologia , Bactérias/genética , Bactérias/metabolismo , Bactérias/classificação , Bactérias/isolamento & purificação , Archaea/genética , Archaea/metabolismo , Archaea/classificação , Anaerobiose , RNA Ribossômico 16S/genética , Esgotos/microbiologia , Microbiota , Biodegradação AmbientalRESUMO
Methanogens, which are found exclusively in the Archaea domain of life, have the potential to help solve future energy challenges by producing methane. As a result, their metabolism has attracted significant attention in recent years. Despite being unable to grow on sugars, they store glycogen, which raises intriguing questions about the role of this polymer in methanogen metabolism and the signals that trigger its degradation when methanogenic substrates are not available. Here, we examined genomic databases to identify the enzymes responsible for glycogen synthesis and degradation in methanogens and explored the critical role of glycogen when nutrients and methanogenic substrates are scarce. Additionally, we analyzed the metabolic pathways involved in glycogen metabolism and their connection to the various types of methanogenesis exhibited by these organisms. Potential regulatory steps are proposed based on the reported effectors. Also, by employing the Alphafold3 server, the structural location of these sites in the enzyme structure was predicted, highlighting the advantages and limitations of this tool. Analysis of the allosteric effectors involved in this regulation suggests that energy charge may be the signal that triggers the metabolic switch from gluconeogenesis and glycogen storage to glycolysis and methanogenesis.
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Glicogênio , Metano , Archaea/metabolismo , Archaea/genética , Gluconeogênese , Glicogênio/metabolismo , Glicólise , Redes e Vias Metabólicas , Metano/metabolismo , Nutrientes/metabolismoRESUMO
This study aimed to evaluate the influence of probiotic bacteria (Pediococcus acidilactici BX-B122 and Bacillus coagulans BX-B118) on methane, carbon monoxide, and hydrogen sulfide, and fermentation profile of dietary Delonix regia seeds in ruminant. Ruminal contents from slaughtered rams and steers were used as inoculum for in vitro fermentation system. The total gas, methane, carbon monoxide, and hydrogen sulfide volume, as well as pH and dry matter degradability, were quantified in three fermentation cycles. Probiotic bacteria reduced the production of methane and hydrogen sulfide, while also increasing (P < 0.05) dry matter biodegradability, short-chain fatty acids, and metabolizable energy in both rams and steers. Delonix regia seeds at 6, 12, and 18% reduced total gas production. Higher production of methane and carbon monoxide was observed in rams compared to steers. Interestingly, no impact (P > 0.05) on the pH of the ruminal contents was found in Delonix regia seeds alone or in combination with probiotics. However, higher (P < 0.05) methane conversion efficiency (i.e., ratios of methane: short-chain fatty acids, methane: metabolizable energy, and methane: organic matter) was observed in experimental diets with Delonix regia seeds compared to diets containing both Delonix regia seeds and probiotic bacteria. In conclusion, dietary inclusion of 6, 12, and 18% of Delonix regia seeds with probiotic bacteria (Pediococcus acidilactici BX-B122 and Bacillus coagulans BX-B118) can mitigate the production of methane and hydrogen sulfide, while also increasing dry matter biodegradability, short-chain fatty acids, and metabolizable energy both ruminant animals.
Assuntos
Gases de Efeito Estufa , Metano , Probióticos , Rúmen , Animais , Rúmen/metabolismo , Rúmen/microbiologia , Bovinos , Metano/metabolismo , Fermentação , Sementes , Masculino , Ração Animal , Dieta/veterinária , FabaceaeRESUMO
Tropical estuarine systems play several ecological roles, such as acting as a nursery for biodiversity and cycling nutrients and greenhouse gases. However, the phylogenetic and metabolic diversity of estuarine microbiomes is not completely known. Furthermore, it is unclear how seasonal patterns may affect microbial diversity in these systems. The aim of the present study was to determine the metagenomic diversity and its major drivers in a large tropical estuarine system dominated by a mangrove forest in the South Atlantic around the Paraiba do Sul River. In total, 12.16 million shotgun sequences were generated (dry season: n = 8; wet season: n = 5), and water-quality parameters were evaluated for all locations. Metagenomic sequences were distributed between two patterns: (1) the dry season, in which the families Rhodobactereaceae and Flavobactereaceae increased, and (2) the wet season, in which Moraxellaceae, Pseudomonadaceae, Pseudoalteromonadaceae were more abundant. The dry season was characterized by higher salinity, nitrogen fixation, nitrification, and photosynthetic potential. In contrast, the wet season had higher carbon dioxide (CO2) and methane (CH4) production and a higher abundance of methanogenic, methylotrophic, and chemoorganotrophic bacteria in samples with low salinity. These findings suggest a possible relationship with the production of greenhouse gases during the wet period.
Assuntos
Estuários , Microbiota , Clima Tropical , Monitoramento Ambiental , Bactérias/classificação , Bactérias/genética , Estações do Ano , Microbiologia da Água , Brasil , Biodiversidade , Metano/metabolismoRESUMO
Methanogenic communities of hypersaline microbial mats of Guerrero Negro, Baja California Sur, Mexico, have been recognized to be dominated by methylotrophic methanogens. However, recent studies of environmental samples have evidenced the presence of hydrogenotrophic and methyl-reducing methanogenic members, although at low relative abundances. Physical and geochemical conditions that stimulate the development of these groups in hypersaline environments, remains elusive. Thus, in this study the taxonomic diversity of methanogenic archaea of two sites of Exportadora de Sal S.A was assessed by mcrA gene high throughput sequencing from microcosm experiments with different substrates (both competitive and non-competitive). Results confirmed the dominance of the order Methanosarcinales in all treatments, but an increase in the abundance of Methanomassiliiccocales was also observed, mainly in the treatment without substrate addition. Moreover, incubations supplemented with hydrogen and carbon dioxide, as well as the mixture of hydrogen, carbon dioxide and trimethylamine, managed to stimulate the richness and abundance of other than Methanosarcinales methanogenic archaea. Several OTUs that were not assigned to known methanogens resulted phylogenetically distributed into at least nine orders. Environmental samples revealed a wide diversity of methanogenic archaea of low relative abundance that had not been previously reported for this environment, suggesting that the importance and diversity of methanogens in hypersaline ecosystems may have been overlooked. This work also provided insights into how different taxonomic groups responded to the evaluated incubation conditions.
Assuntos
Metano , Metano/metabolismo , México , Salinidade , Filogenia , Biodiversidade , Hidrogênio/metabolismo , Dióxido de Carbono/metabolismo , Archaea/genética , Archaea/metabolismo , Archaea/classificação , Microbiota , Metilaminas/metabolismoRESUMO
The study evaluated the performance of thermophilic co-digestion in both single-stage methanogenic reactors (TMR) and two-stage systems, consisting of a thermophilic acidogenic reactor and a thermophilic sequential methanogenic reactor (TSMR). A 1:1 mixture of sugarcane vinasse and molasses was codigested in anaerobic fluidized bed reactors, with varying organic matter concentrations based on chemical oxygen demand (COD) ranging from 5 to 22.5 g COD L-1. Both systems achieved high organic matter removal efficiency (51 to 86.5%) and similar methane (CH4) yields (> 148 mL CH4 g-1CODremoved). However, at the highest substrate concentration (22.5 g COD L-1), the TSMR outperformed the TMR in terms of energy generation potential (205.6 kJ d-1 vs. 125 kJ d-1). Phase separation in the two-stage system increased bioenergy generation by up to 43.5% at lower substrate concentrations (7.5 g COD L-1), with hydrogen (H2) generation playing a critical role in this enhancement. Additionally, the two-stage system produced value-added products, including ethanol (2.3 g L-1), volatile organic acids (3.2 g lactate L-1), and H2 (0.6-2.7 L H2 L-1 d-1). Microbial analysis revealed that Thermoanaerobacterium, Caldanaerobius, and Clostridium were dominant at 5 g COD L-1, while Lactobacillus prevailed at concentrations of ≥ 15 g COD L-1. The primary methane producers in the single-stage system were Methanosarcina, Methanoculleus, and Methanobacterium, whereas Methanothermobacter, Bathyarchaeia, and Methanosarcina dominated in the two-stage system.
Assuntos
Reatores Biológicos , Metano , Melaço , Saccharum , Saccharum/química , Metano/metabolismo , Reatores Biológicos/microbiologia , Anaerobiose , Análise da Demanda Biológica de Oxigênio , BiocombustíveisRESUMO
Our aim was to evaluate a whole-grain diet containing 0 (T1) and 60% (T2) waste papaya silage in vitro, in situ and in vivo. In vitro, biogas, methane and dry matter degradation (DMDiv), neutral detergent fiber (NDFDiv) and crude protein (CPDiv) were determined at 72 h; in situ, DM (DMDis), NDF (NDFis) and CP (CPDis) digestibility was determined at 72 h; in vivo, consumption and apparent digestibility of DM (DMI and DMD) and NDF (NDFI and NDFD), daily weight gain (DWG), rumen characteristics (pH, bacterial and protozoan counts) were determined. In addition, we performed coproparasitoscopic analysis and interviews with producers. Biogas production, methane, DMDiv, CDPiv, DMDis, DMD, NDFD, pH, bacterial and protozoan counts, and parasite load of nematodes and coccidia were not different between treatments (p > 0.05). T2 showed more NDFDiv, CPDis, DMI, NDFI, DWG than T1, while T1 was higher than T2 in NDFDis (p < 0.05). The results obtained from in vitro, in situ and in vivo techniques indicate that the diet with 60% waste papaya silage (T2) showed a similar response to the control diet (T1). Therefore, waste papaya silage is a non-conventional feeding alternative for weaned calves in the Costa Chica region of the state of Guerrero, Mexico.
Assuntos
Carica , Dieta , Digestão , Rúmen , Silagem , Aumento de Peso , Animais , Silagem/análise , Carica/química , Bovinos , Rúmen/parasitologia , Rúmen/microbiologia , Rúmen/metabolismo , Dieta/veterinária , Ração Animal/análise , Metano/metabolismo , Metano/análise , Fenômenos Fisiológicos da Nutrição Animal , Masculino , Biocombustíveis/análise , MéxicoRESUMO
Infrared thermography may be an alternative technology for measuring the amount of CH4 produced and has the advantages of low cost, speed and efficiency in obtaining results. The study's objective was to determine if the infrared thermography is adequate for predicting the emission of CH4 in hair sheep and the best time after feeding to carry out the measurement. Twelve Santa Inês lambs (females, non-pregnant, with twelve months old and mean body weight of 39.3 ± 2.1 kg) remained for two days in respirometric chambers, in a semi-closed system, to determine the CH4 production. The animals were divided into two treatments, according to the diet provided. During this period, seven thermographic photographs were taken, at times - 1 h, -0.5 h, 0 h, 0.5 h, 1 h, 2 h, 3 h, 5 h, and 7 h, according to the feeding time, defined as 0 h. CH4 production was measured over 24 h. Thermographic images measured the maximum, minimum, average and point temperatures at the left and right flanks. The temperature difference between the left and right flanks (left minus right) was calculated each time. Pearson correlation coefficients, multiple regression and principal component analysis were carried out in SAS®. The best prediction of emission intensity of CH4 (kg of CH4 per dry matter intake) was obtained at 3 h after feeding: CH4/DMI = 13.9016-0,38673 * DifP2 + 3.39089 * DifMed2 (R² = 0.48), using the difference between left and right flanks for point and average temperature measures. Therefore, infrared thermography can be used as an indicator of CH4 production in hair sheep three hours after feeding.
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Metano , Carneiro Doméstico , Termografia , Animais , Termografia/veterinária , Termografia/métodos , Metano/análise , Metano/metabolismo , Feminino , Carneiro Doméstico/fisiologia , Ração Animal/análise , Dieta/veterinária , Raios Infravermelhos , Ovinos/fisiologiaRESUMO
To assess microbial dynamics during anaerobic digestion (AD) of sewage sludge (SWS) from a municipal Wastewater Treatment Plant (WWTP), a Biochemical Methane Potential (BMP) assay at 37 °C under mono-digestion conditions was conducted. Utilizing the Illumina MiSeq platform, 16S ribosomal RNA (rRNA) gene sequencing unveiled a core bacterial community in the solid material, showcasing notable variations in profiles. The research investigates changes in microbial communities and metabolic pathways to understand their impact on the efficiency of the digestion process. Prior to AD, the relative abundance in SWS was as follows: Proteobacteria > Bacteroidota > Actinobacteriota. Post-AD, the relative abundance shifted to Firmicutes > Synergistota > Proteobacteria, with Sporanaerobacter and Clostridium emerging as dominant genera. Notably, the methanogenic community underwent a metabolic pathway shift from acetoclastic to hydrogenotrophic in the lab-scale reactors. At the genus level, Methanosaeta, Methanolinea, and Methanofastidiosum predominated initially, while post-AD, Methanobacterium, Methanosaeta, and Methanospirillum took precedence. This metabolic transition may be linked to the increased abundance of Firmicutes, particularly Clostridia, which harbor acetate-oxidizing bacteria facilitating the conversion of acetate to hydrogen.
Assuntos
Reatores Biológicos , Metano , RNA Ribossômico 16S , Esgotos , Esgotos/microbiologia , Anaerobiose , Metano/metabolismo , RNA Ribossômico 16S/genética , Reatores Biológicos/microbiologia , Bactérias/classificação , Bactérias/metabolismo , Bactérias/genética , Bactérias/isolamento & purificação , Hidrogênio/metabolismo , Biocombustíveis , Acetatos/metabolismo , MicrobiotaRESUMO
Methane capture via oxidation is considered one of the 'Holy Grails' of catalysis (Tucci and Rosenzweig, 2024). Methane is also a primary greenhouse gas that has to be reduced by 1.2 billion metric tonnes in 10 years to decrease global warming by only 0.23°C (He and Lidstrom, 2024); hence, new technologies are needed to reduce atmospheric methane levels. In Nature, methane is captured aerobically by methanotrophs and anaerobically by anaerobic methanotrophic archaea; however, the anaerobic process dominates. Here, we describe the history and potential of using the two remarkable enzymes that have been cloned with activity for capturing methane: aerobic capture via soluble methane monooxygenase and anaerobic capture via methyl-coenzyme M reductase. We suggest these two enzymes may play a prominent, sustainable role in addressing our current global warming crisis.
Assuntos
Metano , Oxirredutases , Oxigenases , Proteínas Recombinantes , Metano/metabolismo , Oxigenases/genética , Oxigenases/metabolismo , Oxirredutases/genética , Oxirredutases/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Oxirredução , Anaerobiose , Aerobiose , Archaea/enzimologia , Archaea/genética , Archaea/metabolismoRESUMO
The objectives of the present study were to estimate the heritability for daily methane emission (CH4) and residual daily methane emission (CH4res) in Nellore cattle, as well as to perform genome-wide association studies (GWAS) to identify genomic regions and candidate genes influencing the genetic variation of CH4 and CH4res. Methane emission phenotypes of 743 Nellore animals belonging to 3 breeding programs were evaluated. CH4 was measured using the sulfur hexafluoride (SF6) tracer technique (which involves an SF6 permeation tube introduced into the rumen, and an appropriate apparatus on each animal), and CH4res was obtained as the difference between observed CH4 and CH4 adjusted for dry matter intake. A total of 6,252 genotyped individuals were used for genomic analyses. Data were analyzed with a univariate animal model by the single-step GBLUP method using the average information restricted maximum likelihood (AIREML) algorithm. The effects of single nucleotide polymorphisms (SNPs) were obtained using a single-step GWAS approach. Candidate genes were identified based on genomic windows associated with quantitative trait loci (QTLs) related to the 2 traits. Annotation of QTLs and identification of candidate genes were based on the initial and final coordinates of each genomic window considering the bovine genome ARS-UCD1.2 assembly. Heritability estimates were of moderate to high magnitude, being 0.42â ±â 0.09 for CH4 and 0.21â ±â 0.09 for CH4res, indicating that these traits will respond rapidly to genetic selection. GWAS revealed 11 and 15 SNPs that were significantly associated (Pâ <â 10-6) with genetic variation of CH4 and CH4res, respectively. QTLs associated with feed efficiency, residual feed intake, body weight, and height overlapped with significant markers for the traits evaluated. Ten candidate genes were present in the regions of significant SNPs; 3 were associated with CH4 and 7 with CH4res. The identified genes are related to different functions such as modulation of the rumen microbiota, fatty acid production, and lipid metabolism. CH4 and CH4res presented sufficient genetic variation and may respond rapidly to selection. Therefore, these traits can be included in animal breeding programs aimed at reducing enteric methane emissions across generations.
Genetic selection designed to reduce the amount of enteric methane emission from livestock is a mitigation strategy to ensure more sustainable production over generations since genetic gains are cumulative. Brazil is a large producer of beef, and the Nellore breed (Bos taurus indicus) plays a very important role in this production. There are a few studies evaluating genetic and genomic aspects of enteric methane emission in Nellore cattle. The objectives of the present study were to estimate the heritability of daily methane emission (CH4) and residual daily methane emission (CH4res) in Nellore cattle, as well as to identify genomic regions and candidate genes associated with genetic variation of these traits. The heritability estimates for CH4 and CH4res were of moderate to high magnitude (0.42â ±â 0.09 and 0.21â ±â 0.09, respectively). Genome-wide association analyses revealed new loci associated with methane emission in Nellore cattle on chromosomes 5, 11, 17, and 20, where 10 candidate genes were identified, 3 for CH4 and 7 for CH4res. The 2 traits possess sufficient genetic variability to be included as selection criteria in breeding programs.
Assuntos
Estudo de Associação Genômica Ampla , Metano , Polimorfismo de Nucleotídeo Único , Animais , Bovinos/genética , Metano/metabolismo , Estudo de Associação Genômica Ampla/veterinária , Locos de Características Quantitativas , Masculino , Feminino , Genótipo , Cruzamento , FenótipoRESUMO
Turkey litter waste is lignocellulosic and keratinous, requiring prior enzymatic treatment to facilitate fiber hydrolysis and utilization by microorganisms in anaerobic digestion (AD) process. The understanding of the performance of microorganisms in AD can be facilitated through molecular biology and bioinformatics tools. This study aimed to determine the taxonomic profile and functional prediction of microbial communities in the AD of turkey litter waste subjected to enzymatic pretreatment and correlate it with operational parameters. The tests involved the use of turkey litter (T) at 25 g L-1 of volatile solids, a granular inoculum (S) (10% m/v), and the addition of cellulase (C), and pectinase (P) enzymes at four concentrations. The use of enzymes increased methane production by 19% (turkey litter, inoculum, and cellulase-TSC4) and 15% (turkey litter, inoculum, and enzymatic pectinase-TSP4) compared to the control (turkey litter and inoculum-TS), being more effective in TSC4 (667.52 mLCH4), where there was consumption of acetic, butyric, and propionic acids. The pectinase assay (TSP4) showed a methane production of 648 mLCH4 and there was the accumulation of metabolites. Cellulolytic microorganisms Bacteroides, Ruminofilibacter, Lachnospiraceae, Ruminococcaceae, and Methanosaeta were favored in TSC4. In TSP4, the predominant genus was Macellibacteroides and Methanosarcina, and genes involved in methylotrophic methanogenesis were also found (mtaB, mtmB, and mtbB). Enzymes involved in hydrogenotrophic methanogenesis were identified in both assays (TSC4 and TSP4). Molecular tools helped to understand the metabolic routes involved in AD with enzymatic treatment, allowing the elaboration of strategies to improve the sustainable degradation of turkey litter waste.
Assuntos
Bactérias , Celulase , Metano , Poligalacturonase , Perus , Anaerobiose , Animais , Metano/metabolismo , Celulase/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Bactérias/isolamento & purificação , Perus/microbiologia , Poligalacturonase/metabolismo , Hidrólise , Lignina/metabolismo , Agricultura , MetagenômicaRESUMO
BACKGROUND: Mangroves are complex and dynamic coastal ecosystems under frequent fluctuations in physicochemical conditions related to the tidal regime. The frequent variation in organic matter concentration, nutrients, and oxygen availability, among other factors, drives the microbial community composition, favoring syntrophic populations harboring a rich and diverse, stress-driven metabolism. Mangroves are known for their carbon sequestration capability, and their complex and integrated metabolic activity is essential to global biogeochemical cycling. Here, we present a metabolic reconstruction based on the genomic functional capability and flux profile between sympatric MAGs co-assembled from a tropical restored mangrove. RESULTS: Eleven MAGs were assigned to six Bacteria phyla, all distantly related to the available reference genomes. The metabolic reconstruction showed several potential coupling points and shortcuts between complementary routes and predicted syntrophic interactions. Two metabolic scenarios were drawn: a heterotrophic scenario with plenty of carbon sources and an autotrophic scenario with limited carbon sources or under inhibitory conditions. The sulfur cycle was dominant over methane and the major pathways identified were acetate oxidation coupled to sulfate reduction, heterotrophic acetogenesis coupled to carbohydrate catabolism, ethanol production and carbon fixation. Interestingly, several gene sets and metabolic routes similar to those described for wastewater and organic effluent treatment processes were identified. CONCLUSION: The mangrove microbial community metabolic reconstruction reflected the flexibility required to survive in fluctuating environments as the microhabitats created by the tidal regime in mangrove sediments. The metabolic components related to wastewater and organic effluent treatment processes identified strongly suggest that mangrove microbial communities could represent a resourceful microbial model for biotechnological applications that occur naturally in the environment.
Assuntos
Bactérias , Microbiota , Áreas Alagadas , Microbiota/genética , Bactérias/genética , Bactérias/classificação , Bactérias/metabolismo , Bactérias/isolamento & purificação , Filogenia , Processos Heterotróficos , Ciclo do Carbono , Carbono/metabolismo , Metano/metabolismo , Processos Autotróficos , Redes e Vias Metabólicas/genéticaRESUMO
OBJECTIVES: This lab-scale study aimed to investigate the effect of total ammonia nitrogen (TAN) stress on the methanogenic activity and the taxonomic and functional profiles of the microbial community of anaerobic sludge (AS) from a full-scale bioreactor. METHODS: The AS was subjected to a stepwise increase in TAN every 14 days at concentrations of 1, 2, 2.5, 3, 3.5, and 4 g TAN/L (Acclimated-AS or AAS). This acclimation stage was followed by an ammonia stress stage (4 g/L). A blank-AS (BAS) was maintained without TAN during the acclimation stage. In the second stress stage (ST), the BAS was divided into two new treatments: a control (BAS') and one that received a shock load of TAN of 4 g/L (SBAS'). Methane production was measured, and a metagenomic analysis was conducted to describe the microbial community. RESULTS: A decrease in the relative abundance of Methanothrix soehngenii of 16 % was related to a decrease of 23 % in the methanogenic capacity of AAS when comparing with the final stage of BAS. However, recovery was observed at 3.5 g TAN/L, and a shift to methylotrophic metabolism occurred, indicated by a 4-fold increase in abundance of Methanosarcina mazei. The functional analysis of sludge metagenomes indicated that no statistical differences (p > 0.05, RM ANOVA) were found in the relative abundance of methanogenic genes that initiate acetoclastic and hydrogenotrophic pathways (acetyl-CoA synthetase, ACSS; acetate kinase, ackA; phosphate acetyltransferase, pta; and formylmethanofuran dehydrogenase subunit A, fwdA) into the BAS and AAS during the acclimation phase. The same was observed between groups of genes associated with methanogenesis from methylated compounds. In contrast, statistical differences (p < 0.05, one-way ANOVA) in the relative abundance of these genes were recorded during ST. The functional profiles of the genes involved in acetoclastic, hydrogenotrophic, and methylotrophic methanogenic pathways were brought to light for acclimatation and stress experimental stages. CONCLUSIONS: TAN inhibited methanogenic activity and acetoclastic metabolism. The gradual acclimatization to TAN leads to metabolic and taxonomic changes that allow for the subsequent recovery of methanogenic functionality. The study highlights the importance of adequate management of anaerobic bioprocesses with high nitrogen loads to maintain the methanogenic functionality of the microbial community.
Assuntos
Amônia , Reatores Biológicos , Metano , Esgotos , Metano/metabolismo , Amônia/metabolismo , Anaerobiose , Reatores Biológicos/microbiologia , Esgotos/microbiologia , Nitrogênio/metabolismoRESUMO
Complex cross-talk occurs between gastrointestinal nematodes and gut symbiotic microbiota, with consequences for animal metabolism. To investigate the connection between methane production and endoparasites, this study evaluated the effect of mixed infection with Haemonchus contortus and Trichostrongylus colubriformis on methanogenic and methanotrophic community in rumen microbiota of lambs using shotgun metagenomic and real-time quantitative PCR (qPCR). The rumen content was collected from six Santa Inês lambs, (7 months old) before and after 42 days infection by esophageal tube. The metagenomic analysis showed that the infection affected the microbial community structure leading to decreased abundance of methanotrophs bacteria, i.e. α-proteobacteria and ß-proteobacteria, anaerobic methanotrophic archaea (ANME), protozoa, sulfate-reducing bacteria, syntrophic bacteria with methanogens, geobacter, and genes related to pyruvate, fatty acid, nitrogen, and sulfur metabolisms, ribulose monophosphate cycle, and Entner-Doudoroff Pathway. Additionally, the abundance of methanogenic archaea and the mcrA gene did not change. The co-occurrence networks enabled us to identify the interactions between each taxon in microbial communities and to determine the reshaping of rumen microbiome associations by gastrointestinal nematode infection. Besides, the correlation between ANMEs was lower in the animal's postinfection. Our findings suggest that gastrointestinal parasites potentially lead to decreased methanotrophic metabolism-related microorganisms and genes.
Assuntos
Microbioma Gastrointestinal , Metano , Rúmen , Doenças dos Ovinos , Animais , Rúmen/microbiologia , Rúmen/parasitologia , Ovinos/microbiologia , Metano/metabolismo , Doenças dos Ovinos/microbiologia , Doenças dos Ovinos/parasitologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Archaea/genética , Archaea/classificação , Haemonchus/genética , Trichostrongylus , Microbiota , Infecções por Nematoides/microbiologia , Infecções por Nematoides/veterináriaRESUMO
The ubiquitous use of volatile siloxanes in a myriad of product formulations has led to a widespread distribution of these persistent contaminants in both natural ecosystems and wastewater treatment plants. Microbial degradation under microaerobic conditions is a promising approach to mitigate D4 and D5 siloxanes while recovering energy in wastewater treatment plants. This study examined D4/D5 siloxanes biodegradation under both anaerobic and microaerobic conditions ( [Formula: see text] = 0, 1, 3 %) using wastewater sludge. Results show that the use of microaeration in an otherwise strictly anaerobic environment significantly enhances siloxane conversion to methane. 16S rRNA gene sequencing identified potential degraders, including Clostridium lituseburense, Clostridium bifermentans and Synergistales species. Furthermore, chemical analysis suggested a stepwise siloxane conversion preceding methanogenesis under microaerobic conditions. This study demonstrates the feasibility of microaerobic siloxane biodegradation, laying groundwork for scalable removal technologies in wastewater treatment plants, ultimately highlighting the importance of using bio-based approaches in tackling persistent pollutants.
Assuntos
Biodegradação Ambiental , Metano , Siloxanas , Siloxanas/metabolismo , Metano/metabolismo , Esgotos/microbiologia , RNA Ribossômico 16S/genética , Aerobiose , Águas Residuárias/química , VolatilizaçãoRESUMO
The establishment of sulfate (SO42-) reduction during methanogenesis may considerably hinder the efficient energetic exploitation of methane, once removing sulfide from biogas is obligate and can be costly. In addition, sulfide generation can negatively impact the performance of methanogens by triggering substrate competition and sulfide inhibition. This study investigated the impacts of removing SO42- during fermentation on the performance of a second-stage methanogenic continuous reactor (R2), comparing the results with those obtained in a single-stage system (R1) fed with SO42--rich wastewater (SO42- of up to 400 mg L-1, COD/SO42- of 3.12-12.50). The organic load (OL) was progressively increased to 5.0 g COD d-1 in both reactors, showing completely discrepant performances. Sulfate-reducing bacteria outperformed methanogens in the consumption for organic matter during the start-up phase (OL = 2.5 g COD d-1) in R1, directing up to 73% of the electron flow to SO42- reduction. An efficient methanogenic activity was established in R1 only after decreasing the OL to 0.625 g COD d-1, after which methanogenesis prevailed by consuming ca. 90% of the removed COD. Nevertheless, high sulfide proportions (up to 3.1%) were measured in biogas. Conversely, methanogenesis was promptly established in R2, resulting in a methane-rich (> 80%) and sulfide-free biogas regardless of the operating condition. From an economic perspective, processing the biogas evolved from R2 would be cheaper, although the techno-economic impacts of managing the sulfur pollution in the fermentative reactor still need to be understood.