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Microorganisms May 2024This study extensively analyzed the bacterial information of biofilms and activated sludge in oxic reactors of full-scale moving bed biofilm reactor-integrated...
This study extensively analyzed the bacterial information of biofilms and activated sludge in oxic reactors of full-scale moving bed biofilm reactor-integrated fixed-film activated sludge (MBBR-IFAS) systems. The bacterial communities of biofilms and activated sludge differed statistically (R = 0.624, < 0.01). The denitrifying genera , , , and were more abundant in activated sludge ( < 0.05), while comammox was more abundant in biofilms ( < 0.05), with an average relative abundance of 8.13%. and had weak co-occurrence relationships with other genera in the MBBR-IFAS systems. Potential function analysis revealed no differences in pathways at levels 1 and 2 based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) between biofilms and activated sludge. However, in terms of pathways at level 3, biofilms had more potential in 26 pathways, including various organic biodegradation and membrane and signal transportation pathways. In comparison, activated sludge had more potential in only five pathways, including glycan biosynthesis and metabolism. With respect to nitrogen metabolism, biofilms had greater potential for nitrification (ammonia oxidation) (M00528), and complete nitrification (comammox) (M00804) concretely accounted for methane/ammonia monooxygenase (K10944, K10945, and K10946) and hydroxylamine dehydrogenase (K10535). This study provides a theoretical basis for MBBR-IFAS systems from the perspective of microorganisms.
PubMed: 38930504
DOI: 10.3390/microorganisms12061121 -
Microorganisms May 2024This study used next-generation sequencing to assess the impact of combined capric acid (C10) and lauric acid (C12) on the ruminal bacterial composition. Eight Holstein...
This study used next-generation sequencing to assess the impact of combined capric acid (C10) and lauric acid (C12) on the ruminal bacterial composition. Eight Holstein cows were randomly assigned to two groups using a cross-over design. The cows were fed two silage-based diets with the addition of either 100 g of stearic acid per cow per day (control), or 50 g of capric acid and 50 g of lauric acid per cow per day (C10 + C12). On day 18, 250 mL of rumen fluid was collected from each cow, and DNA was isolated, amplified, and sequenced. Treatment did not alter bacterial diversity indices, the relative abundance of archaea, nor the fiber-degrading microorganisms, except for a decrease in (from 2.9% to 0.7%; = 0.04). The relative abundance of decreased (from 39.9% to 29.6%; = 0.009), which is notable because some members help to efficiently utilize ammonia by releasing it slowly into the rumen. Furthermore, the relative abundance of increased (from 28.4% to 41.5%; = 0.008), which may have aided the increased ammonia-nitrogen levels in the rumen, as this class contains hyperammonia-producing members. Our study reveals alterations in bacterial abundances with implications for rumen ammonia levels, offering insights into potential strategies for modulating rumen fermentation processes and methane production in ruminant livestock.
PubMed: 38930467
DOI: 10.3390/microorganisms12061085 -
Microorganisms May 2024Although root (AMR) has been noted as an ingredient in ruminant feed, the impacts of AMR feeding on rumen fermentation and the microbial community structure within the...
Although root (AMR) has been noted as an ingredient in ruminant feed, the impacts of AMR feeding on rumen fermentation and the microbial community structure within the rumen are yet to be evaluated. This study investigated the effects of AMR supplementation on rumen fermentation characteristics and microbial community structures in goats. In two sets of feeding experiments, four Japanese native goats were fed AMR (10 g/kg DM/day/head) for three weeks per experiment. The rumen fluid samples were analyzed using high-performance liquid chromatography for fermentation products and next-generation sequencing for microbial analysis. The rumen fluid samples in the second experiment were also subject to an in vitro anaerobic fermentation test. The results indicated a significant modification, with a higher volatile fatty acid (VFA) content in the rumen fluid of goats in the feeding period than before feeding ( < 0.01). The microbial analysis revealed a significant increase in community diversity ( < 0.05) following AMR feeding, and the rumen bacterial community increased in two families belonging to the order Oscillospirales in Firmicutes ( < 0.05). The phylum Verrucomicrobiota was observed to be significantly less abundant after AMR feeding than during the control period ( < 0.05). Notably, the linear discriminant analysis revealed that the families with largely unknown functions in the rumen (Oscillospiraceae, Rikenellaceae, Muribaculaceae, and vadinBB97) were the determinants of the community split between control and AMR feeding. Increased fermentation rate by AMR feeding was also supported by an in vitro culture experiment, which resulted in faster VFA production without affecting methane production in total gas production. The study demonstrated that AMR can significantly facilitate change in the bacterial community structure in the goat rumen involving a shift of the favoring fibrolytic bacteria towards VFA production. The long-term effects of AMR supplementation and its applicability across different ruminant species, with potential benefits for animal health and productivity, should be addressed.
PubMed: 38930452
DOI: 10.3390/microorganisms12061067 -
Animals : An Open Access Journal From... Jun 20243-nitropropionic acid (3NPA) has been proposed as an useful modifier to mitigate ruminal enteric methane emissions. However, few studies investigated the effects of 3NPA...
3-nitropropionic acid (3NPA) has been proposed as an useful modifier to mitigate ruminal enteric methane emissions. However, few studies investigated the effects of 3NPA on ruminal fermentation characteristics of grazing ruminants in vitro. Rumen fluid from grazing yak and cattle were collected and incubated with additions of 0, 8, and 16 mM 3NPA. The total gas production, CH production, and dry matter digestibility significantly decreased with increasing 3NPA doses in both ruminant species ( < 0.05) and methane production decreased to almost 100% in cattle at 8 mM NPA but not yak, while H accumulation showed an opposite trend. The total fatty acid (TVFA) production, acetate concentration, and propionate concentration in cattle decreased as 3NPA doses increased at 12 and 24 h incubation. For yak, the H accumulation reached its apex at 8 mM NPA ( < 0.05). The TVFA in yak decreased significantly with increasing 3NPA doses at 12 and 72 h incubation. Moreover, the acetate concentration and propionate concentration in yak decreased as 3NPA doses increased at 12 and 24 h incubation. Overall, these findings demonstrated that 3NPA could be used as a strategy to mitigate methane emissions; although, it negatively affected the dry matter degradability in vitro.
PubMed: 38929423
DOI: 10.3390/ani14121804 -
Animals : An Open Access Journal From... Jun 2024A deeper understanding of gas emissions in milk production is crucial for promoting productive efficiency, sustainable resource use, and animal welfare. This paper aims... (Review)
Review
A deeper understanding of gas emissions in milk production is crucial for promoting productive efficiency, sustainable resource use, and animal welfare. This paper aims to analyze ammonia and greenhouse gas emissions in dairy farming using bibliometric methods. A total of 187 English-language articles with experimental data from the Scopus and Web of Science databases (January 1987 to April 2024) were reviewed. Publications notably increased from 1997, with the highest number of papers published in 2022. Research mainly focuses on ammonia and methane emissions, including quantification, volatilization, and mitigation strategies. Other gases like carbon dioxide, nitrous oxide, and hydrogen sulfide were also studied. Key institutions include the University of California-Davis and Aarhus University. Bibliometric analysis revealed research evolution, identifying trends, gaps, and future research opportunities. This bibliometric analysis offers insights into emissions, air quality, sustainability, and animal welfare in dairy farming, highlighting areas for innovative mitigation strategies to enhance production sustainability. This research contributes to academia, enhancing agricultural practices, and informing environmental policies. It is possible to conclude that this research is a valuable tool for understanding the evolution of research on gas emissions in dairy cattle facilities, providing guidance for future studies and interventions to promote more sustainable production.
PubMed: 38929340
DOI: 10.3390/ani14121721 -
International Journal of Molecular... Jun 2024A family of bifunctional dihetarylmethanes and dibenzoxanthenes is assembled via a reaction of acetals containing a 2-chloroacetamide moiety with phenols and related...
A family of bifunctional dihetarylmethanes and dibenzoxanthenes is assembled via a reaction of acetals containing a 2-chloroacetamide moiety with phenols and related oxygen-containing heterocycles. These compounds demonstrated selective antitumor activity associated with the induction of cell apoptosis and inhibition of the process of glycolysis. In particular, bis(heteroaryl)methane containing two 4-hydroxy-6-methyl-2-pyran-2-one moieties combine excellent in vitro antitumor efficacy with an IC of 1.7 µM in HuTu-80 human duodenal adenocarcinoma models with a high selectivity index of 73. Overall, this work highlights the therapeutic potential of dimeric compounds assembled from functionalized acetals and builds a starting point for the development of a new family of anticancer agents.
Topics: Humans; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Methane; Cell Proliferation; Xanthenes
PubMed: 38928428
DOI: 10.3390/ijms25126724 -
Nature Communications Jun 2024Borgs are huge extrachromosomal elements (ECE) of anaerobic methane-consuming "Candidatus Methanoperedens" archaea. Here, we used nanopore sequencing to validate...
Borgs are huge extrachromosomal elements (ECE) of anaerobic methane-consuming "Candidatus Methanoperedens" archaea. Here, we used nanopore sequencing to validate published complete genomes curated from short reads and to reconstruct new genomes. 13 complete and four near-complete linear genomes share 40 genes that define a largely syntenous genome backbone. We use these conserved genes to identify new Borgs from peatland soil and to delineate Borg phylogeny, revealing two major clades. Remarkably, Borg genes encoding nanowire-like electron-transferring cytochromes and cell surface proteins are more highly expressed than those of host Methanoperedens, indicating that Borgs augment the Methanoperedens activity in situ. We reconstructed the first complete 4.00 Mbp genome for a Methanoperedens that is inferred to be a Borg host and predicted its methylation motifs, which differ from pervasive TC and CC methylation motifs of the Borgs. Thus, methylation may enable Methanoperedens to distinguish their genomes from those of Borgs. Very high Borg to Methanoperedens ratios and structural predictions suggest that Borgs may be capable of encapsulation. The findings clearly define Borgs as a distinct class of ECE with shared genomic signatures, establish their diversification from a common ancestor with genetic inheritance, and raise the possibility of periodic existence outside of host cells.
Topics: Genome, Archaeal; Methane; Phylogeny; Oxidation-Reduction; Archaea; Nanopore Sequencing; DNA Methylation; Soil Microbiology
PubMed: 38926353
DOI: 10.1038/s41467-024-49548-8 -
Nature Communications Jun 2024Tuning the oxygen activity in perovskite oxides (ABO) is promising to surmount the trade-off between activity and selectivity in redox reactions. However, this remains...
Tuning the oxygen activity in perovskite oxides (ABO) is promising to surmount the trade-off between activity and selectivity in redox reactions. However, this remains challenging due to the limited understanding in its activation mechanism. Herein, we propose the discovery that generating subsurface A-site cation (La) vacancy beneath surface Fe-O layer greatly improved the oxygen activity in LaFeO, rendering enhanced methane conversion that is 2.9-fold higher than stoichiometric LaFeO while maintaining high syngas selectivity of 98% in anaerobic oxidation. Experimental and theoretical studies reveal that absence of La-O interaction lowered the electron density over oxygen and improved the oxygen mobility, which reduced the barrier for C-H bond cleavage and promoted the oxidation of C-atom, substantially boosting methane-to-syngas conversion. This discovery highlights the importance of A-site cations in modulating electronic state of oxygen, which is fundamentally different from the traditional scheme that mainly credits the redox activity to B-site cations and can pave a new avenue for designing prospective redox catalysts.
PubMed: 38926349
DOI: 10.1038/s41467-024-49776-y -
Environmental Science and Pollution... Jun 2024The effects of adding vinasse (VIN) as a co-substrate on the stability and production of volatile fatty acids (VFA) and methane (CH) during the anaerobic digestion (AD)...
The effects of adding vinasse (VIN) as a co-substrate on the stability and production of volatile fatty acids (VFA) and methane (CH) during the anaerobic digestion (AD) of microalgal biomass (MB) were evaluated. The AD system consisted of an acidogenic reactor (AR) followed by a methanogenic reactor (MR). The experiment was divided into phase I-start-up and AD of VIN; phase II-MB+VIN co-digestion (50:50 based on chemical oxygen demand (COD)); and phase III-co-digestion of pretreated MB and VIN (PTMB+VIN, 50:50). In phase I, the total amount of VFA in the AR increased from 240 to 2126 mg/L. In the MR, the conversion of VFA into CH yielded an average of 71 ± 37 NmL CH/g COD. In phase II, the initial CH production was 246 ± 31 mL CH/g COD but it decreased to 63 mL CH/g COD due to the accumulation of longer chain acids. More stable conditions were achieved after two hydraulic retention cycles and the average CH yield in this phase was 183 mL CH/g COD. In phase III, when using PTMB, 197 ± 72 NmL CH/g COD were obtained, i.e., a 2.7- and 1.1-fold increases compared to phases I and II, respectively. The predominance of acetate producers and syntrophic organisms suggests acetoclastic methanogenesis, confirmed by the occurrence of Methanosaeta (10.5%).
PubMed: 38926305
DOI: 10.1007/s11356-024-34089-w -
Environmental Research Jun 2024Methane is a short-lived greenhouse gas but has a far greater warming effect than carbon dioxide. At the same time, the livestock sector serves as a large contributor to...
Methane is a short-lived greenhouse gas but has a far greater warming effect than carbon dioxide. At the same time, the livestock sector serves as a large contributor to global emissions of anthropogenic methane. Herein, this work aimed to use cultivated seaweed supplementation to reduce methane emissions and investigate the potential influencing mechanism. To evaluate the feasibility, two cultivated seaweeds, Laminaria japonica Aresch, and Porphyra tenera, along with the enzymatic hydrolysates derived from L. japonica, underwent in vitro trials, and they were both added into corn silage feed (CSF) with different concentrations (1%, 5%, and 10% of CSF) for methane reduction evaluation. The results indicated that >75% and 50% reductions in methane production were observed for the seaweeds and seaweed enzymatic hydrolysates in 9- and 30-day, respectively. Combined high-throughput sequencing and multivariate analysis revealed that supplementation with seaweed and seaweed enzymatic hydrolysates had a notable impact on the prokaryotic community structure. Mantel tests further revealed that significant correlations between the prokaryotic community and methane accumulation (P < 0.05), implying the prokaryotic community plays a role in reducing methane emissions within the rumen. Correspondingly, the networks within the prokaryotic community unveiled the crucial role of propionate/butyrate-producing bacteria in regulating methane emissions through microbial interactions. The predicted function of the prokaryotic community exhibited a significant reduction in the presence of the narB gene in seaweed-supplemented treatments. This reduction may facilitate an increased rate of electron flow toward the nitrate reduction pathway while decreasing the conversion of H to methane. These results indicated the supplementation of cultivated seaweeds and the enzymatic hydrolysates has the potential to reshape the community structure of rumen microbial communities, and this alteration appears to be a key factor contributing to their methane production-reduction capability.
PubMed: 38925466
DOI: 10.1016/j.envres.2024.119458