Search Results (1,311)

To explore a new approach to reducing the use of external carbon sources and phosphorus removal chemicals in conventional wastewater treatment, this study developed an anaerobic–oxic–anoxic sequencing batch reactor (AOA-SBR) system (Rf) with iron shavings addition (180 g, 60 g/L), using a blank reactor (R0) as the control. Synthetic wastewater with a C/N ratio of 7.5 was used as the influent. The operating cycle of the AOA-SBR reactor consisted of a 120 min anaerobic phase, a 120 min aerobic phase, and a 60 min anoxic phase, with a hydraulic retention time (HRT) of 12 h. Results showed that the SVI₃₀ of Rf remained at approximately 35 mL/g. The average removal efficiencies of TN and TP in Rf reached 70% and 96%, respectively, which were higher than those of the control. The addition of waste iron shavings improved sludge settleability and nitrogen and phosphorus removal performance of the biochemical system. Fe-C microelectrolysis significantly enriched Candidatus_Competibacter and Candidatus_Nitrocosmicus while inhibiting nitrite-oxidizing bacteria (NOB). This triggered persistent low-level nitrite accumulation within the system, diversified nitrogen-removal pathways, and ultimately improved the total nitrogen-removal efficiency. The extended anaerobic period in the anaerobic–oxic–anoxic (AOA) mode enriched phosphate-accumulating organisms, achieving synergistic chemical and biological phosphorus removal. This study provides a novel strategy for advanced wastewater treatment without external carbon sources or phosphorus additives. Full article

Background: Artemisia absinthium (A. absinthium) is a perennial plant valued for its antibacterial, antioxidant, and anti-inflammatory properties, exhibiting broader therapeutic potential. Given the need to deliver low doses of A. absinthium extract, mesoporous silica nanoparticles have attracted considerable attention as promising nanocarriers due to their distinctive physical and chemical properties. Methods: Physicochemical characterization of the materials was performed and biological assays were conducted to investigate the ROS, antibacterial and antioxidant activity of A. absinthium extract encapsulated within cerium- and calcium-doped mesoporous silica nanoparticles (MNSiCaCe) against both aerobic and anaerobic bacteria. Results: FTIR, SEM, and BET analysis confirmed successful synthesis of the MNSiCaCe. Phytochemical profiling of Artemisia absinthium extract using HPLC revealed the presence of artemisinin and a rich composition of phenolic and flavonoid constituents, with a total phenolic content of 182 ± 3.6 mg GAE/100 g dry plant material and a total flavonoid content of 42.5 ± 0.6 mg QE/100 g. Quantitative drug loading profiling demonstrated that while plain MNSi nanocarriers achieved a loading capacity of 16.96%, the MNSiCaCe enhanced this threshold to 43.11%. The in vitro controlled-release kinetics exhibited a highly prolonged and slow-release profile of the MNSiCaCe. The materials demonstrated excellent hemocompatibility and high mitochondrial activity with human periodontal ligament cells (hPDLCs). Elevated ROS generation was observed under conditions where antibacterial activity was most pronounced. While the artemisinin-doped nanoparticles showed notable antibacterial effects, the complete Artemisia absinthium-loaded nanoparticles achieved a significantly greater reduction in bacterial viability probably due to the synergistic interaction between artemisinin and the extract’s rich polyphenol profile. Conclusions: These findings highlight MNSiCaCe as a promising and safe nanocarrier system for drug delivery, with strong antibacterial potential, offering valuable applications in antibacterial therapies. Full article

Packing density regulates the microenvironment of tobacco (Nicotiana tabacum L.) fermentation and may thereby influence microbial activity and product quality. However, its effects on microbial community assembly and quality formation remain poorly understood. This study aimed to clarify how packing density affects flue-cured tobacco quality by shaping microbial communities, functional potential, and ecological interactions. Here, we investigated the effects of three packing densities (60%, 70%, and 80%) on chemical components, aroma compounds, microbial community structure, functional potential, co-occurrence networks, and assembly mechanisms of flue-cured tobacco (cv. Piaohe No. 2) after 10 days of fermentation. Moderate density (70%) achieved the most balanced chemical profile, with appropriate nicotine retention, potassium/chlorine ratio, and sugar/nicotine balance. T70 also exhibited the highest levels of total esters, total ketones, and β-ionone, key contributors to fruity, floral, and woody aromas. Microbial analysis revealed that T70 supported the highest diversity and was characterized by the enrichment of aroma-related bacterial taxa, including Bacillus and lactic acid bacteria, as well as the fungal genus Pichia. In contrast, T60 favored aerobic nicotine degraders, whereas T80 selected for obligate anaerobes associated with off-odor production. Functional predictions and network analysis showed that T70 upregulated fatty acid and carotenoid biosynthesis pathways and exhibited the highest modularity, indicating a compartmentalized, functionally complementary community. Neutral model fitting revealed increasing stochasticity with density, with T70 displaying a mixed assembly regime. Collectively, our findings show that packing density influences tobacco quality by regulating microbial community composition, functional potential, network interactions, and assembly processes. These results provide a scientific basis for optimizing packing density in tobacco processing. Full article

Endodontic–periodontal lesions are complex conditions in which endodontic infection and periodontal breakdown coexist and may create anaerobic microbial niches along the root surface. Although smoking is a well-established modifier of periodontal disease progression and subgingival microbial ecology, its influence on the depth-related distribution of anaerobic periodontal bacteria in teeth affected by endodontic–periodontal lesions remains incompletely understood. This cross-sectional study investigated the distribution patterns and co-occurrence of selected anaerobic periodontal bacteria in smokers and non-smokers with endodontic–periodontal lesions, considering periodontal pocket depth and anatomical site. Subgingival samples were collected from periodontal pockets of different probing depths (3–4 mm, 5–6 mm, and ≥7 mm), as well as from healthy gingival sulci and oral mucosa, in 26 patients with endodontic–periodontal lesions. The presence of Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Prevotella nigrescens, and Aggregatibacter actinomycetemcomitans was assessed. Detection was performed using polymerase chain reaction (PCR). Qualitative detection frequencies and microbial co-occurrence patterns were compared between smokers and non-smokers across sites and pocket depths. Non-smokers showed higher detection of Tannerella forsythia in pockets ≥ 7 mm (p < 0.05). Overall microbial co-occurrence was lower in smokers in deeper periodontal pockets, whereas detection patterns in healthy gingival sulci and oral mucosa were broadly comparable between groups. Our findings suggest that smoking may be associated with an attenuated depth-related detection pattern and reduced co-occurrence of selected anaerobic periodontal bacteria in endodontic–periodontal lesions. Full article

Biogenically recovered mixed metal(loid) sulfides (BPS) obtained from metallurgical effluents were evaluated as sustainable photocatalysts for the solar-driven degradation of Rhodamine B (RhB). The material, recovered using biogenic sulfide produced by sulfate-reducing bacteria in an upflow anaerobic sludge bed reactor, was mainly composed of Sb₂S₃ and Bi-containing sulfide phases and exhibited a fibrous morphology and a narrow direct band gap of 1.306 eV. Under solar irradiation, BPS achieved RhB degradation efficiencies above 98% under the evaluated conditions (0.8 g L⁻¹ catalyst and 5 mg L⁻¹ dye), consistently outperforming reagent-grade Sb₂S₃. Photocatalytic degradation followed pseudo-first-order kinetics (R² > 0.90), and the apparent reaction rate constant was more than five times higher than that of the reference material under the best-performing conditions. A preliminary reusability assessment and post-reaction characterization after three photocatalytic cycles revealed no significant morphological or compositional changes in BPS. These results demonstrate that waste-derived metal(loid) sulfides recovered through a biogenic process can serve as effective solar photocatalysts, highlighting a promising circular-economy strategy for transforming metallurgical residues into value-added materials for water remediation. Full article

Glycine betaine transport systems are widely exploited by bacteria to survive osmotic stress and represent potential entry routes for antimicrobial delivery. Here, we investigate the bactericidal glycine betaine analog Tox-GB and its uptake, intracellular fate, and antimicrobial activity in Escherichia coli K-12 under osmotic stress. We show that the xenobiotic enters cells via a hierarchical uptake route involving the osmotically regulated compatible solute transporters ProU and ProP, ABC- and MFS-type transporters, respectively. ProU functions as the primary high-affinity transporter at low concentrations, whereas ProP provides a secondary uptake route at somewhat higher substrate levels. Loss of either transporter confers partial resistance, while simultaneous inactivation of both systems causes full resistance, underscoring their functional redundancy and the robustness of Tox-GB import. Intracellularly, Tox-GB undergoes oxygen-dependent degradation, yielding 4-nitrobenzaldehyde and dimethylglycine. While 4-nitrobenzaldehyde contributes to toxicity under aerobic conditions, Tox-GB remains bactericidal under anaerobic conditions, indicating additional oxygen-independent mechanisms involving either the parent compound or unidentified metabolites. These findings suggest a complex intracellular fate and multifactorial mode of action. Despite initial promise as a Trojan horse antimicrobial strategy, the use of Tox-GB for practical applications faces key limitations. Resistance readily emerges via transporter inactivation, and intrinsic resistance occurs in species lacking appropriate compatible solute uptake systems. Structural constraints in glycine betaine transporters further restrict design flexibility. Osmotic regulation limits activity to specific niches, and potential host toxicity stemming from reactive metabolites raises safety concerns. Collectively, these findings highlight the mechanistic complexity and translational challenges faced by glycine betaine–derived xenobiotics as antimicrobial agents. Full article

Background/Objectives: Oral and maxillofacial infections present polybacterial profiles, including both aerobic and anaerobic bacteria. Increasing antibiotic resistance poses a significant challenge to pharmacological treatment of these infections. The aim of this study was to present a bacterial profile and assess antibiotic resistance found in these infections. Methods: This retrospective analysis is based on medical records of 224 patients affected with maxillofacial infections. Microbiological cultures and antibiotic susceptibility testing were performed for all patients. Results: In 78.57% of the patients, a positive microbiological culture was obtained. A total of 72.72% of culture-positive patients showed multi-bacterial cultures (128/176). Predominant bacteria included Streptococcus, detected in 156 cases (39%), followed by Staphylococcus, found in 64 cases (16%), and Prevotella, detected in 56 of 400 total bacterial isolates (14%). The most often isolated aerobic strains were Streptococcus mitis/oralis detected in 64 (16%) cases and Staphylococcus epidermidis detected in 48 cases (12%), while the most common anaerobic strains were Prevotella buccae detected in 14 cases (3.5%). Streptococcus and Staphylococcus exhibited the greatest resistance to clindamycin, accounting for 51.74% and 47.63%, respectively. Aerobic Gram-positive cocci were more resistant to penicillin and amoxicillin than to cephalosporins. Among obligate anaerobes, the lowest antibiotic resistance seen was to metronidazole. The obligate anaerobes except Prevotella were sensitive to clindamycin. Conclusions: A high rate of clindamycin resistance among aerobic and facultatively anaerobic Gram-positive cocci indicates the need to reassess the use of clindamycin in empirical therapy. The bacterial composition of infections suggests the need to use combined antibiotic therapy. First- and second-generation cephalosporins may be an effective alternative to penicillin and its derivatives. Full article

Background: Cervical cancer is primarily caused by the human papillomavirus (HPV), with persistent infections progressing to low- (LGSIL) and high-grade (HGSIL) lesions. Emerging evidence indicates that the cervicovaginal microbiota influences HPV persistence and disease progression, although the underlying metabolic mechanisms remain unclear. Therefore, we assessed the relationship between the cervicovaginal microbiota and the metabolic milieu in women with cervical dysplasia and HPV infections. Methods: We recruited 36 non-menopausal, non-pregnant women who were classified as negative, LGSIL, or HGSIL based on pathology and HPV results. Cervical swabs were collected for genomic DNA extraction to characterize bacterial communities using 16S rRNA sequencing and to perform HPV genotyping. Cervical lavages were collected for untargeted metabolomic profiling using Gas Chromatography-Mass Spectrometry. Integrative multiomic analysis was performed using the MIMOSA2 pipeline. Results: Although bacterial community structure was not different between groups, women with HGSIL had higher richness and exhibited a higher abundance of Prevotella bivia, Prevotella buccalis, and Lachnospiraceae G-9 oral taxon 924. Lesion-positive samples had shifts in tyramine and putrescine, biogenic amines linked to cancer development. Specifically, Pseudomonas was identified as a potential contributor to tyramine oxidation. Conclusions: Cervical lesions and HPV risk are associated with shifts in the cervicovaginal microbial metabolic milieu, highlighting the role of low-abundant anaerobic bacteria. Despite the small sample size, biogenic amines were associated with anaerobic taxa and microbial dysbiosis. These findings warrant further assessment of microbial-derived metabolites and their potential to promote tumor progression by driving a pro-inflammatory, metabolically altered microenvironment. Full article

The accumulation of intermediate products, particularly volatile fatty acids (VFAs) like propionic acid (HPr) or its dissociated form, can inhibit biogas production during anaerobic digestion (AD) at low concentrations. Knowledge about the response of microorganisms to VFA inhibition can help control the digesters. In this study, we aimed to determine how sodium propionate (NaPr) inhibits the AD of municipal sewage sludge by identifying shifts in the microbial community. Four 5 L reactors were operated in semi-continuous mode using sewage sludge and then loaded with different levels of NaPr. The reactors operated at 37 °C with two hydraulic retention times. The results show that there was no apparent inhibition of biogas production at NaPr loading up to 20.3 mmol·L⁻¹. However, moderate inhibition was observed at 81 mmol·L⁻¹, corresponding to an approximate 10% decrease in methane production, while a ≈40% decrease in methane production was observed at 135.3 mmol·L⁻¹. Sequencing analysis revealed that the community composition was dominated by Bacillota, Bacteroidota, Proteobacteria, Chloroflexi, and Cloacimonadota, with Halobacterota and Euryarchaeota as the main archaeal groups. PERMANOVA revealed incubation time as the primary driver of community structure, followed by NaPr concentration. Elevated NaPr levels resulted in a decline in Methanothrix and Methanobrevibacter and promoted distinct syntrophic propionate-oxidizing bacteria (SPOB). Full article

Traditional fermented dairy products represent an important source of autochthonous microorganisms with potential applications in food biotechnology. This study aimed to isolate and characterize microorganisms from the traditional Kazakh fermented product kurt collected from different regions of the Abai area (Kazakhstan) and to evaluate their suitability for biotechnological applications in meat processing. Microbial isolation was performed using MRS medium under anaerobic conditions, followed by morphological and physiological characterization. Accurate identification was carried out using MALDI-TOF MS and 16S rRNA gene sequencing. The results showed that microbial counts ranged from 10⁶ to 10⁸ CFU/g, confirming high microbial diversity of kurt. MALDI-TOF MS analysis revealed the presence of Pichia fermentans, Enterococcus faecalis, Leuconostoc mesenteroides, and Lactobacillus helveticus, indicating that MRS medium supports the growth of both lactic acid bacteria and accompanying microbiota. Subsequent molecular analysis confirmed Leuconostoc mesenteroides and Lactobacillus helveticus as the most promising strains. These isolates demonstrated tolerance to salt, acidic conditions, and mesophilic temperatures, which are essential for meat fermentation processes. In contrast, Enterococcus faecalis was excluded from further application due to potential safety concerns. Overall, the study demonstrates that kurt is a valuable source of technologically important microorganisms and that the identified strains (Leuconostoc mesenteroides and Lactobacillus helveticus) are promising candidates for the development of starter cultures for fermented goat meat processing. Full article

It is crucial to consider newer antibiotics with activity against anaerobes and Helicobacter pylori, given their healthcare importance, and the constantly growing antibiotic resistance/multidrug resistance, which complicates the therapy. The aim of this review was to emphasize certain recently approved or still-under-investigation antibiotics with potential benefits for treating Clostridioides difficile infections (CDIs), other anaerobic infections, and those caused by H. pylori, covering recent data from articles published primarily in 2020–2026. Given the limited number of antibiotics for treating CDI and fidaxomicin nonavailability in many countries, it is necessary to conduct more extensive laboratory and clinical studies of promising antibiotics such as ibezapolstat, delafloxacin, lascufloxacin, omadacycline, eravacycline, ridinilazole, and CRS3123. Against Bacteroides fragilis group species, delafloxacin and eravacycline showed good activity. Research on rifasutenizol for bacterial vaginosis, sarecycline and nadifloxacin for acne vulgaris and amixicile for periodontal diseases needs to be expanded. For H. pylori infection, delafloxacin, sitafloxacin, nemonoxacin, zoliflodacin, and rifasutenizol may improve the suboptimal success of most eradication regimens. However, more efforts, in coordination between medical, scientific, manufacturing, and government representatives, should ensure wider access to and research on the newer antibacterials. Establishing more research groups, careful examination of market issues, and additional approaches, such as nanomaterials, efflux pump inhibitors, phage therapy, and CRISPR-Cas systems, should be beneficial. Notwithstanding the difficulties, there are many opportunities to promote research on and potential use of newer antibiotics which show advantages over the older antibacterials, and to make them available to numerous countries and patients worldwide. Full article

Anaerobic digesters (ADs) are widely used for the recovery of energy from biomass waste, while performance deterioration of ADs sometimes occurs under high organic loads. Microbial electrolysis cells (MECs) have been examined for incorporation into ADs to improve methane production, while responses of MEC-assisted ADs (MEC-ADs) to changes in operational conditions have yet to be sufficiently examined. Here we operated laboratory ADs and MEC-ADs with food waste as a feed, and organic loading rates (OLRs) were varied by changing hydraulic residence times (HRTs). Analyses of AD performances, including methane production and chemical oxygen demand (COD) removal, show that MEC-ADs exhibit higher performances than ADs at OLRs of 7 g COD L⁻¹ D⁻¹ or higher (HRT of 10 days or less). In addition, pH was stably maintained in MEC-ADs at high OLRs. Metabarcoding of rRNA gene amplicons showed that Desulfuromonadaceae bacteria were enriched at the anodes in MEC-ADs, while Methanobacteriaceae archaea were increased at the cathodes. It is suggested that the MEC system is useful for stably operating ADs at high OLRs and/or short HRTs. Full article

To screen high-quality porcine-derived lactic acid bacteria for swine production, this study compared growth performance, acid production, acid and bile salt tolerance, and genome characteristics of Lactobacillus plantarum (MRS002), Lactobacillus amylovorus (MRS003), and Lactobacillus salivarius (MRS004). All experiments were performed with three biological replicates, and data were analyzed using the GraphPad Prism software 8.4.3 by one-way analysis of variance (one-way ANOVA) followed by Tukey’s multiple comparison test (significance level p < 0.05). All three strains showed typical anaerobic growth. L. amylovorus MRS003 had a longer growth cycle and higher biomass, while L. plantarum MRS002 and L. salivarius MRS004 grew faster and produced more acid, with pH values reaching 4.2 and 4.3 at 24 h, respectively. L. plantarum MRS002 and L. salivarius MRS004 also exhibited higher survival rates under 0.3% bile salt and pH 2.0 stress. Genome annotation revealed that more than 50% of genes were related to metabolism in all strains. L. plantarum MRS002 possessed the most comprehensive metabolic and stress-resistance gene networks; L. amylovorus MRS003 shows genomic enrichment in starch-degradation pathways and appears promising for high-starch feed fermentation; and L. salivarius MRS004 showed unique advantages in aromatic amino acid metabolism (e.g., phenylalanine, tyrosine, and tryptophan biosynthesis). In summary, based on the evaluated in vitro indicators, L. salivarius MRS004 has more favorable phenotypic characteristics, L. plantarum MRS002 has broad adaptability, and L. amylovorus MRS003 is suitable for high-starch feed fermentation. This study provides a theoretical basis for the research and development of probiotic products. Full article

Greenhouse gas generated from wastewater treatment plants has attracted much attention as it has the potential to be recovered and used as an energy source. In this study, a membrane biofilm reactor was designed to simultaneously enhance nitrate removal and reduce methane (CH₄) emissions during methane oxidation coupled with the denitrification process. The enrichment of CH₄-driven denitrification microbes with a relatively short hydraulic retention time (HRT) and its effects on the stable operation of the reactor were studied within 250 d. With an increasing HRT from 8 to 20 h, a removal rate of up to approximately 0.51 mg/L·h⁻¹ was achieved, which also kept the effluent NO₂⁻-N below 0.5 mg/L. Microbial community analysis showed that the diversity and uniformity of microorganism communities decreased with the addition of CH₄ as a carbon source, and the microbial structure changed significantly. Compared with that of seed sludge at the phylum level, the relative abundance of Proteobacteria increased significantly, Alphaproteobacteria and Sphingobacteriia continued to become enriched, and the abundance of Methylocystis increased significantly. Neither denitrifying anaerobic methane oxidation (DAMO) archaea nor bacteria were found in the sequencing analysis. Methylocystis was the dominant CH₄ oxidizing bacteria, in synergy with the co-occurrence of autotrophic and heterotrophic denitrifying bacteria, which likely join up in nitrogen removal. Unlike the systems described in most methane-driven denitrification studies, our system achieved nitrate removal without detectable DAMO microbes. Full article

Background: The role of bacterial infection in canine extrahepatic biliary disease remains inconsistently characterized. This retrospective case series evaluated associations between ultrasonographic gallbladder findings and bile culture results in dogs. Materials and Methods: Sixty-seven dogs were screened between March 2024 and December 2025, of which 49 met inclusion criteria (clinical, biochemical, and ultrasonographic evidence of gallbladder disease) and underwent bile sampling by ultrasound-guided cholecystocentesis (n = 45) or intraoperative collection (n = 4). Samples were cultured aerobically and anaerobically; isolates identified by MALDI-TOF MS were further tested for in vitro antimicrobial susceptibility using Kirby–Bauer disk diffusion method. Results: Among the 49 included dogs, ultrasonography identified cholecystitis (75.5%), cholelithiasis (16.3%), and biliary mucocele (8.2%). Bile cultures were positive in 43/49 dogs (87.8%), yielding only aerobic bacteria. Escherichia coli (46.5%) and coagulase-positive Staphylococci (30.2%) were most frequently isolated organisms. However, these findings should be interpreted cautiously due to small subgroup sizes and the exploratory nature of the analysis. Conclusions: In this selected referral population, bacterial isolates were frequently recovered from bile samples, particularly in dogs with cholecystitis. Prospective studies involving larger populations are warranted to confirm these results, define the bacterial prevalence and clinical significance of bacterial colonization or infection, and further refine evidence-based diagnostic and treatment strategies for dogs with extrahepatic biliary disease. Full article