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1.
Blood Adv ; 5(7): 1876-1883, 2021 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-33792630

RESUMO

Assessment of measurable residual disease (MRD) provides prognostic information in acute myeloid leukemia (AML). However, the utility of MRD with venetoclax-based lower intensity regimens is unknown. We analyzed the prognostic value of achieving a negative MRD in older/"unfit" patients with AML receiving first-line therapy with 10-day decitabine and venetoclax. MRD was evaluated in bone marrow specimens using multicolor flow cytometry (sensitivity 0.1%). Ninety-seven patients achieving either a complete remission (CR) or CR with incomplete hematologic recovery (CRi) or morphologic leukemia-free state were included. Median age was 72 years (interquartile range, 68-78 years), and 64% had adverse-risk AML. Eighty-three patients achieved CR/CRi, and 52 (54%) became MRD negative. Median time to becoming MRD negative was 2.0 months (interquartile range, 0.9-3.1 months). Patients becoming MRD negative by 2 months had longer relapse-free survival (RFS) compared with those remaining MRD positive (median RFS, not reached vs 5.2 months; hazard ratio [HR], 0.31; 95% confidence interval [CI], 0.12-0.78; P = .004), longer event-free survival (EFS) (median EFS, not reached vs 5.8 months; HR, 0.25; 95% CI, 0.12-0.55; P < .001), as well as longer overall survival (OS) (median OS, 25.1 vs 7.1 months; HR, 0.23; 95% CI, 0.11-0.51; P < .001). Patients achieving an MRD-negative CR had longer OS compared with those with an inferior response (median OS, 25.1 vs 11.6 months; HR, 0.33; 95% CI, 0.19-0.58; P < .0005). Patients becoming MRD negative within 1 month had an improved OS compared with MRD-positive patients (median OS, 25.1 vs 3.4 months; HR, 0.15; 95% CI, 0.03-0.64; P < .0001). Differential impact of MRD status on survival outcomes persisted at a later 4-month time point of evaluation. In conclusion, MRD-negative status at 1, 2, and 4 months after starting therapy confers significantly better survival in older/unfit patients with AML receiving first-line therapy with 10-day decitabine and venetoclax. This trial was registered at www.clinicaltrials.gov as #NCT03404193.

2.
Cancer ; 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33793970

RESUMO

BACKGROUND: Venetoclax (VEN) combined with the hypomethylating agent (HMA) azacitidine improves survival in patients aged ≥75 years with newly diagnosed acute myeloid leukemia (AML). VEN and HMA treatment can result in prolonged and often profound neutropenia, and this warrants antifungal prophylaxis. Azole antifungals inhibit cytochrome P450 3A4, the primary enzyme responsible for VEN metabolism; this results in VEN dose reductions for each concomitant antifungal. Limited clinical data exist on outcomes for patients treated with VEN, an HMA, and various azoles. METHODS: The time to neutrophil recovery (absolute neutrophil count [ANC] > 1000 cells/mm3 ) and platelet (PLT) recovery (PLT count > 100,000 cells/mm3 ) in 64 patients with newly diagnosed AML who achieved a response after course 1 of VEN plus an HMA were evaluated. HMA therapy included azacitidine (75 mg/m2 intravenously/subcutaneously for 7 days) or decitabine (20 mg/m2 intravenously for 5 or 10 days). RESULTS: Forty-seven patients (73%) received an azole: posaconazole (n = 17; 27%), voriconazole (n = 9; 14%), isavuconazole (n = 20; 31%), or fluconazole (n = 1; 2%). The median time to ANC recovery were similar for patients who did receive an azole (37 days; 95% confidence interval [CI], 34-38 days) and patients who did not receive an azole (39 days; 95% CI, 30 days to not estimable; P = .8). The median time to PLT recovery was significantly longer for patients receiving azoles (28 vs 22 days; P = .01). The median times to ANC recovery (35 vs 38 days) and PLT recovery (26 vs 32 days) were similar with posaconazole and voriconazole. CONCLUSIONS: VEN plus an HMA resulted in neutropenia and thrombocytopenia, with the latter prolonged in patients receiving concomitant azoles. Concomitant posaconazole or voriconazole and VEN (100 mg) resulted in similar ANC and PLT recovery times, suggesting the safety of these dosage combinations during course 1.

3.
Chem Biol Interact ; 340: 109453, 2021 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-33785314

RESUMO

Gut bacterial ß-glucuronidase (GUS) plays a pivotal role in the metabolism and reactivation of a vast of glucuronide conjugates of both endogenous and xenobiotic compounds in the gastrointestinal tract of human, which has been implicated in certain drug-induced gastrointestinal tract (GI) toxicity in clinic. Inhibitors of gut microbial GUS exhibited great potentials in relieving the drug-induced GI toxicity. In this study, Selaginella tamariscina and its major biflavonoid amentoflavone (AMF) were evaluated for their inhibitory activity against Escherichia coli GUS. Two selective probe substrates for GUS (a specific fluorescent probe substrate for GUS, DDAOG and a classical drug substrate for GUS, SN38G) were used in parallel for charactering the inhibition behaviors. Both the extract of S. tamariscina and its major biflavonoid AMF displayed evident inhibitory effects on GUS, and the IC50 values of AMF against GUS mediated DDAOG and SN-38G hydrolysis were 0.62 and 0.49 µM, respectively. Inhibition kinetics studies indicated that AMF showed mixed type inhibition for GUS-mediated DDAOG hydrolysis, while displayed competitive type inhibition against GUS-mediated SN-38G hydrolysis, with the Ki values of 0.24 and 1.25 µM, respectively. Molecular docking studies and molecular dynamics stimulation results clarified the role of amino acid residues Leu361, Ile363, and Glu413 in the inhibition of AMF on GUS. These results provided some foundations for the potential clinical utility of S. tamariscina and its major biflavonoid AMF for treating drug-induced enteropathy.

4.
Diabetes Ther ; 2021 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-33740209

RESUMO

INTRODUCTION: The aim of this study was to clarify the efficacy and safety of metabolic surgery in Chinese patients with type 2 diabetes mellitus (T2DM) and a body mass index (BMI) of 27.5-32.5 kg/m2. METHODS: A total of 99 patients with T2DM were enrolled in this retrospective cohort study. Of these patients, 53 had a BMI of 27.5-32.5 kg/m2 and had undergone metabolic surgery (n = 21) or were on conventional antidiabetic therapy (n = 32)]; 46 had a BMI ≥ 32.5 kg/m2 and all had undergone metabolic surgery. Primary endpoints included the triple endpoint [hemoglobin A1c < 6.5%, low-density lipoprotein cholesterol (LDL-C) < 2.6 mmol/L, and systolic blood pressure (SBP) < 130 mmHg] and successful weight loss 1 year later. Remission of diabetes, glucose and lipid metabolism, medication usage, and adverse events were evaluated. RESULTS: Of patients with BMI 27.5-32.5 kg/m2 undergoing metabolic surgery, 33.33% achieved the composite endpoints, and 100% achieved successful weight loss. This result was similar to that in patients with BMI ≥ 32.5 and better than those with BMI 27.5-32.5 kg/m2 receiving conventional antidiabetic therapy. A significant and similar reduction in BMI, waist circumference, SBP, serum LDL-C, hemoglobin A1c, and uric acid, as well as similar frequency postoperative adverse events, were confirmed in both metabolic surgery groups. Patients with BMI 27.5-32.5 kg/m2 who had undergonemetabolic surgery showed more metabolic improvement than those only receiving medications but they experienced more adverse events. CONCLUSION: A BMI cutoff of 27.5 kg/m2 for metabolic surgery may be suitable for Chinese patients with T2DM.

5.
Cell Death Dis ; 12(4): 314, 2021 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-33762577

RESUMO

Chemotherapeutic agents have been linked to immunogenic cell death (ICD) induction that is capable of augmenting anti-tumor immune surveillance. The cardiac glycoside oleandrin, which inhibits Na+/K+-ATPase pump (NKP), has been shown to suppress breast cancer growth via inducing apoptosis. In the present study, we showed that oleandrin treatment triggered breast cancer cell ICD by inducing calreticulin (CRT) exposure on cell surface and the release of high-mobility group protein B1 (HMGB1), heat shock protein 70/90 (HSP70/90), and adenosine triphosphate (ATP). The maturation and activation of dendritic cells (DCs) were increased by co-culturing with the oleandrin-treated cancer cells, which subsequently enhanced CD8+ T cell cytotoxicity. Murine breast cancer cell line EMT6 was engrafted into BALB/c mice, and tumor-bearing mice were administered with oleandrin intraperitoneally every day. Oleandrin inhibited tumor growth and increased tumor infiltrating lymphocytes including DCs and T cells. Furthermore, the differential mRNA expression incurred by oleandrin was investigated by mRNA sequencing and subsequently confirmed by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. Mechanistically, oleandrin induced endoplasmic reticulum (ER) stress-associated, caspase-independent ICD mainly through PERK/elF2α/ATF4/CHOP pathway. Pharmacological and genetic inhibition of protein kinase R-like ER kinase (PERK) suppressed oleandrin-triggered ICD. Taken together, our findings showed that oleandrin triggered ER stress and induced ICD-mediated immune destruction of breast cancer cells. Oleandrin combined with immune checkpoint inhibitors might improve the efficacy of immunotherapy.

6.
J Enzyme Inhib Med Chem ; 36(1): 737-748, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33682565

RESUMO

Human Cytochrome P450 2J2 (CYP2J2) as an important metabolic enzyme, plays a crucial role in metabolism of polyunsaturated fatty acids (PUFAs). Elevated levels of CYP2J2 have been associated with various types of cancer, and therefore it serves as a potential drug target. Herein, using a high-throughput screening approach based on enzymic activity of CYP2J2, we rapidly and effectively identified a novel natural inhibitor (Piperine, 9a) with IC50 value of 0.44 µM from 108 common herbal medicines. Next, a series of its derivatives were designed and synthesised based on the underlying interactions of Piperine with CYP2J2. As expected, the much stronger inhibitors 9k and 9l were developed and their inhibition activities increased about 10 folds than Piperine with the IC50 values of 40 and 50 nM, respectively. Additionally, the inhibition kinetics illustrated the competitive inhibition types of 9k and 9l towards CYP2J2, and Ki were calculated to be 0.11 and 0.074 µM, respectively. Furthermore, the detailed interaction mechanism towards CYP2J2 was explicated by docking and molecular dynamics, and our results revealed the residue Thr114 and Thr 315 of CYP2J2 were the critical sites of action, moreover the spatial distance between the carbon atom of ligand methylene and Fe atom of iron porphyrin coenzyme was the vital interaction factor towards human CYP2J2.

7.
J Colloid Interface Sci ; 593: 125-132, 2021 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-33744523

RESUMO

Self-assembly of colloidal nanoparticles (NPs) into well-defined superstructures has been recognized as one of the most promising ways to fabricate rationally-designed functional materials for a variety of applications. Introducing hierarchical mesoporosity into NP superstructures will facilitate mass transport while simultaneously enhancing the accessibility of constituent NPs, which is of critical importance for widening their applications in catalysis and energy-related fields. Herein, we develop a colloidal co-assembly strategy to construct mesostructured, carbon-coated Co0.5Fe2.5O4 NP superstructures (M-C@CFOSs), which show great promise as highly efficient electrocatalysts for the oxygen evolution reaction (OER). Specifically, organically-stabilized SiO2 NPs are employed as both building blocks and sacrificial template, which co-assemble with Co0.5Fe2.5O4 NPs to afford binary NP superstructures through a solvent drying process. M-C@CFOSs are obtainable after in situ ligand carbonization followed by the selective removal of SiO2 NPs. The hierarchical mesoporous structure of M-C@CFOSs, combined with the conformal graphitic carbon coating derived from the native organic ligands, significantly improves their electrocatalytic performance as OER electrocatalysts when compared with nonporous Co0.5Fe2.5O4 NP superstructures. This work establishes a new and facile approach for designing NP superstructures with hierarchical mesoporosity, which may find wide applications in energy storage and conversion.

8.
Bioresour Technol ; 329: 124869, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33639383

RESUMO

Removing pollutants and producing high value-added products are essential steps for sustainable disposal and utilization of biogas residues. Here, a coupled thermophilic composting and vermicomposting process was used to remove Cr from biogas residues, and the composting products were co-fermented with the plant growth-promoting fungus Trichoderma to produce high value-added biofertilizers. The results showed that thermophilic composting for 37 d markedly increased the total content of Cr but decreased the percentage of available Cr fractions. Synchrotron-radiation-based observations further provided direct evidence of the binding sites to support the results from traditional sequential extraction. At a density of 60 g earthworm/kg biogas residues, vermicomposting removed 23-31% of Cr from biogas residues. After vermicomposting, co-fermentation of biogas residues and Trichoderma was optimized, in which Trichoderma spores were 2-5 × 108 cfu/g substrates. Together, coupling thermophilic composting and vermicomposting processes is a promising technique to remove a portion of heavy metals from biogas residues.


Assuntos
Compostagem , Oligoquetos , Poluentes do Solo , Animais , Biocombustíveis , Solo , Poluentes do Solo/análise
9.
Stat Med ; 40(8): 2037-2054, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33540472

RESUMO

Development of cancer screening biomarkers usually follows the Early Detection Research Network 5-Phase guideline in Pepe et al. A key feature of this guide is that the phased development follows a sequential order, moving to the next phase only when the current phase study is complete and has met its target performance. Motivated by a newly funded Newly onset Diabetes cohort study, we propose a design evaluating new biomarkers to discriminate between cases and controls in the presence of an existing screening test. The proposed design achieves two goals: (1) avoiding bias in estimating sensitivity or specificity in predicting cancer at a given time period prior to clinical diagnosis, using data from both screening detected cancers in Phase IV study and clinically diagnosed cancers in Phase III study; and (2) building a panel with biomarkers for Phase III and IV studies based on all data. A simulation study shows that the proposed design outperforms both a conventional method using data in Phase III arm only and a naive method using data in Phase III and IV arms ignoring the difference between the time of screening the detected cancer and the time of clinical diagnosis. The proposed design yields a smaller standard error of the estimation and increases the statistical power to confirm biomarker performance. This proposed method has the potential to shorten the cancer screening biomarker development process, use resources more effectively, and bring benefits to patients quickly.

11.
Nat Prod Res ; : 1-8, 2021 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-33538200

RESUMO

Sargentodoxa cuneata (Oliv.) Rehd. et Wils is a traditional Chinese medicine to treat acute appendicitis, rheumarthritis, abdominal pain, and painful menstruation for a long history. The investigation of S. cuneata led to the isolation and identification of twenty-three secondary metabolites, including two new compounds, sargentodoxosides A (1) and B (2), and twenty-one known ones (3-23). Their structural characterization was conducted by HRESIMS, 1 D and 2 D NMR spectra. All the isolated compounds were assayed for their agonistic activities against the farnesoid X receptor (FXR). Nine of the isolated compounds displayed significant agonistic effects against FXR at 0.1 µM, suggesting that they could be served as potential agents for the development of FXR agonists.

12.
Sci Rep ; 11(1): 2883, 2021 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-33558592

RESUMO

For the purpose of assessing the radiation dose of the victims involved in the nuclear emergency or radiation accident, a new type of X-band EPR resonant cavity for in vivo fingernail EPR dosimetry was designed and a homemade EPR spectrometer for in vivo fingernail detection was constructed. The microwave resonant mode of the cavity was rectangular TE101, and there was a narrow aperture for fingernail detection opened on the cavity's wall at the position of high detection sensitivity. The DPPH dot sample and the fingernail samples were measured based on the in vivo fingernail EPR spectrometer. The measurements of the DPPH dot sample verified the preliminary functional applicable of the EPR spectrometer and illustrated the microwave power and modulation response features. The fingernails after irradiation by gamma-ray were measured and the radiation-induced signal was acquired. The results indicated that the cavity and the in vivo EPR dosimeter instrument was able to detect the radiation-induced signal in irradiated fingernail, and preliminarily verified the basic function of the instrument and its potential for emergency dose estimate after a radiation accident.

13.
Biometrics ; 2021 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-33559881

RESUMO

Systematic reviews and meta-analyses synthesize results from well-conducted studies to optimize healthcare decision-making. Network meta-analysis (NMA) is particularly useful for improving precision, drawing new comparisons, and ranking multiple interventions. However, recommendations can be misled if published results are a selective sample of what has been collected by trialists, particularly when publication status is related to the significance of the findings. Unfortunately, the missing-not-at-random nature of this problem and the numerous parameters involved in modeling NMAs pose unique computational challenges to quantifying and correcting for publication bias, such that sensitivity analysis is used in practice. Motivated by this important methodological gap, we developed a novel and stable expectation-maximization (EM) algorithm to correct for publication bias in the network setting. We validate the method through simulation studies and show that it achieves substantial bias reduction in small to moderately sized NMAs. We also calibrate the method against a Bayesian analysis of a published NMA on antiplatlet therapies for maintaining vascular patency.

14.
Aging (Albany NY) ; 13(4): 6214-6227, 2021 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-33591942

RESUMO

The prognosis of lung cancer patients with different clinical stages is significantly different. The 5-year survival of stage IA groups can exceed 90%, while patients with stage IV can be less than 10%. Therefore, early diagnosis is extremely important for lung cancer patients. This research focused on various diagnosis methods of early lung cancer, including imaging screening, bronchoscopy, and emerging potential liquid biopsies, as well as volatile organic compounds, autoantibodies, aiming to improve the early diagnosis rate and explore feasible and effective early diagnosis strategies.

15.
Artigo em Inglês | MEDLINE | ID: mdl-33481394

RESUMO

PURPOSE: Retinoblastoma (RB) is the most common intraocular cancer and is associated with lifelong risks of developing a second primary cancer, especially in patients with hereditary RB and/or childhood exposure to radiotherapy. METHODS: The study included all consecutive patients with a history of RB treated for a second primary cancer during 1994-2018. Patient demographics and characteristics of the primary RB and second primary cancer were examined. The associations among radiation or chemotherapy exposure as a treatment for RB, unilateral versus bilateral status, types and multiplicity of second primary cancers, and survival after diagnosis of second primary cancer were analyzed. RESULTS: A wide spectrum of second primary cancer types was identified from 62 eligible patients (30 males and 32 females), including sarcoma, breast cancer, various skin cancers, gastrointestinal and genitourinary cancers, and endocrine cancers. Of all patients who had second primary cancers, 40 patients (65%) had bilateral RB and 17 patients (27%) had unilateral RB. Thirty-five patients (56%) who developed second primary cancers received radiation therapy during childhood as the treatment of RB, and 17 patients (27%) received chemotherapy for the treatment of RB. The 5-year and 10-year survival rates for RB patients diagnosed with a second primary cancer were 54.0% and 36.0%, respectively. The median age of onset of second primary cancer among RB survivors was 36.6 years. CONCLUSIONS: In contrast to previous studies, we found a broader spectrum of second primary cancer types. All RB survivors, regardless of unilateral or bilateral status, should undergo strict cancer surveillance particularly as they approach the fourth decade of life.

16.
J Agric Food Chem ; 69(2): 836-845, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33416310

RESUMO

Persimmon (Diospyros kaki Thunb.) fruit is unique due to the continuous accumulation of soluble tannins during fruit development in most cultivars, which causes undesired astringency. High-CO2 treatment was the most effective widely used method for astringency removal. However, differential effects of high-CO2 treatment between cultivars were observed and the molecular basis remained inclusive. Previously, one cultivar ("Luoyangfangtianshengshi," LYFTSS) showed rapid deastringency, while two cultivars ("Shijiazhuanglianhuashi," SJZLHS; "Laopige," LPG) showed slow deastringency in response to high-CO2 (95% CO2) treatment. In this study, the metabolites (acetaldehyde and ethanol) related to deastringency were further analyzed and both acetaldehyde and ethanol were higher in SJZLHS and LYFTSS than that in LPG, where acetaldehyde was undetectable. Based on the RNA-seq data, the weighted gene coexpression network analysis (WGCNA) revealed that one module, comprised of 1773 unigenes, significantly correlated with the contents of acetaldehyde and ethanol (P < 0.001). Further analysis based on the acetaldehyde metabolism pathway indicated that the differentially expressed structural genes, including previously characterized DkADH and DkPDC and also their upstream members (e.g., PFK, phosphofructokinase), showed positive correlations with acetaldehyde production. Quantitative analysis of the precursor substances indicated that sucrose, glucose, and fructose exhibited limited differences between cultivar except for malic acid. However, the content of malic acid is much less than the total soluble sugar content. To verify the correlations between these genes and acetaldehyde production, the fruit from 14 more cultivars were collected and treated with high CO2. After the treatment, acetaldehyde contents in different cultivars ranked in 30.4-255.5 µg/g FW. Real-time polymerase chain reaction (PCR) and correlation analysis indicated that the EVM0002315 (PFK) gene, belonging to carbohydrate metabolism, was significantly correlated with acetaldehyde content in fruit. Thus, it could be proposed that the differentially expressed carbohydrate metabolism related genes (especially PFK) are the basis for the variance of acetaldehyde production among different persimmon cultivars.


Assuntos
Acetaldeído/metabolismo , Metabolismo dos Carboidratos , Dióxido de Carbono/farmacologia , Diospyros/efeitos dos fármacos , Diospyros/genética , Diospyros/química , Diospyros/metabolismo , Frutas/química , Frutas/efeitos dos fármacos , Frutas/genética , Frutas/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regiões Promotoras Genéticas , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
18.
Water Res ; 190: 116774, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33387947

RESUMO

Acetate is a pivotal intermediate product during anaerobic decomposition of organic matter. Its generation and consumption network is quite complex, which almost covers the most steps in anaerobic digestion (AD) process. Besides acidogenesis, acetogenesis and methanogenesis, syntrophic acetate oxidation (SAO) replaced acetoclastic methanogenesis to release the inhibition of AD at some special conditions, and the importance of considering homoacetogenesis had also been proved when analysing anaerobic fermentations. Syntrophic acetate-oxidizing bacteria (SAOB), with function of SAO, can survive under high temperature and ammonia/ volatile fatty acids (VFAs) concentrations, while, homoacetogens, performed homoacetogenesis, are more active under acidic, alkaline and low temperature (10°C-20°C) conditions, This review summarized the roles of SAO and homoacetogenesis in AD process, which contains the biochemical reactions, metabolism pathways, physiological characteristics and energy conservation of functional bacteria. The specific roles of these two processes in the subprocess of AD (i.e., acidogenesis, acetogenesis and methanogenesis) were also analyzed in detail. A two phases anaerobic digester is proposed for protein-rich waste(water) treatment by enhancing the functions of homoacetogens and SAOB compared to the traditional two-phases anaerobic digesters, in which the first phase is fermentation phase including acidogens and homoacetogens for acetate production, and second phase is a mixed culture coupling syntrophic fatty acids bacteria, SAOB and hydrogenotrophic methanogens for methane production. This review provides a new insight into the network on production and consumption of acetate in AD process.


Assuntos
Acetatos , Metano , Anaerobiose , Bactérias , Reatores Biológicos , Oxirredução
19.
Bioresour Technol ; 324: 124671, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33450626

RESUMO

Conductive materials presented promising advantages for enhancing anaerobic digestion (AD) performance. This study evaluated the effects of activated carbon (AC) and nano-zero-valent iron (nZVI) on the acidogenesis and whole AD to explore their potential mechanisms. AC increased the content of lactic and propionic acids in acidogenesis. nZVI increased the production of formic acid, acetic acid and H2 in acidogenesis, thus significantly promoted the methane yield in the whole AD. Mechanism exploration proved that AC enriched Trichococcus, and norank_f__Bacteroidetes_vadinHA17, and then improved the activity of enzymes involved in the production of lactic and propionic acids. nZVI buffered the pH to increase the activity of pyruvate formate-lyase (PFL) in formic acid production. Furthermore, nZVI enriched the Methanobacterium which use H2 and formic acid as substrate. The research paves pathway for the efficient enhancement of conductive materials added novel AD process.


Assuntos
Carvão Vegetal , Ferro , Anaerobiose , Metano , Esgotos
20.
Sci Total Environ ; 754: 142425, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33254934

RESUMO

Anaerobic digestion (AD) is widely used on waste treatment for its great capability of organic degradation and energy recovery. Accumulation of volatile fatty acids (VFAs) caused by impact loadings often leads to the acidification and failure of AD systems. Bioaugmentation is a promising way to accelerate VFA degradation but the succession of microbial communities usually caused unpredictable consequences. In this study, we used the sludge previously acclimated with VFAs for the bioaugmentation of an acidified anaerobic digestion system and increased the methane yield by 8.03-9.59 times. To see how the succession of microbial communities affected bioaugmentation, dual-chamber devices separated by membrane filters were used to control the interactions between the acidified and acclimated sludges. The experimental group with separated sludges showed significant advantages of VFA consumption (5.5 times less final VFA residue than the control), while the group with mixed sludge produced more methane (4.0 times higher final methane yield than the control). Microbial community analysis further highlighted the great influences of microbial interaction on the differentiation of metabolic pathways. Acetoclastic methanogens from the acclimated sludge acted as the main contributors to pH neutralization and methane production during the early phase of bioaugmentation, and maintained active in the mixed sludge but degenerated in the separated sludges where interactions between sludge microbiotas were limited. Instead, syntrophic butyrate and acetate oxidation coupled with nitrate and sulfate reduction was enriched in the separated sludges, which lowered the methane conversion rate and would cause the failure of bioaugmentation. Our study revealed the importance of microbial interactions and the functionality of enriched microbes, as well as the potential strategies to optimize the durability and efficiency of bioaugmentation.


Assuntos
Reatores Biológicos , Microbiota , Anaerobiose , Ácidos Graxos Voláteis , Redes e Vias Metabólicas , Metano , Interações Microbianas , Esgotos
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