Fermentation-Basel
·
2023
·Vol. 9
·期 5
·465
·
IF 3.7
Bei Li,Chiqian Zhang,Cong Jin,Jinhua Wu,Ping Li
The leachate from municipal solid waste transfer stations has a complex composition of pollutants, contains high concentrations of organic matter, and produces odors. The anaerobic digestion of leachate generates excessive volatile organic acids (VFAs), acidifying the digestate and destabilizing or even collapsing the anaerobic process. To solve these issues, we set up a facultative anaerobic system with air exposure and an obligate anaerobic system without air exposure to explore the impact of anaerobic degree on intermediate accumulation and anaerobic process stability. When the organic loading raised from 0.6 to 6.0 kg COD/(m3·d), VFA accumulation in the facultative system peaked at 3.30 g COD/L, and the chemical oxygen demand (COD) removal rate dropped from 95% to 60%. By contrast, the obligate system remained stable, with VFA concentrations below 0.50 g COD/L and COD removal rates between 85% and 99%. Microbial sequencing shows that VFA-oxidizing bacteria enhanced VFA degradation, such asSyntrophomonasandSmithella, which increased from 4.62% and 0.76% in the facultative system to 17.64% and 0.88% in the obligate system, respectively. Coenzyme F420 concentration as an indicator of methanogenic activity was 50% higher in the obligate system. Therefore, an obligate anaerobic system is promising to alleviate acidification for stable anaerobic digestion of leachate.Keywords:anaerobic digestion;anaerobic degree;loading fluctuation;VFA accumulation;fresh leachate
研究领域:
环境工程
·
废物管理
·
微生物学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2023
·
IF 8.7
Jianan Niu,Xin Kong,Qingxia Li,Yongmei Zhang,Jin Yuan,Jianguo Liu,Yifeng Zhang
Dosing zero valent iron (ZVI) or sodium hydroxide (NaOH) is the common method of addressing acidification in anaerobic digestion (AD) systems; however, few studies have discussed and compared their effects on microbial metabolism. In the present study, microbial syntrophy and metabolic pathways under ZVI and NaOH regulation are comparatively analyzed through microbial network analysis and metagenomic/metaproteomic analyses. CH 4 yield in the ZVI reactor was 414 mL/gVS, an increase of 23% when compared with that in the reactor with NaOH dosing (336 mL/gVS). The methanogenesis recovery period in the ZVI reactor (37 days) was shorter than that in the NaOH reactor (48 days). Co-occurrence networks indicated that ZVI promoted Methanoculleus and Methanosarcina to establish a complex syntrophic association with SAO bacteria ( Syntrophaceticus and Aminobacterium ) and syntrophic acetogens ( Syntrophomonas ), strengthening SAO-hydrogenotrophic methanogenesis (HM) and acetoclastic methanogenesis (AM) pathways simultaneously. Metagenomic analysis showed that the relative abundance of mcrA and fwdB in the ZVI reactor was higher 27% than that in the NaOH reactor. Furthermore, through metaproteomics analysis, much more enzymes related to glucose degradation, bioconversion of butyric acid and pyruvate, conversion of formate and acetate to CO 2 , and production of CH 4 from acetate and CO 2 were significantly upregulated under ZVI regulation than under NaOH regulation (fold change relative to control [FC] > 1.5, p < 0.05). The results of the present study enhance our understanding of methanogenic mechanisms under the regulation of ZVI, providing a theoretical basis for its practical application in AD systems experiencing VFA suppression.
研究领域:
环境微生物学
·
生物技术
·
厌氧消化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Frontiers of Environmental Science & Engineering
·
2021
·Vol. 16
·期 8
·1-14
·
IF 4.357
Luo Jingyang,Fang Shiyu,Huang Wenxuan,Wang Feng,Zhang Le,Fang Fang,Cao Jiashun,Wu Yang,Wang Dongbo
Surfactants were expected to exhibit positive effects on the waste activated sludge (WAS) disposal. However, the systematic comparison of different categories of surfactants on the WAS fermentation and the functional mechanisms, especially microbial metabolic traits, have not yet been precisely explored. This study revealed the positive effects of different surfactants on the volatile fatty acid (VFA) production, which followed the order of alkyl polysaccharides (APG)>sodium dodecylbenzene sulfonate (SDBS)>hexadecyl trimethyl ammonium bromide (HTAB). Mechanistic exploration found that the presence of different surfactants improved solubilization and hydrolysis steps, and then contributed to the subsequent acidification with different efficiencies. The functional microorganisms associated with VFA generation were enriched in surfactant-conditioned reactors. Metagenomic analysis further indicated that the key genes involved in the particular process of VFA generation were over-expressed. The simultaneous bioavailable substrate improvement, functional bacterial enrichment, and metabolic activity upregulation induced by different surfactants jointly contributed to VFA promotion during WAS fermentation. This study could provide a comprehensive realization of surfactants’ impacts on the WAS fermentation process, and more importantly, it reminded the public to discern the distinct interplaying effects induced by different chemicals in regulating the WAS disposal and resource recovery.
研究领域:
环境工程
·
微生物学
·
生物技术
✓ 已验证
DOI
高影响因子
WATER RESEARCH
·
2018
·
IF 7.051
Long Huang,Zhiqiang Chen,Dandan Xiong,Qinxue Wen,Ye Ji
As the main intermediate metabolite in anaerobic digestion of wasted activated sludge (WAS), volatile fatty acids (VFAs) are proper substrate for mixed culture (MC) polyhydroxyalkanoate (PHA) synthesis. To further optimize the performance of MC PHA production process, VFA _odd (i.e., VFA with odd carbon atoms) oriented acidification process was proposed and conducted in this study. Three regulation factors including reaction pH, fraction of added β-cyclodextrin (β-CD) and glycerol were selected and response surface methodology (RSM) was used to enhance and effectively regulate the VFA _odd production while maintaining enough acidification degree in the WAS acidification. High percentage of VFA _odd (larger than 60% and dominated by propionic acid) can be obtained in the operating condition area with glycerol addition ratio (quantified by C/N) ranging from 15 to 20 and reaction pH ranging from 8.0 to 9.5 when β-CD addition was held at zero level (0.2 g/gTSS) according to the RSM. Semi-continuous acidification and MC PHA production assays further verified the reliability and effectiveness of the VFA _odd oriented acidification strategy. Microbial function group related to propionic acid production (G prop ) was defined based on the relationships between system function and microbial community structure, and 13 frequent species were found being involved in the G prop . Roles of the group members in the oriented acidification were analyzed to understand the mechanisms of the regulation of VFA _odd production at microbial ecological level. A synergistic effect of WAS and glycerol on the VFA _odd production in the acidification process was revealed based on the ecological analysis.
研究领域:
环境工程
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Animals
·
2020
·Vol. 10
·期 2
·223
·
IF 2.323
Lijun Wang,Guangning Zhang,Yang Li,Yonggen Zhang
Simple SummaryThe rumen is well known as a natural bioreactor for highly efficient degradation of fibers, and rumen microbes play an important role on fiber degradation. Carbohydrates are fermented by a variety of bacteria in the rumen and transformed into volatile fatty acids (VFAs) by the corresponding enzymes. However, the content of forage in the diet affects the metabolism of cellulose degradation and VFA production. Therefore, we combine metabolism and metagenomics to explore the effects of High forage/concentrate diets and sampling time on enzymes and microorganisms involved in the metabolism of fiber and VFA in cow rumen. This study showed that propionate formation via the succinic pathway, in which succinate CoA synthetase (EC 6.2.1.5) and propionyl CoA carboxylase (EC 2.8.3.1) were key enzymes. Butyrate formation via the succinic pathway, in which phosphate butyryltransferase (EC 2.3.1.19), butyrate kinase (EC 2.7.2.7) and pyruvate ferredoxin oxidoreductase (EC 1.2.7.1) are the important enzymes. The microorganisms are mainly affected by diet and sampling time.AbstractThe objectives of this study were to investigate the difference in the mechanism of VFAs production combined with macrogenome technology under different forage-to-concentrate ratios and sampling times. Six ruminally cannulated Holstein cows were used in a randomized complete block design. The high forage (HF) and high concentrate (HC) diets contained 70 and 35% dietary forage, respectively. The results showed that pH was affected by sampling time, at 4 h after feeding had lower value. Excepted for acetate, the VFAs was increased with forage decreased. Propionate formation via the succinic pathway, in which succinate CoA synthetase (EC 6.2.1.5) and propionyl CoA carboxylase (EC 2.8.3.1) were key enzymes, and significantly higher in HC treatment than in HF treatment,Selenomonas,Ruminobacter,Prevotella, andClostridiumwere the main microorganism that encodes these key enzymes. Butyrate formation via the succinic pathway, in which phosphate butyryltransferase (EC 2.3.1.19), butyrate kinase (EC 2.7.2.7) and pyruvate ferredoxin oxidoreductase (EC 1.2.7.1) are the important enzymes,PrevotellaandBacteroidesplayed important role in encodes these key enzymes. This research gave a further explanation on the metabolic pathways of VFAs, and microorganisms involved in VFAs production under different F:C ration, which could further reveal integrative information of rumen function.Keywords:metagenomics;fiber decomposition;volatile fatty acid production;fibrinolytic bacteria;gene expression
研究领域:
微生物学
·
动物营养学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Shiyu Fang,Yisong Zhu,Wangbei Cao,Qian Wu,Wenxuan Huang,Feng Wang,Xiaoshi Cheng,Jiashun Cao,Jingyang Luo,Yang Wu
Anaerobic fermentation is a low-carbon strategy for waste activated sludge (WAS) treatment with resource recovery. This study compared the effects of potassium permanganate (PM) and calcium sulfite-assisted PM (PM/CS) pretreatment on volatile fatty acids (VFAs) production during WAS fermentation. The effects of combined PM/CS on the total VFAs production were observed to be inferior to sole PM (2689 versus 3507 mg COD/L), but PM/CS pretreatment resulted in acetate-enriched VFAs (88.2% ratio) with improved sludge dewatering. The scavenging effects of interfering compounds on free radicals, which are previously speculated for extracellular polymeric substances (EPS) disruption, and the EPS-binding effects of Ca 2+ in PM/CS reactors might both restrain the effective WAS solubilization and hydrolysis efficiencies in comparison with that of PM, and thus resulted in the reduced VFAs production. Moreover, both PM and PM/CS pretreatment altered the microbial community structure and metabolic traits, which were beneficial to the VFAs generation. However, the PM/CS pretreatment was more conducive to the enrichment of acetate-producing bacteria ( e.g., Proteiniclasticum and Christensenellaceae_R_7_group ) and acetate-forming metabolic functions ( e.g., pyruvate metabolism and propanoate and butanoate degradation). Also, methanogenesis, which is an acetate-consumption process, was remarkably inhibited in PM/CS reactor, thereby promoting acetic acid accumulation effectively. This study demonstrated the distinct effects of different PM-based pretreatment on WAS fermentation and provided guidance on the appropriate pretreatment selection for WAS disposal.
研究领域:
环境工程
·
微生物学
·
废物管理
✓ 已验证
DOI
高影响因子
Sensors & Diagnostics
·
2023
·Vol. 2
·期 5
·1292-1301
·
IF 0
Yu Lu,Ruihua Fei,Jiahe Zhang,Geng Zhu,Xiufang Mo,Yu Wan,Yan Huang,Qingjiang Sun,Dianhuai Meng,Xiangwei Zhao
The clinical symptoms of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are similar to those of influenza A infection. Therefore, accurate diagnosis of SARS-CoV-2 and influenza A in the early infection stage is essential for appropriate clinical treatment. In this work, a vertical flow assay (VFA) device based on Au@Ag@Au core–shell SERS nanotags and anodic aluminum oxide (AAO) was proposed to diagnose and distinguish between SARS-CoV-2 and influenza A at the same time. Antibodies paired with SARS-CoV-2 and influenza A were immobilized simultaneously on the AAO. In the presence of SARS-CoV-2 or influenza A antigens, sandwich immune-complexes were formed on the AAO and the corresponding SERS signals of nanotags could be detected. The whole detection process took only about 15 minutes, taking comparable or even shorter time than reported POCT antigen assays. The detection limit reached 0.47 pg ml−1 for SARS-CoV-2 nucleocapsid protein (NP) and 0.62 pg ml−1 for influenza A antigen. The clinical feasibility of the proposed VFA device was validated by testing clinical throat swab samples (3 SARS-CoV-2 positive samples and 17 negative samples). Real sample analysis indicated a well-distinguished positive/negative sample group. Conceptually, this VFA device is a potential POCT diagnosis tool for determining if a suspected patient is infected with SARS-CoV-2 or influenza A.
研究领域:
医学诊断
·
分析化学
·
纳米技术
·
公共卫生
✓ 已验证
DOI
ANALYST
·
2024
·
IF 3.6
Zhiqi Gu,Hui Chang,Guo Yang,Boxuan Xu,Bin Miao,Jiadong Li
Vertical flow assay (VFA) is an effective point-of-care (POC) diagnostic tool for widespread applications. Nevertheless, the lack of multi-target detection and multi-signal readout capability still remain challenges. Herein, a brand new VFA scheme for multi-target saliva detection based on electronic-tags was proposed, where AlGaN/GaN HEMT sensors modified with different bio-receptors as electronic tags endowed the VFA a multi-target detection capability. In addition, the use of electronic tags instead of optical tags made that the VFA could simultaneously carry out direct multi-target readout, which ensure the effective POC diagnostic of saliva analysis. Moreover, by integrating a hydrophilically optimized micro-sieve, impurities like sticky filaments, epidermal cells and other large-scale charged particles in saliva were effectively screened, which enabled the direct detection of saliva by AlGaN/GaN HEMT sensors. Glucose, urea, and cortisol were selected to verified the feasibility of the multi-target e-VFA scheme, results displayed that the limit-of-detection (LOD) was as low as 100 aM. The linear response was demonstrated in the dynamic range of 100 aM - 100 μM, the specificity and long-term stability and the validity of the actual saliva test were also verified. These results demonstrated that the as-proposed e-VFA had potential application in saliva detection for multi-target simultaneous detection, and it is expected to achieve the real-time detection of more biological targets in saliva.
研究领域:
生物医学工程
·
诊断学
·
传感器技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
·
2021
·
IF 9.642
Pingbo Wang,Meiying Ye,Yue Cui,Xiong Xiao,Dexun Zou,Rongxin Guo,Yanping Liu
Two-phase high-solid digestion is conducive to the degradation of food waste. In this study, Fe/C was added in high-solid digestion in different acidification and/or methanogenic phase. The experimental results indicated that it significantly increased the cumulative yield of biomethane. When Fe/C was added to the acidification phase only and both the acidification and methanogenic phases, the biomethane yield reached 474.07 ± 7.03 and 475.47 ± 4.68 mL·g VS −1 , respectively, and the biodegradation rate reached 87.30% and 87.58%, respectively, indicating that Fe/C had mainly effect on the performance of acidification phase. In a two-phase anaerobic fermentation system, the activity of dehydrogenases and the concentration of coenzyme F 420 were 2.23–2.95 mg·g −1 ·h −1 and 0.0063–0.0294 mol·g −1 volatile solids, respectively. Additionally, the archaeal communities production pathway of methane from using acetic acid to using hydrogen as the reactant.
研究领域:
环境工程
·
微生物学
·
废物管理
·
生物技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）