ENVIRONMENTAL RESEARCH
·
2021
·
IF 6.498
Zhen Li,Shuo Chen,Bingchuan Liu,Jiakuan Yang,Sha Liang,Keke Xiao,Jingping Hu,Huijie Hou
This study investigated a novel sodium iron chlorophyllin-H 2 O 2 (SIC–H 2 O 2 ) sludge pretreatment strategy before anaerobic digestion to enhance methane production. The efficiencies and mechanism of the proposed strategy to enhance sludge biodegradability were explored. The SIC–H 2 O 2 pretreatment could enhance the oxidation performance for sludge floc disintegration to dissociate TB-EPS into S-EPS increased SCOD to 521.38 mg/L. The increase of solubilization and release of EPS with the pretreatment facilitate the biogas production at 702 L kg −1 VS, which was 3-folds of the control and significantly higher than other pretreatments. The result of excitation–emission matrix and parallel factor (EEM-PARAFAC) analysis showed that the SIC–H 2 O 2 pretreatment enhanced the dissociation of TB-EPS fractions, especially the protein-like and soluble microbial by-product-like substances. Electron paramagnetic resonance (EPR) results provided evidence for homolytic catalysis H 2 O 2 for the generation OH and the production of high-valent (Por)Fe IV (O) intermediates. Synergistic effects of reactive oxygen species ( OH, H 2 O 2 and /HO 2 ) and (Por)Fe IV (O) enhanced the EPS disintegration during SIC–H 2 O 2 pretreatment. The mixed-acid type fermentation provided continuous VFAs supply under the enrichment of Chloroflexi and Actinobacteria and multiplication Methanosaeta also promoted methane production. This research provides a feasible pretreatment strategy increase sludge biodegradability and enhance biogas production in the anaerobic digestion process.
研究领域:
环境工程
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废物管理
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生物技术
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化学工程
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DOI
PubMed
高影响因子
FOOD RESEARCH INTERNATIONAL
·
2025
·
IF 8
Ziqi Liu,Yuechong Liu,Jian He,Xiaoyan Pei,Yixin Lin,Marciane Magnani,Donghong Liu,Tian Ding,Jinsong Feng
The bacterial contamination and failure of pasteurization are leading threats to the safety of dairy productions. Milk contains a large quantity of fat which supports bacterial growth but its influence on pasteurization efficacy and biofilm formation remains poorly understood. In this study, we first demonstrate that the inactivation of Salmonella during pasteurization is significantly less effective in whole milk compared to skim milk, with the D-value increasing from 0.60 min in skim milk to 0.67 min in whole milk ( P = 0.0047). In whole milk, Salmonella biofilms form greater biomass and display a distinct architecture from biofilms in skim milk. Specifically, Salmonella in whole milk was embedded within the extracellular polymeric substances (EPS), while cells in skim milk biofilms were sparsely distributed. Raman spectroscopy showed that biofilms formed in whole milk possess a distinctly higher lipid content. Therefore, we hypothesized that the thermal tolerance of Salmonella in whole milk was directly linked to its physical interaction with milkfat. Confocal laser scanning microscopy showed an increase from 26.1 % to 86.1 % of the fraction of Salmonella co-localizing with milkfat after 12 h of incubation in whole milk. Lipase treatment (200 units/mL) on whole milk reduced biofilm formation and improved the efficacy of thermal inactivation. Our findings demonstrate the milkfat acts as a physical scaffold, facilitating bacterial aggregation and the formation of a protective, lipid-rich biofilm matrix enhancing Salmonella survival during pasteurization. These insights should inform pasteurization strategies of high-fat dairy products to ensure food safety.
研究领域:
食品微生物学
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食品安全
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应用微生物学
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乳品科学
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产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Lu Bai,Guanjun Wang,Dongdong Ge,Yanting Dong,Hui Wang,Yuhui Wang,Nanwen Zhu,Haiping Yuan
Dewatering treatment is an essential step to diminish sludge volume, cut down transportation costs, and improve subsequent disposal efficiency. In this study, ozone-peroxymonosulfate (O 3 /PMS) oxidation process was employed to ameliorate sludge dewaterability. Sludge capillary suction time (CST) and water content (Wc) of dewatered sludge cake could reduce from 70.5 s and 81.93% to 26.7 s and 65.65%, respectively, under the optimal dosage of 30 mg/g TS O 3 and 0.4 mmol/g TS PMS. The increased sludge zeta potential , particle size, and fluidity promoted sludge dewatering performance apparently. The decreased hydrophilic, fluorescent EPS components and proteins/peptides-like + Lipids percentage in EPS as well as the ratio of α-helix/(β-sheet + random coil) of treated EPS protein secondary structure was greatly responsible for the enhanced sludge dewaterability. SO 4 − and OH were detected in ozone-peroxymonosulfate process to crack sludge flocs, eliminate hydrophilic substances and liberate bound water. Moreover, the concentrations of both heavy metals and polycyclic aromatic hydrocarbons (PAHs) of sludge after O 3 /PMS conditioning were decreased, and the stability and toxicity of heavy metals were also reduced, except Zn. In conclusion, this work offered a comprehensive insight based on ozone-peroxymonosulfate (O 3 /PMS) advanced oxidation for improving the sludge dewaterability and environmental implication.
研究领域:
环境工程
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污水处理
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污泥管理
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DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
·
IF 10.753
Dan Zhou,Mengmeng Liang,Yonglian Xia,Chao Li,Mingzheng Huang,Shuming Peng,Yi Huang
Extracellular polymeric substances (EPS) are high-molecular polymers secreted by microbes and play essential roles in metallic biogeochemical cycling. Previous studies demonstrated the reducing capacity of the functional groups on EPS for metal reduction. However, the roles of different EPS components in vanadium speciation and their responsible reducing substances for vanadium reduction are still unknown. In this study, the EPS of Bacillus sp. PFYN01 was fractionated via ultrafiltration into six components with different kDa (EPS >100 , EPS 100 – 50 , EPS 50 – 30 , EPS 30 – 10 , EPS 10 – 3 , and EPS <3 ). Batch reduction experiments of the intact cells, EPS-free cells, the pristine and fractionated EPS with V 5+ were conducted and characterized. The results demonstrated that the extracellular reduction of V 5+ into V 4+ by EPS was the major reduction process. Among the functional groups in EPS, C=O/C-N of amide in protein/polypeptide and C O of carboxyl in fulvic acid-like substances might act as the reductants for V 5+ , while C O in polysaccharide molecules and P O in phosphodiester played a key role in the adsorption process. The intracellular reduction was via translocating V 5+ into the cells and releasing V 4+ by the intracellular reductases. The reducing capacity of the fractionated EPS followed a sequence of EPS <3 > EPS 10 – 3 > EPS 50 – 30 > EPS 100 – 50 > EPS 30 – 10 > EPS >100 . The small molecules of fulvic acid-like substances and amino acids were responsible for the high reducing capacity of EPS <3 . EPS >100 had the lowest reducing capacity due to its macromolecular structure decreasing the exposure of the reactive sites. In addition to reduction, those intermediate EPS components may also have supporting functions, such as connecting protein skeletons and increasing the specific surface area of EPS. Therefore, the diverse effects of the EPS components cannot be neglected in vanadium biogeochemical cycling.
研究领域:
环境微生物学
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生物地球化学
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水化学
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微生物生态学
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DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
·
2023
·
IF 11.4
Haolian Xu,Hong Wang,Zixuan Liang,Hongbin Chen,Donghai Yang,Zhenzhen Tang,Xiaohu Dai
This study posed a novel biomimetic flocculation approach, aiming to efficiently harvest high-quality biomass of Scenedesmus quadricauda cultured with anaerobic digestate. Here, that poly(diallyldimethylammonium chloride) (PDADMAC) could serve as mimetic silicified proteins to spontaneously incorporate nanosilica onto microalgal cells, imparting diatom-like characteristics to S. quadricauda . Compared to the exponential growth phase (day 3), the highest harvesting efficiency (93.49%) was obtained at a lower dosage of PDADMAC (5 mg/g) in the stationary phase (day 6), which was attributed to changes in properties and composition of microalgal LB-EPS. On day 6, the hydrophobic functional groups in LB-EPS provided more binding sites during the flocculation process and formed a network structure of microalgal cells-flocculants-nanosilica. The resulting larger and more stable biomimetic silica shell promoted microalgal flocculation and sedimentation. Compared to conventional harvesting methods (centrifugation, polyacrylamide, alkaline flocculation), this method had the minimal negative impact on harvested biomass, with 9.95% of cell membranes damaged.
研究领域:
环境科学
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生物技术
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微生物学
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化学工程
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产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY
·
2024
·
IF 5
Gang Wang,Jia Kong,Tuo Leng,Weidong Zhang,Ting Chen,Xizhe Xu,Zhibing Huang,Jianhua Xie
Penicillium exopolysaccharide (EPS) inhibits galactose lectins and enhances immunity. However, EPS production is low and its synthesis mechanism remains unclear. Penicillium EF-2 strains with high EPS production were selected for this study, and Penicillium fermentation conditions were subsequently improved. The optimal culture conditions were 30 g/L lactose, 6 g/L yeast extract powder, 4 d seed age, 10 % inoculation amount, 3 d of secondary fermentation time, and the final EPS yield was 3.97 g/L. UHPLC-Q-TOF-MS/MS was used to explore the mechanism of EPS synthesis at the metabolic level. Optimal carbon source: lactose and optimal nitrogen source: yeast extract can provide precursors for EPS synthesis through related metabolic pathways. Moreover, regulating the energy, vitamin, and lipid metabolic pathways created favourable conditions for EPS synthesis and secretion. These findings explain the mechanism of EPS synthesis at the metabolic level and provide a theoretical basis for optimising and industrialising EPS production.
研究领域:
微生物学
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生物技术
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代谢组学
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生物化学
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产品关联
DOI
PubMed
高影响因子
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
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2022
·
IF 7.129
Wenjie Xu,Ziyi Yang,Hao Tang,Chen Wang,Zhengfang Ye
Tetracycline (TC) as one of the most widely used antibiotics commonly exists in aquaculture tail water and piggery wastewater, causing risks to human. However, the response of immobilized anaerobic denitrifying bacterial consortium to TC exposure lacks systematic research. In this study, the denitrification performance and the compositional shift of extracellular polymeric substances (EPS) and microbial community under TC stress were investigated. The inhabitation effect of TC on nitrate reduction of the immobilized bacterial consortium became evident at high concentrations (50 mg/L and 100 mg/L). Nitrite reduction was more sensitively inhibited than nitrate reduction. The inhabitation effect was mainly due to the fact that TC damaged cell membranes and subsequently effect the intracellular enzymes activities relating to denitrification (NAR and NIR activities). About 50% of TC can be removed by the immobilized bacterial consortium under all tested TC concentrations. Three-dimensional excitation-emission matrix (3D-EEM) results implied that the tryptophan like substances of EPS were obviously quenched with increasing TC concentration. EPS played an important role in TC removal. The denitification performance of the immobilized bacterial consortium under TC stress was attributed to the genera Paraccoccus , Pseudoxanthomonas , Diaphorobacter and Pseudomonas . Initial TC concentration obviously affected the microbial communities. This study may facilitate the management of aquaculture tail water and piggery wastewater contaminated with nitrate and antibiotics.
研究领域:
环境科学
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微生物学
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水处理
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废水管理
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DOI
PubMed
高影响因子
JOURNAL OF ETHNOPHARMACOLOGY
·
2021
·
IF 4.36
Junyu Tao,Shilun Yan,Chuyue Zhou,Qiong Liu,Hui Zhu,Zhen Wen
Ethanopharmacological relevance Potentilla kleiniana Wight et Arn is a wide-spread wild plant in the mountainous areas in southern China. The whole herb has been used as a traditional herbal medicine to treat fever, arthritis , malaria, insect and snake bites , hepatitis, and traumatic injury. In vitro studies have reported the antibacterial activity use of the plant in traditional medicinal systems. Aim of the study The aim of this study was to investigate the inhibitory activity of total flavonoid from Potentilla kleiniana Wight et Arn (TFP) on methicillin-resistant Staphylococcus aureus (MRSA) in planktonic state and biofilm state. Materials and methods Antibacterial activities of TFP on planktonic MRSA were determined by agar diffusion method, microtiter plate assay and time-kill curve assay. Electrical conductivity, membrane permeability, membrane potential and autoaggregation were analyzed to study TFP effects on planktonic MRSA growth. Crystal violet (CV) staining and confocal laser scanning microscopy (CLSM) were analyzed to study TFP effects on aggregation and maturation of MRSA biofilm. After TFP treatment, extracellular polymeric substances (EPS) production were examined. Morphological changes in planktonic and MRSA biofilm following TFP treatment were determined with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, α-Toxin protein expression and adhesion-related gene expression were also determined. Results The minimum inhibitory concentration (MIC) of TFP against MRSA was 20 μg/mL. The agar diffusion method and time-kill curve assay results indicated that TFP inhibited planktonic MRSA growth. TFP treatment significantly inhibited planktonic MRSA growth by inhibiting autoaggregation, α-hemolysin activity, α-Toxin protein expression, but increasing electrolyte leakage, membrane permeability and membrane potential and impacting cell structure. Moreover, TFP treatment significantly inhibited aggregation and maturation on MRSA biofilm by decreasing surface hydrophobicity , EPS production and adhesion-related gene expression. Conclusion The results of this trial provide scientific experimental data on the traditional use of Potentilla Kleiniana Wight et Arn for traumatic injury treatment and further demonstrate the potential of TFP to be developed as a novel anti-biofilm drug.
研究领域:
药理学
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微生物学
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民族药理学
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植物科学
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产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Hanqi Wu,Weizheng Zhang,Xuhui Huang,Peng Gu,Qi Li,Xingzhang Luo,Zheng Zheng
Perfluorooctanoic acid (PFOA), a widespread and emerging organic contaminant of aquatic environments, has high bioaccumulation potential and high toxicity. Consequently, major concerns have been raised worldwide regarding the management of this pollutant in aquatic ecosystems. To thoroughly understand PFOA's toxic effects on aquatic organisms, systematic investigations were conducted on the cellular responses of Microcystis aeruginosa to the environmental concentrations of PFOA under various concentrations as well as phosphorus (P) conditions (concentrations and forms). The results showed that P conditions remarkably affected cyanobacterial growth as well as photosynthetic pigment content, triggered oxidative stress to disrupt the function and structure of the cell membrane, and caused changes in the extracellular and intracellular contents of microcystin-LR (MC-LR). Furthermore, PFOA (100 μg/L) was absorbed by cyanobacterial cells through the stimulation of the secretion of extracellular polymeric substances (EPS) by M. aeruginosa . After entering the cyanobacterial cells, PFOA inhibited photosynthesis, reduced P absorption, induced oxidative damage, lead to a loss of cell integrity evident in scanning electron microscope images, and increased mcy A gene expression to promote MC-LR production. Moreover, the limited P concentration and forms conditions led to increased PFOA absorption by cyanobacterial cells, which further upregulated mcy A gene expression and increased the risk of MC-LR diffusion into the aquatic environment. Our present study provided a theoretical basis and new ideas for understanding and addressing safety issues related to the presence of PFOA in aquatic environments with varying nutritional statuses.
研究领域:
环境科学
·
水生毒理学
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生态毒理学
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微生物学
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分子生物学
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产品关联
DOI
PubMed
高影响因子
Nano Today
·
2024
·
IF 13.2
Fanqiang Bu,Mengnan Liu,Wangtao Zhao,Fang Liu,Wensheng Xie,Guofeng Li,Xing Wang
Combating bacterial biofilm poses a significant challenge because of the dense extracellular polymeric substance (EPS) barrier and inherent drug tolerance. Herein, the designed core-shell nanoparticles (DA 3 -NPs) that eradicate biofilm by precise in-situ phototherapy are reported. DA 3 -NPs are self-assembled using thermosensitive azo-polymers (AP 3 ) to encapsulate GSH-degradable phototherapeutic polymers (DBP) via charge interaction. Notably, D -aminoalanine grafted onto the AP 3 serves as a critical component, providing an electroneutral shell and bacterial peptidoglycan targeting ability to the DA 3 -NPs. Consequently, DA 3 -NPs effectively penetrate EPS up to a depth of 60 µm and precisely target the bacteria within the biofilms. Upon exposure to laser irradiation and the GSH microenvironment, DA 3 -NPs undergo sequential responses involving shell detachment and core disintegration. These processes facilitate point-to-point bacterial killing through the in-situ generations of ROS, carbon radicals and heat damage to the internal bacteria. Compared to non-targeted nanoparticles, DA 3 -NPs exhibit a 61-fold increase in biofilm removal efficiency. This study thus presents a precise in-situ phototherapy strategy for nonantibiotic treatment of biofilm infections.
研究领域:
纳米技术
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生物医学工程
·
微生物学
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药学
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DOI
高影响因子
PHYTOPATHOLOGY
·
2020
·Vol. 110
·期 5
·
IF 3.234
Ping Yang,Fang-Jing Li,Shi-Wen Huang,Man Luo,Wei Lin,Gao-Qing Yuan,Qi-Qin Li
Berberine, a botanical drug, has great ability to inhibit the growth of Xanthomonas oryzae pv. oryzae . However, the antibacterial mechanism of berberine against X. oryzae pv. oryzae remains poorly understood. In this study, we investigated the physiological and transcriptional response of X. oryzae pv. oryzae to berberine. When strain X. oryzae pv. oryzae GX13 was treated with berberine (10 µg/ml), the hypersensitive response in tobacco, virulence to rice, pathogen population in the rice xylem, production of extracellular polysaccharide (EPS), and activity of extracellular hydrolases decreased, but the levels of pyruvate and ATP increased. Moreover, biofilm formation was inhibited, and the cell membrane was damaged. Transcriptome sequencing analysis showed downregulated expression of gspD , gspE , and gspF , involved in the type II secretion system (T2SS); hrcC , hrcJ , hrcN , and others, involved in the type III secretion system (T3SS); gumB and gumC , associated with EPS; zapE , ftsQ , and zapA , associated with cell division; lpxH , lpxK , kdtA , and others, associated with the membrane; and pyk , pgk , and mdh , encoding pyruvate kinase, phosphoglycerate kinase, and malate dehydrogenase, respectively. Upregulated expression was observed for nuoA , nuoB , and nuoH , encoding the NADH dehydrogenase complex, and atpF , atpC , and atpB , encoding ATP synthase. An adenylate cyclase ( CyaA ) fusion assay showed that berberine affects type three effector protein secretion via the T3SS and reduces effector translocation in X. oryzae pv. oryzae . It is speculated that the negative growth and virulence phenotypes of berberine-treated X. oryzae pv. oryzae GX13 may involve differentially expressed genes associated with cytoarchitecture and energy metabolism, and these effects on primary cell function may further dampen virulence and result in differential expression of T3SS- and T2SS-related genes.
研究领域:
植物病理学
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微生物学
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分子生物学
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药理学
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DOI
PubMed
高影响因子
Theranostics
·
2020
·
IF 8.579
Chaoli Wang,Peng Chen,Youbei Qiao,Yuan Kang,Chaoren Yan,Zhe Yu,Jian Wang,Xin He,Hong Wu
Background : Biofilm infection caused by multidrug-resistant bacteria is difficult to eradicate by conventional therapies. Photodynamic therapy (PDT) is an effective antibacterial method for fighting against biofilm infection. However, the blocked photosensitizers outside of biofilm greatly limit the efficacy of PDT. Methods : Herein, a novel acid-responsive superporogen and photosensitizer (SiO 2 -P Ce6-IL ) was developed. Because of the protonation of the photosensitizer and the high binding energy of the polyionic liquid, SiO 2 -P Ce6-IL changed to positive SiO 2 -P IL + in an acidic microenvironment of biofilm infection. SiO 2 -P IL + could combine with negatively charged extracellular polymeric substances (EPS) and create holes to remove the biofilm barrier. To strengthen the interaction between SiO 2 -P IL + and EPS, SiO 2 -P IL + of high charge density was prepared by grafting the high-density initiation site of ATRP onto the surface of the SiO 2 base. Results : Due to the rapid protonation rate of COO - and the strong binding energy of SiO 2 -P IL + with EPS, SiO 2 -P Ce6-IL could release 90% of Ce6 in 10 s. With the stronger electrostatic and hydrophobic interaction of SiO 2 -P IL + with EPS, the surface potential, hydrophobicity, adhesion and mechanical strength of biofilm were changed, and holes in the biofilm were created in 10 min. Combining with the release of photosensitizers and the porous structure of the biofilm, Ce6 was efficiently concentrated in the biofilm. The in vitro and in vivo antibacterial experiments proved that SiO 2 -P Ce6-IL dramatically improved the PDT efficacy against MRSA biofilm infection. Conclusion : These findings suggest that SiO 2 -P Ce6-IL could rapidly increase the concentration of photosensitizer in biofilm and it is an effective therapy for combating biofilm infection.
研究领域:
材料科学
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纳米技术
·
生物医学工程
·
微生物学
·
药学
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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）