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Phenotype and metabolism alterations in PCB-degrading Rhodococcus biphenylivorans TG9^(T) under acid stress

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Journal of environmental Sciences 2023年第5期127卷 441-452页

作者： Aili Li Jiahui Fan Yangyang Jia Xianjin Tang Jingwen Chen Chaofeng Shen Department of environmental engineering College of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058China MOE Key Lab of environmental Remediation and Ecosystem Health College of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058China

environmental acidification impairs microorganism diversity and their functions on substance transformation.Rhodococcus is a ubiquitously distributed genus for contaminant detoxification in the environment,and it can also adapt a certain range of pH.This work interpreted the acid responses from both phenotype and metabolism in strain Rhodococcus biphenylivorans TG9^(T)(TG9)induced at pH 3.The phenotype alterations were described with the number of culturable and viable cells,intracellular ATP concentrations,cell shape and entocyte,degradation efficiency of polychlorinated biphenyl(PCB)31 and biphenyl.The number of culturable cells maintained rather stable within the first 10 days,even though the other phenotypes had noticeable alterations,indicating that TG9 possesses certain capacities to survive under acid stress.The metabolism responses were interpreted based on transcription analyses with four treatments including log phase(LP),acid-induced(PER),early recovery after removing acid(RE)and later recovery(REL).With the overview on the expression regulations among the 4 treatments,the RE sample presented more upregulated and less downregulated genes,suggesting that its metabolism was somehow more active after recovering from acid stress.In addition,the response mechanism was interpreted on 10 individual metabolism pathways mainly covering protein modification,antioxidation,antipermeability,H+consumption,neutralization and extrusion.Furthermore,the transcription variations were verified with RT-qPCR on 8 genes with 24-hr,48-hr and 72-hr acid treatment.Taken together,TG9 possesses comprehensive metabolism strategies defending against acid stress.Consequently,a model was built to provide an integrate insight to understand the acid resistance/tolerance metabolisms in microorganisms.

关键词： environmental acidification Rhodococcus biphenylivorans Contaminant degradation Phenotypic response Transcription analysis Metabolism pathway Mechanism model

Reagent elution combined with positive pressure filtration:A zero-discharge method for cyanide tailings remediation

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Journal of environmental Sciences 2022年第3期34卷 376-384页

作者： Qiang Liu Yating Luo Jiyan Shi Department of environmental engineering College of Environmental and Resource ScienceZhejiang UniversityHangzhou 310058China Changchun Gold Research Institute Co.Ltd Changchun 130012China

At present, the cyanide gold extraction process is still the main technology for gold production. Generated cyanide tailings containing highly toxic substances exhibit potential environmental risks. These tailings are in urgent need of purification treatment, especially after being classified as hazardous waste. In this study, the impacts of elution methods, operating time, tailings/water ratios, reagent types on the elution rates of cyanide were investigated. Furthermore, the composite elution method developed in this research was extended for engineering. Results showed that the optimum elution conditions were determined to be: stirring elution, tailings/water ratio( M/V;1:1) and operating time(10-20 min). Besides, 4 reagents(sodium dodecyl benzene sulfonate, cyclodextrin, sodium silicate and calcium hydroxide) were selected from four categories of 21 reagents for further composite elution. The cyanide elution rate was the highest(90.7% ±0.1%) while the molar ratio of these 4 reagents was 5:2:2:1. Moreover, the combination of reagent elution and positive pressure filtration improved the elution efficiency of cyanide(92.6% ±0.8%). And the cyanide content in the toxic leaching solution was lower than the standard value(5.0 mg/L). Furthermore, the composite elution method developed in this study was also extended for engineering. The concentration of cyanide in the leachate was engineering treatment of cyanide tailings.

关键词： Cyanide tailings Decyanation treatment Remediation engineering

Overestimate of remediation efficiency due to residual sodium persulfate in PAHs contaminated soil and a solution

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Journal of environmental Sciences 2022年第3期34卷 242-250页

作者： Liping He Jianhao Tong Yuanqiang Yang Jianxun Wu Linqian Li Zhonghua Wei Wei Long Jingli Pang Jiyan Shi Yunnan Research Academy of Eco-environmental Sciences Kunming 650034China Department of environmental engineering College of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058China Beijing Construction engineering Group environmental Remediation Co.Ltd. Beijing 100015China

Oxidation remediation is a commonly used technology for PAHs contaminated soil presently,but the overestimate of efficiency due to ongoing remediation by residual oxidants during extraction and testing has not been paid enough attention.In this study,persulfate was activated by Fe(Ⅱ)to investigate the effects of residual oxidants on PAHs removal during detection process and the elimination effects of adding Na_(2)SO_(3) and extending sampling time on residual oxidants.Results verified that the residual oxidants removed PAHs in extraction process,making the results lower than the actual values:the detection recovery rate η of ΣPAHs and 3-6 ring PAHs ranged from 24.3%(25%Na_(2)S_(2)O_(8)treatment)to 87.4%(5%Na_(2)S_(2)O_(8)+4/4Fe^(2+) treatment),20.1%-99.0%,28.9%-87.9%,20.8%-89.4%,and 1.8.6%-76.9%,respectively.After adding Na_(2)SO_(3),the accuracy of detection results increased significantly:the η of ΣPAHs and 3-6 ring PAHs increased to 64.1%-96.5%,58.8%-95.5%,73.8%-114.4%,60.6%-95.6%,and 45.4%-77.1%,respectively.After 49 days of adding oxidants,residual oxidants had no considerable effect on the detection of PAHs,indicating it was appropriate to start soil remediation verification sampling49 days after the remediation was completed.The observed results will help scientific evaluation of the remediation effects of chemical oxidation on or-ganic contaminated soil.

关键词： Persulfate activation Soil remediation Polycyclic aromatic hydrocarbons Residual oxidant removal

Coking wastewater increases micronucleus frequency in mouse in vivo via oxidative stress

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Journal of environmental Sciences 2013年第10期25卷 2123-2129页

作者： Na Zhu Hongyan Li Guangke Li Nan Sang college of Environment and resource Center of Environmental Science and Engineering Shanxi University

Coking wastewater has caused serious health risk in coal-producing areas of China, however its toxic effects have not been well understood. The genotoxicity induced by coking wastewater on mice in vivo and its possible oxidative mechanisms were investigated via observing the induction of micronuclei in polychromatic erythrocytes of mouse bone marrow, and subsequently determining the antioxidative enzyme activities （superoxide dismutase Cu, Zn-SOD, Se-dependent glutathione peroxidase, and catalase）, thiobarbituric acid reactive substance contents and protein carbonyl levels in brains and livers of mice. Results showed that the tested coking wastewater caused a significant increase of micronucleus frequencies in a concentration-dependent manner. Also, the sample increased lipid peroxidation and protein oxidation levels, which was accompanied by changes in antioxidative status. Interestingly, pre-treatment with an antioxidant （vitamin C） led to a statistical reduction in the micronucleus frequency caused by coking wastewater. This implies that coking wastewater induces evident genetic damage in mammalian cells, and exposure to polluted areas might pose a potential genotoxic risk to human beings; in the process, oxidative stress played a crucial role.

关键词： micronucleus oxidative stress coking wastewater mouse bone marrow

Flotation evaluation and adsorption mechanism of medialan collector to wolframite

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Rare Metals 2013年第6期32卷 636-641页

作者： Xian-Ping Luo Li-Ying Luo Li Gao Xue-Kun Tang College of Resource and Environmental Engineering Jiangxi University of Science and Technology

Medialan has preferable flotation performance to wolframite,under the conditions of the best flotation pH value 7.0 and low dosage,wolframite recovery is up to80%.Medialan shows poor flotation performance to quartz,but better to fluorite and calcite.However,fluorite and calcite are inhibited in a certain degree by adding medialan mixed with sodium silicate.Adsorption mechanism of medialan collector on wolfram surface was also studied by using infrared(IR)radiation spectrum,adsorption volume,and zeta potential.The results show that medialan can adsorb on wolfram surface in the form of chemistry adsorption,and as medialan collector dosage changes,change law of adsorption volume is similar with that of wolfram pure mineral flotation.Zeta potential results prove that zeta potential of wolfram surface moves negatively after adsorbing medialan collector.

关键词： Medialan Wolframite Flotation performance IR spectrum measurement Adsorbance Zeta potential

Acetylacetone effectively controlled the secondary metabolites of Microcystis aeruginosa under simulated sunlight irradiation

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Journal of environmental Sciences 2024年第1期135卷 285-295页

作者： Xiaomeng Wang Yixin Luo Shujuan Zhang Lixiang Zhou Department of environmental engineering College of Resources and Environmental SciencesNanjing Agricultural UniversityNanjing 210095China The State Key Laboratory of Pollution Control and resource Reuse School of the EnvironmentNanjing UniversityNanjing 210023China

Inactivation of cyanobacterial cells and simultaneous control of secondary metabolites is of significant necessity for the treatment of cyanobacteria-laden water.Acetylacetone(AcAc)has been reported a specific algicide to inactivate Microcystis aeruginosa(M.aeruginosa)and an effective light activator to degrade pollutants.This study systematically investigated the photodegradation ability of AcAc under xenon(Xe)irradiation on the secondary metabolites of M.aeruginosa,mainly algal organic matter(AOM),especially toxic microcystin-LR(MC-LR).Results showed that AcAc outperformed H_(2)O_(2)in destructing the protein-like substances,humic acid-like matters,aromatic proteins and fulvic-like substances of AOM.For MC-LR(250μg/L),0.05 mmol/L AcAc attained the same degradation efficiency(87.0%)as 0.1mmol/L H_(2)O_(2).The degradation mechanism of Xe/AcAc might involve photo-induced energy/electron transfer and formation of carbon center radicals.Alkaline conditions(pH>9.0)were detrimental to the photoactivity of AcAc,corresponding to the observed degradation rate constant(k_(1)value)of MC-LR drastically decreasing to 0.0013 min^(-1)as solution pH exceeded 9.0.The PO_(4)^(3-)and HCO_(3)^(-)ions had obvious inhibition effects,whereas NO_(3)^(-)slightly improved k_(1)value from 0.0277 min^(-1)to 0.0321 min^(-1).The presence of AOM did not significantly inhibit MC-LR degradation in Xe/AcAc system.In addition,the biological toxicity of MC-LR was greatly reduced after photoreaction.These results demonstrated that AcAc was an alternative algicidal agent to effectively inactivate algal cells and simultaneously control the secondary metabolites after cell lysis.Nevertheless,the concentration and irradiation conditions should be further optimized in practical application.

关键词： Microcystis aeruginosa Photodegradation Acetylacetone Secondary metabolites Microcystin

New insights into the evaluation of anaerobic properties of sludge:Biodegradability and stabilization

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Journal of environmental Sciences 2021年第2期33卷 158-166页

作者： Jun Gao Xiaoyan Zhao Sisi Chen Bin Dong Xiaohu Dai State Key Laboratory of Pollution Control and resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China

Evaluating anaerobic biodegradability of sludge and then identifying the stabilization of digestate is necessary in sludge treatment and disposal.48 sludge samples from 24 typical waste water treatment plants(WWTPs)in 11 provinces in China were selected to investigate the relationship between Biochemical Acidogenic Potential(BAP)test and Biochemical Methane Potential(BMP)test.The volatile fatty acid(VFA)production obtained from BAP tests was found linearly related to the ultimate methane production from corresponding BMP tests.Satisfying results were obtained with Pearson correlation coefficient as 0.929 and R^2 value as 0.76.Furthermore,the physio-chemical characteristics(FCI,SUVA254,E 4/E 6)of supernatant,which were associated with humic-like substances(HS),were investigated before and after BMP tests.Through which a new criterion(FCI>1.50,SUVA 254>1.10,E 4/E 6<4.0)was proposed to evaluate the stabilization level of anaerobic digested sludge.

关键词： Sludge Anaerobic digestion Biodegradability Stabilization Biochemical acidogenic potential Physio-chemical characteristics

Effects of sludge age on anaerobic acidification of waste activated sludge: Volatile fatty acids production and phosphorus release

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Journal of environmental Sciences 2021年第7期33卷 11-21页

作者： Sisi Chen Xiaohu Dai Dianhai Yang Bin Dong State Key Laboratory of Pollution Control and resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China

Effects of sludge age on volatile fatty acids (VFAs) production and Phosphorus (P) release during anaerobic acidification of waste activated sludge (WAS) were investigated.Sequencing batch reactors (SBR) fed with simulating domestic sewage were applied to produce WAS of different sludge ages,and batch tests were used for anaerobic acidification.The maximum dissolved total organic carbon,release of PO_(4)^(3+)-P,and accumulation of acetate (C2),propionate (C3),butyrate (C4),and valerate (C5) decreased by 56.2%,55.8%,52.6%,43.7%,82.4%and 84.8%,respectively,as the sludge age of WAS increased from 5 to 40 days.Limited degradation of protein played a dominating role in decreasing DTOC and VFAs production.Moreover,the increase in molecular weight of organics and organic nitrogen content in the supernatant after acidification suggested that the refractory protein in WAS increased as sludge age extended.Although the production of C2,C3,C4,and C5 from WAS decreased as the sludge age increased,the proportions of C2 and C3 in VFAs increased,which might be due to the declined production of C5 from protein and the faded genus Dechlorobacter.Keeping sludge age of WAS at a relatively low level (resource.

关键词： Sludge age Waste activated sludge Acidification Volatile fatty acids Microbial community

engineering active sites on hierarchical transition bimetal oxyhydride/bicarbonate heterostructure for oxygen evolution catalysis in seawater splitting

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Nano Research 2023年第2期16卷 2094-2101页

作者： Meihong Lin Yang Yang Yunhua Song Donggang Guo Liping Yang Lu Liu Tianjin Key Laboratory of environmental Remediation and Pollution Control College of Environmental Science and EngineeringNankai UniversityTianjin 300350China Shanxi Laboratory for Yellow River College of Environment and ResourceShanxi UniversityTaiyuan 030006China

Designing efficient and stable electrocatalysts to improve the oxygen evolution reaction(OER)with slow reaction kinetics is essential to improve hydrogen production from electrochemical water splitting.This research has prepared a series of FeOOH/Ni(HCO_(3))_(2)heterostructured materials(denoted as FeOOH_(x)/Ni(HCO_(3))_(2))by a one-pot solvothermal method.The OER performance of the catalysts was maximized by finely tuning the content of different components,heterogeneous interfaces,and electronic structures.Specifically,the obtained FeOOH0.60/Ni(HCO_(3))_(2)heterostructured nanosheets had the lowest overpotential of 216 mV at a current density of 10 mA·cm^(−2)and were stable at a high current density of 100 mA·cm^(−2)for more than 96 h.The excellent OER activity and stability were still maintained in alkaline natural seawater(1 M KOH+seawater).When FeOOH0.60/Ni(HCO_(3))_(2)was used as the anode for water splitting,the electrolyzer provided a current density of 10 mA·cm^(−2)at a very low cell voltage of 1.51 V(1.56 V at 1 M KOH+seawater)and exhibited superior stability.The outstanding OER performance is ascribed to the synergistic effect of FeOOH and Ni(HCO_(3))_(2)upon heterostructure formation,as well as the altered electronic structure between the heterogeneous interfaces and the suitable hierarchical nanosheet morphology facilitating many active sites.This work provides a promising direction for improving the electrocatalytic activity of nickel-based catalysts in seawater splitting,which has important implications for both hydrogen economy and environmental remediation.

关键词： synergistic effect heterostructure oxygen evolution reaction iron oxyhydroxide nickel bicarbonate