oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Microbial degradation of 1,2,4-trichlorobenzene: A review
微生物降解1,2,4-三氯苯研究进展

SONG Yang,WANG Fang,JIANG Xin,
宋 洋
,王 芳,蒋 新

土壤 , 2011,
Abstract: The mechanism of microbial degradation of 1,2,4-trichlorobenzene includes aerobic degradation, reductive dechlorination and co-metabolism. This paper provided a brief review of the research progress in the biodegradation of 1,2,4-TCB. The potential biodegradability was analyzed. The pathway of aerobic degradation of 1,2,4-TCB and the related microbial strains, as well as the reductive dechlorination of 1,2,4-TCB by microbial community or single strain were discussed. The aim of this paper is to provide a guide for microbial remediation of 1,2,4-TCB contaminated soil.
Adsorption of Naphthalene on Modified Zeolite from Aqueous Solution  [PDF]
Ning Li, Wang-Yu Cheng, Yong-Zhang Pan
Journal of Environmental Protection (JEP) , 2017, DOI: 10.4236/jep.2017.84030
Abstract: In this study, the modified zeolite with certain hydrophobicity was prepared by modifying natural zeolite by the silane coupling agents such as vinyltrimethoxysilane (VTMO), trimethoxysilane (TMS) and trimethylchlorosilane (TMCS). The modified zeolite has a higher hydrophobicity and adsorption capacity than natural zeolite while ensuring the advantages of natural zeolite, which is more conducive to the adsorption of organic pollutants from aqueous solution. The adsorption experiment on naphthalene in aqueous solution shows that the modified zeolite has a stronger adsorption capacity. In the adsorption thermodynamics experiment, the isothermal adsorption models such as Freundlich and Langmuir can better describe the adsorption of naphthalene on modified zeolite, but the isothermal adsorption model Freundlich has a higher correlation. At 303K, the static adsorption capacity is 339μg/g. The kinetic analysis shows that the adsorption of naphthalene on modified zeolite conforms to the quasi-second order kinetic model.
In silico feasibility of novel biodegradation pathways for 1,2,4-trichlorobenzene
Stacey D Finley, Linda J Broadbelt, Vassily Hatzimanikatis
BMC Systems Biology , 2010, DOI: 10.1186/1752-0509-4-7
Abstract: We have utilized a computational framework called BNICE to generate novel biodegradation routes for 1,2,4-trichlorobenzene (1,2,4-TCB) and incorporated the pathways into a metabolic model for Pseudomonas putida. We studied the cellular feasibility of the pathways by applying metabolic flux analysis (MFA) and thermodynamic constraints. We found that the novel pathways generated by BNICE enabled the cell to produce more biomass than the known pathway. Evaluation of the flux distribution profiles revealed that several properties influenced biomass production: 1) reducing power required, 2) reactions required to generate biomass precursors, 3) oxygen utilization, and 4) thermodynamic topology of the pathway. Based on pathway analysis, MFA, and thermodynamic properties, we identified several promising pathways that can be engineered into a host organism to accomplish bioremediation.This work was aimed at understanding how novel biodegradation pathways influence the existing metabolism of a host organism. We have identified attractive targets for metabolic engineers interested in constructing a microorganism that can be used for bioremediation. Through this work, computational tools are shown to be useful in the design and evaluation of novel xenobiotic biodegradation pathways, identifying cellularly feasible degradation routes.The prevalence and widespread use of man-made chemicals ("xenobiotics") has led to a focused effort to establish new technologies to reduce or eliminate these contaminants from the environment. Commonly used pollution treatment methods such as incineration, landfilling, and air stripping also have an adverse effect on the environment [1,2]. Additionally, these methods are costly and sometimes inefficient. Therefore, it is important to develop alternative methods of biodegradation that are effective, minimally hazardous, and economical. One promising treatment method is to exploit the ability of microorganisms to use these foreign substances for mai
Identification of 1,2,4-Trichlorobenzene-Mineralizing Bacteria and Their Function Analysis
1,2,4-三氯苯矿化菌的鉴定与功能分析

U Drfler,M Schmid,S Grundmann,JC Munch,R Schroll,WANG Fang,U Drfler,M Schmid,S Grundmann,JC Munch,JIANG Xin,R Schroll,
王芳
,U.Drfler,M.Schmi,S.Grundmann,J.C.Munch,蒋新,R.Schroll

环境科学 , 2007,
Abstract: Two strains, E3 and F2, capable to mineralize 1,2,4-trichlorobenzene(1,2,4-TCB) were isolated from a chlorinated benzenes contaminated soil using 14C-1,2,4-TCB as carbon source. They were identified by their 16S rDNA coding genes and fluoresence in situ hybridization (FISH) analysis as members of the genus Bordetella. A similarity of 100% were observed between strains E3 and F2 with their 16S rDNA sequences. They had the highest homology of 100% with Bordetella sp. QJ2-5 and the closest relation to described species, Bordetella petrii (GDH030510) with a similary of 99.4%. Strains E3 and F2 could degrade about 90% of 1,2,4-TCB and mineralize 58% and 46% of 1,2,4-TCB to CO2 within 30 days in mineral liquid cultures, respectively. Biomass was formed during the mineralization process.
Effects of 1,2,4-trichlorobenzene on the mitosis in root meristematic cells of A.sativum seedlings
1,2,4三氯苯对大蒜根尖分生细胞有丝分裂的影响

DU Qingping,JIA Xiaoshan,
杜青平
,贾晓珊

环境科学学报 , 2006,
Abstract: The damage effects of 1,2,4-trichlorobenzene on the mitosis in root meristematic cells of A. sativum seedlings were studied. The results showed the mitotic index in root meristematic cells of A. sativum seedlings were decreased in treated time-response and dose-response manners. The prophase cell ratios among the mitotic cells were relatively increased, while the metaphase, anaphase and telaphase cells ratios were decreased; Compared with anaphase and telophase cells, the decreasing amplitude of metaphase cells was bigger. Compared to the control groups, the frequencies of micronuclei in 1,2,4-trichlorobenzene groups showed no statistic difference, whereas the frequencies of binucleated cells showed distinguished statistic difference (p< 0.01). The increasing of frequency of binucleated cells was dependent on treated time and concentrations. Conclusion: The mitosis in root meristematic cells of A. sativum seedlings were obviously changed after the treatment of 1,2,4-trichlorobenzene, and the abnormal division were increased.
Adsorption Characterization of Strontium on PAN/Zeolite Composite Adsorbent  [PDF]
Sabriye Yusan, Sema Erenturk
World Journal of Nuclear Science and Technology (WJNST) , 2011, DOI: 10.4236/wjnst.2011.11002
Abstract: This work reports the adsorption of strontium from aqueous solutions onto PAN/zeolite composite. The strontium adsorption on the composite adsorbent was studied as a function of initial strontium concentration, pH of the solution, contact time and temperature. Adsorption isotherms like Langmuir, Freundlich,Dubinin–Radushkevich (D–R) and Temkin were used to analyze the equilibrium data at the different concentrations.Adsorption process well fitted to Temkin isotherm model. Thermodynamic parameters such as the changes in enthalpy, entropy and Gibbs’ free energy were determined, showing adsorption to be an exothermic and spontaneous process.
Study of sulfur dioxide adsorption on Y zeolite
IOAN-CEZAR MARCU,IOAN SANDULESCU
Journal of the Serbian Chemical Society , 2004,
Abstract: Sulfur dioxide adsorptive properties of Y zeolite, the structure of which was confirmed by XRD, were investigated at temperatures within the 25 200 oC range and sulfur dioxide concentrations between 0.9 to 6 % (vol./vol.). It was found that this sorbent possesses a relatively high adsorption capacity. The Y zeolite did not lose its activity during 20 adsorption-desorption-regeneration cycles. The manner in which sulfur dioxide is adsorbed on Y type zeolite was also investigated by analyzing the sample with and without adsorbed SO2, using IR spectroscopy, as well as total and Lewis acidity measurements. The sulfur dioxide molecule is probably adsorbed by hydrogen bonding to one or two conveniently positioned surface hydroxyl groups.
Toxic effects of 1,2,4-trichlorobenzene on rice seed germination and seedling growth
1,2,4-三氯苯对水稻种子萌发及幼苗生长的毒性机理

DU Qingping,JIA Xiaoshan,YUAN Baohong,
杜青平
,贾晓珊,袁保红

应用生态学报 , 2006,
Abstract: By the method of water culture, this paper studied the effects of 1,2,4-trichlorobenzene (1,2,4-TCB) on the seed germination and seedling growth of rice, with the chlorophyll, protein and proline contents and cytomembrane permeability of seedling leaf measured. The results showed the seed germination rate and vigor index were decreased with increasing concentration of 1,2,4-TCB, showing a definite dose-response relationship, and the seedling growth and root length were inhibited, showing definite time-response and dose-response relationships. The chlorophyll a, chlorophyll b, total chlorophyll, and protein contents in seedling leaf decreased with increasing concentration of 1,2,4-TCB, while the free proline content and cytomembrane permeability had a sharp increase when the concentration of 1,2,4-TCB was higher than 15 mg x L(-1). All of these suggested that the damage of rice seedling was a complicated process, which might be related to the structural and functional damage of cellular membrane, protein, and organelles.
Adsorption of Xe in zeolite MCM-22

CHEN Fang,DENG Feng,CHENG Mojie,YUE Yong,YE Chaohui,

科学通报(英文版) , 2002,
Abstract: Adsorption of xenon in zeolite MCM-22, a zeo lite containing two separate pore systems, has been investigated in detail by variable temperature (VT) 129Xe NMR spectroscopy. NMR results suggest that Xe atoms are preferentially adsorbed in the supercages of the zeolite at low Xe pressure (less than a few atmosphere), while Xe atoms can penetrate into the two-dimensional sinusoidal channels at high Xe pressure. Exchange of xenon at the different adsorption sites in the same supercage, i.e. xenon atoms in the two pockets and those in the central part of the supercage, was confirmed at 145 K by two-dimensional (2D) 129Xe NMR exchange spectroscopy. The time scale for the exchange is about several milliseconds.
Cloning and Sequence Analysis of 1,2,4-Trichlorobenzene Dioxygenase and Dehydrogenase Genes
1,2,4-三氯苯双加氧酶和脱氢酶基因克隆与序列分析

JIANG Jian,WANG Hui,GAO Jing-si,SONG Lei,NING Da-liang,
姜健
,王慧,高静思,宋蕾,宁大亮

环境科学 , 2008,
Abstract: Pseudomonas nitroreducens J5-1 is able to use monochlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene and 1,2,4-trichlorobenzene as sole carbon and energy sources, and it differs from those 1,2,4-trichlorobenzene degrading bacteria reported in substrate utilizing characters. PCR technique was used to amplify the genes of chlorobenzene dioxygenase and dehydrogenase of J5-1, and they were named as tcbA and tcbB, respectively. Homology analysis indicated that these genes and gene products were most closely related to those of Burkholderia sp. PS12. By alignment of the amino acid sequences of the a subunits of TcbAa (from J5-1) and TecA1 (from PS12), four amino acid residues from site 307 to site 310 were found to be different (I307L, M308T, I309V, Q310E), which probably retarded the preference for the substrate 1,2,4,5-tetrachlorobenzene. Furthermore, the phylogenetic analysis of the dioxygenase alpha subunits showed that TcbAa was belong to the toluene/diphenyl subfamily, and was most closely related to the poly-chlorinated benzene dioxygenase alpha subunit.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.