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铁锰氧化物提高巴斯德梭菌电子输出率 总被引:1,自引:0,他引:1
[背景]发酵型异化金属还原菌通过发酵获取能量,同时也具有一定的异化还原变价金属氧化物的能力,关于变价金属氧化物对发酵型异化金属还原菌电子输出率的影响还知之甚少。[目的]探究铁锰氧化物(Fe2O3/MnO2)对发酵型异化金属还原菌Clostridium pasteurianum电子输出率的影响。[方法]将不同浓度Fe2O3/MnO2添加到以葡萄糖为底物并接种5%C.pasteurianum的发酵体系中,利用电化学工作站检测C.pasteurianum电化学特性;以菲啰嗪(Ferrozine)显色法和甲醛肟法分别测定发酵体系中Fe(Ⅱ)、Mn(Ⅱ)含量;气相色谱、高效液相色谱检测发酵底物葡萄糖及代谢产物(乙酸、丁酸、CO2和H2)随发酵时间的变化情况;最后计算发酵过程的电子输出率。[结果]研究表明,接种C.pasteurianum的微生物燃料电池可以检测到电流的产生,最大电流密度为0.93 mA/m^2;随着发酵时间的推移,反应体系中Fe(Ⅱ)和Mn(Ⅱ)的浓度逐渐增高;Fe2O3/MnO2的添加使发酵体系中葡萄糖消耗量提高了9.4%/7.7%,同时,乙酸产量提高了37.5%/25.0%,丁酸产量提高了22.7%/6.8%,氢气产量提高了21.6%/9.8%,而总的电子输出率则提高了24.27%/10.82%;添加铁锰氧化物的实验组pH值与对照组相比无显著差异。[结论]铁锰氧化物的添加可以提高C.pasteurianum的电子输出率,其原因可能是增加了葡萄糖消耗和缓冲pH值。研究结果为揭示变价金属氧化物影响发酵型异化金属还原菌电子输出的规律提供了证据,并进一步拓展了对变价金属氧化物与发酵型异化金属还原菌之间相互作用机制的认识。 相似文献
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Fe(Ⅲ)的微生物异化还原 总被引:7,自引:0,他引:7
异化Fe(Ⅲ)还原微生物是厌氧环境中广泛存在的一类主要微生物类群,它们的共同特征是可以利用Fe(Ⅲ)作为末端电子受体而获能。异化Fe(Ⅲ)还原微生物具有强大的代谢功能,可还原许多有毒重金属包括一些放射性核素,还可降解利用许多有机污染物,在污染环境的生物修复中具有重要的应用价值。本文对异化Fe(Ⅲ)还原微生物的分布、分类,代谢功能多样性以及异化Fe(Ⅲ)还原的意义做了评述,旨在加强相关领域的研究人员对此的了解和重视,通过学科的交叉和合作加快我国在这一领域的研究。 相似文献
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铁还原菌是一种典型的异化金属还原菌,广泛分布于海洋沉积物、陆地深地层等自然环境,该类细菌可以将铁氧化物中的Fe(Ⅲ)还原为Fe(Ⅱ),在铁、碳的生物地球化学铁循环中发挥重要作用。铁还原菌的末端电子不局限于Fe(Ⅲ),还可以是其他高价金属、有机污染物,可用于土壤、地下水的污染修复和毒性削减。在微生物电化学系统中,铁还原菌氧化有机物产生的电子直接传递给电极,可以产生电能。基于这种独特的胞外电子传递方式,衍生出了微生物燃料电池、微生物电解池、微生物脱盐电池、微生物燃料电池耦合芬顿反应以及光催化微生物燃料电池,常用于微生物发电、生物传感器、生物制氢、定向发酵、海水淡化、生物脱盐和污染物分解矿化。本文从异化铁还原菌的代谢机制、微生态作用、环境修复、水资源再生与能源转化四个方面,综述了铁还原菌的作用原理及国内外研究现状,分析论述了目前亟需解决的关键问题和未来的研究方向,以期为铁还原菌的基础理论研究和应用技术研发提供参考。 相似文献
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异化Fe(Ⅲ)还原微生物研究进展 总被引:7,自引:0,他引:7
铁是地壳中含量第四丰富的元素,微生物介导的异化铁还原是自然界中Fe(Ⅲ)还原的主要途径。介绍了Fe(Ⅲ)还原菌的分类及多样性,总结了Fe(Ⅲ)还原菌还原铁氧化物机制及其产能代谢机制,概述了Fe(Ⅲ)还原菌的生态环境意义,并对未来Fe(Ⅲ)还原菌的分子生态学研究方向提出了探索性的建议。 相似文献
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微生物对硒的还原及其产物的应用研究进展——纪念硒发现200周年 总被引:1,自引:0,他引:1
硒是生命必需的微量元素,以硒代半胱氨酸(Sec,第21位氨基酸)和硒代甲硫氨酸(Se-Met)的形式加入到硒蛋白(酶)中。人畜硒摄入过量或不足均会导致很多疾病。微生物参与了Se(-Ⅱ)、Se(0)、Se(Ⅳ)和Se(Ⅵ)等各种价态间的转化。本文主要综述微生物对硒的还原及其生物学意义。微生物对硒的还原包括同化还原、异化还原以及在还原基础上进行的硒的甲基化。硒的同化还原主要是形成各种硒蛋白,满足微生物自身对硒的需求,食源性微生物对人畜补硒具有重要意义。高浓度硒酸盐和亚硒酸盐则可促使微生物进行异化还原并形成单质纳米硒颗粒。有的微生物会将还原态的Sec和Se-Met进一步转化为挥发态的甲基化硒。硒的异化还原和甲基化都是解毒机制,在硒污染环境的治理中具有重要意义。最后,阐述了单质纳米硒在医药、生物传感器和治理重金属污染等方面的应用前景,以及微生物合成CdSe荧光量子点的应用。 相似文献
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Aeromonas hydrophila ATCC 7966 grew anaerobically on glycerol with nitrate, fumarate, Fe(III), Co(III), or Se(VI) as the sole terminal electron
acceptor, but did not ferment glycerol. Final cell yields were directly proportional to the amount of terminal electron acceptor
provided. Twenty-four estuarine mesophilic aeromonads were isolated; all reduced nitrate, Fe(III), or Co(III), and five strains
reduced Se(VI). Dissimilatory Fe(III) reduction by A. hydrophila may involve cytochromes. Difference spectra obtained with whole cells showed absorption maxima at wavelengths characteristic
of c-type cytochromes (419, 522, and 553 nm). Hydrogen-reduced cytochromes within intact cells were oxidized by the addition of
Fe(III) or nitrate. Studies with respiratory inhibitors yielded results consistent with a respiratory chain involving succinate
(flavin-containing) dehydrogenase, quinones and cytochromes, and a single Fe(III) reductase. Neither anaerobic respiration
nor dissimilatory metal reduction by members of the genus Aeromonas have been reported previously.
Received: 24 June 1997 / Accepted: 20 October 1997 相似文献
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Microbial Metabolism of Benzene and the Oxidation of Ferrous Iron under Anaerobic Conditions: Implications for Bioremediation 总被引:1,自引:0,他引:1
Benzene and toluene were biodegraded when chelated Fe(III) served as the terminal electron acceptor in aquifer sediments contaminated by a petroleum refinery. Benzene biodegradation ceased when Fe(III) was depleted but resumed upon reamendment. Microorganisms from the same sediments degraded toluene, but not benzene, under nitrate reducing conditions. However, the anaerobic oxidation of Fe(II) to Fe(III) was also observed in toluene-degrading incubations. Fe(II) oxidation was dependent on the presence of nitrate and enhanced when organic electron donors were provided. Microbial nitrate-linked Fe(II) oxidation was also documented in other petroleum-contaminated aquifer sediments, sludge from an oil–water separator, a landfill leachate-impacted aquifer and a garden soil. These observations suggest that some of the reported effects of nitrate on hydrocarbon biodegradation may be indirect through the reoxidation of Fe(II). 相似文献
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Geovibrio ferrireducens,a phylogenetically distinct dissimilatory Fe(III)-reducing bacterium 总被引:1,自引:0,他引:1
F. Caccavo Jr. John D. Coates Ramon A. Rossello-Mora Wolfgang Ludwig Karl Heinz Schleifer Derek R. Lovley Michael J. McInerney 《Archives of microbiology》1996,165(6):370-376
A new, phylogenetically distinct, dissimilatory, Fe(III)-reducing bacterium was isolated from surface sediment of a hydrocarbon-contaminated
ditch. The isolate, designated strain PAL-1, was an obligately anaerobic, non-fermentative, motile, gram-negative vibrio.
PAL-1 grew in a defined medium with acetate as electron donor and ferric pyrophosphate, ferric oxyhydroxide, ferric citrate,
Co(III)-EDTA, or elemental sulfur as sole electron acceptor. PAL-1 also used proline, hydrogen, lactate, propionate, succinate,
fumarate, pyruvate, or yeast extract as electron donors for Fe(III) reduction. It is the first bacterium known to couple the
oxidation of an amino acid to Fe(III) reduction. PAl-1 did not reduce oxygen, Mn(IV), U(VI), Cr(VI), nitrate, sulfate, sulfite,
or thiosulfate with acetate as the electron donor. Cell suspensions of PAL-1 exhibited dithionite-reduced minus air-oxidized difference spectra that were characteristic of c-type cytochromes. Analysis of the 16S rRNA gene sequence of PAL-1 showed that the strain is not related to any of the described
metal-reducing bacteria in the Proteobacteria and, together with Flexistipes sinusarabici, forms a separate line of descent within the Bacteria. Phenotypically and phylogenetically, strain PAl-1 differs from all other
described bacteria, and represents the type strain of a new genus and species, Geovibrio
ferrireducens.
Received: 26 September 1995 / Accepted: 28 February 1996 相似文献
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Ultraviolet light sensitive mutants of Coprinus lagopus. I. Isolation and characterization 总被引:2,自引:0,他引:2
4UV-sensitive mutants have been isolated from the wild type strain BC9/66 of Coprinus lagopus by following a new replica plating technique. Complementation and recombination studies between these mutants suggest 3 gene loci uvs1, uvs2 and uvs3, two of the mutants being allelic (uvs3-1 and uvs3-2). The mutants uvs2, uvs3-1 and uvs3-2 show photoreactivation whereas the mutant uvs1 appears to be deficient in this respect. None of the mutants of the wild type showed significant recovery after dark holding. 相似文献
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The reduction of Cr(VI) at the expense of molecular hydrogen was studied using resting cells of Desulfovibrio vulgaris ATCC 29579 in anaerobic resting cell suspensions in MOPS buffer. Bioreduction occurred only in the presence of ligands or chelating agents (CO32-, citrate, NTA, EDTA, DTPA). The stimulatory effect of these ligands on the rate of Cr(VI) reduction was correlated (r = 0.988) with the strength of the ligand/chelate complex of Cr(III). The data are examined with respect to likely solution and redox equilibria in the ionic matrix of the carrier solution, and with respect to the potential for bioremediation of Cr(VI). 相似文献
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Chernyh NA Gavrilov SN Sorokin VV German KE Sergeant C Simonoff M Robb F Slobodkin AI 《Applied microbiology and biotechnology》2007,76(2):467-472
Washed cell suspensions of the anaerobic hyperthermophilic archaea Thermococcus pacificus and Thermoproteus uzoniensis and the anaerobic thermophilic gram-positive bacteria Thermoterrabacterium ferrireducens and Tepidibacter thalassicus reduced technetium [99Tc(VII)], supplied as soluble pertechnetate with molecular hydrogen as an electron donor, forming highly insoluble Tc(IV)-containing
grayish-black precipitate. Apart from molecular hydrogen, T. ferrireducens reduced Tc(VII) with lactate, glycerol, and yeast extract as electron donors, and T. thalassicus reduced it with peptone. Scanning electron microscopy and X-ray microanalysis of cell suspensions of T. ferrireducens showed the presence of Tc-containing particles attached to the surfaces of non-lysed cells. This is the first report on the
reduction in Tc(VII) by thermophilic microorganisms of the domain Bacteria and by archaea of the phylum Euryarchaeota. 相似文献
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Out of nineteen bacteria screened from the tannery waste dump site, the most effective isolate, strain DU17 was selected for Cr(VI) reduction process among the non-pathogenic once. Based on 16S rRNA gene sequence analysis, the bacterium was identified as Enterobacter sp. DU17. Its amplified Cr(VI) reductase gene showed maximum homology with flavoprotein of Enterobacter cloacae. Enterobacter sp. DU17 reduced Cr(VI) maximally at 37 °C and pH 7.0. Various co-metals, electron (e−) donors and inhibitors were tested to study their effect on Cr(VI) reduction. In presence (0.2% each) of glucose and fructose, Enterobacter sp. DU17 reduced Cr(VI) completely after 16 and 20 h, respectively. Since the concentration of total Cr was invariable after remediation as detected through AAS analysis, this experiment disclosed that responsible operation was associated with extracellular Cr(VI) reduction process rather than uptake mechanism. Multiple antibiotic resistance index of 0.08 for this bacterium was very low as compared to standard risk assessment value of 0.20. With high Cr(VI) reducing capability, non-pathogenicity and antibiotic sensitivity, Enterobacter sp. DU17 is found to be very efficient in removing Cr(VI) toxicity from the environment. 相似文献
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D R Lovley 《Journal of industrial microbiology & biotechnology》1997,18(2-3):75-81
Laboratory incubations of aquifer material or enrichments derived from aquifer material as well as geochemical data have
suggested that, under the appropriate conditions, BTEX components of petroleum (benzene, toluene, ethylbenzene and xylene)
can be degraded in the absence of molecular oxygen with either Fe(III), sulfate, or nitrate serving as the electron acceptor.
BTEX degradation under methanogenic conditions has also been observed. However, especially for benzene, the BTEX contaminant
of greatest concern, anaerobic degradation is often difficult to establish and maintain in laboratory incubations. Although
studies to date have suggested that naturally occurring anaerobic BTEX degradation has the potential to remove significant
quantities of BTEX from petroleum-contaminated aquifers, and mechanisms for stimulating anaerobic BTEX degradation in laboratory
incubations have been developed, further study of the organisms involved in this metabolism and the factors controlling their
distribution and activity are required before it will be possible to design rational strategies for accelerating anaerobic
BTEX degradation in contaminated aquifers.
Received 21 November 1995/ Accepted in revised form 20 February 1996 相似文献