共查询到20条相似文献,搜索用时 250 毫秒
1.
微生物锑还原成矿有助于降低土壤锑的生物有效性和移动性,是土壤锑污染修复的重要策略之一。电子穿梭体AQDS能够加速土壤富集菌群锑还原速率,可能与其促进微生物呼吸及细胞生长有关。理解电子穿梭体(ES)介导微生物锑还原过程与机制可为土壤锑污染控制提供关键理论支撑。醌类和黄素类电子穿梭体(AQDS和FMN)存在时可能改变微生物呼吸代谢中的电子传递过程,然而ES介导下的微生物锑还原过程及转录响应机制尚不清楚。利用锑污染稻田土壤分离的兼性厌氧锑还原细菌Mesobacillus jeotgali PS1作为研究对象,探究醌类和黄素类电子穿梭体(AQDS和FMN)对菌株PS1锑还原过程及关键功能基因转录活性的影响。结果表明,菌株PS1驱动Sb(Ⅴ)还原为Sb(Ⅲ)过程中水溶态Sb(Ⅲ)随培养时间先累积后下降,培养72 h后水溶态锑去除率为64%,生成十四面体方锑矿,表明菌株PS1驱动锑还原成矿有助于锑的钝化。两种ES能够加速细菌锑还原反应,而对胞外生成的方锑矿晶型没有影响。通过定量分析菌株PS1潜在功能基因转录表达活性,结果表明AQDS相比FMN更能促进菌株PS1细胞膜二甲基亚砜还原酶(DMSOR)基... 相似文献
2.
自然环境中,大多数氯代有机污染物厌氧还原脱氯反应是与土壤环境中一些生源要素的生物化学还原过程相伴生。有机污染物的种类、生物有效性以及毒性能够显著影响这些生源要素的转化,反过来,土壤中活跃的氧化还原反应也可以显著影响有机污染物的动力学转化过程。本文从氧化还原顺序上综述了反硝化过程、铁还原过程、硫酸盐还原过程和产甲烷过程对氯代有机污染物厌氧还原脱氯过程的影响与作用机制,旨在为氯代有机污染物在厌氧环境中还原脱氯的过程与机理的进一步研究、以及还原脱氯与微生物介导的生源要素氧化还原过程的耦合作用机制的揭示提供参考。 相似文献
3.
水稻土中铁的厌氧生物氧化还原循环对砷的影响(The Effect of Anaerobic Redox Cycling of Iron on Arsenic Mobility in Paddy) 总被引:3,自引:0,他引:3
应用砷污染水稻土的厌氧富集培养,探讨水稻土中潜在存在铁厌氧生物循环及其对氮和砷的耦合作用.富集培养直接证明了水稻土中铁的厌氧生物循环:三价铁(人工合成针铁矿)在厌氧条件下被逐渐还原成二价铁;铁还原过程结束并外源添加硝酸根时,培养基中新生的二价铁在依赖于硝酸根的铁氧化菌的作用下被氧化;当提供新的电子供体乙酸时,生物合成的铁矿重新被还原.在铁氧化还原循环过程中,随着铁的还原,培养基中砷的浓度不断增加,反之,当铁逐渐氧化的同时不断地吸附固定培养基中的砷.在铁的厌氧氧化阶段,铁氧化的同时硝酸根被还原,培养基中积累了NH4+和NO2-.因此,厌氧水稻土中可以进行完整的铁氧化还原循环,同时这个循环过程耦合了氮和砷的迁移转化. 相似文献
4.
《应用与环境生物学报》2020,(4)
甲烷是仅次于二氧化碳的重要温室气体.微生物介导的厌氧甲烷氧化(anaerobic oxidation of methane,AOM)是厌氧环境甲烷减排的重要途径,对缓解全球温室效应具有重要意义.AOM既可耦合硫酸盐、硝酸盐、亚硝酸盐等可溶性电子受体的还原,又能耦合金属氧化物等不溶性固体的还原.本文系统综述了金属还原型甲烷厌氧氧化(metal iondependent anaerobic oxidation of methane,M-AOM)的发现、所涉及微生物及其代谢途径、电子传递过程、环境影响因素等.AOM产生的电子可通过细胞直接接触、微生物纳米导线、金属螯合物、氧化还原电子穿梭体4种途径传递至金属离子或氧化物.微生物介导的金属还原,既包括厌氧甲烷营养古菌(anaerobic methanotrophic archaea,ANME)单独负责M-AOM的整个过程;又包括微生物的互营合作,即首先ANME氧化甲烷,并将产生的电子直接传递至互营微生物,接受ANME的电子来还原金属氧化物.鉴于目前没有成功分离出ANME的单一菌株,未来对M-AOM的研究重点将集中在深入解析M-AOM电子传递机制及其生态分布和对甲烷汇的全球贡献上.(图5表1参129) 相似文献
5.
胞外呼吸菌广泛分布于自然生境中,是驱动铁等元素地球化学循环的重要因素,已成为各种有机污染物降解和重金属污染去除的研究热点.为了挖掘具有环境修复应用前景的胞外呼吸菌,从鄱阳湖湿地土壤中筛选具有胞外异化铁还原能力的菌株,通过形态、生理生化和遗传分析进行菌种鉴定,并对其最优生长条件、异化铁还原特性及胞外电子传递机制进行研究.结果显示,分离得到的菌株PY14具有较高的异化铁还原能力,细菌形态、生理生化特征及16S rRNA基因系统发育分析鉴定其为革兰氏阳性的微小杆菌属(Exiguobacterium);具有嗜碱耐盐生长特性,最适生长pH值为8.0,在NaCl浓度高达50g/L条件下生长良好;能够利用葡萄糖、丙酮酸、乙酸和乳酸等多种小分子碳源(电子供体)进行厌氧呼吸,5 d内5 mmol/L水铁矿的还原率高达80%,添加电子穿梭(蒽醌-2,6-二磺酸盐)可显著增强其异化还原水铁矿、针铁矿和赤铁矿的速率;可通过自身分泌腐殖酸类电子穿梭体实现介导异化铁还原过程.本研究获得了一株有望在盐碱土壤或水体等环境中高效驱动铁还原的胞外呼吸菌,为进一步认识革兰氏阳性细菌胞外电子传递机制提供新依据.(图8表1参4... 相似文献
6.
铁氨氧化(Feammox)是一种以廉价、易得的铁作为微生物电子供体的新型自养生物脱氮技术,即Fe(Ⅲ)还原与厌氧氨氧化的结合工艺,拥有成本低廉、无需有机碳源、污泥产量小、无温室气体产生等优势,是污水处理的一种潜在脱氮途径.本文对铁氨氧化反应的机理、功能菌种的种类和特性及电子穿梭体对其的影响进行了介绍,总结了铁氨氧化在污水环境中的脱氮效果及其与厌氧氨氧化、硝酸盐依赖型亚铁氧化和生物电化学系统的耦合技术,并指出目前铁氨氧化的应用问题及该技术未来的研究方向和重点可能是菌分离纯化、工艺参数控制. 相似文献
7.
多氯联苯是一种典型的持久性有机污染物,其在环境中的转化归趋备受关注.在厌氧条件下,多氯联苯可以通过微生物脱氯进行降解,该降解方式虽然广泛存在于自然界中,但是受生物地球化学因素的影响较大,调控较为复杂.本文对多氯联苯的厌氧微生物脱氯降解进行综述,讨论了脱氯路径和自然界中8种主要脱氯历程;脱氯微生物及相关的微生物还原脱卤酶;影响脱氯速率、程度和历程的主要物理和地球化学因素(温度、pH和氧化还原水平、碳源、电子受体、电子供体及抑制物).最后分析了多氯联苯厌氧脱氯研究中存在的问题并对其前景进行展望. 相似文献
8.
铁还原菌介导的氧化铁还原与硝酸盐还原的竞争效应研究 总被引:1,自引:0,他引:1
中性厌氧条件下,脱色希瓦氏菌Shewanella decolorationis(S12)能够使用多种电子受体进行厌氧呼吸,包括溶解态的硝酸盐以及难溶态的氧化铁基质。因此,本文通过构建"脱色希瓦氏菌/铁氧化物/硝态氮"的交互反应体系,研究这一体系中铁还原与硝态氮还原的相互作用过程,并对相互作用机制进行初步探讨。结果表明,交互反应体系中氧化铁还原与硝酸盐还原存在明显的竞争关系;随着氧化铁比表面积、可利用态铁含量的增大,硝酸受抑制作用逐渐增强;通过不同温度煅烧而得到的不同结晶度的赤铁矿对硝态氮的抑制作用也被研究。结果还表明,氧化铁结晶度越高,S12对硝态氮的还原抑制作用越小。循环伏安电化学测试结果发现,加入硝酸条件下,铁氧化峰几乎完全消失,表明硝态氮存在条件下,铁还原受到明显抑制。针对以上结果,初步探讨了铁还原与硝态氮还原竞争的原因,即:(1)Fe(Ⅲ)与NO3–同时作为电子受体,因竞争电子而受到抑制;(2)吸附态Fe(Ⅱ)物种还原NO3–,导致Fe(Ⅱ)累积减少,NO3–还原因产生的Fe(Ⅱ)的低速率而被抑制。 相似文献
9.
10.
基于细菌呼吸理论为基础的环境有毒物质降解为环境污染治理提供了新的策略和方法,是近年来研究的热点问题.细菌呼吸是自然界中一个最基本、最重要的生物代谢过程,具有很大的灵活性和多样性,且与生态环境密切相关.在厌氧条件下,细菌利用环境中多种有毒物质作为呼吸链末端电子受体进行厌氧呼吸,在有毒物质被还原甚至降解的同时实现电子在呼吸链上的传递,形成跨膜的质子浓度电势梯度,进而转化为其生长代谢所需的能量.细菌以环境有毒物质为电子受体的厌氧呼吸不断被发现,这对于深入理解细菌呼吸的本质具有重要的理论意义,同时对于有毒物质的降解及元素的生物地球化学循环具重要的环境学意义,对于提高对地球表面有毒物质污染生物修复策略的认识具有重要的现实意义.图1表1参45 相似文献
11.
Wool dyeing wastewater contains xenobiotic compounds that can be removed by biotechnological processes. Studies on various dyes showed that anaerobic processes are suitable to alter azo dyes as a first step of the biodegradation process. These compounds are reduced by anaerobic consortia to aromatic amines and its ultimate degradation can be achieved by a further aerobic treatment. Studies on degradation rate of an wool acid dye were performed in batch systems inoculated with anaerobic biomass. A commercial diazo dye, Acid Red 73, was added to the synthetic medium in which glucose was used as sole carbon source. Results indicated that the Acid Red 73 was partially degraded by a mixed culture of anaerobic bacteria and a decolorization of 90% was obtained. Kinetics studies on removal of the colour showed that the decolorization rate was several times faster than the degradation rate of glucose for a range of dye concentrations between 60 mg/L and 400 mg/L. A first order kinetic model was used for dye concentrations up to 200 mg/L. For higher concentrations a model similar to the Michaelis‐Menten equation was better fitted to the experimental data. 相似文献
12.
Mesozooplankton provide oxic and anoxic microhabitats for associated bacteria, whose carbon substrate usage activities complement those of the ambient bacteria. The metabolic profiles of bacterial communities associated with the calanoid copepod Acartia tonsa under aerobic and anaerobic conditions were examined in comparison with phytoplankton-associated bacteria. Carbon substrate usage by phytoplankton-associated bacteria was significantly different than that of copepod-associated bacteria in both aerobic and anaerobic conditions. Substrate utilization by copepod-associated bacteria was more dependent upon oxygen condition than whether the bacteria were located on the copepod exoskeleton or within the gut. Results suggest that gut bacteria were responsible for a large portion of anaerobic substrate usage by copepod-associated bacteria. The metabolic profiles of bacteria associated with six common zooplankton groups and free-living bacteria collected in July 2012 from the York River estuary, Virginia, (37°14′50.36″N, 76°29′58.03W) were also compared, and there were significant differences in their substrate utilization patterns between aerobic and anaerobic incubations, and among the different zooplankton groups. Through trophic interactions, phytoplankton-associated or free-living bacteria may be introduced to the anoxic zooplankton gut and its associated bacterial community. Inclusion of these anaerobic microenvironments and their microbial inhabitants increased the total number of substrates used by 57 % over what was used by aerobic phytoplankton-associated bacteria alone, and by 50 % over what was used by aerobic free-living bacteria in the York River. Therefore, the presence of zooplankton-associated microhabitats and their bacteria expanded the functionality of aquatic microbial communities and led to a more comprehensive substrate usage. 相似文献
13.
14.
分离获得4株能利用乳酸作为唯一碳源分别进行好氧生长和厌氧生长的光合细菌菌株,对其无细胞抽提液进行透析和乳酸转化为丙酮酸能力的测定.结果表明,这4株光合细菌在好氧和厌氧条件下对乳酸的代谢机制是不同的.对筛选获得的高乳酸转化能力的S1菌株的进一步研究表明,黑暗好氧条件下,S1菌株的乳酸代谢能力与生长呈正相关关系;而光照厌氧条件下,乳酸代谢酶的合成滞后于生长.图5表1参10 相似文献
15.
Yinghui Mo Liping Sun Lu Zhang Jianxin Li Jixiang Li Xiuru Chu Liang Wang 《Frontiers of Environmental Science & Engineering》2023,17(4):49
16.
Zhen Bi Deqing Wanyan Xiang Li Yong Huang 《Frontiers of Environmental Science & Engineering》2020,14(3):38
17.
C. R. Wilkinson 《Marine Biology》1978,49(2):169-176
Three taxonomically distant sponges Pericharax heteroraphis, Jaspis stellifera and Neofibularia irata contain phenotypically similar bacterial symbionts which differ from bacteria in the ambient water. These symbionts are predominant in the sponges and were detected after computer analysis of 526 heterotrophic bacterial strains tested for 76 characters. These facultative anaerobic symbionts metabolize a wide range of compounds and may be important in removing waste products while the sponges are not circulating water. The bacteria produce sticky-mucoid colonies and thus would contribute to sponge structural rigidity. The fourth sponge Ircinia wistarii contains a mixed aerobic population similar to that in the ambient water. The majority of the bacteria are located around the inhalant canals, facilitating the uptake of dissolved organic matter and oxygen from the incoming water. 相似文献
18.
19.
Bin Yan Cuihong Du Meilan Xu Wenchao Liao 《Frontiers of Environmental Science & Engineering》2012,6(6):806-814
The salt-tolerant Staphylococcus cohnii strain, isolated from textile wastewater, has been found effective on decolorizing several kinds of azo dyes with different structures. The optimal conditions for azo dye acid red B (ARB) decolorization by S. cohnii were determined to be pH = 7.0 and 30°C. The decolorization efficiency increased with the increase of the salinity concentration, and around 90% of ARB (100 mg·L?1) could be decolorized in 24 h when the salinity concentration was up to 50 g·L?1. Moreover, the strain could still decolorize 19% of ARB in 24 h even when the NaCl concentration was increased to 150 g·L?1. Meanwhile, the dependence of the specific decolorization rate by S. cohnii on the ARB concentration could be described with Michaelis-Menten kinetics (K m = 585.7mg·L?1, V max = 109.8 mg·g cell?1·h?1). The addition of quinone redox mediator, named 2-hydroxy-1,4-naphthoquinone and anthraquinone-2,6-disulfonate, significantly accelerated the decolorization performance of S. cohnii. Furtherly, the activities of azoreductase (0.55 ??mol·mg protein?1·min?1) and Nicotineamide adenine dinucleotide-dichlorophenol indophenol (NADH-DCIP) reductase (8.9 ??mol·mg protein?1·min?1) have been observed in the crude cell extracts of S. cohnii. The decolorization products of ARB were analyzed by HPLC-MS, and the results indicated the reductive pathway was responsible for azo dye decolorization by S. cohnii. 相似文献
20.
Degradation of azo dyes in water by Electro-Fenton process 总被引:19,自引:0,他引:19
The degradation of the azo dyes azobenzene, p-methyl red and methyl orange in aqueous solution at room temperature has been studied by an advanced electrochemical oxidation
process (AEOPs) under potential-controlled electrolysis conditions, using a Pt anode and a carbon felt cathode. The electrochemical
production of Fenton's reagent (H2O2, Fe2+) allows a controlled in situ generation of hydroxyl radicals (·OH) by simultaneous reduction of dioxygen and ferrous ions on the carbon felt electrode. In turn, hydroxyl radicals react
with azo dyes, thus leading to their mineralization into CO2 and H2O. The chemical composition of the azo dyes and their degradation products during electrolysis were monitored by high performance
liquid chromatography (HPLC). The following degradation products were identified: hydroquinone, 1,4-benzoquinone, pyrocatechol,
4-nitrocatechol, 1,3,5-trihydroxynitrobenzene and p-nitrophenol. Degradation of the initial azo dyes was assessed by the measurement of the chemical oxygen demand (COD). Kinetic
analysis of these data showed a pseudo-first order degradation reaction for all azo dyes. A pathway of degradation of azo
dyes is proposed. Specifically, the degradation of dyes and intermediates proceeds by oxidation of azo bonds and aromatic
ring by hydroxyl radicals. The results display the efficiency of the Electro-Fenton process to degrade organic matter.
Electronic Publication 相似文献