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1.
土壤中高环多环芳烃微生物降解的研究进展   总被引:10,自引:0,他引:10       下载免费PDF全文
微生物修复是去除土壤中多环芳烃(PAHs)的主要措施。本文以微生物修复PAHs污染土壤的理论基础及其难点为主线,全面综述了土壤中高环PAHs的微生物降解机理。近年来,富集分离得到的以高环PAHs为唯一碳源和能源的优势降解菌逐渐增多,其中,主要是代谢降解四环PAHs的单株降解菌,一些降解菌还能以共代谢方式利用五环PAHs。高环PAHs污染土壤修复的一个难点是其低生物可利用性,微生物通过释放生物表面活性剂、形成生物膜以及分泌胞外多糖提高高环PAHs的生物可利用性,从而加速其降解。真菌和细菌联合作用能增强污染土壤实地修复的效果。因此,通过微生物修复技术来去除土壤中PAHs具有环境友好性、经济适用性以及可持续应用性。  相似文献   

2.
多环芳烃污染土壤生物修复研究进展   总被引:1,自引:0,他引:1       下载免费PDF全文
多环芳烃 (Polycyclic aromatic hydrocarbons,PAHs) 是一类广泛分布于环境中的持久性污染物,结构稳定、难以降解,对生态环境和生物具有“三致”毒害性,其环境去除和修复备受关注。绿色、安全、经济的生物修复技术被广泛应用于PAHs污染土壤的修复。本文从土壤中PAHs的来源、迁移、归趋和污染水平总结了目前我国土壤多环芳烃污染的基本状况;归纳了具有PAHs降解作用的微生物、植物种类及机理;比较了微生物修复、植物修复和联合修复3类主要的生物修复技术。指出植物与微生物的互作机理的解析,抗逆菌株、植株的筛选与培育,实际应用的安全和效能评估应成为多环芳烃污染土壤修复领域未来的研究方向。  相似文献   

3.
荒漠草地中氮添加与多环芳烃降解的关系   总被引:1,自引:0,他引:1       下载免费PDF全文
多环芳烃作为环境污染物中一类极为重要的物质,探索它的去除方法吸引了全球环境学者及政府的高度重视。大气氮沉降在过去几十年不断增加,已影响到陆地生态系统氮循环过程。但目前,氮沉降与多环芳烃降解之间的关系尚不明确。通过在新疆克拉玛依市石油化工厂附近的荒漠草地上,模拟氮沉降实验,通过在4氮添加梯度(CK=0; N1=10; N2=30; N3=90 kg N hm~(-2) a~(-1))上调查土壤中16种优先控制多环芳烃的含量和总量(∑PAHs),以及它们与生物非生物环境因子(土壤环境因子、土壤酶活性和土壤微生物功能多样性)之间的关系,旨在揭示氮沉降对多环芳烃降解的影响。结果表明:除苊烯(Acenaphthylene)和苊(Acenaphthene)两种多环芳烃在4个N添加梯度上未检测到含量外,∑PAHs和其他14种优先控制多环芳烃在土壤中的含量均随氮添加量增加显著减小(N2≤N3N1CK)(P0.01);对照样地(CK)在施氮前后,低高分子多环芳烃含量的比值1.00,且0.40荧蒽(Fluoranthene)/[(荧蒽(Fluoranthene)+芘(Pyrene)]0.50,石油污染物是当地土壤中多环芳烃的主要来源;9月份克拉玛依市荒漠草地土壤中∑PAHs约(28.91±2.32) mg/kg,属于多环芳烃重污染土壤;广义线性混合效应模型结果显示,在大多数情况下,∑PAHs和14种多环芳烃的含量与土壤有机质、铵态氮、硝态氮、总氮、有效磷和脲酶活性显著相关(P0.05),但其与生物非生物环境因子之间的回归关系在不同种类多环芳烃之间差异较大。综上可知,土壤中多环芳烃的降解是一个非常复杂的过程,它是自身属性、植物根系和土壤微生物等多重因子相互共同作用的结果。在干旱区荒漠草地中,氮添加能提升土壤中营养物质的可利用性、植物根系和土壤微生物的活性,有利于降解土壤多环芳烃。  相似文献   

4.
土壤-植物系统中多环芳烃和重金属的行为研究   总被引:14,自引:0,他引:14  
对土壤中多环芳烃和重金属的行为研究表明,与对照相比,0—20cm以上表土层存在多环芳烃和重金属积累,20cm以下土层未发现积累;与春、秋两次采样结果相比,土壤中多环芳烃的含量有所下降,表明土壤微生物对多环芳烃有一定降解作用,且其降解程度与土壤-植物系统的生态结构有关.菲在地下水中检出浓度较高,表明这一污染物有向下迁移的可能性.此外,柳树对土壤中重金属Cd的积累有明显的削减与净化作用.本研究表明,严格限制污水中多环芳烃和重金属的污染负荷以及设计合理的生态结构是避免多环芳烃和重金属在土壤中积累的关键.  相似文献   

5.
微生物降解多环芳烃的研究进展   总被引:12,自引:1,他引:11  
多环芳烃是一类长久存在于环境中,具有毒性、致突变与致癌等特性的环境优先污染物。本文对降解多环芳烃的微生物类群进行了阐述,介绍了在土壤与厌氧条件下细菌降解多环芳烃的研究情况,最后介绍了降解多环芳烃的相关酶类以及分子生物学的研究,并对消除环境中多环芳烃的相关生物技术提出展望。  相似文献   

6.
新疆石油污染土壤中微生物多环芳烃(polycyclic aromatic hydrocarbons,PAHs)降解功能基因研究甚少,且环境因子和功能基因之间相关性仍不清楚。【目的】揭示新疆石油污染砂质土壤自然衰减过程中多环芳烃降解关键基因结构和变化规律。【方法】以新疆准东油田为研究区,分析同一采油区不同石油污染年限土壤理化因子和多环芳烃含量变化,采用扩增子测序研究石油自然衰减过程中多环芳烃降解酶基因结构变化规律,利用Mental检验探讨其环境驱动因子。【结果】石油污染时间1年和3年的土壤中有多项理化指标与背景土存在显著性差异,而污染5年土壤与背景土之间仅2项指标具有显著性差异,随石油自然衰减逐渐恢复至正常。石油污染1年的土壤中16种多环芳烃除苊烯和?以外,其余14种多环芳烃均高于石油污染3年和5年土壤,多环芳烃总量和含油率污染1年土壤均显著高于污染3年和5年的土壤,多环芳烃会在污染后短时间内迅速被降解。扩增子测序结果显示,萘双加氧酶基因分类操作单元(operational taxonomic units,OTUs)序列随污染年限延长逐渐增多;芳环羟化双加氧酶基因OTUs序列BLAST(...  相似文献   

7.
[背景] 真菌和细菌被认为在多环芳烃污染土壤生物修复过程中发挥协同作用,目前在真实土壤体系中开展真菌-细菌协同降解研究较少。[目的] 研究真菌和细菌对不同种类多环芳烃降解的差异及对蒽和苯并[a]蒽的生物强化与协同作用。[方法] 选用多环芳烃降解真菌和细菌各一株,在液体纯培养体系下分析它们对不同种类多环芳烃降解的差异,在土壤体系中采用放射性同位素示踪技术研究2种微生物对蒽和苯并[a]蒽的生物强化与协同作用。[结果] 供试细菌鞘脂菌NS7能够很好地降解低环种类多环芳烃,以蒽作为唯一碳源时可以将其完全降解,在复合污染条件下对菲、蒽、荧蒽、芘等降解效果突出(>90%),对苯并[a]芘降解效果较差(9.76%)。相比而言,供试真菌糙皮侧耳菌对苯并[a]芘具有更好的降解效果(21.18%),对低环多环芳烃降解效果明显不如降解菌NS7。在自然土壤中,蒽和苯并[a]蒽具有明显不同的矿化效率,分别为18.61%和4.28%,在蒽污染土壤中加入鞘脂菌NS7并未显著提高蒽的矿化率(P>0.05),相比而言,苯并[a]蒽污染土壤中加入糙皮侧耳显著提高了污染物矿化效率(2.24倍),表明真菌和细菌在土壤环境中的定殖存活能力可能影响了生物强化效果。采用灭菌土壤排除土著微生物的竞争排斥作用,研究了真菌菌丝对生物强化降解的影响,发现在蒽污染土壤中,真菌菌丝的迁移作用显著提高了细菌鞘脂菌NS7对污染物的矿化率,从1.75%提高到5.91%;而在苯并[a]蒽灭菌污染土壤中,接种糙皮侧耳却没有发现苯并[a]蒽矿化率提高的现象,表明自然土壤中真菌强化降解苯并[a]蒽的作用可能是源于真菌菌丝促进污染物和土著降解菌的接触,而非直接来自真菌本身。[结论] 细菌能够很好地降解低环种类多环芳烃,而真菌对高环种类多环芳烃降解效果较好。真菌可能通过菌丝促进土著微生物在土壤中的迁移,增大多环芳烃和土著降解菌的接触,从而促进了多环芳烃降解。研究加深了对多环芳烃污染土壤生物强化修复的认识,对发展基于真菌-细菌协同作用的生物强化与调控技术提供理论指导。  相似文献   

8.
多环芳烃 (PAHs)是一类普遍存在的环境中的优先有机污染物 ,在土壤中残留持久并难以降解 ,因此给环境和人体健康带来潜在危胁 [5] 。研究表明 ,微生物降解是去除 PAHs的主要途径 [6]。微生物能够以利用 PAHs作为碳源与能源和共代谢两种方式降解 PAHs[7] 。泥浆反应器作为生物修复技术之一 ,具有处理周期短 ,降解条件易于控制和处理效果好的特点[8,9] ,目前已成为一种重要的处理技术 ,在欧、美等发达国家 ,受到广泛重视。Grosser[10 ]等人发现 ,把微生物从污染地区分离培养后 ,接种到污染土壤中可大大提高芘的降解率。泥浆反应器中污染…  相似文献   

9.
为揭示根际效应对多环芳烃降解的影响机制,建立恰当的植物-微生物联合修复模式,本研究向含有微生物及多环芳烃(芘和苯并\[a\]芘)的微宇宙中加入三叶草根系分泌物,分析其对多环芳烃降解的影响,研究降解过程中微生物加氧酶和16S rDNA基因拷贝数的变化,并对具有多环芳烃降解能力的微生物进行鉴定.结果表明: 分枝杆菌M1具有降解多环芳烃的能力;三叶草根系分泌物总有机碳(TOC)浓度为35.5 mg·L-1时,芘和苯并\[a\]芘降解率明显提高,分枝杆菌加氧酶基因所占比例增加,表明其促进了分枝杆菌对芘和苯并\[a\]芘的降解;在降解过程中,加氧酶基因拷贝数明显增加,而16S rDNA数量增加不明显,表明前者与多环芳烃降解过程有关,而后者和微生物数量有关.三叶草根系分泌物使分枝杆菌加氧酶基因拷贝数明显增加,从而促进了分枝杆菌对多环芳烃的降解.
  相似文献   

10.
多环芳烃(polycyclic aromatic hydrocarbon,PAHs)是一类对环境有严重危害的持久性有机污染物。具有高生物富集性、致癌性、致毒性和难降解性,修复治理PAHs污染环境备受国内外政府及学者的关注。目前主要采用物理、化学以及生物方法对多环芳烃污染的土壤和水体进行修复。其中生物修复是一种高效、经济和生态可承受的环保技术,具有成本低、无二次污染等优点。本文从植物修复、微生物修复以及植物-微生物联合修复方面,阐述了国内外生物修复PAHs污染的最新研究进展。指出了生物修复PAHs污染环境需要进一步解决的问题,并对未来发展趋势进行了展望。  相似文献   

11.
The influence of growth medium on cometabolic degradation of polycyclic aromatic hydrocarbons (PAHs) was investigated when Sphingomonas sp. strain PheB4 isolated from surface mangrove sediments was grown in either phenanthrene-containing mineral salts medium (PMSM) or nutrient broth (NB). The NB-grown culture exhibited a more rapid cometabolic degradation of single and mixed non-growth substrate PAHs compared to the PMSM-grown culture. The concentrations of PAH metabolites were also lower in NB-grown culture than in PMSM-grown culture, suggesting that NB-grown culture removed metabolites at a faster rate, particularly, for metabolites produced from cometabolic degradation of a binary mixture of PAHs. Cometabolic pathways of single PAH (anthracene, fluorene, or fluoranthene) in NB-grown culture showed similarity to that in PMSM-grown culture. However, cometabolic pathways of mixed PAHs were more diverse in NB-grown culture than that in PMSM-grown culture. These results indicated that nutrient rich medium was effective in enhancing cometabolic degradation of mixed PAHs concomitant with a rapid removal of metabolites, which could be useful for the bioremediation of mixed PAHs contaminated sites using Sphingomonas sp. strain PheB4.  相似文献   

12.
芘在土壤中的共代谢降解研究   总被引:38,自引:4,他引:34  
高分子量多环芳烃(PAHs)的降解通常以共代谢方式进行,研究比较了高分子量多环芳烃代表种类芘作为唯一C源和能源的降解过程和有共代谢底物存在下的降解过程,结果表明,25d后前者中芘的降解率57%,而后者中芘的降解率为80%,且有共代谢底物存在下,芘在降解过程中关衰期缩短;水扬酸,邻苯二甲酸,琥珀酸钠能作为共代谢底物提高芘的降解率,琥珀酸钠效果最好,芘和低要子量多环芳烃之间也有共代谢关系,菲促进了芘的降解,但萘未出现同样的结果,此外,这阐明了共代谢原理和适宜作高分子量多环芳烃共代谢底物的物质。  相似文献   

13.
Biodegradation of a mixture of PAHs was assessed in forest soil microcosms performed either without or with bioaugmentation using individual fungi and bacterial and a fungal consortia. Respiratory activity, metabolic intermediates and extent of PAH degradation were determined. In all microcosms the low molecular weight PAH’s naphthalene, phenanthrene and anthracene, showed a rapid initial rate of removal. However, bioaugmentation did not significantly affect the biodegradation efficiency for these compounds. Significantly slower degradation rates were demonstrated for the high molecular weight PAH’s pyrene, benz[a]anthracene and benz[a]pyrene. Bioaugmentation did not improve the rate or extent of PAH degradation, except in the case of Aspergillus sp. Respiratory activity was determined by CO2 evolution and correlated roughly with the rate and timing of PAH removal. This indicated that the PAHs were being used as an energy source. The native microbiota responded rapidly to the addition of the PAHs and demonstrated the ability to degrade all of the PAHs added to the soil, indicating their ability to remediate PAH-contaminated soils.  相似文献   

14.
The objectives of this study were to isolate and evaluate microorganisms with the ability to degrade high molecular weight polycyclic aromatic hydrocarbons (PAHs) in the presence of synthetic surfactants. Stenotrophomonas maltophilia VUN 10,010, isolated from PAH-contaminated soil, utilized pyrene as a sole carbon and energy source and also degraded other high molecular weight PAHs containing up to seven benzene rings. Various synthetic surfactants were tested for their ability to improve the PAH degradation rate of strain VUN 10,010. Anionic and cationic surfactants were highly toxic to this strain, and the Tween series was used as a growth substrate. Five nonionic surfactants (Brij 35, Igepal CA-630, Triton X-100, Tergitol NP-10, and Tyloxapol) were not utilized by, and were less toxic to, strain VUN 10,010. MSR and log Km values were determined for fluoranthene, pyrene, and benzo[a]pyrene in the presence of these nonionic surfactants and their apparent solubility was increased by a minimum of 250-fold in the presence of 10 g L-1 of all surfactants. The rate of pyrene degradation by strain VUN 10,010 was enhanced by the addition of four of the nonionic surfactants (5-10 g L-1); however, 5 g L-1 Igepal CA-630 inhibited pyrene degradation and microbial growth. The specific growth rate of VUN 10,010 on pyrene was increased by 67% in the presence of 10 g L-1 Brij 35 or Tergitol NP-10. The addition of Brij 35 and Tergitol NP-10 to media containing a single high molecular weight PAH (four and five benzene rings) as the sole carbon source increased the maximum specific PAH degradation rate and decreased the lag period normally seen for PAH degradation. The addition of Tergitol NP-10 to VUN 10,010 cultures which contained a PAH mixture (three to seven benzene rings) substantially improved the overall degradation rate of each PAH and increased the specific growth rate of VUN 10,010 by 30%. Evaluation of the use of VUN 10,010 for degrading high molecular weight PAHs in leachates from surfactant-flushed, weathered, PAH-contaminated sites is warranted. Copyright 1998 John Wiley & Sons, Inc.  相似文献   

15.
The effects of nutrient addition on the in situ biodegradation of polycyclic aromatic hydrocarbons in creosote contaminated soil were studied in soil columns taken from various soil strata at a wood preserving plant in Norway. Three samples were used: one from the topsoil (0–0.5 m), one from an organic rich layer (2–2.5 m) and one from the sandy aquifer (4.5–5 m). The addition of inorganic nitrogen and phosphorous stimulated the degradation of polycyclic aromatic hydrocarbons (PAHs) in the top soil and the aquifer sand. These two soils, which differed strongly in contamination levels, responded similarly to nutrient addition with the corresponding degradation of 4-ring PAHs. The ratio between available nitrogen (N) and phosphorous (P) might explain the degree of degradation observed for the 4-ring PAHs. However, the degree of degradation of 3-ring PAHs did not significantly increase after nutrient addition. An increase in the respiration rate, after nutrient addition, could only be observed in the topsoil. In the aquifer sand, 4-ring PAH degradation was not accompanied by an increase in the respiration rate or the number of heterotrophic micro-organisms. PAH degradation in the organic layer did not respond to nutrient addition. This was probably due to the low availability of the contaminants for micro-organisms, as a result of sorption to the soil organic matter. Our data illustrate the need for a better understanding of the role of nutrients in the degradation of high molecular weight hydrocarbons for the successful application of bioremediation at PAH contaminated sites.  相似文献   

16.
The purpose of this study was to develop a fungal bioremediation method that could be used for soils heavily contaminated with persistent organic compounds, such as polyaromatic hydrocarbons (PAHs). Sawmill soil, contaminated with PAHs, was mixed with composted green waste (1:1) and incubated with or without fungal inoculum. The treatments were performed at the laboratory and field scales. In the laboratory scale treatment (starting concentration 3500 mg kg−1, sum of 16 PAH) the high molecular weight PAHs were degraded significantly more in the fungal-inoculated microcosms than in the uninoculated ones. In the microcosms inoculated with Phanerochaete velutina, 96% of 4-ring PAHs and 39% of 5- and 6-ring PAHs were removed in three months. In the uninoculated microcosms, 55% of 4-ring PAHs and only 7% of 5- and 6-ring PAHs were degraded. However, during the field scale (2 t) experiment at lower starting concentration (1400 mg kg−1, sum of 16 PAH) the % degradation was similar in both the P. velutina-inoculated and the uninoculated treatments: 94% of the 16 PAHs were degraded in three months. In the field scale experiment the copy number of gram-positive bacteria PAH-ring hydroxylating dioxygenase genes was found to increase 1000 fold, indicating that bacterial PAH degradation also played an important role.  相似文献   

17.
多环芳烃微生物降解基因的研究进展   总被引:12,自引:2,他引:10  
郑乐  刘宛  李培军 《生态学杂志》2007,26(3):449-454
多环芳烃(PAHs)是环境中普遍存在的一类有机污染物,微生物的降解是PAHs去除的主要途径。近年来,有关PAHs微生物降解途径和代谢产物的研究已有很多报道。小分子PAHs一般可以直接被微生物降解,而大分子PAHs则需要微生物以共代谢的方式降解。在过去20年中,微生物降解PAHs的基因相继被发现,各种基因在调控PAHs降解过程中的功能也越来越清晰。本文概述了PAHs微生物降解基因方面的研究进展,详细介绍了微生物对萘、菲的降解基因,最后对PAHs微生物降解基因的应用前景进行了展望。  相似文献   

18.
Stenotrophomonas maltophilia KB2 used in this study is known to metabolise broad range of aromatic compounds including phenol, some chloro and methylphenols, benzoic acids, catochols and others. To study the applicability of the strain for degradation of mononitrophenols in monosubstrate as well as cometabolic systems its degradation potential in the presence of mononitrophenols or different aromatic compounds of plant origin was tested. Stenotrophomonas maltophilia KB2 strain was not able to degrade any of mononitrophenols used in the single substrate experiments. Effect of additional carbon source on nitrophenols degradation revealed that presence of benzoate, 4-hydroxybenzoate or 3,4-dixydroxybenzoate stimulate transformation of 2-nitrophenol, 3-nitrophenol as well as 4-nitrophenol. Depending on growth substrate and mononitrophenol used, decrease in cometabolite concentration was from 25 to 45%. Obtained results suggest that Stenotrophomonas maltophilia KB2 strain could be potentially used for cometabolic degradation of nitrophenols in the presence of aromatic acids, for the bioremediation of contaminated sites.  相似文献   

19.
Municipal wastewaters contain a multitude of organic trace pollutants. Often, their biodegradability by activated sludge microorganisms is decisive for their elimination during wastewater treatment. Since the amounts of micropollutants seem too low to serve as growth substrate, cometabolism is supposed to be the dominating biodegradation process. Nevertheless, as many biodegradation studies were performed without the intention to discriminate between metabolic and cometabolic processes, the specific contribution of the latter to substance transformations is often not clarified. This minireview summarizes current knowledge about the cometabolic degradation of organic trace pollutants by activated sludge and sludge-inherent microorganisms. Due to their relevance for communal wastewater contamination, the focus is laid on pharmaceuticals, personal care products, antibiotics, estrogens, and nonylphenols. Wherever possible, reference is made to the molecular process level, i.e., cometabolic pathways, involved enzymes, and formed transformation products. Particular cometabolic capabilities of different activated sludge consortia and various microbial species are highlighted. Process conditions favoring cometabolic activities are emphasized. Finally, knowledge gaps are identified, and research perspectives are outlined.  相似文献   

20.
Batch experiments on the simultaneous utilization of phenol (primary substrate) and 4-chlorophenol (cometabolic secondary substrate) demonstrated two critical substrate interactions. First, the cometabolic degradation of 4-chlorophenol was proportional to the rate of phenol oxidation, which provided the electrons for the initial monooxygenase reaction. Second, 4-chlorophenol inhibited the oxidation of the primary substrate, phenol. Modeling analyses of the degradation of phenol alone and of phenol and 4-chlorophenol together showed that the proportionality between phenol and 4-chlorophenol degradation rates averaged 0.1 mg 4-CP/mg phenol, which corresponds to 0.5% of the electrons generated by phenol oxidation being used as a cosubstrate for the monooxygenase reaction of 4-chlorophenol. In addition, modeling analyses suggest that 4-chlorophenol was a noncompetitive inhibitor of phenol oxidation for high phenol concentrations, but a competitive inhibitor for low phenol concentrations.Abbreviations GC gas chromatography - FID flame-ionization detector - DO dissolved oxygen - 4-CP 4-chlorophenol - Ph phenol - RLS relative least squares criterion - NAD nicotinamide adenine dinucleotide - NADP nicotinamide adenine dinucleotide phosphate  相似文献   

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