福建漳江口水环境中滴滴涕（DDTs）的分布与溯源

采用气相色谱(GC-ECD)方法分析了漳江口水环境中表层水、沉积物和水生生物体内滴滴涕(DDTs)的污染水平,初步研究了其在多介质中的含量、转移分配规律,并根据其沿江分布规律、组成特征,结合三氯杀螨醇同步调查结果进行了溯源分析.结果表明: 漳江口表层水中的DDTs平均含量为枯水期10.5 ng·L^-1(未检出～20.1 ng·L^-1)、丰水期28.3 ng·L^-1 (未检出～45.2 ng·L^-1)、平水期5.03 ng·L^-1 (未检出～18.8 ng·L^-1);表层沉积物中DDTs含量(以干质量计)为1.87～144 ng·g^-1,平均17.3 ng·g^-1;11种水生生物中DDTs的含量范围为1.09～432 ng·g^-1,平均37.0 ng·g^-1.与其他地区相比,漳江口表层水和沉积物中的DDTs残留属于中等水平.DDT在沉积物中的富集因子为1185;在生物体中的富集因子平均为2534,富集能力依次为水生植物<虾类<贝类<鱼类.DDTs沿江分布基本呈下降趋势,推断其残留与船舶防污剂释放关系不大,主要来源于陆源性污染.组成特征分析显示,漳江口DDTs主要来源于环境中的早期残留,而Y-8站(江心岛后)近期有新的DDTs输入,可能与三氯杀螨醇的使用有关.同步调查结果显示,Y-8站表层水和沉积物中均检出三氯杀螨醇,且含量最高,近期存在三氯杀螨醇的施用.     

DBP降解菌株XJ1的分离鉴定及其降解特性

目的：从湘江底泥筛选分离出能够高效降解邻苯二甲酸二丁酯（DBP）的菌株,对其进行鉴定和降解特性研究。方法：采用DBP为唯一碳源和能源的无机盐培养基,通过富集培养、平板划线分离得到一株优势菌,编号为XJ1。采用形态学、生理生化、（G＋C）mol%和16SrDNA序列分析进行鉴定。采用高效液相色谱测定菌株XJ1在摇瓶中对DBP的降解能力,并进行DBP代谢产物的分析和底物广谱性测试。结果：鉴定该菌株为Sphingomonsasp.。摇瓶实验结果表明：最佳降解条件为温度35℃,初始pH为7.0,转速150r/min;在最佳的降解条件下,40h之内DBP可完全降解。HPLC-UV检测出的中间代谢产物为邻苯二甲酸单丁酯（MBP）和邻苯二甲酸（PA）。底物广谱性实验表明菌株XJ1能够利用邻苯二甲酸二甲酯、邻苯二甲酸二乙酯等邻苯二甲酸酯类化合物。结论：菌株XJ1对DBP具有高效的降解能力,在处理含有邻苯二甲酸酯类化合物污染的生物修复方面具有独特的应用潜力。     

高效芘降解菌N12的分离鉴定与降解特性

以芘为目标降解物,利用选择性富集培养方法,从沈抚灌区污染土壤中分离到一株高效芘降解菌N12,经生理生化试验和16S rDNA测序分析,该菌被鉴定为分枝杆菌属（Mycobacterium sp.）.菌株N12能以菲、苊、芴和芘为唯一碳源和能源生长,不能以蒽、萘和苯并芘为唯一碳源和能源生长.在菲和芘共同存在的情况下菌株N12可降解苯并芘,9 d内对苯并芘降解率可达79.0%.摇瓶降解试验表明,菌株N12可在7 d内将100 mg·L^-1的芘降解94.4%,14 d内将其完全降解;可将600 mg·L^-1的芘在7 d内降解56.1%,14 d内降解95.5%.添加葡萄糖可促进N12对芘的降解.菌株N12是一株优良的多环芳烃降解菌,可作为多环芳烃污染土壤生物修复的菌种资源.     

厌氧微生物菌群XH-1对2,4,6-三氯苯酚的降解特性

有机污染物2,4,6-三氯苯酚(2,4,6-TCP)普遍存在于地下水和河流底泥等厌氧环境中。为了探究厌氧微生物菌群XH-1对2,4,6-TCP的降解能力,本研究以2,4,6-TCP为底物,接种XH-1建立微宇宙培养体系,并以中间产物4-氯苯酚(4-CP)和苯酚为底物分别进行分段富集培养,利用高效液相色谱分析底物的降解转化,同时基于16S rRNA基因高通量测序分析微生物群落结构变化。结果表明: 2,4,6-TCP(122 μmol·L^-1)以0.15 μmol·d^-1的速率在80 d内被完全降解转化,降解中间产物分别为2,4-二氯苯酚(2,4-DCP)、4-氯苯酚和苯酚,所有中间产物最终在325 d被完全降解。高通量测序结果表明,脱卤杆菌和脱卤球菌可能驱动2,4,6-TCP还原脱氯,其中,脱卤球菌可能在4-CP的脱氯转化中发挥重要作用,并与丁酸互营菌和产甲烷菌联合作用彻底降解2,4,6-TCP。     

一株敌草胺降解菌的分离鉴定及降解性能

为探讨酰胺类除草剂敌草胺的微生物降解机理和土壤中敌草胺降解的生物强化性能,从长期使用敌草胺的烟田土壤中分离到一株敌草胺降解细菌菌株,命名为LGY06.经形态特征、生理生化特性及16S rDNA序列分析将其鉴定为蜡状芽孢杆菌.在纯培养条件下,菌株LGY06对敌草胺的降解符合一级动力学特征,7 d内对50 mg·L^-1敌草胺降解率达到75.7%;LGY06降解敌草胺的最适温度和最适pH值分别为35 ℃和8.0.通过气相色谱-质谱鉴定了菌株LGY06降解敌草胺的降解产物并分析了其降解途径,α-萘酚和丙酰胺是主要的降解产物,LGY06对敌草胺的作用方式主要有脱烷基、氧化(或水解),为矿化过程.室内模拟条件下,LGY06能有效促进土壤中敌草胺残留的降解,与未接种灭菌土、非根际土和根际土相比,敌草胺在接种LGY06土壤中的降解半衰期分别缩短了79.5%、36.6%和41.1%.     

邻苯二甲酸酯的污染现状及微生物降解研究进展

作为环境内分泌干扰物的一种,邻苯二甲酸酯(PAEs)作为增塑剂被广泛应用于生产、生活诸多方面,目前已在大气、水、土壤等各种环境介质中被检测到,其污染普遍性和对整个生态系统的危害性已受到越来越多的关注。微生物降解被认为是去除环境中PAEs的最佳途径。本文综述了PAEs的污染现状及其微生物降解研究进展,为深入探讨PAEs污染的微生物修复提供参考,并对其微生物降解研究前景进行了展望。     

3株多环芳烃高效降解菌株的分离鉴定及降解特性

筛选分离降解多环芳烃(PAHs)的优势菌种对开展多环芳烃污染生态系统修复具有重要的现实意义。本研究以焦化厂周围受多环芳烃污染的土壤为菌源,经过富集培养驯化和平板分离,获得11株能降解多环芳烃的菌株。通过形态观察、生理生化特征及16S rRNA序列比对对菌株进行鉴定,筛选出3株PAHs高效降解菌,分别命名为DJ-3、DJ-8、DJ-10。经16S rRNA序列分析鉴定,DJ-3为假单胞菌属、DJ-8为克雷伯氏菌属、DJ-10为芽孢杆菌属。对菌株降解能力的研究表明,3株菌(DJ-3、DJ-8、DJ-10)培养7 d后对混合多环芳烃中菲(200 mg·L^-1)、芘(200 mg·L^-1)和萘(160 mg·L^-1)的降解率分别为48.9%～65.9%、38.9%～43.1%和57.6%～64.9%。3株菌对多环芳烃混合样品(1200 mg·L^-1)的降解率分别为49.1%、44.5%、53.9%,远高于其他8株筛选菌,为PAHs高效降解菌株。3种菌株两两之间和三者组合均无拮抗关系。研究结果将为构建高效的多环芳烃降解菌群、提高多环芳烃原位污染土壤的生物修复效果奠定基础。     

多氯联苯微生物脱氯研究进展

多氯联苯(polychlorinated biphenyls,PCBs)是环境中典型的氯代持久性有机污染物.微生物脱氯是一种氯代有机物自然降解模式,对全球PCBs特别是高氯代同系物消减起到至关重要的作用.厌氧条件下高氯代PCBs能够发生脱氯反应,使其毒性大大降低,脱氯后形成的低氯代化合物可以进一步好氧降解,直至完全矿化.本文综述了PCBs生物脱氯的研究进展,介绍了微生物脱氯反应的机理和特征、参与微生物脱氯过程的专性脱氯菌等,探讨了该微生物过程的影响因素及厌氧脱氯与好氧降解耦合的意义,并对脱氯微生物群落的复杂代谢网络研究、专性脱氯新菌种筛选及其污染地实际修复应用等未来研究方向进行了展望.     

甲烷及三氯乙烯驯化对垃圾填埋场覆盖土细菌群落结构的影响

对典型垃圾填埋覆盖土进行CH₄原位富集和三氯乙烯(TCE)驯化,研究了其生物氧化能力和微生物群落结构变化.覆盖土CH₄氧化速率为0.20～0.87 μmol·g^-1 soil·h^-1,TCE降解速率为0.009～0.013 mg·L^-1·h^-1,其中山东垃圾填埋场覆盖土土样甲烷氧化活性高于广东、上海和重庆地区土样.通过Illumina MiSeq测序技术分析了α多样性和驯化前后微生物菌群结构变化规律.结果表明: 在所有被注释的操作分类单元聚类结果中,细菌OTUs分配为39个门,85个纲,562个属,富集驯化后变形杆菌门、拟杆菌门、绿弯菌门和酸杆菌门仍为各土样的优势菌群,所占比例之和高于77.4%;γ-变形杆菌纲、β--变形杆菌纲、α-变形杆菌纲、放线菌纲和酸杆菌纲所占比例之和高于26.5%.嗜甲基菌属、厌氧绳菌属、节杆菌属和假单胞菌属经TCE驯化后,其相对丰度呈增加趋势.表明在覆盖土氯代烃生物降解过程中,除了被广泛认可的甲烷氧化菌异养共代谢机制以外,还存在非甲烷共代谢机制和氯代烃自养降解机制.     

微生物技术去除抗生素残留污染的研究进展

抗生素进入环境会对生物造成深远的影响,如何去除抗生素的残留引起许多国家的关注。抗生素在环境中主要发生生物降解,而具有抗性的微生物菌株发挥主要的功效,因此近些年利用微生物技术处理抗生素残留污染成为研究热点。本文对具有抗生素降解功能的微生物资源和利用复合菌系处理抗生素残留的生物技术进行概括总结,并对微生物处理技术的不足和发展方向进行展望。     

Aerobic degradation of phthalic acid by Comamonas acidovoran Fy-1 and dimethyl phthalate ester by two reconstituted consortia from sewage sludge at high concentrations

Microbial degradation of phthalic acid (PA) and dimethyl phthalate ester (DMPE) under aerobic conditions was investigated using a pure species of bacteria and two consortia from sewage sludge. Five morphologically distinct microorganisms were obtained in pure culture and identified, and tested for the capability of degrading phthalate and DMPE. Comamonas acidovorans strain Fy-1 showed the highest ability to degrade high concentrations of phthalate (2600 mg/l) within 48 h. Two reconstituted consortia of microorganisms, one comprising Pseudomonas fluorescens, P. aureofaciens and Sphingomonas paucimobilis, and the other of Xanthomonas maltophilia and S. paucimobilis, were effective in completely degrading DMPE (400 mg/l) in 48–96 h. The three-species consortium appeared to be more effective in the degradation of DMPE, and both consortia proceeded via formation of mono-methyl phthalate (MMP) and then phthalatic acid before mineralization. This study suggests that high concentrations of the endocrine-disrupting chemicals phthalate and DMPE can be mineralized in wastewater treatment systems by indigenous microorganisms.     

Anaerobic biodegradability of phthalic acid isomers and related compounds

All three phthalic acid isomers ( ortho, meta and para benzene dicarboxylic acid) are produced in massive amounts, and used in the chemical industry as plasticizers or for the production of polyester. Wastestreams generated during the production of phthalate isomers generally contain high concentrations of aromatic acids. To study the potential biodegradability of these primarily anthropogenic compounds in anaerobic bioreactors, biodegradability studies were performed. Compounds tested were benzoate, ortho-phthalate, isophthalate, terephthalate, dimethyl phthalate, dimethyl terephthalate, para-toluate and para-xylene. Seed materials tested were two types of granular sludge and digested sewage sludge. It was found that all phthalate isomers and their corresponding dimethyl-esters, could be completely mineralized by all seed materials studied. Lag phases required for 50% degradation of these compounds, ranged from 17 to 156 days. The observed degradation curves could be explained by growth of an initially small amount of organisms in the inoculum with the specific ability to degrade one phthalate isomer. The observed order in the length of the lag phases for the phthalate isomers is: phthalate < terephthalate < isophthalate. This order appears to be related to the environmental abundancy of the different phthalate isomers. The initial step in the degradation pathway of both dimethyl phthalate esters was hydrolysis of the ester sidechain, resulting in the formation of the corresponding mono-methyl-phthalate isomer and phthalate isomer. The rate limiting step in mineralization of both dimethyl phthalate and dimethyl terephthalate was found to be fermentation of the phthalate isomer. Para-toluate was degraded only by digested sewage sludge after a lag phase of 425 days. The observed degradation rates of this compound were very low. No mineralization of para-xylene was observed. In general, the differences in the lag phases between different seed materials were relatively small. These results indicate that the time needed for the start-up of anaerobic bioreactors treating wastewaters containing phthalic acid isomers, depends little on the microbial composition of the seed material applied, but may take several months.     

Biomineralization of an organophosphorus pesticide,Monocrotophos, by soil bacteria

AIMS: To study biomineralization of Monocrotophos (MCP) and identify the metabolites formed during biodegradation. METHODS AND RESULTS: Two cultures, namely Arthrobacter atrocyaneus MCM B-425 and Bacillus megaterium MCM B-423, were isolated by enrichment and adaptation culture technique from soil exposed to MCP. The isolates were able to degrade MCP to the extent of 93% and 83%, respectively, from synthetic medium containing MCP at the concentration of 1000 mg x l(-1), within 8 d, under shake culture condition at 30 degrees C. The cultures degraded MCP to carbon dioxide, ammonia and phosphates through formation of one unknown compound--Metabolite I, valeric or acetic acid and methylamine, as intermediate metabolites. The enzymes phosphatase and esterase, reported to be involved in biodegradation of organophosphorus compounds, were detected in both the organisms. CONCLUSIONS:Arthrobacter atrocyaneus MCM B-425 and B. megaterium MCM B-423 isolated from soil exposed to MCP were able to mineralize MCP to carbon dioxide, ammonia and phosphates. SIGNIFICANCE AND IMPACT OF THE STUDY: Pathway for biodegradation of MCP in plants and animals has been reported. A microbial metabolic pathway of degradation involving phosphatase and esterase enzymes has been proposed. The microbial cultures could be used for bioremediation of wastewater or soil contaminated with Monocrotophos.     

Bioavailability of water-polluting sulfonoaromatic compounds

Highly substituted arenesulfonates are chemically stable compounds with a range of industrial applications, and they are widely regarded as being poorly degradable. We did enrichment cultures for bacteria able to utilise the sulfonate moiety of 14 compounds, and we obtained mixed cultures that were able to desulfonate each compound. The products formed were usually identified as the corresponding phenol, but because we could not obtain pure cultures, we followed up these findings with quantitative work in pure cultures of, e.g., Pseudomonas putida S-313, which generated the same phenols from the compounds studied. Many of these phenols are known to be biodegradable, or to be subject to binding to soil components. We thus presume that the capacity to degrade aromatic sulfonates extensively is widespread in the environment, even though the degradative capacity is spread over several organisms and conditions. Received: 9 February 1999 / Revision received: 7 April 1999 / Accepted: 9 April 1999     

Degradation of chloro- and methyl-substituted benzoic acids by a genetically modified microorganism

Degradation of 3-chlorobenzoic acid (3CB), 4-chlorobenzoic acid (4CB), and 4-methylbenzoic acid (4MB) as single substrates (carbon sources) and as a substrate mixture were studied in batch and continuous culture using the genetically modified microorganism Pseudomonas sp. B13 FR1 SN45P. The strain was able to mineralize the single compounds as well as the substrate mixture completely. Conversion of the three compounds in the substrate mixture proceeded simultaneously. Maximum specific substrate conversion rates were calculated to be 0.9 g g(-1) h(-1) for 3 CB and 4CB and 1.1 g g(-1) h(-1) for 4MB. Mass balances indicated the transient accumulation of pathway intermediates during batch cultivations. Hence, the rate limiting step in the degradative pathway is not the initial microbial attack of the original substrate or its transport through the cell membrane. Degradation rates on 3CB were comparable to those of the parent strain Pseudomonas sp. B13. The stability of the degradation pathways of strain Pseudomonas sp. B13 FR1 SN45P could be demonstrated in a continuous cultivation over 3.5 months (734 generation times) on 3CB, 4MB, and 4CB, which were used as single carbon sources one after the other.     

A novel pathway for mineralization of the thiocarbamate herbicide molinate by a defined bacterial mixed culture

A bacterial mixed culture able to mineralize molinate was established, through enrichment, using mineral medium with molinate as the only carbon, nitrogen and energy source. The combination of five cultivable isolates, purified from the enrichment culture, permitted the reconstitution of a degrading consortium. Both enrichment and defined cultures were able to mineralize molinate without accumulation of degradation products by the end of the growth. Among the five isolates constituting the defined mixed culture, an actinomycete, strain ON4, was essential for biodegradation, being involved in the cleavage of the thioester bond of molinate, the initial step of the degradation pathway. Isolate ON4 was able to grow on molinate at concentrations below 2 mM, with the accumulation of ethanethiol and diethyl disulphide. These sulphur compounds were toxic to strain ON4 when accumulating at higher concentrations. However, this inhibitory effect was avoided by the presence of other members of the mixed culture, out of which isolates ON1 and ON2 were observed to consume ethanethiol and diethyl disulphide. In this way, interactions among defined mixed culture members involve metabolic and detoxifying association.     

Co-culture of defined bacteria to degrade seven sulfonated aromatic compounds: efficiency,rates and phenotypic variations

Summary A co-culture, consisting of five defined bacteria [e.g., T. Thurnheer, T. Köhler, A. M. Cook, and T. Leisinger: J Gen Microbiol 132:1215–1220], was able to degrade at least seven substituted benzenesulfonic acids in continuous culture. HPLC, total organic carbon analyses and colourimetric analyses showed that the sulfonated compounds could be completely degraded to biomass, SO ₄ ^2- , NH ₄ ⁺ and CO₂. The maximum observed degradation rate was 138 mg of C/h·1. The five organisms were Alcaligenes sp. strain 0–1 (substrates benzenesulfonic acid, 4-methylbenzenesulfonic acid and 2-aminobenzenesulfonic acid), two Pseudomonas spp., strains T-2 (substrates 4-methylbenzenesulfonic acid and 4-sulfobenzoic acid) and PSB-4 (substrate 4-sulfobenzoic acid) and two unidentified rods, strains M-1 (substrates benzenesulfonic acid, 4-methylbenzenesulfonic acid and 3-aminobenzenesulfonic acid) and S-1 (substrates 4-aminobenzenesulfonic acid and 4-hydroxybenzenesulfonic acid). The system was operated for over 18 months with five sulfonates, and no competition was detected amongst the four organisms present, because all organisms were still present (100% of the population after 7 months, 55% after 18 months). Many bacteria isolated from the continuous culture after 18 months showed substrate ranges different from those of the original strains. The most common occurrence (33% of the population) was the appearance of organisms which could degrade 2-aminobenzenesulfonic acid and 4-sulfobenzoic acid. Several cases of the loss of a character were seen but only rarely (1%) was a net gain of characters observed. After 30 months, only two (of five) parents were present (35% of the population) and some isolates could utilize all seven substrates on solid media.     

Biodegradation of phthalic acid esters in river water and activated sludge.

The primary and ultimate biodegradability of phthalic acid, monobutyl phthalate, and five structurally diverse phthalic acid ester plasticizers in river water and activated sludge samples were determined via ultraviolet spectrophotometry, gas chromatography, and CO2 evolution. The compounds studied underwent rapid primary biodegradation in both unacclimated river water and acclimated activated sludge. When activated sludge acclimated to phthalic acid esters was used as the inoculum for the CO2 evolution procedure, greater than 85% of the total theoretical CO2 was evolved. These studies demonstrate that the phthalic acid ester plasticizers and intermediate degradation products readily undergo ultimate degradation in different mixed microbial systems at concentrations ranging from 1 to 83 mg/liter.     

The humification of high-moor peat

Summary It has been observed that dark coloured substances are formed by soil micro-organisms (Pseudomonas, Arthrobacter-Corynebacterium-Nocardia group, spore forming bacteria and Streptomyces) from aromatic compounds,e.g. phenol, benzoic acid, guaiacol, toluene, phthalic acid, catechol, tyrosine, and tryptophane. The dark-brown to black substances formed by these organisms possess humus-like qualities and have the appearance of dopplerite. Reducing substances reacting in the cold with triphenyl tetrazolium chloride are formed as intermediates. It is suggested that these intermediary substances are quinones, or semiquinones and that these occur as free radicals which subsequently polymerize to humus-like substances.     

Selection and isolation of bacteria capable of degrading dinoseb (2-sec-buty-4,6-dinitrophenol)

Dinoseb (2-sec-butyl-4,6-dinitrophenol) has been a widely used herbicide that persists in some contaminated soils, and has been found in groundwaters, causing health and environmental hazards. Persistence in some soils may stem from a lack of dinoseb-degrading organisms. We established a chemostat environment that was strongly selective for aerobic (liquid phase) and anaerobic (sediment phase) bacteria able to degrade dinoseb. The chemostat yielded five taxonomically diverse aerobic isolates that could transform dinoseb to reduced products under microaerophilic or denitrifying conditions, but these organisms were unable to degrade the entire dinoseb molecule, and the transformed products formed multimeric material. The chemostat also yielded an anaerobic consortium of bacteria that could completely degrade dinoseb to acetate and CO₂ when the Eh of the medium was less than-200 mV. The consortium contained at least three morphologically different bacterial species. HPLC analysis indicated that dinoseb was degraded sequentially via several as yet unidentified products. Degradation of these intermediates was inhibited by addition of bromoethane sulfonic acid. GC-MS analysis of metabolites in culture medium suggested that regiospecific attacks occurred non-sequentially on both the nitro groups and the side-chain of dinoseb. The consortium was also able to degrade 4,6-dinitro-o-cresol, 3,5-dinitrobenzoic acid, 2,4-dinitrotoluene, and 2,6-dinitrotoluene via a similar series of intermediate products. The consortium was not able to degrade 2,4-dinitrophenol. To our knowledge, this is the first report of strictly anaerobic biodegradation of an aromatic compound containing a multicarbon, saturated hydrocarbon side chain.Abbreviations BESA bromoethane sulfonic acid - RAMM reduced anaerobic mineral medium