真菌对土壤中苯并[a]芘的共代谢降解

研究了模拟生物泥浆法修复多环芳烃污染土壤.选择了几种从石油污染土壤中分离出来的真菌,研究它们对土壤内苯并[a]芘的降解,并研究了土壤内共存底物:菲、芘、邻苯二甲酸对苯并[a]芘降解的影响,及其之间的共代谢过程.结果表明,芘可以促进镰刀菌、毛霉对苯并[a]芘的降解,并认为这是共代谢作用的结果;菲也可以促进镰刀菌对苯并[a]芘的降解,但抑制了毛霉和青霉对苯并[a]芘的降解;而邻苯二甲酸对青霉和毛霉降解苯并[a]芘的过程均有抑制作用.      

一株苯并[a]芘高效降解真菌的筛选与降解特性

从长期受多环芳烃(PAHs)污染的土壤中分离出一株能够降解苯并[a]芘(B[a]P)的真菌,经鉴定为绿色木霉(Trichoderma viride)(命名为BF-1),并对其以B[a]P为唯一碳源进行反复驯化,考察了B[a]P浓度、不同重金属和培养基对其降解能力的影响.结果表明,菌株BF-1在B[a]P浓度为5mg.L-1,32℃振荡培养约6d的条件下,降解速度最快,B[a]P的降解率达68.28%.BF-1在B[a]P浓度分别为10与25mg.L-1,32℃振荡培养6d的条件下,B[a]P的降解率分别为73.29%与87.36%.Cu2+(50mg.L-1)基本不影响BF-1对B[a]P的降解率;Cd2+(100mg.L-1)、Pb2+(300mg.L-1)对BF-1降解B[a]P有一定影响,但仍表现出较高的耐受能力;而Zn2+(200mg.L-1)对BF-1有明显的抑制作用.选用含5mg.L-1B[a]P的土豆葡萄糖液体培养基,6d后B[a]P的降解率为71.31%.对比前述实验结果表明,培养基对B[a]P降解率的影响并不明显.因此,BF-1的应用价值较高.     

一株苯并[a]芘降解菌-紫茉莉联合修复污染土壤的研究

从长期受多环芳烃(PAHs)污染的土壤中获得1株高效降解菌BB-1,经鉴定为巨大芽孢杆菌Bacillus megaterium.为了考察菌株的降解特性,将10和20 mg·L~(-1)的苯并[a]芘(B[a]P)加入到培养液中并在30℃下振荡培养8 d.结果表明,BB-1对不同浓度的B[a]P的降解率分别为52.1%和23.5%,B[a]P浓度为10 mg·L~(-1)时降解效果更优.将不同重金属外加到培养液中,Cu2+(50 mg·L~(-1))和Cd2+(100 mg·L~(-1))能在一定程度上影响BB-1对B[a]P的生物降解作用,但菌株仍有很强的耐受性;Zn2+(200 mg·L~(-1))和Pb2+(300 mg·L~(-1))会显著影响降解效果.为了研究菌BB-1与植物的联合降解修复作用,通过对比研究将该菌株加入到种植紫茉莉的B[a]P污染土壤中,在未加入BB-1的污染土壤中,紫茉莉在开花期和成熟期对B[a]P的降解率分别为27.42%±1.99%和51.31%±3.06%,在加入BB-1的污染土壤中降解率分别为68.22%±1.21%和77.16%±0.62%,可见加入菌株BB-1后能显著提高紫茉莉对土壤中B[a]P的降解效率.为确定降解作用的菌株来源,分别对比了非根际和根际土壤中的B[a]P含量,发现在开花期和成熟期任何一种处理的根际土中B[a]P残留浓度都小于非根际土,说明土壤中B[a]P的去除主要是源于根际的作用.在植物修复的基础上,添加能耐受一定重金属浓度的高效B[a]P降解菌,能提高B[a]P降解率,有望为日后大规模田间应用提供可靠的技术参数.     

杏鲍菇漆酶的诱导及其对苯并[a]芘的降解研究

杏鲍菇(Pleurotus eryngii)是一种常见的白腐真菌,具有产漆酶的能力。本研究采用液态方式培养杏鲍菇,考察了杏鲍菇的产漆酶性能和杏鲍菇培养液对苯并[a]芘的降解能力。研究结果发现铜离子对杏鲍菇产漆酶有明显的诱导作用,在液体培养基中添加1.0mmol/L铜离子,培养8天后漆酶活性提高8.3倍。杏鲍菇培养液对苯并[a]芘有较好的降解能力,培养7天后液体培养基中苯并[a]芘降解率达到89%。表明杏鲍菇在产漆酶和污染物降解方面具有良好的应用前景。     

多环芳烃共代谢对苯并[a]蒽微生物降解的影响及机制

利用¹⁴C同位素示踪技术，研究土壤中菲、蒽、芘3种底物对苯并[a]蒽（BaA）环境归趋的影响，高通量测序解析细菌群落响应.结果表明，3种底物均可以促进BaA的降解，添加蒽作为共代谢底物后，BaA矿化率比对照提高了2.5%，而添加菲、芘时，¹⁴C在土壤的结合态比对照升高4%，达总添加量的31%.共代谢底物改变了细菌共生网络的拓扑结构：添加底物蒽后，网络中的正连接比例显著升高，物种间以共生关系为主；菲、芘作为共代谢底物时，细菌物种间的负连接比例升高，暗示微生物种群竞争变激烈.推测蒽与BaA化合物结构相似并有相近的代谢途径，细菌共生性增强并直接促进了BaA的矿化.     

微生物对芘和苯并[a]芘污染土壤的修复

将枯草芽孢杆菌、白腐真菌和分离筛选菌群分别用于芘和苯并[a]芘污染土壤的修复,比较其修复性能,并对表面活性物剂Tween80和葡萄糖对修复效果的影响规律做了初步探讨.结果表明,60 d时,枯草芽孢杆菌和分离筛选菌修复芘污染的土壤,芘的残留率分别为7.58%±0.59%和8.69%±61.35%,空白残留率为48.18%...     

环境中苯并[a]芘的研究进展

苯并[a]芘(B[a]P)是国际公认的人类化学致癌物,在自然界中分布极广,卫生学中一般以它作为多环芳烃类致癌物的代表物.详细介绍了B[a]P的来源、理化性质、检测方法、毒性、致毒机理以及降解特性等方面最近的研究进展.展望了B[a]P今后重要的研究方向.     

苯并[a]芘降解菌SL-1的筛选、鉴定及其降解特性

从土壤中筛选出一株以苯并[a]芘为唯一碳源的高效降解菌SL-1,经形态观察、生理生化分析以及16SrDNA基因序列分析,该菌株鉴定为假单胞菌（Pseudomonassp．）。28℃震荡培养10d后,菌株SL-1对5mg·L^-1苯并[a]芘的降解率为35．7％;同时测定该降解菌的生长曲线、降解率变化曲线、最佳培养条件;土壤修复试验表明,42d时,降解菌SL-1对苯并芘的降解率达到76．3％。     

土壤铅-苯并[a]芘复合污染对小麦种子生长的影响研究

研究了土壤中低含量铅(Pb)-苯并[a]芘(B[a]P)复合污染对小麦种子萌发率、根伸长、芽伸长以及芽根比的影响,以期考察复合污染的生态效应并筛选具有指示土壤污染程度的指标.结果表明,小麦种子萌发率对Pb-B[a]P单一及复合污染均不敏感;Pb和B[a]P单一污染时小麦根伸长均受到一定程度的抑制作用;复合污染条件下Pb...     

用RBCA和CLEA模型推导土壤中苯并[a]芘的标准值

我国现行土壤环境质量标准中尚未包含苯并[a]芘(B[a]P). 分别应用2种国际上认可的RBCA和CLEA模型,获取了土壤中B[a]P的标准值,并对2种模型的计算结果和取值进行了比较. 结果表明,在目标风险水平设定为10-5时,RBCA和CLEA模型计算的住宅用地土壤B[a]P标准值分别为0.83和1.21 mg/kg;工业用地标准值分别为4.10和26.30 mg/kg. 2种模型住宅用地的标准差异不大,且与其他国家的标准水平基本接近;工业用地的标准差异较大,其中RBCA模型的结果更接近于其他国家标准,而CLEA模型的结果则明显偏高. 造成2种模型计算结果差异的原因主要来自于两方面,即模型的方法原理不同导致的暴露量计算差异以及采用的毒理学数据来源不同导致的数据水平差异. 2种模型暴露途径解析的结果均表明,经口摄入和皮肤接触是土壤污染物B[a]P人体暴露的主要途径,而口鼻吸入导致的暴露量很小.      

六株真菌对土壤中芘和苯并芘的降解及其动力学

研究了6株真菌对土壤中芘和苯并芘(BaP)的降解动态,用Michaelis-Menton和Monod动力学模型对结果进行拟合.结果表明,6株真菌对芘和BaP的降解速率有显著性差异,降解率相差不大.产黄青霉(Penicillium chrysogenum,SF04),在42d内对BaP的降解能力最强,可达71.31%,对芘的降解能力相对最弱.镰刀菌(Fusariumsp.,SF11),黑曲霉(Aspergillusniger,SF05),木霉(Trichodermasp.,SF02)和毛霉(Mucorsp.,SF06)42d对芘的降解率分别为86.22%,86.18%,85.41%,85.04%,对BaP的降解率分别为71.11%,69.44%,69.05%,69.72%.木霉(Trichodermasp.,SF02)和毛霉(Mucorsp.,SF06)对芘和BaP的降解速率均很快.     

苜蓿对多环芳烃菲污染土壤的修复作用研究

采用盆栽试验方法,研究了苜蓿(Medicago sativa L.)对多环芳烃菲污染土壤的修复作用.结果表明,多环芳烃菲对苜蓿的生长具有抑制作用,土壤中菲初始浓度越高抑制作用越明显.445.22 mg/kg条件下苜蓿茎叶和根的生物量最小,仅为无污染对照土壤的57.31%和31.20%.经过60 d的修复试验,苜蓿能够明显促进土壤中菲的降解.根际和非根际土壤中菲的去除率分别为85.68%～91.40%和75.25%～86.61%.同处理中根际土壤中菲残留浓度低于非根际土壤,而脱氢酶活性高于非根际土壤.无论是在非根际还是根际土壤中随着菲初始浓度增大,菲降解率和脱氢酶活性降低.脱氢酶活性与降解率的关系表明,脱氢酶活性与菲降解率显著正相关.所以植物根系的存在能够有效促进土壤中多环芳烃菲的降解.     

菲降解菌株GY2B的分离鉴定及其降解特性

对一株菲降解菌进行了鉴定并对其降解特性进行了研究.初步鉴定菌株GY2B为鞘氨醇单胞菌(Sphingomonassp.).菌株GY2B有较高的降解效率,当无机盐培养液中菲初始浓度为100mg/L时,48h内对菲降解率达到99.1%.添加100mg/L的葡萄糖和蛋白胨均可以促进菌株的生长和菲的降解,pH值为中性条件时对细胞的生长较为有利.GY2B菌株还能降解1-羟基-2-萘酸、2-萘酚、萘、水杨酸、邻苯二酚和苯酚等多种芳香化合物并利用其为碳源和能源生长繁殖.GY2B菌株对菲的降解可能通过水杨酸途径.     

Degradation of polycyclic aromatic hydrocarbons by Pseudomonas sp. JM2 isolated from active sewage sludge of chemical plant

It is important to screen strains that can decompose polycyclic aromatic hydrocarbons (PAHs) completely and rapidly with good adaptability for bioremediation in a local area. A bacterial strain JM2, which uses phenanthrene as its sole carbon source, was isolated from the active sewage sludge from a chemical plant in Jilin, China and identified as Pseudomonas based on 16S rDNA gene sequence analysis. Although the optimal growth conditions were determined to be pH 6.0 and 37℃, JM2 showed a broad pH and temperature profile. At pH 4.5 and 9.3, JM2 could degrade more than 40% of fluorene and phenanthrene (50 mg/L each) within 4 days. In addition, when the temperature was as low as 4℃, JM2 could degrade up to 24% fluorene and 12% phenanthrene. This showed the potential for JM2 to be applied in bioremediation over winter or in cold regions. Moreover, a nutrient augmentation study showed that adding formate into media could promote PAH degradation, while the supplement of salicylate had an inhibitive effect. Furthermore, in a metabolic pathway study, salicylate, phthalic acid, and 9-fluorenone were detected during the degradation of fluorene or phenanthrene. In conclusion, Pseudomonas sp. JM2 is a high performance strain in the degradation of fluorene and phenanthrene under extreme pH and temperature conditions. It might be useful in the bioremediation of PAHs.     

Characterization of phenanthrene degradation by strain Polyporus sp. S133

Polyporus sp. S133, a fungus collected from contaminated soil, was used to degrade phenanthrene, a polycyclic aromatic hydrocarbon, in a mineral salt broth liquid culture. A maximal degradation rate (92%) was obtained when Polyporus sp. S133 was cultured for 30 days with agitation at 120 r/min, as compared to 44% degradation in non-agitated cultures. Furthermore, the degradation was a ected by the addition of surfactants. Tween 80 was the most suitable surfactant for the degradation of phenanthrene by Polyporus sp. S133. The degradation rate increased as the amount of Tween 80 added increased. The rate in agitated cultures was about 2 times that in non-agitated cultures. The mechanism of degradation was determined through the identification of metabolites; 9,10-phenanthrenequinone, 2,2’-diphenic acid, phthalic acid, and protocatechuic acid. Several enzymes (manganese peroxidase, lignin peroxidase, laccase, 1,2-dioxygenase and 2,3-dioxygenase) produced by Polyporus sp. S133 were detected during the incubation. The highest level of activity was shown by 1,2-dioxygenase (187.4 U/L) after 20 days of culture.     

Plant enhanced degradation of phenanthrene in the contaminated soil

The degradative characteristics ofphenanthrene, microbial biomass carbon, plate counts ofheterotrophic bacteria and most probable number （MPN） of phenanthrene degraders in non-rhizosphere or rhizosphere soils with uninoculating or inoculating phenanthrene degraders were measured. At the initial concentration of 20 mg phenanthrene/kg soil, the half-lives of phenanthrene in uninoculated non-rhizosphere soil, uninoculated rhizosphere soil, inoculated non-rhizosphere soil, and inoculated rhizosphere soil were measured to be 81.5, 47.8, 15.1 and 6.4 d, respectively, and corresponding kinetic data fitted first-order kinetics. The highest degradation rate of phenanthrene was observed in inoculated rhizosphere soil. The degradative characteristics of phenanthrene were closely related to the effects of vegetation on soil microbial process. Vegetation could enhance the magnitude of rhizosphere microbial communities, microbial biomass content, and heterotrophic bacterial community, but barely influence those community components responsible for phenanthrene degradation. Results suggested that combination of vegetation and inoculation with degrading microorganisms of target organic contaminants was a better pathway to enhance degradation of the organic contaminants in soil.     

古水稻土中多环芳烃的分布特征及其来源判定

测定了马家浜文化(距今约6 000a)遗址2个剖面表层土壤、古代水稻土和古代旱地土壤、以及底层土壤中15种多环芳烃的含量,并对其可能来源进行了判定.结果表明,表层土壤中PAHs的含量分别为202.9μg·kg^-1和207.7μg·kg^-1,主要来源于大气沉降;古水稻土中PAHs含量明显降低,仅为56.0μg·kg^-1,但高于古旱地土壤及底层土壤。古旱地土壤及底层土壤PAHs含量在32.0～36.9μg·kg^-1.古水稻土中,2环和3环所占比例较大,达63%,萘和菲含量最高,而4环以上的多环芳烃含量较低.Phe/Ant和BaA/Chr比值和有机质¹³C-NMR图谱显示,古水稻土中的多环芳烃主要来源于水稻秸秆的焚烧,同时还原条件下的生物合成可能是其另一个重要来源.     

甲氰菊酯降解菌Sphingomonas sp.JQL4-5对污染土壤的生物修复

JQL4-5(Sphingomonas sp.)是1株从长期受农药污染土壤中分离的甲氰菊酯降解菌,考察了其在实验室模拟条件下对甲氰菊酯污染土壤的生物修复能力及其影响因素.结果表明,降解菌株在灭菌土壤中的降解效果要略好于未灭菌土壤,在土壤外源添加降解菌10⁶ CFU·g^-1,温度20～40 ℃, pH为6.5～7.5的条件下,该菌株能有效降解土壤中10～200 mg·kg^-1的甲氰菊酯.可以将其应用于甲氰菊酯污染土壤的生物修复.