克拉玛依石油污染土壤微生物群落结构及其代谢特征

为了分析克拉玛依油区内土壤中正构烷烃含量间的差异,微生物群落生理多样性、微生物代谢活性在不同石油污染梯度土壤中的变化规律。本研究采用GC、平板稀释法、Biolog微平板技术探讨了土壤微生物群落特征在3种不同污染程度下的变化情况。研究表明,石油污染土壤烷烃含量与微生物代谢活性呈显著负相关(r=-0.783, p<0.05)。随着石油污染程度增加微生物数量呈下降趋势,不同石油污染土壤中细菌数量占决定优势,细菌>真菌>放线菌。不同石油污染土壤微生物群落对6大碳源的利用体现出差异。主成分分析(PCA)表明,清洁土壤与石油污染土壤对底物利用有明显差异。石油污染严重土样碳源利用率为"酯类>酸类>胺类>氨基酸类>单糖/糖苷/聚合糖类>醇类"。本研究成果为后期修复污染土壤时调整投入的碳源底物等提供科学帮助。     

恩诺沙星对土壤微生物群落功能多样性的影响

为了评价恩诺沙星(enrofloxacin)对土壤微生物群落的影响,借助BIOLOG检测法比较了不同浓度恩诺沙星影响下的土壤微生物的群落特征。结果表明,各添加药物组与空白对照组的土壤微生物群落代谢多样性差异显著(P<0.05),空白对照组土壤微生物在BIOLOG微平板上的平均每孔颜色变化率(AWCD)和微生物代谢多样性指数(丰富度和多样性)显著高于添加药物组;药物显著影响微生物群落对BIOLOG微平板中碳源的利用能力,较低浓度的恩诺沙星(0.01μg/g)就显著影响了土壤微生物群落对α-Ketobutyric Acid、L-Phenylalanine、1-Erythritol、D-Xylose等碳源的利用代谢能力(P<0.05),且土壤微生物群落利用各类碳源的能力随药物浓度加大而降低。由此可见,恩诺沙星在土壤中残留时对土壤微生物的影响不容忽视。     

猫儿山不同海拔植被带土壤微生物群落功能多样性

为研究中亚热带森林土壤微生物群落功能多样性特征及其随海拔梯度的变化,应用Biolog微平板技术,对猫儿山不同海拔植被带(常绿阔叶林(EBF)、落叶阔叶混交林(DBF)、针阔混交林(CBF))土壤微生物群落功能多样性差异进行了比较。结果表明,不同海拔植被带土壤微生物群落功能多样性差异显著。土壤平均颜色变化率(AWCD)随培养时间延长而逐渐增加,随着海拔升高,土壤AWCD值逐渐降低,大小顺序为EBFDBFCBF。土壤微生物群落Shannon指数和丰富度指数的总体趋势为EBF最高,DBF次之,CBF最低。不同海拔植被带土壤微生物群落均匀度指数之间差异不显著。不同海拔植被带土壤微生物对不同碳源的利用能力存在差异,其中EBF利用率最高,CBF利用率最低,氨基酸类、胺类和酯类碳源为各海拔植被带土壤微生物利用的主要碳源。主成分分析结果表明,主成分1和主成分2分别能解释变量方差的40.42%和15.97%,在主成分分离中起主要贡献作用的是酯类、胺类和氨基酸类碳源。土壤理化性质与土壤微生物群落功能多样性之间的相关性分析结果表明,微生物群落多样性的Shannon指数与全钾(TK)呈极显著正相关(P0.01),与含水量呈极显著负相关(P0.01),与总有机碳(TOC)、全氮(TN)、速效氮(AN)、有效P(AP)之间的相关性显著(P0.05)或极显著(P0.01),且为负相关。土壤TK含量和含水量可能是造成不同海拔土壤微生物群落功能多样性差异的主要原因。     

不同生态条件下油松(Pinus tabulaeformis)菌根根际土壤微生物群落

利用BIOLOG代谢指纹方法分析了陕南商南和陕北安塞不同生态条件下油松菌根根际土壤微生物群落。结果表明,安塞油松和商南油松菌根根际微生物对糖类和氨基酸类碳源较易利用,商南油松菌根根际微生物总体上代谢碳源的种类和活性远大于安塞油松,而且对同类碳源的代谢商南油松的AWCD比安塞油松均高出2倍多。安塞油松菌根根际微生物以氨基酸类代谢群为优势类群,商南油松以糖类代谢群为优势类群。微生物群落多样性指数和微生物群落主成分分析（PCA）指标均表明商南油松和安塞油松菌根根际土壤微生物群落有明显不同,起分异作用的碳源主要为糖类,其次是羧酸类和氨基酸类。商南油松菌根根际土壤微生物群落AWCD极显著高于安塞油松（P〈0．01）,细菌数量显著高于安塞油松（P〈0．05）,Shannon指数和丰富度指数达极显著性差异（P〈0．01）,商南油松和安塞油松菌根侵染率差异不显著,但菌根生物量差异达极显著水平（P〈0．01）。相关性分析表明,菌根生物量与丰富度指数、AWCD呈极显著正相关,与Shannon指数呈显著正相关,但是与菌根侵染率相关性不显著。在商南温暖潮湿丘陵区油松菌根根际微生物活性、群落大小和多样性高于安塞油松,在安塞黄土高原干旱区微生物群落稳定性强于商南油松。     

不同生态条件下油松(Pinus tabulaeformis)菌根根际土壤微生物群落

利用BIOLOG代谢指纹方法分析了陕南商南和陕北安塞不同生态条件下油松菌根根际土壤微生物群落。结果表明,安塞油松和商南油松菌根根际微生物对糖类和氨基酸类碳源较易利用,商南油松菌根根际微生物总体上代谢碳源的种类和活性远大于安塞油松,而且对同类碳源的代谢商南油松的AWCD比安塞油松均高出2倍多。安塞油松菌根根际微生物以氨基酸类代谢群为优势类群,商南油松以糖类代谢群为优势类群。微生物群落多样性指数和微生物群落主成分分析（PCA）指标均表明商南油松和安塞油松菌根根际土壤微生物群落有明显不同,起分异作用的碳源主要为糖类,其次是羧酸类和氨基酸类。商南油松菌根根际土壤微生物群落AWCD极显著高于安塞油松（P<0.01）,细菌数量显著高于安塞油松（P<0.05）,Shannon指数和丰富度指数达极显著性差异（P<0.01）,商南油松和安塞油松菌根侵染率差异不显著,但菌根生物量差异达极显著水平（P<001）。相关性分析表明,菌根生物量与丰富度指数、AWCD呈极显著正相关,与Shannon指数呈显著正相关,但是与菌根侵染率相关性不显著。在商南温暖潮湿丘陵区油松菌根根际微生物活性、群落大小和多样性高于安塞油松,在安塞黄土高原干旱区微生物群落稳定性强于商南油松。     

黄土丘陵沟壑区地形变化对土壤微生物群落功能多样性的影响

研究黄土高原丘陵沟壑区破碎地形对土壤微生物功能多样性的影响,对于理解复杂地形区生态过程与系统功能的空间变化具有重要意义。选择陕西省安塞县陈家洼为研究区,依据坡面地形变化选择不同坡位土壤,采用Biolog微平板培养法探究地形变化对土壤微生物群落功能多样性的影响。实验发现,土壤微生物群落培养的平均颜色变化率(AWCD)增长曲线总的呈现出坡下部坡中部坡上部的规律,且坡下部AWCD值与坡中部、坡上部间差异显著(P0.05);坡下部土壤微生物群落功能多样性显著高于坡中部和坡上部,但不同土层深度(0—10 cm、10—20 cm)间无显著性差异(P0.05);对土壤微生物群落功能多样性差异贡献较大的碳源是糖类、羧酸类和多酚化合物类碳源;土壤含水率高低是不同坡位土壤微生物群落功能多样性差异显著的主要原因;微生物群落丰富度(H)和均一度(D)与土壤全氮含量正相关,优势度(U)反之,土壤全碳、全磷和p H对土壤微生物群落结构和功能多样性差异作用不显著。     

石油污染地土壤微生物群落的碳源利用特性

应用Biolog微平板技术,研究了大庆油田开采36年的石油污染土壤不同土层（0～10 cm、10～20 cm、20～30 cm）土壤微生物群落对碳源的利用特性.结果表明: 石油污染明显提高了土壤微生物群落的代谢活性,3个土层的微生物代谢强度均高于无污染土壤（CK）,不同土层之间的微生物代谢强度存在显著差异,其中20～30 cm土层的碳源代谢能力最强,其次为10～20 cm土层,0～10 cm土层最弱.石油污染使10～20 cm和20～30 cm土层土壤微生物群落对底物碳源利用种类增多,代谢功能的多样性增强,而0～10 cm土层则无明显变化.10～20 cm土层土壤微生物对底物碳源的利用由对照土壤的羧酸类居多转为石油污染土壤的碳水化合物最多,而20～30 cm土层土壤微生物对底物碳源的利用以羧酸类居多.说明石油污染土壤的微生物群落具有独特的群落结构和特点.     

科尔沁沙地小叶锦鸡儿固沙群落土壤微生物功能多样性

为探讨科尔沁沙地流动沙丘上建立小叶锦鸡儿固沙植被后土壤微生物群落代谢功能的变化,采用Biolog-ECO微平板检测法,研究了9、16和26年生人工群落以及流动沙丘和天然小叶锦鸡儿群落土壤微生物碳源代谢的多样性变化特征.结果表明:在培养的264 h内,流动沙丘土壤微生物平均颜色变化率,以及对羧酸类、糖类、多聚物类、氨基酸类、胺类和芳香类化合物类的代谢能力明显高于人工群落;随着人工群落年龄的增加,土壤微生物代谢碳源种类增加,26年生人工群落土壤微生物的碳源代谢模式已接近天然群落.流动沙丘建立小叶锦鸡儿植被后,土壤微生物群落碳源代谢功能多样性和均匀度指数下降;随着植物群落发育年龄的增长,微生物功能多样性逐渐提高.     

锶污染下燕麦对土壤酶活性和微生物群落功能多样性的影响

为了评价燕麦对金属锶(Sr)污染土壤的修复效果,通过土培盆栽试验,在土壤中添加Sr,共设置6个处理:25 mg/kg Sr(CK)、100 mg/kg Sr(L)、250 mg/kg Sr(H)、25 mg/kg Sr+燕麦(CK+燕麦)、100 mg/kg Sr+燕麦(L+燕麦)和250 mg/kg Sr+燕麦(H+燕麦)。从土壤酶(转化酶、磷酸酶、蛋白酶、脲酶和脱氢酶)活性和土壤微生物群落功能多样性来评价燕麦在锶污染土壤植物修复中的作用。结果表明:燕麦显著提高了脲酶和脱氢酶活性。燕麦显著提高了锶污染土壤微生物对31种碳源的平均利用率(AWCD),并提高了锶污染土壤条件下微生物群落的Shannon多样性指数(H)、Shannon均匀度指数(E)和碳源利用丰富度指数(S),降低了Shannon优势度指数(D)。主成分分析表明种植燕麦显著增加了锶污染土壤中微生物群落功能多样性。与未种植处理(L和H)相比,L+燕麦处理中羧酸类碳源和聚合物类碳源的利用率分别增加了19%和31%,H+燕麦处理中羧酸类碳源和聚合物类碳源的利用率分别增加了24%和41%。因此,在锶污染土壤中,燕麦显著提高了土壤酶活性,改善了微生物功能多样性。     

砷矿区农田土壤微生物群落碳源代谢多样性

采用Biolog方法研究了砷(As)矿区农田土壤微生物碳源利用多样性及其与土壤化学性质的关系.结果表明:3种土壤的N、P、K、有机质(OM)、Cu和Zn全量依次为中As＞高As＞低As土壤.中As和高As土壤微生物平均吸光度以及多样性指数(H'、D、U)显著高于低As土壤.主成分分析与生理碳代谢指纹图谱分析表明,中As和高As土壤微生物对糖类、氨基酸类等碳源的利用程度显著高于低As土壤.典范对应分析显示,影响土壤微生物群落碳源代谢的主要有全P、OM、全Pb、全Zn、全N和pH,全As并不是最主要的影响因子.可见,养分是影响长期污染土壤微生物群落结构和功能多样性的主要因素.     

The Dynamic Change of Microbial Communities in Crude Oil-Contaminated Soils from Oil Fields in China

To study the biodegradability of microbial communities in crude oil contamination, crude oil-contaminated soil samples from different areas of China were collected. Using polyphasic approach, this study explored the dynamic change of the microbial communities during natural accumulation in oil field and how the constructed bioremediation systems reshape the composition of microbial communities. The abundance of oil-degrading microbes was highest when oil content was 3–8%. This oil content is potentially optimal for oil degrading bacteria proliferation. During a ～12 months natural accumulation, the quantity of oil-degrading microbes increased from 10⁵ to 10⁸ cells/g of soil. A typical sample of Liaohe (LH, oil-contaminated site near Liaohe River, Liaoning Province, China) was remediated for 50 days to investigate the dynamic change of microbial communities. The average FDA (a fluorescein diacetate approach) activities reached 0.25 abs/hr·g dry soil in the artificially enhanced repair system, 32% higher than the 0.19 abs/hr·g dry soil in natural circumstances. The abundance of oil-degrading microbes increased steadily from 0.001 to 0.068. During remediation treatment, oil content in the soil sample was reduced from 6.0% to 3.7%. GC–MS analysis indicated up to 67% utilization of C₁₀–C₂₀ normal paraffin hydrocarbons, the typical compounds that undergo microbial degradation.     

高羊茅草对盐碱地原油污染土壤微生物的影响

采用常规土壤理化分析和Biolog-Eco微孔板鉴定系统,研究了松嫩平原盐碱土地区高羊茅草的生长对原油污染土壤pH、总盐含量和微生物群落的影响.结果表明: 石油污染导致表征土壤微生物代谢活性的平均颜色变化率(AWCD)、物种多样性指数和碳源利用数增加, 微生物碳源利用模式发生改变.高羊茅草对石油污染土壤有较好的修复作用,降低了土壤pH和石油烃(TPH)含量,提高了土壤含水率.高羊茅草根际土壤的AWCD和碳源利用丰富度指数明显高于裸地土壤,为其根际微生物的生长发育提供了适宜的环境.     

Functional gene diversity of soil microbial communities from five oil-contaminated fields in China

To compare microbial functional diversity in different oil-contaminated fields and to know the effects of oil contaminant and environmental factors, soil samples were taken from typical oil-contaminated fields located in five geographic regions of China. GeoChip, a high-throughput functional gene array, was used to evaluate the microbial functional genes involved in contaminant degradation and in other major biogeochemical/metabolic processes. Our results indicated that the overall microbial community structures were distinct in each oil-contaminated field, and samples were clustered by geographic locations. The organic contaminant degradation genes were most abundant in all samples and presented a similar pattern under oil contaminant stress among the five fields. In addition, alkane and aromatic hydrocarbon degradation genes such as monooxygenase and dioxygenase were detected in high abundance in the oil-contaminated fields. Canonical correspondence analysis indicated that the microbial functional patterns were highly correlated to the local environmental variables, such as oil contaminant concentration, nitrogen and phosphorus contents, salt and pH. Finally, a total of 59% of microbial community variation from GeoChip data can be explained by oil contamination, geographic location and soil geochemical parameters. This study provided insights into the in situ microbial functional structures in oil-contaminated fields and discerned the linkages between microbial communities and environmental variables, which is important to the application of bioremediation in oil-contaminated sites.     

Integration of biosorption and biodegradation in a fed-batch mode for the enhanced crude oil remediation

Microbial bioremediation of oil-contaminated sites is still a challenge due to the slower rate and susceptibility of microbes to a higher concentration of oil. The poor bioavailability, hydrophobicity, and non-polar nature of oil slow down microbial biodegradation. In this study, biodegradation of crude oil is performed in fed-batch mode using an oil-degrader Pseudomonas aeruginosa to address the issue of substrate toxicity. The slower biodegradation was integrated with faster biosorption for effective oil remediation. Highly fibrous and porous sugarcane bagasse was surface modified with hydrophobic octyl groups to improve the surface-oil interactions. The microbe showed 2 folds enhanced oil degradation in the fed-batch study, which was further increased by 1·5 folds in the integrated biosorption coupled biodegradation approach. The biosorption-assisted biodegradation approach supported the microbial growth to 2 folds higher than the fed-batch study without biosorbent. The analysis of biosurfactant production indicated the 3 folds higher concentration in fed-batch modes as compared to batch study. In the integrated strategy, the concentration of contaminant (oil) reduces to quite a tolerable level to microbes, which improved effective metabolism and thus overall biodegradation. This study puts forward a promising strategy for improved degradation of hazardous hydrophobic contaminants in a sustainable, economic and eco-friendly manner.     

Crude Oil Biodegradation by a Soil Indigenous Bacillus sp. Isolated from Lavan Island

The application of microorganisms for removing crude oil pollution from contaminated sites as a type of bioremediation has long been a matter of study in scientific communities. In this study, 35 morphologically different spore-forming Bacilli were isolated from an oil-contaminated soil in Lavan Island. The objective of this study was to investigate the oil-biodegrading ability of these indigenous bacilli. Therefore, their biosurfactant production, using Du Neuy ring, and the crude oil aliphatic and aromatic content alteration after bacterial treatment, respectively, using gas chromatography and high-performance liquid chromatography, were studied. An isolate with high endurance of a wide range of temperature and pH and optimized growth at 30°C and pH 6.8 that could reduce the surface tension from 60 to 40 mN/m and cause the most alteration in aliphatic and aromatic content of crude oil was selected. Using biochemical and molecular analyses of 16SrRNA, this suitable bacterium for oil biodegradation was characterized as Bacillus cereus sp. 4.     

News & Notes: Bioremediation of Crude Oil Contamination with Acinetobacter sp. A3

Acinetobacter sp. A3 is able to extensively degrade Bombay High Crude Oil (BHCO) and utilize it as the sole source of carbon. A total degradation of 70% BHCO was noted by the end of 120 h of growth of Acinetobacter sp. A3 under shake flask condition, 60% of which was due to biodegradation. In crude oil-contaminated soil (5%) amended with Acinetobacter sp. A3, there was both an increase in colony-forming units (CFU) and crude oil degradation. This is in contrast to a decrease in CFU of the indigenous microorganisms and lower degradation in unamended soil within the same 30-day period. Also, Acinetobacter sp. A3-treated soil permitted better germination of Mung beans (Phaseolus aureus) and growth as evidenced by better length and weight of the plants and chlorophyll content of its leaves, which was attributed to the reduction in phytotoxicity of the crude oil owing to its degradation. This crude oil degradative capability of Acinetobacter sp. A3 could be exploited for bioremediation purposes. Received: 16 December 1996 / Accepted: 10 February 1997     

Biodegradation of wood in crude oil-polluted soil

A field investigation (April–November) in Nigeria showed that biodegradation of obeche (Triplochiton scleroxylon) wood blocks was initially retarded in crude oil-contaminated soil but later became enhanced as indicated by loss of compression resistance. Further indication of this pattern was the detection of soft-rot cavities and basidiomycete fungi after 2–3 months exposure when compared to control blocks in uncontaminated soil. Laboratory tests with Pleurotus sp., Trametes sp., Gloeophyllum sp. (basidiomycetes) and Chaetomium sp. (soft-rot fungus) confirmed that degradation of crude oil-coated obeche blocks was markedly retarded without the presence of hydrocarbon-degrading bacteria. The filtrate of hydrocarbon-degrading Pseudomonas sp. grown in mineral salt/crude oil medium for 3–4 weeks supported growth of the test fungi better than in carboxymethyl cellulose medium but less than in potato dextrose broth. Similarly, wood blocks immersed in the filtrate became significantly more susceptible to fungal degradation. Pseudomonas sp. from stationary phase growth in crude oil medium depleted residual sugar in basidiomycete-degraded sawdust with a concomitant marked increase in its population. It may be concluded that readily metabolizable products of crude oil degradation by soil organisms and the removal of residual sugar which may have prevented catabolite repression of cellulases, culminated in increased attack on the wood by soil-borne wood-decomposing organisms.     

PLFA Analyses of Microbial Communities Associated with PAH-Contaminated Riverbank Sediment

Sediment contaminated with polycyclic aromatic hydrocarbons (PAHs) is widely distributed in aquatic ecosystems. The microbial community structure of riverbank PAH-contaminated sediments was investigated using phospholipid-derived fatty acid (PLFA) analysis. Surface and subsurface riverbank sediment was collected from a highly contaminated site and from an uncontaminated site along the Mahoning River, OH. PAH concentrations, physical sediment characteristics, and other microbial community parameters (biomass as phospholipid phosphate (PLP) and activity) were also measured. PAHs were detected in all samples but were only quantifiable in the contaminated (250?μg/g?g(-1)) subsurface sediment. Subsurface samples from both locations showed very similar PLP values and distribution of PLFAs, with 27-37?% of the microbial community structure being composed of sulfate reducing and other anaerobic bacteria. Principal components analysis indicated no correlation between PAH contamination and PLFA diversity. Although PLP and phospholipid fatty acid measurements of bacterial communities did not reflect the environmental differences among sites, the highly PAH-contaminated sediment showed the highest measured microbial activity (reduction of 1,200?nmol?INT?g(-1)?h(-1)), likely from a population adapted to environmental pollutants, rates that are much higher than measured in many uncontaminated soil and sediment systems. These data warrant further investigation into community structure at the genetic level and indicate potential for bioremediation by indigenous microbes.     

黄土丘陵沟壑区不同植被恢复格局下土壤微生物群落结构

针对典型黄土丘陵沟壑区陕西延安羊圈沟小流域坡面上单一刺槐林、单一撂荒草地以及林草搭配的草地-林地-草地及林地-草地-林地4种不同植被格局,利用磷脂脂肪酸(phospholipid fatty acid,PLFA)谱图分析法对土壤微生物群落结构进行监测研究,旨在揭示坡面上不同的植被恢复格局对土壤微生物群落结构的影响。研究发现4种不同植被格局下,2种林草搭配的植被格局磷脂脂肪酸的结构比较相似,与单一植被格局相比,表层土壤中表征真菌的特征脂肪酸所占的比例有所提高。主成分分析显示4种植被格局0—10 cm土壤微生物群落结构存在差异,差异主要存在于2种林草搭配的植被格局与2种单一的植被格局之间,其中草地-林地-草地的植被格局与刺槐林和撂荒草地之间土壤微生物群落结构的差异均达到了显著水平。不同微生物菌群的量在4种植被格局土壤间显著性差异主要存在于表层土壤中的细菌菌群和革兰氏阳性菌,革兰氏阴性菌和真菌在4种植被格局土壤之间无显著差异。总之,4种不同植被恢复格局的土壤微生物群落结构存在差异且差异主要存在于表层土壤,坡面上人工林的种植及林草搭配的恢复模式较直接撂荒更有利于提高微生物菌群的生物量。