小黑麦对石油污染盐碱土壤细菌群落与石油烃降解的影响

为了研究小黑麦对石油污染盐碱土壤中的细菌群落与石油烃降解率的影响,采用高通量测序技术,设置0 g/kg,1 g/kg和5 g/kg三个石油浓度,以未种植小黑麦的土壤作为对照,对6组不同处理的盐碱土壤样品的细菌群落结构及其多样性进行测定,并分析土壤中的石油烃降解率。结果表明:在土壤石油浓度为1 g/kg和5 g/kg时,小黑麦根际土壤中的石油烃降解率相较对照组分别提高了36.67%和33.20%。从6个土壤样品中分别获得21398—27899条测序序列。在石油污染土壤中,小黑麦根际土壤的细菌群落多样性和丰度均大于对照组的土壤。同时,在"门","纲","属"的分类水平上,小黑麦根际土壤细菌群落中的一些根际细菌的相对丰度增加了,主要包括变形菌门(Proteobacteria)、酸杆菌门(Acidobacteria)、γ-变形菌纲(Gammaproteobacteria)、烷烃降解菌科-未命名菌属(Alcanivoracaceae_norank)、黄单胞菌属(Xanthomonas)、亚硝化单胞菌-不可培养菌属(Nitrosomonadaceae_unculture)等。有一些相对丰度增加的根际细菌是以石油及石油分解物为碳源的微生物。本研究证明种植小黑麦改变了石油污染盐碱土壤根际土壤细菌群落结构组成和多样性,促进了降解石油微生物群落的构建,显著提高了盐碱土壤石油污染的降解效果。研究结果为石油污染盐碱土壤的植物修复奠定了理论基础。     

杉木人工林土壤微生物群落结构特征

采用氯仿熏蒸法、稀释平板法和磷脂脂肪酸(phospholipid fatty acid,PLFA)方法,分析了常绿阔叶林转变成杉木人工林后土壤微生物种群数量和群落结构的变化特征.结果表明:常绿阔叶林转变为杉木人工林后,林地土壤的微生物生物量碳、可培养细菌和放线菌数降低.杉木人工林地总PLFAs、细菌PLFAs、真菌PLFAs比常绿阔叶林分别降低了49.4％、52.4％和46.6％,革兰氏阳性和阴性细菌PLFAs远低于常绿阔叶林.杉木人工林根际土壤微生物生物量碳、可培养细菌和放线菌数显著高于杉木人工林林地土壤,根际土壤中总PLFAs、细菌PLFAs、革兰氏阳性和阴性细菌PLFAs的含量也高于林地土壤,但真菌PLFAs和细菌PLFAs之比却低于林地土壤.对土壤微生物群落结构进行主成分分析发现,第1主成分和第2主成分共解释了土壤微生物群落结构变异的78.2％.表明常绿阔叶林与杉木人工林土壤的微生物群落结构间存在差异.     

高通量测序解析多环芳烃污染盐碱土壤翅碱蓬根际微生物群落多样性

【目的】以多环芳烃(PAHs)污染盐碱土壤为对象,分析比较翅碱蓬根际与非根际土壤细菌群落多样性,为植物-微生物联合修复PAHs污染盐碱土壤提供依据。【方法】在胜利油田油井附近采集翅碱蓬根际土壤和无翅碱蓬生长区域的裸地表层土壤,基于高通量测序技术分析样品中微生物群落结构,并进一步运用Real-time PCR解析土壤中PAHs双加氧酶基因丰度。【结果】翅碱蓬根际土壤盐含量为22.51 g/kg,明显低于裸地土壤的40.03 g/kg,土壤pH值差别不大,分别为8.20和8.22;根际土壤有机质和总氮含量分别为24.41 g/kg和1.59 g/kg,C/N值为15,裸地土壤有机质和总氮含量分别为18.80 g/kg和0.71 g/kg,C/N值为26;高通量测序得到根际和裸地土壤样品优质序列分别为53 854条和30 312条,在97%相似水平下,根际土壤样品所得OTU数、Chao 1指数和ACE指数分别为5 934、11 461和15 555,分别高于裸地土壤对应指数的值(4 262、8 262、11 186),序列分析结果显示,根际土壤包含细菌32门758属,多于裸地土样28门676属,翅碱蓬根际土壤群落结构多样性均高于裸地土壤;PAHs污染盐碱土壤中存在丰富的微生物资源,有Thioalkalispira、Halothiobacillus、Thiohalophilus等多种嗜盐碱或耐盐碱微生物,并在根际土壤中检测到了PAHs双加氧酶基因(PAH-RHDα)。【结论】Thioalkalispira、Halothiobacillus、Thiohalophilus等嗜盐碱或耐盐碱微生物是胜利油田PAHs污染盐碱土壤中的优势菌属;翅碱蓬能有效降低根际土壤盐含量并改善C/N值,增加微生物群落结构多样性,提高PAHs关键功能基因的丰度,有助于促进嗜盐碱PAHs降解微生物在PAHs污染盐碱土壤的生物修复中发挥作用。     

盐碱胁迫对小麦幼苗生长和根际细菌群落结构的影响

【背景】植物可通过改变根际微生物群落结构来减轻胁迫,但盐碱胁迫下小麦生长和根际细菌群落结构变化尚待明晰。【目的】明确盐碱胁迫下小麦幼苗生长及根际细菌群落结构变化。【方法】以添加NaCl和Na2CO3调节Hoagland营养液Na+浓度和pH来模拟盐碱胁迫,通过MiSeq高通量测序分析细菌群落结构。【结果】与无胁迫对照相比,单纯盐胁迫使小麦幼苗地上和地下部干重、叶绿素和根际土壤速效氮含量分别显著降低了25.0%、57.1%、21.2%和42.9%(P<0.05);小麦幼苗生长指标和根际土壤速效氮、速效磷、有机质含量及酶活性(除过氧化氢酶)随碱度升高而降低;所有处理的小麦幼苗根际优势菌门(丰度7.1%-71.5%)均为变形菌门(Proteobacteria)、放线菌门(Actinobacteria)和厚壁菌门(Firmicutes),优势属(丰度0.5%-5.1%)有肠杆菌属(Enterobacter)、嗜多甲基菌属(Methyloversatilis)、固氮菌属(Azotobacter)、假单胞菌属(Pseudomonas)和异根瘤菌属(Allorhizobium)。盐碱胁迫未显著...     

不同荒漠植物根际土壤微生物群落结构特征

于2015年7月在甘肃安西极旱荒漠国家级自然保护区采集膜果麻黄(Ephedra przewalskii)、红砂(Reaumuria songarica)、合头草(Sympegma regelii)、泡泡刺(Nitraria sphaerocarpa)和珍珠猪毛菜(Salsola passerina)5种典型荒漠植物根际土壤样品,利用磷脂脂肪酸(PLFA)法结合Sherlock微生物鉴定系统分析了土壤微生物群落结构。结果表明,5种荒漠植物根际土壤微生物磷脂脂肪酸种类和组成差异显著,其中表征革兰氏阳性菌的18:0 iso、16:0 iso和17:1 isoω9c分别为红砂、珍珠猪毛菜特有表征放线菌的18:1ω7c 10-methyl仅在珍珠猪毛菜根际存在。总PLFAs、真菌、放线菌和真菌/细菌在珍珠猪毛菜中显著最高,革兰氏阳性菌、革兰氏阴性菌在膜果麻黄和珍珠猪毛菜根际显著高于其他植物,AM真菌在合头草根际有最高值。结构方程模型分析表明,与植物相比,土壤因子对微生物群落结构影响更为显著,其中易提取球囊霉素对放线菌有显著影响,土壤碱解氮是革兰氏阳性菌和革兰氏阴性菌的主要影响因子。同时,土壤微生物群落结构可用于检测不同荒漠植物根际微环境土壤退化状况。     

凋落物管理对樟子松人工林土壤微生物群落结构的影响

采用磷脂脂肪酸法(PLFA)分析短期(18个月)凋落物管理对樟子松人工林土壤微生物群落结构的影响。结果表明,凋落物移除对土壤各类微生物的PLFAs均无显著影响,但凋落物加倍显著改变了土壤微生物群落结构。凋落物加倍显著提高了土壤PLFAs总量、革兰氏阳性细菌(G+)与革兰氏阴性细菌(G-)和原生动物PLFAs,但对真菌和放线菌PLFAs以及细菌/真菌值、G+/G-值影响不显著。凋落物加倍使土壤总PLFAs上升了82.4%,细菌PLFAs上升了93.9%。凋落物管理对樟子松人工林土壤微生物的Shannon多样性指数、Pielou均匀度指数和Simpson优势度指数均无显著影响。主成分分析表明,主成分1(89.83%)上得分系数较高的PLFAs多为细菌的特征PLFAs,主要有16:1ω5c、16:1ω7c、cy17:0ω7c、cy19:0ω7c、i14:0、i15:0。     

氮肥添加对高寒藏嵩草(Kobresia tibetica)沼泽化草甸和土壤微生物群落的影响

以藏嵩草沼泽化草甸为研究对象,利用磷脂脂肪酸(PLFA)技术,研究连续6年N素添加对地上植被群落数量特征、土壤微生物群落结构的影响。结果表明:①藏嵩草沼泽化草甸群落生物量、枯枝落叶对施肥处理无明显响应,且莎草科植物对土壤氮素的吸收和利用率较低。②施肥增加了0-10 cm土壤微生物类群PLFAs丰富度尤其细菌和革兰氏阳性菌PLFAs,降低了10-20 cm PLFAs丰富度;③磷脂脂肪酸饱和脂肪酸/单烯不饱和脂肪酸、细菌PLFAs/真菌PLFAs的比值随土壤层次增加而增加;④0-10 cm土层革兰氏阳性菌、真菌PLFAs含量与pH、土壤速效磷、速效氮、土壤有机质显著正相关(P0.05或P0.01);10-20 cm土层,细菌、革兰氏阳性菌、真菌和总PLFAs含量与土壤有机质含量显著正相关(P0.05或P0.01)。表明藏嵩草沼泽化草甸微生物PLFAs含量和丰富度对施肥的响应存在明显的土层梯度效应,土壤微生物PLFAs含量和丰富度主要受表层土壤初始养分含量的影响。     

广东省本地油茶和引种油茶根际土壤微生物群落特征

【背景】近年来,油茶低效林面积较大,根际土壤微生物影响林木抗性和生长,对林业可持续发展具有重要意义。【目的】了解广东省本地油茶和引种油茶根际土壤微生物群落特征。【方法】利用高通量测序分析油茶根际土壤微生物群落组成。【结果】油茶根际土壤细菌有26门77纲201目377科593属676种,真菌有14门50纲121目266科502属631种。油茶根际土壤中的优势细菌为酸杆菌门和变形菌门,优势真菌为子囊菌门和担子菌门。两种油茶根际土壤微生物组成差异显著,本地油茶根际土壤的细菌多样性显著高于引种油茶。在门水平上,脱硫杆菌门细菌和罗兹菌门、被孢霉门真菌的相对丰度在两种油茶间差异显著,Amorphotheca在本地油茶根际土壤中特异性富集。两种油茶根际土壤细菌碳代谢相对丰度差异显著,真菌以腐生营养型为主,其次为病理营养型和共生营养型。本地油茶根际土壤中显著富集土壤腐生菌,而共生营养型真菌(尤其是丛枝菌根真菌)相对丰度(6.43%)显著低于引种油茶中(21.83%)。此外,有机质和养分含量是影响油茶根际土壤微生物群落的关键因子。【结论】本地油茶和引种油茶根际土壤微生物群落组成和结构差异显著,Amorp...     

典型农田土壤中丛枝菌根真菌-根际细菌互作及与氮磷利用的关系

在农业生态系统中,土壤微生物是土壤-作物系统养分循环的重要驱动力,其中丛枝菌根真菌(Arbuscularmycorrhizalfungi,AMF)能够促进作物对养分的吸收,适应逆境胁迫。【目的】进一步揭示AMF和根际细菌群落的跨界网络互作,挖掘与作物氮磷利用显著相关的关键微生物类群,揭示关键类群的生态网络特征。【方法】利用Illumina测序技术对3种典型农田旱地土壤(黑土、潮土和红壤)中AMF和根际细菌群落结构进行分析;构建互作网络并利用偏冗余分析、相关性分析探究了与氮磷利用相关的潜在关键类群。【结果】3种土壤中AMF与根际细菌均以正相互作用为主。不同土壤中AMF与根际细菌互作关系差异明显,在红壤中跨界互作最为密切,其中球囊霉属真菌(Glomus)与根际细菌中的放线菌(Actinobacteria)和变形菌(Proteobacteria)之间的交互作用最多。而在黑土中主要体现为根际细菌的界内互作。与氮磷利用率显著相关的关键微生物类群主要属于球囊霉属真菌、放线菌和α变形菌。【结论】典型旱地土壤中AMF与根际细菌的正相互关系对作物氮磷利用有潜在促进作用,关键类群在有机质和养分贫乏的红壤中可能起到更重要的作用。     

转Bt+CpTI基因棉花对根际土壤细菌及氨氧化细菌数量的影响

转基因棉花对根际土壤微生物的影响在转基因作物风险评估中具有重要意义。【目的】通过研究转基因棉花根际微生物群落变化来评估转基因棉花的生态风险。【方法】以转Bt+CpTI基因抗虫棉(SGK321)及非转基因亲本棉花石远321(SY321)根际土壤总细菌和氨氧化细菌为研究对象,分别在种植前和棉花的不同生长时期(蕾期、花期、铃期和絮期)取样。采用微滴数码PCR方法对土壤中总细菌16S rRNA和氨氧化细菌的功能基因amoA基因进行定量分析。【结果】结果发现两种棉花根际土壤中的总细菌数量随棉花生长的不同时期没有显著差异。但是对氨氧化细菌的定量结果表明随棉花不同生长时期,两种棉花根际土壤中的氨氧化细菌数量均发生显著变化,但变化趋势不同:在蕾期,SY321和SGK321根际土壤中的氨氧化细菌数量分别增加了4倍和2倍;在花期,SY321根际氨氧化细菌与蕾期相比显著降低至5.96×105copies/g dry soil,而SGK321根际氨氧化细菌则显著增加至1.25×106copies/g dry soil;在铃期,SY321根际氨氧化细菌显著增加至1.49×106copies/g dry soil,而SGK321根际土壤中氨氧化细菌数量没有发生显著变化;絮期两者均表现为降低,但差异显著。与非转基因棉花相比,转基因棉花根际土壤中的氨氧化细菌变化相对较为平缓。【结论】这表明氨氧化细菌数量既受棉花生长时期的影响,同时也受转基因棉花的影响,转基因棉花通过影响氨氧化细菌的数量减缓氨的转化速度,这在一定程度上有利于植物生长。     

Allocation of energy use in petroleum refineries to petroleum products

Aim, Scope, and Background  Studies to evaluate the energy and emission impacts of vehicle/fuel systems have to address allocation of the energy use and emissions associated with petroleum refineries to various petroleum products because refineries produce multiple products. The allocation is needed in evaluating energy and emission effects of individual transportation fuels. Allocation methods used so far for petroleum-based fuels (e.g., gasoline, diesel, and liquefied petroleum gas [LPG]) are based primarily on mass, energy content, or market value shares of individual fuels from a given refinery. The aggregate approach at the refinery level is unable to account for the energy use and emission differences associated with producing individual fuels at the next sub-level: individual refining processes within a refinery. The approach ignores the fact that different refinery products go through different processes within a refinery. Allocation at the subprocess level (i.e., the refining process level) instead of at the aggregate process level (i.e., the refinery level) is advocated by the International Standard Organization. In this study, we seek a means of allocating total refinery energy use among various refinery products at the level of individual refinery processes. Main Features  We present a petroleum refinery-process-based approach to allocating energy use in a petroleum refinery to petroleum refinery products according to mass, energy content, and market value share of final and intermediate petroleum products as they flow through refining processes within a refinery. The approach is based on energy and mass balance among refining processes within a petroleum refinery. By using published energy and mass balance data for a simplified U.S. refinery, we developed a methodology and used it to allocate total energy use within a refinery to various petroleum products. The approach accounts for energy use during individual refining processes by tracking product stream mass and energy use within a refinery. The energy use associated with an individual refining process is then distributed to product streams by using the mass, energy content, or market value share of each product stream as the weighting factors. Results  The results from this study reveal that product-specific energy use based on the refinery process-level allocation differs considerably from that based on the refinery-level allocation. We calculated well-to-pump total energy use and greenhouse gas (GHG) emissions for gasoline, diesel, LPG, and naphtha with the refinery process-based allocation approach. For gasoline, the efficiency estimated from the refinery-level allocation underestimates gasoline energy use, relative to the process-level based gasoline efficiency. For diesel fuel, the well-to-pump energy use for the process-level allocations with the mass- and energy-content-based weighting factors is smaller than that predicted with the refinery-level allocations. However, the process-level allocation with the market-value-based weighting factors has results very close to those obtained by using the refinery-level allocations. For LPG, the refinery-level allocation significantly overestimates LPG energy use. For naphtha, the refinery-level allocation overestimates naphtha energy use. The GHG emission patterns for each of the fuels are similar to those of energy use. Conclusions  We presented a refining-process-level-based method that can be used to allocate energy use of individual refining processes to refinery products. The process-level-based method captures process-dependent characteristics of fuel production within a petroleum refinery. The method starts with the mass and energy flow chart of a refinery, tracks energy use by individual refining processes, and distributes energy use of a given refining process to products from the process. In allocating energy use to refinery products, the allocation method could rely on product mass, product energy contents, or product market values as weighting factors. While the mass- and energy-content-based allocation methods provide an engineering perspective of energy allocation within a refinery, the market-value-based allocation method provides an economic perspective. The results from this study show that energy allocations at the aggregate refinery level and at the refining process level could make a difference in evaluating the energy use and emissions associated with individual petroleum products. Furthermore, for the refining-process-level allocation method, use of mass — energy content- or market value share-based weighting factors could lead to different results for diesel fuels, LPG, and naphtha. We suggest that, when possible, energy use allocations should be made at the lowest subprocess level — a confirmation of the recommendation by the International Standard Organization for life cycle analyses. Outlook  The allocation of energy use in petroleum refineries at the refining process level in this study follows the recommendation of ISO 14041 that allocations should be accomplished at the subprocess level when possible. We developed a method in this study that can be readily adapted for refineries in which process-level energy and mass balance data are available. The process-level allocation helps reveal some additional energy and emission burdens associated with certain refinery products that are otherwise overlooked with the refinery-level allocation. When possible, process-level allocation should be used in life-cycle analyses.     

Compared the physiological response of two petroleum tolerant-contrasting plants to petroleum stress

Petroleum not only benefits the world economy but also contaminates the soil. In order to select the plants tolerant to petroleum, the physiological response of two petroleum tolerant-contrasting plants, Mirabilis jalapa and Orychophragmus violace, were investigated in variation of petroleum-contaminated soils (0, 5, 10, 20, and 40 g petroleum per kg soil) for 120 d. Petroleum degradation rate, seeds germination rate, free proline, and superoxide dismutase and peroxidase activities of M. jalapa were higher than that of O. violace under petroleum stress. However, the decrease rate of soluble protein, plant height, chlorophyll, and root fresh weight was greater in O. violace as compared to M. jalapa. Pearson correlation coefficient analysis was conducted, which indicated that the higher tolerance of M. jalapa was correlated with the higher level of free proline and antioxidative enzyme activities. Besides, the 10 g petroleum per kg soil may be appropriate for petroleum-tolerant plants selection, in which petroleum significantly restrain growth in O. violace but not in M. jalapa.     

Microbiology of petroleum reservoirs

Although the importance of bacterial activities in oil reservoirs was recognized a long time ago, our knowledge of the nature and diversity of bacteria growing in these ecosystems is still poor, and their metabolic activities in situ largely ignored. This paper reviews our current knowledge about these bacteria and emphasises the importance of the petrochemical and geochemical characteristics in understanding their presence in such environments.     

Selection of microorganisms capable of degrading petroleum and petroleum products at decreased temperatures

Of 150 cultures capable of degrading petroleum at +6 degrees C, 40 strains growing in the liquid mineral nutrient medium containing petroleum (2%) as a sole source of carbon were selected. Of them, 13 cultures displaying a petroleum degradation rate exceeding 25% were selected. Abilities of these cultures and their associations to utilize fuel oil and its components--oils and benzene resins--were studied. The culture exhibiting degradation rates of fuel oil, its oils, benzene resins, and petroleum amounting to 17, 26, 10, and 51%, respectively, was selected. This culture can be used for cleanup of petroleum pollution under cold climatic conditions.     

Plant biotests of soil and water, polluted with petroleum and petroleum products

Reactiona of higher plants (mustard, oat, rye, salad, dill and barley) and microalgae (Euglena gracilis) on the contamination of soil and water with petroleum and oil products was studied. The germination of seeds was analyzed. The length of sprouts, dry biomass and length of plant roots, as well as the optical density of micro-algal broth culture were determined. Negative effects of soil and water contamination with petroleum and oil products on plant and microalgal parameters examined was shown. After biological destruction of contaminants by an association of destructor strains (Acinetobacter sp., Mycobacterium flavescens and Rhodoccocus sp.), the toxicity of contaminated mediums decreased. The data suggest that the integral toxicity of soil and water contaminated with petroleum and oil products and toxicity change during biodestruction of these pollutants can be analyzed by using plant test organisms.     

石油微生物脱硫的研究进展

随着世界各国环保意识的不断提高及对油品含硫量标准规定日趋严格,生物脱硫技术已成为石油脱硫领域内的研究热点之一。本文主要从生物脱硫分子生物学和嗜热脱硫细菌两个方面介绍了国内外近年来的研究进展。     

Biotechnology of petroleum pollutant biodegradation

Procedures designed to meet the physiological needs of petroleum hydrocarbon (PHC) degrading microorganisms are useful in mitigating environmental damage caused by marine and terrestrial PHC spills. By similar approaches, soil can be utilized as a cost-effective biological incinerator for hazardous PHC wastes. Physiological ecology needs to complement genetic engineering efforts for an effective attack on environmental pollution problems.