嗜盐微生物在环境修复中的研究进展

人类活动产生的污染物,使一些天然盐环境遭受不同程度的污染,或者使环境受到污染物与高盐的双重污染。在高盐条件下,非嗜盐微生物的代谢会受到抑制,其生物修复效率明显降低,甚至丧失修复能力。嗜盐微生物则能够在高盐环境中栖息繁殖,凸显其修复被污染高盐环境的生物学效率和广阔的应用前景。就嗜盐微生物降解石油烃、芳香烃衍生物和有机磷等污染物的研究进展进行了综述和讨论。     

环境中的微生物与微生物在环境中的作用

环境微生物学是一门研究微生物与其生活环境之间相互作用的科学,主要包括环境中的微生物和微生物在环境中的作用两大研究领域。《微生物学通报》本期推出的“环境微生物学主题刊”报道了研究报告21篇,内容涵盖环境微生物学研究前沿、环境微生物生态学及生物修复、环境微生物资源的发掘与利用、环境微生物生理学及生物制剂、环境污染修复与微生物多样性等领域,希望该主题刊的出版有助于促进我国环境微生物学领域的学术交流,推动我国环境微生物学学科的发展。     

微生物细胞表面展示技术在污染环境生物修复中的应用及展望

伴随着人口增长,工业化和城市化的进程,无机物和有机物引起的环境污染一直在稳定的持续增长。无机物和有机物污染给生物多样性,公众健康和生态系统带来的整体性的损害促使科学家们寻求有效的方法冶理污染。微生物技术应用于污染环境中外源性化学物质的降解和重金属的生物转化受到越来越广泛的关注。在过去的几年里,生物修复技术发生了巨大的变化,     

环境修复成为我国微生物研究的热点领域

2011年本刊发表论文的情况显示,环境微生物方面的研究工作独占鳌头,共发表31篇论文(不包括第4期\"环境微生物专刊\"),排名第二的农业微生物有27篇,工业微生物以25篇位列第三。值得注意的是,有关\"环境修复\"的文章有15篇,占环境微生物栏目的一半。在过去的一年里,我国环境微生物学同行在相关     

铁、锰等金属元素的微生物还原及其在环境生物修复中的意义

讨论了土壤及水体环境中Fe、Mn、U、Se等金属元素的还原,并对还原不同金属的微生物及其对各金属的酶促和非酶促还原机制进行了综述,同时就不同微生物还原各金属在治理环境污染方面的意义进行了概述。     

基于分子生物学的微生物修复技术在石油污染环境中的应用

日益增长的人类活动和工业生产带来的石油污染已成为严重的环境问题。微生物修复技术绿色环保,在石油污染修复中备受关注。分子生物学技术的应用使微生物修复技术发生了迅猛变革,并为高效降解菌剂的开发提供了资源,但目前还存在物种注释结果不够全面和精确、检测灵敏度有限等缺点。其他微生物修复技术在提高石油污染物的降解效率以及减少其对环境的危害等方面也具有相当大的潜力,特别是生物表面活性剂和生物刺激剂,修复周期较短,修复成本相对较低,在未来可以大规模应用。另外,分子生物学与其他微生物修复技术的结合成为降解石油污染物的有效工具。本文总结了分子生物学手段在石油污染环境中的应用,梳理了近年来微生物修复石油污染方法的研究进展,讨论了现有微生物修复技术的修复效果,并对未来微生物修复技术的发展方向进行了展望。     

微生物复合菌剂在西北典型煤矿破损生态区修复中的应用

【背景】 煤炭作为重要的能源物质,在生产活动中需求量巨大,但长期的煤炭开采会对矿区生态环境带来极大破坏。微生物修复作为一种对环境友好、操作简单、经济成本低的修复方式,在煤矿区生态系统恢复中有广泛的应用前景。【目的】 利用微生物复合菌剂对煤矿区排土场地进行修复。通过微生物的代谢活动以及与植物根系的相互作用,实现修复煤矿破碎生态环境的目的。【方法】 借助16S rRNA基因高通量测序技术对修复场地微生物群落结构进行分析。通过监测试验场地土壤营养成分、重金属含量以及场地荞麦植株生长状况,评价了微生物修复效果,并初步探究了微生物所发挥的功能。【结果】 试验场地中存在有多种具有修复能力的菌种,微生物菌剂的加入降低了试验场地微生物多样性,但对土著微生物群落结构的影响较小。经过150 d的现场修复,场地有机质含量提高70%、总氮含量提升20%、总钾含量提升48.4%。速效氮、磷、钾也分别提升40%、26.8%和24.2%,土壤肥力得到显著恢复。场地有机质、速效磷和速效钾含量在修复期内呈现出增长趋势,表明功能微生物持续为植物生长提供高效的营养物质。场地砷含量降低49%,铜含量降低41%,表明微生物对场地(类)重金属起到了修复作用。微生物通过促进植株根系生长,提高了植株对营养物质的吸收和利用,场地荞麦株高提高30%,干重提升100%,粗蛋白含量提高22.4%。【结论】 微生物菌剂显著提高了试验场地的土壤肥力,抑制了土壤重金属毒害作用,并有效地促进了场地经济作物的生长。微生物修复在煤矿区破损生态系统的恢复上具有巨大的应用价值。     

生防促生微生物在我国农业微生物研究中的位置

2012年,有关农业微生物领域的论文本刊发表了20篇,其中生防促生微生物方面的工作就有10篇.就本刊数据而言,体现了生防促生微生物的研究在相关领域的重要位置.刘晓云等[1]采用BOX分子标记技术筛选南苜蓿高效根瘤菌菌株;谢宗华、王海华等,王彦杰、左豫虎等,陈波、杜秉海等分别筛选和鉴定了一株水稻纹枯菌拮抗细菌[2],一株表面活性剂产生菌[3]以及樱桃根际促生细菌[4].周定中、张吉斌等开展了黑水虻肠道细菌抗菌筛选并鉴定了相关活性分子[5];殷幼平、王中康等分离鉴定了柑橘黄龙病隐症寄主九里香内生细菌[6].     

基因芯片技术在环境微生物群落研究中的应用

基因芯片技术作为一种快速、敏感、高通量的检测技术,近几年来在环境微生物群落研究中的应用越来越广泛并且得到充分的发展.它不仅可以研究环境微生物群落的微生物分布、种类、功能、动力学变化,还能分析环境污染等环境因素改变对其微生物生态的影响.本文按照基因芯片探针的设计方法,将环境样品群落研究基因芯片分为系统寡核苷酸芯片、功能基因芯片、群落基因组芯片、宏基因组芯片,并简要综述了该技术在活性污泥、土壤、水等环境样品微生物群落研究上的应用,最后,本文展望了该技术的研究方向和在寻找不同环境微生物群落之间差异微生物、差异基因或差异表达基因研究中的应用前景.     

生物信息学及其在环境微生物研究中的应用

生物信息学的快速发展,推动了微生物信息学的建立。模式微生物基因组学的研究,极大地丰富了生物信息学的内容。微生物结构基因组学和功能基因组学研究试图揭示基因结构与功能的内在联系,绘制出基因调控网络图。基因组功能注释是功能基因组学研究的主要目的。基因芯片技术的运用,成为环境微生物生态研究和功能酶基因定位的有力工具。生物信息学为环境微生物的研究和发展提供了一个崭新的信息平台和技术手段。介绍了一些相关数据库和专业网站。     

海洋石油污染物的微生物降解与生物修复

石油是海洋环境的主要污染物 ,已经对海洋及近岸环境造成了严重的危害。微生物降解是海洋石油污染去除的主要途径。海洋石油污染物的微生物降解受石油组分与理化性质、环境条件以及微生物群落组成等多方面因素的制约 ,N和P营养的缺乏是海洋石油污染物生物降解的主要限制因子。在生物降解研究基础上发展起来的生物修复技术在海洋石油污染治理中发展潜力巨大 ,并且取得了一系列成果。介绍了海洋中石油污染物的来源、转化过程、降解机理、影响生物降解因素及生物修复技术等方面内容 ,强调了生物修复技术在治理海洋石油污染环境中的优势和重要性 ,指出目前生物修复技术存在的问题。     

In situ bioremediation of contaminated aquifers and subsurface soils

Bioremediation, the use of microorganisms to detoxify and degrade hazardous wastes, is an emerging in situ treatment technology for the remediation of contaminated aquifers and subsurface soils. This technology depends upon the alteration of the physical/chemical conditions in the subsurface environment to optimize microbiological activity. As such, successful bioremediation depends not only upon an understanding of microbial degradation processes, but also upon an understanding of the complex interactions that occur between the contaminants, the subsurface environment, and the indigenous microbial populations at each site. At present, these interactions are poorly understood. Site‐specific evaluation and design therefore are essential for bioremediation. In this paper, we review microbiological, hydrological, and geochemical factors that should be considered in evaluating the appropriateness of bioremediation for hazardous waste‐contaminated aquifers and subsurface soils.     

Microbial community dynamics and evaluation of bioremediation strategies in oil-impacted salt marsh sediment microcosms

Microbial community dynamics in wetlands microcosms emended with commercial products (surfactant, a biological agent, and nutrients) designed to enhance bioremediation was followed for 3 months. The effectiveness of enhanced degradation was assessed by determining residual concentrations of individual petroleum hydrocarbons by GC/MS. The size and composition of the sediment microbial community was assessed using a variety of indices, including bacterial plate counts, MPNs, and DNA hybridizations with domain- and group-specific oligonucleotide probes. The addition of inorganic nutrients was the most effective treatment for the enhancement of oil degradation, resulting in marked degradation of petroleum alkanes and a lesser extent of degradation of aromatic oil constituents. The enhanced degradation was associated with increases in the amount of extractable microbial DNA and Streptomyces in the sediment, although not with increased viable counts (plate counts, MPN). Bacteria introduced with one of the proprietary products were still detected in the microcosms after 3 months, but were not a major quantitative constituent of the community. The biological product enhanced oil degradation relative to the control, but to a lesser extent than the nutrient additions alone. In contrast, application of the surfactant to the oil-impacted sediment decreased oil degradation. Journal of Industrial Microbiology & Biotechnology (2001) 27, 72–79. Received 18 March 2001/ Accepted in revised form 09 June 2001     

Bacterial biofilms and quorum sensing: fidelity in bioremediation technology

Increased contamination of the environment with toxic pollutants has paved the way for efficient strategies which can be implemented for environmental restoration. The major problem with conventional methods used for cleaning of pollutants is inefficiency and high economic costs. Bioremediation is a growing technology having advanced potential of cleaning pollutants. Biofilm formed by various micro-organisms potentially provide a suitable microenvironment for efficient bioremediation processes. High cell density and stress resistance properties of the biofilm environment provide opportunities for efficient metabolism of number of hydrophobic and toxic compounds. Bacterial biofilm formation is often regulated by quorum sensing (QS) which is a population density-based cell–cell communication process via signaling molecules. Numerous signaling molecules such as acyl homoserine lactones, peptides, autoinducer-2, diffusion signaling factors, and α-hydroxyketones have been studied in bacteria. Genetic alteration of QS machinery can be useful to modulate vital characters valuable for environmental applications such as biofilm formation, biosurfactant production, exopolysaccharide synthesis, horizontal gene transfer, catabolic gene expression, motility, and chemotaxis. These qualities are imperative for bacteria during degradation or detoxification of any pollutant. QS signals can be used for the fabrication of engineered biofilms with enhanced degradation kinetics. This review discusses the connection between QS and biofilm formation by bacteria in relation to bioremediation technology.     

Biotechnological potential of microbial consortia and future perspectives

Design of a microbial consortium is a newly emerging field that enables researchers to extend the frontiers of biotechnology from a pure culture to mixed cultures. A microbial consortium enables microbes to use a broad range of carbon sources. It provides microbes with robustness in response to environmental stress factors. Microbes in a consortium can perform complex functions that are impossible for a single organism. With advancement of technology, it is now possible to understand microbial interaction mechanism and construct consortia. Microbial consortia can be classified in terms of their construction, modes of interaction, and functions. Here we discuss different trends in the study of microbial functions and interactions, including single-cell genomics (SCG), microfluidics, fluorescent imaging, and membrane separation. Community profile studies using polymerase chain-reaction denaturing gradient gel electrophoresis (PCR-DGGE), amplified ribosomal DNA restriction analysis (ARDRA), and terminal restriction fragment-length polymorphism (T-RFLP) are also reviewed. We also provide a few examples of their possible applications in areas of biopolymers, bioenergy, biochemicals, and bioremediation.     

Nonreductive Biomineralization of Uranium(VI) Phosphate Via Microbial Phosphatase Activity in Anaerobic Conditions

The remediation of uranium from soils and groundwater at Department of Energy (DOE) sites across the United States represents a major environmental issue, and bioremediation has exhibited great potential as a strategy to immobilize U in the subsurface. The bioreduction of U(VI) to insoluble U(IV) uraninite has been proposed to be an effective bioremediation process in anaerobic conditions. However, high concentrations of nitrate and low pH found in some contaminated areas have been shown to limit the efficiency of microbial reduction of uranium. In the present study, nonreductive uranium biomineralization promoted by microbial phosphatase activity was investigated in anaerobic conditions in the presence of high nitrate and low pH as an alternative approach to the bioreduction of U(VI). A facultative anaerobe, Rahnella sp. Y9602, isolated from soils at DOE's Oak Ridge Field Research Center (ORFRC), was able to respire anaerobically on nitrate as a terminal electron acceptor in the presence of glycerol-3-phosphate (G3P) as the sole carbon and phosphorus source and hydrolyzed sufficient phosphate to precipitate 95% total uranium after 120 hours in synthetic groundwater at pH 5.5. Synchrotron X-ray diffraction and X-ray absorption spectroscopy identified the mineral formed as chernikovite, a U(VI) autunite-type mineral. The results of this study suggest that in contaminated subsurfaces, such as at the ORFRC, where high concentrations of nitrate and low pH may limit uranium bioreduction, the biomineralization of U(VI) phosphate minerals may be a more attractive approach for in situ remediation providing that a source of organophosphate is supplied for bioremediation.     

The role of microbial reductive dechlorination of TCE at a phytoremediation site

In April 1996, a phytoremediation field demonstration site at the Naval Air Station, Fort Worth, Texas, was developed to remediate shallow oxic ground water (< 3.7 m deep) contaminated with chlorinated ethenes. Microbial populations were sampled in February and June 1998. The populations under the newly planted cottonwood trees had not yet matured to an anaerobic community that could dechlorinate trichloroethene (TCE) to cis-1,2-dichloroethene (DCE); however, the microbial population under a mature (approximately 22-year-old) cottonwood tree about 30 m southwest of the plantings had a mature anaerobic population capable of dechlorinating TCE to DCE, and DCE to vinyl chloride (VC). Oxygen-free sediment incubations with contaminated groundwater also demonstrated that resident microorganisms were capable of the dechlorination of TCE to DCE. This suggests that a sufficient amount of organic material is present for microbial dechlorination in aquifer microniches where dissolved O2 concentrations are low. Phenol, benzoic acid, acetic acid, and a cyclic hydrocarbon, compounds consistent with the degradation of root exudates and complex aromatic compounds, were identified by gas chromatography/mass spectrometry (GC/MS) in sediment samples under the mature cottonwood tree. Elsewhere at the site, transpiration and degradation by the cottonwood trees appears to be responsible for loss of chlorinated ethenes.     

Assessment of the microbial potential for nitrate-enhanced bioremediation of a JP-4 fuel-contaminated aquifer

A site that was contaminated with JP-4 jet fuel was characterized microbiologically to assess the feasibility of nitrate-enhanced bioremediation. The results of microcosm studies indicated that the mean pseudo zero-order rate constants for alkylbenzene biodegradation and NO₃ ⁻-N removal were 1.2 and 2.4 mg L⁻¹ per day, respectively. Several alkylbenzenes were removed to a greater extent in samples contaminated with residual JP-4 than in unexposed samples and samples downgradient of the spill; benzene was recalcitrant in all samples. Numbers of total heterotrophs, JP-4-degraders, oligotrophs, total denitrifiers, denitrifiers growing in the presence of JP-4, estimates of cell number by analysis of phospholipid fatty acids, direct counts and aerobic and anaerobic protozoa were determined; however, numbers of microorganisms were not reliable predictors of alkylbenzene biodegradation activity. The presence of aerobic and anaerobic protozoa suggests that protozoa may be active under a variety of different electron acceptor conditions. The results of the characterization study indicated that the site was amenable to nitrate-enhanced bioremediation. Received 12 March 1996/ Accepted in revised form 17 September 1996     

Degradation of biphenyl by methanogenic microbial consortium

Biphenyl was readily degraded and mineralized to CO₂ and CH₄ by a PCB-dechlorinating anaerobic microbial consortium. Degradation occurred when biphenyl was supplied as a sole source of carbon or as a co-metabolic substrate together with glucose and methanol. p-Cresol was detected and confirmed by mass spectroscopy as a transient intermediate. Production of ¹⁴ C-CO₂ and ¹⁴C-CH₄ from ¹⁴C-biphenyl was observed in the approximate ratio of 1:2. The results indicated the existence of novel pathways for biphenyl degradation in a natural anaerobic microbial community.