植物修复多氯联苯研究进展

综述了植物修复持久性有机污染物多氯联苯（PCBs）的研究进展,重点阐述了植物对PCBs的去除作用和机理,植物在从环境中去除PCBs的过程中,不仅仅是作为微生物降解的支持者,而且还作为积极的参与者对PCBs进行代谢：一方面植物通过根系从环境中吸收和积累PCBs,并将吸收的PCBs转化为非毒性的代谢产物累积于植物组织中;另一方面植物释放促进PCBs降解的酶直接降解PCBs,或释放根系分泌物,增加根际微生物的数量,提高其活性间接降解PCBs.文中对植物修复PCBs的影响因素如植物组织培养的类型、生物量、PCBs的初始浓度以及PCBs的类型、理化性质等进行了讨论.     

PCBs对红树林沉积物中微生物及酶活性的影响

研究了多氯联苯（PCBs）对沉积物及红树植物秋茄根区沉积物微生物及酶活性的影响。结果表明,种植秋茄可提高沉积物中细菌和放线菌的数量,但不能提高真菌的数量。PCBs处理可显著提高沉积物中细菌和放线菌的数量。土壤呼吸与微生物量具有相似的变化趋势。由于细菌在沉积物微生物中占有绝对的优势,因此细菌的数量是微生物多样性指数的决定性因素。与未种植红树植物的相比,种植沉积物微生物多样性指数相对较低,PCBs处理与对照相比,微生物多样性指数差异不显著。在试验过程中,未种植的PCBs处理组多酚氧化酶和过氧化物酶活性均高于对照组,表明这两种酶是沉积物PCBs污染的敏感指标,而这两种酶被报道在植物修复中与PCBs的降解有关。     

蔷薇类离体培养物降解多氯联苯

多氯联苯类(PCBs)物质是毒性很强的环境污染物。PCBs由于它的广泛存在、在被污染的食物链高层次上的富集以及在普通环境条件下的抗降解性而受到特别重视。已经证明,在植物-水-土壤系统中,PCBs可以被降解,但还不清楚PCBs在这类系统中的降解作用是由植物还是土壤微生物或两者共同代谢掉的。美国俄克拉何马大学的J.Fletcher及其同事和美国环境保护署已经证明:无菌条件下     

有机磷生物修复研究进展

目前,有机磷的生物修复还主要是微生物修复。但是植物修复更具优越性,因其花费更少、对环境更安全。然而植物对生长条件的要求相对较高,修复效率较低,应用还非常有限。本文综述了有机磷微生物修复和植物修复的研究进展,总结了已知的有机磷降解酶及其生物来源。结果表明,植物材料的筛选、土壤与OPs作用机理的研究、植物耐受和消除OPs的基因组学研究、植物-微生物联合降解体系的建立以及降解酶的植物根系分泌系统的利用是提高有机磷植物修复效率的重要途径。     

多氯联苯降解菌Burkholderia xenovorans LB400研究进展

Burkholderia xenovorans LB400是一株多氯联苯(polychlorinated biphenyls,PCBs)降解菌,可以氧化含有1?6个氯取代基的多氯联苯。近年来,由于其广泛的底物谱和优异的降解性能,菌株LB400已成为研究原核生物降解多氯联苯的生物化学和分子生物学方面的模式生物。目前关于PCBs的微生物降解研究已不再局限于对微生物资源的挖掘,而是更多地聚焦在LB400等降解菌的PCBs降解基因、降解酶的酶学特性以及酶的人工分子进化等方面。同时,LB400作为早期发现的降解菌,其对多氯联苯的降解途径、底物范围及相关机制也被广泛探讨;但是对于PCBs降解相关基因的调控研究较少。因此,本文以Burkholderia xenovorans LB400对多氯联苯降解为核心,通过综述其代谢途径、代谢相关基因和酶系以及降解应用等方面的研究进展,以期为深入探讨Burkholderia xenovorans LB400的应用以及进一步在遗传、分子和生化水平研究其他多氯联苯降解菌株提供借鉴。     

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.     

微生物降解石油污染物机制研究进展

石油污染是当前紧迫的水环境问题,研究石油污染物降解机制有助于探索石油污染修复技术路径。重点介绍了微生物降解石油污染物过程中的微生物种类、降解机制和反应机理,即具有代表性的细菌、真菌和藻类,石油烃的有氧降解(链烷烃、环烷烃和芳香烃)和厌氧降解(脱氢羟基化、延胡索酸盐加成)。并对微生物降解石油组分的影响因素进行了讨论,具体包括:烃类结构(支链多结构越复杂,越难降解)、微生物种类(混合菌的生化降解能力更强)、环境因子(pH、温度、盐度、含氧量和营养物质),进一步指出了生物修复技术应用于石油污染修复治理研究中的优缺点。此外,还对现有微生物降解技术的应用做了简要概述,归纳总结现有研究中存在的问题,尝试性的提出了今后生物降解石油污染物的研究重点,即生物降解石油的机制还需进一步明确,并重点分析了生物电化学方法在降解去除石油污染物方面可行性。综述石油烃生物降解机制和反应机理,以期为生物修复水体石油污染提供参考和借鉴作用。     

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。     

多环芳烃厌氧生物降解研究进展

多环芳烃（PAHs）是环境中广泛分布的一类持久性有机污染物,对生态环境和公众健康具有极大危害。微生物降解是环境中去除多环芳烃污染的有效途径,近年来PAHs厌氧生物降解研究逐渐取代好氧降解成为人们关注的重点。本文从PAHs厌氧生物降解的研究背景出发,从不同厌氧还原反应体系、厌氧降解微生物、PAHs厌氧生物转化途径等方面阐述了PAHs厌氧生物降解的研究概况,归纳了对PAHs厌氧生物降解有积极作用的影响因素,提出了PAHs厌氧降解研究目前存在的问题,并对该领域未来研究方向作了简述和展望。希望为多环芳烃厌氧生物降解与环境修复研究与实践提供参考。     

面向有机污染物消除的“微生物、植物、电”多效耦合作用机制及低能耗型修复技术

中欧合作项目"面向有机污染物消除的‘微生物、植物、电’多效耦合作用机制及低能耗型修复技术"是由中国国家自然科学基金委和欧盟共同资助的重大国际合作项目。该项目研究领域属于环境生物技术,研究团队包括5个中方单位和17个欧方单位,项目主要围绕新有机污染物的生物降解过程和机制、低能耗生物修复技术开展研究工作。项目执行2年来,在降解污染物的微生物资源、弱电介入增效生物降解和强化电子传递、微生物3D打印等方面取得了阶段性成果的同时,项目团队还开展了有效的交流和实质性合作。未来,项目团队将克服新冠疫情影响,强化中欧双方团队内部和团队之间的合作交流,全面实现项目科学目标,圆满完成国际合作任务。     

Temperature-induced difference in microbial characterizations accounts for the fluctuation of sequencing batch biofilm reactor performance

Biodegradation - Generally, the purification performance of bioreactors could be influenced by temperature variation via shaping different microbial communities. However, the underlying mechanisms...     

Growth kinetics of an indigenous mixed microbial consortium during phenol degradation in a batch reactor

Biodegradation of phenol by a mixed microbial culture, isolated from a sewage treatment plant, was investigated in batch shake flasks. A minimum concentration of 100 and a maximum of 800 mg 1(-1) of phenol in the media were adapted in the degradation study. The phenol degradation rate varied largely and was less than 10 mg l(-1)h(-1) at both extremes of the initial concentrations in the media. The degradation rate was maximum 15.7 mg l(-1)h(-1) at 400 mg l(-1) phenol. The culture followed substrate inhibition kinetics and the specific growth rate were fitted to Haldane and Han-Levenspiel models. Between the two models the Han-Levenspiel was found to be a better fit with a root mean square error of 0.0211. The biokinetics constants estimated using these models showed good potential of the mixed microbial culture in phenol degradation.     

植物-微生物联合修复毒死蜱污染的土壤

本试验以毒死蜱污染土壤为研究材料,利用降解菌DSP-A分别与高丹草、紫花苜蓿、多花黑麦草进行联合修复,探讨了植物-微生物联合修复毒死蜱污染土壤的效果,以及影响联合修复的因素,结果表明,植物．微生物联合修复的效果优于单一的植物修复及单一的微生物修复效果。与DSP—A菌群较合适的植物是高丹草,该组合对毒死蜱的降解率达到96．44％,其次是多花黑麦草。研究了微生物数量、植株密度以及土壤湿度对联合修复效果的影响,结果表明,DSP．A菌菌液稀释倍数越大,联合修复的效果越差。植株密度对联合修复的影响,主要表现为对植物根系生长的影响。植株密度越大,对生存环境的竞争越激烈,植物根系的生长越不好。除了紫花苜蓿外,高丹草和多花黑麦草根系的生长均受到影响。高丹草种植密度为12株／盆时,与DSP—A菌的联合修复效果最好,多花黑麦草则为10株／盆。土壤湿度是影响联合修复的重要因素,不仅影响植物的生长,对微生物的生长也有影响。土壤湿度过大,造成土壤的含氧量降低,不利于植物根系和好氧细菌的生长,从而影响土壤中农药的降解。土壤湿度过小,容易造成植株缺水,根系生长和微生物的生长。高丹草与DSP．A菌、多花黑麦草与DSP—A菌联合修复最适浇水量都为20mL／d,紫花苜蓿与DSP—A菌联合修复最适浇水量都为15mL／d。     

Biodegradation of polyalcohol ethoxylate by a wastewater microbial consortium

Polyalcohol ethoxylate (PAE), an anionic surfactant, is the primary component in most laundry and dish wash detergents and is therefore highly loaded in domestic wastewater. Its biodegradation results in the formation of several metabolites and the fate of these metabolites through wastewater treatment plants, graywater recycling processes, and in the environment must be clearly understood. Biodegradation pathways for PAE were investigated in this project with a municipal wastewater microbial consortium. A microtiter-based oxygen sensor system was utilized to determine the preferential use of potential biodegradation products. Results show that while polyethylene glycols (PEGs) were readily degraded by PAE acclimated microorganisms, most of the carboxylic acids tested were not degraded. Biodegradation of PEGs suggests that hydrophobe–hydrophile scission was the dominant pathway for PAE biodegradation in this wastewater community. Ethylene glycol (EG) and diethylene glycol (DEG) were not utilized by microbial populations capable of degrading higher molecular weight EGs. It is possible that EG and DEG may accumulate. The microtiter-based oxygen sensor system was successfully utilized to elucidate information on PAE biodegradation pathways and could be applied to study biodegradation pathways for other important contaminants.     

Effects of Plant Diversity,Functional Group Composition,and Fertilization on Soil Microbial Properties in Experimental Grassland

BackgroundLoss of biodiversity and increased nutrient inputs are two of the most crucial anthropogenic factors driving ecosystem change. Although both received considerable attention in previous studies, information on their interactive effects on ecosystem functioning is scarce. In particular, little is known on how soil biota and their functions are affected by combined changes in plant diversity and fertilization.Conclusions/SignificanceOur study highlights the role of plant species and functional group diversity as well as interactions between plant community composition and fertilizer application for soil microbial functions. Our results suggest soil microbial stoichiometry to be a powerful indicator of microbial functioning under N limited conditions. Although our results support the notion that plant diversity and fertilizer application independently affect microbial functioning, legume effects on microbial N limitation were superimposed by fertilization, indicating significant interactions between the functional composition of plant communities and nutrient inputs for soil processes.     

Relationships among amino acid sequences of animal,microbial and plant peroxidases

Summary Relationships among 18 peroxidases amino acid sequences of animal, microbial and plant origin were examined using optimum alignment of all pairwise sequence combinations to generate a total distance matrix. The matrix was used to cluster the sequences with complete linkage (farthest neighbour) procedures. Specific distances were calculated from the total distances matrix. The patterns of specific distances for each sequence were compared to evaluate the relationships between sequences, check their significance and construct subgroups of related sequences. The results were compared with those from clustering and its resultant dendrogram; good agreement was achieved. The 18 sequences fell into two principal groups, plant peroxidases and animal/microbial peroxidases. Within the plant peroxidases four subgroups were detected; the animal/microbial peroxidases formed a fifth subgroup. Profiles were constructed for the subgroups from lists of matching amino acids generated by the alignment calculations. Superimposed lists were realigned to recognise conserved areas and elements. Individual subgroup profiles for the plant peroxidases were then combined into a single profile which in turn was combined with profiles from the animal/microbial peroxidases. The final profile suggested that numerous sequence features (motifs) were common to peroxidases of widely different function and origins.     

可降解塑料的微生物降解研究进展

塑料材料的广泛使用给环境带了巨大的污染和处理压力,使用可降解塑料替代传统塑料是解决这一问题的重要途径。可降解塑料的生物降解是由相应的微生物和降解酶来完成的。综述了目前常见的生物降解塑料的微生物降解研究和进展情况,明确了微生物在可降解塑料生物降解中的重要性。     

Indirect effects of polycyclic aromatic hydrocarbon contamination on microbial communities in legume and grass rhizospheres

Background and aims

Biodegradation of polycyclic aromatic hydrocarbons (PAHs) is accelerated in the presence of plants, due to the stimulation of rhizosphere microbes by plant exudates (nonspecific enhancement). However, plants may also recruit specific microbial groups in response to PAH stress (specific enhancement). In this study, plant effects on the development of rhizosphere microbial communities in heterogeneously contaminated soils were assessed for three grasses (ryegrass, red fescue and Yorkshire fog) and four legumes (white clover, chickpea, subterranean clover and red lentil).

Methods

Plants were cultivated using a split-root model with their roots divided between two independent pots containing either uncontaminated soil or PAH-contaminated soil (pyrene or phenanthrene). Microbial community development in the two halves of the rhizosphere was assessed by T-RFLP (bacterial and fungal community) or DGGE (bacterial community), and by 16S rRNA gene tag-pyrosequencing.

Results

In legume rhizospheres, the microbial community structure in the uncontaminated part of the split-root model was significantly influenced by the presence of PAH-contamination in the other part of the root system (indirect effect), but this effect was not seen for grasses. In the contaminated rhizospheres, Verrucomicrobia and Actinobacteria showed increased populations, and there was a dramatic increase in Denitratisoma numbers, suggesting that this genus may be important in rhizoremediation processes.

Conclusion

Our results show that Trifolium and other legumes respond to PAH-contamination stress in a systemic manner, to influence the microbial diversity in their rhizospheres.     

Key players and team play: anaerobic microbial communities in hydrocarbon-contaminated aquifers

Biodegradation of anthropogenic pollutants in shallow aquifers is an important microbial ecosystem service which is mainly brought about by indigenous anaerobic microorganisms. For the management of contaminated sites, risk assessment and control of natural attenuation, the assessment of in situ biodegradation and the underlying microbial processes is essential. The development of novel molecular methods, “omics” approaches, and high-throughput techniques has revealed new insight into complex microbial communities and their functions in anoxic environmental systems. This review summarizes recent advances in the application of molecular methods to study anaerobic microbial communities in contaminated terrestrial subsurface ecosystems. We focus on current approaches to analyze composition, dynamics, and functional diversity of subsurface communities, to link identity to activity and metabolic function, and to identify the ecophysiological role of not yet cultured microbes and syntrophic consortia. We discuss recent molecular surveys of contaminated sites from an ecological viewpoint regarding degrader ecotypes, abiotic factors shaping anaerobic communities, and biotic interactions underpinning the importance of microbial cooperation for microbial ecosystem services such as contaminant degradation.