多环芳烃污染土壤的植物与微生物修复研究进展

概括介绍了多环芳烃污染土壤的植物修复、微生物修复和植物 微生物联合修复的原理、优缺点、影响因素及国内外研究进展 ,并对生物修复的未来发展进行了展望     

微生物与重金属相互作用过程与机制研究进展

重金属污染对土壤、地下水和农作物等会产生重大影响,并通过生物链危害人体健康.微生物在环境中广泛存在,在矿物分解、元素释放、迁移、沉淀和再富集过程中起着重要作用,进一步发掘对不同重金属具有耐受性的特异性菌株,探究其对重金属的解毒和耐受性的机制,可更好地为微生物用于环境修复工作提供理论依据.综述了微生物与环境中重金属的相互作用过程与机制以及微生物在修复重金属污染中的应用,结果表明:①微生物自身生长过程中产生的大量氨基酸、蛋白质和多肽等物质可与重金属鳌合,促进重金属的溶解和吸附过程.②重金属对微生物产生毒性影响,微生物通过氧化还原、生物矿化和甲基化等作用改变重金属元素的化学形态,降低重金属的毒性.③微生物对重金属的修复效果与重金属的存在形态有关,在实际应用中可先将重金属元素转化为易于被微生物吸附的形态,再利用特异性菌株进行生物修复.④根际微生物对植物吸收重金属起着重要的调控作用,但植物根系分泌物和微生物的新陈代谢产物对重金属形态及生物有效性的协同拮抗作用机制及其微观的界面过程尚未明晰,有待进一步研究.      

电子供体刺激下厌氧微生物对1, 2-二氯乙烷的降解效果

通过添加电子供体进行原位生物刺激可有效降解地下水中的氯代烃,目前国内外常采用接种高效微生物的方法强化这一降解过程,鲜见仅利用实际污染场地含水层土著菌开展的生物降解试验.从北京市某氯代烃污染场地采集地下水样品,仅接种场地含水层沉积物,利用微宇宙实验体系,初步探讨了添加不同种类和质量浓度的电子供体对地下水中1,2-二氯乙烷的去除效果影响.结果表明:①同时添加初级生长基质和电子供体对反应体系进行生物刺激可显著降解地下水中的1,2-二氯乙烷.60 d后,添加1 g/L醋酸钠的反应体系中1,2-二氯乙烷的去除率最高,可达93.9%;添加1 g/L的乳酸钠反应体系次之,去除率为82.2%;添加1 g/L的乳酸的反应体系去除率最低,为61.8%.并且添加醋酸钠的试验体系可长时间维持中性pH及较低的氧化还原电位.②相同条件下,对同种电子供体来说,添加量为1 g/L的试验组中1,2-二氯乙烷的降解效果优于添加量为2 g/L的试验组,推测较高质量浓度的电子供体可对微生物的生命活动产生抑制.③对反应体系中间产物进行监测,仅监测到了乙烯的产生,表明在试验周期内无明显毒副产物积累,1,2-二氯乙烷的降解较为彻底.研究显示,醋酸钠为该试验体系中最适电子供体,添加适宜质量浓度醋酸钠对土著菌进行生物刺激可实现对1,2-二氯乙烷的绿色降解.      

基于iTRAQ技术荧蒽降解菌的比较蛋白质组学分析

提取荧蒽不同诱导时间的红球菌BAP-1蛋白,应用iTRAQ技术结合LC-MS/MS对差异蛋白进行聚类以及生物信息学分析,以研究荧蒽高效降解菌的蛋白功能调控机理.结果表明：共鉴定到796个差异蛋白（差异倍数为2）,其中表达上调的有613个,表达下调的有183个.3个比对组（3d/1d、6d/1d和8d/1d）共同差异表达蛋白为111个（上调56个,下调55个）.通过COG、GO富集和pathway富集分析后发现绝大部分差异蛋白参与代谢和能量产生过程.在荧蒽诱导下上调关键蛋白有细胞色素C、三磷酸腺苷合成酶、二磷酸核苷等激酶,还有一些结合蛋白、脱氢酶、核糖体蛋白和趋化性蛋白等;下调显著的是5-甲基四氢蝶酰三谷氨酸-同型半胱氨酸甲基转移酶.这些蛋白共同组成蛋白互作网络调控荧蒽降解菌的一系列生命活动.     

近海污染的生态修复技术研究进展

随着现代社会经济的快速发展,近岸海域污染已成为世界性难题,严重影响近海海洋生态系统.如何对受损海洋生态系统进行修复成为当前海洋环境科学的热点问题.本文结合国内外的研究进展,扼要阐述了海洋生态修复的基本原理;并按生态系统不同营养级——生产者（植物）、消费者（动物）和分解者（微生物）梳理了当前主要的近海污染生态修复技术及其研究现状;分析其在修复实践中可能存在的问题并提出进一步的研究方向.本文可为控制海洋污染,保护海洋生态系统,开展海洋生态修复理论与实践研究,以及制定海洋生态保护政策提供有益的参考.     

Indigenous Heavy Metal Multiresistant Microbiota of Las Catonas Stream

Las Catonas stream (Buenos Aires Metropolitan Area) receives a complex mixture of pollutants from point and diffuse sources because of the agricultural, industrial and urban land uses of its basin. Widespread detection of heavy metals exceeding aquatic life protection levels has occurred in monitoring reconnaissance studies in surface and pore water. As a result of the screening of Cu, Cd, Zn and Pb resistant/tolerant and culturable microbiota, B101N and 200H strains (Pseudomonas fluorescens or putida) were isolated and selected for further studies. They showed 65% Cd and 35% Zn extraction efficiency from aqueous phase. The potential use of these strains in wastewater treatment is currently investigated in order to contribute to decrease heavy metal pollution, a problem affecting every stream of Buenos Aires Metropolitan Area.     

Effect of expandable clays and cometabolism on PAH biodegradability

Pyrene and phenanthrene degradation was examined in both single and binary slurry systems for three different natural soils. It was found that the amount of total expandable clays (smectite and vermiculite) was in a good agreement with the achieved rate and extent of biodegradation. For instance, the intrinsic phenanthrene biodegradation rate was 626 microg/L/day for the soil with the largest expandable clay and 3203 microg/L/day for the soil with the least. Similarly, the smallest total pyrene biodegradation (65%) was found for the soil rich in expandable clays, compared to an 82% pyrene reduction in the soil that had the lowest amount. Mass transfer limitation after compound sorption to the clays was more pronounced for the more hydrophobic pyrene. In the presence of phenanthrene, total pyrene biodegradation increased by 2 to 7% due to cometabolism, while the total phenanthrene biodegradation was only enhanced by 0.5 to 5% in the binary system. This research demonstrated that expandable clays might govern the substrate availability to microorganisms and microbial accessibility to substrates. Therefore, the contribution of organic matter and expandable clays to sorption, desorption and biodegradation should be taken equally into account in order to better understand complex bioremediation issues.     

极端环境下的石油烃生物降解及其在生物修复中的应用

文章综合论述了微生物在高温、低温、高盐等极端条件下对石油烃的生物降解过程,研究了生物降解在生物修复中的应用效果。同时,还介绍了对于强酸、强碱及高压条件下石油烃生物降解的研究状况,论述了研究石油烃生物降解对开发和丰富微生物资源的重要性。     

Bacteria Degrading PCBs and CBs Isolated from Long-Term PCB Contaminated Soil

Bacteria able to degrade polychlorinated biphenyls (PCBs) and chlorobenzoic acids (CBs) were isolated from soil that had been contaminated with PCBs for 15–30 years. Contaminated soil in which PCB content ranged between 10–470 mg/kg was naturally vegetated with different plants including ash (Fraxinus excelsior), birch (Betula pendula), black locust (Robinia pseudoacacia), Austrian pine (Pinus nigra) and goat willow (Salix caprea) trees as well as a variety of grasses and forbs. Bacteria able to use biphenyl as a sole source of carbon and energy were found in the root zone of all plants, but occurred in the largest numbers beneath pine and black locust. Bacteria able to degrade chlorobenzoic acids were isolated from the same location contaminated with PCBs. Strains that were taxonomically identified by 16S rDNA as Pandoraea were able to use 2-CB, 3-CB, 2,3-CB, 2,5-CB as sole carbon sources, and the strain Arthrobacter utilised 4-CB.     

Bioremediation of Stranded Oil on an Arctic Shoreline

The application of slow-release and soluble fertilizers proved to be an effective and environmentally benign way of stimulating oil biodegradation on an Arctic shoreline. Fertilizer application to the surface of the beach delivered nutrients to the oiled sediment beneath the beach surface. There was no significant run-off of this fertilizer to either the nearshore water or to unfertilized plots, and there were no adverse toxicological effects of the fertilizer application. The fertilizer application was followed by an increase in oxygen consumption and carbon dioxide evolution from the beach, increased microbial biomass, and significantly greater biodegradation of oil on the plots that had received fertilizer. The rate of oil biodegradation was approximately doubled over the course of a year by fertilizer applications in the first two months after the spill.Simple test kits proved adequate to monitor the fertilizer-application process in the field in a time frame that would allow the application process to be fine-tuned during treatment on a real spill. Simple test kits and portable instrumentation were useful in demonstrating the initial success of the bioremediation strategy.