寒区降解多环芳烃耐冷菌株的分离鉴定及特性

多环芳烃（Polycyclic Aromatic Hydrocarbons,PAHs）是土壤中一种典型的持久性有机污染物。典型寒区东北地区因农业投入品不合理使用、污灌等造成农田土壤中含有大量致癌、致畸与致突变的多环芳烃,针对寒区气候特征致使农田中微生物降解多环芳烃效果不佳,难以改善农田土壤环境并降低食品风险的关键问题,基于目前常用商品化的降解微生物多来自于温暖地区,且难以适应寒区气候的特性,该研究以PAHs典型污染物-菲（PHE）为研究底物,驯化温度15 ℃,筛选分离出适应寒区低温环境的7株菌。经鉴定及降解性能研究,筛选了3株在温度20 ℃、接种量5%、pH值为8、底物浓度500 mg/L,以及外源物质腐殖酸的促进的条件下PHE降解率达到80%的高效降解耐冷菌。以上3株菌两两之间与三者组合均无拮抗关系。对菌株进行碳源的广谱性分析,菌株对2-5环多环芳烃降解率可达15%～85%之间,在将菌株应用至20 ℃土壤环境时,60 d可降解土壤中75%的PHE。该耐冷菌群适应条件符合寒区农田土壤实际环境,研究结果对黑土地区土壤多环芳烃污染的微生物修复提供了一定的基础资料。     

鞘氨醇单胞菌对土壤中溴氨酸降解作用的研究

采用室内培养方法，研究了溴氨酸降解菌株——鞘氨醇单胞菌(Sphingomonas sp．)N1对土壤中溴氨酸的降解作用。结果表明，N1对土壤中溴氨酸的降解行为遵循二级反应动力学方程；高浓度的溴氨酸对N1菌有抑制作用；增大接种量能加快溴氨酸在土壤中的降解速率；N1菌株在土壤中降解溴氨酸的最适温度是30℃，最适pH是7．0；高温和偏碱性环境都会使N1菌株对溴氨酸的降解产生抑制作用。     

均匀电场下两株多环芳烃降解菌在土壤中的迁移及电动注入

采用电动注入装置,研究了枯草芽孢杆菌和白腐真菌在均匀电场作用下在土壤中的迁移特征,以及这两种微生物电动注入的效果.结果表明,枯草芽孢杆菌和白腐真菌可通过电泳和电渗两种作用在电场下迁移,电泳起主导作用,微生物向阳极迁移为主.在所研究土壤中,微生物的迁移速率分别为:枯草芽孢杆菌13.5 cm·d-1,白腐真菌18.0cm·...     

Prospecting microbial biofilms as climate smart strategies for improving plant and soil health: A review

Microbes and their products play key roles in complementing chemical fertilizers and plant protection chemicals by eliciting defence mechanisms in crop plants, thereby providing immunity and resistance against diverse stresses. Among the different environmental technologies used to mitigate climate change,several microbiological interventions are promising, among which biofilms, both naturally-existing and laboratory-developed, and their application have gained momentum recently. Microbial biofi...     

土著原油降解真菌的筛选及其降解效果

[目的]筛选土著原油降解真菌,研究其与植物联合修复原油污染的效果。[方法]从大庆长期原油污染的土壤中分离出原油降解真菌,通过菌落、菌丝形态及rDNA-ITS序列比对,确定种属,并且研究目标菌株在液体培养条件下单独接种于油污土壤和与玉米混合接种对土壤中总石油烃的降解效果。[结果]分离出的4种真菌分别为以木霉菌、尖孢镰刀菌、禾生小从壳和玉米赤霉,分别命名为x3、x5、x7和x9,4种真菌在3种接种条件下均表现出高效的石油烃降解率。但是,4种菌株在液体培养条件下降解率高于土壤中的,其中x9号真菌在与玉米混合接种后达到最大降解率78.01%,并在玉米根系发现明显的根瘤。[结论]真菌与植物联合修复土壤污染物是一种长期有效的、有利于土壤生境恢复的治理方法之一。     

我国赤潮频发现象分析与海藻栽培生物修复作用

In this paper, the history, main events and present status of red tide (HAB, harmful algal blooms) along China coast in recent years were reviewed and presented. It showed that the HAB's frequency and scale, number of HAB spec ies, percentage of toxic HAB events and the degree of damages to marine environment and economy have sharply increased in China since 1960's. Eutrophication was key factor for high occurrence of red tide. In this paper, main causes of frequent HAB occurrence along China coast was discussed. Many factors might influence the occurrence of red tide, which included weather, climate, coastal current, tidal current, water temperature, salinity, hydrodynamic and nutrient conditions, trace metals and the variation of biological environment. Numerous evidences from all over the world revealed the linkage between the increases in nutrient loading and the occurrences of high biomass blooms. Eutrophication was one of the important causes that involved in high occurrence of HAB. The main sources of nutrients potentially stimulating HABs included terrestrial runoff, aquaculture selfpollution, atmospheric deposition, sea projects and other pollution events in the ocean. Studies showed that the input from land contaminations and the selfpollution of marine aquaculture accelerated eutrophication in coastal waters and were also important impact factors on red tide. Researches suggested that nutrient composition could affect the species composition of phytoplankton as well as the development of some HABs. The changes in nutrient supply ratios, primarily N∶P, often resulted in shifts in red tide species composition. The correlation between cysts and formation of HAB was discussed from the viewpoi nt of transformation of cyst and vegetative cell, the effects of trace elements and other organic substances on the occurrence of HAB were presented also. It indicated that the nutrient control could be an effective way to reduce the risk of red tide occurrence. Seaweed would play an important role for decreasing marine eutrophication. Among the different methods of red tide controlling studied, seaweed biomass has received much attention due to the cost saving, low sensitivity to environmental and impurity factors, the possible contaminant recovery from the biomaterial and its elevated adsorption capacity. Cultivated seaweeds have very high rates of productivity higher than that of seaweed in its natural habits and grow well in water bodies with higher nitrogen and other nutrients. Seaweeds are able to absorb large quantities of nitrogen, phosphorus and carbon dioxide, produce large quanti ties of oxygen, and have excellent effect on decreasing eutrophication. Large amounts of C, N and P are accumulated into seaweed tissues as they accumulate considerable biomass over a period of months or years depending on the cultivation season. When seaweeds are harvested, nutrients are removed from the sea area. An investigation was carried out for inorganic nitrogen and inorganic phosphorus concentration at Lusi Coast, Qidong County, Jiangsu Province in China, where there were about 270 hm2 for Porphyra yezoensis cultivation with eutrophic sea water in recent years. While during Porphyra yezoensis cultivation, from Sep 2003 to May 2004, the concentration of ammonium nitrogen declined form 0.511-0.778 mg·L^-1 to 0.006-0.057 mg·L^-1, nitrite nitrogen concentration declined from 0.010-0.040 mg·L^-1 to 0.001-0.009 mg·L^-1, and nitrate nitrogen concentration declined from 0.466-0.549 mg·L^-1 to 0.286-0.0568 mg·L^-1, the average concentration of inorganic phosphorus declined from 0.024 mg·L^-1 to 0.019 mg·L^-1. Furthermore, during five hours, the concentration of ammonium nitrogen in the seawater declined form 220.88 μmol·L^-1 to 8.59 μmol·L^-1 by cultivated Gracilaria lemanaiformis, and the concentration of ammonium nitrogen declined form 213.84 μmol·L^-1 to zero by cultivated Enteromorpha clathrata. Other bioremediation mechanisms of seaweed inhibiting the red tide microalgae such as nutrients competition and allelopathic effects were also discussed.     

益生菌在水产养殖方面的研究进展

简述了生物修复技术和益生菌概念的发展,综述了在养殖生态环境中利用益生菌来净化水质和修复养殖水体等方面所取得的成果,并对微生物修复养殖水体的技术发展前景等进行了展望。     

微生物成矿技术在环境砷污染治理中的应用研究进展

近年来,微生物成矿技术成为环境污染治理领域研究热点之一.结合典型矿化菌与砷的成矿关联规律对微生物成矿作用固定砷的机制及环境污染治理中的应用进行归纳:(1)环境中的碳酸盐矿化菌、铁锰氧化菌及硫酸盐还原菌可通过诱导成矿的方式,直接促进含砷矿物的形成或生成其他矿物间接吸附砷,通过对砷的成矿产物和成矿因素分析,揭示微生物成矿机...     

Amelioration strategies for sodic soils: a review

Sodic soils are characterized by the occurrence of excess sodium (Na⁺) to levels that can adversely affect soil structure and disturb availability of some nutrients to plants. Such changes ultimately affect crop growth and yield. There are large areas of the world that exist under sodic soils and need attention for efficient, inexpensive and environmentally feasible amelioration. Sodic soil amelioration involves increase in calcium (Ca²⁺) on the cation exchange sites at the expense of Na⁺. The replaced Na⁺ together with excess soluble salts, if present, is removed from the root zone through infiltrating water as a result of excessive irrigations. Records nearly a century old reveal the use of water, crop, chemical amendment, electric current, and tillage as amelioration tools for such soils. Among the amelioration strategies, chemical amendments have an extensive usage. Owing to gradual increases in amendment cost in some parts of the world during the last two decades, this amelioration strategy has become cost‐intensive, particularly for the subsistence farmers in developing countries. In the meantime, phytoremediation with low initial investment has emerged as a potential substitute of chemical amelioration. Phytoremediation works through plant root action that helps dissolve native soil calcite (CaCO₃) of low solubility to supply adequate levels of Ca²⁺ for an effective Na⁺−Ca²⁺ exchange without the application of an amendment. Although significant progress has been achieved in improving amelioration methods, a great deal of work remains to analyse the economics of such methods with focus on (1) the long‐term sustainability of the amelioration projects and (2) the consequences of amelioration for the farmer himself, other growers and society as a whole. Computer modelling may help assess economic viability of different soil amelioration methods to extend results broadly to other similar locations. In addition, computer modelling to stimulate movement and reactions of salts in sodic soils has been a potentially useful complement to experimental data. However, such models need evaluation under field conditions. Copyright © 2001 John Wiley & Sons, Ltd.