毒死蜱降解细菌XZ-3的分离及降解特性研究

从某农药厂排污口的污泥中采样,经驯化富集后筛选到1株能高效降解毒死蜱的细菌XZ-3,经过对其形态、生理生化特征及16S rDNA的分析,鉴定该菌株为节杆菌属（Arthrobactersp.）.测定了不同碳源、pH、温度及毒死蜱浓度对细菌降解能力和生长量的影响,以培养液在波长400 nm下的光密度值表示细菌生长量,液体介质中毒死蜱的提取采用漩涡振荡提取法,提取溶剂为石油醚,毒死蜱的测定采用紫外分光光度法.结果表明,该菌株24 h内对100 mg·L^-1毒死蜱的降解率高达86.8%;在外加碳源浓度为0.3%时降解率最大;细菌的生长量随着外加碳源浓度的升高而增加;pH在偏酸和偏碱性的条件下降解率较大,pH 9.0时达到最大,细菌的生长量在pH 8.0～10.0偏碱性的条件下较大;在毒死蜱浓度为100　mg·L^-1时降解率最大,该菌具有较强的抗药性,当毒死蜱浓度达到1?000　mg·L^-1时仍能生长,细菌的生长量在800　mg·L^-1时达到最大,绝对去除量随毒死蜱浓度的提高而增加;细菌的生长和降解需要适宜的温度,30℃培养时,降解率和生长量最大.本研究提出了细菌XZ-3生长和降解毒死蜱的最佳培养条件,可为农药污染治理及生产污水处理提供理论依据.     

甲苯、邻二甲苯和二氯甲烷混合气体降解菌群构建及其性能研究

挥发性有机物（VOCs）排放导致一系列环境问题,而生物法是一项绿色处理技术.本实验选取3种VOCs（甲苯、邻二甲苯、二氯甲烷）作为模型污染物,利用甲苯、邻二甲苯降解菌Zoogloea resiniphila HJ1（菌株HJ1）及二氯甲烷降解菌Methylobacterium rhodesianum H13（菌株H13）构建复合菌株,采用“专属菌+综合菌”模式以复合菌株和驯化污泥构建复合强化菌群.研究表明,复合菌株可完全降解400 mg·L^-1甲苯、256 mg·L^-1邻二甲苯、200 mg·L^-1二氯甲烷,矿化率分别为74.3%、61.1%、82.7%.复合菌株可完全降解480 mg·L^-1混合污染物（3种污染物浓度比为1∶1∶1）,降解速率依次为甲苯>邻二甲苯>二氯甲烷.经过优化,菌株HJ1和菌株H13最佳配比被确定为1∶5.复合强化菌群不仅大幅提高了 邻二甲苯、二氯甲烷降解速率,还提高了混合污染物矿化率.甲苯、邻二甲苯的存在对二氯甲烷降解产生明显抑制效应,而低浓度二氯甲烷 （< 240 mg·L^-1）对甲苯、邻二甲苯降解无明显抑制作用.本研究为VOCs生物净化过程中菌群构建提供数据支撑.     

二甲戊乐灵降解细菌的分离及降解特性

分离鉴定了二甲戊乐灵降解细菌 ,并研究了培养条件对二甲戊乐灵降解和细菌生长的影响 .结果表明 ,所分离的29株细菌中有3株在3d内对100mg·L^-1二甲戊乐灵的降解率在80%以上 ,选择HB-1、WB-12株细菌进一步研究 ,此2株细菌经鉴定分别属于假单胞菌(Pseudomonas)和玫瑰色微球菌(Mirococcusluteus) .结果表明 2株细菌在中性培养液中外加碳源浓度为0.2%、二甲戊乐灵浓度不大于100mg·L^-1、30～40℃培养的条件下 ,细菌生长量和二甲戊乐灵的降解率都达到最大.     

土壤微生物对苯的降解研究

使用大庆油田石油污染土壤中分离出优势菌种(革兰氏阴性G^-、黄杆菌属Flavobacterium),在实验室可控条件下,研究了该菌种对苯的降解规律和特点.研究发现:微生物对苯浓度耐受范围8.8～17.6 mg·L^-1,大于17.6mg·L^-1时,对该菌株产生明显的抑制作用.降解体系在pH为6.5～7.0之间达到对苯的较高降解水平,最佳降解率出现在苯初始浓度7.04～13.2mg·L^-1之间;苯在微生物细胞内外的浓度变化趋势呈现一致.-lgP(P为有机溶剂苯在细胞膜和水相中的分配系数的比值)的变化能够较好的表征苯在微生物细胞内外的降解趋势和毒性变化;当体系中苯的初始浓度大于8.8mg·L^-1时,苯的降解率与P值变化趋于一致.     

五种水生植物对水中铀的去除作用

采用水培实验,研究了浮叶植物野生水葫芦(Eichhornia crassipes)、漂浮植物浮萍(Lemna minor L)、满江红(Azolla imbircata)、沉水植物菹草(Potamogeton crispus)、挺水植物空心莲子草(Alligator Alternanthera Herb)在初始铀浓度分别为0.15、1.50和15.00 mg·L^-1水中的生长状况及它们对水中铀的去除能力.结果表明,在21 d的水培试验期内,满江红对铀表现出了最强的抗性,0.15、1.50和15.00 mg·L^-1的铀对满江红的生长抑制率分别只有4.56%、2.48%和6.79%,而满江红对水中铀的去除率分别达到了94%、97%和92%.进一步的试验表明,每1 L水中种植7.5 g满江红,可以获得最大的铀去除率,将初始铀浓度为1.25、2.50、5.00和10.00 mg·L^-1的水体降至国家排放标准(GB 23727—2009)规定值(0.05 mg·L^-1)以下分别需要17、19、23和25 d.研究结果为进一步开展铀污染水体植物修复的研究打下了基础.     

一株降解邻苯二甲酸酯真菌的筛选及其降解特性研究

采用富集培养法,从PAEs污染的农田土壤中筛选出1株邻苯二甲酸酯类化合物(PAEs)降解真菌F9,经形态学特征及18S rDNA序列分析,初步鉴定为爪哇正青霉(Eupenicillum javanicun).通过正交试验研究,得出菌株F9的最优降解条件是:C:N为20:1、pH为7.0、最佳PAEs初始浓度为50 mg·L^-1.菌株F9对土壤中复合PAEs(DMP、DEP和DOP)有良好的降解效果.在30 d培养期内,可将灭菌土壤中300 mg·kg^-1的PAEs降解65.2%,且培养第一阶段(0~15 d)的降解率远高于第二阶段(16~30 d).     

降解微囊藻毒素菌种的筛选和活性研究

研究了滇池底泥和表层水体中的微生物菌群降解微囊藻毒素(Microcystins, MCs)的能力差异,发现底泥中的微生物菌群对MCs有更强的生物降解能力.采用从滇池水华蓝藻细胞中提取提纯的微囊藻毒素作为微生物生长的唯一碳源和氮源,先后经过液体和固体培养基培养后,通过挑取单克隆菌落,分别从底泥中筛选出了能够降解MC-RR和LR的5种不同微生物菌种.其中筛选的菌种D降解MCs的能力最强,在3 d内可将初始浓度分别为60.1 mg·L^-1和38.7 mg·L^-1的MC-RR和LR全部降解,日均降解MC-RR和LR的速率分别高达20.0 mg·L^-1和12.9 mg·L^-1.     

1株耐油甲醛降解菌的分离鉴定及降解特性

烹饪油烟的健康危害一直以来受到广泛关注.以甲醛为代表的醛类污染物是烹饪油烟排放的主要污染物之一.微生物法降解甲醛具有工艺简单、成本低及无污染等优点.本研究从烹饪油烟冷凝液中分离筛选出1株具有甲醛降解能力的菌株XF-1,经序列鉴定结合菌落形态特征及生理生化试验,该菌株被鉴定为解淀粉芽孢杆菌（Bacillus amyloliquefaciens sp.）.该菌株具有能耐受高油环境的性能,最大耐受浓度为900 g·L^-1.在甲醛浓度为100 mg·L^-1的培养基中,菌株XF-1在34 h内的甲醛降解率为95.80%;当甲醛初始浓度<300 mg·L^-1时,菌株XF-1能够在120 h以内完全降解溶液中的甲醛;甲醛浓度为800 mg·L^-1时,在96 h,菌株XF-1的降解率达到73.01%,并可耐受1.5 g·L^-1浓度的甲醛.通过单因素（pH、接种量、甲醛浓度和温度）试验,得到该菌株最佳生长温度为30℃、最佳生长pH为6左右,最佳接种量为10%.利用GC-TOF-MS进一步分析测定了菌株的胞外代谢产物,推测该菌株降解甲醛的途径可能为核酮糖单磷酸（RuMP）同化途径.结果表明,从烹饪油烟冷凝液中筛选得到的甲醛降解菌XF-1对甲醛具有良好的降解能力,并能够耐受高油环境.该菌对利用生物技术处理烹饪油烟中的甲醛具有良好的开发应用前景.     

多环芳烃降解菌的分离鉴定及其生理特性研究

从兰州石化污水处理厂的污泥中分离出一株能分别以萘、蒽为唯一碳源生长的细菌(BDP01). 通过菌株形态观察及16S rDNA序列比对, 确定该菌株属于假单胞菌属的绿脓杆菌(Pseudomonas aeruginosa). 菌株在LB培养基中48 h内呈对数生长, 48 h到72 h进入生长稳定期, 72 h后开始进入衰亡期;其最佳培养温度为30 ℃, 最适生长pH为中性或弱碱性, 该菌能在萘和蒽的质量浓度分别为100 mg·L^-1和50 mg·L^-1的无机盐培养基中良好生长, 与已报道的其他微生物比较, BDP01在较短时间内具有较强的降解多环芳烃能力, 1%的接种量15 d内可降解89.64%的萘和77.21%的蒽. 采用PCR和琼脂糖凝胶电泳技术检测到菌株基因组中有邻苯二酚2,3-双加氧酶 (C23O)基因. 测序结果与NCBI数据库发布的C23O基因序列相似度为92%. 该酶在20~65 ℃以邻苯二酚为底物时, 细胞裂解液中酶活力变化范围为13.10~540.86 U.     

17α-乙炔基雌二醇降解菌的分离鉴定及降解特性

从避孕药生产厂废水处理站的活性污泥中驯化、分离到1株能够以17α-乙炔基雌二醇(17-αethynylestradiol,EE2)为唯一碳源和能源生长的菌株JCR5.经过对其形态特征、生理生化以及16S rDNA序列分析,该菌株为鞘氨醇杆菌属(Sphingobacterium sp.).研究表明,菌株JCR5利用EE2生长的适宜温度为25～40℃,培养基初始pH为7～9.金属离子Ni²⁺、Mn²⁺、Cu²⁺、Fe³⁺能够促进菌株的生长,而Zn²⁺、Ag⁺、Pb²⁺、Ca²⁺和Al³⁺离子对菌株的生长具有不同程度的抑制作用.菌株JCR5在10d内对初始底物浓度为30mg·L^-1EE2的降解率可达到87%.     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.