聚乙烯醇降解菌的筛选鉴定及其降解特性的研究

从绍兴水处理发展有限公司的曝气池污泥中筛选到6株聚乙烯醇（ PVA）降解功能菌株,编号为rF1、rF2、rF3、rF4、rF5和rF6。通过16S rDNA测序比对表明其分别为Pseudochrobactrum sp、解淀粉芽孢杆菌（Bacil－lus amyloliquefaciens）、芽孢杆菌（Bacillus sp）、门多萨假单胞菌（Pseudomonas mendocina）、杆菌属（Lysinibacillus sp）、不动杆菌（ Acinetobacter sp ）。在自配培养基中,有3株菌PVA降解率可达70％～80％,在印染废水中,有5株菌PVA降解率可达到90％以上。其中rF1、rF2和rF5无论是在自配培养基还是印染废水中都具有较好效果,表明具有一定的实际应用价值。     

辽东湾北岸滨海湿地降解苯甲酸类化合物的微生物研究

用富集培养法从辽东湾北岸滨海湿地土壤中分离到以苯甲酸为唯一碳源和能源的细菌9株。经鉴定BJI、BJ2属于不动杆菌属(Acinetobacter sp),BJ3,BJ9,BJ8属于假单胞菌属(Pseudomonas sp),BJ4,BJ5,BJ6,BJ7属于无色杆菌属(Achromobacter sp)。考察了菌株的底物特异性。通过比较单菌株和混合菌的降解效果,得出了优势混合菌。其最适降解条件为：pH8．0,温度25℃,时间48h。     

原油降解菌的筛选鉴定及降解特性的研究

实验从河北省唐山市柳赞镇冀东油田油井污水中筛选出8株以原油为唯一碳源的降解菌株(编号为T1-8),通过形态学特征观察以及16SrDNA分子生物学鉴定,确定这8个菌株分别为铜绿假单胞菌(Pseudomonas aeruginosa)、金黄色葡萄球菌(Staphylococcusaureus)、Bacillus safensis、短小芽孢杆菌(Bacillus pumilus)、嗜冷杆菌(Psychrobacter pulmonis)、鲁氏不动杆菌(Acinetobacter lwoffii)、纺锤芽孢杆菌(Bacillus fusiformis)和洋葱伯克霍尔德氏菌(Burkholderia cepacia)。采用无机盐培养基,以华北任丘油田原油为唯一碳源,分别对上述8种菌株进行原油降解能力测试,通过为期7d的降解,其相对应的降解率分别为67.14%、43.13%、30.37%、24.74%、43.00%、37.94%、55.28%和14.51%,而且其中的金黄色葡萄球菌和嗜冷杆菌对原油具有降解能力为首次报导。后续对铜绿假单胞菌进行了影响降解率的单因素实验,实验结果显示在pH为7、初始原油浓度为5g/L和菌液接种量1mL(约1.8×1010cfu/mL)时铜绿假单胞菌对原油的降解率达到其最大值67.14%。     

对苯二甲酸的微生物降解

从处理对苯二甲酸(PTA)生产废水的上流式厌氧生物滤床(UASB)底部活性污泥中分离到一株降解活性较高的细菌T_6.当PTA为唯一碳源时,降解率可达98％,菌体接种量的大小对降解速度有一定影响.该菌可以分别在好氧和厌氧条件下降解PTA.试验表明,降解PTA的酶为胞内酶,经鉴定,T_6菌为假单胞菌(Pseudomonas sp.).其某些特性与已知种有差异,尚待进一步确定.     

醋酸钙不动杆菌PHEA-2对苯酚的降解特性研究

自炼油厂污水中分离的醋酸钙不动杆菌(Acinetobacter calcoaceticus) PHEA-2具有 较强的苯酚降解能力.在温度为30℃和接种量为1%条件下,该菌在24h内完全降解苯酚的浓度 为300mg/L;该菌的最适生长和最适降解苯酚温度为30℃;在pH值5～10范围内能保持对苯酚的 降解能力.醋酸钙不动杆菌PHEA-2的苯酚降解反应符合Monod动力学模式,其反应的米氏常数K m为275mg/L,最大反应速度Vm为41mg苯酚/(10⁸·h).一定量的葡萄糖(5%)促进PHEA-2菌体的 生长,从而提高了整个培养体系降解苯酚的能力.     

环境激素对叔辛基酚降解菌的筛选、鉴定及降解特性

为了研究环境激素4-t-OP(对叔辛基酚)的生物降解,从扬州市汤汪生活污水处理厂二沉池污泥中筛选得到1株能以4-t-OP为唯一碳源进行生长的降解菌株,标示为TW30,16S rRNA测试其为不动杆菌属(Acinetobacter sp.),通过摇瓶试验测试其降解活性.结果表明:在40℃、初始pH为6.0、ρ(4-t-OP)为5 mg/L的无机盐培养基中,5 d后降解率可达99.03%;降解过程满足一级反应模型,降解速率常数(k)为0.875 d-1,半衰期(t1/2)为0.8 d.这说明TW30是一株高效的4-t-OP降解菌.此外,培养温度的升高和额外Ca2+、Mn2+的加入可以提高TW30降解4-t-OP的效率,而在5～25 mg/L范围内提高初始ρ(4-t-OP)以及额外加入磷酸盐、NH4+、Mg2+、Fe2+、Na+、Zn2+、Cu2+等无机盐和葡萄糖、CH3COO-等碳源则会降低降解率.      

酚降解菌株的分离、鉴定和在含酚废水生物处理中的应用

从石油化工厂的活性污泥和废水混合物中分离到10个降解酚的细菌菌株,经16S rRNA基因序列分析,5个菌株(PD1、PD2、PD6、PD7和PD39)被鉴定为假单胞菌(Pseudomonas sp.),4个菌株(PD4、PD5、PD8和PD9)为不动杆菌(Acinetobacter sp.),1个菌株(PD3)为丛毛单胞菌(Comamonas sp.).对假单胞菌(Pseudomonas sp.)PD39菌株的酚降解特性、最适生长条件、降解底物的范围、儿茶酚1,2-双加氧酶(C12O)和儿茶酚2,3-双加氧酶(C23O)活性、含酚废水的生物处理等,进行了详细研究.结果表明,PD39菌株的最适生长和降解条件是,培养基的起始pH为7.0,培养温度为30℃,酚浓度为800 mg/L,对酚的最大降解浓度为1 200 mg/L.酚浓度为637 mg/L的工业废水经72 h处理酚的去除率达到99.96%.PD39菌株有很好的应用潜力来作含酚废水活性污泥处理系统的强化菌株.     

1株高效BBP降解菌的分离与特性研究

从湖北省荆沙河泥样中富集培养分离得到了1株能够以邻苯二甲酸丁基苄基酯为唯一碳源和能源生长的细菌并命名为HS-B1.采用形态学、生理生化和16S rDNA序列分析对其进行了鉴定,发现HS-B1是1株杆状、需氧、革兰氏阴性细菌,接触酶呈阳性反应,氧化酶呈阴性反应,不产硫化氢气体,且该菌的16S rDNA序列与琼氏不动杆菌(Acinetobacter junii)的相似性高达99%.因此初步鉴定该菌株为不动杆菌(Acinetobacter sp.).摇瓶实验表明,菌株HS-B1生长和BBP降解的最适培养条件为35℃,pH 8.0.采用0.10 mmol.L-1非离子型表面活性剂吐温-80提高了BBP在水溶液中的表观溶解度,发现在最适培养条件下,HS-B1能够在48 h内将浓度为1 000 mg.L-1BBP完全降解,证明是一株高效降解菌.底物广谱性实验中,菌株HS-B1也能够有效利用DMP、DEP、DBP等邻苯二甲酸酯类化合物,说明该菌株在处理邻苯二甲酸酯类化合物的污染治理中有独特的应用潜力.     

3株细菌对土壤中芘和苯并芘的降解及其动力学

研究了3株多环芳烃(PAHs)高效降解菌对土壤中芘和苯并芘(BaP)的降解动态,用Michaelis-Menton和Monod动力学模型对结果进行拟合.结果表明,3株细菌对芘和BaP的降解率有显著性差异.芽孢杆菌(Bacillus sp.SB02)42 d对芘和BaP的降解率均最高.当土壤中芘和BaP的初始浓度为50　mg/kg时,芽孢杆菌(Bacillus sp. SB02)、动胶杆菌(Zoogloea sp. SB09)、黄杆菌(Flavobacterium sp. SB10)42 d对芘的降解率分别为42.69%、32.88%、25.07%, 对BaP的降解率分别为33.04%、25.39％、22.02%.3株细菌对芘和BaP的降解速率也存在显著性差异.芽孢杆菌(Bacillus sp., SB02)最快,1周可降解20.88％芘和12.6%的BaP,动胶杆菌(Zoogloea sp.SB09)次之,黄杆菌(Flavobacterium sp.SB10)降解速率最慢.     

低温条件下硝基苯降解菌的筛选及鉴定

在低温(15℃)条件下,从东北制药总厂曝气池和氯霉素生产废水集水池污泥中驯化、分离得到1株以硝基苯为唯一碳源的高效降解菌株cc-2,并通过菌体形态、生理生化反应特性及16S rDNA测序对其进行分析.同时,对菌株cc-2的生长和降解硝基苯的特性进行了研究.结果表明,菌株cc-2为鲍曼不动杆菌(Acinetobacter baumannii),该菌株利用硝基苯生长的最佳条件分别是:接种量为10%,生长温度为15℃,pH值为7.菌株cc-2可在硝基苯质量浓度低于400 mg.L-1的无机盐培养基中生长代谢,当硝基苯初始浓度为200 mg.L-1时,菌株48h的降解率可达66.84%.     

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.     

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.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

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.     

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.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.     

Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.