发酵培养法筛选堆肥中产表面活性物质的菌种

微生物在城市生活垃圾堆肥中起着重要的作用 ,而某些微生物在一定条件下产生的生物表面活性剂有望改善堆肥的微环境 ,提高堆肥的效率。从不同温度的堆肥过程中 (45℃和 55℃ )筛选产生物表面活性剂的细菌 ,生物表面活性剂的产生通过测定其发酵液的张力值来判断。实验结果表明 ,堆肥过程中的确存在产生物表面活性剂的细菌 ,枯草芽孢杆菌是其主要菌之一。实验通过一系列培养条件的优化 ,使所筛选到的细菌产生活性较强、浓度较高的生物表面活性剂     

堆肥中生物表面活性剂脂肽产生菌的筛选

从农业堆肥样品中提取出4株可将发酵液的表面张力降到40mN/m以下的菌株,对该四株菌的发酵液进行薄层层析(TLC)分析,结果表明其中3株产生的生物表面活性剂可能为脂肽。选取其中一株B2对其所产的生物表面活性物质进行提纯,经过红外光谱(FT-IR)分析,证明该产物为一环脂肽类似物。该脂肽纯品可将纯水的表面张力由72.3mN/m降到29.9mN/m,CMC值为0.139g/L。实验结果表明,堆肥过程中存在能够产生生物表面活性剂脂肽的菌种,且具有良好的表面活性。     

生物表面活性剂产生菌的筛选及其对土壤重金属铅的活化作用

结合油平板和血平板方法从重金属8处复合污染的土壤样品中筛选出15株能产生物表面活性剂的细菌菌株,其中J119菌株不仅具有良好的产生物表面活性剂的性能,而且能在含铅、镉浓度分别为100～200 mg·L-1、25～100 mg·L-1的平板中生长.同时对J119菌株所产的生物表面活性剂与3种不同类型化学合成表面活性剂活化土壤中铅的效能进行了比较.结果表明,在400 mg·kg-1铅污染土壤中,J119菌株发酵液与化学合成表面活性剂活化土壤中铅的效果相当;与对照相比,在800 mg·kg-1铅污染土壤中,J119菌株发酵液处理使土壤中有效性铅的浓度增加51.1%,而3种化学合成表面活性剂CTAB、SDS、Tween-80处理土壤中有效态铅浓度仅比对照增加28.7%、26.2%和16.0%.另外,J119菌株产生的生物表面活性剂与供试3种化学合成表面活性剂对土壤中铅的活化作用之间存在显著差异.     

生物表面活性剂产生菌的筛选及培养条件优化

采用富集培养、蓝色凝胶平板筛选和发酵液排油活性测定的方法,从沈阳蜡化厂活性污泥中分离筛选到一株产表面活性剂菌株,并通过摇瓶发酵实验对该菌株产表面活性剂的培养条件进行了优化.结果表明:该菌株产表面活性剂的最佳碳源为废油,氮源为尿素,初始pH值为7.0,接种量为5％,培养温度为35℃,培养72 h后发酵液排油圈直径可达6....     

生物表面活性剂产生菌的筛选及产剂性能研究

从长期被汽油污染的土壤中,筛选出了一株表面活性剂产生菌BSZ-07,初步确定其为铜绿假单胞菌。通过正交试验,优化出了BSZ-07的最优产剂条件。BSZ-07在48h内可使发酵液的表面张力降至34.2mN/m,且乳化性能稳定,是一种较优良的生物表面活性剂产生菌。经FTIR分析及元素分析,初步确定其所产表面活性剂为鼠李糖脂。     

脂肽类生物表面活性剂产生菌的分离及特性研究

从石油污染土壤中分离筛选获得一株产生生物表面活性剂菌株Y8A,经生理生化实验、16S rDNA序列分析等将其鉴定为芽孢杆菌属（Bacillus sp.）.Y8A能在22h内将发酵液的表面张力从68.3mN·m-1降到23.5 mN·m-1.经TLC和傅立叶红外光谱分析, 菌株Y8A产生的生物表面活性剂为脂肽类.20mg·L-1 Ca2+和Fe2+能显著促进其生长和表面活性剂的产生;菌株Y8A在20～30℃,pH 5～12范围内产生表面活性剂的能力较强;LB培养基中添加1%乳糖对生长的影响不大,但能够明显促进Y8A产生生物表面活性剂,而葡萄糖、蔗糖抑制表面活性剂的产生.Y8A能够促进石油降解菌Y1D和F11对石油的降解和功夫菊酯降解菌ZZH对功夫菊酯的生物降解.     

产表面活性剂解烃菌的筛选及其降解条件研究

以原油为唯一碳源和能源,从新疆克拉玛依油田土壤中筛选出1株能产生物表面活性剂的高效解烃菌XJBM,经形态观察、生理生化特征和Biolog分析,初步鉴定该菌为铜绿假单胞菌(Pseudomonas Aeruginosa)。薄层色谱分析结果表明,XJBM产糖脂类生物表面活性剂,在最适发酵条件下,生物表面活性剂的产量可达2.25 g/L,可将发酵液表面张力从68.20 m N/m降低到32.50 m N/m,乳化指数(E24)达到81.8%。采用单因素试验对影响XJBM降解率的因素进行了研究,得出最适降解条件为p H 7.5,温度30℃,盐浓度5 g/L,接种量10%。在此条件下,菌株对1%石油烃的7d降解率为63.78%。     

红球菌SY095产生物表面活性剂对沉积物中铅和铜的去除

采用批次淋洗的方法研究了红球菌SY095产生物表面活性剂对沉积物中Pb和Cu的去除作用,考察了生物表面活性剂浓度、pH、温度、振荡时间、提取次数等条件对重金属去除效果的影响,并分析处理前后重金属的形态变化。结果表明:随着生物表面活性剂浓度的增加,2种重金属的去除率增大;Pb在淋洗剂pH为6时解吸效果最好,达到34.16%,而Cu的去除效果随着pH的升高而增加;生物表面活性剂对沉积物Pb和Cu去除率分别在25,40℃时达到最大;随着振荡时间和提取次数的增加,Pb和Cu去除率升高,3次洗脱后累积去除率分别为39.12%和51.26%;对沉积物重金属的形态分析发现,生物表面活性剂可有效去除酸提取态Pb和Cu。     

产表面活性剂的石油降解菌降解特性研究

从石油化工厂附近的污染土壤中分离到一株产表面活性剂的石油降解菌,经鉴定为假单胞菌属,其生物表面活性剂的产量为0.53g/L。文章研究了该菌株在不同条件下的生长状况,并与两株不产表面活性剂的菌对比测定了其石油降解的效率,生物表面活性剂在此过程中起了重要作用。将表面活性剂产生菌与其它菌株组合能有效的提高菌株对石油的降解效率,最终使另外两种菌株的降解率分别提高了7.38%和18.33%。     

生物表面活性剂清洗土壤有机污染物的研究与展望

重点阐述了生物表面活性剂清洗土壤有机污染物的机理及影响因素.根据国内外最新文献,对使用生物表面活性剂溶液修复有机物污染土壤的研究进展进行了综述.并展望了生物表面活性剂在清洗土壤有机污染物中的研究前景.     

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.     

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

ＲｅｍｏｖａｌｏｆｈｅａｖｙｍｅｔａｌｓｆｒｏｍｓｅｗａｇｅｓｌｕｄｇｅｂｙｌｏｗｃｏｓｔｉｎｇｃｈｅｍｉｃａｌｍｅｔｈｏｄａｎｄｒｅｃｙｃｌｉｎｇｉｎａｇｒｉｃｕｌｔｕｒｅＷｕＱｉｔａｎｇ，ＮｙｉｒａｎｄｅｇｅＰａｓｃａｓｉｅ，ＭｏＣｅｈｕｉＦ...     

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.     

Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field ＞ tree land ＞ fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT ＞1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.     

Sorption of 1-naphthol by plant cuticular fractions

The contribution of aliphatic-rich plant biopolymer to sorption of hydrophobic organic compounds is significantly important because of their preservation and accumulation in the soil environment,but sorption mechanism is still not fully understood.In this study, sorption of 1-naphthol by plant cuticular fractions was examined to better understand the contributions of respective fraction.Toward this end,cuticular materials were isolated from the fruits of tomato by chemical method.The tomato cuticle sheet consisted of waxes (6.5 wt%),cuticular monomer (69.5 wt%),and polysaccharide (24.0 wt%).Isotherms of l-naphthol to the cuticular fractions were nonlinear (N value (0.82-0.90)) at the whole tested concentration ranges.The KodKow ratios for bulk cuticle (TC1),dewaxed cuticle (TC2),cutin (TC4),and desugared cuticle (TC5) were larger than unity,suggested that tomato bulk cuticle and cutin are much powerful solption medium.Sorption capability of cutin (TC4) was 2.4 times higher than the nonsaponifiable fraction (TC3).The 1-naphthol interactions with tomato cuticular materials were governed by both hydrophobic-type interactions and polar (H-bonding) interactions. Removal of the wax and polysaccharide materials from the bulk tomato cuticle caused a significant increase in the sorption ability of the cuticular material.There was a linear negative trend between K_(oc) values and the amount of polysaccharides or fraction's polarities ((N O)/C);while a linear positive relationship between K_(oc) values and the content of cutin monomer (linear R~2=0.993) was observed for present in the cuticular fractions.Predominant sorbent of the hydrophobic organic compounds (HOCs) in the plant cuticular fraction was the cutin monomer,contributing to 91.7% of the total sorption of tomato bulk cuticle.