3DBER-S反硝化脱氮性能及其菌群特征

针对污水处理厂尾水TN去除问题,采用16S rDNA克隆文库法,探究了3DBER-S(三维电极生物膜耦合硫自养脱氮工艺)的强化脱氮机制及其菌群特征. 结果表明,I(电流)和HRT(水力停留时间)对3DEBR-S中氢自养和硫自养反硝化作用所占比例的影响较大,但对脱氮效率影响不显著. 当进水C/N〔ρ(COD_Cr)/ρ(TN)〕为1、ρ(NO₃--N)为35 mg/L、I为300 mA、HRT为4 h时,NO₃--N和TN去除率可分别稳定在80%和74%以上. 16S rDNA克隆文库结果显示,反应器中β变形菌纲为优势菌群,占47.89%〔以OUT(操作单元)计〕. 在β变形菌纲中,与具有反硝化功能的陶厄氏菌属(Thauera)相似的细菌所占比例最大,为52.94%;与可分别利用硫和氢为电子供体进行反硝化脱氮的硫杆菌属(Thiobacillus)和食酸菌属(Acidovorax)相似的细菌分别占17.65%和14.71%. 3DBER-S中存在异养联合氢自养和硫自养反硝化协同去除硝酸盐氮的作用,可为反硝化脱氮提供充足的电子供体,节约了有机碳源消耗,并保证了稳定高效的脱氮效果.      

Bacterial diversity in activated sludge from a consecutively aerated submerged membrane bioreactor treating domestic wastewater

The bacterial diversity of activated sludge from submerged membrane bioreactor (SMBR) was investigated. A 16S rDNA clone library was generated, and 150 clones were screened using restriction fragment length polymorphism (RFLP). Of the screened clones, almost full-length 16S rDNA sequences of 64 clones were sequenced. Phylogenetic tree was constructed with a database containing clone sequences from this study and bacterial rDNA sequences from NCBI for identification purposes. The 90.6% of the clones were a?l...     

A2/O与倒置A2/O工艺低温条件下的氨氮去除能力解析

对相同进水、平行运行的A²/O与倒置A²/O工艺的冬季氨氮（NH₄⁺-N）去除能力进行了全面解析.在运行水温为14℃时,倒置A²/O工艺表现出更低的NH₄⁺-N容积去除负荷［0.13 kg·（m³·d）^-1和0.29 kg·（m³·d）^-1］和氨氧化速率（AOR）［0.07 kg·（kg·d）^-1和0.11 kg·（kg·d）^-1］,而26℃时两个工艺则相差无几.两个平行工艺中的氨氧化菌（AOB）种群定量结果几乎始终相等（倒置A²/O工艺为3.2%±0.24%,A²/O工艺为3.4%±0.31%）.克隆文库分析的结果表明,造成低温时倒置A²/O工艺中具有较低氨氮去除能力的原因是其AOB优势种属为AOR较慢的慢生型（K-生长策略）亚硝化螺菌属（Nitrosospira）,而在A²/O工艺中则为AOR较快的快生型（r-生长策略）亚硝化单胞菌属（Nitrosomonas）;而在26℃环境下两个工艺中的优势种属则均为Nitrosomonas.结合对污染物沿程去除过程的全面分析,发现尽管温度是决定AOB优势种属演替的首要原因,但由于倒置A²/O的工艺结构变化造成其好氧单元具有较高的COD负荷和高NH₄⁺-N浓度等不利于AOB生长的因素,决定了其可以在常规城市污水的条件下出现K-生长策略型的优势AOB种属.因此倒置A²/O针对异养菌（聚磷菌与反硝化菌）的工艺构造变化却通过COD负荷等间接影响到自养型氨氧化菌的种群分布与演替,并最终造成工艺在低温条件下硝化能力的减弱.     

Seasonal variation of microbial populations and biomass in Tatachia grassland soils of Taiwan

To investigate the seasonal variations of microbial ecology in grassland of Tatachia forest, soil properties, microbial populations, microbial biomass, and 16S rDNA clone library analysis were determined. The soil had temperatures 6.6–18.4°C, pH 3.6–5.1, total organic carbon 1.11–10.68%, total nitrogen 0.18–0.78%, and C/N ratios 3.46–20.55. Each gram of dry soil contained bacteria, actinomycetes, fungi, cellulolytic, phosphate-solubilizing microbes, and nitrogen-fixing microbes 4.54 × 10⁴ to 3.79 × 10⁷, 3.43 × 10² to 2.17 × 10⁵, 5.74 × 10³ to 3.76 × 10⁶, 1.97 × 10³ to 1.34 × 10⁶, 8.49 × 10² to 5.59 × 10⁵, and 3.86 × 10² to 3.75 × 10⁵ CFU, respectively. Each gram of soil contained 117–2,482 μg of microbial biomass carbon, 23–216 μg of microbial biomass nitrogen and 9–29 μg of DNA. The microbial populations, microbial biomass, and DNA decreased stepwise with the depth of soil, and they had low values in winter seasons. The microbial populations, microbial biomass carbon, microbial biomass nitrogen, and DNA at the BW2 horizon were 8.42–17.84, 19.26–64.40, 16.84–61.11, and 31.03–46.26% of those at the O horizon, respectively. When analyzing 16S rDNA library, members of Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, candidate division TM1, candidate division TM7, Gammatimonadetes, and Verrucomicrobia were identified. Members of Proteobacteria (44.4%) and Acidobacteria (33.3%) dominated the clone libraries. Within the phylum Proteobacteria, α-, β-, and γ-Proteobacteria were most numerous, followed by δ-Proteobacteria.     

Analytical solutions of three-dimensional contaminant transport in uniform flow field in porous media: A library

The purpose of this study is to present a library of analytical solutions for the three-dimensional contaminant transport in uniform flow field in porous media with the first-order decay, linear sorption, and zero-order production. The library is constructed using Green’s function method (GFM) in combination with available solutions. The library covers a wide range of solutions for various conditions. The aquifer can be vertically finite, semi-infinitive or infinitive, and laterally semi-infinitive or infinitive. The geometry of the sources can be of point, line, plane or volumetric body; and the source release can be continuous, instantaneous, or by following a given function over time. Dimensionless forms of the solutions are also proposed. A computer code FlowCAS is developed to calculate the solutions. Calculated results demonstrate the correctness of the presented solutions. The library is widely applicable to solve contaminant transport problems of one- or multiple- dimensions in uniform flow fields.     

图书馆员终身学习是时代发展的要求

为适应知识经济时代发展的要求,为图书馆实现现代化、数字化的管理,图书馆必须有一支高素质,富有活力,勇于进取的专业人员队伍。本文列举了现代化图书馆对馆员的要求,说明为达到这些要求,必须进行有计划的终身学习,并提出了实现终身学习的途径。     

黄孢原毛平革菌酵母双杂交cDNA文库的构建及应用

作为研究木质素降解系统的模式微生物黄孢原毛平革菌,迄今还没有蛋白-蛋白相互作用方面的报道.本研究利用酵母双杂交技术构建了低氮培养基中培养2d和3d的酵母双杂交cDNA文库,分别得到2.5×105和3.0×105个重组子.以14-3-3蛋白为钓饵筛选3d cDNA文库,在SD/-Ade/-His/-Leu/-Trp缺陷培养基平板上共获得了约600个单克隆,进一步分析发现,有30个克隆可激活3个报告基因.分离自这些克隆中的质粒DNA能转化大肠杆菌.利用HaeⅢ和Sau3AⅠ限制酶切分析可将它们分为4类.序列测定和同源分析结果表明,其中一类为14-3-3蛋白基因,提示14-3-3蛋白可形成二聚体,另外3类在GenBank没有明显同源的基因.通过SBASE网站预测,编号为Y2H333的克隆含有一个OB-fold核酸结合结构域(OB-fold nucleic acid binding domain).这些研究结果表明,所构建的黄孢原毛平革菌cDNA酵母杂交文库是成功的,14-3-3蛋白在黄孢原毛平革菌中能以蛋白-蛋白相互作用的形式发挥功能.图4表1参28     

矿化垃圾生物反应器中的细菌多样性分析

为探究准好氧生物矿化垃圾床处理渗滤液过程中的微生物作用机理,研究建立了16S r DNA克隆文库及PCRRFLP技术以研究矿化垃圾反应器的细菌多样性。结果表明:矿化垃圾反应器细菌具有高度多样性,反应器内有36种细菌分别属于13个纲,变形菌纲占绝对优势占70%(其中β-变形占56.5%,γ-变形菌纲占10%),拟杆菌纲、鞘氨醇菌纲,芽孢杆菌纲也具有一定优势;3%的Nitrosomonas属是渗滤液氨氮转化成亚硝酸盐氮的主要功能微生物,由于亚硝酸盐氧化菌不存在或丰度极低,因此造成反应器内亚硝酸盐积累;Thauera属(17%)和Thiobacillus denitrificans属(10%)是反应器内主要优势微生物属,是反应器内反硝化脱氮的功能微生物,由于Thauera属在好氧条件下具有反硝化特性,Thiobacillus denitrificans为严格自养反硝化菌,因此反应器脱氮主要途径为好氧反硝化、自养反硝化。     

环境科学数字图书馆信息资源建设中的著作权问题

针对数字图书馆信息资源建设中面临的著作权问题,依照著作权法等相关法律,分析了环境科学数字图书馆建设中涉及到的实体馆藏文献数字化、虚拟馆藏等著作权问题,并提出了完善相关法律、加强著作权集体管理体制、建立图书馆版权联盟等对策与措施。