一株染料脱色酵母菌的鉴定及脱色特性

从土壤中分离到一株活性艳红K-2BP脱色酵母菌株Y-63,根据其生理生化特征和26S rRNA基因序列相似性分析,鉴定为Pseudozyma rugulosa.该菌在16 h内对100 mg/L的活性艳红K-2BP脱色率为94%,其机理属于降解脱色.该染料脱色的最佳接种量(φ)应不低于5%,最适pH在4～9之间,(NH4)2SO4浓度(w)不低于0.1%,葡萄糖浓度(w)不低于0.2%.此外,该菌株对其它9种50 mg/L的染料(活性艳蓝X-BR、媒介漂蓝B、活性翠蓝KN-G、酸性媒介黄GG、媒介红S-80、依加仑蓝FBL 200%、弱酸艳红B、活性黑KN-B和活性红M-3BE)的脱色率在10%～96%之间.该研究表明酵母Y-63在染料废水的处理上具有较好的应用潜能.     

Cu2+、Cd2+和Cr6+对斑马鱼联合毒性作用和生物预警的研究

为了研究重金属对水生生物的联合毒性作用,以斑马鱼为受试生物,采用半静态法,在研究Cu2、Cd2和Cr6+对斑马鱼单一毒性的基础上,以获得的Cu2+、Cd2+和Cr6+的96 h-LC50数据,利用等效应曲线法研究了Cu-Cd、Cu-Cr和Cd-Cr的联合毒性作用,并综合分析环境毒理学指标的测定结果,考察利用斑马鱼作为水...     

Assessing the impact of fungicide enostroburin application on bacterial community in wheat phyllosphere

Fungicides have been used extensively for controlling fungal pathogens of plants. However, little is known regarding the effects that fungicides upon the indigenous bacterial communities within the plant phyllosphere. The aims of this study were to assess the impact of fungicide enostroburin upon bacterial communities in wheat phyllosphere. Culture-independent methodologies of 16S rDNA clone library and 16S rDNA directed polymerase chain reaction with denaturing gradient gel electrophoresis (PCR-DGGE) were used for monitoring the change of bacterial community. The 16S rDNA clone library and PCR-DGGE analysis both confirmed the microbial community of wheat plant phyllosphere were predominantly of the γ-Proteobacteria phyla. Results from PCR-DGGE analysis indicated a significant change in bacterial community structure within the phyllosphere following fungicide enostroburin application. Bands sequenced within control cultures were predominantly of Pseudomonas genus, but those bands sequenced in the treated samples were predominantly strains of Pantoea genus and Pseudomonas genus. Of interest was the appearance of two DGGE bands following fungicide treatment, one of which had sequence similarities (98%) to Pantoea sp. which might be a competitor of plant pathogens. This study revealed the wheat phyllosphere bacterial community composition and a shift in the bacterial community following fungicide enostroburin application.     

基于吸附处理废水中Pb2+的麦糟改性研究

麦糟是啤酒工业的副产物,富含有机物,具有去除废水中重金属离子的能力.为了更有效地去除废水中的Pb2 ,本实验对麦糟进行了改性研究,实验过程中选择HCl、H2SO4、H3PO4、NaCl、NaOH作为改性剂.结果表明,用1mol·L-1NaCl溶液改性13h的麦糟对Pb2 有最好的吸附能力.通过扫描电镜、X射线能谱、红外光谱分析,研究了麦糟改性机理,发现经NaCl溶液改性后的麦糟新增N-Cl基团和C-Cl基团,容易和Pb2 配位结合,从而提高了吸附能力.改性麦糟吸附Pb2 的过程中,N-Cl、C-Cl、C-O(H)以及O-H起了重要作用.     

三苯基锡对紫萍生长及酶活性的毒性作用

以紫萍作为实验生物,通过研究不同浓度的三苯基锡对紫萍（Spirodela polyrrhiza L．）根叶生长、多酚氧化酶（PPO）活性、过氧化氢酶（CAT）活性和过氧化物酶（POD）的影响,为及时发现和排除三苯基锡的污染提供理论和直观依据。结论表明：培养4d后,三苯基锡处理对紫萍叶片生长量的IC50为0．71mg／L。相同培养液条件下,PPO、CAT和POD均随着三苯基锡处理浓度的升高呈现先升高后下降的趋势。从中可以说明三苯基锡对紫萍有明显的毒性作用。     

Catalytic oxidation of gas-phase elemental mercury by nano-Fe2O3

Heterogeneous oxidation of gas-phase Hg0 by nano-Fe2O3 was investigated on a fixed bed reactor, and the e ects of oxygen concentration, bed temperature, water vapour concentration and particle size have been discussed. The results showed that Hg0 could be oxidized by active oxygen atom on the surface of nano-Fe2O3 as well as lattice oxygen in nano-Fe2O3. Among the factors that a ect Hg0 oxidation by nano-Fe2O3, bed temperature plays an important role. More than 40% of total mercury was oxidized at 300°C, however, the test temperature at 400°C could cause sintering of nano-catalyst, which led to a lower e ciency of Hg0 oxidation. The increase of oxygen concentration could promote mercury oxidation and led to higher Hg0 oxidation e ciency. No obvious mercury oxidation was detected in the pure N2 atmosphere, which indicates that oxygen is required in the gas stream for mercury oxidation. The presence of water vapour showed di erent e ects on mercury oxidation depending on its concentration. The lower content of water vapour could promote mercury oxidation, while the higher content of water vapour inhibits mercury oxidation.     

瓦斯爆炸在角联通风管网中的传播特性研究*

为研究真实通风工况下瓦斯爆炸冲击波在复杂管网内的超压演化规律及高温传播规律,采用数值模拟方法,研究角联通风管网模型中各个监测点在不同通风条件下对瓦斯爆炸冲击波超压及高温的影响规律,研究结果表明:瓦斯爆炸冲击波在角联管网传播过程中产生3个局部高压区域,高温气体主要在左、右通路内传播,斜角联分支内只受到微弱影响;管网入口风流的存在,使得爆炸初期冲击波超压经相同距离传播用时更短,峰值更大,破坏力更强;风流的存在使得管网内高温气体传播状态发生改变,斜角联分支与左通路尾部热量发生积聚,温度峰值更大。     

Effect of pH on the sonochemical degradation of organic pollutants

An increasing number of organic compounds are manufactured, consumed, and discarded every year. Incomplete destruction of these compounds in wastewater treatment plants leads to pollution of natural waters, posing great health and ecological concerns. Ultrasound, as an emerging advanced oxidation technology, can quickly and effectively degrade organic pollutants in waters. To improve removal efficiency of organic pollutants in an ultrasonic system, operational parameters, especially pH, have been frequently evaluated and optimized. This review show that pH-induced changes in volatility, hydrophobicity and Coulombic force between the target compound and cavitation bubbles leads to higher degradation at acidic pH for most compounds. In addition, pH also changes free radical formation and reactivity in water during sonication, thereby altering degradation kinetics of target compounds. However, the influence of pH is not always consistent for various organic pollutants covering a broad range of physicochemical properties and reactivities. A systematic investigation on the pH effect is necessary to elucidate how pH alters cavitation bubble dynamics and collapse, radical yield and reactivity, distribution of target compounds in the vicinity of cavitation bubbles, water matrices transformation, and ultimately the degradation kinetics of organic pollutants. This first systematic review provides valuable insight into the pH effects on organic pollutant sonolysis, helps to improve our mechanistic understanding of the sonochemical system, and sheds light on future application of ultrasound in water engineering.     

Degradation kinetics of terephthalic acid wastewater with the hybrid strains constructed with Phanerochaete chrysosporium

The degradation kinetic parameters in terephthalic acid (TPA) wastewater for the hybrid strains of Fhh and Fhhh obtained through the protoplast fusion of the fungi Phanerochaete chrysosporium (PC) and Saccharomyces cerevisiae Y99, and the native bacteria YZ1 were measured in this research. The highest level of the specific degradation rate for Fhhh and Fhh during 20h reaction were 0.2238 and 0.2163 h^‐1, which were higher than that of their three parental strains and that of the anaerobic bacteria reported. It suggested that the abilities of growth and degradation for Fhh and Fhhh in TPA wastewater were better than their three parental strains. They could create potentials for the purification of TPA wastewater with higher efficiency.     

Effects of cotton straw amendment on soil fertility and microbial communities

Maintaining soil fertility, while controlling pollution from excessive chemical fertilizer application is important for keeping soil productivity of sustainable agriculture. Variety of straws have been used and proven to be good soil amendments for increasing soil organic matter (OM) and a range of additional soil nutrients. However, little is known about the utilization of cotton straw for soil amendment. To better understand the mechanism behind cotton straw soil amendments, investigations were performed upon cucumber seedlings, where changes to soil nutrients and microbial communities were investigated. The results revealed that the cotton straw application promoted the cucumber seedling growth by significantly increasing the soil OM, available nitrogen, available phosphorus, and available potassium. The concentration of cotton straw was positively correlated to both the number of the culturable microorganisms and also the total microbial biomass within soil. Furthermore, assessment of cotton straw application using Biolog metabolic profiling and phospholipid fatty acid analysis revealed that such application increased the microbial community metabolic activity, and markedly changed the structure of microbial community. 16S rRNA gene clone library construction and phylogenetic analysis of soil bacteria revealed γ- Proteobacteria sequences dominated the cotton straw amendment soil, comprising 27.8% of the total number of analyzed sequences, while they were less represented in control soil (13.4%). On the contrary, the Sphingobacteria (7.8%) and Verrucomicrobia (2.4%) in the cotton straw amendment soil decreased after application when compared to the control soil 15.2% and 15.2%.