高效原油降解菌筛选驯化实验研究

由含油废水原有微生物种群中分离出纯种菌株，通过纯种菌株的单一菌种降解性能实验，混合菌株垢正交性能实验，筛选出7种高效原油降解菌（包括芽孢杆菌属，黄杆菌属，黄单胞菌属，和假单胞菌属），其中芽孢杆菌属降解原油能力最强，对于18．4mg/L的含油废水，降解去除率高达94％－95％，实验还表明，单种菌株降解原油的能力比混合菌株要好。     

磁场对固定化紫色非硫光合细菌脱氢酶影响的研究

研究磁场作用对固定化紫色非硫光合细菌（ＰＳＢ）脱氢酶活力的影响，选出可产生最佳磁生物效应的磁场值，并证明磁场作用一定累积效应，实验结果表明在最佳磁场作用下，最适温度为３０－４０℃，最适ｐＨ值为８，脱氢酶活力可提高３０％左右，有良好热稳定性和ｐＨ稳定性。在４℃冰箱保存４５至２１０ｄ，磁场对脱氢酶活力影响基本稳定，可保持提高２０％。磁场对菌液中加某些金属离子（Ｆｅ＾２＋、Ｍｎ＾２＋、Ｚｎ＾２＋）ｂｎ     

硫酸盐,亚硫酸盐,硫代硫酸盐对甲烷菌协同抑制作用的研究

本研究用二次回归正交设计法进行试验设计,研究了硫酸盐、亚硫酸盐、和硫代硫酸盐对甲烷菌的协同抑制作用。对试验结果分析得出了协同抑制作用动力学方程式,并发现硫酸盐、亚硫酸盐、和硫代硫酸盐对甲烷菌协同抑制作用具有可加性。     

耐铜细菌的筛选及其吸附条件优化

从电镀厂废水污泥中分离到一株高耐铜的菌株 ,它能耐受Cu2 + 的最高浓度为 560mg/L ,通过形态学观察及生理生化特性测定 ,初步鉴定为铜绿假单胞菌 (Pseudomonasaeruginosa) ,并通过正交试验确定该菌吸附Cu2 + 的最佳条件为pH 5 .0 ,接触反应时间为 0 .5h ,摇床转速为 50r/min ,菌量为 1 0 0mg。在最佳条件下 ,该菌对Cu2 + 的吸附量可达 1 4 .68mg/g。     

从武汉印染厂废水淤泥中分离出的趋磁细菌的生长与磁小体形成过程

对从武汉印染厂污泥中分离出的趋磁细菌YN-1,分别进行了5 d,10 d,20 d,25 d和30 d的纯培养与透射电镜的观察,并对30 d释放出的磁小体进行了能谱分析.结果表明:培养5 d的趋磁细菌,其体内的细胞质相对均匀,可见到铁质在细胞内输送的痕迹.随后细胞质变为不均匀,菌体内泡状物和磁小体增多;20 d后菌体膜出现自溶,可见磁小体从破裂的菌膜排出体外的现象,25 d后可见到具有鞭毛、细胞质分布均匀的“营养体”.培养30 d,菌膜基本自溶,除见有营养体外,残存大量的细胞膜碎片和磁小体,对它们的能谱分析显示,磁小体的主要无机成分为Fe.由此判断,25 d可能为该菌在培养条件下的趋磁细菌生长与磁小体形成周期.图3表1参15     

中度嗜盐菌Halomonas sp.BYS-1耐盐相关DNA片段的克隆

通过固体亚硝基胍诱变获得了Halom onassp.BYS-1的盐敏感突变株BYS-1M.以pBBR1MCS-2为载体在E.coliDH5α中构建了BYS-1的基因文库.以文库菌E.coliDH5α(pBBR-X)为供体菌、E.coliWD803(pRK2013)为辅助菌、BYS-1M为受体菌进行三亲接合,筛选到了恢复耐盐性能的接合子HR-23,提取接合子HR-23的重组质粒pHR23,酶切确定其插入的耐盐相关DNA片段大小分为5.4 kb.该片段为Halom onassp.BYS-1耐盐相关基因的克隆奠定了基础.图5表1参14     

产冷适应复合酶菌株Pseudomonas sp.NJ197的选育、发酵条件及酶学性质

从南极普利兹湾深海沉积物中筛选到一株同时产多种冷适应酶的菌株NJ197,细菌学形态鉴定及16S rDNA序列分析表明,该菌株属于假单胞菌属(Pseudomonas).生长特性研究表明,该菌株属于耐冷菌,其最适生长温度为5~15℃.NJ197菌株能利用多种单一的碳、氮源产酶,最适产酶温度为20℃,最高产酶温度为30℃.粗酶液经硫酸铵盐析、DEAE cellulose-52柱层析初步分离纯化后进行酶学性质的研究.该菌株所分泌复合酶中脂肪酶和淀粉酶的活力最高,它们的最适作用温度分别为30℃和35℃,最适pH值分别为9.0和9.5,对热敏感,是典型的碱性冷适应复合酶.Ca2 、Mn2 、Cu2 、Co2 、Fe3 对该复合酶有较为明显的激活作用,而Zn2 、Hg2 、Rb2 、Cd2 、EDTA则能抑制酶活.其中脂肪酶能在高浓度的SDS、CHAPS等变性剂中表现出较好的稳定性.图5表2参21     

Groundwater quality: Responsible agriculture and public perceptions

The chief sources of groundwater contamination on farms come from point sources and diffuse sources. Possible point sources are feedlots, poorly-sited manure piles, septic sewage-treatment systems—all of which can release nitrate, phosphates and bacteria— and sites of chemical spills. Diffuse sources are typified by excess fertilizer leaching from a number of arable fields. The basis of quality standards for drinking-water is discussed in relation to common contaminants present on farms. Samples of drinking-water were collected in 1991–1992 from wells on about 1,200 farms in order to study the quality of rural groundwater in Ontario. Analysis showed that approximately one third of wells were contaminated with bacteria, 14% were contaminated with nitrate, two wells were contaminated with pesticide, but 40% were considered unsafe because of the presence of at least one contaminant. These values were similar to those reported for similar regions in the U.S. There was no significant effect of agricultural practice on the proportion of contaminated samples. One response of Ontario's farmers to information on water quality has been to initiate their own program, the Environmental Farm Plan, which has 23 modules by which the risk of environmental contamination can be assessed. Government policies for agriculture can be expected to influence farming practices. However, the literature suggests that the consequences of policies aimed at reducing environmental contamination are poorly understood, not least because the instruments used for implementation can have widely differing impacts. The need for discussions on the ethics surrounding the relationship between food producers and consumers with regard to environmental contamination is identified.     

A Comparison of Bacterial Indicators and Methods in Rural Surface Waters

The United States Environmental Protection Agency (USEPA) recommends the use of Escherichia coli (E. coli) and enterococci as indicators of enteric pathogens in fresh waters; however, fecal coliform analyses will remain important by virtue of the large amount of historic data collected in prior years. In this study, we attempted, in a real-world situation (i.e., a rural inland watershed in the Piedmont of South Carolina) to compare different bacterial indicators and methods to one another. We compared fecal coliforms, enumerated by membrane filtration with E. coli, enumerated by a commercialized enzyme substrate method and observed E. coli/fecal coliform ratios of 1.63 and 1.2 for two separate tests. In the same watershed, we observed an E. coli/fecal coliform ratio of 0.84 when we used the commercialized enzyme substrate method for both enumerations. Given these results, users of such data should exercise care when they make comparisons between historic membrane filtration data and data acquired through the use of the more modern enzymatic methods. Some sampling and side-by-side testing between methods in a specific watershed may be prudent before any conversion factors between old and new datasets are applied.     

采样时间对ANDERSEN采样器采样效果的影响

在室内用ANDERSEN生物粒子采样器进行了不同采样时间对采集空气细菌和真菌粒子浓度，粒数中值直径效果的研究，结果表明，在1－12min内，采集的空气细菌和真菌粒子浓度随采样时间的增加而减少，呈明显的负相关关系，相关系数分别为－0．903和－0．688，P值均大于0．05，另外，在采样过程中，空气真菌比细菌耐受采样空气冲击力的能力强，采样时间对空气细菌和真菌粒子的粒度分布和粒数中值直径的影响不明显。