镉对稻田土壤典型微生物种的胁迫生理毒性

以水稻田土壤中典型的单种微生物为实验材料,采用纯培养方法,从个体水平上全面探讨了重金属镉胁迫对稻田土壤典型微生物的的生长、活性以及生化过程的生理毒性影响。研究表明:不同微生物纯培养对镉胁迫的敏感程度不同,G 较G-对Cd2 更为敏感,表现为世代时间缩短,最高菌浓度下降。固氮菌对Cd2 非常敏感,当Cd2 质量浓度为0.2mg·L-1时即完全抑制菌体增殖。同时,外源镉强烈的抑制作为稻田土壤中功能微生物的厌氧固氮菌及产甲烷细菌的生物活性,各菌种镉胁迫下细菌细胞内可溶性蛋白、还原糖、核酸质量浓度都在低质量浓度镉胁迫时有所增加;随着镉质量浓度的增加,细菌细胞内各种物质的质量浓度开始减小,以减慢细胞代谢速度,增强对镉胁迫的适应力;各种物质的质量浓度变化趋势为可溶性蛋白>还原糖>核酸,R.eutrophaDKC1细胞内含物质量浓度基本保持稳定。结果可在一定程度上说明镉对微生物的毒性效应,且能在早期较灵敏地指示污染的影响,作为稻田土壤环境受到污染胁迫的细胞生化指标具有一定可行性。     

Distribution of Poly(β-propiolactone) Aerobic Degrading Microorganisms in Different Environments

The distribution of degading microorganisms of high molecular weight poly(-propiolactone) (PPL), whose individual structural units are similar to those of poly(-hydroxybutyrate) (PHB) and poly(€-caprolactone) (PCL), was examined. Despite the fact that PPL is a chemosynthetic polymer, many kinds of PPL-degrading microorganisms were found to be distributed as resident populations widely in natural environments. A total of 77 strains of PPL-degrading microorganisms was isolated. From standard physiological and biochemical tests, at least 41 strains were referred to as Bacillus species. Microbial degradation of fibrous PPL proceeded rapidly in some enrichment cultures but was not as complete as that of PHB. Most of the isolated PPL-degrading microorganisms were determined to be PCL degraders and/or PHB degraders. Therefore, it can be assumed that mostly PPL is recognized by the microorganisms as PHB or another natural substrate of the same type as which PCL is regarded. Microbial degradation of PPL was confirmed by some Bacillus strains from type culture collections. The similarity of microbial degradation between PPL and PCL was found to be very close.     

聚硫氯化铝絮凝效果及在水处理中的应用

采用聚硫氯化铝（ＰＡＣＳ）为絮凝剂进行废水处理试验,对其絮凝效果及影响因素进行了研究,试验结果表明,ＰＡＣＳ的ＳＯ４＾２－含量,碱化度,投加量和水的ｐＨ对絮凝效果有影响,当Ａｌ＾３＋／ＳＯ４＾２－（摩尔比）为１４￣１６,碱化度为６５％￣７０％,ｐＨ为６￣９、ＰＡＣＳ投加量为２￣４ｍｇ／Ｌ时,絮凝效果最佳,试验结果还表明,ＰＡＣＳ比聚氯化铝（ＰＡＣ）的絮凝效果好。     

聚丙烯酰胺类絮凝剂的制备及应用研究

为了研究絮凝效果与絮凝剂分子结构的关系,实验中制备了聚丙烯酰胺（ＰＡＭ）、阳离子化聚丙烯酰胺（ＣＰＡＭ）和部分水解聚丙烯酰胺（ＰＨＰ）,将其分别与ＦｅＣｌ３复配后处理钻井废水。实验探讨了絮凝剂的分子量、ＰＨＰ的水解度及阳离子度对絮凝作用的影响。实验结果表明：ＰＡＭ、ＣＰＡＭ、ＰＨＰ与无机混凝剂复配使用处理钻井废水时,最佳分子量是５００万,处理效果依次为ＰＨＰ＞ＰＡＭ＞ＣＰＡＭ。     

絮凝浮选剂PS-01的研究

为了提高油田采油（气）污水处理能力,胜利油田开发研制出新型絮凝浮选剂ＰＳ－０１,以聚合铝为主,配以常用的助凝剂二氧化硅气溶胶,工业用硫酸镁等,按比例混合在一起配置而成。在试验中将它们与油田内广泛使用的絮凝浮选剂ＳＧ－０１,ＪＸ－０１,ＮＡ－１等进行比较。结果表明：ＰＳ－０１絮凝浮选剂的原料来源广泛,合成工艺简单,易于操作;对采油（气）污水处理效果好,加药量少,处理成本低;应用的ｐＨ范围较宽,反应迅速,可缩短混合反应时间;适用性强,低温时效果不受影响;对投药设备的腐蚀性小,性质稳定,无沉淀产生;同时各种原料的不同配比对絮凝浮选效果影响很大,要控制好比例。     

影响微生物絮凝剂生成的条件研究

从污水中筛选到了一株絮凝活性较好的絮凝剂产生菌 ,分别研究了碳源、氮源、供氧量、培养温度等条件对其产絮凝剂的影响。结果表明 ,葡萄糖、淀粉是较好的碳源 ,蛋白胨等有机氮作氮源较好 ,供氧量较大有利于产絮凝剂 ,最适宜培养温度为 30℃ ,最佳pH为 6 .5～ 7.5。     

微生物絮凝剂的特性研究及其进展

微生物絮凝剂具有高效、安全、不污染环境等特点，已日益受到重视，综述了微生物絮凝剂的研究发展和应用现状，对絮凝性微生物的培养及絮凝剂的特性进行总结，并展望了其发展趋势。     

中小城市污水化学强化一级处理分析

在中小城市污水处理特点的基础上，分析了适宜中小城市污水处理的投融资方式，化学强化一级处理的工艺方法、效果及存在的问题。     

胞外聚合物合成与应用研究概况

介绍了胞外聚合物絮凝剂研究与发展概况;讨论胞外聚合物絮凝剂的结构、性能及作用机理;重点介绍了胞外聚合物絮凝剂产出、絮凝条件以及应用的研究;胞外聚合物絮凝剂研究的发展趋势。     

Volatile metabolites from indoor molds grown on media containing wood constituents

Since volatile mold metabolites are used for the detection of mold growth in buildings, it was interesting to determine whether different indoor mold species show different affinity for the major components of wood, a common building material. Growth and volatile metabolites were studied when Aspergillus versicolor, Penicillium chrysogenum, and P. palitans were grown on laboratory substrates containing the major wood constituents cellulose, xylan and lignin. Microbial volatile organic compounds (MVOCs) were characterized by thermal desorption/gas chromatography/mass spectroscopy. Growth and volatile metabolites varied considerably and there appeared to be complementary substrate specificities for P. chrysogenum, and P. palitans grown on cellulose and xylan. The failure of A. versicolor to produce characteristic MVOCs when grown on media containing wood constituents suggests that systems using volatile metabolites to detect microbial growth in buildings may be fundamentally unreliable for the detection of this species.