假单胞菌P12对菲的降解

从武汉石油化工厂的活性污泥中,分离到一株可以以菲为唯一碳源和能源的假单胞菌P_(12)该菌经靛蓝产生法测定有双加氧酶,在菲无机盐培养基中生长时,有3-菲酚物质积累,经检测有一条质粒带。用丝裂霉素C消除质粒后的菌落,失去了降解菲的能力,说明P_(12)对菲的降解功能是由质粒控制的。     

假单胞菌磷代谢特性的研究

本文考察了处理效果良好的循序间歇式废水生物脱氮除磷试验装置内活性污泥优势菌——假单胞菌(Pseudomonas sp.)的磷代谢特性。试验结果表明,在好氧条件下,以乙酸盐为基质培养时,向培养基内滴加H_2SO_4可导致假单胞菌产生磷释放现象,滴加NaOH或NaHCO_3时,则发生过量摄磷现象,且加NaOH较加NaHCO_3所引起的磷摄取量大。另外,当以乙酸盐为基质时,假单胞菌于好氧培养过程中能明显除磷,其效果与厌氧-好氧培养过程相近。     

己烯雌酚降解菌株沙雷氏菌的分离鉴定及其降解特性

利用具有降解己烯雌酚(diethylstilbestrol,DES)特性的功能微生物来降解DES、有望实现环境中DES的有效去除,然而迄今关于降解DES的功能菌株及其降解特性的报道很少.本研究通过选择性富集培养,从某污水处理站活性污泥中分离获得1株具有DES降解特性的细菌(菌株S).经形态观察、生理生化试验及16S rDNA序列同源性分析将菌株S鉴定为沙雷氏菌属(Serratia sp.)细菌.菌株S好氧生长,30℃、150 r·min-1摇床培养7 d后,对无机盐培养基中DES(50 mg·L-1)的降解率达68.3%.通过摇瓶实验,优化了菌株S生长和降解DES的最适环境条件:温度30℃,底物浓度40～60 mg·L-1,pH 7.0,接种量5%,盐添加量0 g·L-1,装液量10 mL(100 mL三角瓶).     

Isolation, identification and characterization of an algicidal bacterium from Lake Taihu and preliminary studies on its algicidal compounds

In an effort to identify a bio-agent capable of controlling cyanobacterial blooms, we isolated a bacterial strain, A27, which exhibited strong algicidal activity against the dominant bloom-forming species of Microcystis aeruginosa in Lake Taihu. Based on 16S rRNA gene sequence analysis, this strain belongs to the genus Exiguobacterium. This is the first report of an algicidal bacterial strain belonging to the genus Exiguobacterium. Strain A27 exhibited algicidal activity against a broad range of cyanobacteria, but elicited little or no algicidal activity against the two green algal strains tested. The algicidal activity of strain A27 was shown to be dependent on the density of the bacteria and to have a threshold density of 1.5× 10⁶ CFU/mL. Our data also showed that the algicidal activity of strain A27 depended on different growth stages of Microcystis aeruginosa (exponential ≈ lag phase > early stationary) rather than that of the bacterium itself. Our results also suggested the algicidal activity of strain A27 occurred via the production of extracellular algicidal compounds. Investigation of the algicidal compounds revealed that there were at least two different algicidal compounds produced by strain A27. These results indicated that strain A27 has great potential for use in the control of outbreaks of cyanobacterial blooms in Lake Taihu.     

海洋菌株y3的分离鉴定及其异养硝化-好氧反硝化特性

从胶州湾海底沉积物中筛选出1株高效的海洋异养硝化-好氧反硝化细菌y3,经形态学观察、生理生化实验和16S rRNA基因序列分析,确定该菌株为假单胞菌属(Pseudomonas sp.).对其在实际含氮海水中的脱氮实验结果表明,菌株y3的最佳碳源为柠檬酸三钠,最适p H为7.0,最适C/N为13;菌株均能以NH4Cl、Na NO_2和KNO_3为唯一氮源进行反应,20 h后其去除率分别为98.69%、78.38%和72.95%,在硝化过程中几乎没有亚硝酸盐和硝酸盐的积累.以不同比例混合两种氮源反应20 h,当NO~-_3-N∶NO~-_2-N分别为2∶1、1∶1和1∶2时,脱氮率分别为99.56%、99.75%和99.41%;当NH~+_4-N∶NO~-_3-N分别为2∶1、1∶1、1∶2时,脱氮率均为100%;当NH~+_4-N∶NO~-_2-N分别为2∶1、1∶1、1∶2时,脱氮率分别为90.43%、92.79%和99.96%,多高于单一氮源的情况.该菌株具有较好的高盐废水脱氮处理效能.     

Cu2+、Cd2+、Zn2+对两种单胞藻的毒害作用

分别用不同浓度 (c =0 .0 1～ 2 .34mmol/L)的Cu2 + 、Cd2 + 、Zn2 + 处理亚心型大扁藻 (Plztymonassp.)和小球藻(Chlorelavulagris) ,观察了重金属离子对其生长、呼吸及其被富集的情况 .结果表明 :① 3种离子的毒性强度的顺序为Cu2 + >Cd2 + >Zn2 + ;亚心型大扁藻的耐受力大于小球藻 ;②Cu2 + 对生长的抑制最强 ,两种藻的c(EC50 ,72h)分别为 0 .2 11mmol/L和 0 .2 89mmol/L ;Cd2 + 对生长的抑制稍弱 ,两种藻的c(EC50 ,72h)分别为 0 .4 38mmol/L和 0 .2 4 1mmol/L ;Zn2 + 对生长的抑制最弱 ,其c(EC50 ,72h)分别为 0 .75 4mmol/L和 0 .30 8mmol/L ;③在c(EC50 )毒害浓度下 ,两种单胞藻均提前进入生长静止期 ,缩短了种群生长周期 ;呼吸作用先增强后降低 ;④在c(EC50 )毒害浓度下 ,两种藻对Cu2 + 、Zn2 + 的富集量为 4 5 82～ 4 12 83.7mgkg-1,对Cd2 + 的富集量 5 0 0～ 2 72 3.6mgkg-1.图 2表 3参 8     

Role of Acinetobacter sp. in arsenite As(III) oxidation and reducing its mobility in soil

Microbial arsenite oxidation was observed by Acinetobacter sp. XS21, this strain oxidised arsenite As(III) up to 80?mM within 48–72?h of incubation. The present strain XS21 oxidised As(III) at a very high concentration in a shorter interval of time than any of the previous reported microbes. Further, XS21 was applied to the soil to observe its ability in reducing the mobility of As(III), and we found that Acinetobacter sp. XS21 efficiently removed arsenite from soluble-exchangeable fraction and removed 70% of the arsenite as compared to control. This feature makes it a potential candidate for bioremediation. Arsenic-resistant bacteria with strong As(III)-oxidising ability may have potential to improve bioremediation of As(III)-contaminated sites. To understand their basis of resistance and transformation we found the As(III) oxidase gene using degenerate primer and amplified ～550?bp of aioA gene. Amplified aioA gene sequence exhibiting 52% identity in terms of gene and deduced protein sequence to Uncultured bacterium, and Achromobacter sp. arsenite oxidase of larger subunit. Arsenite oxidase, an enzyme, was also observed in this isolate, which may provide a resistance and transforming ability. This bacterium was identified as Acinetobacter sp., by sequencing 16s rRNA gene sequence analysis.     

一株除草剂氰氟草酯降解菌的分离鉴定与降解特性

氰氟草酯(Calofop-buty1)是一种芳氧苯氧羧酸酯类除草剂,其迁移、转化和分解等行为对环境及人类健康具有潜在危害.为了解其微生物代谢机制,从长期使用氰氟草酯的稻田土壤中分离到1株氰氟草酯降解菌株,命名为QDZ-B.菌株QDZ-B的16S rDNA基因序列长度为1 400 bp,在RDP数据库比对结果表明其与寡养食单胞菌属菌株的同源性最近,与模式菌株嗜麦寡养食单胞菌Stenotrophomonas maltophilia(AB008509)的同源性为99.8%.根据表型特征、生理生化特性和16S rDNA序列同源性分析,将菌株QDZ-B鉴定为寡养单胞菌属(Stenotrophomonas sp.).接种量为5%时,菌株QDZ-B在基础盐液体培养基中5 d对100 mg L-1氰氟草酯的降解率约为88.2%.菌株QDZ-B的降解效果与接种量成正相关,但接种量大于5%时,降解效率趋于平稳.菌株QDZ-B降解氰氟草酯的最适温度为30℃,最适pH为7.0.通过质谱分析鉴定了3个菌株QDZ-B降解氰氟草酯的代谢产物,分别为氰氟草酸、氰氟草酰胺和2-氟-3-对-乙氧基苯氧基苯酰胺.     

Citrobacter sp. LW-3对偶氮染料甲基橙的降解脱色特性研究

从长期受染料污染的土壤中分离出一株能对甲基橙高效降解脱色的柠檬酸盐杆菌Citrobacter sp.LW-3.菌株LW-3在添加了0.5%(g/100 mL)葡萄糖的MSM-1培养基中,16 h使100 mg·L-1甲基橙降解掉90.56%.该菌株对甲基橙降解脱色可在完全好氧条件下,脱色与木质素过氧化物酶、NADH-DCIP原酶、核黄素还原酶有关.菌株LW-3降解甲基橙的适宜温度较广,20~40℃24 h均能使超过80%的甲基橙降解脱色,适宜pH范围为6.0~8.0.通气量对菌株LW-3影响较小,24 h各装液量组(25~200 mL)甲基橙均能降解近90%.同时,菌株LW-3具有较广的染料降解谱,3 d内可使20 mg·L-1另3种偶氮染料、两种三苯甲烷类染料和一种蒽醌类染料很好脱色.菌株LW-3在染料废水的生物处理方面有较强的实际应用价值.     

微生物絮凝剂生产菌T1的鉴定及其对生活污水絮凝特性

从活性污泥中分离筛选絮凝剂产生菌,得到一株对高岭土悬浊液具有较高絮凝活性的微生物絮凝菌T1.根据菌株的生理生化鉴定以及16S r DNA基因序列分析,确定该菌株为芽孢杆菌(Bacillus sp),该菌的絮凝活性物质分布在发酵液上清液中.通过正交实验确定最佳生活污水絮凝条件为絮凝剂投加量5%,污水p H值7.0,助凝剂Ca Cl2投加量为2%,在此条件下,T1发酵上清液对生活污水的絮凝率为83.85%.