异育银鲫(Carassius auratus gibelio)源醋酸钙不动杆菌表型及分子鉴定

采用常规的培养特征、理化特性及分子生物学的方法,对从濒死异育银鲫(Carassius auratus gibelio)血液中分离到的菌株SY-1进行了致病性、表型生物学、分子生物学及药敏试验的系统研究。结果表明,该菌株在盐度5—30、pH6—8,温度10—42℃的LB液体培养基中均能生长,具有脲酶。该菌株16SrRNA基因序列(Gen Bank登录存取号:JX164201,长度1435bp)与其它不动杆菌属菌的16SrRNA基因同源性相似性在99%—100%之间,构建系统发育树确定该菌株为醋酸钙不动杆菌(Acinetobacter calcoaceticus)。人工回感可导致异育银鲫死亡。药敏试验结果显示:对恩诺沙星、强力霉素、萘啶酸、复方新诺明、氧氟沙星等10种抗生素敏感;对羧苄青霉素、诺氟沙星、大观霉素、卡那霉素、四环素等14种抗生素中度敏感;对氨苄西林、苯唑西林、林可霉素、万古霉素、氟苯尼考等15种抗生素耐药。     

Scum in Activated Sludge Plants: Impact of Non‐filamentous and Filamentous Bacteria

Excessive scum production is a widespread phenomenon in present activated sludge wastewater treatment. The question how foaming is initiated and stabilized is still unanswered. Hydrophobic wastewater ingredients and surface active material such as synthetic surfactants are discussed among others as major causative agents for scum production. Focusing on biological impacts non‐filamentous bacteria isolated from scum turned out to contribute to flotation by both cell surface hydrophobicity and emulsification activity, depending on the prevailing substrate and milieu conditions. The biological characterization of scum based on microscopic sludge investigation of conspicuous microorganisms resulted in a significant shift of filamentous and non‐filamentous organism populations with Gram‐positive bacteria prevailing in present nutrient removal plants as compared to the situation ten years ago. Their hydrophobic cell surface is supposed to support adherence and stabilization of interfaces and thus promote sludge flotation. In scum six types of filamentous bacteria turned out to be numerous: Microthrix parvicella and nocardioform actinomycetes, both of them being enriched in the scum fraction, moreover Nostocoida limicola and Eikelboom types 0041/0675, 1851, and 0092. Possible interactive mechanisms between non‐filamentous and filamentous scum bacteria and their selection factors are discussed in order to contribute to a better understanding of scum formation and to provide efficient troubleshooting measures.     

不动杆菌属菌株WX-19还原Cr（Ⅵ）与降解苯酚特性

从制革废水中筛选到1株既能还原Cr（Ⅵ）又能降解苯酚的不动杆菌属（Acinetobacter）菌株WX-19。菌株降解苯酚和还原Cr（Ⅵ）的最适温度为30℃,最适pH为7.0～8.0。0.2～0.5 mol/L NO3-、SO42-和Cl-能够促进WX-19的生长及其对Cr（Ⅵ）的还原。利用PCR、克隆和基因测序的方法从WX-19中检测到苯酚羟化酶基因（GenBank No.JF730215）,与Pseudomonas sp.DHS3Y的苯酚羟化酶基因的同源性为88.5%。在含5 mg/LCr（Ⅵ）的基础盐培养基中,菌株WX-19可以利用苯酚为唯一碳源生长,并还原Cr（Ⅵ）;在含有葡萄糖的基础盐培养基中,添加苯酚有利于菌株WX-19的生长和Cr（Ⅵ）还原。