一株高效MC-RR降解菌的分离鉴定及其降解特性

为了得到一株具有降解微囊藻毒素-RR(MC-RR)特性的产芽孢菌株,采用加热富集芽孢菌的方法,从太湖分离到一株MC-RR降解菌CM1,该菌对MC-RR具有强烈的降解特性。通过形态学特征、生理生化特征及16S rDNA序列分析鉴定该菌株属于耐硼赖氨酸芽孢杆菌(Lysinibacillus boronitolerans)。通过研究温度和pH值对菌株CM1降解MC-RR能力的影响,发现菌株CM1在60 h将MC-RR由12.77μg/mL降解到1.67μg/mL,降解率达86.90%,最适降解温度为37℃,最适pH值为7.0。CM1菌株的胞外物质和胞内物质均能降解MC-RR,但胞内物质具有更强烈的降解特性,12 h可以将7.27μg/mL的MC-RR完全降解。为丰富MC-RR降解菌纯菌种研究以及在去除水体中MC-RR应用研究方面提供了理论基础。     

一株施氏假单胞菌Pseudomonas stutzeri DN-LWX19的脱氮性能

从缺氧生物滤池筛选纯化得到一株具有高效反硝化能力的异养菌DN-LWX19,通过形态观察、生理生化特性及16S rDNA同源性分析,确定该菌株为施氏假单胞菌(Pseudomonas stutzeri).脱氮性能研究结果表明,菌株DN-LWX19在NO3--N初始浓度为120.43 mg/L的试管培养基中,60 h对NO3--N去除率达90％,NO2--N积累浓度仅0.05 mg/L.以添加适量乙酸钠的实际污水处理二级出水为液体培养基,研究DN-LWX19在初始NO3--N浓度约为30.00 mg/L时的脱氮效果,当碳氮比(COD/NO3--N)为5∶1时,菌株DN-LWX19在32 h对NO3--N去除率为100％,但是有NO2--N的积累(7.00 mg/L),且至72 h无明显变化;当碳氮比为9∶1时,菌株DN-LWX19在32h对NO3--N的去除率为100％,且无NO2-N的积累.     

土霉素生产废水生物处理装置中微生物群落结构特征解析

抗生素对细菌具有强抑制作用,从而会影响废水生物处理系统中的微生物群落结构。在用定量PCR方法对土霉素生产废水处理装置(进水中土霉素浓度为1 662.1±248.6μg/L)中的细菌16S rRNA基因和真菌18S rRNA基因的含量进行比较的基础上,利用16S rRNA基因克隆文库方法对污泥中的细菌群落结构进行了详细解析。定量PCR结果显示,土霉素废水活性污泥中真菌(18S rRNA)/细菌(16S rRNA)基因的拷贝数比例高达1.2,明显较高于非抗生素肌苷废水活性污泥中的比例1.52×10-6,表明真菌对于土霉素废水中有机物的去除可能发挥重要作用。细菌克隆文库分析结果显示,Alpha变形菌和Beta变形菌是主要的优势菌,比例分别为23.7%和22.0%,其次是酸杆菌(17.0%)和拟杆菌(11.9%)。     

鄱阳湖老爷庙水域细菌群落组成分析

通过提取鄱阳湖老爷庙水域水体细菌总DNA, 构建细菌16SrRNA基因文库和序列测定等手段,以期揭示鄱阳湖老爷庙水域的细菌群落组成并探讨细菌多样性与湖泊水体理化参数之间的关系。研究结果认为：来自老爷庙水域的2006年10月（PN06 10）和2007年5月 (PN07 5) 的细菌文库中的180个阳性克隆产生了66个细菌分类操作单位（OTUs）,这些细菌主要分属于：变形菌Alpha 纲,Beta 纲,Gamma 纲,Epsilon 纲,拟杆菌门,放线菌门,浮霉菌门,酸杆菌门和OP10等9大类型。2006年10月老爷庙水域的优势菌群为Beta 变形菌;2007年5月优势菌群为Gamma 变形菌和拟杆菌,表明鄱阳湖细菌组成在不同的季节显著不同。进一步系统发育分析表明：大部分细菌的最相似序列来源于淡水,湖泊和土壤的未培养细菌,且部分细菌与环境污染物降解有关     

A novel acidophile community populating waste ore deposits at an acid mine drainage site

Waste ore samples （pH 3.0） were collected at an acid mine drainage （AMD） site in Anhui, China. The present acidophillc microbial community in the waste ore was studied with 16S rRNA gene clone library and denaturing gradient gel electrophoresis （DGGE）. Eighteen different clones were identified and affiliated withActinobacteria, low G ＋ C Gram-positives, Thermomicrobia, Acidobacteria, Proteobacteria, candidate division TM7, and Planctomycetes. Phylogenetic analysis of 16S rRNA gene sequences revealed a diversity of acidophiles in the samples that were mostly novel. It is unexpected that the moderately thermophilic acidophiles were abundant in the acidic ecosystem and may play a great role in the generation of AMD. The result of DGGE was consistent with that of clone library analysis. These findings help in the better understanding of the generation mechanism of AMD and in developing a more efficient method to control AMD.     

Detection of dioxygenase genes present in various activated sludge

GOAL, SCOPE AND BACKGROUND: Activated sludge from refineries contains various microorganisms that could utilize aromatics under aerobic conditions due to the oxygenase enzymes. Dioxygenase enzymes are oxygenases, which are involved in the ring cleavage step of aromatic hydrocarbons. In this study, the selected catabolic loci involved in ring cleavage have been monitored in the activated sludge samples at different time intervals. The investigation of the dioxygenase genes in the Effluent Treatment Plants (ETPs) and evaluation of their presence at different time points provides a clue for the aromatic utilizing potential of the inherent microbial flora. METHODS: The catabolic gene loci pheB, xylE, tod-isp, bed and nahG responsible for the enzymes catechol 1,2-dioxygenase, catechol 2,3-dioxygenase, toluene dioxygenase-iron-sulphur protein component, benzene dioxygenase and naphthalene dioxygenase were used respectively. The time dependent change in eubacterial population was demonstrated by the amplification of 16S rDNA product, followed by restriction digestion. The template DNA was obtained from the activated sludge collected from ETPs. The supporting physiological data for the overall performance of sludge was developed using respirometric analysis. The on-site COD and MLSS analysis for ETP was used in final evaluation. The study was carried out with samples collected from three different ETPs and also from a selected ETP at different time intervals. RESULTS AND DISCUSSION: The respirometric studies were carried out with phenol, catechol, toluene, and naphthalene to arrive at the target genotypes for further study by PCR protocol. The respirometric analysis coupled with the COD and MLSS analysis represented the physiological capacity of the various sludges. Initially, the tracking protocol was optimized by using different sludge samples, which were collected from refineries. The selected genotypes were amplified and their presence has been confirmed using Southern analysis. The gene loci tod-isp, bed and xylE were commonly observed at various time intervals of the sludge from the same source. The gene loci pheB and nahG were found to be relatively rare. CONCLUSION: The 16S rDNA PCR products after restriction digestion produced different DNA fingerprint patterns, suggesting that the microbial community composition was diverse in the three sources. Similarly, the presence of the catechol 2,3-dioxygenase, benzene dioxygenase and toluene dioxygenase genes confirmed the aromatic degrading potential in the various sludges. The probes could not pick the nahG and pheB genes. However, the respirometeric assay suggested that the oxidative capacity to use naphthalene as a substrate exists. RECOMMENDATION AND PERSPECTIVE: Our study of the diversity at various time points from the ETP provided an overview of the shifts of the catabolic composition of the sludge. This also depends on the influential parameters like the incoming pollutant level and the environmental conditions that are prevailing and often changing from time to time. The results of direct DNA extraction and PCR amplification do reflect the relative abundance of a particular catabolic genotype, which could be used to monitor the efficiency of treatment.     

1株溶藻菌的部分生物学特性及溶鱼腥藻作用

从淡水湖泊(武汉东湖)水样中成功筛选出1株具有溶藻特性的细菌,编号为A01.显微镜和电镜观察结果表明,菌株A01形态为杆状,长约1.5μm,宽约0.45μm,无鞭毛结构.革兰氏染色及16S rDNA的分子鉴定结果表明,该菌呈革兰氏阴性,属于不动杆菌属(Acinetobacter sp.).溶藻实验结果表明,菌株A01能有效溶解鱼腥藻(Anabaena eucompacta),向对数生长的鱼腥藻藻液中加入A01培养上清或菌体、并培养7 d后,鱼腥藻培养液的叶绿素a去除率分别为77%和61%.显微观察结果表明,与菌株A01的培养上清共培养3 d后的鱼腥藻细胞几乎都被破坏,而与菌体共孵育5 d后的鱼腥藻细胞才有明显裂解.这些结果表明,不动杆菌菌株A01的溶藻作用主要与其培养上清中的有效成分有关,不动杆菌菌株A01可分泌能有效溶解鱼腥藻的活性物质.     

1株高效BBP降解菌的分离与特性研究

从湖北省荆沙河泥样中富集培养分离得到了1株能够以邻苯二甲酸丁基苄基酯为唯一碳源和能源生长的细菌并命名为HS-B1.采用形态学、生理生化和16S rDNA序列分析对其进行了鉴定,发现HS-B1是1株杆状、需氧、革兰氏阴性细菌,接触酶呈阳性反应,氧化酶呈阴性反应,不产硫化氢气体,且该菌的16S rDNA序列与琼氏不动杆菌(Acinetobacter junii)的相似性高达99%.因此初步鉴定该菌株为不动杆菌(Acinetobacter sp.).摇瓶实验表明,菌株HS-B1生长和BBP降解的最适培养条件为35℃,pH 8.0.采用0.10 mmol.L-1非离子型表面活性剂吐温-80提高了BBP在水溶液中的表观溶解度,发现在最适培养条件下,HS-B1能够在48 h内将浓度为1 000 mg.L-1BBP完全降解,证明是一株高效降解菌.底物广谱性实验中,菌株HS-B1也能够有效利用DMP、DEP、DBP等邻苯二甲酸酯类化合物,说明该菌株在处理邻苯二甲酸酯类化合物的污染治理中有独特的应用潜力.     

温度分化对APBR反应器性能及产甲烷菌群落的影响

为了研究温度分化对固定床厌氧反应器(anaerobic packed bed reactor,APBR)牛粪发酵处理效果及产甲烷菌群落的影响,反应器发酵温度从室温(22℃±1℃)阶梯式分化到低温(15℃±1℃)、中温(37℃±1℃)和高温(55℃±1℃).温度变化的过程中,温度越高COD(chemical oxygen demand)去除率和日总产气量越高,分化后COD去除率分别为25%、45%、60%,相应的日产气量为2.3、4.0、8.5 L·d-1,但是甲烷含量基本保持不变(~60%);温度突然变化造成挥发性脂肪酸含量骤然增加,并处于波动状态.16S r RNA基因克隆文库法分析表明,室温时包含广古菌门中的常见重要产甲烷菌MBT(甲烷杆菌目)、Mst(甲烷鬃菌科)、Msc(甲烷八叠球菌科)和MMB(甲烷微菌目),以及嗜热菌,也有少部分泉古生菌门,发酵温度分化后,产甲烷菌多样性减少,中温条件下产甲烷菌种类相对较少.定量PCR表明Mst、MMB和Msc总基因浓度都有所减少,并且温度越高减少越多,各菌数量相对比例变化较大,但Mst仍为优势产甲烷菌.     

一株耐镉链霉菌的筛选、鉴定与基本特性分析

微生物在重金属污染治理中具有重要作用.采用微生物纯培养技术从镉污染土壤中分离获得一株在液体培养基和固体培养基中能够分别耐受45 mmol·L~(-1)和50 mmol·L~(-1)Cd~(2+)的细菌,通过形态学、生理生化及分子鉴定,初步鉴定该菌株属于链霉菌(Streptomyces sp.),命名为Streptomyces sp.strain Cd TB01.进一步实验结果表明,耐镉链霉菌Streptomyces sp.strain Cd TB01的优化培养条件为:马铃薯蔗糖培养基,在250m L的三角瓶中装液量为90 m L,培养温度30℃,初始pH=6.0,接种量6.0%,NaCl质量分数0%;湿菌体吸附Cd~(2+)的优化条件为:温度30℃,pH=8.0,NaCl质量分数1.0%,Cd~(2+)浓度500 mg·L~(-1),吸附率为44.78%;干菌粉吸附Cd~(2+)的优化条件为:温度30℃,pH=9.0,NaCl质量分数0%,Cd~(2+)浓度100 mg·L~(-1),吸附率达到70.45%.说明链霉菌Streptomyces sp.strain Cd TB01在重金属污水处理中具有广阔的应用前景.