降解SO_2功能菌的16S rRAN基因测序及降解特性

用低浓度SO2诱导驯化方法获得高效脱硫菌群,并用分离培养与16S rRNA基因测序技术相结合的方法鉴定菌群种属,分析驯化过程中种群结构的动态变化,同时研究分离纯菌种的脱硫性能。结果表明,从诱导驯化7 d和14 d菌液中分别分离出23株菌和22株菌,16S rRNA序列分析发现这些菌归属于13个种,其中有6个种（Rhodococcus erythropolis、Pseudomonas putida、Microbacterium oxydans、Sphingomonas koreensis、Acinetobacter junii、Acinetobacter johnsonii）对SO2-3有较强的降解能力,并在持续驯化过程中稳定的生长传代,降解产物以硫酸根为主,还有极少量的单质硫。与含混合菌的驯化菌液降解SO2-3的能力相比,单一脱硫菌的脱硫性能较弱。脱硫功能菌株及其基本特性的研究为微生物处理SO2烟气提供了丰富的菌源信息和理论基础。     

稠油降解微生物的筛选鉴定及其降解特性

从二连油田原油和油层水中筛选驯化出3株能够降解稠油的细菌DS1、DS2和DS3,通过16S rRNA基因序列比对发现DS1、DS2和DS3分别与溶血不动杆菌(Acinetobacter haemolyticus)、鹑鸡肠球菌(Enterococcus gallinarum)和耳炎短杆菌(Brevibacterium otitidis)相似度最高,分别为99%、99%和98%。研究结果表明,DS1对温度和pH有较强耐受性,DS3对盐度的适应性较好,2株菌最适的降解条件为温度35~40℃、盐度2%~5%(W/V)、pH为7~10。在5%的原油浓度下,复合菌对原油的30 d降解率达89.2%。经GC-MS分析,微生物降解作用后,除C29其他烃类几乎被全部降解。3株菌在7d内对500 g/L粘度为1 746 mPa·s(50℃)的稠油降粘率分别为49.1%、46.6%和49.0%,而复合菌对稠油的降粘效果高于单一菌株,其降粘率达到57.0%。     

两株稠油高效降解菌的筛选鉴定及其降解性能研究

从广州石化厂曝气池周围的油泥中筛选驯化出2株可以降解稠油的菌株GSO2和GSO7,经16S rDNA序列分析鉴定这两株菌均属于不动杆菌属(Acinetobacter sp.).通过摇瓶振荡实验,对GSO2和GSO7在以稠油为唯一碳源时的生长情况、降解率及环境条件对降解率的影响进行了研究.结果表明,菌株GSO2和GSO7...     

含油污泥中石油降解菌的分离及其降解特性

从渤海油田含油污泥中分离出3株石油烃降解菌,通过16S rRNA基因序列鉴定RS1、RS2和RS3分别为棒状杆菌、短杆菌和假单胞菌。经单因素实验确定,3株细菌对石油的最适降解条件分别为37℃、盐度3%、pH 8;32℃、盐度1%、pH 8;42℃、盐度1%、pH 6。降解实验结果表明,3株细菌30 d内对含油污泥中总石油烃的降解率分别为39.69%、31.13%和53.29%,而混合菌的降解效果明显高于单一菌株,降解率为58.08%;不同菌株对原油中不同组分的降解能力不同,其中,RS1对饱和烃的降解率最高,达20.74%,RS3对芳香烃的降解率最高,达到8.08%;GC-MS分析表明,混合菌对nC12~n-C34等正构烷烃均有明显降解,且对萘、苊、屈和苯并[b]荧蒽等多环芳烃的降解能力较强。     

报废发射药降解菌种选育及降解特性

通过驯化富集培养,从长期受发射药污染的土壤中分离筛选出能以发射药为唯一碳源并具有较高降解能力的微生物混合菌群,混合菌群对发射药样品COD去除率最高可达75.6%。经进一步分离纯化,获得了5株优势菌。实验表明混合菌群的降解能力优于各单一菌种,应以混合菌群为目标菌种。混合菌群最佳降解温度为30～35℃,最佳pH值为7.0。...     

集约化养猪废水SBR中17β-雌二醇高效降解菌的分离鉴定及其降解特性

从集约化养猪废水生物处理SBR的活性污泥中分离到3株高效降解17β-雌二醇(E2)的菌株,分别命名为ha、chs和hc。研究表明,这3株菌以E2为惟一碳源,在4 d内对初始浓度为1 mg/L E2的降解率为70%～95%。25℃条件下菌ha、chs和hc的一级反应动力学常数分别为0.0086、0.072和0.013。在温度为37℃时,3株菌的降解效率最高,在高浓度的氨氮和碱性pH的条件下,这3株菌均存在降解作用。其中,pH 9.05时,一级动力学常数菌ha降至0.0066,菌chs升至0.076,菌hc降至0.012。同时,在添加C源后,对降解有促进作用,并且C/N比在15∶1时降解效果较好。3株菌的一级反应动力学常数分别升到0.027、0.73和0.021。经16S rRNA基因序列分析鉴定为枯草芽孢肝菌(Bacillus subtilis)。     

石油降解菌群的筛选、构建及其降解特性研究

为了构建高效石油降解混合菌群,从潜江某油田采集8个石油污染土样(分别记为S1~S8)和2个石油污染水样(分别记为W3、W4),以石油为唯一碳源进行富集驯化培养;采用外观评分、石油降解率、石油3组分降解率、饱和烃中正构烷烃色谱分析等方法筛选石油降解优势菌群,构建石油降解混合菌群;采用正交试验研究混合菌群最佳降解条件。结果表明,富集的10个石油降解菌群中S3、S4、S5、S6、S8为优势菌群,培养30d后的石油降解率分别为21.67%、22.34%、27.23%、20.46%、19.99%;菌群W3、W4对石油乳化效果较好;混合菌群M3(S3+S4+S5+S8+W3+W4)为石油降解优势混合菌群,其最佳降解条件为35℃、pH7.60、含油率1.70%,在最佳条件下培养30d后,混合菌群M3对石油降解率达30.71%,比最优菌群S5的石油降解率提高了12.78%。     

高效氯氰菊酯降解菌群的结构分析及其降解特性研究

以连作10年以上的棉田土壤为材料,以高效氯氰菊酯为唯一碳源,驯化获得能稳定传代并持续降解高效氯氰菊酯的LZ1菌群,对菌群中可培养的细菌进行分离鉴定,最后对其降解高效氯氰菊酯的特性进行分析。结果表明,LZ1菌群中可分离、纯化优势菌株12株,经16SrRNA序列分析,其中10株与铜绿假单胞菌(Pseudomonas aeruginosa)相似性达99%,1株与无色杆菌(Achromobacter mucicolens)相似性达99%。高效氯氰菊酯最佳反应条件为高效氯氰菊酯初始质量浓度250mg/L、温度27℃、pH7.0、装样量200mL。在最佳反应条件下培养的LZ1菌群24h时对高效氯氰菊酯的降解率可达68.81%,132h时的降解率可达92.39%,且LZ1菌群对高效氯氰菊酯的4种异构体没有明显的降解特异性。     

一株微囊藻毒素降解菌的分离与鉴定

以水华蓝藻细胞中提取的微囊藻毒素为筛选物质,从太湖水华腐烂蓝藻中富集筛选出1株微囊藻毒素降解菌。该菌株革兰氏染色呈阴性,细胞细长杆状,菌落黄色,圆形,不透明,接触酶、氧化酶实验均呈阳性。16S rRNA基因序列的长度为1 416 bp(GenBank登录号为FJ976656)。系统发育树显示,该菌株与微嗜酸寡养单胞菌(Stenotrophomonas acidam-iniphila)的亲缘关系最近。通过菌株形态特征、生理生化特征和16S rRNA基因序列分析,将此菌株鉴定为微嗜酸寡养单胞菌,不同于已报道的微囊藻毒素降解菌属种。微囊藻毒素降解实验表明,该菌株5 d内将15.4 mg/L的微囊藻毒素完全降解,降解能力高于假单胞菌。     

一株DBP高效降解菌的分离、鉴定与降解性能

从镇江某垃圾站污染土壤中分离出1株能够以邻苯二甲酸二丁酯为唯一碳源和能源生长的细菌高效降解菌TM。经形态观察、生化鉴定、16S rRNA序列及系统发育分析,鉴定该菌株为变形假单胞菌(Pseudomonas plecoglossicida)。采用正交实验和单因素对照实验对这株菌株的降解条件进行优化,确定其最适生长条件为:温度30℃,p H=7.0。在最适降解条件下,其在72 h内对400 mg/L DBP降解率达到88.56%,为邻苯二甲酸二丁酯的高效降解菌。底物广谱性实验表明,该菌株邻苯二甲酸二辛脂(DOP)、邻苯二甲酸(2-乙基已基)酯(DEHP)都具有良好的降解能力,表明其具备良好的底物广谱性,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。     

Biodegradation of s-triazine herbicide atrazine by Enterobacter cloacae and Burkholderia cepacia sp. from long-term treated sugarcane-cultivated soils in Kenya

In this study soils from sugarcane-cultivated fields were screened for bacterial species capable of atrazine (6-chloro-N²-ethyl-N⁴-isopropyl-1,3,5-triazine-2,4-diamine) degradation due to long exposure of the soils to this herbicide. To enrich for atrazine degraders, Minimal Salt Medium containing atrazine as the sole N source and glucose as the C source was inoculated with soils impacted with this herbicide and incubated. Bacterial growth was monitored by measuring optical density. The degradation of atrazine was followed by measuring residual atrazine in liquid cultures over a given time period by high performance liquid chromatography. Bacterial strains isolated from the enrichment cultures were characterized by biochemical tests and identified by 16S rRNA gene sequencing. Two bacterial strains coded ISL 8 and ISL 15 isolated from two different fields were shown to have 94 and 96% 16S rRNA gene sequence similarity to Burkholderia cepacia respectively. Another bacterial sp., ISL 14 was closely related to Enterobacter cloacae with a 96% 16S rRNA gene sequence similarity. There was not much difference between the extents of atrazine degradation by the enrichment cultures with communities (79–82% applied amount) from which pure strains were isolated and the pure strains themselves in liquid cultures that showed a degradation of 53–83% of applied amount. The study showed existence of bacterial strains in different sugarcane-cultivated fields which can use atrazine as a nitrogen source. The bacterial strains isolated can be used to enhance the degradation of atrazine in contaminated soils where atrazine is still considered to be recalcitrant.     

Identification and methionine analog tolerance of environmental bacterial isolates selected on methionine analog containing medium

Methionine is the first limiting amino acid in poultry feed. Currently, methionine supplement is synthesized from an expensive chemical process requiring hazardous chemicals. Therefore, the objectives of this study were isolation of methionine producing bacteria from environmental samples and quantification of methionine production in these isolated bacteria. MCGC medium was selected as the isolation medium for methionine-producing bacteria by using Corynebacterium glutamicum ATCC13032 and Escherichia coli ATCC23798 as the positive and negative controls, respectively. Thirty-nine bacterial strains were obtained from environmental samples. Only strains A121, A122, A151 and A181 were able to tolerate up to 0.1% (w/v) of ethionine or norleucine. These isolated strains were identified by sequencing small subunit rRNA genes. The results revealed that bacterial strains A121, A122, A151and A181 were Klebsiella species, Acinetobacter baumannii, A. baumannii and Pseudomonas aeruginosa, respectively. When methionine production in strains A121 and A181 was quantitated, strains A121 and A181 generated methionine up to 31.1 and 124.6 μg/ml, respectively.     

菌源对多环芳烃降解菌的筛选及降解性能的影响

高效降解菌的筛选对利用生物修复技术有效去除环境中的多环芳烃具有重要意义。分别以石油污染土壤和焦化废水活性污泥为菌源,分离出芘降解菌和混合PAHs(菲、荧蒽和芘)降解菌共14株并对其降解性能进行对比研究。结果表明,筛选得到的菌株分别属于9个菌属,其中2种菌源共有的菌属为Mycobacterium sp.、Ralstonia sp.和Shinella sp.。芘和PAHs的高效降解菌(CP16和CM32)均属于分支杆菌属(Mycobacterium),来源于焦化废水活性污泥;菌株CP16对芘(50mg/L)的7 d降解率为74.99%,CM32对PAHs(菲50 mg/L、荧蒽和芘各10 mg/L)的7 d降解率为100%。因此,以焦化废水活性污泥为菌源更有利于获得高效的多环芳烃降解菌。     

基于功能基因表达的高氯酸盐与硝酸盐氮修复

为更好地研究环境中高氯酸盐离子(ClO-4)与硝酸盐氮(NO-3-N)混合污染的共同降解。选用pcrA、cld基因表征参与高氯酸盐降解的细菌,NirS基因表征反硝化细菌,16S rRNA基因表征整个细菌群落的活性。通过对高浓度硝酸盐氮与高氯酸盐混合污染降解体系内不同时间点不同种基因的表达分析,实时定量的反应复杂环境中混合污染物生物降解机理。结果表明,在外源添加足够的醋酸盐作为电子供体条件下,NO-3-N与ClO-4质量浓度比为5∶1时,硝酸盐氮的存在不会完全抑制ClO-4的降解,当NO-3-N降解完全时,可以加快ClO-4的降解过程。在有硝酸盐氮存在的混合降解体系内,pcrA和cld基因与ClO-4的浓度变化之间的相关性不是很高,证明该功能基因对复杂环境中特定生物群落的表征有一定局限性。     

The metabolism of neonicotinoid insecticide thiamethoxam by soil enrichment cultures,and the bacterial diversity and plant growth‐promoting properties of the cultured isolates

A soil enrichment culture (SEC) rapidly degraded 96% of 200 mg L^?1 neonicotinoid insecticide thiamethoxam (TMX) in MSM broth within 30 d; therefore, its metabolic pathway of TMX, bacterial diversity and plant growth‐promoting rhizobacteria (PGPR) activities of the cultured isolates were studied. The SEC transformed TMX via the nitro reduction pathway to form nitrso, urea metabolites and via cleavage of the oxadiazine cycle to form a new metabolite, hydroxyl CLO‐tri. In addition, 16S rRNA gene‐denaturing gradient gel electrophoresis analysis revealed that uncultured rhizobacteria are predominant in the SEC broth and that 77.8% of the identified bacteria belonged to uncultured bacteria. A total of 31 cultured bacterial strains including six genera (Achromobacter, Agromyces, Ensifer, Mesorhizobium, Microbacterium and Pseudoxanthomonas) were isolated from the SEC broth. The 12 strains of Ensifer adhaerens have the ability to degrade TMX. All six selected bacteria showed PGPR activities. E. adhaerens TMX‐23 and Agromyces mediolanus TMX‐25 produced indole‐3‐acetic acid, whereas E. adhaerens TMX‐23 and Mesorhizobium alhagi TMX‐36 are N₂‐fixing bacteria. The six‐isolated microbes were tolerant to 200 mg L^?1 TMX, and the growth of E. adhaerens was significantly enhanced by TMX, whereas that of Achromobacter sp. TMX‐5 and Microbacterium sp.TMX‐6 were enhanced slightly. The present study will help to explain the fate of TMX in the environment and its microbial degradation mechanism, as well as to facilitate future investigations of the mechanism through which TMX enhances plant vigor.     

一株苯酚降解菌的筛选及降解动力学特性

利用富集驯化的培养方法,从首钢焦化厂废水处理系统中的二沉池出水中,分离筛选出一株能够高效降解苯酚的菌株B3对其16S rDNA序列进行分析,并选择Monod方程和Andrews方程分别研究该菌在不同苯酚浓度条件下的降酚动力学模式。结果表明,B3为蜡状芽孢杆菌(Bacillus cereus);苯酚浓度较低时,苯酚对菌株的生长基本不产生抑制作用,用Monod模型对B3降酚动力学过程进行拟合,其动力学参数V max=0.03 h-1,K s=25.53 mg/L;苯酚浓度较高时,按照Andrews模型对B3降酚动力学过程进行非线性最小二乘曲线拟合,其动力学参数V max=0.08 h-1,K s=147.52 mg/L,K i=384.96 mg/L。根据动力学方程,推论菌株B3降解对于浓度238.30 mg/L的苯酚具有最佳降解效果。     

电解质种类对电催化氧化降解苯酚的影响

研究了不同电解质对有机物电催化氧化性能的影响。以高温热解法制备了Ti/SnO2+Sb2O3阳极,用SEM和XRD对电极结构进行了表征。以苯酚为目标有机物,考察了Na2SO4、NaCl和NaNO33种不同电解质对苯酚降解效果的影响。用循环伏安法研究了苯酚在不同支持电解质条件下的电化学行为。采用碘量法测定了在不同电解质溶液中氧化性物质的生成量。研究结果表明,电极的活性涂层主要由SnO2和微量的Sb2O3组成,均匀完整地覆盖住了Ti基体表面。以NaCl为支持电解质时苯酚降解效果明显优于用Na2SO4、NaNO3为支持电解质,并且苯酚的降解主要以电极表面电化学生成的HClO和ClO-的间接化学氧化为主。以Na2SO4为支持电解质时有利于降低和稳定槽电压。在3种电解质条件下,苯酚的降解均遵循一级反应动力学规律。在降解过程中NaCl溶液中生成的氧化性物质浓度最大,且随降解时间延长逐渐增大。     

超声波光催化协同降解对甲基苯磺酸水溶液的机理研究

采用超声波与光催化联合法对模拟废水中难生物降解的对甲基苯磺酸(4-TSA)进行降解实验研究,借助紫外光谱、红外光谱、质谱、气相色谱、高效液相色谱、化学需氧量和总有机碳的检测结果对反应机理进行了初步探讨.实验结果表明:超声波和光催化之间存在着协同效应;当溶液初始质量浓度30 mg/L,光催化剂TiO2投加量为100 mg...     

Zero valent iron mediated degradation of the pharmaceutical diazepam

Parameters that influence the zero valent iron mediated degradation of the pharmaceutical diazepam (DZP) were evaluated including the iron concentration and its pre-treatment, the effect of complexation with EDTA and oxic versus anoxic condition. It was observed that acid pre-treatment of iron particles is important for degradation efficiency and that H₂SO₄ is a better choice than HCl, resulting in higher degradation of DZP. Under oxic conditions, the degradation of DZP achieved 96% after 60 min using Fe⁰ (25 g L⁻¹) pre-treated with H₂SO₄ in the presence of EDTA (119 mg L⁻¹), while mineralization achieved around 60% after the same time. Under anoxic conditions, degradation occurred, however at lower extent, achieving 67% after 120 min. The addition of EDTA improved the treatment efficiency in 20% leading to 99% DZP degradation after 120 min. The first intermediates formed during DZP degradation were identified using LC/MS analysis and revealed the formation of mono- and di-hydroxylated products from DZP during Fe⁰/EDTA/O₂ degradation, which evidences that OH was the main oxidizing species formed in this process.