Pseudomonas S2-3菌株对Cr(Ⅵ)的耐受性及去除

针对分离得到的Cr(VI)耐受菌株S2-3进行了基本生长特征、16S rRNA序列分析、Cr(VI)对菌株生长影响、菌株生长代谢与铬的去除的关系等研究。结果表明:该菌株属于假单胞菌,与Pseudomonas chlororaphis(Z76673)相似性最高(99.8%);Cr(VI)对菌株生长有着明显的抑制作用,其耐受上限可达到1 500 mg/L左右;Cr(VI)导致菌体细胞大小分布变宽,同时使得细胞表面的—OH和—NH基团减少。当初始Cr(VI)浓度为100 mg/L时,48 h内菌株S2-3对Cr(VI)去除效率可达到85.9%,对总铬去除率为24.1%。在高Cr(VI)浓度(1 000 mg/L)下,菌株对Cr(VI)和总铬仍有一定的去除效果,分别为58.7%和3.3%。菌株S2-3主要通过还原Cr(VI)的方式去除Cr(VI)。Cr(VI)的还原与菌液ORP以及细胞表面的—OH和—NH有关;总铬的去除不是因为形成了氢氧化铬沉淀,而是Cr(III)被吸附在了细胞表面的—CO上。     

间歇好氧硫酸盐废水处理系统微生物区系解析

应用PCR-DGGE(polymerase chain reaction-denaturing gradient gel electrophoresis)技术和16S rDNA序列测定对间歇好氧硫酸盐废水处理工艺的微生物群落结构进行了研究.采集味精厂好氧池原始污泥以及实验室内间歇好氧工艺驯化后不同条件下的活性污泥样品,通过基因组DNA的提取、PCR扩增和DGGE分离,初步分析了各污泥样品的微生物群落多样性,结果表明,PCR-DGGE方法可以在一定程度上反映工艺以及操作条件对微生物群落结构的影响.通过DGGE反复分离纯化及割胶回收,DGGE检验为单一条带后进行测序并提交到GenBank数据库比对,结果表明,间歇好氧硫酸盐系统中优势菌株大多数为未培养细菌,来源于不同的污染环境,具有重要污染物降解的生态功能,其中包括与硫酸盐还原菌(Desulfobulbus propionicus)在系统发育上非常接近的菌株.     

蜡状芽孢杆菌WXZ-8的异养硝化/好氧反硝化性能研究

通过聚合酶链式反应(PCR)扩增、16S rDNA测序并结合同源性分析,鉴别出菌株WXZ-8为蜡状芽孢杆菌(Bacillus ce-reus).对菌株WXZ-8进行异养硝化/好氧反硝化性能测定,并通过正交实验进行培养条件的优选,选取的因素为COD/N、温度、转速和pH.结果表明,对菌株WXZ-8影响最大的因素是转速,其次为COD/N;在最优条件(即温度=30℃、COD/N=25、pH=9.0、转速=180 r/min)下,菌株WXZ-8的氨氮去除率最高达到96.06%.在最优条件下,提高初始氨氮质量浓度为211.52、429.16、897.29mg/L时.菌株WXZ-8在前48 h的氨氮去除速度均达到最大,分别为119.04、94.76,142.21 mg/(L·d),其氨氮去除率最高分别为94.41%、73.43%、51.08%.菌株WXZ-8具有良好的异养硝化/好氧反硝化性能.     

A2O工艺中雌激素的行为变化和去除机理

研究了厌氧-缺氧-好氧(A2O)活性污泥工艺对生活污水中天然雌激素雌酮(Estrone,E1)、17β-雌二醇(17β-Estradiol,E2)以及17α-乙炔基雌二醇(17α-Ethynylestradiol,EE2)的去除性能。在对COD、N和P具有良好去除效果的前提下,对E1、E2和EE2的去除率可分别达到92.7%、100%和62.7%。通过对各反应单元内3种雌激素的物料平衡分析,表明A2O工艺对雌激素的去除主要发生在厌氧段和好氧段。以失活污泥作为对照组,好氧硝化过程中雌激素去除的小试实验发现,好氧过程中E1、E2的去除主要依靠生物降解作用,而EE2的去除则主要依赖于活性污泥对其的吸附作用。     

好氧反硝化菌BN5脱氮降苯特性

以好氧反硝化菌Pseudomonas sp.BN5开展去除硝态氮实验,同时研究其降解苯的特性。结果表明,在最佳转速180 r·min-1条件下,菌株在72 h内可完全降解80 mg·L-1苯;同时,硝态氮的去除率为93.2%。氮平衡分析表明:57.1%的硝态氮转化为胞内氮,32.7%以含氮气体形式被去除;细胞主要通过好氧反硝化和细胞同化作用脱氮。高浓度的苯对细胞生长和硝态氮的去除均有抑制作用,可通过固定化细胞提高降解性能。固定化菌在批式反应器中能高效降苯脱氮,且能够保证反应器的稳定。菌株Pseudomonas sp.BN5可以有效的去除苯和硝酸盐,为该菌的实际应用奠定了基础。     

超强静磁场对染料脱色菌Escheriehia coli的acpD基因的影响

将大肠杆菌E.coli ATCC8739置于12.0 T超强静磁场(ultra-strong static magnetic field,SMF)中进行处理,获得了磁场处理0.5、1、2、4和8 h的菌株E.coli-SMFn(n=0.5、1、2、4、8)。在37℃、pH 7、静置的条件下,菌株对偶氮染料AR14(I.C.Acid Red 14)的脱色结果指出,当反应进行到4、6和8 h时,E.coli-SMF8的脱色效率分别为18%、55%和96%,远高于E.coli ATCC8739的3%、19%和50%,表明SMF作用显著地增强了菌株的脱色效率。基因组DNA提取、PCR扩增、分子克隆以及基因测序的实验结果进一步表明,全部6例E.coli ATCC8739菌株的偶氮还原酶基因(acpD)序列均与GenBank中报道的完全一致;而E.coli-SMF8菌株的acpD-SMF8核酸序列中缺失了第99位的胞嘧啶。该缺失突变不仅使acpD-SMF8的核酸序列与acpD的存在显著不同,同时得到了具新活性中心的偶氮还原酶AzoR-SMF8。这个新的活性中心具有更强的黄素(FMN)结合能力,因此使该酶与偶氮染料的亲和力大大增加,促进了脱色效率的提高。     

Pseudomonas sp. BS-1发酵产物对土壤中钍的淋洗作用

从焦化废水污泥中筛选出一株产生物表面活性剂的菌株,将其命名为BS-1,16SrDNA系统发育学分析确定其属于假单胞菌属(Pesudomonas sp.)。该菌株发酵产物初步鉴定为鼠李糖脂,在其临界胶束浓度为0.56g·L~(-1)时,可将水溶液的表面张力从76.8mN·m~(-1)降至38.5mN·m~(-1)。将菌株发酵产物溶液作为淋洗剂,采用浸提和土柱淋洗的方法研究了BS-1发酵产物对污染土壤中钍的去除效果,结果表明:当pH为10,浓度为3 g·L~(-1),振荡时间为72h时,钍的去除率可达70.14%;在柱状动态实验中,当淋洗量达到800mL时,发酵产物溶液对钍的累积去除量最大为65.03 mg·kg~(-1),发酵产物溶液对钍的累积去除量明显优于去离子水。对比淋洗后土壤中钍的形态占比可知,残渣态增加10.16%,氧化结合态减少了11.41%。对比淋洗前后土壤中钍的形态含量可知,酸可提取态、氧化结合态、有机结合态分别减少了83.25%、75.22%、60.70%。淋洗后钍的稳定性增强。     

表面活性剂强化植物-微生物联合修复双对氯苯基三氯乙烷污染土壤研究

通过实验对比研究植物(油菜)修复、微生物(甲基营养型芽孢杆菌(Bacillus methylotrophicus))修复、表面活性剂(聚氧乙烯山梨醇酐单硬脂酸酯(Tween 60))以及联合修复技术对双对氯苯基三氯乙烷(DDT)污染土壤的DDT去除效果。结果表明:以植物-表面活性剂-微生物共同作用下的DDT去除效果最好,土壤DDT去除率达到52.44%;油菜不仅可有效去除土壤中残留的DDT,同时只在地下部分对DDT进行了微量吸收,但没有进行转运,防止了农药在油菜可食部位的累积,保障了食品与生产安全。     

二氧化钛滤柱对高砷污酸废水的吸附去除

冶炼废水中高浓度砷的去除及回收是环境领域面临的一大挑战。提出利用颗粒TiO_2填充滤柱对酸性废水中的高浓度砷进行连续在线吸附去除。经过3个连续串联的TiO_2滤柱,原水中高达2.5 g·L-1的三价砷可降至国家工业废水排放标准以下(0.5 mg·L~(-1))。空床接触时间(EBCT)实验结果表明,当EBCT=20 min时滤柱中TiO_2可达到最大利用率。使用后的TiO_2颗粒可用H2SO4和Na OH进行反洗再生。X射线衍射分析结果表明,经过再生后颗粒TiO_2的晶型并未发生变化,能够实现对砷的再吸附。基于同步辐射技术的微束X射线荧光(μ-XRF)分析结果表明,反洗后少量固体残渣中有多种重金属共存。砷的K边微束X射线近边吸收结构(μ-XANES)表明固体残渣中存在五价砷,说明反洗过程中三价砷部分氧化。固体残渣可以通过化学提纯的方式实现砷及多种共存重金属的回收。再生废液可与原酸性废水混合调p H至中性后重新进入滤柱进行吸附去除。提出的利用颗粒TiO_2处理酸性冶炼废水的新方法可有效去除废水中的高浓度三价砷,吸附剂可重复利用,同时可以实现砷及其他重金属的回收,整个工艺流程几乎不产生废渣,对环境友好的同时可产生经济效益。     

物化-生化组合工艺处理提铜选矿药剂生产废水中试实验研究

采用“预处理(酸化沉降+铁炭微电解+石灰中和)-生化(水解酸化+两级好氧生化)-深度处理(Fenton试剂催化氧化+石灰中和)”组合工艺对提铜选矿药剂生产废水进行现场中试实验研究,主要考察其COD去除、脱色、除味效果,重点考察生化单元运行特性及其对有机物的去除能力.实验结果表明,该组合工艺对该生产废水具有较好的净化效果,出水清澈透明、无气味,主要出水水质指标pH、色度、COD可以达到《污水综合排放标准(GB8976-1996)》二级标准.     

纤维素降解细菌筛选及降解特性分析

基于获得高效纤维素降解细菌的目的,通过LB培养基的培养以及刚果红培养基的筛选,从牛粪堆肥中筛选获得2株高效纤维素降解细菌。经鉴定,分别为枯草芽胞杆菌(Bacillus subtilis)和地衣芽胞杆菌(Bacillus licheniformis)。所筛选得到的菌种具有很高的滤纸降解能力,可在6d内使滤纸剧烈崩溃,振摇成均匀糊状;其中,地衣芽胞杆菌的羧甲基纤维素钠酶活峰值在发酵第4天达到峰值(237U/g)。     

Bioluminescent yeast assays for detecting estrogenic and androgenic activity in different matrices

In this paper we describe the construction and use of a set of bioluminescent yeast strains for the detection of compounds that can affect androgen or estrogen receptor mediated hormonal signalling. The set includes Saccharomyces cerevisiae strains expressing human androgen receptor (AR), estrogen receptor alpha (ERalpha) or estrogen receptor beta (ERbeta), along with firefly luciferase controlled by a respective hormone responsive promoter. A constitutively luminescent strain was included in the set for determining the cytotoxicity of the sample. Yeast cells were incubated with pure chemicals or complex samples for 2.5 h, after which the signal could be detected from the cell-sample mixture after simply adding the D-luciferin substrate. The assays could be completed in one day and they required no cell lysis or centrifugation steps, which makes them suitable for high-throughput analysis of samples. Due to a short incubation time the assays are directly applicable to different sample matrices, requiring no pretreatment of the samples. The assays were used to assess the hormonal activity in moisturizing lotions as an example of a complex sample matrix known to contain endocrine disrupting chemicals. Six out of eight tested moisturisers showed high estrogenic activity, whereas no androgenic activity was observed in the samples.     

可用于水体污染控制的氨氮转化菌筛选及部分降解特性的实验研究

从南京禄口水产养殖基地淡水鱼塘取淤泥作为分离菌株的土源,采用选择性富集培养法,从中分离到能以硫酸铵为氮源的菌株7株,对7个菌株进行氨氮降解实验,它们氨氮转化率分别为14.8%、19.7%、53.4%、94.2%、29.1%、63.5%和41.7%,其中AN-4菌株的转化率最高且生长良好。通过AN-4菌株16S rRNA基因序列分析以及生理生化方法,鉴定此菌株为克雷伯氏菌属(Klebsiellasp.)。对菌株AN-4转化氨氮的特性及温度、pH值、氨氮初始浓度和菌株接种量对其氨氮转化率的影响研究,结果表明,菌株AN-4降解氨氮的最适条件为:温度为30℃和pH值为8.0;当氨氮初始浓度为30mg/L时,AN-4菌株在24 h内的氨氮降解率可达85%以上,且能耐受高达200 mg/L的氨氮浓度;AN-4活化菌液浓度为108cfu/mL,当接种量为3×106cfu/mL时,AN-4菌株在24 h内的氨氮降解率为87.75%。综合上述结果,符合淡水养殖水环境条件,说明AN-4菌株适合在水产养殖中应用,为将菌株AN-4应用于水产养殖环境修复提供了理论依据。     

Ca-Mg kutnahorite and struvite production by Idiomarina strains at modern seawater salinities

The production of Mg-rich carbonates by Idiomarina bacteria at modern seawater salinities has been investigated. With this objective, four strains: Idiomarina abyssalis (strain ATCC BAA-312), Idiomarina baltica (strain DSM 15154), Idiomarina loihiensis (strains DSM 15497 and MAH1) were used. The strain I. loihiensis MAH1 is a new isolate, identified in the scope of this work. The four moderately halophilic strains precipitated struvite (NH4MgPO4 x 6H2O) crystals that appear encased by small Ca-Mg kutnahorite [CaMg(CO3)2] spheres and dumbbells, which are also regularly distributed in the bacterial colonies. The proportion of Ca-Mg kutnahorite produced by the bacteria assayed ranged from 50% to 20%, and I. abyssalis also produced monohydrocalcite. All precipitated minerals appeared to be related to the bacterial metabolism and, consequently, can be considered biologically induced. Amino acid metabolism resulted in a release of ammonia and CO2 that increase the pH and CO(3)(2-) concentration of the culture medium, creating an alkaline environment that favoured carbonate and struvite precipitation. This precipitation may be also related to heterogeneous nucleation on negatively charged points of biological structures. Because the nature of the organic matrix determines which ion is preferentially adsorbed and, consequently, which mineral phase is formed, the uniquely high content in odd-iso-branched fatty acids of the Idiomarina suggests that their particular membrane characteristics could induce Ca-Mg kutnahorite production. The Ca-Mg kutnahorite, a mineral with a dolomite-ordered structure, production at seawater salinities is noticeable. To date, such precipitation in laboratory cultures, has only been described in hypersaline conditions. It has also been the first time that biomineralization processes have been related to Idiomarina bacteria.     

Diversity of biphenyl degraders in a chlorobenzene polluted aquifer

Biphenyl degrading bacteria (40 strains) have been isolated along a gradient of chlorobenzene pollution from an aquifer which did not contain any PCB to answer the question of how metabolic/catabolic abilities exist in ecosystems that have not been stressed with the relevant substrates is important for intrinsic bioremediations. Only few of the isolates were characterized by 16S rRNA gene sequence analyses as Pseudomonas species while the majority were Gram-positive, belonging to the order Actinomycetales and representing the genera Rhodococcus and Arthrobacter. The strains could grow on a variety of chlorobenzoates but no pattern of substrate usage and phylogeny or pollution gradient could be found. Strains which were able to grow on 2,5-dichlorobenzoate were often also able to use 3,4- and 3,5-dichloro- and 2,3,5-trichlorobenzoate or those using 2-chlorobenzoate could usually use 2,6-dichlorobenzoate as well. From that results, it is concluded that a highly diverse, basic metabolic activity for PCB degradation existed at this site despite the absence of PCB.     

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.     

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-N?-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.     

Enhanced degradation of fluorene in soil slurry by Absidia cylindrospora and maltosyl-cyclodextrin

This study investigates the fungal biodegradation of fluorene, a polycyclic aromatic hydrocarbon, in liquid medium and soil slurry. Fungal strains and cyclodextrins were used in order to degrade fluorene and optimize fluorene bioavailability and degradation in soil slurries. After a procedure of selection in solid and liquid media, maltosyl-cyclodextrin, a branched cyclodextrin was chosen. 47 fungal strains isolated from a contaminated site were tested for biodegradation. Results showed the greater efficiency of "adapted" fungi isolated from contaminated soil vs reference strains belonging to the collection of the laboratory. These assays allowed us to select the most efficient strain, Absidia cylindrospora, which was used in a bioaugmentation process. Bioaugmentation tests were performed in an artificially contaminated non-sterile soil. In the presence of A. cylindrospora, more than 90% of the fluorene was degraded within 288 h, while 576 h were necessary in the absence of fungal bioremediation. It also appeared that biodegradation was enhanced by amendment with previously selected maltosyl-cyclodextrin. The results of this study indicate that A. cylindrospora and maltosyl-cyclodextrin could be used successfully in fluorene bioremediation systems.     

产表面活性剂菌筛选及其对柴油降解影响研究

运用微生物培养方法,从饭店排污口污泥中筛选了7株产表面活性剂菌株。为了研究产表面活性剂菌在柴油降解过程中所产生的影响,分别将这些菌株与柴油降解菌(实验室提取的另一株假单胞菌)共同作用,其中一株(B_(26))不但可以将降解诱导期从6 d缩短至4 d,而且能将降解率由原来的71.1%提高至80.6%,具有较大的研究价值。实验着重对B_(26)的作用机理、柴油降解的影响因素等进行了分析研究。经形态学和生理生化实验鉴定,B_(26)属于芽孢菌属,其代谢过程中产生脂肽类表面活性剂,利用冷冻干燥法提取生物表面活性剂产量为1.57 g/L。     

石油降解菌的筛选及其降解能力的研究

从广州石化污水处理厂废水中自行分离出 30株除油菌 ,用市售的 90 # 柴油作为油品进行筛选 ,所得菌种用于处理石化厂物理隔油后的废水。通过研究含油量和接种量对除油率、COD的去除率和pH值的影响以及酸、碱、盐对除油率和COD去除率的影响来比较这些菌种对石化废水的处理效果。结果表明 ,6 # 菌株除油和去除有机物的效果都比较好 ,除油率约在 70 %左右 ,最高为 83.6 7% ,COD去除率约为 5 5 %左右 ,最高为 6 0 .0 1% ;5 # 菌株对环境要求较高 ,在碱性环境下表现出较好的除油和去除有机物的能力 ,除油率和COD去除率分别为 5 5 %和 5 0 %左右。实验菌株在消除石化废水的异味方面也有一定的效果。