高效芘降解菌N12的分离鉴定与降解特性

以芘为目标降解物,利用选择性富集培养方法,从沈抚灌区污染土壤中分离到一株高效芘降解菌N12,经生理生化试验和16S rDNA测序分析,该菌被鉴定为分枝杆菌属（Mycobacterium sp.）.菌株N12能以菲、苊、芴和芘为唯一碳源和能源生长,不能以蒽、萘和苯并芘为唯一碳源和能源生长.在菲和芘共同存在的情况下菌株N12可降解苯并芘,9 d内对苯并芘降解率可达79.0%.摇瓶降解试验表明,菌株N12可在7 d内将100 mg·L^-1的芘降解94.4%,14 d内将其完全降解;可将600 mg·L^-1的芘在7 d内降解56.1%,14 d内降解95.5%.添加葡萄糖可促进N12对芘的降解.菌株N12是一株优良的多环芳烃降解菌,可作为多环芳烃污染土壤生物修复的菌种资源.     

一株高效菲降解菌的筛选及降解条件研究

从南京某石化厂排污口附近采集土样,以菲为碳源的选择性培养基分离筛选到一株菲高效降解菌F10a,根据形态和生理生化特性初步鉴定为芽孢杆菌属,并对其降解菲的特性及各种影响因素进行了研究.结果表明,F10a在50 mg·L^-1的条件下,28 ℃振荡培养27 h,菲的降解率达到98.12%;静置培养8 h,菲的降解率达到98.7%.pH值分别为、6、8时,F10a对菲具有良好的降解效能;pH值为10时F10a不生长.Zn²⁺与Pb²⁺的存在不影响F10a的降解效能,Cu²⁺可以延缓菲的降解,Cr²⁺对F10a有毒性.F10a在菲浓度为200 mg·L^-1时,28 ℃振荡培养8 h,降解率为99.6%.菲的降解程度与细菌数量的增长呈正相关关系.     

嗜麦芽寡养单胞菌PX1的降解芘特性及定殖效能

为丰富多环芳烃降解菌菌种库、降低农作物的污染风险,本研究对一株可高效降解多环芳烃(PAHs)的植物内生菌进行筛选鉴定,并初步探究其降解途径以及定殖效能。结果表明: 菌株PX1为嗜麦芽寡养单胞菌。该菌株对多环芳烃的降解具有广谱性,7 d几乎可彻底降解PAH无机盐培养基中的萘,在分别含有50.0 mg·L^-1菲、20.0 mg·L^-1芘、20.0 mg·L^-1荧蒽和10.0 mg·L^-1苯并[a]芘的培养体系中,对菲、芘、荧蒽、苯并[a]芘的降解率分别为72.6%、50.7%、31.9%和12.9%。选取芘作为PAHs模型研究菌株PX1的降解特性。酶活性试验表明,芘可诱导菌株PX1体内邻苯二甲酸双加氧酶、邻苯二酚-1,2-双加氧酶和邻苯二酚-2,3-双加氧酶的活性。在芘降解过程中检测到4,5-环氧化芘、4,5-二羟基芘、龙胆酸/原茶儿酸、水杨酸、顺-己二烯二酸/2-羟粘糠酸半醛、顺-2′-羧基苯丙酮酸、1-羟基-2-萘甲酸、水杨醛等中间产物。浸种定殖试验表明,菌株PX1可高效定殖到空心菜和小麦体内,显著促进空心菜和小麦生长,并能够将空心菜、小麦体内及其生长基质中的芘浓度分别降低29.8%～50.7%、52.4%～67.1%和8.0%～15.3%。表明菌株PX1主要通过“水杨酸途径”和“邻苯二甲酸途径”降解芘,且可以定殖到植物体内,促进植物生长。     

新异养硝化菌Colloidessp. JZ1-1的鉴定及其硝化性能

从驯化后的活性污泥中筛分、诱变出一株性能较好的异养硝化菌JZ1-1.经形态及生理生化特性分析,鉴定菌株JZ1-1为胶样菌属(Colloides sp.).分别考察了碳源、C/N、pH、溶解氧、温度和铵态氮初始浓度对JZ1-1硝化性能的影响.结果表明: 菌株对柠檬酸钠的利用较好;C/N为10～14、30 ℃、pH 6-9和转速150 r·min^-1以上有利于铵态氮的降解;菌株对中高浓度铵态氮废水（100 mg·L^-1≤铵态氮浓度≤500 mg·L^-1）的降解效果显著.经5次继代培养,菌株的稳定性较好.     

3株多环芳烃高效降解菌株的分离鉴定及降解特性

筛选分离降解多环芳烃(PAHs)的优势菌种对开展多环芳烃污染生态系统修复具有重要的现实意义。本研究以焦化厂周围受多环芳烃污染的土壤为菌源,经过富集培养驯化和平板分离,获得11株能降解多环芳烃的菌株。通过形态观察、生理生化特征及16S rRNA序列比对对菌株进行鉴定,筛选出3株PAHs高效降解菌,分别命名为DJ-3、DJ-8、DJ-10。经16S rRNA序列分析鉴定,DJ-3为假单胞菌属、DJ-8为克雷伯氏菌属、DJ-10为芽孢杆菌属。对菌株降解能力的研究表明,3株菌(DJ-3、DJ-8、DJ-10)培养7 d后对混合多环芳烃中菲(200 mg·L^-1)、芘(200 mg·L^-1)和萘(160 mg·L^-1)的降解率分别为48.9%～65.9%、38.9%～43.1%和57.6%～64.9%。3株菌对多环芳烃混合样品(1200 mg·L^-1)的降解率分别为49.1%、44.5%、53.9%,远高于其他8株筛选菌,为PAHs高效降解菌株。3种菌株两两之间和三者组合均无拮抗关系。研究结果将为构建高效的多环芳烃降解菌群、提高多环芳烃原位污染土壤的生物修复效果奠定基础。     

对-氯代苯胺(PCA)在填充床生物反应器中的降解作用

以氯代苯胺(PCA)为选择基质,用驯化技术从降解对二氯苯(p-DCB)的富集培养物中得到了以同化PCA为唯一碳源和氮源的混合微生物。将这种固定在填充床反应器中的微生物用于PCA的降解作用研究中。在该反应器里,PCA的生物降解遵循Logistic方程q=q_max/(1+e^α-βU_v).由方程求出了主要的动力学常数,K_s(半速率常数)和q_max(最大比基质降解速率).于PCA降解的同时,释放氯离子到培养基中。在水力停留时间3h, 进水PCA浓度为360mg·L^-1情况下,基质的体积降解率达到125mg·L^-1·h^-1;基质的百分去除率为91%.     

多环芳烃降解菌筛选及其降解特性

通过选择性富集培养,从辽河油田稠油污染土壤4号土样中,获得了能以高浓度菲(2000mg·L^-1)为唯一碳源和能源快速生长的优势菌系和优良菌株ZL5．16S rDNA核苷酸序列分析表明,ZL5菌株归类于鞘氨醇单胞菌属,分得的菌系和菌株有较强的降解菲能力,120h混合菌系降解了投加菲的95．28％,菌株降解了69．24％,但它们对芘的降解能力均较低,外加碳源葡萄糖可提高菌系和菌株的菲、芘降解能力,加量多。提高幅度大,但超过一定量。降解速率开始下降,表现出抑制效应。所以,应用时需控制适宜的浓度。     

芘高效降解菌的分离鉴定及其降解特性的研究

以芘为惟一碳源.采用寓集培养方法,从沈抚灌区石油污染土壤中分离得到一株芘降解菌B05.根据形态学观察、生理牛化鉴定和16S rDNA序列分析结果.将菌株B05鉴定为Aminobacter ciceronei.在芘初始浓度为1mg/L的液体无机盐培养基中,培养10d,菌株B05对芘的降解率为51%;在芘初始浓度为1mg/kg的土壤培养基条件下,培养30d,菌株B05对芘的降解率可达51%;在芘初始浓度为50mg/L的乙醇液体培养基条件下,培养5d,菌株B05对芘的降解率可达25.9%.对菌株培养条件进行优化,经SlideWrite统计软件拟合,菌株B05在牛肉膏蛋白胨液体培养基上的最适生长pH值为7.3,最适生长温度为32.5℃,最适装液量为25.4mL(150mL三角瓶).     

光催化降解敌百虫农药废水的影响因素分析

在TiO₂悬浮体系,对农用敌百虫有机磷农药进行光催化氧化降解反应。发现光催化降解过程中适当补充NaOH溶液,可以维持较高的有机磷降解率,对于处理有机磷农药废水保持一定的pH值有作用。敌百虫农药有机磷含量起始浓度处于3.1mg·L^-1和31mg·L^-1之间,在50mg的催化剂TiO₂作用下90min内无机磷浓度变化符合零级反应,而且反应速率常数和敌百虫起始浓度呈线形关系,实验中探讨了降解过程中出现的影响因素。     

芍药愈伤组织中体细胞胚发育过程的组织细胞学观察

以芍药（Paeonia lactiflora Pall.）3个芍药品种的茎段、叶片、叶柄为外植体,诱导体细胞胚发生,并采用石蜡切片法对该发育过程进行组织细胞学观察。结果表明：‘Going Bananas’的茎段愈伤诱导率达100%,增殖率在4.0以上,表现最佳;非胚性愈伤组织最佳诱导、增殖培养基为WPM+IAA 1.0mg·L^-1+6-BA 1.0mg·L^-1+NAA 0.5mg·L^-1+TDZ 0.5mg·L^-1+CH 0.625g·L^-1;愈伤组织转入到1/2 MS（Ca²⁺加倍）+2,4-D 2.0mg·L^-1+ABA 0.5mg·L^-1或ZT 1.0mg·L^-1的培养基中,连续暗培养90后得到胚性愈伤;之后转入到成熟培养基1/2MS（Ca²⁺加倍）+6-BA 1.0mg·L^-1+NAA 0.2mg·L^-1中,见光培养60d,逐渐发育至球形胚和心形胚。在石蜡切片观察中,芍药的体细胞胚起源方式包括外起源和内起源两个途径。在外起源方式中包括单个表层细胞的外起源和多个表层下细胞的共同起源。3种方式的区别主要在于起始的位置和起始细胞数量,后期均形成原胚结构。胚性细胞的分裂方式为对称分裂,未发现不对称分裂细胞的存在。     

Optimization of Callus Induction Conditions from Immature Embryos of Maize under Stress

The embryos of maize (Zea mays L.) inbred lines GS02, GS07, GS08, GS11 and GS15 were used as receptor materials to optimize the receptor system from the aspects of genotype, medium components and stress (PEG6000, mannitol, salt and low phosphorus). The results showed that GS07 had the highest induction rate (95.2%). Orthogonal test analysis showed that the best combination of medium components in induction was A₂B₃C₁D₃₍₂₎, namely, the concentration of 2, 4-dichlorophenoxy acetic acid (2,4-D) was 4 mg·mL^-1, the concentration of L-Proline (L-Pro) was 0.8 mg·mL^-1, and the concentration of silver nitrate (AgNO₃) was 10 mg·mL^-1 (or 5 mg·mL). Interestingly, we found that the optimal medium supplemented with 30 g·L^-1 PEG6000 or 80 g·L^-1 mannitol was suitable for antioxidant enzyme activity and malondialdehyde (MDA) content in GS07 callus. Exogenous 10 mmol·L^-1 Ca²⁺ in the medium components with 100 mmol·L^-1 sodium chloride (NaCl) could improve the activity of antioxidant enzymes in GS07 callus. Callus of GS07 could divide normally and grow well in medium components with 27 mg·L^-1 KH₂PO₄. This study enhanced the adaptability of maize callus to stress and optimized the culture conditions.

     

Rapid Propagation of <i>Rhynchostylis retusa in Vitro</i>

An efficient regeneration system of Rhynchostylis retusa was established to provide technical reference for the application of tissue culture tube seedlings in production. The mixtures of callus and protocorm from aseptic germination were used as explants. The optimal media of each stage was selected for callus proliferation, protocorm occurrence and growth, rejuvenation and rooting via a single, complete combination and orthogonal experiment. The results showed that the optimal medium for callus proliferation, protocorms occurrence and growth was 1/2 Murashige and Skoog (MS) medium adding 50 g·L⁻¹ banana puree, 0.1 mg·L⁻¹ α-naphthaleneacetic acid (NAA), 1.5 mg·L⁻¹ 6-benzylaminopurine (6-BA) and 1.0 mg·L⁻¹ kinetin (KT) with 17.33 proliferation coefficient of callus and 19.63 occurrence coefficient of buds after 90 days. Then the buds occurred from protocorm were cultured on 1/2 MS medium including 100 g·L⁻¹ banana puree, 1.0 mg·L⁻¹ NAA, 2.0 mg·L⁻¹ 6-BA and 0.05 mg·L⁻¹ KT, in which the proliferation coefficient of callus was 10.32 and occurrence coefficient of buds reached 17.87. In the further subculture, the same medium was simultaneously used for callus proliferation, protocorm occurrence and bud growth. The plantlets developed roots in 1/2 MS medium containing 70 mL·L⁻¹ coconut water and 1.5 mg·L⁻¹ NAA with 100% rooting rates after 90 days. The survival rate was more than 90% after domestication and transplantation. This regeneration protocol will provide technique foundation for protecting wild resource and developing artificial cultivation.     

Isolation and characterisation of phenol-degrading <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> MTCC 4996

A novel indigenous Pseudomonas aeruginosa strain (MTCC 4996) isolated from a pulp industrial effluent-contaminated site was capable of degrading phenol up to a concentration of 1,300 mg L⁻¹ within 156 h. Complete degradation was observed at pH values ranging from 6.0 to 10.0 and temperatures from 15 to 45°C, with an optimum pH of 7.0 and optimum temperature of 37°C. At an optimum shaking speed of 100–125 rpm, 100% degradation was observed in 66 h, as compared to 84 h under static conditions. Glucose and peptone at lower concentrations enhanced phenol degradation. The rate of phenol degradation was most sensitive to added Hg. Low concentrations of Fe, Cu, Pb, Zn, and Mn stimulated and enhanced the rate of degradation.     

Biodegradation of nicotine by newly isolated Pseudomonas sp. CS3 and its metabolites

Aims: Isolation and characterization of nicotine‐degrading bacteria with advantages suitable for the treatment of nicotine‐contaminated water and soil and detection of their metabolites. Methods and Results: A novel nicotine‐degrading bacterial strain was isolated from tobacco field soil. Based on morphological and physiochemical properties and sequence of 16S rDNA, the isolate was identified as Pseudomonas sp., designated as CS3. The optimal culture conditions of strain CS3 for nicotine degradation were 30°C and pH 7·0. However, the strain showed broad pH adaptability with high nicotine‐degrading activity between pH 6·0 and 10·0. Strain CS3 could decompose nicotine nearly completely within 24 h in liquid culture (1000 mg L^?1 nicotine) or within 72 h in soil (1000–2500 mg kg^?1 nicotine) and could endure up to 4000 mg L^?1 nicotine in liquid media and 5000 mg kg^?1 nicotine in soil. Degradation tests in flask revealed that the strain had excellent stability and high degradation activity during the repetitive degradation processes. Additionally, three intermediates, 3‐(3,4‐dihydro‐2H‐pyrrol‐5‐yl) pyridine, 1‐methyl‐5‐(3‐pyridyl) pyrrolidine‐2‐ol and cotinine, were identified by GC/MS and NMR analyses. Conclusions: The isolate CS3 showed outstanding nicotine‐degrading characteristics such as high degradation efficiency, strong substrate endurance, broad pH adaptability, and stability and persistence in repetitive degradation processes and may serve as an excellent candidate for applications in the bioaugmentation process to treat nicotine‐contaminated water and soil. Also, detection of nicotine metabolites suggests that strain CS3 might decompose nicotine via a unique nicotine‐degradation pathway. Significance and Impact of the Study: The advantage of applying the isolated strain lies in broad pH adaptability and stability and persistence in repetitive use, the properties previously less focused in other nicotine‐degrading micro‐organisms. The strain might decompose nicotine via a nicotine‐degradation pathway different from those of other nicotine‐utilizing Pseudomonas bacteria reported earlier, another highlight in this study.     

盐碱土壤PAHs 降解菌的筛选鉴定及其降解特性

采用富集培养的方法,从天津大港油田PAHs污染盐碱化土壤中分离出一株能以菲、芘为唯一碳源和能源的优势菌TJB5。经形态观察和16S rDNA序列分析结果表明,该菌株为成团泛菌(Pantoea agglomerans)。采用液体培养的方法,研究了pH、盐度、菲芘的初始浓度对TJB5菌株降解菲芘效果的影响,确定了最佳降解条件。结果表明,该菌对菲、芘的降解具有较广泛的pH、盐度范围和良好的降解效果。在菲、芘浓度分别为50 mg/L、pH 6.8-9.5、盐度2%-3%、温度30°C条件下,接种15 d后菲降解率在93.3%以上,芘降解率在20%以上。     

Effect of Exposure Time,Contamination Level,and Type of PAH Compound on Biodegradation Capacity of Mangrove Sediment

Mangrove sediment had high natural attenuation potential with more than 50% of total PAHs being removed within 15 days. The efficiency in degrading PAHs varied with the declining order of phenanthrene (Phe), fluoranthene (Fla), and pyrene (Pyr). The Most Probable Number (MPN) of PAH-degrading bacteria in the PAH-contaminated slurries was 2 to 4 orders of magnitude higher than that in the non-contaminated mangrove slurries. The biodegradation ability of the indigenous microbial community in mangrove sediment slurry was significantly increased after exposure to polycyclic aromatic hydrocarbons. Such enhancement effect was dependent on the level and time of exposure, as well as the types of PAH compounds. The lowest contamination level of 3 mg kg^?1 was effective in promoting the degradation of Phe and Fla after seven days, but the enhancement effect for Pyr degradation was only found in the slurries exposed to contamination levels of 9 mg kg^?1 for 30 days, suggesting a threshold concentration of PAHs to stimulate growth and activity of pyrene-degrading bacteria. The contamination level higher than the threshold concentration did not lead to more degradation. The present study provides insights into the natural attenuation of PAH-contaminated mangrove sediments.     

1株四环素降解菌的分离鉴定及降解特性研究

应用微生物降解四环素具有经济有效和环境友好特点,已成为当前研究的热点。采用选择性培养基,从鸡粪中分离出1株能以四环素作为唯一碳源生长的菌株TC-1,培养7 d降解率为56.2%,初步鉴定为蜡状芽胞杆菌(Bacillus cereus)。从碳氮源组合、培养基初始pH、Na Cl浓度和装液量四方面研究了TC-1降解四环素的特性。结果表明,TC-1在以葡萄糖和酵母粉为碳、氮源生长时效果最优,培养7 d时OD600达2.17;但最优降解率出现在蔗糖和大豆蛋白胨的碳氮源组合中,为46.8%。当培养基初始pH为7时,菌株TC-1生长最好,OD600为0.44,四环素降解率为92.3%。当培养基中Na Cl浓度达15 g/L时,TC-1生长受到抑制,降解率仅为28.6%;培养基装液量为40%时降解率最高,为56.2%。     

牛角瓜离体快繁技术

该文选用牛角瓜茎段为外植体,通过组织培养方法探索牛角瓜组织培养和种苗快繁技术。结果表明:最佳外植体表面消毒方法是以0.1%HgCl_2处理7 min,外植体存活率为32.3%;初代培养基为MS+蔗糖30 g·L~(-1)+琼脂3.5 g·L~(-1),培养20 d后形成3～4 cm高的再生芽。增殖培养前期筛选的较为适宜的增殖培养基为MS+6-BA 1.5 mg·L~(-1)+NAA 0.05 mg·L~(-1)+蔗糖30 g·L~(-1)+琼脂3.5 g·L~(-1),增殖系数4.6。但在后续的培养过程中发现,牛角瓜组培苗易玻璃化,且随着世代更迭,玻璃化程度加重,到了第四代几乎全部玻璃化。因此在上述增殖培养的基础上,以AgNO_3作为玻璃化抑制剂,筛选出最终的增殖培养基为MS+6-BA1.5 mg·L~(-1)+NAA 0.05 mg·L~(-1)+AgNO_31.0 g·L~(-1)+蔗糖30 g·L~(-1)+琼脂3.5 g·L~(-1)。用此增殖培养基,培养25 d,苗高5～8 cm,增殖系数5.8,玻璃化率低于10%,且连续培养多代,玻璃化率维持在10%以下。生根壮苗培养基为1/2MS+NAA 1.0 mg·L~(-1)+蔗糖20 g·L~(-1)+琼脂3.6 g·L~(-1),培养14 d,生根率98%;将生根苗移栽于70%遮阴度的大棚中,30 d后,苗高20 cm左右,成活率85%。利用该方法可对牛角瓜优良种苗进行规模化生产。     

Characteristics of an endophytic pyrene-degrading bacterium of Enterobacter sp. 12J1 from Allium macrostemon Bunge

One pyrene-degrading endophytic bacterium was isolated from plants grown in polycyclic aromatic hydrocarbon-contaminated soils and identified as Enterobacter sp. 12J1 based on the 16S rDNA gene sequence analysis. Heavy metal and antibiotic resistance, degradation of pyrene, solubilization of inorganic phosphate and cell surface hydrophobicity characteristics of the isolate were further characterized. The isolate was also evaluated for promoting plant growth of wheat and maize and pyrene removal from pyrene-amended soil in pot experiments. High-performance liquid chromatograph (HPLC) analysis showed that the degradation rate of pyrene (5 mg l⁻¹) by the endophytic bacterial strain 12J1 was 83.8% under 28 °C for 7 days. The Enterobacter sp. 12J1 could produce indole acetic acid (IAA), siderophore and solubilize inorganic phosphate. The Enterobacter sp. 12J1 also has a cell surface hydrophobicity. In the live bacterial inoculation experiment, an increase in pyrene removal varying from 60% to 107% was observed in the planted soils treated with 100 mg kg⁻¹ of pyrene compared with the unplanted soils. The rate of pyrene removal increased by 43–65% in the live bacterium-inoculated planted soils compared with the dead bacterium-inoculated planted soils. Although there were no significant differences in the total culturable bacterial numbers between live and dead bacterial inoculation, the numbers of pyrene-degrading bacteria were significantly greater in the live bacterium-inoculated planted or unplanted soils. The isolate could colonize the tissue (root and stem) interiors and rhizosphere soils of wheat and maize after root inoculation.     

Evaluation of a creosote-based medium for the growth and preparation of a PAH-degrading bacterial community for bioaugmentation

Creosote was evaluated as an inexpensive carbon source for growing inocula of a polycyclic aromatic hydrocarbon (PAH)-degrading bacterial community (community five). Creosote was a poor growth substrate when provided as sole carbon source in a basal salts solution (BSM). Alternatively, peptone, yeast extract or glucose in BSM supported high growth rates, but community five could not subsequently degrade pyrene. A combination of creosote and yeast extract in BSM (CYEM) supported growth and maintained the pyrene-degrading capacity of community five. Optimum pyrene-degrading activity occurred when the inocula were grown in creosote and yeast extract concentrations of 2 ml L⁻¹ and 1 g L⁻¹ respectively: concentrations outside these values resulted in either low biomass yields or loss of PAH-degrading activity. CYEM-grown community five inocula degraded 250 mg L⁻¹ of pyrene in BSM at a rate comparable to cultures inoculated with community five grown in BSM-pyrene. However, the CYEM-grown community showed a 40% lower rate of PAH degradation in a synthetic PAH mixture compared with pyrene-grown cells and there was an increase in the lag period before the onset of PAH degradation. This appears to reflect a weaker induction of PAH catabolism by CYEM compared to BSM-pyrene. Journal of Industrial Microbiology & Biotechnology (2000) 24, 277–284. Received 24 August 1999/ Accepted in revised form 20 January 2000