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1.
氯苯降解菌的筛选鉴定及降解特性研究 总被引:2,自引:0,他引:2
本文采集化工厂排污口的污泥样品, 在含有氯苯为唯一碳源的基本培养基中, 先后分离筛选出7株能够降解氯苯的微生物菌株。通过对分离菌株的16S rRNA基因序列进行分析, 发现其中5株细菌分别属于放线菌目的考克氏菌属(KD139)、红球菌属(KD140和KD142)和节杆菌属(KD230和KD232), 1株细菌属于杆菌目的芽胞杆菌d属(KD178), 另外1株细菌属于黄色单孢菌目的寡食单胞菌属(KD237); 同时我们构建了系统进化树, 确定分离菌株的相对进化地位。本文还利用气相色谱方法, 对分离菌株降解氯苯的能力进行了初步分析, 其中寡食单胞菌KD237降解氯苯能力最高, 24 h内氯苯分解率达60.78%。 相似文献
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Isolation and Characterization of Bacteria Capable of Tolerating the Extreme Conditions of Clean Room Environments 总被引:2,自引:1,他引:1 下载免费PDF全文
Myron T. La Duc Anne Dekas Shariff Osman Christine Moissl David Newcombe Kasthuri Venkateswaran 《Applied microbiology》2007,73(8):2600-2611
In assessing the bacterial populations present in spacecraft assembly, spacecraft test, and launch preparation facilities, extremophilic bacteria (requiring severe conditions for growth) and extremotolerant bacteria (tolerant to extreme conditions) were isolated. Several cultivation approaches were employed to select for and identify bacteria that not only survive the nutrient-limiting conditions of clean room environments but can also withstand even more inhospitable environmental stresses. Due to their proximity to spacefaring objects, these bacteria pose a considerable risk for forward contamination of extraterrestrial sites. Samples collected from four geographically distinct National Aeronautics and Space Administration clean rooms were challenged with UV-C irradiation, 5% hydrogen peroxide, heat shock, pH extremes (pH 3.0 and 11.0), temperature extremes (4°C to 65°C), and hypersalinity (25% NaCl) prior to and/or during cultivation as a means of selecting for extremotolerant bacteria. Culture-independent approaches were employed to measure viable microbial (ATP-based) and total bacterial (quantitative PCR-based) burdens. Intracellular ATP concentrations suggested a viable microbial presence ranging from below detection limits to 106 cells/m2. However, only 0.1 to 55% of these viable cells were able to grow on defined culture medium. Isolated members of the Bacillaceae family were more physiologically diverse than those reported in previous studies, including thermophiles (Geobacillus), obligate anaerobes (Paenibacillus), and halotolerant, alkalophilic species (Oceanobacillus and Exiguobacterium). Non-spore-forming microbes (α- and β-proteobacteria and actinobacteria) exhibiting tolerance to the selected stresses were also encountered. The multiassay cultivation approach employed herein enhances the current understanding of the physiological diversity of bacteria housed in these clean rooms and leads us to ponder the origin and means of translocation of thermophiles, anaerobes, and halotolerant alkalophiles into these environments. 相似文献
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Ya-Wei Zhu Yu-Hua Zhao Xiao-Yan Lin Li Yang 《World journal of microbiology & biotechnology》2005,21(6-7):1195-1200
Summary An aerobic bacterium named strain BH was isolated from soil samples based on its bensulfuronmethyl-degrading characteristics
using continuous enrichment cultures. The cells of the strain were non-motile, gram-positive short rods. Colonies formed on
agar medium were round, smooth, sticky, white-yellow in colour and of butyrous consistency. Analyses of nutritional utilization
in Biolog microplates, conventional phenotypic characteristics and 16S rRNA gene sequencing were consistent with assigning
strain BH to the genus Brevibacterium. Growth of the cells and their ability to degrade bensulfuronmethyl were simultaneously monitored under different liquid
medium conditions during 7 days of incubation. They degraded bensulfuronmethyl from 100 to 70.6 mg l−1 in mineral M9 medium and exhibited more effective degradation in the presence of yeast extract, completely removing an initial
concentration of 100 mg l−1 and at best 80% of an initial concentration of 200 mg l−1. Further studies are required to determine the potential use of the isolate in the disposal of bensulfuronmethyl residues
in agriculture and industry. 相似文献
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Nitrate and Fe(III) are two terminal electron acceptors in anaerobic respiration by microorganisms growing in the anoxic soil or sediment environment. In the current paper a facultative anaerobic dissimilatory Fe(III)- and nitrate-reducing bacterium was isolated from the Linchong tailings, a skarn-type copper mine tailings, located in Anhui. Skarn often formed at the contact zone between intrusions of granitic magma bodies into contact with carbonate sedimentary rocks. This made the tailings possessed strong acid neutralizing capacity and pH of the pore water was 6.8–8.6. The isolate, which was designated strain CW (CCTCC AB 2013114), was a gram-negative rod bacterium and belonged to the gamma subgroup p of the proteobacteria, closely (99.0%) related to Pseudomonas stutzeri. In defined medium, strain CW was shown to grow anaerobically with the acetate using the ferric iron or nitrate as the electron acceptors. Results also showed that strain CW could not grow in the presence of ferrous iron and nitrite. 相似文献
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Carrie J. Donovan Rafael A. Gardu?o Martin Kalmokoff John C. Ku Michael A. Quilliam Tom A. Gill 《Applied and environmental microbiology》2009,75(21):6919-6923
Marine bacterial isolates cultured from the digestive tracts of blue mussels (Mytilus edulis) contaminated with paralytic shellfish toxins (PSTs) were screened for the ability to reduce the toxicity of a PST mixture. Seven isolates reduced the overall toxicity of the algal extract by ≥90% within 3 days. These isolates shared at least 99% 16S rRNA gene sequence similarity with five Pseudoalteromonas spp. Phenotypic tests suggested that all are novel strains of Pseudoalteromonas haloplanktis.Among the marine algal biotoxins identified to date; paralytic shellfish toxins (PSTs) constitute the most serious threat to the safety of the food supply, mainly due to their high acute toxicities and the absence of antidotes or effective medical treatments (8). Paralytic shellfish poisoning is caused by ingestion of one or more of the chemically related PSTs (see Fig. S1 in the supplemental material). PSTs are mainly produced by marine dinoflagellates, including Alexandrium spp., Gymnodinium catenatum, and Pyrodinium bahamense var. compresssum (16). Since bivalve molluscs filter-feed on marine algae, they tend to concentrate PSTs largely, but not exclusively, in their digestive organs (7, 9, 10, 29). Not affected by commercial sterilization (14, 18) or cooking, PSTs present significant risks to the food supply, particularly during periods of toxic algal blooms. Practical methods for PST detoxification of living shellfish do not exist (5).Transformations of PSTs by bacteria have been reported in the literature (23-25, 31, 35, 36, 38); early studies focused on the conversion of hydroxysulfate carbamate derivatives (gonyautoxins 1 and 4) to the more highly toxic saxitoxin (STX) (23-25). In addition, several reports have noted the high capacity of the digestive gland for PST transformation (12, 28, 32, 39), suggesting the presence of toxin-transforming enzymes and/or microorganisms in bivalve molluscs. The partial degradation of gonyautoxins 1 and 4 and C1/C2 by marine bacteria has also been reported (38). In addition, Stewart et al. (37) discovered the bacterial degradation of domoic acid (another marine toxin that causes amnesic shellfish poisoning), collectively suggesting that bacteria might play a role in the elimination of marine toxins from toxic bivalve molluscs. The capacity to catabolize domoic acid is greater in cultures isolated from blue mussels that rapidly eliminate domoic acid than in bacterial isolates from bivalves known to retain the toxin for longer time periods (e.g., scallops), suggesting these bacteria play a role in the elimination of marine toxins.Recently, we reported the kinetics of PST destruction for a group of marine bacteria isolated from toxic blue mussels (11). Here we report the phenotypic and taxonomic characterization of these unique marine bacteria. 相似文献
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Isolation and Characterization of a Mycobacterium Species Capable of Degrading Three- and Four-Ring Aromatic and Aliphatic Hydrocarbons 总被引:12,自引:0,他引:12 下载免费PDF全文
Mycobacterium sp. strain CH1 was isolated from polycyclic aromatic hydrocarbon (PAH)-contaminated freshwater sediments and identified by analysis of 16S rDNA sequences. Strain CH1 was capable of mineralizing three- and four-ring PAHs including phenanthrene, pyrene, and fluoranthene. In addition, strain CH1 could utilize phenanthrene or pyrene as a sole carbon and energy source. A lag phase of at least 3 days was observed during pyrene mineralization. This lag phase decreased to less than 1 day when strain CH1 was grown in the presence of phenanthrene or fluoranthene. Strain CH1 also was capable of using a wide range of alkanes as sole carbon and energy sources. No DNA hybridization was detected with the nahAc gene probe, indicating that enzymes involved in PAH metabolism are not related to the well-characterized naphthalene dioxygenase gene. DNA hybridization was not detected when the alkB gene from Pseudomonas oleovorans was used under high-stringency conditions. However, there was slight but detectable hybridization under low-stringency conditions. This suggests a distant relationship between genes involved in alkane oxidation. 相似文献
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Thirty-seven bacterial strains capable of degrading peanut hull lignin were isolated by using four types of lignin preparations and hot-water-extracted peanut hulls. One of the isolates, tentatively identified as Arthrobacter sp., was capable of utilizing all four lignin preparations as well as extracted peanut hulls as a sole source of carbon. The bacterium was also capable of degrading specifically labeled [14C]lignin-labeled lignocellulose and [14C]cellulose-labeled lignocellulose from the cordgrass Spartina alterniflora and could also degrade [14C]Kraft lignin from slash pine. After 10 days of incubation with [14C]cellulose-labeled lignocellulose or [14C]lignin-labeled lignocellulose from S. alterniflora, the bacterium mineralized 6.5% of the polysaccharide component and 2.9% of the lignin component. 相似文献
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敌敌畏降解菌的分离鉴定及降解特性研究 总被引:1,自引:0,他引:1
目的:从受有机磷农药污染的土壤中分离能降解DDVP的菌株,对其进行鉴定和降解特性研究.方法:采用DDVP为惟一碳源和能源的无机盐培养基,通过富集培养、平板划线分离得到一株优势菌,编号为DDW-1,采用形态学、生理生化和16S-rDNA序列分析对其进行鉴定,采用气相色谱测定菌株DDW-1对DDVP的降解能力,并进行底物广谱性测试和降解酶定位实验.结果:该菌株鉴定为甲基杆菌属(Methylobacterium sp.).降解特性试验结果表明,其最佳生长条件为温度28℃,初始pH为7.0,在该条件下,500mg·L-> DDVP经过DDW-1菌株代谢3d后,降解率达63.7%.结论:菌株DDW-1能降解DDVP,该菌株产胞内酶. 相似文献
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《Bioscience, biotechnology, and biochemistry》2013,77(5):932-933
Microorganisms degrading carbazole (CA), a model substrate of heterocyclic nitrogen compounds in crude petroleum oil, were screened under microaerobic conditions, i.e. nitrogen gas substituted conditions. Eight bacteria were isolated and identified. For example, Bacillus sp. KUKK-4 degraded 31 % of CA when cultivated for 28 days in a medium initially containing CA at 1000 mg/l with shaking under the micro aerobic conditions. 相似文献
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Emeka A. Okoroma Diane Purchase Hemda Garelick Roger Morris Michael H. Neale Otto Windl Oduola O. Abiola 《PloS one》2013,8(7)
The prion agent is notoriously resistant to common proteases and conventional sterilisation procedures. The current methods known to destroy prion infectivity such as incineration, alkaline and thermal hydrolysis are harsh, destructive, environmentally polluting and potentially hazardous, thus limit their applications for decontamination of delicate medical and laboratory devices, remediation of prion contaminated environment and for processing animal by-products including specified risk materials and carcases. Therefore, an environmentally friendly, non-destructive enzymatic degradation approach is highly desirable. A feather-degrading Bacillus licheniformis N22 keratinase has been isolated which degraded scrapie prion to undetectable level of PrPSc signals as determined by Western Blot analysis. Prion infectivity was verified by ex vivo cell-based assay. An enzymatic formulation combining N22 keratinase and biosurfactant derived from Pseudomonas aeruginosa degraded PrPSc at 65°C in 10 min to undetectable level -. A time-course degradation analysis carried out at 50°C over 2 h revealed the progressive attenuation of PrPSc intensity. Test of residual infectivity by standard cell culture assay confirmed that the enzymatic formulation reduced PrPSc infectivity to undetectable levels as compared to cells challenged with untreated standard scrapie sheep prion (SSBP/1) (p-value = 0.008 at 95% confidence interval). This novel enzymatic formulation has significant potential application for prion decontamination in various environmentally friendly systems under mild treatment conditions. 相似文献
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一株嗜热菌的分离鉴定及其苯酚降解特性 总被引:14,自引:1,他引:13
从油田地层水中分离到一株嗜热并高效降解苯酚的BF80菌株,其最适生长和降解苯酚的温度为60℃65℃。利用API50CHB/E系统和16SrDNA序列分析对菌株BF80进行了分类鉴定,该菌株的形态和生理生化特性与Geobacillusthermoglucosidasius基本相同,其16SrDNA序列与GeobacillusthermoglucosidasiusBGSCW95A1(=ATCC43742)的相似性为99·22%。在接种量为1%的条件下,该菌在20h内能完全降解3mmol/L的苯酚;在pH值5·59·0范围内能保持对苯酚良好的降解能力,并在12mmol/L苯酚的无机盐培养基中也能生长和降解苯酚,表明该菌能耐受高浓度苯酚并可用于高温含酚废水的生物处理。 相似文献
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新疆艾丁湖中度嗜盐苯酚降解菌多样性研究 总被引:1,自引:0,他引:1
高盐含酚废水属于极难处理的废水之一,筛选具有生物学降解能力的嗜盐菌有助于解决这一难题。从新疆艾丁湖盐湖中分离筛选能够降解苯酚的中度嗜盐菌,了解盐湖中度嗜盐苯酚降解菌的多样性组成和降解能力。研究结果表明,10%(质量分数)的盐浓度条件下,分离得到166株嗜盐菌,通过以苯酚为唯一碳源的培养基进行降解活性筛选后得到45株阳性菌,根据细菌16S rRNA基因序列系统进化分析,这45株菌分别归类到3个门,5个科,9个属。其中拟诺卡氏菌属(Nocardiopsis)是优势菌,占总量的68.8%,其余菌分布于Bacillus、Gracilibacillus、Pontibacillus、Halobacillus、Marinococcus和Halomonas属。在含100 mg/L苯酚的液体培养基,经过10 d培养后,这45株菌降解效率为1%~17%。本研究为工业应用提供了嗜盐微生物种质资源,极具进一步发掘和研究价值。 相似文献
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Isolation,Characterization of a Strain Capable of Degrading Imazethapyr and Its Use in Degradation of the Herbicide in Soil 总被引:1,自引:0,他引:1
Xing Huang Jijie Pan Bo Liang Jiquan Sun Yangyang Zhao Shunpeng Li 《Current microbiology》2009,59(4):363-367
One strain of bacterium IM-4, capable of degrading imazethapyr (IMZT), was isolated from the IMZT-contaminated soil. The isolate
was identified as Pseudomonas sp. according to its physiological characteristics, biochemical tests, and 16S rRNA gene phylogenetic analysis. This strain
could utilize IMZT as the sole carbon and energy source. About 73.4% of the 50 mg l−1 initially added IMZT was degraded after 7 days of inoculation with strain IM-4. This strain also showed the capability to
degrade other imidazolinone herbicides such as imazapyr, imazapic, and imazamox. The inoculation strain IM-4 to soil treated
with IMZT resulted in a higher degradation rate than in noninoculated soil regardless if the soil was sterilized or nonsterilized.
Inoculation of strain IM-4 could also mitigate the phytotoxic effects of IMZT on the growth of maize. 相似文献
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一株苯酚高效降解菌的分离及其分解能力的初步研究 总被引:11,自引:0,他引:11
为了寻找能高效降解苯酚的微生物 ,从武汉市某化工厂周围的下水道污泥中 ,筛选分离出一种具有很高苯酚降解能力的菌株PheD1。通过生理生化及外观鉴定[1~ 3] ,将其初步鉴定为假单胞菌 (Pseudomonassp .)。经驯化后发现 ,该菌生长的迟缓期随苯酚浓度的增大而延长 ,但比同类报道的苯酚降解菌要短 ;在 35℃对数生长期时的苯酚降解率超过同类报道[6 ] ,6 0 0mg·L- 1 苯酚浓度的完全降解时间在 2 4h之内 ,比同类报道[4~ 6 ] 苯酚降解菌的分解能力要高。该菌为好氧菌 ,在空气充足的条件下可提高降解能力。对该菌的继续研究可使其在苯酚的生物降解及污水处理等实际运用中起到重要的作用。 相似文献
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通过正交试验对3种白腐菌混合菌降解竹材木质素的条件进行优化,结果表明,在温度为32℃、pH3.0、固体发酵时间20 d、培养液与竹材基质质量百分比110%时降解木质素的效率最高.在此基础上,研究了两种诱导剂对白腐菌混合菌降解木质素的影响.结果表明,两种诱导剂均能促进木质素的降解,其中H_2O_2在浓度1%时,木质素降解率高达62.9%,苯甲酸在浓度0.1%时,木质素降解率最高,为67.8%. 相似文献