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Sample records for aromatic hydrocarbon-degrading bacteria

  1. Polycyclic aromatic hydrocarbon-degrading bacteria from aviation fuel spill site at Ibeno, Nigeria.

    Science.gov (United States)

    John, R C; Essien, J P; Akpan, S B; Okpokwasili, G C

    2012-06-01

    Polycyclic aromatic hydrocarbon (PAH)-degrading bacteria were isolated from aviation fuel contaminated soil at Inua Eyet Ikot in Ibeno, Nigeria. PAH-degrading bacteria in the contaminated soil were isolated by enrichment culture technique. Isolates with high PAH degrading potential characterized by their extensive growth on PAH-supplemented minimal salt medium were screened for their naphthalene, phenanthrene and chrysene degradability. The screening medium which contained selected PAHs as the sole source of carbon and energy showed that Micrococcus varians AFS-2, Pseudomonas putida AFS-3 and Alcaligenes faecalis AFS-5 exhibited a concentration-dependent growth in all the PAH-compounds tested. There were visible changes in the color of growth medium suggesting the production of different metabolites. Their acclimation to different PAH substrates was also evident as A. faecalis AFS-5 isolated from chrysene grew well on other less complex aromatic compounds. The isolate exhibited best growth (0.44 OD(600)) when exposed to 10 ppm of chrysene for 5 days and could utilize up to 90 ppm of chrysene. This isolate and others with strong PAH-degrading potentials are recommended for bioremediation of PAHs in aviation fuel-contaminated sites in the tropics.

  2. Isolation and characterization of heavy polycyclic aromatic hydrocarbon-degrading bacteria adapted to electrokinetic conditions.

    Science.gov (United States)

    Li, Fengmei; Guo, Shuhai; Hartog, Niels; Yuan, Ye; Yang, Xuelian

    2016-02-01

    Polycyclic aromatic hydrocarbon (PAH)-degrading bacteria capable of growing under electrokinetic conditions were isolated using an adjusted acclimation and enrichment procedure based on soil contaminated with heavy PAHs in the presence of an electric field. Their ability to degrade heavy PAHs under an electric field was individually investigated in artificially contaminated soils. The results showed that strains PB4 (Pseudomonas fluorescens) and FB6 (Kocuria sp.) were the most efficient heavy PAH degraders under electrokinetic conditions. They were re-inoculated into a polluted soil from an industrial site with a PAH concentration of 184.95 mg kg(-1). Compared to the experiments without an electric field, the degradation capability of Pseudomonas fluorescens and Kocuria sp. was enhanced in the industrially polluted soil under electrokinetic conditions. The degradation extents of total PAHs were increased by 15.4 and 14.0% in the electrokinetic PB4 and FB6 experiments (PB4 + EK and FB6 + EK) relative to the PB4 and FB6 experiments without electrokinetic conditions (PB4 and FB6), respectively. These results indicated that P. fluorescens and Kocuria sp. could efficiently degrade heavy PAHs under electrokinetic conditions and have the potential to be used for the electro-bioremediation of PAH-contaminated soil, especially if the soil is contaminated with heavy PAHs.

  3. Hydrocarbon degradation by antarctic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cavanagh, J.A.E.; Nichols, P.D.; McMeekin, T.A.; Franzmann, P.D. [Univ. of Tasmania (Australia)] [and others

    1996-12-31

    Bacterial cultures obtained from sediment samples collected during a trial oil spill experiment conducted at Airport beach, Eastern Antarctica were selectively enriched for n-alkane-degrading and phenanthrenedegrading bacteria. Samples were collected from a control site and sites treated with different hydrocarbon mixtures - Special Antarctic blend (SAB), BP-Visco and orange roughy oils. One set of replicate sites was also treated with water from Organic Lake which had previously been shown to contain hydrocarbon-degrading bacteria. No viable bacteria were obtained from samples collected from sites treated with orange roughy oil. Extensive degradation of n-alkanes by enrichment cultures obtained from sites treated with SAB and BP-Visco occurred at both 25{degrees}C and 10{degrees}C. Extensive degradation of phenanthrene also occurred in enrichment cultures from these sites grown at 25{degrees}C. Concurrent increases of polar lipid in these cultures were also observed. The presence of 1,4-naphthaquinone and 1-naphthol during the growth of the cultures on phenanthrene is unusual and warrants further investigation of the mechanism of phenanthrene-degradation by these Antarctic bacteria.

  4. Hydrocarbon degradation by Antarctic coastal bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cavanagh, J.E. [University of Tasmania, Hobart (Australia). Antarctic Cooperative Research Centre; CSIRO Div of Marine Research, Hobart (Australia); University of Tasmania, Hobart (Australia). Dept. of Agricultural Science; Nichols, P.D. [University of Tasmania, Hobart (Australia). Antarctic Cooperative Research Centre; CSIRO Div. of Marine Research, Hobart (Australia); Franzmann, P.D. [CSIRO Land and Water, Wembley (Australia); McMeekin, T.A. [University of Tasmania, Hobart (Australia). Antarctic Cooperative Research Centre

    1999-07-01

    Bacterial cultures obtained through selective enrichment of beach sand collected 60 days and one year after treatment of sites in a pilot oil spill trial conducted at Airport Beach, Vestfold Hills, East Antarctica, were examined for the ability to degrade n-alkanes and phenanthrene. The effects of different hydrocarbon mixtures (Special Antarctic Blend [SAB] and BP-Visco), (fish oil [orange roughy]) and inoculation of replicate sites with water from Organic Lake, (previously shown to contain hydrocarbon-degrading bacteria) on the indigenous microbial population, were examined. Of the cultures obtained, those from sites treated with SAB and BP-Visco degraded n-alkanes most consistently and typically to the greatest extent. Two mixed cultures obtained from samples collected at 60 days and two isolates obtained from these cultures extensively degraded phenanthrene. 1-Hydroxy-naphthoic acid formed the major phenanthrene metabolite. Lower levels of salicyclic acid, 1-naphthol, 1,4-naphthaquinone and phenanthrene 9-10 dihydrodiol were detected in extracts of phenanthrene grown cultures. This study shows that under laboratory conditions indigenous Antarctica bacteria can degrade n-alkanes and the more recalcitrant polycyclic aromatic hydrocarbon, phenanthrene. The enrichment of hydrocarbon degrading microorganisms in Antarctic ecosystems exposed to hydrocarbons, is relevant for the long term fate of hydrocarbon spills in this environment. (author)

  5. Hydrocarbon Degrading Bacteria: Isolation and Identification

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    Lies Indah Sutiknowati

    2007-11-01

    Full Text Available There is little information how to identify hydrocarbon degrading bacteria for bioremediation of marine oil spills. We have used gravel which contaminated oil mousse from Beach Simulator Tank, in Marine Biotechnology Institute, Kamaishi, Japan, and grown on enrichment culture. Biostimulation with nutrients (N and P was done to analyze biodegradation of hydrocarbon compounds: Naphthalene, Phenanthrene, Trichlorodibenzofuran and Benzo[a]pyrene. Community of bacteria from enrichment culture was determined by DGGE. Isolating and screening the bacteria on inorganic medium contain hydrocarbon compounds and determination of bacteria by DAPI (number of cells and CFU. DNA was extracted from colonies of bacteria and sequence determination of the 16S rDNA was amplified by primers U515f and U1492r. Twenty nine strains had been sequence and have similarity about 90-99% to their closest taxa by homology Blast search and few of them have suspected as new species.

  6. Case study of the relationship between fungi and bacteria associated with high-molecular-weight polycyclic aromatic hydrocarbon degradation.

    Science.gov (United States)

    Wang, Shuozhi; Nomura, Nobuhiko; Nakajima, Toshiaki; Uchiyama, Hiroo

    2012-05-01

    Although bacteria play dominant roles in microbial bioremediation, few of them have been reported that were capable of utilizing high-molecular-weight (HMW) organic pollutants as their sole sources of carbon and energy. However, many soil fungi can metabolize those of pollutants, although they rarely complete mineralization. In this paper, we investigated the dynamic relationship between fungi and bacteria associated with degradation of HMW-polycyclic aromatic hydrocarbons (PAHs). Artificial fungal-bacterial mixed cultures were constructed to simulate the environment of actual polluted sites. Four bacterial strains and seven fungal strains were isolated that related to the removal of phenanthrene, fluoranthene and pyrene in the soil. Furthermore, these strains were used to create mixed culture of bacteria (Bact-mix), mixed culture of fungi (Fung-mix), fungal-bacterial co-cultures (Fung-Bact), respectively. The maximal pyrene removal rate (67%, 28days) was observed in the Fung-Bact, compared with cultures of Fung-mix (39%) and Bact-mix (56%). The same tendency was also indicated in the degradation of phenanthrene and fluoranthene. In addition, a dynamic relationship during the degradation process between fungi and bacteria was monitored through using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) method.

  7. A simple and effective plating method to screen polycyclic aromatic hydrocarbon-degrading bacteria under various redox conditions.

    Science.gov (United States)

    Um, Youngsoon; Chang, Matthew Wook; Holoman, Tracey Pulliam

    2010-09-01

    Agar plates with a polycyclic aromatic hydrocarbon (PAH) layer have been used to screen for microorganisms that degrade PAHs, leaving clear zones around colonies; however, there are several problems with previous methods such as undesired contamination in the fume hood and difficulty in controlling the amount of PAH on the plates. In this study, we developed a modified screening method to address the drawbacks encountered with previous screening methods. A uniform white layer of PAHs was generated by spreading PAHs dissolved in volatile solvents over a surface of solidified agar medium, followed by the evaporation of the solvents. An inoculation was then performed by spreading a molten agar medium containing microbial samples over the solidified agar medium with a PAH layer. Subsequently, the white PAH layer migrated to the surface of the molten agar medium. This essential modification enabled us not only to solve problems of the previous screening methods but also to prepare an agar plate with a PAH layer without a complicated experimental scheme in the anaerobic chamber. After solidification of the molten agar medium and incubation of the plates, clear zones were successfully detected around colonies with aerobic and anaerobic PAH-degrading microbial cultures.

  8. HYDROCARBON-DEGRADING BACTERIA AND SURFACTANT ACTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R; Topher Berry, T; Grazyna A. Plaza, G; jacek Wypych, j

    2006-08-15

    Fate of benzene ethylbenzene toluene xylenes (BTEX) compounds through biodegradation was investigated using two different bacteria, Ralstonia picketti (BP-20) and Alcaligenes piechaudii (CZOR L-1B). These bacteria were isolated from extremely polluted petroleum hydrocarbon contaminated soils. PCR and Fatty Acid Methyl Ester (FAME) were used to identify the isolates. Biodegradation was measured using each organism individually and in combination. Both bacteria were shown to degrade each of the BTEX compounds. Alcaligenes piechaudii biodegraded BTEXs more efficiently while mixed with BP-20 and individually. Biosurfactant production was observed by culture techniques. In addition 3-hydroxy fatty acids, important in biosurfactant production, was observed by FAME analysis. In the all experiments toluene and m+p- xylenes were better growth substrates for both bacteria than the other BTEX compounds. In addition, the test results indicate that the bacteria could contribute to bioremediation of aromatic hydrocarbons (BTEX) pollution increase biodegradation through the action by biosurfactants.

  9. A simple strategy for investigating the diversity and hydrocarbon degradation abilities of cultivable bacteria from contaminated soil.

    Science.gov (United States)

    Bučková, Maria; Puškarová, Andrea; Chovanová, Katarína; Kraková, Lucia; Ferianc, Peter; Pangallo, Domenico

    2013-06-01

    The use of indigenous bacterial strains is a valuable bioremediation strategy for cleaning the environment from hydrocarbon pollutants. The isolation and selection of hydrocarbon-degrading bacteria is therefore crucial for obtaining the most promising strains for site decontamination. Two different media, a minimal medium supplemented with a mixture of polycyclic aromatic hydrocarbons and a MS medium supplemented with triphenyltetrazolium chloride, were used for the isolation of bacterial strains from two hydrocarbon contaminated soils and from their enrichment phases. The hydrocarbon degradation abilities of these bacterial isolates were easily and rapidly assessed using the 2,6-dichlorophenol indophenol assay. The diversity of the bacterial communities isolated from these two soil samples and from their enrichment phases was evaluated by the combination of a bacterial clustering method, fluorescence ITS-PCR, and bacterial identification by 16S rRNA sequencing. Different PCR-based assays were performed in order to detect the genes responsible for hydrocarbon degradation. The best hydrocarbon-degrading bacteria, including Arthrobacter sp., Enterobacter sp., Sphingomonas sp., Pseudomonas koreensis, Pseudomonas putida and Pseudomonas plecoglossicida, were isolated directly from the soil samples on minimal medium. The nahAc gene was detected only in 13 Gram-negative isolates and the sequences of nahAc-like genes were obtained from Enterobacter, Stenotrophomonas, Pseudomonas brenneri, Pseudomonas entomophila and P. koreensis strains. The combination of isolation on minimal medium with the 2,6-dichlorophenol indophenol assay was effective in selecting different hydrocarbon-degrading strains from 353 isolates.

  10. Molecular cloning of novel genes for polycyclic aromatic hydrocarbon degradation from Comamonas testosteroni GZ39.

    OpenAIRE

    1996-01-01

    Three strains of Comamonas testosteroni were isolated from river sediment for the ability to degrade phenanthrene; two of the strains also grew on naphthalene, and one strain also grew on anthracene. The homology of the genes for polycyclic aromatic hydrocarbon degradation in these strains to the classical genes (nah) for naphthalene degradation from Pseudomonas putida NCIB 9816-4 was determined. The three C. testosteroni strains showed no homology to the nah gene probe even under low-stringe...

  11. Succession of hydrocarbon-degrading bacteria in the aftermath of the deepwater horizon oil spill in the gulf of Mexico.

    Science.gov (United States)

    Dubinsky, Eric A; Conrad, Mark E; Chakraborty, Romy; Bill, Markus; Borglin, Sharon E; Hollibaugh, James T; Mason, Olivia U; M Piceno, Yvette; Reid, Francine C; Stringfellow, William T; Tom, Lauren M; Hazen, Terry C; Andersen, Gary L

    2013-10-01

    The Deepwater Horizon oil spill produced large subsurface plumes of dispersed oil and gas in the Gulf of Mexico that stimulated growth of psychrophilic, hydrocarbon degrading bacteria. We tracked succession of plume bacteria before, during and after the 83-day spill to determine the microbial response and biodegradation potential throughout the incident. Dominant bacteria shifted substantially over time and were dependent on relative quantities of different hydrocarbon fractions. Unmitigated flow from the wellhead early in the spill resulted in the highest proportions of n-alkanes and cycloalkanes at depth and corresponded with dominance by Oceanospirillaceae and Pseudomonas. Once partial capture of oil and gas began 43 days into the spill, petroleum hydrocarbons decreased, the fraction of aromatic hydrocarbons increased, and Colwellia, Cycloclasticus, and Pseudoalteromonas increased in dominance. Enrichment of Methylomonas coincided with positive shifts in the δ(13)C values of methane in the plume and indicated significant methane oxidation occurred earlier than previously reported. Anomalous oxygen depressions persisted at plume depths for over six weeks after well shut-in and were likely caused by common marine heterotrophs associated with degradation of high-molecular-weight organic matter, including Methylophaga. Multiple hydrocarbon-degrading bacteria operated simultaneously throughout the spill, but their relative importance was controlled by changes in hydrocarbon supply.

  12. Petroleum Hydrocarbon Degradation Potential of Soil Bacteria Native to the Yellow River Delta

    Institute of Scientific and Technical Information of China (English)

    WANG Zhen-Yu; GAO Dong-Mei; LI Feng-Min; ZHAO Jian; XIN Yuan-Zheng; S.SIMKINS; XING Bao-Shan

    2008-01-01

    The bioremediation potential of bacteria indigenous to soils of the Yellow River Delta in China was evaluated as a treatment option for soil remediation. Petroleum hydrocarbon degraders were isolated from contaminated soil samples from the Yellow River Delta. Four microbial communities and eight isolates were obtained. The optimal temperature, salinity, pH, and the ratios of C, N, and P (C:N:P) for the maximum biodegradation of diesel oil, crude oil, n-alkanes, and polyaromatic hydrocarbons by ndigenous bacteria were determined, and the kinetics changes in microbial communities were monitored. In general, the mixed microbial consortia demonstrated wider catabolic versatility and faster overall rate of hydrocarbon degradation than individual isolates. Our experimental results demonstrated the feasibility of biodegradation of petroleum hydrocarbon by indigenous bacteria for oil remediation in the Yellow River Delta.

  13. Mycobacterium pyrenivorans sp. nov., a novel polycyclic-aromatic-hydrocarbon-degrading species.

    Science.gov (United States)

    Derz, Kerstin; Klinner, Ulrich; Schuphan, Ingolf; Stackebrandt, Erko; Kroppenstedt, Reiner M

    2004-11-01

    The taxonomic position of a polycyclic-aromatic-hydrocarbon-degrading bacterium, strain 17A3(T), isolated from contaminated soil was determined using a combination of phenotypic and genotypic properties. The isolate showed phenotypic properties that were diagnostic for species of the genus Mycobacterium. Comparative 16S rRNA gene sequence analysis assigned 17A3(T) to the 16S rRNA gene subgroup that contains Mycobacterium aurum, Mycobacterium austroafricanum, Mycobacterium vaccae and Mycobacterium vanbaalenii, but it could clearly be distinguished from these species using a combination of physiological, chemotaxonomic markers and internal rRNA gene spacer analyses. The data showed that strain 17A3(T) (=DSM 44605(T)=NRRL B-24244(T)) merits recognition as the type strain of a novel species of the genus Mycobacterium. The name Mycobacterium pyrenivorans sp. nov. is proposed for the species because of its ability to use pyrene as a sole source of carbon and energy.

  14. Hydrocarbon-Degrading Bacteria Exhibit a Species-Specific Response to Dispersed Oil while Moderating Ecotoxicity

    Science.gov (United States)

    Overholt, Will A.; Marks, Kala P.; Romero, Isabel C.; Hollander, David J.; Snell, Terry W.

    2015-01-01

    The Deepwater Horizon blowout in April 2010 represented the largest accidental marine oil spill and the largest release of chemical dispersants into the environment to date. While dispersant application may provide numerous benefits to oil spill response efforts, the impacts of dispersants and potential synergistic effects with crude oil on individual hydrocarbon-degrading bacteria are poorly understood. In this study, two environmentally relevant species of hydrocarbon-degrading bacteria were utilized to quantify the response to Macondo crude oil and Corexit 9500A-dispersed oil in terms of bacterial growth and oil degradation potential. In addition, specific hydrocarbon compounds were quantified in the dissolved phase of the medium and linked to ecotoxicity using a U.S. Environmental Protection Agency (EPA)-approved rotifer assay. Bacterial treatment significantly and drastically reduced the toxicity associated with dispersed oil (increasing the 50% lethal concentration [LC50] by 215%). The growth and crude oil degradation potential of Acinetobacter were inhibited by Corexit by 34% and 40%, respectively; conversely, Corexit significantly enhanced the growth of Alcanivorax by 10% relative to that in undispersed oil. Furthermore, both bacterial strains were shown to grow with Corexit as the sole carbon and energy source. Hydrocarbon-degrading bacterial species demonstrate a unique response to dispersed oil compared to their response to crude oil, with potentially opposing effects on toxicity. While some species have the potential to enhance the toxicity of crude oil by producing biosurfactants, the same bacteria may reduce the toxicity associated with dispersed oil through degradation or sequestration. PMID:26546426

  15. Distribution of hydrocarbon-degrading bacteria in the soil environment and their contribution to bioremediation.

    Science.gov (United States)

    Fukuhara, Yuki; Horii, Sachie; Matsuno, Toshihide; Matsumiya, Yoshiki; Mukai, Masaki; Kubo, Motoki

    2013-05-01

    A real-time PCR quantification method for indigenous hydrocarbon-degrading bacteria (HDB) carrying the alkB gene in the soil environment was developed to investigate their distribution in soil. The detection limit of indigenous HDB by the method was 1 × 10(6) cells/g-soil. The indigenous HDB were widely distributed throughout the soil environment and ranged from 3.7 × 10(7) to 5.0 × 10(8) cells/g-soil, and the ratio to total bacteria was 0.1-4.3 %. The dynamics of total bacteria, indigenous HDB, and Rhodococcus erythropolis NDKK6 (carrying alkB R2) during bioremediation were analyzed. During bioremediation with an inorganic nutrient treatment, the numbers of these bacteria were slightly increased. The numbers of HDB (both indigenous bacteria and strain NDKK6) were gradually decreased from the middle stage of bioremediation. Meanwhile, the numbers of these bacteria were highly increased and were maintained during bioremediation with an organic nutrient. The organic treatment led to activation of not only the soil bacteria but also the HDB, so an efficient bioremediation was carried out.

  16. Cultivation-dependent and cultivation-independent characterisation of hydrocarbon-degrading bacteria in Guaymas Basin sediments

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    Tony eGutierrez

    2015-07-01

    Full Text Available Marine hydrocarbon-degrading bacteria perform a fundamental role in the biodegradation of crude oil and its petrochemical derivatives in coastal and open ocean environments. However, there is a paucity of knowledge on the diversity and function of these organisms in deep-sea sediment. Here we used stable-isotope probing (SIP, a valuable tool to link the phylogeny and function of targeted microbial groups, to investigate polycyclic aromatic hydrocarbon (PAH-degrading bacteria under aerobic conditions in sediments from Guaymas Basin with uniformly labeled [13C]phenanthrene. The dominant sequences in clone libraries constructed from 13C-enriched bacterial DNA (from phenanthrene enrichments were identified to belong to the genus Cycloclasticus. We used quantitative PCR primers targeting the 16S rRNA gene of the SIP-identified Cycloclasticus to determine their abundance in sediment incubations amended with unlabeled phenanthrene and showed substantial increases in gene abundance during the experiments. We also isolated a strain, BG-2, representing the SIP-identified Cycloclasticus sequence (99.9% 16S rRNA gene sequence identity, and used this strain to provide direct evidence of phenanthrene degradation and mineralization. In addition, we isolated Halomonas, Thalassospira and Lutibacterium spp. with demonstrable phenanthrene-degrading capacity from Guaymas Basin sediment. This study demonstrates the value of coupling SIP with cultivation methods to identify and expand on the known diversity of PAH-degrading bacteria in the deep-sea.

  17. Aquatic Organisms and Petroleum Hydrocarbon Degrading Bacteria Associated with Their Digestive System

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    Janina Šyvokienė

    2013-12-01

    Full Text Available Laboratory investigation was carried out on the abundance and composition of bacteria in the digestive system of a total of 35 specimens, including bivalve molluscs, i.e. swan mussel Anodonta cygnea (Linnaeus, 1758 from Lake Spėra (Širvintos district and swollen river mussel Unio tumidus (Philipson, 1788 from the Curonian Lagoon near Juodkrantė, zebra mussel (Dreissena polymorpha from the Curonian Lagoon near Juodkrantė and an anostracan – Chirocephalus josephinae (Grube, 1853 from a pond in Ilčiukai village, Utena district, and in the water of related water bodies. Studies on bivalve molluscs (swan mussel and swollen river mussel, zebra mussel and an anostracan – Chirocephalus josephinae, as well as microbiological investigation of water demonstrated that the number of microorganisms in the digestive system of mollusc and anostracan species fluctuated and varied between different species and water bodies. The greatest percentage of HDB among total heterotrophic bacteria was found in the digestive system of swollen river mussels (21.53% and in zebra mussels (19.99% caught in the Curonian Lagoon and in the water of the lagoon (24%. A considerably smaller percentage of HDB was detected in the digestive system of swan mussels from Lake Spėra (17.6% and in the water of the lake (16.66%. The smallest percentage of HDB was found in the digestive system of Chirocephalus josephinae (6.63% and in the water of the Ilčiukai pond (2.72%. According to the values of abundance of petroleum hydrocarbon-degrading bacteria (HDB and total coliform bacteria (TCFB in the digestive system of aquatic organisms we can state that the water ecosystem of Ilčiukai pond was the least contaminated with petroleum, its products and sewage water, and the Curonian Lagoon water ecosystem was the most contaminated. Abundance of petroleum hydrocarbons degrading bacteria could be used as a bioindicator reflecting the level of ecosystem pollution petroleum and its

  18. Exploration of hydrocarbon degrading bacteria on soils contaminated by crude oil from South Sumatera

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    A. Napoleon

    2014-07-01

    Full Text Available The goal of this research was to explore hydrocarbon degrading bacteria on crude oil contaminated soil with potential to degrade hydrocarbon in oil pollutant. The research started by early August 2013 till January 2014. Soil sampling for this research was taken on several places with contaminated soil location such as Benakat, Rimau, and Pengabuan all of it located in South Sumatera. Conclusion from this research Isolates obtained from three (3 sites of contaminated soil and treated using SBS medium were Bacillus cereus, Pseudomonas aeruginosa, Klebsiella pnumoniae, Streptococcus beta hemolisa, Proteus mirabilis, Staphylococcus epidermis and Acinotobacter calcoaceticus. Isolates that survived on 300 ppm of hydrocarbon concentration were Bacillus cereus, Pseudomonas aeruginosa and Acinetobacter cakciaceticus Selected isolates posses the ability to degrade hydrocarbon by breaking hydrocarbon substance as the energy source to support isolates existence up to 1,67 TPH level. Based on results accomplish by this research, we urge for further research involving the capacity of isolates to degrade wide variety of hydrocarbon substance and more to develop the potential of these bacteria for bioremediation.

  19. A Review on the Genetics of Aliphatic and Aromatic Hydrocarbon Degradation.

    Science.gov (United States)

    Abbasian, Firouz; Lockington, Robin; Megharaj, Mallavarapu; Naidu, Ravi

    2016-01-01

    Because of the high diversity of hydrocarbons, degradation of each class of these compounds is activated by a specific enzyme. However, most of other downstream enzymes necessary for complete degradation of hydrocarbons maybe common between different hydrocarbons. The genes encoding proteins for degradation of hydrocarbons, including the proteins required for the uptake of these molecules, the specific enzyme used for the initial activation of the molecules and other necessary degrading enzymes are usually arranged as an operon. Although the corresponding genes in many phylogenetic groups of microbial species show different levels of diversity in terms of the gene sequence, the organisation of the genes in the genome or on plasmids and the activation mode (inductive or constitutive), some organisms show identical hydrocarbon-degrading genes, probably as a result of horizontal gene transfer between microorganisms.

  20. Bioremediation of coastal areas 5 years after the Nakhodka oil spill in the Sea of Japan: isolation and characterization of hydrocarbon-degrading bacteria.

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    Chaerun, S Khodijah; Tazaki, Kazue; Asada, Ryuji; Kogure, Kazuhiro

    2004-09-01

    Five years after the 1997 Nakhodka oil spill in the Sea of Japan, seven bacterial strains capable of utilizing the heavy oil spilled from the Nakhodka Russian oil tanker were isolated from three coastal areas (namely Katano Seashore of Fukui Prefecture, Osawa and Atake seashores of Ishikawa Prefecture) and the Nakhodka Russian oil tanker after a 5-year bioremediation process. All bacterial strains isolated could utilize long-chain-length alkanes efficiently, but not aromatic, and all of them were able to grow well on heavy oil. Using 16S rDNA sequencing, most of the strains were affiliated to Pseudomonas aeruginosa. Comparing between the year 1997 (at the beginning of bioremediation process) and the year 2001 (after 5 years of bioremediation), there was no significant change in morphology and size of hydrocarbon-degrading bacteria during the 5-year bioremediation. Scanning and transmission electron microscopic observations revealed that a large number of hydrocarbon-degrading bacteria still existed in the sites consisting of a variety of morphological forms of bacteria, such as coccus (Streptococcus and Staphylococcus) and bacillus (Streptobacillus). On the application of bioremediation processes on the laboratory-scale, laboratory microcosm experiments (containing seawater, beach sand, and heavy oil) under aerobic condition by two different treatments (i.e., placed the inside building and the outside building) were established for bioremediation of heavy oil to investigate the significance of the role of hydrocarbon-degrading bacteria on them. There was no significant bacterial activity differentiation in the two treatments, and removal of heavy oil by hydrocarbon-degrading bacteria in the outside building was slightly greater than that in the inside building. The values of pH, Eh, EC, and dissolved oxygen (DO) in two treatments indicated that the bioremediation process took place under aerobic conditions (DO: 1-6 mg/l; Eh: 12-300 mV) and neutral

  1. Bioremediation of coastal areas 5 years after the Nakhodka oil spill in the Sea of Japan: isolation and characterization of hydrocarbon-degrading bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Chaerun, S. Khodijah [Kanazawa Univ., Graduate School of Natural Science and Technology, Kanazawa (Japan); Tazaki, Kazue; Asada, Ryuji [Kanazawa Univ., Dept. of Earth Sciences, Kanazawa (Japan); Kogure, Kazuhiro [Tokyo Univ., Ocean Research Inst., Nakano, Tokyo (Japan)

    2004-09-01

    Five years after the 1997 Nakhodka oil spill in the Sea of Japan, seven bacterial strains capable of utilizing the heavy oil spilled from the Nakhodka Russian oil tanker were isolated from three coastal areas (namely Katano Seashore of Fukui Prefecture, Osawa and Atake seashores of Ishikawa Prefecture) and the Nakhodka Russian oil tanker after a 5-year bioremediation process. All bacterial strains isolated could utilize long-chain-length alkanes efficiently, but not aromatic, and all of them were able to grow well on heavy oil. Using 16S rDNA sequencing, most of the strains were affiliated to Pseudomonas aeruginosa. Comparing between the year 1997 (at the beginning of bioremediation process) and the year 2001 (after 5 years of bioremediation), there was no significant change in morphology and size of hydrocarbon-degrading bacteria during the 5-year bioremediation. Scanning and transmission electron microscopic observations revealed that a large number of hydrocarbon- degrading bacteria still existed in the sites consisting of a variety of morphological forms of bacteria, such as coccus (Streptococcus and Staphylococcus) and bacillus (Streptobacillus). On the application of bioremediation processes on the laboratory-scale, laboratory microcosm experiments (containing seawater, beach sand, and heavy oil) under aerobic condition by two different treatments (i.e., placed inside the building and outside the building) were established for bioremediation of heavy oil to investigate the significance of the role of hydrocarbon-degrading bacteria on them. There was no significant bacterial activity differentiation in the two treatments, and removal of heavy oil by hydrocarbon degrading bacteria in the outside building was slightly greater than that in the inside building. The values of pH, Eh, EC, and dissolved oxygen (DO) in two treatments indicated that the bioremediation process took place under aerobic conditions (DO: 1-6 mg/l; Eh: 12-300 mV) and neutral

  2. Draft Genome Sequence of Marinobacter hydrocarbonoclasticus Strain STW2, a Polycyclic Aromatic Hydrocarbon-Degrading and Denitrifying Bacterium from the Rhizosphere of Seagrass Enhalus acodoides

    Science.gov (United States)

    Ling, Juan; Lin, Liyun; Zhang, Yanying; Lin, Xiancheng; Ahamad, Manzoor; Zhou, Weiguo

    2017-01-01

    ABSTRACT Here, we report the draft genome sequence of Marinobacter hydrocarbonoclasticus strain STW2, which was isolated from the rhizosphere of seagrass Enhalus acodoides. This study will facilitate future studies on the genetic pathways of marine microbes capable of both polycyclic aromatic hydrocarbon degradation and nitrate reduction. PMID:28232431

  3. Potential of Polycyclic Aromatic Hydrocarbon-Degrading Bacterial Isolates to Contribute to Soil Fertility

    Science.gov (United States)

    Chirima, George Johannes

    2016-01-01

    Restoration of polycyclic aromatic hydrocarbon- (PAH-) polluted sites is presently a major challenge in agroforestry. Consequently, microorganisms with PAH-degradation ability and soil fertility improvement attributes are sought after in order to achieve sustainable remediation of polluted sites. This study isolated PAH-degrading bacteria from enriched cultures of spent automobile engine-oil polluted soil. Isolates' partial 16S rRNA genes were sequenced and taxonomically classified. Isolates were further screened for their soil fertility attributes such as phosphate solubilization, atmospheric nitrogen fixation, and indoleacetic acid (IAA) production. A total of 44 isolates were obtained and belong to the genera Acinetobacter, Arthrobacter, Bacillus, Flavobacterium, Microbacterium, Ochrobactrum, Pseudomonas, Pseudoxanthomonas, Rhodococcus, and Stenotrophomonas. Data analysed by principal component analysis showed the Bacillus and Ochrobactrum isolates displayed outstanding IAA production. Generalized linear modelling statistical approaches were applied to evaluate the contribution of the four most represented genera (Pseudomonas, Acinetobacter, Arthrobacter, and Rhodococcus) to soil fertility. The Pseudomonas isolates were the most promising in all three soil fertility enhancement traits evaluated and all isolates showed potential for one or more of the attributes evaluated. These findings demonstrate a clear potential of the isolates to participate in restorative bioremediation of polluted soil, which will enhance sustainable agricultural production and environmental protection. PMID:27774456

  4. Potential of Polycyclic Aromatic Hydrocarbon-Degrading Bacterial Isolates to Contribute to Soil Fertility

    Directory of Open Access Journals (Sweden)

    Maryam Bello-Akinosho

    2016-01-01

    Full Text Available Restoration of polycyclic aromatic hydrocarbon- (PAH- polluted sites is presently a major challenge in agroforestry. Consequently, microorganisms with PAH-degradation ability and soil fertility improvement attributes are sought after in order to achieve sustainable remediation of polluted sites. This study isolated PAH-degrading bacteria from enriched cultures of spent automobile engine-oil polluted soil. Isolates’ partial 16S rRNA genes were sequenced and taxonomically classified. Isolates were further screened for their soil fertility attributes such as phosphate solubilization, atmospheric nitrogen fixation, and indoleacetic acid (IAA production. A total of 44 isolates were obtained and belong to the genera Acinetobacter, Arthrobacter, Bacillus, Flavobacterium, Microbacterium, Ochrobactrum, Pseudomonas, Pseudoxanthomonas, Rhodococcus, and Stenotrophomonas. Data analysed by principal component analysis showed the Bacillus and Ochrobactrum isolates displayed outstanding IAA production. Generalized linear modelling statistical approaches were applied to evaluate the contribution of the four most represented genera (Pseudomonas, Acinetobacter, Arthrobacter, and Rhodococcus to soil fertility. The Pseudomonas isolates were the most promising in all three soil fertility enhancement traits evaluated and all isolates showed potential for one or more of the attributes evaluated. These findings demonstrate a clear potential of the isolates to participate in restorative bioremediation of polluted soil, which will enhance sustainable agricultural production and environmental protection.

  5. Assessing the hydrocarbon degrading potential of indigenous bacteria isolated from crude oil tank bottom sludge and hydrocarbon-contaminated soil of Azzawiya oil refinery, Libya.

    Science.gov (United States)

    Mansur, Abdulatif A; Adetutu, Eric M; Kadali, Krishna K; Morrison, Paul D; Nurulita, Yuana; Ball, Andrew S

    2014-09-01

    The disposal of hazardous crude oil tank bottom sludge (COTBS) represents a significant waste management burden for South Mediterranean countries. Currently, the application of biological systems (bioremediation) for the treatment of COTBS is not widely practiced in these countries. Therefore, this study aims to develop the potential for bioremediation in this region through assessment of the abilities of indigenous hydrocarbonoclastic microorganisms from Libyan Hamada COTBS for the biotreatment of Libyan COTBS-contaminated environments. Bacteria were isolated from COTBS, COTBS-contaminated soil, treated COTBS-contaminated soil, and uncontaminated soil using Bushnell Hass medium amended with Hamada crude oil (1 %) as the main carbon source. Overall, 49 bacterial phenotypes were detected, and their individual abilities to degrade Hamada crude and selected COBTS fractions (naphthalene, phenanthrene, eicosane, octadecane and hexane) were evaluated using MT2 Biolog plates. Analyses using average well colour development showed that ~90 % of bacterial isolates were capable of utilizing representative aromatic fractions compared to 51 % utilization of representative aliphatics. Interestingly, more hydrocarbonoclastic isolates were obtained from treated contaminated soils (42.9 %) than from COTBS (26.5 %) or COTBS-contaminated (30.6 %) and control (0 %) soils. Hierarchical cluster analysis (HCA) separated the isolates into two clusters with microorganisms in cluster 2 being 1.7- to 5-fold better at hydrocarbon degradation than those in cluster 1. Cluster 2 isolates belonged to the putative hydrocarbon-degrading genera; Pseudomonas, Bacillus, Arthrobacter and Brevundimonas with 57 % of these isolates being obtained from treated COTBS-contaminated soil. Overall, this study demonstrates that the potential for PAH degradation exists for the bioremediation of Hamada COTBS-contaminated environments in Libya. This represents the first report on the isolation of

  6. Bacterial Community Dynamics and Polycyclic Aromatic Hydrocarbon Degradation during Bioremediation of Heavily Creosote-Contaminated Soil

    OpenAIRE

    Viñas, Marc; Sabaté, Jordi; Espuny, María José; Solanas, Anna M.

    2005-01-01

    Bacterial community dynamics and biodegradation processes were examined in a highly creosote-contaminated soil undergoing a range of laboratory-based bioremediation treatments. The dynamics of the eubacterial community, the number of heterotrophs and polycyclic aromatic hydrocarbon (PAH) degraders, and the total petroleum hydrocarbon (TPH) and PAH concentrations were monitored during the bioremediation process. TPH and PAHs were significantly degraded in all treatments (72 to 79% and 83 to 87...

  7. Functional diversity of bacterial genes associated with aromatic hydrocarbon degradation in anthropogenic dark earth of Amazonia

    Directory of Open Access Journals (Sweden)

    Mariana Gomes Germano

    2012-05-01

    Full Text Available The objective of this work was to evaluate the catabolic gene diversity for the bacterial degradation of aromatic hydrocarbons in anthropogenic dark earth of Amazonia (ADE and their biochar (BC. Functional diversity analyses in ADE soils can provide information on how adaptive microorganisms may influence the fertility of soils and what is their involvement in biogeochemical cycles. For this, clone libraries containing the gene encoding for the alpha subunit of aromatic ring-hydroxylating dioxygenases (α-ARHD bacterial gene were constructed, totaling 800 clones. These libraries were prepared from samples of an ADE soil under two different land uses, located at the Caldeirão Experimental Station - secondary forest (SF and agriculture (AG -, and the biochar (SF_BC and AG_BC, respectively. Heterogeneity estimates indicated greater diversity in BC libraries; and Venn diagrams showed more unique operational protein clusters (OPC in the SF_BC library than the ADE soil, which indicates that specific metabolic processes may occur in biochar. Phylogenetic analysis showed unidentified dioxygenases in ADE soils. Libraries containing functional gene encoding for the alpha subunit of the aromatic ring-hydroxylating dioxygenases (ARHD gene from biochar show higher diversity indices than those of ADE under secondary forest and agriculture.

  8. The polycyclic aromatic hydrocarbon degradation potential of Gulf of Mexico native coastal microbial communities after the Deepwater Horizon oil spill.

    Science.gov (United States)

    Kappell, Anthony D; Wei, Yin; Newton, Ryan J; Van Nostrand, Joy D; Zhou, Jizhong; McLellan, Sandra L; Hristova, Krassimira R

    2014-01-01

    The Deepwater Horizon (DWH) blowout resulted in oil transport, including polycyclic aromatic hydrocarbons (PAHs) to the Gulf of Mexico shoreline. The microbial communities of these shorelines are thought to be responsible for the intrinsic degradation of PAHs. To investigate the Gulf Coast beach microbial community response to hydrocarbon exposure, we examined the functional gene diversity, bacterial community composition, and PAH degradation capacity of a heavily oiled and non-oiled beach following the oil exposure. With a non-expression functional gene microarray targeting 539 gene families, we detected 28,748 coding sequences. Of these sequences, 10% were uniquely associated with the severely oil-contaminated beach and 6.0% with the non-oiled beach. There was little variation in the functional genes detected between the two beaches; however the relative abundance of functional genes involved in oil degradation pathways, including polycyclic aromatic hydrocarbons (PAHs), were greater in the oiled beach. The microbial PAH degradation potentials of both beaches, were tested in mesocosms. Mesocosms were constructed in glass columns using sands with native microbial communities, circulated with artificial sea water and challenged with a mixture of PAHs. The low-molecular weight PAHs, fluorene and naphthalene, showed rapid depletion in all mesocosms while the high-molecular weight benzo[α]pyrene was not degraded by either microbial community. Both the heavily oiled and the non-impacted coastal communities showed little variation in their biodegradation ability for low molecular weight PAHs. Massively-parallel sequencing of 16S rRNA genes from mesocosm DNA showed that known PAH degraders and genera frequently associated with oil hydrocarbon degradation represented a major portion of the bacterial community. The observed similar response by microbial communities from beaches with a different recent history of oil exposure suggests that Gulf Coast beach communities are

  9. Polycyclic aromatic hydrocarbon degradation by biosurfactant-producing Pseudomonas sp. IR1

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, M. [Unidad de Biotecnologia del Petroleo, Centro de Biotecnologia, Fundacion Inst. de Estudios Avanzados (IDEA), Caracas (Venezuela); Synthesis and Biotics Div., Indian Oil Corp., Research and Development Center, Haryana (India); Leon, V.; Materano, A.D.S.; Ilzins, O.A.; Galindo-Castro, I.; Fuenmayor, S.L. [Unidad de Biotecnologia del Petroleo, Centro de Biotecnologia, Fundacion Inst. de Estudios Avanzados (IDEA), Caracas (Venezuela)

    2006-03-15

    We characterized a newly isolated bacterium, designated as IR1, with respect to its ability to degrade polycyclic aromatic hydrocarbons (PAHs) and to produce biosurfactants. Isolated IR1 was identified as Pseudomonas putida by analysis of 16S rRNA sequences (99.6% homology). It was capable of utilizing two-, three- and four-ring PAHs but not hexadecane and octadecane as a sole carbon and energy source. PCR and DNA hybridization studies showed that enzymes involved in PAH metabolism were related to the naphthalene dioxygenase pathway. Observation of both tensio-active and emulsifying activities indicated that biosurfactants were produced by IR1 during growth on both water miscible and immiscible substrates. The biosurfactants lowered the surface tension of medium from 54.9 dN cm{sup -1} to 35.4 dN cm{sup -1} and formed a stable and compact emulsion with an emulsifying activity of 74% with diesel oil, when grown on dextrose. These findings indicate that this isolate may be useful for bioremediation of sites contaminated with aromatic hydrocarbons. (orig.)

  10. Prediction of mono- and polycyclic aromatic hydrocarbon degradation in spiked soils using cyclodextrin extraction

    Energy Technology Data Exchange (ETDEWEB)

    Allan, Ian J. [School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ (United Kingdom); Semple, Kirk T. [Department of Environmental Sciences, Lancaster University, LA1 4YQ (United Kingdom); Hare, Rina [Alcontrol Laboratories, Chester CH5 3US (United Kingdom); Reid, Brian J. [Alcontrol Laboratories, Chester CH5 3US (United Kingdom)]. E-mail: b.reid@uea.ac.uk

    2006-11-15

    In this study, an aqueous-based hydroxypropyl-{beta}-cyclodextrin (HPCD) extraction technique was assessed for its capacity to determine the microbially degradable fraction of mono- and polycyclic aromatic hydrocarbons in four dissimilar soils. A linear relationship (slope = 0.90; R {sup 2} = 0.89), approaching 1:1 between predicted and observed phenanthrene mineralization, was demonstrated for the cyclodextrin extraction; however, the water only extraction underestimated the microbially available fraction by a factor of three (slope = 3.35; R {sup 2} = 0.64). With respect to determining the mineralizable fraction of p-cresol in soils, the cyclodextrin extraction (slope = 0.94; R {sup 2} = 0.84) was more appropriate than the water extraction (slope = 1.50; R {sup 2} = 0.36). Collectively, these results suggested that the cyclodextrin extraction technique was suitable for the prediction of the mineralizable fraction of representative PAHs and phenols present in dissimilar soils following increasing soil-contaminant contact times. The assessment of the microbial availability of contaminants in soils is important for a more representative evaluation of soil contamination. - An aqueous-based HPCD extraction technique was more appropriate than the water extraction in prediction of the mineralizable fraction of phenanthrene and p-cresol present in a range of dissimilar soils.

  11. Polynuclear aromatic hydrocarbon degradation by heterogeneous reactions with N 2O 5 on atmospheric particles

    Science.gov (United States)

    Kamens, Richard M.; Guo, Jiazhen; Guo, Zhishi; McDow, Stephen R.

    The degradation of particulate polynuclear aromatic hydrocarbons (PAH) on atmospheric soot particles in the presence of gas phase dinitrogen pentoxide (N 2O 5) was explored. Dilute diesel and wood soot particles containing PAH were reacted with˜10ppm of N 2O 5 in a 200 ℓ continuous stirred tank reactor (CSTR). To provide a stable source of particles for reaction in the CSTR, diesel or wood soot particles were injected at night into a 25 m 3 Teflon outdoor chamber. The large chamber served as a reservoir for the feed aerosol, and the aerosol could then be introduced at a constant flow rate into the CSTR. PAH-N 2O 5 heterogeneous rate constants for wood soot at 15°C ranged from2 × 10 -18to5 × 10 -18 cm 3 molecules -1 s -1. For diesel soot the rate constants at 16°C were higher and ranged from5 × 10 -18to30 × 10 -18 cm 3 molecules -1 s -1. Comparisons with other studies suggest that sunlight is the most important factor which influences PAH decay. This is followed by ozone, NO 2, N 2O 5 and nitric acid. The rate constants of nitro-PAH formation from a parent PAH and N 2O 5 were of the order of1 × 10 -19-1 × 10 -18 molecules -1s -1. The uncertainty associated with all of these rate constants is± a factor of 3. Given, however, the small magnitude of the rate constants and the low levels of N 2O 5 present in the atmosphere, we concluded that PAH heterogeneous reactions with gas phase N 2O 5 degrade particle-bound PAH or to form nitro-PAH from PAH are not very important. (Direct application of the specific rate constants derived in this study to ambient atmospheres should not be undertaken unless the ambient particle size distributions and chemical composition of the particles are similar to the ones reported in this study.)

  12. The polycyclic aromatic hydrocarbon degradation potential of Gulf of Mexico coastal microbial communities after the Deepwater Horizon oil spill

    Directory of Open Access Journals (Sweden)

    Anthony D. Kappell

    2014-05-01

    Full Text Available The Deepwater Horizon (DWH blowout resulted in oil transport, including polycyclic aromatic hydrocarbons (PAHs to the Gulf of Mexico shoreline. The microbial communities of these shorelines are thought to be responsible for the intrinsic degradation of PAHs. To investigate the Gulf Coast beach microbial community response to hydrocarbon exposure, we examined the functional gene diversity, bacterial community composition, and PAH degradation capacity of a heavily oiled and non-oiled beach following the oil exposure. With a non-expression functional gene microarray targeting 539 gene families, we detected 28,748 coding sequences. Of these sequences, 10% were uniquely associated with the severely oil-contaminated beach and 6.0% with the non-oiled beach. There was little variation in the functional genes detected between the two beaches; however the relative abundance of functional genes involved in oil degradation pathways, including PAHs, were greater in the oiled beach. The microbial PAH degradation potentials of both beaches, were tested in mesocosms. Mesocosms were constructed in glass columns using sands with native microbial communities, circulated with artificial sea water and challenged with a mixture of PAHs. The low-molecular weight PAHs, fluorene and naphthalene, showed rapid depletion in all mesocosms while the high-molecular weight benzo[α]pyrene was not degraded by either microbial community. Both the heavily oiled and the non-impacted coastal communities showed little variation in their biodegradation ability for low molecular weight PAHs. Massively-parallel sequencing of 16S rRNA genes from mesocosm DNA showed that known PAH degraders and genera frequently associated with oil hydrocarbon degradation represented a major portion of the bacterial community. The observed similar response by microbial communities from beaches with a different recent history of oil exposure suggests that Gulf Coast beach communities are primed for PAH

  13. Polycyclic aromatic hydrocarbons degradation and microbial community shifts during co-composting of creosote-treated wood.

    Science.gov (United States)

    Covino, Stefano; Fabianová, Tereza; Křesinová, Zdena; Čvančarová, Monika; Burianová, Eva; Filipová, Alena; Vořísková, Jana; Baldrian, Petr; Cajthaml, Tomáš

    2016-01-15

    The feasibility of decontaminating creosote-treated wood (CTW) by co-composting with agricultural wastes was investigated using two bulking agents, grass cuttings (GC) and broiler litter (BL), each employed at a 1:1 ratio with the matrix. The initial concentration of total polycyclic aromatic hydrocarbons (PAHs) in CTW (26,500 mg kg(-1)) was reduced to 3 and 19% after 240 d in GC and BL compost, respectively. PAH degradation exceeded the predicted bioaccesible threshold, estimated through sequential supercritical CO2 extraction, together with significant detoxification, assessed by contact tests using Vibrio fisheri and Hordeum vulgare. GC composting was characterized by high microbial biomass growth in the early phases, as suggested by phospholipid fatty acid analyses. Based on the 454-pyrosequencing results, fungi (mostly Saccharomycetales) constituted an important portion of the microbial community, and bacteria were characterized by rapid shifts (from Firmicutes (Bacilli) and Actinobacteria to Proteobacteria). However, during BL composting, larger amounts of prokaryotic and eukaryotic PLFA markers were observed during the cooling and maturation phases, which were dominated by Proteobacteria and fungi belonging to the Ascomycota and those putatively related to the Glomeromycota. This work reports the first in-depth analysis of the chemical and microbiological processes that occur during the co-composting of a PAH-contaminated matrix.

  14. Hydrocarbon-Degrading Bacteria and Paraffin from Polluted Seashores 9 Years after the Nakhodka Oil Spill in the Sea of Japan

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Pollution of petroleum hydrocarbons, in particular oil spills, has attracted much attention in the past and recent decades. Oil spills influence natural microbial community, and physical and chemical properties of the affected sites. The biodegradation of hydrocarbons by microorganisms is one of the primary ways by which oil spill is eliminated from contaminated sites. One such spill was that of the Russian tanker the Nakhodka that spilled heavy oil into the Sea of Japan on January 2, 1997. The impact of the Nakhodka oil spill resulted in a viscous sticky fluid fouling the shores and affected natural ecosystems. This paper describes the weathering of hydrocarbon-degrading bacteria (genus Pseudomonas) and crystallized organic compounds from the Nakhodka oil spill-polluted seashores after nine years. The Nakhodka oil has hardened and formed crust of crystalline paraffin wax as shown by XRD analysis (0.422, 0.377, and 0.250 nm d-spacing) in association with graphite and calcite after 9years of bioremediation. Anaerobic reverse side of the oil crust contained numerous coccus typed bacteria associated with halite. The finding of hydrocarbon-degrading bacteria and paraffin wax in the oil crust may have a significant effect on the weathering processes of the Nakhodka oil spill during the 9-year bioremediation.

  15. Genomic insights into the metabolic potential of the polycyclic aromatic hydrocarbon degrading sulfate-reducing Deltaproteobacterium N47.

    Science.gov (United States)

    Bergmann, Franz; Selesi, Draženka; Weinmaier, Thomas; Tischler, Patrick; Rattei, Thomas; Meckenstock, Rainer U

    2011-05-01

    Anaerobic degradation of polycyclic aromatic hydrocarbons (PAHs) is an important process during natural attenuation of aromatic hydrocarbon spills. However, knowledge about metabolic potential and physiology of organisms involved in anaerobic degradation of PAHs is scarce. Therefore, we introduce the first genome of the sulfate-reducing Deltaproteobacterium N47 able to catabolize naphthalene, 2-methylnaphthalene, or 2-naphthoic acid as sole carbon source. Based on proteomics, we analysed metabolic pathways during growth on PAHs to gain physiological insights on anaerobic PAH degradation. The genomic assembly and taxonomic binning resulted in 17 contigs covering most of the sulfate reducer N47 genome according to general cluster of orthologous groups (COGs) analyses. According to the genes present, the Deltaproteobacterium N47 can potentially grow with the following sugars including d-mannose, d-fructose, d-galactose, α-d-glucose-1P, starch, glycogen, peptidoglycan and possesses the prerequisites for butanoic acid fermentation. Despite the inability for culture N47 to utilize NO(3) (-) as terminal electron acceptor, genes for nitrate ammonification are present. Furthermore, it is the first sequenced genome containing a complete TCA cycle along with the carbon monoxide dehydrogenase pathway. The genome contained a significant percentage of repetitive sequences and transposase-related protein domains enhancing the ability of genome evolution. Likewise, the sulfate reducer N47 genome contained many unique putative genes with unknown function, which are candidates for yet-unknown metabolic pathways.

  16. Proteogenomic Characterization of Monocyclic Aromatic Hydrocarbon Degradation Pathways in the Aniline-Degrading Bacterium Burkholderia sp. K24.

    Directory of Open Access Journals (Sweden)

    Sang-Yeop Lee

    Full Text Available Burkholderia sp. K24, formerly known as Acinetobacter lwoffii K24, is a soil bacterium capable of utilizing aniline as its sole carbon and nitrogen source. Genomic sequence analysis revealed that this bacterium possesses putative gene clusters for biodegradation of various monocyclic aromatic hydrocarbons (MAHs, including benzene, toluene, and xylene (BTX, as well as aniline. We verified the proposed MAH biodegradation pathways by dioxygenase activity assays, RT-PCR, and LC/MS-based quantitative proteomic analyses. This proteogenomic approach revealed four independent degradation pathways, all converging into the citric acid cycle. Aniline and p-hydroxybenzoate degradation pathways converged into the β-ketoadipate pathway. Benzoate and toluene were degraded through the benzoyl-CoA degradation pathway. The xylene isomers, i.e., o-, m-, and p-xylene, were degraded via the extradiol cleavage pathways. Salicylate was degraded through the gentisate degradation pathway. Our results show that Burkholderia sp. K24 possesses versatile biodegradation pathways, which may be employed for efficient bioremediation of aniline and BTX.

  17. Bioremediation of multi-polluted soil by spent mushroom (Agaricus bisporus) substrate: Polycyclic aromatic hydrocarbons degradation and Pb availability.

    Science.gov (United States)

    García-Delgado, Carlos; Yunta, Felipe; Eymar, Enrique

    2015-12-30

    This study investigates the effect of three spent Agaricus bisporus substrate (SAS) application methods on bioremediation of soil multi-polluted with Pb and PAH from close to a shooting range with respect natural attenuation (SM). The remediation treatments involve (i) use of sterilized SAS to biostimulate the inherent soil microbiota (SSAS) and two bioaugmentation possibilities (ii) its use without previous treatment to inoculate A. bisporus and inherent microbiota (SAS) or (iii) SAS sterilization and further A. bisporus re-inoculation (Abisp). The efficiency of each bioremediation microcosm was evaluated by: fungal activity, heterotrophic and PAH-degrading bacterial population, PAH removal, Pb mobility and soil eco-toxicity. Biostimulation of the native soil microbiology (SSAS) achieved similar levels of PAH biodegradation as SM and poor soil detoxification. Bioaugmented microcosms produced higher PAH removal and eco-toxicity reduction via different routes. SAS increased the PAH-degrading bacterial population, but lowered fungal activity. Abisp was a good inoculum carrier for A. bisporus exhibiting high levels of ligninolytic activity, the total and PAH-degrading bacteria population increased with incubation time. The three SAS applications produced slight Pb mobilization (bisporus re-inoculation (Abisp) proved the best application method to remove PAH, mainly BaP, and detoxify the multi-polluted soil.

  18. BIODEGRADATION OF AROMATIC COMPOUNDS UNDER MIXED OXYGEN/DENITRIFYING CONDITIONS: A REVIEW

    Science.gov (United States)

    Bioremediation of aromatic hydrocarbons in groundwater and sediments is often limited by dissolved oxygen. Many aromatic hydrocarbons degrade very slowly or not at all under anaerobic conditions. Nitrate is a good alternative electron acceptor to oxygen, and denitrifying bacteria...

  19. Considering the Specific Impact of Harsh Conditions and Oil Weathering on Diversity, Adaptation, and Activity of Hydrocarbon-Degrading Bacteria in Strategies of Bioremediation of Harsh Oily-Polluted Soils

    Science.gov (United States)

    Al Disi, Zulfa; Jaoua, Samir; Al-Thani, Dhabia; Al-Meer, Saeed

    2017-01-01

    Weathering processes change properties and composition of spilled oil, representing the main reason of failure of bioaugmentation strategies. Our purpose was to investigate the metabolic adaptation of hydrocarbon-degrading bacteria at harsh conditions to be considered to overcome the limitations of bioaugmentation strategies at harsh conditions. Polluted soils, exposed for prolonged periods to weathered oil in harsh soils and weather conditions, were used. Two types of enrichment cultures were employed using 5% and 10% oil or diesel as sole carbon sources with varying the mineral nitrogen sources and C/N ratios. The most effective isolates were obtained based on growth, tolerance to toxicity, and removal efficiency of diesel hydrocarbons. Activities of the newly isolated bacteria, in relation to the microenvironment from where they were isoalted and their interaction with the weathered oil, showed individual specific ability to adapt when exposed to such factors, to acquire metabolic potentialities. Among 39 isolates, ten identified ones by 16S rDNA genes similarities, including special two Pseudomonas isolates and one Citrobacter isolate, showed particularity of shifting hydrocarbon-degrading ability from short chain n-alkanes (n-C12–n-C16) to longer chain n-alkanes (n-C21–n-C25) and vice versa by alternating nitrogen source compositions and C/N ratios. This is shown for the first time. PMID:28243605

  20. Considering the Specific Impact of Harsh Conditions and Oil Weathering on Diversity, Adaptation, and Activity of Hydrocarbon-Degrading Bacteria in Strategies of Bioremediation of Harsh Oily-Polluted Soils

    Directory of Open Access Journals (Sweden)

    Zulfa Al Disi

    2017-01-01

    Full Text Available Weathering processes change properties and composition of spilled oil, representing the main reason of failure of bioaugmentation strategies. Our purpose was to investigate the metabolic adaptation of hydrocarbon-degrading bacteria at harsh conditions to be considered to overcome the limitations of bioaugmentation strategies at harsh conditions. Polluted soils, exposed for prolonged periods to weathered oil in harsh soils and weather conditions, were used. Two types of enrichment cultures were employed using 5% and 10% oil or diesel as sole carbon sources with varying the mineral nitrogen sources and C/N ratios. The most effective isolates were obtained based on growth, tolerance to toxicity, and removal efficiency of diesel hydrocarbons. Activities of the newly isolated bacteria, in relation to the microenvironment from where they were isoalted and their interaction with the weathered oil, showed individual specific ability to adapt when exposed to such factors, to acquire metabolic potentialities. Among 39 isolates, ten identified ones by 16S rDNA genes similarities, including special two Pseudomonas isolates and one Citrobacter isolate, showed particularity of shifting hydrocarbon-degrading ability from short chain n-alkanes (n-C12–n-C16 to longer chain n-alkanes (n-C21–n-C25 and vice versa by alternating nitrogen source compositions and C/N ratios. This is shown for the first time.

  1. Comparative Genomics of the Ubiquitous, Hydrocarbon-degrading Genus Marinobacter

    Science.gov (United States)

    Singer, E.; Webb, E.; Edwards, K. J.

    2012-12-01

    The genus Marinobacter is amongst the most ubiquitous in the global oceans and strains have been isolated from a wide variety of marine environments, including offshore oil-well heads, coastal thermal springs, Antarctic sea water, saline soils and associations with diatoms and dinoflagellates. Many strains have been recognized to be important hydrocarbon degraders in various marine habitats presenting sometimes extreme pH or salinity conditions. Analysis of the genome of M. aquaeolei revealed enormous adaptation versatility with an assortment of strategies for carbon and energy acquisition, sensation, and defense. In an effort to elucidate the ecological and biogeochemical significance of the Marinobacters, seven Marinobacter strains from diverse environments were included in a comparative genomics study. Genomes were screened for metabolic and adaptation potential to elucidate the strategies responsible for the omnipresence of the Marinobacter genus and their remedial action potential in hydrocarbon-polluted waters. The core genome predominantly encodes for key genes involved in hydrocarbon degradation, biofilm-relevant processes, including utilization of external DNA, halotolerance, as well as defense mechanisms against heavy metals, antibiotics, and toxins. All Marinobacter strains were observed to degrade a wide spectrum of hydrocarbon species, including aliphatic, polycyclic aromatic as well as acyclic isoprenoid compounds. Various genes predicted to facilitate hydrocarbon degradation, e.g. alkane 1-monooxygenase, appear to have originated from lateral gene transfer as they are located on gene clusters of 10-20% lower GC-content compared to genome averages and are flanked by transposases. Top ortholog hits are found in other hydrocarbon degrading organisms, e.g. Alcanivorax borkumensis. Strategies for hydrocarbon uptake encoded by various Marinobacter strains include cell surface hydrophobicity adaptation via capsular polysaccharide biosynthesis and attachment

  2. Genome Sequence of Polycyclovorans algicola Strain TG408, an Obligate Polycyclic Aromatic Hydrocarbon-Degrading Bacterium Associated with Marine Eukaryotic Phytoplankton.

    Science.gov (United States)

    Gutierrez, Tony; Thompson, Haydn F; Angelova, Angelina; Whitman, William B; Huntemann, Marcel; Copeland, Alex; Chen, Amy; Kyrpides, Nikos; Markowitz, Victor; Palaniappan, Krishnaveni; Ivanova, Natalia; Mikhailova, Natalia; Ovchinnikova, Galina; Andersen, Evan; Pati, Amrita; Stamatis, Dimitrios; Reddy, T B K; Ngan, Chew Yee; Chovatia, Mansi; Daum, Chris; Shapiro, Nicole; Cantor, Michael N; Woyke, Tanja

    2015-03-26

    Polycyclovorans algicola strain TG408 is a recently discovered bacterium associated with marine eukaryotic phytoplankton and exhibits the ability to utilize polycyclic aromatic hydrocarbons (PAHs) almost exclusively as sole sources of carbon and energy. Here, we present the genome sequence of this strain, which is 3,653,213 bp, with 3,477 genes and an average G+C content of 63.8%.

  3. Genome Sequence of Porticoccus hydrocarbonoclasticus Strain MCTG13d, an Obligate Polycyclic Aromatic Hydrocarbon-Degrading Bacterium Associated with Marine Eukaryotic Phytoplankton.

    Science.gov (United States)

    Gutierrez, Tony; Whitman, William B; Huntemann, Marcel; Copeland, Alex; Chen, Amy; Kyrpides, Nikos; Markowitz, Victor; Pillay, Manoj; Ivanova, Natalia; Mikhailova, Natalia; Ovchinnikova, Galina; Andersen, Evan; Pati, Amrita; Stamatis, Dimitrios; Reddy, T B K; Ngan, Chew Yee; Chovatia, Mansi; Daum, Chris; Shapiro, Nicole; Cantor, Michael N; Woyke, Tanja

    2015-06-18

    Porticoccus hydrocarbonoclasticus strain MCTG13d is a recently discovered bacterium that is associated with marine eukaryotic phytoplankton and that almost exclusively utilizes polycyclic aromatic hydrocarbons (PAHs) as the sole source of carbon and energy. Here, we present the genome sequence of this strain, which is 2,474,654 bp with 2,385 genes and has an average G+C content of 53.1%.

  4. Effect of Sphingobium yanoikuyae B1 inoculation on bacterial community dynamics and polycyclic aromatic hydrocarbon degradation in aged and freshly PAH-contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Cunliffe, Michael [Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT (United Kingdom); Kertesz, Michael A. [Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT (United Kingdom)]. E-mail: michael.kertesz@manchester.ac.uk

    2006-11-15

    Sphingobium yanoikuyae B1 is able to degrade a range of polycyclic aromatic hydrocarbons (PAHs) and as a sphingomonad belongs to one of the dominant genera found in PAH-contaminated soils. We examined the ecological effect that soil inoculation with S. yanoikuyae B1 has on the native bacterial community in three different soils: aged PAH-contaminated soil from an industrial site, compost freshly contaminated with PAHs and un-contaminated compost. Survival of S. yanoikuyae B1 was dependent on the presence of PAHs, and the strain was unable to colonize un-contaminated compost. Inoculation with S. yanoikuyae B1 did not cause extensive changes in the native bacterial community of either soil, as assessed by denaturing gel electrophoresis, but its presence led to an increase in the population level of two other species in the aged contaminated soil community and appeared to have an antagonistic affect on several members of the contaminated compost community, indicating niche competition. - Sphingobium yanoikuyae B1 does not cause major changes in the native bacterial community while colonizing PAH-contaminated soils, but some niche competition is evident.

  5. Screening and degrading characteristics and community structure of a high molecular weight polycyclic aromatic hydrocarbon-degrading bacterial consortium from contaminated soil

    Institute of Scientific and Technical Information of China (English)

    Run Sun; Jinghua Jin; Guangdong Sun; Ying Liu; Zhipei Liu

    2010-01-01

    Inoculation with efficient microbes had been proved to be the most important way for the bioremediation of polluted environments.For the treatment of abandoned site of Beijing Coking Chemical Plant contaminated with high level of high-molecular-weight polycyclic aromatic hydrocarbons (HMW-PAHs),a bacterial consortium capable of degrading HMW-PAHs,designated 1-18-1,was enriched and screened from HMW-PAHs contaminated soil.Its degrading ability was analyzed by high performance liquid chromatography (HPLC),and the community structure was investigated by construction and analyses of the 16S rRNA gene clone libraries (A,B and F) at different transfers.The results indicated that 1-18-1 was able to utilize pyrene,fluoranthene and benzo[a]pyrene as sole carbon and energy source for growth.The degradation rate of pyrene and fluoranthene reached 82.8% and 96.2% after incubation for 8 days at 30℃,respectively;while the degradation rate of benzo[a]pyrene was only 65.1% after incubation for 28 days at 30℃.Totally,108,100 and 100 valid clones were randomly selected and sequenced from the libraries A,B,and E Phylogenetic analyses showed that all the clones could be divided into 5 groups,Bacteroidetes,α-Proteobacteria,Actinobacteria,β-Proteobacteria and γ-Proteobacteria.Sequence similarity analyses showed total 39 operational taxonomic units (OTUs) in the libraries.The predominant bacterial groups were α-Proteobacteria (19 OTUs,48.7%),γ-Proteobacteria (9 OTUs,23.1%) and β-Protcobacteria (8 OTUs,20.5%).During the transfer process,the proportions of α-Proteobacteria and β-Proteobacteria increased greatly (from 47% to 93%),while γ-Proteobacteria decreased from 32% (library A) to 6% (library F);and Bacteroidetes group disappeared in libraries B and F.

  6. Biostimulation Reveals Functional Redundancy of Anthracene-Degrading Bacteria in Polycyclic Aromatic Hydrocarbon-Contaminated Soil.

    Science.gov (United States)

    Dunlevy, Sage R; Singleton, David R; Aitken, Michael D

    2013-11-01

    Stable-isotope probing was previously used to identify bacterial anthracene-degraders in untreated soil from a former manufactured gas plant site. However, subsequent pyrosequence analyses of total bacterial communities and quantification of 16S rRNA genes indicated that relative abundances of the predominant anthracene-degrading bacteria (designated Anthracene Group 1) diminished as a result of biological treatment conditions in lab-scale, aerobic bioreactors. This study identified Alphaproteobacterial anthracene-degrading bacteria in bioreactor-treated soil which were dissimilar to those previously identified. The largest group of sequences was from the Alterythrobacter genus while other groups of sequences were associated with bacteria within the order Rhizobiales and the genus Bradyrhizobium. Conditions in the bioreactor enriched for organisms capable of degrading anthracene which were not the same as those identified as dominant degraders in the untreated soil. Further, these data suggest that identification of polycyclic aromatic hydrocarbon-degrading bacteria in contaminated but untreated soil may be a poor indicator of the most active degraders during biological treatment.

  7. Life in oil :Hydrocarbon-degrading bacterial mineralization in oil spill-polluted marine environment

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The biodegradation of hydrocarbons by microorganisms is one of the primary ways by which an oil spill is eliminated from contaminated sites.One such spill was that of the Russian tanker the Nakhodka that spilled heavy oil into the Sea of Japan on January 2,1997.This paper describes the three main processes of the Nakhodka oil spill,including:(1) the weathering of hydrocarbon-degrading bacteria (genus Pseudomonas)and crystallized organic compounds from the Nakhodka oil spill-polluted seashores after nine years;(2) the laboratory-scale biodegradation of the Nakhodka oil spill over a 429-day period;and (3) the bioavailability of kaolinite clay minerals and the role they play in seawater polluted with the Nakhodka oil spill.Upon the slow evaporation of the Nakhodka oil spill during the 9-year weathering,the dendritic crystal growth of paraffin (a mixture of alkanes) occurred in the oil crust under natural conditions.Heavy metals were obtained in the original heavy oil samples of three seashores in the Sea of Japan.Si,S,Ti,Cr,Ni,Cu,and Zn were found in the original Nakhodka oil spill samples whereas these heavy metals and S were no longer present after 9 years.The anaerobic reverse side of the oil crust contained numerous coccus-type bacteria associated with halite.The hydrocarbon-degrading bacteria and paraffin wax in the oil crust may have a significant effect on the weathering processes of the Nakhodka oil spill during the 9-year bioremediation.A biodegradation process of heavy oil from the Nakhodka oil spill by indigenous microbial consortia was monitored over 429 days in the laboratory.The indigenous microbial consortia consisted of bacteria and fungi as well as the bacterium Pseudomonas aeruginosa isolated from Atake seashore,Ishikawa Prefecture,Japan.Both bacteria and fungi had a significant role in the observed biodegradation of heavy oil during the 429-day bioremediation with respect to the pH of the solution.Hydrocarbon-degrading bacteria had a tendency to

  8. Hydrocarbon-degradation by Isolate Pseudomonas lundensis UTAR FPE2

    Directory of Open Access Journals (Sweden)

    Adeline, S. Y. Ting

    2009-01-01

    Full Text Available In this study, the potential of isolate Pseudomonas lundensis UTAR FPE2 as a hydrocarbon degrader was established. Their biodegradation activity was first detected with the formation of clearing zones on Bushnell-Hass agar plates, with the largest diameter observed on plates supplemented with paraffin, followed by mineral oil and petrol. Utilization of hydrocarbon sources were again detected in broth cultures supplemented with similar hydrocarbon substrates, where the mean viable cell count recovered from hydrocarbon-supplemented broth cultures were higher than the initial inoculum except for napthalene. In both tests, the isolate showed higher degradability towards aliphatic hydrocarbon sources, and the least activity towards the aromatic hydrocarbon naphthalene. The isolate P. lundensis UTAR FPE2 (8 log10 cfu/mL also degraded crude diesel sample, with 69% degradation during the first three days. To conclude, this study suggests the potential use of this isolate for bioremediation of hydrocarbon-contaminated environments.

  9. Candidates for the development of consortia capable of petroleum hydrocarbon degradation in marine environment

    Digital Repository Service at National Institute of Oceanography (India)

    David, J.; Gupta, R.; Mohandass, C.; Nair, S.; LokaBharathi, P.A.; Chandramohan, D.

    Bacteria and yeasts from different niches of the tropical Indian waters were screened for their hydrocarbon degrading potential using 1% w/v in artificial seawater over a period of 6 days. About 20% of the 75 bacterial and 24% of the 27 yeast...

  10. 盐碱土壤多环芳烃降解菌群筛选及其降解特性%Screening and Biodegradation Characteristics of Polycyclic Aromatic Hydrocarbons-Degrading Consortium From Saline-Alkali Soil

    Institute of Scientific and Technical Information of China (English)

    宋立超; 刘灵芝; 李培军; 刘宛; 张玉龙

    2012-01-01

    为了强化多环芳烃(PAHs)污染盐碱土壤原位微生物修复的应用,并提供高效的菌种资源,从天津大港油田盐碱化的油污土壤中富集分离出1组高效降解菲、芘的耐盐碱菌群,分离获得可培养优势细菌5株、真菌3株,考察了该菌群对菲、芘的降解效果,并进行了其对菲、芘降解特性分析.结果表明,该菌群在菲、芘质量浓度分别为25、50和75 mg/L的液体无机盐培养基中培养15 d,菲、芘的降解率分别达到75.3%和53.6%、56.6%和52.0%、25.2%和13.6%;该菌群对菲、芘降解具有较广泛的盐质量分数和pH值范围,在菲、芘初始质量浓度各为50 mg/L,最适盐质量分数0~2%,最适pH值8.6条件下,添加质量分数0.4%葡萄糖培养15d后,菲、芘的降解率显著提高,达到92.1%和65.8%.细菌16S rDNA和真菌18S rDNA测序结果表明,该菌群由叶杆菌属(Phyllobacterium)、假单胞菌属(Pseudomonas)、盐单胞属(Halomonas)、泛菌属(Pantoea)和青霉属(Penicillium)、双曲孢属(Sigmoidea)、胶孢炭疽属(Colletotrichum)组成.%The salt and alkaline endurable microbial consortium of degrading phenanthrene and pyrene effectively was developed from oil-contaminated saline-alkali soil of Tianjin Dagang oil field to intensify the application of situ bioremediation of polycyclic aromatic hydrocarbons in saline-alkaline soil and to provide highly effective microorganisms resources. Five cultivable dominate bacterium strains and three fungi strains through separation were obtained, and their degradation characteristics for phenanthrene and pyrene were analyzed. The degradation rates of phenanthrene and pyrene with 25, 50 and 75 mg/L initial concentration by the microbial consortium in liquid mineral medium after 15 d cultivation were 75. 3% and 53. 6%, 56. 6% and 52. 0%, 25. 2% and 13.6% respectively, meanwhile, when the initial concentration of phenanthrene and pyrene was 50 mg/L, respectively, the most

  11. Bioremediation of hydrocarbon degradation in a petroleum-contaminated soil and microbial population and activity determination.

    Science.gov (United States)

    Wu, Manli; Li, Wei; Dick, Warren A; Ye, Xiqiong; Chen, Kaili; Kost, David; Chen, Liming

    2017-02-01

    Bioremediation of hydrocarbon degradation in petroleum-polluted soil is carried out by various microorganisms. However, little information is available for the relationships between hydrocarbon degradation rates in petroleum-contaminated soil and microbial population and activity in laboratory assay. In a microcosm study, degradation rate and efficiency of total petroleum hydrocarbons (TPH), alkanes, and polycyclic aromatic hydrocarbons (PAH) in a petroleum-contaminated soil were determined using an infrared photometer oil content analyzer and a gas chromatography mass spectrometry (GC-MS). Also, the populations of TPH, alkane, and PAH degraders were enumerated by a modified most probable number (MPN) procedure, and the hydrocarbon degrading activities of these degraders were determined by the Biolog (MT2) MicroPlates assay. Results showed linear correlations between the TPH and alkane degradation rates and the population and activity increases of TPH and alkane degraders, but no correlation was observed between the PAH degradation rates and the PAH population and activity increases. Petroleum hydrocarbon degrading microbial population measured by MPN was significantly correlated with metabolic activity in the Biolog assay. The results suggest that the MPN procedure and the Biolog assay are efficient methods for assessing the rates of TPH and alkane, but not PAH, bioremediation in oil-contaminated soil in laboratory.

  12. Generalist hydrocarbon-degrading bacterial communities in the oil-polluted water column of the North Sea

    NARCIS (Netherlands)

    Chronopoulou, P.M.; Sanni, G.O.; Silas-Olu, D.I.; van der Meer, J.R.; Timmis, K.N.; Brussaard, C.P.D.; McGenity, T.J.

    2015-01-01

    The aim of this work was to determine the effect of light crude oil on bacterial communities during an experimental oil spill in the North Sea and in mesocosms (simulating a heavy, enclosed oil spill), and to isolate and characterize hydrocarbon-degrading bacteria from the water column. No oil-induc

  13. Separation of Petroleum Hydrocarbon Degrading Bacteria and its Application in Oily Sludge%石油烃降解菌的分离及在含油污泥中的应用

    Institute of Scientific and Technical Information of China (English)

    姚力芬; 李丹; 陈丽华; 李广彬; 孙盼盼; 李佳酿

    2015-01-01

    文章从甘肃陇东长庆油田污染严重的土壤中分离筛选得到六株石油烃降解菌,分别命名为a1、a2、a3、a4、a5和a6,对它们进行了常规鉴定,得到a1、a2、a3均为芽孢杆菌,a4、a6均为假单胞菌,a5为不动杆菌.通过菌剂的复活、发酵得到降解石油烃复合菌,并进行了微生物修复含油污泥的小试实验.结果表明,当土壤中的石油含量为50g/kg时,加入混合菌剂的石油降解率比没有加菌剂的降解效率高,添加4%菌剂后81d的降解率为90.20%,大于对照组(只添加有机肥)的降解率31.10%,说明该混合菌剂具有应用于实际石油污染土壤生物修复的潜力.%The isolation of six strains of petroleum degrading bacteria from contaminated Gansu Longdong Changqing Oilfield serious soil, which were named as A1, A2, A3, A4, A5 and A6 were carried out routine identification, A1, A2 and A3 were bacillus, A4, A6 were Pseudomonas A5, acinetobacter. Get the degradation of petroleum hydrocarbon compound bacteria through fermentation, resurrection, and carried out experiments of microbial remediation of oily sludge. The results show that when the oil content in soil was 50g/kg, adding oil degrading mixed inoculum rate than the degradation efficiency without inoculum, adding 4% agent 81D degradation rate was 90.20% higher than that of control group (add organic fertilizer) the degradation rate of 31.10%, indicating that the mixed bacteria agent is applied to the actual oil the potential for bioremediation of contaminated soil.

  14. Comparison of Paraffin and Diesel Oil as Cultivation Medium Supplements for Preparing a Hydrocarbon-Degrading Bacterial Biomass

    Directory of Open Access Journals (Sweden)

    Dokukins Eduards

    2016-05-01

    Full Text Available The effect of liquid paraffin and diesel oil as nutrient amendments for hydrocarbon-degrading bacteria was compared. Different parameters were analyzed - optical density of bacterial suspension, oxygen consumption by biomass, morphology of bacteria, etc. In some experiments the paraffin was more preferable for microorganisms, but in other tests the results for both substances were similar. The influence of the comparable substances strongly depends on cultivation conditions.

  15. Mutagenesis of a Hydrocarbon Degrading and Biosurfactants-Producing Bacteria with Low Energy Ions%低能离子诱变产表面活性剂的烃降解菌研究

    Institute of Scientific and Technical Information of China (English)

    向廷生; 马飞; 张祥胜

    2012-01-01

    为有效治理石油污染土壤,从长期遭受石油污染的土壤中筛选出一株烃降解菌8-11作为出发菌,利用低能N+注入烃降解菌进行诱变,在能量为20 keV、剂量为90×2.6×1013 ions/cm2条件下筛选出一株高效烃降解菌——诱变菌23.原油摇瓶发酵实验表明诱变菌对原油的降解率达到74%;降解后原油的全烃气相色谱图显示,经过7d的作用,原油中的正构烷烃完全降解.诱变菌23能够产生大量的生物表面活性物质,傅里叶红外光谱分析表明其产生的生物活性物质为糖脂类化合物,该糖脂类生物表面活性剂能使发酵液的表面张力从空白对照的56.1 mN/m降低为29.3 mN/m.研究表明诱变菌23具有较高的烃降解能力,能有效降低表面张力,具有较大的应用潜力.%To remediate petroleum-contaminated soil effectively, bacteria 8-11, isolated from oil contaminated soil in Daqing Oilfield, was implanted with low energy N+(90×2.6×l013 ions/cm2 and 20 keV), and finally the strain of mutant 23 which could efficiently degrade oil was obtained. The degradation of petroleum hydrocarbon by mutant 23 was investigated, and results indicated that the biodegradation rate of total petroleum hydrocarbon (TPH) reached 74% after 7d treatment, and n-alkane of oil composition was degraded completely. Biosurfactants, which produced by mutant 23 and mainly indentified as glycolipid by FT-IR analysis, could reduce the surface tension of culture from 56.1 mN/m (CK) to 29.3 mN/m. Characteristics of bacterial mutant 23 suggested its potential application in bioremediation of petroleum-contaminated soil.

  16. Hydrocarbon degradation, plant colonization and gene expression of alkane degradation genes by endophytic Enterobacter ludwigii strains

    Energy Technology Data Exchange (ETDEWEB)

    Yousaf, Sohail [AIT Austrian Institute of Technology GmbH, Bioresources Unit, A-2444 Seibersdorf (Austria); Afzal, Muhammad [AIT Austrian Institute of Technology GmbH, Bioresources Unit, A-2444 Seibersdorf (Austria); National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad (Pakistan); Reichenauer, Thomas G. [AIT Austrian Institute of Technology GmbH, Environmental Resources and Technologies Unit, A-2444 Seibersdorf (Austria); Brady, Carrie L. [Forestry and Agricultural Biotechnology Institute, Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria (South Africa); Sessitsch, Angela, E-mail: angela.sessitsch@ait.ac.at [AIT Austrian Institute of Technology GmbH, Bioresources Unit, A-2444 Seibersdorf (Austria)

    2011-10-15

    The genus Enterobacter comprises a range of beneficial plant-associated bacteria showing plant growth promotion. Enterobacter ludwigii belongs to the Enterobacter cloacae complex and has been reported to include human pathogens but also plant-associated strains with plant beneficial capacities. To assess the role of Enterobacter endophytes in hydrocarbon degradation, plant colonization, abundance and expression of CYP153 genes in different plant compartments, three plant species (Italian ryegrass, birdsfoot trefoil and alfalfa) were grown in sterile soil spiked with 1% diesel and inoculated with three endophytic E. ludwigii strains. Results showed that all strains were capable of hydrocarbon degradation and efficiently colonized the rhizosphere and plant interior. Two strains, ISI10-3 and BRI10-9, showed highest degradation rates of diesel fuel up to 68% and performed best in combination with Italian ryegrass and alfalfa. All strains expressed the CYP153 gene in all plant compartments, indicating an active role in degradation of diesel in association with plants. - Highlights: > E. ludwigii strains efficiently colonized plants in a non-sterile soil environment. > E. ludwigii strains efficiently expressed alkane degradation genes in plants. > E. ludwigii efficiently degraded alkane contaminations and promoted plant growth. > E. ludwigii interacted more effectively with Italian ryegrass than with other plants. > Degradation activity varied with plant and microbial genotype as well as with time. - Enterobacter ludwigii strains belonging to the E. cloacae complex are able to efficiently degrade alkanes when associated with plants and to promote plant growth.

  17. Isolation and Characterization of Hydrocarbon-Degrading Yeast Strains from Petroleum Contaminated Industrial Wastewater.

    Science.gov (United States)

    Gargouri, Boutheina; Mhiri, Najla; Karray, Fatma; Aloui, Fathi; Sayadi, Sami

    2015-01-01

    Two yeast strains are enriched and isolated from industrial refinery wastewater. These strains were observed for their ability to utilize several classes of petroleum hydrocarbons substrates, such as n-alkanes and aromatic hydrocarbons as a sole carbon source. Phylogenetic analysis based on the D1/D2 variable domain and the ITS-region sequences indicated that strains HC1 and HC4 were members of the genera Candida and Trichosporon, respectively. The mechanism of hydrocarbon uptaking by yeast, Candida, and Trichosporon has been studied by means of the kinetic analysis of hydrocarbons-degrading yeasts growth and substrate assimilation. Biodegradation capacity and biomass quantity were daily measured during twelve days by gravimetric analysis and gas chromatography coupled with mass spectrometry techniques. Removal of n-alkanes indicated a strong ability of hydrocarbon biodegradation by the isolated yeast strains. These two strains grew on long-chain n-alkane, diesel oil, and crude oil but failed to grow on short-chain n-alkane and aromatic hydrocarbons. Growth measurement attributes of the isolates, using n-hexadecane, diesel oil, and crude oil as substrates, showed that strain HC1 had better degradation for hydrocarbon substrates than strain HC4. In conclusion, these yeast strains can be useful for the bioremediation process and decreasing petroleum pollution in wastewater contaminated with petroleum hydrocarbons.

  18. Isolation and Characterization of Hydrocarbon-Degrading Yeast Strains from Petroleum Contaminated Industrial Wastewater

    Directory of Open Access Journals (Sweden)

    Boutheina Gargouri

    2015-01-01

    Full Text Available Two yeast strains are enriched and isolated from industrial refinery wastewater. These strains were observed for their ability to utilize several classes of petroleum hydrocarbons substrates, such as n-alkanes and aromatic hydrocarbons as a sole carbon source. Phylogenetic analysis based on the D1/D2 variable domain and the ITS-region sequences indicated that strains HC1 and HC4 were members of the genera Candida and Trichosporon, respectively. The mechanism of hydrocarbon uptaking by yeast, Candida, and Trichosporon has been studied by means of the kinetic analysis of hydrocarbons-degrading yeasts growth and substrate assimilation. Biodegradation capacity and biomass quantity were daily measured during twelve days by gravimetric analysis and gas chromatography coupled with mass spectrometry techniques. Removal of n-alkanes indicated a strong ability of hydrocarbon biodegradation by the isolated yeast strains. These two strains grew on long-chain n-alkane, diesel oil, and crude oil but failed to grow on short-chain n-alkane and aromatic hydrocarbons. Growth measurement attributes of the isolates, using n-hexadecane, diesel oil, and crude oil as substrates, showed that strain HC1 had better degradation for hydrocarbon substrates than strain HC4. In conclusion, these yeast strains can be useful for the bioremediation process and decreasing petroleum pollution in wastewater contaminated with petroleum hydrocarbons.

  19. Microbial Degradation of Polycyclic Aromatic Hydrocarbons and Characterization of Bacteria

    Science.gov (United States)

    Tikilili, P. V.; Chirwa, E. M. N.

    2010-01-01

    Biodegradation of polycyclic aromatic hydrocarbons was studied. Naphthalene was used as a model compound to represent these compounds. Low initial concentrations of naphthalene in a range of 30-60 mg/L were completely degraded after incubation for 15 hrs by consortia from a landfill soil while consortia from minewater took more that 29 hrs to reach complete degradation.

  20. Environmental diagnostic analysis of ground water bacteria and their involvement in utilization of aromatic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Wear, J.E. Jr.

    1993-05-01

    The objective of this study was to examine the hypothesis that select functional groups of bacteria from pristine sites have an innate ability to degrade synthetic aromatics that often contaminate groundwater environments,due to exposure to naturally occurring recalcitrant aromatics in their environment. This study demonstrates that subsurface microbial communities are capable of utilizing lignin and humic acid breakdown products. Utilizers of these compounds were found to be present in most all the wells tested. Even the deepest aquifer tested had utilizers present for all six of the aromatics tested. Highest counts for the aromatics tested were observed with the naturally occurring breakdown products of either lignin or humic acid. Carboxylic acids were found to be an important sole carbon source for groundwater bacteria possibly explained by the fact that they are produced by the oxidative cleavage of aromatic ring structures. The carbohydrate sole carbon sources that demonstrated the greatest densities were ones commonly associated with humics. This study indicates that utilization of naturally occurring aromatic compounds in the subsurface is an important nutritional source for groundwater bacteria. In addition, it suggests that adaptation to naturally occurring recalcitrant substrates is the origin of degradative pathways for xenobiotic compounds with analogous structure. This work has important implications for in situ bioremediation as a method of environmental cleanup.

  1. Comparative analysis of metagenomes from three methanogenic hydrocarbon-degrading enrichment cultures with 41 environmental samples.

    Science.gov (United States)

    Tan, Boonfei; Fowler, S Jane; Abu Laban, Nidal; Dong, Xiaoli; Sensen, Christoph W; Foght, Julia; Gieg, Lisa M

    2015-09-01

    Methanogenic hydrocarbon metabolism is a key process in subsurface oil reservoirs and hydrocarbon-contaminated environments and thus warrants greater understanding to improve current technologies for fossil fuel extraction and bioremediation. In this study, three hydrocarbon-degrading methanogenic cultures established from two geographically distinct environments and incubated with different hydrocarbon substrates (added as single hydrocarbons or as mixtures) were subjected to metagenomic and 16S rRNA gene pyrosequencing to test whether these differences affect the genetic potential and composition of the communities. Enrichment of different putative hydrocarbon-degrading bacteria in each culture appeared to be substrate dependent, though all cultures contained both acetate- and H2-utilizing methanogens. Despite differing hydrocarbon substrates and inoculum sources, all three cultures harbored genes for hydrocarbon activation by fumarate addition (bssA, assA, nmsA) and carboxylation (abcA, ancA), along with those for associated downstream pathways (bbs, bcr, bam), though the cultures incubated with hydrocarbon mixtures contained a broader diversity of fumarate addition genes. A comparative metagenomic analysis of the three cultures showed that they were functionally redundant despite their enrichment backgrounds, sharing multiple features associated with syntrophic hydrocarbon conversion to methane. In addition, a comparative analysis of the culture metagenomes with those of 41 environmental samples (containing varying proportions of methanogens) showed that the three cultures were functionally most similar to each other but distinct from other environments, including hydrocarbon-impacted environments (for example, oil sands tailings ponds and oil-affected marine sediments). This study provides a basis for understanding key functions and environmental selection in methanogenic hydrocarbon-associated communities.

  2. Comparative analysis of metagenomes from three methanogenic hydrocarbon-degrading enrichment cultures with 41 environmental samples

    Science.gov (United States)

    Tan, Boonfei; Jane Fowler, S; Laban, Nidal Abu; Dong, Xiaoli; Sensen, Christoph W; Foght, Julia; Gieg, Lisa M

    2015-01-01

    Methanogenic hydrocarbon metabolism is a key process in subsurface oil reservoirs and hydrocarbon-contaminated environments and thus warrants greater understanding to improve current technologies for fossil fuel extraction and bioremediation. In this study, three hydrocarbon-degrading methanogenic cultures established from two geographically distinct environments and incubated with different hydrocarbon substrates (added as single hydrocarbons or as mixtures) were subjected to metagenomic and 16S rRNA gene pyrosequencing to test whether these differences affect the genetic potential and composition of the communities. Enrichment of different putative hydrocarbon-degrading bacteria in each culture appeared to be substrate dependent, though all cultures contained both acetate- and H2-utilizing methanogens. Despite differing hydrocarbon substrates and inoculum sources, all three cultures harbored genes for hydrocarbon activation by fumarate addition (bssA, assA, nmsA) and carboxylation (abcA, ancA), along with those for associated downstream pathways (bbs, bcr, bam), though the cultures incubated with hydrocarbon mixtures contained a broader diversity of fumarate addition genes. A comparative metagenomic analysis of the three cultures showed that they were functionally redundant despite their enrichment backgrounds, sharing multiple features associated with syntrophic hydrocarbon conversion to methane. In addition, a comparative analysis of the culture metagenomes with those of 41 environmental samples (containing varying proportions of methanogens) showed that the three cultures were functionally most similar to each other but distinct from other environments, including hydrocarbon-impacted environments (for example, oil sands tailings ponds and oil-affected marine sediments). This study provides a basis for understanding key functions and environmental selection in methanogenic hydrocarbon-associated communities. PMID:25734684

  3. Effects of prokaryotic diversity changes on hydrocarbon degradation rates and metal partitioning during bioremediation of contaminated anoxic marine sediments.

    Science.gov (United States)

    Rocchetti, Laura; Beolchini, Francesca; Hallberg, Kevin B; Johnson, D Barrie; Dell'Anno, Antonio

    2012-08-01

    We investigated changes of prokaryotic diversity during bioremediation experiments carried out on anoxic marine sediments characterized by high hydrocarbon and metal content. Microcosms containing contaminated sediments were amended with lactose and acetate and incubated in anaerobic conditions up to 60 d at 20 or 35 °C. Microcosms displaying higher degradation efficiency of hydrocarbons were characterized by the dominance of Alphaproteobacteria and Methanosarcinales and the lack of gene sequences belonging to known hydrocarbonoclastic bacteria. Multivariate analyses support the hypothesis that Alphaproteobacteria are important for hydrocarbon degradation and highlight a potential synergistic effect of archaea and bacteria in changes of metal partitioning. Overall, these results point out that the identification of changes in the prokaryotic diversity during bioremediation of contaminated marine sediments is not only important for the improvement of bio-treatment performance towards hydrocarbons, but also for a better comprehension of changes occurring in metal partitioning which affect their mobility and toxicity.

  4. Advances in the field of high‐molecular‐weight polycyclic aromatic hydrocarbon biodegradation by bacteria

    OpenAIRE

    Kanaly, Robert A.; Harayama, Shigeaki

    2010-01-01

    Summary Interest in understanding prokaryotic biotransformation of high‐molecular‐weight polycyclic aromatic hydrocarbons (HMW PAHs) has continued to grow and the scientific literature shows that studies in this field are originating from research groups from many different locations throughout the world. In the last 10 years, research in regard to HMW PAH biodegradation by bacteria has been further advanced through the documentation of new isolates that represent diverse bacterial types that...

  5. Capacity of Aromatic Compound Degradation by Bacteria from Amazon Dark Earth

    Directory of Open Access Journals (Sweden)

    Fernanda Mancini Nakamura

    2014-06-01

    Full Text Available Amazon dark earth (ADE is known for its high organic matter content, biochar concentration and microbial diversity. The biochar amount suggests the existence of microorganisms capable of degrading aromatic hydrocarbons (AHs. In an effort to investigate the influence of bacteria on the resilience and fertility of these soils, we enriched five ADE soils with naphthalene and phenanthrene, and biodegradation assays with phenanthrene and diesel oil were carried out, as well. After DNA extraction, amplification and sequencing of the 16S rRNA bacterial gene, we identified 148 isolates as the Proteobacteria, Firmicutes and Actinobacteria phyla comprising genera closely related to AHs biodegradation. We obtained 128 isolates that degrade diesel oil and 115 isolates that degrade phenanthrene. Some isolates were successful in degrading both substrates within 2 h. In conclusion, the obtained isolates from ADE have degrading aromatic compound activity, and perhaps, the biochar content has a high influence on this.

  6. Aromatic compound degradation by iron reducing bacteria isolated from irrigated tropical paddy soils

    Institute of Scientific and Technical Information of China (English)

    LU Wenjing; WANG Hongtao; HUANG Changyong; W. Reichardt

    2008-01-01

    Forty-six candidate phenol/benzoate degrading-iron reducing bacteria were isolated from long term irrigated tropical paddy soils by enrichment procedures. Pure cultures and some prepared mixed cultures were examined for ferric oxide reduction and phenol/benzoate degradation. All the isolates were iron reducers, but only 56.5% could couple iron reduction to phenol and/or benzoate degradation, as evidenced by depletion of phenol and benzoate after one week incubation. Analysis of degradative capability using Biolog MT plates revealed that most of them could degrade other aromatic compounds such as ferulic acid, vanillic acid, and hydroxybenzoate. Mixed-cultures and soft samples displayed greater capacity for aromatic degradation and iron reduction than pure bacterial isolates, suggesting that these reactions may be coupled via a consortia-based mechanism in paddy soils.

  7. Degradation of Polycyclic Aromatic Hydrocarbons (PAHs) by Bacteria Isolated from Light Oil Polluted Soils

    Science.gov (United States)

    Ohnuma, T.; Suto, K.; Inoue, C.

    2007-03-01

    Polycyclic aromatic hydrocarbons (PAHs) have polluted soil and groundwater widely and for long term because of their low solubility at normal temperature. Several microorganisms, such as Pseudomonas sp., Sphigomonas sp., a white-rot fungus and so on, being able to decompose PAHs, have been isolated and researched. This study reported to investigate biodegradation of low molecule PAH by isolated bacteria from light oil polluted soil. 12 isolates were obtained from a light oil polluted soil using naphthalene, fluorene and anthracene as sole carbon source, of which 4 isolates grew with naphthalene, 4 isolates did with fluorene and 4 isolates did with anthracene. Among them 3 isolates showed the ability to degrade phenanthrene additionally. These phenanthrene degradation and growth rates were almost same as that of S. yanoikuyae (DSM6900), which is the typical bacteria of PAHs degrader. Therefore, the isolate seemed to have an expectation for PAHs degradation.

  8. Formation of a carcinogenic aromatic amine from an azo dye by human skin bacteria in vitro.

    Science.gov (United States)

    Platzek, T; Lang, C; Grohmann, G; Gi, U S; Baltes, W

    1999-09-01

    Azo dyes represent the major class of dyestuffs. They are metabolised to the corresponding amines by liver enzymes and the intestinal microflora following incorporation by both experimental animals and humans. For safety evaluation of the dermal exposure of consumers to azo dyes from wearing coloured textiles, a possible cleavage of azo dyes by the skin microflora should be considered since, in contrast to many dyes, aromatic amines are easily absorbed by the skin. A method for measuring the ability of human skin flora to reduce azo dyes was established. In a standard experiment, 3x10(11) cells of a culture of Staphylococcus aureus were incubated in synthetic sweat (pH 6.8, final volume 20 mL) at 28 degrees C for 24 h with Direct Blue 14 (C.I. 23850, DB 14). The reaction products were extracted and analysed using HPLC. The reduction product o-tolidine (3,3'-dimethylbenzidine, OT) could indeed be detected showing that the strain used was able to metabolise DB 14 to the corresponding aromatic amine. In addition to OT, two further metabolites of DB 14 were detected. Using mass spectrometry they were identified as 3,3'-dimethyl-4-amino-4'-hydroxybiphenyl and 3, 3'-dimethyl-4-aminobiphenyl. The ability to cleave azo dyes seems to be widely distributed among human skin bacteria, as, under these in vitro conditions, bacteria isolated from healthy human skin and human skin bacteria from strain collections also exhibited azo reductase activity. Further studies are in progress in order to include additional azo dyes and coloured textiles. At the moment, the meaning of the results with regard to consumer health cannot be finally assessed.

  9. Use of the Complex Conductivity Method to Monitor Hydrocarbon Degradation in Brackish Environments

    Science.gov (United States)

    Ntarlagiannis, D.; Beaver, C. L.; Kimak, C.; Slater, L. D.; Atekwana, E. A.; Rossbach, S.

    2015-12-01

    Hydrocarbon contamination of the subsurface is a global environmental problem. The size, location and recurrence rate of contamination very often inhibits active remediation strategies. When there is no direct threat to humans, and direct/invasive remediation methods are prohibited, monitored natural attenuation is often the remediation method of choice. Consequently, long-term monitoring of hydrocarbon degradation is needed to validate remediation. Geophysical methods, frequently utilized to characterize subsurface contamination, have the potential to be adopted for long term monitoring of contaminant degradation. Over the last decade, the complex conductivity method has shown promise as a method for monitoring hydrocarbon degradation processes in freshwater environments. We investigated the sensitivity of complex conductivity to natural attenuation of oil in a brackish setting, being more representative of the conditions where most oil spills occur such as in coastal environments. We performed a series of laboratory hydrocarbon biodegradation experiments whilst continuously monitoring complex conductivity. Sediments from a beach impacted by the Deepwater Horizon (DWH) spill were used to provide the hydrocarbon degraders, while fluids with three different salinities, ranging from fresh water to brackish water, were used as the supporting media. All experimental columns, including two abiotic controls, were run in duplicate. Early results show a dependence of the complex conductivity parameters (both electrolytic and interfacial) on biodegradation processes. Despite the small signals relative to freshwater conditions, the imaginary part of the complex conductivity appears to be sensitive to biodegradation processes. The columns with highest salinity fluids - similar to the salinites for the site where the sediments were collected - showed distinctive complex conductivity responses similar to microbial growth curves. Geochemical monitoring confirmed elevated rates

  10. Polycyclic aromatic hydrocarbon degradation by the white rot fungus Bjerkandera sp. strain BOS55.

    NARCIS (Netherlands)

    Kotterman, M.J.J.

    1998-01-01

    Outline of this thesisIn this thesis the conditions for optimal PAH oxidation by the white rot fungus Bjerkandera sp. strain BOS55 were evaluated. In Chapter 2, culture conditions like aeration and cosubstrate concentrations, which influenced the oxidation of the PAH compound anthra

  11. Functional genes to assess nitrogen cycling and aromatic hydrocarbon degradation: primers and processing matter

    Directory of Open Access Journals (Sweden)

    Christopher Ryan Penton

    2013-09-01

    Full Text Available Targeting sequencing to genes involved in key environmental processes, i.e. ecofunctional genes, provides an opportunity to sample nature’s gene guilds to greater depth and help link community structure to process-level outcomes. Vastly different approaches have been implemented for sequence processing and, ultimately, for taxonomic placement of these gene reads. The overall quality of next generation sequence analysis of functional genes is dependent on multiple steps and assumptions of unknown diversity. To illustrate current issues surrounding amplicon read processing we provide examples for three ecofunctional gene groups. A combination of in-silico, environmental and cultured strain sequences was used to test new primers targeting the dioxin and dibenzofuran degrading genes dxnA1, dbfA1, and carAa. The majority of obtained environmental sequences were classified into novel sequence clusters, illustrating the discovery value of the approach. For the nitrite reductase step in denitrification, the well-known nirK primers exhibited deficiencies in reference database coverage, illustrating the need to refine primer-binding sites and/or to design multiple primers, while nirS primers exhibited bias against five phyla. Amino acid-based OTU clustering of these two N-cycle genes from soil samples yielded only 114 unique nirK and 45 unique nirS genus-level groupings, likely a reflection of constricted primer coverage. Finally, supervised and non-supervised OTU analysis methods were compared using the nifH gene of nitrogen fixation, with generally similar outcomes, but the clustering (non-supervised method yielded higher diversity estimates and stronger site-based differences. High throughput amplicon sequencing can provide inexpensive and rapid access to nature’s related sequences by circumventing the culturing barrier, but each unique gene requires individual considerations in terms of primer design and sequence processing and classification.

  12. The hydrocarbon-degrading marine bacterium Cobetia sp. strain MM1IDA2H-1 produces a biosurfactant that interferes with quorum sensing of fish pathogens by signal hijacking.

    Science.gov (United States)

    Ibacache-Quiroga, C; Ojeda, J; Espinoza-Vergara, G; Olivero, P; Cuellar, M; Dinamarca, M A

    2013-07-01

    Biosurfactants are produced by hydrocarbon-degrading marine bacteria in response to the presence of water-insoluble hydrocarbons. This is believed to facilitate the uptake of hydrocarbons by bacteria. However, these diffusible amphiphilic surface-active molecules are involved in several other biological functions such as microbial competition and intra- or inter-species communication. We report the isolation and characterization of a marine bacterial strain identified as Cobetia sp. MM1IDA2H-1, which can grow using the sulfur-containing heterocyclic aromatic hydrocarbon dibenzothiophene (DBT). As with DBT, when the isolated strain is grown in the presence of a microbial competitor, it produces a biosurfactant. Because the obtained biosurfactant was formed by hydroxy fatty acids and extracellular lipidic structures were observed during bacterial growth, we investigated whether the biosurfactant at its critical micelle concentration can interfere with bacterial communication systems such as quorum sensing. We focused on Aeromonas salmonicida subsp. salmonicida, a fish pathogen whose virulence relies on quorum sensing signals. Using biosensors for quorum sensing based on Chromobacterium violaceum and Vibrio anguillarum, we showed that when the purified biosurfactant was mixed with N-acyl homoserine lactones produced by A. salmonicida, quorum sensing was inhibited, although bacterial growth was not affected. In addition, the transcriptional activities of A. salmonicida virulence genes that are controlled by quorum sensing were repressed by both the purified biosurfactant and the growth in the presence of Cobetia sp. MM1IDA2H-1. We propose that the biosurfactant, or the lipid structures interact with the N-acyl homoserine lactones, inhibiting their function. This could be used as a strategy to interfere with the quorum sensing systems of bacterial fish pathogens, which represents an attractive alternative to classical antimicrobial therapies in fish aquaculture.

  13. Antimicrobial activity of essential oils from Mediterranean aromatic plants against several foodborne and spoilage bacteria.

    Science.gov (United States)

    Silva, Nuno; Alves, Sofia; Gonçalves, Alexandre; Amaral, Joana S; Poeta, Patrícia

    2013-12-01

    The antimicrobial activity of essential oils extracted from a variety of aromatic plants, often used in the Portuguese gastronomy was studied in vitro by the agar diffusion method. The essential oils of thyme, oregano, rosemary, verbena, basil, peppermint, pennyroyal and mint were tested against Gram-positive (Listeria monocytogenes, Clostridium perfringens, Bacillus cereus, Staphylococcus aureus, Enterococcus faecium, Enterococcus faecalis, and Staphylococcus epidermidis) and Gram-negative strains (Salmonella enterica, Escherichia coli, and Pseudomonas aeruginosa). For most essential oils examined, S. aureus, was the most susceptible bacteria, while P. aeruginosa showed, in general, least susceptibility. Among the eight essential oils evaluated, thyme, oregano and pennyroyal oils showed the greatest antimicrobial activity, followed by rosemary, peppermint and verbena, while basil and mint showed the weakest antimicrobial activity. Most of the essential oils considered in this study exhibited a significant inhibitory effect. Thyme oil showed a promising inhibitory activity even at low concentration, thus revealing its potential as a natural preservative in food products against several causal agents of foodborne diseases and food spoilage. In general, the results demonstrate that, besides flavoring the food, the use of aromatic herbs in gastronomy can also contribute to a bacteriostatic effect against pathogens.

  14. Degradation of Polycyclic Aromatic Hydrocarbon Pyrene by Biosurfactant-Producing Bacteria Gordonia cholesterolivorans AMP 10

    Directory of Open Access Journals (Sweden)

    Tri Handayani Kurniati

    2016-12-01

    Full Text Available Pyrene degradation and biosurfactant activity by a new strain identified as Gordonia cholesterolivorans AMP 10 were studied. The strain grew well and produced effective biosurfactants in the presence of glucose, sucrose, and crude oil. The biosurfactants production was detected by the decreased surface tension of the medium and emulsification activity.  Analysis of microbial growth parameters showed that AMP10 grew best at 50 µg mL-1 pyrene concentration, leading to 96 % degradation of pyrene within 7 days. The result of nested PCR analysis revealed that this isolate possessed the nahAc gene which encodes dioxygenase enzyme for initial degradation of Polycyclic Aromatic Hydrocarbon (PAH. Observation of both tensio-active and emulsifying activities indicated that biosurfactants which produced by AMP 10 when grown on glucose could lower the surface tension of medium from 71.3 mN/m to 24.7 mN/m and formed a stable emulsion in used lubricant oil with an emulsification index (E24 of 74%. According to the results, it is suggested that the bacterial isolates G. cholesterolivorans AMP10 are suitable candidates for bioremediation of PAH-contaminated environments.How to CiteKurniati, T. H.,  Rusmana, I. Suryani, A. & Mubarik, N. R. (2016. Degradation of Polycyclic Aromatic Hydrocarbon Pyrene by Biosurfactant-Producing Bacteria Gordonia cholesterolivorans AMP 10. Biosaintifika: Journal of Biology & Biology Education, 8(3, 336-343. 

  15. Biodegradation potential of polycyclic aromatic hydrocarbons by bacteria strains enriched from Yangtze River sediments.

    Science.gov (United States)

    Xu, Xiaoyi; Chen, Xi; Su, Pan; Fang, Fang; Hu, Bibo

    2016-01-01

    Microbial degradation is an effective method for the removal of polycyclic aromatic hydrocarbons (PAHs) compounds from polluted sediments. Surface sediments collected from Yangtze River in the downtown area of Chongqing were found to contain PAH concentrations to various different degrees. Two bacteria strains (termed PJ1 and PJ2) isolated from the sediment samples could use phenanthrene (Phe) and fluoranthene (Flu) as carbon sources for growth thereby degrading these two PAH compounds. Using 16S rDNA gene sequencing, the isolates were identified as Sphingomonas sp. and Klebsiella sp., respectively. Biodegradation assays showed that the PJ1 presented an efficient degradation capability compared to PJ2 in cultures with the initial Phe and Flu concentrations ranging from 20 to 200 mg/L. The highest rates of Phe and Flu biodegradation by PJ1 reached 74.32% and 58.18% after incubation for 15 and 30 days, respectively. This is the first report on the biodegradation potential of the bacterial from surface sediments of an industrial area upstream of the Gorge Reservoir.

  16. Advances in the field of high-molecular-weight polycyclic aromatic hydrocarbon biodegradation by bacteria.

    Science.gov (United States)

    Kanaly, Robert A; Harayama, Shigeaki

    2010-03-01

    Interest in understanding prokaryotic biotransformation of high-molecular-weight polycyclic aromatic hydrocarbons (HMW PAHs) has continued to grow and the scientific literature shows that studies in this field are originating from research groups from many different locations throughout the world. In the last 10 years, research in regard to HMW PAH biodegradation by bacteria has been further advanced through the documentation of new isolates that represent diverse bacterial types that have been isolated from different environments and that possess different metabolic capabilities. This has occurred in addition to the continuation of in-depth comprehensive characterizations of previously isolated organisms, such as Mycobacterium vanbaalenii PYR-1. New metabolites derived from prokaryotic biodegradation of four- and five-ring PAHs have been characterized, our knowledge of the enzymes involved in these transformations has been advanced and HMW PAH biodegradation pathways have been further developed, expanded upon and refined. At the same time, investigation of prokaryotic consortia has furthered our understanding of the capabilities of microorganisms functioning as communities during HMW PAH biodegradation.

  17. Hydrothermally generated aromatic compounds are consumed by bacteria colonizing in Atlantis II Deep of the Red Sea

    KAUST Repository

    Wang, Yong

    2011-04-28

    Hydrothermal ecosystems have a wide distribution on Earth and many can be found in the basin of the Red Sea. Production of aromatic compounds occurs in a temperature window of 60-150 °C by utilizing organic debris. In the past 50 years, the temperature of the Atlantis II Deep brine pool in the Red Sea has increased from 56 to 68 °C, whereas the temperature at the nearby Discovery Deep brine pool has remained relatively stable at about 44 °C. In this report, we confirmed the presence of aromatic compounds in the Atlantis II brine pool as expected. The presence of the aromatic compounds might have disturbed the microbes in the Atlantis II. To show shifted microbial communities and their metabolisms, we sequenced the metagenomes of the microbes from both brine pools. Classification based on metareads and the 16S rRNA gene sequences from clones showed a strong divergence of dominant bacterial species between the pools. Bacteria capable of aromatic degradation were present in the Atlantis II brine pool. A comparison of the metabolic pathways showed that several aromatic degradation pathways were significantly enriched in the Atlantis II brine pool, suggesting the presence of aromatic compounds. Pathways utilizing metabolites derived from aromatic degradation were also significantly affected. In the Discovery brine pool, the most abundant genes from the microbes were related to sugar metabolism pathways and DNA synthesis and repair, suggesting a different strategy for the utilization of carbon and energy sources between the Discovery brinse pool and the Atlantis II brine pool. © 2011 International Society for Microbial Ecology. All rights reserved.

  18. Hydrothermally generated aromatic compounds are consumed by bacteria colonizing in Atlantis II Deep of the Red Sea.

    Science.gov (United States)

    Wang, Yong; Yang, Jiangke; Lee, On On; Dash, Swagatika; Lau, Stanley C K; Al-Suwailem, Abdulaziz; Wong, Tim Y H; Danchin, Antoine; Qian, Pei-Yuan

    2011-10-01

    Hydrothermal ecosystems have a wide distribution on Earth and many can be found in the basin of the Red Sea. Production of aromatic compounds occurs in a temperature window of ∼60-150 °C by utilizing organic debris. In the past 50 years, the temperature of the Atlantis II Deep brine pool in the Red Sea has increased from 56 to 68 °C, whereas the temperature at the nearby Discovery Deep brine pool has remained relatively stable at about 44 °C. In this report, we confirmed the presence of aromatic compounds in the Atlantis II brine pool as expected. The presence of the aromatic compounds might have disturbed the microbes in the Atlantis II. To show shifted microbial communities and their metabolisms, we sequenced the metagenomes of the microbes from both brine pools. Classification based on metareads and the 16S rRNA gene sequences from clones showed a strong divergence of dominant bacterial species between the pools. Bacteria capable of aromatic degradation were present in the Atlantis II brine pool. A comparison of the metabolic pathways showed that several aromatic degradation pathways were significantly enriched in the Atlantis II brine pool, suggesting the presence of aromatic compounds. Pathways utilizing metabolites derived from aromatic degradation were also significantly affected. In the Discovery brine pool, the most abundant genes from the microbes were related to sugar metabolism pathways and DNA synthesis and repair, suggesting a different strategy for the utilization of carbon and energy sources between the Discovery brine pool and the Atlantis II brine pool.

  19. Marine coastal sediments microbial hydrocarbon degradation processes: contribution of experimental ecology in the omics'era.

    Science.gov (United States)

    Cravo-Laureau, Cristiana; Duran, Robert

    2014-01-01

    Coastal marine sediments, where important biological processes take place, supply essential ecosystem services. By their location, such ecosystems are particularly exposed to human activities as evidenced by the recent Deepwater Horizon disaster. This catastrophe revealed the importance to better understand the microbial processes involved on hydrocarbon degradation in marine sediments raising strong interests of the scientific community. During the last decade, several studies have shown the key role played by microorganisms in determining the fate of hydrocarbons in oil-polluted sediments but only few have taken into consideration the whole sediment's complexity. Marine coastal sediment ecosystems are characterized by remarkable heterogeneity, owning high biodiversity and are subjected to fluctuations in environmental conditions, especially to important oxygen oscillations due to tides. Thus, for understanding the fate of hydrocarbons in such environments, it is crucial to study microbial activities, taking into account sediment characteristics, physical-chemical factors (electron acceptors, temperature), nutrients, co-metabolites availability as well as sediment's reworking due to bioturbation activities. Key information could be collected from in situ studies, which provide an overview of microbial processes, but it is difficult to integrate all parameters involved. Microcosm experiments allow to dissect in-depth some mechanisms involved in hydrocarbon degradation but exclude environmental complexity. To overcome these lacks, strategies have been developed, by creating experiments as close as possible to environmental conditions, for studying natural microbial communities subjected to oil pollution. We present here a review of these approaches, their results and limitation, as well as the promising future of applying "omics" approaches to characterize in-depth microbial communities and metabolic networks involved in hydrocarbon degradation. In addition, we

  20. Marine coastal sediments microbial hydrocarbon degradation processes: contribution of experimental ecology in the omics’era

    Directory of Open Access Journals (Sweden)

    Cristiana eCravo-Laureau

    2014-02-01

    Full Text Available Coastal marine sediments, where important biological processes take place, supply essential ecosystem services. By their location, such ecosystems are particularly exposed to human activities as evidenced by the recent Deepwater Horizon disaster. This catastrophe revealed the importance to better understand the microbial processes involved on hydrocarbon degradation in marine sediments raising strong interests of the scientific community. During the last decade, several studies have shown the key role played by microorganisms in determining the fate of hydrocarbons in oil-polluted sediments but only few have taken into consideration the whole sediment’s complexity. Marine coastal sediment ecosystems are characterized by remarkable heterogeneity, owning high biodiversity and are subjected to fluctuations in environmental conditions, especially to important oxygen oscillations due to tides. Thus, for understanding the fate of hydrocarbons in such environments, it is crucial to study microbial activities, taking into account sediment characteristics, physical-chemical factors (electron acceptors, temperature, nutrients, co-metabolites availability as well as sediment’s reworking due to bioturbation activities. Key information could be collected from in situ studies, which provide an overview of microbial processes, but it is difficult to integrate all parameters involved. Microcosm experiments allow to dissect in-depth some mechanisms involved in hydrocarbon degradation but exclude environmental complexity. To overcome these lacks, strategies have been developed, by creating experiments as close as possible to environmental conditions, for studying natural microbial communities subjected to oil pollution. We present here a review of these approaches, their results and limitation, as well as the promising future of applying ‘omics’ approaches to characterize in-depth microbial communities and metabolic networks involved in hydrocarbon

  1. Characterization of the transcriptome of Achromobacter sp. HZ01 with the outstanding hydrocarbon-degrading ability.

    Science.gov (United States)

    Hong, Yue-Hui; Deng, Mao-Cheng; Xu, Xiao-Ming; Wu, Chou-Fei; Xiao, Xi; Zhu, Qing; Sun, Xian-Xian; Zhou, Qian-Zhi; Peng, Juan; Yuan, Jian-Ping; Wang, Jiang-Hai

    2016-06-15

    Microbial remediation has become one of the most important strategies for eliminating petroleum pollutants. Revealing the transcript maps of microorganisms with the hydrocarbon-degrading ability contributes to enhance the degradation of hydrocarbons and further improve the effectiveness of bioremediation. In this study, we characterized the transcriptome of hydrocarbon-degrading Achromobacter sp. HZ01 after petroleum treatment for 16h. A total of 38,706,280 and 38,954,413 clean reads were obtained by RNA-seq for the petroleum-treated group and control, respectively. By an effective de novo assembly, 3597 unigenes were obtained, including 3485 annotated transcripts. Petroleum treatment had significantly influenced the transcriptional profile of strain HZ01, involving 742 differentially expressed genes. A part of genes were activated to exert specific physiological functions, whereas more genes were down-regulated including specific genes related to cell motility, genes associated with glycometabolism, and genes coding for ribosomal proteins. Identification of genes related to petroleum degradation revealed that the fatty acid metabolic pathway and a part of monooxygenases and dehydrogenases were activated, whereas the TCA cycle was inactive. Additionally, terminal oxidation might be a major aerobic pathway for the degradation of n-alkanes in strain HZ01. The newly obtained data contribute to better understand the gene expression profiles of hydrocarbon-degrading microorganisms after petroleum treatment, to further investigate the genetic characteristics of strain HZ01 and other related species and to develop cost-effective and eco-friendly strategies for remediation of crude oil-polluted environments.

  2. EDTA addition enhances bacterial respiration activities and hydrocarbon degradation in bioaugmented and non-bioaugmented oil-contaminated desert soils.

    Science.gov (United States)

    Al Kharusi, Samiha; Abed, Raeid M M; Dobretsov, Sergey

    2016-03-01

    The low number and activity of hydrocarbon-degrading bacteria and the low solubility and availability of hydrocarbons hamper bioremediation of oil-contaminated soils in arid deserts, thus bioremediation treatments that circumvent these limitations are required. We tested the effect of Ethylenediaminetetraacetic acid (EDTA) addition, at different concentrations (i.e. 0.1, 1 and 10 mM), on bacterial respiration and biodegradation of Arabian light oil in bioaugmented (i.e. with the addition of exogenous alkane-degrading consortium) and non-bioaugmented oil-contaminated desert soils. Post-treatment shifts in the soils' bacterial community structure were monitored using MiSeq sequencing. Bacterial respiration, indicated by the amount of evolved CO2, was highest at 10 mM EDTA in bioaugmented and non-bioaugmented soils, reaching an amount of 2.2 ± 0.08 and 1.6 ± 0.02 mg-CO2 g(-1) after 14 days of incubation, respectively. GC-MS revealed that 91.5% of the C14-C30 alkanes were degraded after 42 days when 10 mM EDTA and the bacterial consortium were added together. MiSeq sequencing showed that 78-91% of retrieved sequences in the original soil belonged to Deinococci, Alphaproteobacteria, Gammaproteobacteia and Bacilli. The same bacterial classes were detected in the 10 mM EDTA-treated soils, however with slight differences in their relative abundances. In the bioaugmented soils, only Alcanivorax sp. MH3 and Parvibaculum sp. MH21 from the exogenous bacterial consortium could survive until the end of the experiment. We conclude that the addition of EDTA at appropriate concentrations could facilitate biodegradation processes by increasing hydrocarbon availability to microbes. The addition of exogenous oil-degrading bacteria along with EDTA could serve as an ideal solution for the decontamination of oil-contaminated desert soils.

  3. Sequential Isolation of Saturated, Aromatic, Resinic and Asphaltic Fractions Degrading Bacteria from Oil Contaminated Soil in South Sumatera

    Directory of Open Access Journals (Sweden)

    Pingkan Aditiawati

    2012-04-01

    Full Text Available Sequential isolation has been conducted to obtain isolates of saturated, aromatic, resin, and asphaltene fractions degrading bacteria from oil contaminated sites. Five soil samples were collected from South Sumatera. These were analyzed using soil extract medium enriched with oil recovery or Remaining-Oil recovery Degradated (ROD as sole carbon and energy sources according to the isolation stage. ROD at the end of every isolation stage analyzed oil fractions by use of the SARA analysis method. Six isolates of bacteria have been selected, one isolate was fraction saturates degrading bacteria that are Mycobacterium sp. T1H2D4-7 at degradation rate 0.0199 mgs/h with density 8.4x106 cfu/g from stage I. The isolate T2H1D2-4, identified as Pseudomonas sp. was fraction aromatics degrading bacteria at accelerate 0.0141 mgs/h with density 5.1x106 cfu/g are obtained at stage II. Two isolates namely Micrococcus sp. T3H2D4-2 and Pseudomonas sp. T1H1D5-5 were fraction resins degrading bacteria by accelerate 0.0088 mgs/h at density 5.6x106 cfu/g and 0.0089 mgs/h at density 5.7x106 cfu/g are obtained at stage III. Isolation of stage IV has been obtained two isolates Pseudomonas sp. T4H1D3-1and Pseudomonas sp. T4H3D5-4 were fraction asphaltenes degrading bacteria by accelerate 0.0057 mgs/h at density 5.6x106 cfu/g and accelerate 0.0058 mgs/h at density 5.7x106 cfu/g.

  4. Determination of the hydrocarbon-degrading metabolic capabilities of tropical bacterial isolates

    Energy Technology Data Exchange (ETDEWEB)

    Marquez-Rocha, F.J.; Olmos-Soto, J. [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, San Diego, CA (United States). Departamento de Biotecnologia Marina; Rosano-Hernandez, M.A.; Muriel-Garcia, M. [Instituto Mexicano del Petroleo, CD Carmen Camp (Mexico). Zona Marina/Tecnologia Ambiental

    2005-01-01

    Of more than 20 bacteria isolated from a tropical soil using minimal medium supplemented with hydrocarbons, 11 grew well on diesel as sole carbon source, and another 11 grew in the presence of polynuclear aromatic hydrocarbons (PAHs). Ten isolates were identified phenotypically as Pseudomonas sp. and eight as Bacillus sp. Gene sequences representing the catabolic genes (alkM, todM, ndoM, and xylM) and 16S rRNA gene sequences characteristic for Pseudomona and Bacillus were amplified by PCR, using DNA recovered from the supernatant of hydrocarbon-contaminated soil suspensions. Based on their rapid growth characteristics in the presence of hydrocarbons and the formation of PCR products for the catabolic genes alkM and ndoM six isolates were selected for biodegradation assays. After 30 days a mixed culture of two isolates achieved close to 70% hydrocarbon removal and apparent mineralization of 16% of the hydrocarbons present in the soil. Biodegradation rates varied from 275 to 387 mg hydrocarbon kg{sup -1} day{sup -1}. Several bacterial isolates obtained in this study have catabolic capabilities for the biodegradation of alkanes and aromatic hydrocarbons including PAHs. (author)

  5. Impact of hydrocarbons, PCBs and heavy metals on bacterial communities in Lerma River, Salamanca, Mexico: Investigation of hydrocarbon degradation potential.

    Science.gov (United States)

    Brito, Elcia M S; De la Cruz Barrón, Magali; Caretta, César A; Goñi-Urriza, Marisol; Andrade, Leandro H; Cuevas-Rodríguez, Germán; Malm, Olaf; Torres, João P M; Simon, Maryse; Guyoneaud, Remy

    2015-07-15

    Freshwater contamination usually comes from runoff water or direct wastewater discharges to the environment. This paper presents a case study which reveals the impact of these types of contamination on the sediment bacterial population. A small stretch of Lerma River Basin, heavily impacted by industrial activities and urban wastewater release, was studied. Due to industrial inputs, the sediments are characterized by strong hydrocarbon concentrations, ranging from 2 935 to 28 430μg·kg(-1) of total polyaromatic hydrocarbons (PAHs). These sediments are also impacted by heavy metals (e.g., 9.6μg·kg(-1) of Cd and 246μg·kg(-1) of Cu, about 8 times the maximum recommended values for environmental samples) and polychlorinated biphenyls (ranging from 54 to 123μg·kg(-1) of total PCBs). The bacterial diversity on 6 sediment samples, taken from upstream to downstream of the main industrial and urban contamination sources, was assessed through TRFLP. Even though the high PAH concentrations are hazardous to aquatic life, they are not the only factor driving bacterial community composition in this ecosystem. Urban discharges, leading to hypoxia and low pH, also strongly influenced bacterial community structure. The bacterial bioprospection of these samples, using PAH as unique carbon source, yielded 8 hydrocarbonoclastic strains. By sequencing the 16S rDNA gene, these were identified as similar to Mycobacterium goodii, Pseudomonas aeruginosa, Pseudomonas lundensis or Aeromonas veronii. These strains showed high capacity to degrade naphthalene (between 92 and 100% at 200mg·L(-1)), pyrene (up to 72% at 100mg·L(-1)) and/or fluoranthene (52% at 50mg·L(-1)) as their only carbon source on in vitro experiments. These hydrocarbonoclastic bacteria were detected even in the samples upstream of the city of Salamanca, suggesting chronical contamination, already in place longer before. Such microorganisms are clearly potential candidates for hydrocarbon degradation in the

  6. Highly Active and Stable Large Catalase Isolated from a Hydrocarbon Degrading Aspergillus terreus MTCC 6324

    Directory of Open Access Journals (Sweden)

    Preety Vatsyayan

    2016-01-01

    Full Text Available A hydrocarbon degrading Aspergillus terreus MTCC 6324 produces a high level of extremely active and stable cellular large catalase (CAT during growth on n-hexadecane to combat the oxidative stress caused by the hydrocarbon degrading metabolic machinery inside the cell. A 160-fold purification with specific activity of around 66 × 105 U mg−1 protein was achieved. The native protein molecular mass was 368 ± 5 kDa with subunit molecular mass of nearly 90 kDa, which indicates that the native CAT protein is a homotetramer. The isoelectric pH (pI of the purified CAT was 4.2. BLAST aligned peptide mass fragments of CAT protein showed its highest similarity with the catalase B protein from other fungal sources. CAT was active in a broad range of pH 4 to 12 and temperature 25°C to 90°C. The catalytic efficiency (Kcat/Km of 4.7 × 108 M−1 s−1 within the studied substrate range and alkaline pH stability (half-life, t1/2 at pH 12~15 months of CAT are considerably higher than most of the extensively studied catalases from different sources. The storage stability (t1/2 of CAT at physiological pH 7.5 and 4°C was nearly 30 months. The haem was identified as haem b by electrospray ionization tandem mass spectroscopy (ESI-MS/MS.

  7. Bacteria from Wheat and Cucurbit Plant Roots Metabolize PAHs and Aromatic Root Exudates: Implications for Rhizodegradation

    DEFF Research Database (Denmark)

    Ely, Cairn S; Smets, Barth F.

    2017-01-01

    for growth on anthracene and chrysene on PAH-amended plates. Rhizosphere isolates metabolized 3- and 4-ring PAHs and PAH catabolic intermediates in liquid incubations. Aromatic root exudate compounds, namely flavonoids and simple phenols, were also substrates for isolated rhizobacteria. In particular...

  8. Distribution of endophytic bacteria in Alopecurus aequalis Sobol and Oxalis corniculata L. from soils contaminated by polycyclic aromatic hydrocarbons.

    Directory of Open Access Journals (Sweden)

    Anping Peng

    Full Text Available The distributions of endophytic bacteria in Alopecurus aequalis Sobol and Oxalis corniculata L. grown in soils contaminated with different levels of polycyclic aromatic hydrocarbons (PAHs were investigated with polymerase chain reaction followed by denaturing gradient gel electrophoresis technology (PCR-DGGE and cultivation methods. Twelve types of PAHs, at concentrations varying from 0.16 to 180 mg·kg(-1, were observed in the roots and shoots of the two plants. The total PAH concentrations in Alopecurus aequalis Sobol obtained from three different PAH-contaminated stations were 184, 197, and 304 mg·kg(-1, and the total PAH concentrations in Oxalis corniculata L. were 251, 346, and 600 mg·kg(-1, respectively. The PCR-DGGE results showed that the endophytic bacterial communities in the roots and shoots of the two plants were quite different, although most bacteria belonged to Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes. A total of 68 endophytic bacterial strains were isolated from different tissues of the two plants and classified into three phyla: Firmicutes, Proteobacteria and Bacteroidetes. In both plants, Bacillus spp. and Pseudomonas spp. were the dominant cultivable populations. With an increase in the PAH pollution level, the diversity and distribution of endophytic bacteria in the two plants changed correspondingly, and the number of cultivable endophytic bacterial strains decreased rapidly. Testing of the isolated endophytic bacteria for tolerance to each type of PAH showed that most isolates could grow well on Luria-Bertani media in the presence of different PAHs, and some isolates were able to grow rapidly on a mineral salt medium with a single PAH as the sole carbon and energy source, indicating that these strains may have the potential to degrade PAHs in plants. This research provides the first insight into the characteristics of endophytic bacterial populations under different PAH pollution levels and provides a

  9. In silico and experimental methods revealed highly diverse bacteria with quorum sensing and aromatics biodegradation systems--a potential broad application on bioremediation.

    Science.gov (United States)

    Huang, Yili; Zeng, Yanhua; Yu, Zhiliang; Zhang, Jing; Feng, Hao; Lin, Xiuchun

    2013-11-01

    Phylogenetic overlaps between aromatics-degrading bacteria and acyl-homoserine-lactone (AHL) or autoinducer (AI) based quorum-sensing (QS) bacteria were evident in literatures; however, the diversity of bacteria with both activities had never been finely described. In-silico searching in NCBI genome database revealed that more than 11% of investigated population harbored both aromatic ring-hydroxylating-dioxygenase (RHD) gene and AHL/AI-synthetase gene. These bacteria were distributed in 10 orders, 15 families, 42 genus and 78 species. Horizontal transfers of both genes were common among them. Using enrichment and culture dependent method, 6 Sphingomonadales and 4 Rhizobiales with phenanthrene- or pyrene-degrading ability and AHL-production were isolated from marine, wetland and soil samples. Thin-layer-chromatography and gas-chromatography-mass-spectrum revealed that these Sphingomonads produced various AHL molecules. This is the first report of highly diverse bacteria that harbored both aromatics-degrading and QS systems. QS regulation may have broad impacts on aromatics biodegradation, and would be a new angle for developing bioremediation technology.

  10. Microcosm-based interaction studies between members of two ecophysiological groups of bioemulsifier producer and a hydrocarbon degrader from the Indian intertidal zone.

    Science.gov (United States)

    Markande, A R; Nerurkar, A S

    2016-07-01

    Isolates were obtained from intertidal zone site samples from all five western and one eastern coastal states of India and were screened. These ecophysiological groups of aerobic, mesophilic, heterotrophic, sporulating, and bioemulsifier-producing bacteria were from Planococcaceae and Bacillaceae. This is the first report of bioemulsifier production by Sporosarcina spp., Lysinibacillus spp., B. thuringiensis, and B. flexus. In this group, Solibacillus silvestris AM1 was found to produce the highest emulsification activity (62.5 %EI) and the sample that yielded it was used to isolate the ecophysiological group of non-bioemulsifier-producing, hydrocarbon-degrading bacteria (belonging to Chromatiales and Bacillales). These yielded hitherto unreported degrader, Rheinheimera sp. CO6 which was selected for the interaction studies (in a microcosm) with bioemulsifier-producing S. silvestris AM1. The gas chromatographic study of these microcosm experiments revealed increased degradation of benzene, toluene, and xylene (BTX) and the growth of Rheinheimera sp. CO6 in the presence of bioemulsifier produced by S. silvestris AM1. Enhancement of the growth of S. silvestris AM1 in the presence of Rheinheimera sp. CO6 was observed possibly due to reduced toxicity of BTX suggesting mutualistic association between the two. This study elucidates the presence and interaction between enhancers and degraders in a hydrocarbon-contaminated intertidal zone and contributes to the knowledge during application of the two in remediation processes.

  11. Degradation Characteristics and Community Structure of a Hydrocarbon Degrading Bacterial Consortium

    Institute of Scientific and Technical Information of China (English)

    Li Zheng; Gu Guizhou; Zhao Chaocheng; Zhao Dongfeng

    2015-01-01

    A hydrocarbon degrading bacterial consortium KO5-2 was isolated from oil-contaminated soil of Karamay in Xinjiang, China, which could remove 56.9%of 10 g/L total petroleum hydrocarbons (TPH) at 30℃after 7 days of incu-bation, and could also remove 100%of lfuorene, 98.93%of phenanthrene and 65.73%of pyrene within 3, 7 and 9 days, respectively. Twelve strains from six different genera were isolated from KO5-2 and only eight ones were able to utilize the TPH. The denaturing gradient gel electrophoresis (DGGE) was used to investigate the microbial community shifts in ifve different carbon sources (including TPH, saturated hydrocarbons, lfuorene, phenanthrene and pyrene). The test results indi-cated that the community compositions of KO5-2 in carbon sources of TPH and saturated hydrocarbons, respectively, were roughly the same, while they were distinctive in the three different carbon sources of PAHs. Rhodococcus sp. and Pseudo-monas sp. could survive in the ifve kinds of carbon sources. Bacillus sp., Sphingomonas sp. and Ochrobactrum sp. likely played key roles in the degradation of saturated hydrocarbons, PAHs and phenanthrene, respectively. This study showed that speciifc bacterial phylotypes were associated with different contaminants and complex interactions between bacterial spe-cies, and the medium conditions inlfuenced the biodegradation capacity of the microbial communities involved in bioreme-diation processes.

  12. In situ biodegradation potential of aromatic hydrocarbons in anaerobic groundwaters

    Science.gov (United States)

    Acton, D. W.; Barker, J. F.

    1992-04-01

    Three types of experiments were conducted to assess the potential for enhancing the in situ biodegradation of nine aromatic hydrocarbons in anaerobic, leachate-impacted aquifers at North Bay, Ontario, and at Canada Forces Base Borden. Laboratory micrososms containing authentic aquifer material and groundwater from the North Bay site were amended with nitrate and glucose. No significant losses of aromatic hydrocarbons were observed compared to unamended controls, over a period of 187 days. A total of eight in situ biodegradation columns were installed in the North Bay and Borden aquifers. Remedial additions included electron acceptors (nitrate and sulphate) and primary substrates (acetate, lactate and yeast extract). Six aromatic hydrocarbons [toluene, ethylbenzene, m-xylene, o-xylene, cumene and 1,2,4-trimethylbenzene ( 1,2,4-TMB)] were completely degraded in at least one in situ column at the North Bay site. Only toluene was degraded in the Borden aquifer. In all cases, aromatic hydrocarbon attenuation was attributed to biodegradation by methanogenic and fermentative bacteria. No evidence of aromatic hydrocarbon degradation was observed in columns remediated with nitrate or primary substrates. A continuous forced gradient injection experiment with sulphate addition was conducted at the North Bay site over a period of 51 days. The concentration of six aromatic hydrocarbons was monitored over time in the injection wells and at piezometer fences located 2, 5 and 10 m downgradient. All compounds except toluene reached injection concentration between 14 and 26 days after pumping began, and showed some evidence of selective retardation. Toluene broke through at a subdued concentration (˜ 50% of injection levels), and eventually declined to undetectable levels on day 43. This attenuation was attributed to adaptation and biodegradation by anaerobic bacteria. The results from these experiments indicate that considerable anaerobic biodegradation of aromatic hydrocarbons in

  13. Draft genome sequence of the polycyclic aromatic hydrocarbon-degrading, genetically engineered bioluminescent bioreporter Pseudomonas fluorescens HK44.

    Science.gov (United States)

    Chauhan, Archana; Layton, Alice C; Williams, Daniel E; Smartt, Abby E; Ripp, Steven; Karpinets, Tatiana V; Brown, Steven D; Sayler, Gary S

    2011-09-01

    Pseudomonas fluorescens strain HK44 (DSM 6700) is a genetically engineered lux-based bioluminescent bioreporter. Here we report the draft genome sequence of strain HK44. Annotation of ∼6.1 Mb of sequence indicates that 30% of the traits are unique and distributed over five genomic islands, a prophage, and two plasmids.

  14. Draft Genome Sequence of the Polycyclic Aromatic Hydrocarbon-Degrading, Genetically Engineered Bioluminescent Bioreporter Pseudomonas fluorescens HK44 ▿

    Science.gov (United States)

    Chauhan, Archana; Layton, Alice C.; Williams, Daniel E.; Smartt, Abby E.; Ripp, Steven; Karpinets, Tatiana V.; Brown, Steven D.; Sayler, Gary S.

    2011-01-01

    Pseudomonas fluorescens strain HK44 (DSM 6700) is a genetically engineered lux-based bioluminescent bioreporter. Here we report the draft genome sequence of strain HK44. Annotation of ∼6.1 Mb of sequence indicates that 30% of the traits are unique and distributed over five genomic islands, a prophage, and two plasmids. PMID:21742869

  15. Draft Genome Sequence of the Polycyclic Aromatic Hydrocarbon-Degrading, Genetically Engineered Bioluminescent Bioreporter Pseudomonas fluorescens HK44

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, Archana [ORNL; Layton, Alice [University of Tennessee, Knoxville (UTK); Williams, Daniel W [ORNL; Smart, Abby E. [University of Tennessee, Knoxville (UTK); Ripp, Steven Anthony [ORNL; Karpinets, Tatiana V [ORNL; Brown, Steven D [ORNL; Sayler, Gary Steven [ORNL

    2011-01-01

    Pseudomonas fluorescens strain HK44 (DSM 6700) is a genetically engineered lux-based bioluminescent bioreporter. Here we report the draft genome sequence of strain HK44. Annotation of {approx}6.1 Mb sequence indicates that 30% of the traits are unique and distributed over 5 genomic islands, a prophage and two plasmids.

  16. Structure, Function and Expression Regulation of Hydrocarbon-degrading Enzymes and Their Encoding Genes%石油烃降解酶及其基因的结构、功能和表达调控

    Institute of Scientific and Technical Information of China (English)

    于寒颖; 杨慧

    2012-01-01

    The research on the enzymes and genes involving in hydrocarbon biodegradation is the important basis of molecular assay of petroleum microbes and construction of the engineering strains. In this review, the recent advances of structures, functions and regulations of hydrocarbon-degrading enzymes and the corresponding genes were summarized. The first enzymes in the aerobic metabolism pathways of hydrocarbon included several types of oxydases. Among them, the crystal structures of particulate methane monooxygenase protomer, the terminal oxygenase component of cumene dioxygenase and naphthalene dioxygenase were reported. The aryl-succinate or alkyl-succinate synthase were the first basic enzymes in the anaerobic transformation of hydrocarbon while ethylbenzene dehydrogenase catalyzed the initial reaction of anaerobic degradation of ethylbenzene in Azoarcus sp. For bacteria, the hydrocarbon-degrading genes consisting of operons and their transcriptions were induced by hydrocarbon or analogues and limited by global cell control. Some microorganisms possessed the complicated hydrocarbon-degrading regulations which were consistent with their various hydrocarbon metabolism pathways. In addition, the related study on ecology indicated that the induction process of genes involving in the hydrocarbon degradation in the environment were different from that of the culture in the laboratory. Based on the analysis of the unsolved questions of construction the hydrocarbon-degrading engineering bacteria, the significance of research on the comprehensive regulation of hydrocarbon metabolism in the cells and the induction of the related enzymes and genes in the environment was proposed. The application of the enzymes and genes, involving in hydrocarbon biodegradation, for the theoretic research on toxicant degradation and bioremediation in the future was prospected.%研究烃降解酶及其基因是进行石油微生物分子检测和工程菌构建的重要基础.本文对目前烃

  17. In situ biostimulation of petroleum hydrocarbon degradation by nitrate and phosphate injection using a dipole well configuration

    Science.gov (United States)

    Ponsin, Violaine; Coulomb, Bruno; Guelorget, Yves; Maier, Joachim; Höhener, Patrick

    2014-12-01

    The main aim of this study was to explore the feasibility of source zone bioremediation by nitrate and nutrient injection in a crude-oil contaminated aquifer using a recirculating well dipole. Groundwater pumped from a downgradient well at a rate of 2.5 m3 h- 1 was enriched with bromide (tracer), nitrate and ammonium phosphate and injected in a well 40 m upgradient. The test was run for 49 days with solute injection, followed by 65 days of dipole operation without solute addition. The resulting bromide breakthrough curve allowed quantifying a first-order leakage coefficient of 0.017 day- 1 from the dipole, whereas from the nitrate data a first-order nitrate consumption rate of 0.075 day- 1 was determined. Dissolved hydrocarbon concentrations including benzene decreased to non-detect in 84 days but experienced important rebounds after ending circulation. Nitrite accumulated temporarily but was consumed entirely when solute injection stopped. The mass balance calculations revealed that about 83% of the nitrate was used for hydrocarbon degradation, with the remaining being used for oxidation of reduced sulfur. A reactive transport model was used for the delineation of the treated zone. This model suggested that denitrification influenced flow and transport in the dipole. It is concluded that successful promotion of denitrifying hydrocarbon degradation is easily obtained in this aquifer and enables to abate dissolved concentrations, and that dipole configuration is a good option.

  18. Detection and quantification of hydrocarbon-degrading bacteria in petroleum samples using group-specific primer sets

    OpenAIRE

    Elaine Crespim

    2008-01-01

    Resumo: A abordagem tradicional empregada em estudos de Microbiologia Ambiental, baseada em métodos de isolamento seletivo e cultivo de microrganismos em laboratório, embora seja útil para a determinação do potencial fisiológico dos organismos isolados, é inadequada para a realização de uma caracterização abrangente da comunidade microbiana destes ambientes ou para detectar microrganismos de difícil cultivo ou que vivem em consórcios. O emprego de técnicas moleculares em estudos de comunidade...

  19. Draft Genome Sequence of the Hydrocarbon-Degrading Bacterium Alcanivorax dieselolei KS-293 Isolated from Surface Seawater in the Eastern Mediterranean Sea

    KAUST Repository

    Barbato, Marta

    2015-12-10

    We report here the draft genome sequence of Alcanivorax dieselolei KS-293, a hydrocarbonoclastic bacterium isolated from the Mediterranean Sea, by supplying diesel oil as the sole carbon source. This strain contains multiple putative genes associated with hydrocarbon degradation pathways and that are highly similar to those described in A. dieselolei type strain B5.

  20. Complete Genome Sequence of Bacillus pumilus PDSLzg-1, a Hydrocarbon-Degrading Bacterium Isolated from Oil-Contaminated Soil in China

    Science.gov (United States)

    Hao, Kun; Li, Hongna; Li, Feng

    2016-01-01

    Bacillus pumilus strain PDSLzg-1, an efficient hydrocarbon-degrading bacterium, was isolated from oil-contaminated soil. Here, we present the complete sequence of its circular chromosome and circular plasmid. The genomic information is essential for the study of degradation of oil by B. pumilus PDSLzg-1.

  1. Complete Genome Sequence of a Bacterium Representing a Deep Uncultivated Lineage within the Gammaproteobacteria Associated with the Degradation of Polycyclic Aromatic Hydrocarbons

    Science.gov (United States)

    Dickey, Allison N.; Scholl, Elizabeth H.; Wright, Fred A.; Aitken, Michael D.

    2016-01-01

    The bacterial strain TR3.2, representing a novel deeply branching lineage within the Gammaproteobacteria, was isolated and its genome sequenced. This isolate is the first cultivated representative of the previously described “Pyrene Group 2” (PG2) and represents a variety of environmental sequences primarily associated with petrochemical contamination and aromatic hydrocarbon degradation.

  2. Hydroxysteroid dehydrogenases (HSDs) in bacteria: a bioinformatic perspective.

    Science.gov (United States)

    Kisiela, Michael; Skarka, Adam; Ebert, Bettina; Maser, Edmund

    2012-03-01

    Steroidal compounds including cholesterol, bile acids and steroid hormones play a central role in various physiological processes such as cell signaling, growth, reproduction, and energy homeostasis. Hydroxysteroid dehydrogenases (HSDs), which belong to the superfamily of short-chain dehydrogenases/reductases (SDR) or aldo-keto reductases (AKR), are important enzymes involved in the steroid hormone metabolism. HSDs function as an enzymatic switch that controls the access of receptor-active steroids to nuclear hormone receptors and thereby mediate a fine-tuning of the steroid response. The aim of this study was the identification of classified functional HSDs and the bioinformatic annotation of these proteins in all complete sequenced bacterial genomes followed by a phylogenetic analysis. For the bioinformatic annotation we constructed specific hidden Markov models in an iterative approach to provide a reliable identification for the specific catalytic groups of HSDs. Here, we show a detailed phylogenetic analysis of 3α-, 7α-, 12α-HSDs and two further functional related enzymes (3-ketosteroid-Δ(1)-dehydrogenase, 3-ketosteroid-Δ(4)(5α)-dehydrogenase) from the superfamily of SDRs. For some bacteria that have been previously reported to posses a specific HSD activity, we could annotate the corresponding HSD protein. The dominating phyla that were identified to express HSDs were that of Actinobacteria, Proteobacteria, and Firmicutes. Moreover, some evolutionarily more ancient microorganisms (e.g., Cyanobacteria and Euryachaeota) were found as well. A large number of HSD-expressing bacteria constitute the normal human gastro-intestinal flora. Another group of bacteria were originally isolated from natural habitats like seawater, soil, marine and permafrost sediments. These bacteria include polycyclic aromatic hydrocarbons-degrading species such as Pseudomonas, Burkholderia and Rhodococcus. In conclusion, HSDs are found in a wide variety of microorganisms including

  3. Production of biosurfactant by hydrocarbon degrading Rhodococcus ruber and Rhodococcus erythropolis

    Directory of Open Access Journals (Sweden)

    Bicca Flávio Correa

    1999-01-01

    Full Text Available There is world wide concern about the liberation of hydrocarbons in the environment, both from industrial activities and from accidental spills of oil and oilrelated compounds. Biosurfactants, which are natural emulsifiers of hydrocarbons, are produced by some bacteria, fungi and yeast. They are polymers, totally or partially extracellular, with an amphipathyc structure, which allows them to form micelles that accumulate at the interface between liquids of different polarities such as water and oil. This process is based upon the ability of biosurfactants to reduce surface tension, blocking the formation of hydrogen bridges and certain hydrophilic and hydrophobic interactions. The ability of biosurfactant production by five strains of Rhodococcus isolated from oil prospecting sites was evaluated. Surface tension measurement and emulsifying index were used to quantify biosurfactant production. The influence of environmental conditions was also investigated - pH, temperature, medium composition, and type of carbon source - on cell growth and biosurfactant production. Strain AC 239 was shown to be a potential producer, attaining 63% of emulsifying index for a Diesel-water binary system. It could be used, either directly on oil spills in contained environments, or for the biotechnological production of biosurfactant.

  4. Isolation and characterization of different bacterial strains for bioremediation of n-alkanes and polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Guermouche M'rassi, A; Bensalah, F; Gury, J; Duran, R

    2015-10-01

    Crude oil is a common environmental pollutant composed of a large number of both aromatic and aliphatic hydrocarbons. Biodegradation is carried out by microbial communities that are important in determining the fate of pollutants in the environment. The intrinsic biodegradability of the hydrocarbons and the distribution in the environment of competent degrading microorganisms are crucial information for the implementation of bioremediation processes. In the present study, the biodegradation capacities of various bacteria toward aliphatic and aromatic hydrocarbons were determined. The purpose of the study was to isolate and characterize hydrocarbon-degrading bacteria from contaminated soil of a refinery in Arzew, Algeria. A collection of 150 bacterial strains was obtained; the bacterial isolates were identified by 16S rRNA gene sequencing and their ability to degrade hydrocarbon compounds characterized. The isolated strains were mainly affiliated to the Gamma-Proteobacteria class. Among them, Pseudomonas spp. had the ability to metabolize high molecular weight hydrocarbon compounds such as pristane (C19) at 35.11 % by strain LGM22 and benzo[a] pyrene (C20) at 33.93 % by strain LGM11. Some strains were able to grow on all the hydrocarbons tested including octadecane, squalene, phenanthrene, and pyrene. Some strains were specialized degrading only few substrates. In contrast, the strain LGM2 designated as Pseudomonas sp. was found able to degrade both linear and branched alkanes as well as low and high poly-aromatic hydrocarbons (PAHs). The alkB gene involved in alkane degradation was detected in LGM2 and other Pseudomonas-related isolates. The capabilities of the isolated bacterial strains to degrade alkanes and PAHs should be of great practical significance in bioremediation of oil-contaminated environments.

  5. Role of nutrients and illuminance in predicting the fate of fungal mediated petroleum hydrocarbon degradation and biomass production.

    Science.gov (United States)

    Ali Khan, Aqib Hassan; Tanveer, Sundus; Anees, Mariam; Muhammad, Yousaf Shad; Iqbal, Mazhar; Yousaf, Sohail

    2016-07-01

    Biodegradation and biomass production are affected by numerous environmental factors including pH, oxygen availability and presence of pollutants. The present study, for the first time, elucidated the effects of nutrients and light on mycodegradation of petroleum hydrocarbons in diesel oil. Seven fungal strains (Aspergillus terreus FA3, Aspergillus niger FA5, Aspergillus terreus FA6, Penicillium chrysogenum FP4, Aspergillus terreus FP6, Aspergillus flavus FP10, and Candida sp. FG1) were used for hydrocarbon degradation under static conditions, in four combinations of nutrient media and illuminance for 45 days. Highest degradation was achieved by Aspergillus terreus FA6 and Candida sp. FG1 under both conditions of light and dark, with nutrient deprived HAF (Hydrocarbon adopted fungi) broth. Under HAF/Dark diesel oil degradation by FA6 and FG1 was 87.3% and 84.3% respectively, while under HAF/Light both FA6 and FG1 performed 84.3% biodegradation. The highest biomass was produced by Aspergillus flavus FP10 in PDB (Potato dextrose broth)/Dark (109.3 mg). Fungal degradation of petroleum hydrocarbons was negatively affected by the presence of other simpler-to-degrade carbon sources in the medium. The biomass production was enhanced by improved nutrient availability and diminished by illuminance.

  6. Robust hydrocarbon degradation and dynamics of bacterial communities during nutrient-enhanced oil spill bioremediation.

    Science.gov (United States)

    Röling, Wilfred F M; Milner, Michael G; Jones, D Martin; Lee, Kenneth; Daniel, Fabien; Swannell, Richard J P; Head, Ian M

    2002-11-01

    Degradation of oil on beaches is, in general, limited by the supply of inorganic nutrients. In order to obtain a more systematic understanding of the effects of nutrient addition on oil spill bioremediation, beach sediment microcosms contaminated with oil were treated with different levels of inorganic nutrients. Oil biodegradation was assessed respirometrically and on the basis of changes in oil composition. Bacterial communities were compared by numerical analysis of denaturing gradient gel electrophoresis (DGGE) profiles of PCR-amplified 16S rRNA genes and cloning and sequencing of PCR-amplified 16S rRNA genes. Nutrient amendment over a wide range of concentrations significantly improved oil degradation, confirming that N and P limited degradation over the concentration range tested. However, the extent and rate of oil degradation were similar for all microcosms, indicating that, in this experiment, it was the addition of inorganic nutrients rather than the precise amount that was most important operationally. Very different microbial communities were selected in all of the microcosms. Similarities between DGGE profiles of replicate samples from a single microcosm were high (95% +/- 5%), but similarities between DGGE profiles from replicate microcosms receiving the same level of inorganic nutrients (68% +/- 5%) were not significantly higher than those between microcosms subjected to different nutrient amendments (63% +/- 7%). Therefore, it is apparent that the different communities selected cannot be attributed to the level of inorganic nutrients present in different microcosms. Bioremediation treatments dramatically reduced the diversity of the bacterial community. The decrease in diversity could be accounted for by a strong selection for bacteria belonging to the alkane-degrading Alcanivorax/Fundibacter group. On the basis of Shannon-Weaver indices, rapid recovery of the bacterial community diversity to preoiling levels of diversity occurred. However, although

  7. Novel lipopeptide biosurfactant produced by hydrocarbon degrading and heavy metal tolerant bacterium Escherichia fergusonii KLU01 as a potential tool for bioremediation.

    Science.gov (United States)

    Sriram, Muthu Irulappan; Gayathiri, Shanmugakani; Gnanaselvi, Ulaganathan; Jenifer, Paulraj Stanly; Mohan Raj, Subramanian; Gurunathan, Sangiliyandi

    2011-10-01

    Escherichia fergusonii KLU01, a propitious bacterial strain isolated from oil contaminated soil was identified to be hydrocarbon degrading, heavy metal tolerant and a potent producer of biosurfactant using diesel oil as the sole carbon and energy source. The biosurfactant produced by the strain was characterized to be a lipopeptide. The minimum active dose and critical micelle concentration of the biosurfactant were found as 0.165±0.08 μg and 36 mg/L, respectively. In spite of being an excellent emulsifier, the biosurfactant showed an incredible stability at extremes of temperature, pH and at various concentrations of NaCl, CaCl₂ and MgCl₂. Also the bacterium manifested tolerance towards Manganese, Iron, Lead, Nickel, Copper and Zinc. The strain emerges as a new class of biosurfactant producer with potential environmental and industrial applications, especially in hydrocarbon degradation and heavy metal bioremediation.

  8. Draft Genome Sequence of Hydrocarbon-Degrading Staphylococcus saprophyticus Strain CNV2, Isolated from Crude Oil-Contaminated Soil from the Noonmati Oil Refinery, Guwahati, Assam, India.

    Science.gov (United States)

    Mukherjee, Arghya; Chettri, Bobby; Langpoklakpam, James S; Singh, Arvind K; Chattopadhyay, Dhrubajyoti

    2016-05-12

    Here, we report the 2.6 Mb draft genome sequence of hydrocarbon-degrading Staphylococcus saprophyticus strain CNV2, isolated from oil-contaminated soil in Guwahati, India. CNV2 contains 2,545 coding sequences and has a G+C content of 33.2%. This is the first report of the genome sequence of an S. saprophyticus adapted to an oil-contaminated environment.

  9. Research Progress of Aromatic Polyketides in Bacteria%细菌芳香聚酮研究进展

    Institute of Scientific and Technical Information of China (English)

    黄连琴; 黄建忠

    2013-01-01

    鉴于芳香聚酮化合物在抗菌、抗肿瘤、抗病毒等方面具有重要的临床药用价值,该文综述了细菌芳香聚酮化合物及其生物合成研究的主要进展,重点讨论了四类芳香聚酮的生物活性和化学结构以及芳香聚酮生物合成机理研究的基础理论意义。在此基础上对组合生物合成新的具有一定生物活性化合物的研究前景进行了展望。%This article provides a research progress of aromatic polyketide and its biosynthetic logic in light of its significant application pharmaceutically and clinically as noteworthy anticancer,antibacterial,antifungal and antivi-ral substances,with the emphasis on the discussion of four classes of aromatic compounds in bioactivity and chemical structure as well as several fundamental insights on the biosynthetic mechanism.By means of a deeper understanding of the biosynthetic process,it is proposed that combinatorial biosynthesis affords a number of new avenues for creating novel molecular structures that will likely have new biological activity.

  10. Biosurfactant production from marine hydrocarbon-degrading consortia and pure bacterial strains using crude oil as carbon source

    Directory of Open Access Journals (Sweden)

    Eleftheria eAntoniou

    2015-04-01

    Full Text Available Biosurfactants (BS are green amphiphilic molecules produced by microorganisms during biodegradation, increasing the bioavailability of organic pollutants. In this work, the BS production yield of marine hydrocarbon degraders isolated from Elefsina bay in Eastern Mediterranean Sea has been investigated. The drop collapse test was used as a preliminary screening test to confirm biosurfactant producing strains or mixed consortia. The community structure of the best consortia based on the drop collapse test was determined by 16S-rDNA pyrotag screening. Subsequently, the effect of incubation time, temperature, substrate and supplementation with inorganic nutrients, on biosurfactant production, was examined. Two types of BS - lipid mixtures were extracted from the culture broth; the low molecular weight BS Rhamnolipids and Sophorolipids. Crude extracts were purified by silica gel column chromatography and then identified by thin layer chromatography (TLC and Fourier transform infrared spectroscopy (FT-IR. Results indicate that biosurfactant production yield remains constant and low while it is independent of the total culture biomass, carbon source, and temperature. A constant BS concentration in a culture broth with continuous degradation of crude oil implies that the BS producing microbes generate no more than the required amount of biosurfactants that enables biodegradation of the crude oil. Isolated pure strains were found to have higher specific production yields than the complex microbial marine community-consortia. The heavy oil fraction of crude oil has emerged as a promising substrate for BS production (by marine BS producers with fewer impurities in the final product. Furthermore, a particular strain isolated from sediments, Paracoccus marcusii, may be an optimal choice for bioremediation purposes as its biomass remains trapped in the hydrocarbon phase, not suffering from potential dilution effects by sea currents.

  11. Biodegradation of high concentrations of mixed polycyclic aromatic hydrocarbons by indigenous bacteria from a river sediment: a microcosm study and bacterial community analysis.

    Science.gov (United States)

    Muangchinda, Chanokporn; Yamazoe, Atsushi; Polrit, Duangporn; Thoetkiattikul, Honglada; Mhuantong, Wuttichai; Champreda, Verawat; Pinyakong, Onruthai

    2017-02-01

    This study assessed the biodegradation of mixtures of polycyclic aromatic hydrocarbons (PAHs) by indigenous bacteria in river sediment. Microcosms were constructed from sediment from the Chao Phraya River (the main river in Thailand) by supplementation with high concentrations of fluorene, phenanthrene, pyrene (300 mg kg(-1) of each PAH), and acenaphthene (600 mg kg(-1)). Fluorene and phenanthrene were completely degraded, whereas 50% of the pyrene and acenaphthene were removed at the end of the incubation period (70 days). Community analyses revealed the dynamics of the bacterial profiles in the PAH-degrading microcosms after PAH exposure. Actinobacteria predominated and became significantly more abundant in the microcosms after 14 days of incubation at room temperature under aerobic conditions. Furthermore, the remaining PAHs and alpha diversity were positively correlated. The sequencing of clone libraries of the PAH-RHDα genes also revealed that the dioxygenase genes of Mycobacterium sp. comprised 100% of the PAH-RHDα library at the end of the microcosm setup. Moreover, two PAH-degrading Actinobacteria (Arthrobacter sp. and Rhodococcus ruber) were isolated from the original sediment sample and showed high activity in the degradation of phenanthrene and fluorene in liquid cultivation. This study reveals that indigenous bacteria had the ability to degrade high concentrations of mixed PAHs and provide clear evidence that Actinobacteria may be potential candidates to play a major role in PAH degradation in the river sediment.

  12. Bioprospection and selection of bacteria isolated from environments contaminated with petrochemical residues for application in bioremediation.

    Science.gov (United States)

    Cerqueira, Vanessa S; Hollenbach, Emanuel B; Maboni, Franciele; Camargo, Flávio A O; Peralba, Maria do Carmo R; Bento, Fátima M

    2012-03-01

    The use of microorganisms with hydrocarbon degrading capability and biosurfactant producers have emerged as an alternative for sustainable treatment of environmental passives. In this study 45 bacteria were isolated from samples contaminated with petrochemical residues, from which 21 were obtained from Landfarming soil contaminated with oily sludge, 11 were obtained from petrochemical industry effluents and 13 were originated directly from oily sludge. The metabolization capability of different carbon sources, growth capacity and tolerance, biosurfactant production and enzymes detection were determined. A preliminary selection carried out through the analysis of capability for degrading hydrocarbons showed that 22% of the isolates were able to degrade all carbon sources employed. On the other hand, in 36% of the isolates, the degradation of the oily sludge started within 18-48 h. Those isolates were considered as the most efficient ones. Twenty isolates, identified based on partial sequencing of the 16S rRNA gene, were pre-selected. These isolates showed ability for growing in a medium containing 1% of oily sludge as the sole carbon source, tolerance in a medium containing up to 30% of oily sludge, ability for biosurfactant production, and expression of enzymes involved in degradation of aliphatic and aromatic compounds. Five bacteria, identified as Stenotrophomonas acidaminiphila BB5, Bacillus megaterium BB6, Bacillus cibi, Pseudomonas aeruginosa, and Bacillus cereus BS20 were shown to be promising for use as inoculum in bioremediation processes (bioaugmentation) of areas contaminated with petrochemical residues since they can use oily sludge as the sole carbon source and produce biosurfactants.

  13. Combined use of alkane-degrading and plant growth-promoting bacteria enhanced phytoremediation of diesel contaminated soil.

    Science.gov (United States)

    Tara, Nain; Afzal, Muhammad; Ansari, Tariq M; Tahseen, Razia; Iqbal, Samina; Khan, Qaiser M

    2014-01-01

    Inoculation of plants with pollutant-degrading and plant growth-promoting microorganisms is a simple strategy to enhance phytoremediation activity. The objective of this study was to determine the effect of inoculation of different bacterial strains, possessing alkane-degradation and 1-amino-cyclopropane-1 -carboxylic acid (ACC) deaminase activity, on plant growth and phytoremediation activity. Carpet grass (Axonopus affinis) was planted in soil spiked with diesel (1% w/w) for 90 days and inoculated with different bacterial strains, Pseudomonas sp. ITRH25, Pantoea sp. BTRH79 and Burkholderia sp. PsJN, individually and in combination. Generally, bacterial application increased total numbers of culturable hydrocarbon-degrading bacteria in the rhizosphere ofcarpet grass, plant biomass production, hydrocarbon degradation and reduced genotoxicity. Bacterial strains possessing different beneficial traits affect plant growth and phytoremediation activity in different ways. Maximum bacterial population, plant biomass production and hydrocarbon degradation were achieved when carpet grass was inoculated with a consortium of three strains. Enhanced plant biomass production and hydrocarbon degradation were associated with increased numbers of culturable hydrocarbon-degrading bacteria in the rhizosphere of carpet grass. The present study revealed that the combined use of different bacterial strains, exhibiting different beneficial traits, is a highly effective strategy to improve plant growth and phytoremediation activity.

  14. Metagenomic Analysis of Hot Springs in Central India Reveals Hydrocarbon Degrading Thermophiles and Pathways Essential for Survival in Extreme Environments

    Science.gov (United States)

    Saxena, Rituja; Dhakan, Darshan B.; Mittal, Parul; Waiker, Prashant; Chowdhury, Anirban; Ghatak, Arundhuti; Sharma, Vineet K.

    2017-01-01

    Extreme ecosystems such as hot springs are of great interest as a source of novel extremophilic species, enzymes, metabolic functions for survival and biotechnological products. India harbors hundreds of hot springs, the majority of which are not yet explored and require comprehensive studies to unravel their unknown and untapped phylogenetic and functional diversity. The aim of this study was to perform a large-scale metagenomic analysis of three major hot springs located in central India namely, Badi Anhoni, Chhoti Anhoni, and Tattapani at two geographically distinct regions (Anhoni and Tattapani), to uncover the resident microbial community and their metabolic traits. Samples were collected from seven distinct sites of the three hot spring locations with temperature ranging from 43.5 to 98°C. The 16S rRNA gene amplicon sequencing of V3 hypervariable region and shotgun metagenome sequencing uncovered a unique taxonomic and metabolic diversity of the resident thermophilic microbial community in these hot springs. Genes associated with hydrocarbon degradation pathways, such as benzoate, xylene, toluene, and benzene were observed to be abundant in the Anhoni hot springs (43.5–55°C), dominated by Pseudomonas stutzeri and Acidovorax sp., suggesting the presence of chemoorganotrophic thermophilic community with the ability to utilize complex hydrocarbons as a source of energy. A high abundance of genes belonging to methane metabolism pathway was observed at Chhoti Anhoni hot spring, where methane is reported to constitute >80% of all the emitted gases, which was marked by the high abundance of Methylococcus capsulatus. The Tattapani hot spring, with a high-temperature range (61.5–98°C), displayed a lower microbial diversity and was primarily dominated by a nitrate-reducing archaeal species Pyrobaculum aerophilum. A higher abundance of cell metabolism pathways essential for the microbial survival in extreme conditions was observed at Tattapani. Taken together

  15. Bacteria in crude oil survived autoclaving and stimulated differentially by exogenous bacteria.

    Directory of Open Access Journals (Sweden)

    Xiao-Cui Gong

    Full Text Available Autoclaving of crude oil is often used to evaluate the hydrocarbon-degrading abilities of bacteria. This may be potentially useful for bioaugmentation and microbial enhanced oil recovery (MEOR. However, it is not entirely clear if "endogenous" bacteria (e.g., spores in/on crude oil survive the autoclaving process, or influence subsequent evaluation of the hydrocarbon-degradation abilities of the "exogenous" bacterial strains. To test this, we inoculated autoclaved crude oil medium with six exogenous bacterial strains (three Dietzia strains, two Acinetobacter strains, and one Pseudomonas strain. The survival of the spore-forming Bacillus and Paenibacillus and the non-spore-forming mesophilic Pseudomonas, Dietzia, Alcaligenes, and Microbacterium was detected using a 16S rRNA gene clone library and terminal restriction fragment length polymorphism (T-RFLP analysis. However, neither bacteria nor bacterial activity was detected in three controls consisting of non-inoculated autoclaved crude oil medium. These results suggest that detection of endogenous bacteria was stimulated by the six inoculated strains. In addition, inoculation with Acinetobacter spp. stimulated detection of Bacillus, while inoculation with Dietzia spp. and Pseudomonas sp. stimulated the detection of more Pseudomonas. In contrast, similar exogenous bacteria stimulated similar endogenous bacteria at the genus level. Based on these results, special emphasis should be applied to evaluate the influence of bacteria capable of surviving autoclaving on the hydrocarbon-degrading abilities of exogenous bacteria, in particular, with regard to bioaugmentation and MEOR. Bioaugmentation and MEOR technologies could then be developed to more accurately direct the growth of specific endogenous bacteria that may then improve the efficiency of treatment or recovery of crude oil.

  16. [Degradation of L-phenylalanine and of aromatic carboxylic acids by chloridazon-degrading bacteria. Combination of side chain degradation and dioxygenase pathway].

    Science.gov (United States)

    Wegst, W; Lingens, F

    1981-09-01

    Strain N of Chloridazon-degrading bacteria degrades phenylalanine via cis-2,3-dihydro-2,3-dihydroxyphenylalanine,2,3-dihydroxyphenylalanine aspartate and 4-hydroxy-2-oxovalerate [Hoppe-Seyler's Z. Physiol. Chem. 360, 957--969, (1979); Biochem. J. 194, 679--684 (1981)]. cis-2,3-Dihydro-2,3-dihydroxyphenylalanine and 2,3-dihydroxyphenylalanine as well as phenylpyruvate, cis-2,3-dihydro-2,3-dihydroxyphenylpyruvate, 2,3-dihydroxyphenylpyruvate, cis-2,3-dihydro-2,3-dihydroxyphenylacetate, 2,3-dihydroxyphenylacetate and 2,3-dihydroxybenzaldehyde are detectable in the medium of strain E during growth on phenylalanine. Incubation with phenylacetate, 3-phenylpropionate or 4-phenylbutyrate leads to the accumulation of the corresponding cis-2,3-dihydro-2,3-dihydroxyphenyl derivatives. These compounds are transformed with dihydrodiol dehydrogenase to 2,3-dihydroxyphenylacetate, 3-(2,3-dihydroxyphenyl)propionate and 4-(2,3-dihydroxyphenyl)-butyrate, 3-(2,3-dihydroxyphenyl)propionate is attacked by a catechol 2,3-dioxygenase and the meta-cleavage product is again cleaved by a hydrolase yielding succinate. In a similar reaction sequence the degradation of 4-phenylbutyrate leads to the formation of glutarate. From the growth medium of strain E on phenylacetate also small amounts of 2-, 3- and 4-hydroxyphenylacetate were isolated. Resting cells were shown to metabolize 3- and 4-hydroxyphenylacetate via homogentisate and 3,4-dihydroxyphenylacetate. In the culture medium of strain K2AP benzoate could be detected. Pathways for the degradation of phenylalanine and aromatic carboxylic acids in chloridazon degrading bacteria are proposed.

  17. Phytoremediation of Polycyclic Aromatic Hydrocarbons in Soils Artificially Polluted Using Plant-Associated-Endophytic Bacteria and Dactylis glomerata as the Bioremediation Plant.

    Science.gov (United States)

    Gałązka, Ann; Gałązka, Rafał

    2015-01-01

    The reaction of soil microorganisms to the contamination of soil artificially polluted with polycyclic aromatic hydrocarbons (PAHs) was evaluated in pot experiments. The plant used in the tests was cock's foot (Dactylis glomerata). Three different soils artificially contaminated with PAHs were applied in the studies. Three selected PAHs (anthracene, phenanthrene, and pyrene) were used at the doses of 100, 500, and 1000 mg/kg d.m. of soil and diesel fuel at the doses of 100, 500, and 1000 mg/kg d.m. of soil. For evaluation of the synergistic effect of nitrogen fixing bacteria, the following strains were selected: associative Azospirillum spp. and Pseudomonas stutzerii. Additionally, in the bioremediation process, the inoculation of plants with a mixture of the bacterial strains in the amount of 1 ml suspension per 500 g of soil was used. Chamber pot-tests were carried out in controlled conditions during four weeks of plant growth period. The basic physical, microbiological and biochemical properties in contaminated soils were determined. The obtained results showed a statistically important increase in the physical properties of soils polluted with PAHs and diesel fuel compared with the control and also an important decrease in the content of PAHs and heavy metals in soils inoculated with Azospirillum spp. and P. stutzeri after cock's foot grass growth. The bioremediation processes were especially intensive in calcareous rendzina soil artificially polluted with PAHs.

  18. Enrichment of aliphatic, alicyclic and aromatic acids by oil-degrading bacteria isolated from the rhizosphere of plants growing in oil-contaminated soil from Kazakhstan.

    Science.gov (United States)

    Mikolasch, Annett; Omirbekova, Anel; Schumann, Peter; Reinhard, Anne; Sheikhany, Halah; Berzhanova, Ramza; Mukasheva, Togzhan; Schauer, Frieder

    2015-05-01

    Three microbial strains were isolated from the rhizosphere of alfalfa (Medicago sativa), grass mixture (Festuca rubra, 75 %; Lolium perenne, 20 %; Poa pratensis, 10 %), and rape (Brassica napus) on the basis of their high capacity to use crude oil as the sole carbon and energy source. These isolates used an unusually wide spectrum of hydrocarbons as substrates (more than 80), including n-alkanes with chain lengths ranging from C12 to C32, monomethyl- and monoethyl-substituted alkanes (C12-C23), n-alkylcyclo alkanes with alkyl chain lengths from 4 to 18 carbon atoms, as well as substituted monoaromatic and diaromatic hydrocarbons. These three strains were identified as Gordonia rubripertincta and Rhodococcus sp. SBUG 1968. During their transformation of this wide range of hydrocarbon substrates, a very large number of aliphatic, alicyclic, and aromatic acids was detected, 44 of them were identified by GC/MS analyses, and 4 of them are described as metabolites for the first time. Inoculation of plant seeds with these highly potent bacteria had a beneficial effect on shoot and root development of plants which were grown on oil-contaminated sand.

  19. Genome Sequence of Arenibacter algicola Strain TG409, a Hydrocarbon-Degrading Bacterium Associated with Marine Eukaryotic Phytoplankton.

    Science.gov (United States)

    Gutierrez, Tony; Whitman, William B; Huntemann, Marcel; Copeland, Alex; Chen, Amy; Kyrpides, Nikos; Markowitz, Victor; Pillay, Manoj; Ivanova, Natalia; Mikhailova, Natalia; Ovchinnikova, Galina; Andersen, Evan; Pati, Amrita; Stamatis, Dimitrios; Reddy, T B K; Ngan, Chew Yee; Chovatia, Mansi; Daum, Chris; Shapiro, Nicole; Cantor, Michael N; Woyke, Tanja

    2016-08-04

    Arenibacter algicola strain TG409 was isolated from Skeletonema costatum and exhibits the ability to utilize polycyclic aromatic hydrocarbons as sole sources of carbon and energy. Here, we present the genome sequence of this strain, which is 5,550,230 bp with 4,722 genes and an average G+C content of 39.7%.

  20. Hydrocarbon degradation and plant colonization of selected bacterial strains isolated from the rhizsophere and plant interior of Italian ryegrass and Birdsfoot trefoil

    Science.gov (United States)

    Sohail, Y.; Andria, V.; Reichenauer, T. G.; Sessitsch, A.

    2009-04-01

    Hydrocarbon-degrading strains were isolated from the rhizosphere, root and shoot interior of Italian ryegrass (Lolium multiflorum var. Taurus), Birdsfoot trefoil (Lotus corniculatus var. Leo) grown in a soil contaminated with petroleum oil. Strains were tested regarding their phylogeny and their degradation efficiency. The most efficient strains were tested regarding their suitability to be applied for phytoremediation of diesel oils. Sterilized and non-sterilized agricultural soil, with and with out compost, were spiked with diesel and used for planting Italian ryegrass and birdsfoot trefoil. Four selected strains with high degradation activities, derived from the rhizosphere and plant interior, were selected for individual inoculation. Plants were harvested at flowering stage and plant biomass and hydrocarbon degradation was determined. Furthermore, it was investigated to which extent the inoculant strains were able to survive and colonize plants. Microbial community structures were analysed by 16S rRNA and alkB gene analysis. Results showed efficient colonization by the inoculant strains and improved degradation by the application of compost combined with inoculation as well as on microbial community structures will be presented.

  1. Deep Sequencing of Myxilla (Ectyomyxilla) methanophila, an Epibiotic Sponge on Cold-Seep Tubeworms, Reveals Methylotrophic, Thiotrophic, and Putative Hydrocarbon-Degrading Microbial Associations

    KAUST Repository

    Arellano, Shawn M.

    2012-10-11

    The encrusting sponge Myxilla (Ectyomyxilla) methanophila (Poecilosclerida: Myxillidae) is an epibiont on vestimentiferan tubeworms at hydrocarbon seeps on the upper Louisiana slope of the Gulf of Mexico. It has long been suggested that this sponge harbors methylotrophic bacteria due to its low δ13C value and high methanol dehydrogenase activity, yet the full community of microbial associations in M. methanophila remained uncharacterized. In this study, we sequenced 16S rRNA genes representing the microbial community in M. methanophila collected from two hydrocarbon-seep sites (GC234 and Bush Hill) using both Sanger sequencing and next-generation 454 pyrosequencing technologies. Additionally, we compared the microbial community in M. methanophila to that of the biofilm collected from the associated tubeworm. Our results revealed that the microbial diversity in the sponges from both sites was low but the community structure was largely similar, showing a high proportion of methylotrophic bacteria of the genus Methylohalomonas and polycyclic aromatic hydrocarbon (PAH)-degrading bacteria of the genera Cycloclasticus and Neptunomonas. Furthermore, the sponge microbial clone library revealed the dominance of thioautotrophic gammaproteobacterial symbionts in M. methanophila. In contrast, the biofilm communities on the tubeworms were more diverse and dominated by the chemoorganotrophic Moritella at GC234 and methylotrophic Methylomonas and Methylohalomonas at Bush Hill. Overall, our study provides evidence to support previous suggestion that M. methanophila harbors methylotrophic symbionts and also reveals the association of PAH-degrading and thioautotrophic microbes in the sponge. © 2012 Springer Science+Business Media New York.

  2. Kinetics of petroleum hydrocarbon degradation in soil and diversity of microbial community during composting%石油烃类污染物降解动力学和微生物群落多样性分析

    Institute of Scientific and Technical Information of China (English)

    甄丽莎; 谷洁; 胡婷; 刘晨; 贾凤安; 吕睿

    2015-01-01

    为了探讨不同初始浓度石油污染土壤堆腐化修复机制,以石油降解菌剂和腐熟鸡粪为调理剂,研究了初始浓度分别为5000(T1)、10000(T2)和50000 mg/kg(T3)的石油污染土壤堆腐化修复过程石油烃类污染物降解动力学特征和微生物群落多样性。结果表明:堆腐化修复过程石油烃类污染物降解符合一级反应动力学,反应常数分别为0.012、0.094和0.050 d-1,半衰期分别为6.79、7.37和13.86 d。整个堆腐过程石油烃类污染物平均降解速率分别为112.08、230.05和887.93 mg/(kg·d)。3个处理的孔平均颜色变化率(average well color development)和碳源利用率(除芳香烃类化合物外)随堆腐进程的推进逐渐升高,在堆腐中、后期达到最大,T3处理显著高于T1、T2处理。多聚物类和糖类代谢群是堆腐体系中的优势菌群。主成分分析表明3个处理的微生物群落差异显著(除第9天外),起分异作用的碳源主要是糖类和羧酸类。微生物群落的丰富度指数和均一度指数随堆腐进程的推进逐渐升高并在堆腐后期达到最大,与T1处理相比, T3处理分别高了0.21%和17.64%,差异达到显著水平(P0.05)。堆肥结束时3个处理的种子发芽指数(seed germination index, SGI)分别比堆腐初期提高了18.26%、20.42%和36.41%。该研究结果为黄土高原不同程度石油污染土壤堆腐化修复的应用提供参考依据和理论基础。%In order to investigate the mechanism of bioremediation of petroleum hydrocarbon-contaminated soil by composting, an experiment was conducted with bacteria agent and mature chicken manure as amendment. We studied the kinetics of petroleum hydrocarbon degradation and the diversity of microbial community during the bioremediation of petroleum hydrocarbon-contaminated soil by composting with different concentrations. The concentrations included 5 000 mg/kg (T1), 10 000 mg/kg (T2

  3. Diversity of organotrophic bacteria, activity of dehydrogenases and urease as well as seed germination and root growth Lepidium sativum, Sorghum saccharatum and Sinapis alba under the influence of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Lipińska, Aneta; Wyszkowska, Jadwiga; Kucharski, Jan

    2015-12-01

    Polycyclic aromatic hydrocarbons are organic compounds with highly toxic, carcinogenic, and mutagenic properties, which adversely affect the basic biological parameters of the soil, including the count of microorganisms, and the enzymatic activity. In addition to disturbances to the biological activity of the soil, PAHs may also exhibit toxic effects on plants. In view of the above, the study involved testing aimed at the determination of the effects of polycyclic aromatic hydrocarbons in a form of naphthalene, phenanthrene, anthracene and pyrene on the count, colony development (CD) index, ecophysiological (EP) diversity index of organotrophic bacteria, and the activity of soil dehydrogenases and soil urease. Moreover, an attempt was made to determine the soil's resistance based on the activity of the above-listed enzymes, and the effect of polycyclic aromatic hydrocarbons on seed germination and root growth was assessed by Lepidium sativum, Sorghum saccharatum, and Sinapis alba. In addition, the species of bacteria found in a soil subjected to strong pressure of polycyclic aromatic hydrocarbons were isolated. The experiment was performed in a laboratory on samples of loamy sand. Polycyclic aromatic hydrocarbons were introduced into the soil in an amount of 0, 1000, 2000, and 4000 mg kg(-1) of soil dry matter. Germination and growth of cress (L. sativum), white mustard (S. alba), and sweet sorghum (S. saccharatum) were determined using Phytotoxkit tests. It was found that the tested PAHs increased the average colony counts of organotrophic soil bacteria; pyrene did so to the greatest extent (2.2-fold relative to non-contaminated soil), phenanthrene to the smallest extent (1.4-fold relative to non-contaminated soil). None of the PAHs changed the value of the bacterial colony development (CD) index, while anthracene and pyrene increased the value of the eco-physiological (EP) diversity indicator. PAHs lowered the activity of the tested enzymes. The activity of

  4. Microbial diversity and hydrocarbon degrading gene capacity of a crude oil field soil as determined by metagenomics analysis.

    Science.gov (United States)

    Abbasian, Firouz; Palanisami, Thavamani; Megharaj, Mallavarapu; Naidu, Ravi; Lockington, Robin; Ramadass, Kavitha

    2016-05-01

    Soils contaminated with crude oil are rich sources of enzymes suitable for both degradation of hydrocarbons through bioremediation processes and improvement of crude oil during its refining steps. Due to the long term selection, crude oil fields are unique environments for the identification of microorganisms with the ability to produce these enzymes. In this metagenomic study, based on Hiseq Illumina sequencing of samples obtained from a crude oil field and analysis of data on MG-RAST, Actinomycetales (9.8%) were found to be the dominant microorganisms, followed by Rhizobiales (3.3%). Furthermore, several functional genes were found in this study, mostly belong to Actinobacteria (12.35%), which have a role in the metabolism of aliphatic and aromatic hydrocarbons (2.51%), desulfurization (0.03%), element shortage (5.6%), and resistance to heavy metals (1.1%). This information will be useful for assisting in the application of microorganisms in the removal of hydrocarbon contamination and/or for improving the quality of crude oil. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:638-648, 2016.

  5. Bacterial degradation of monocyclic aromatic amines

    Directory of Open Access Journals (Sweden)

    Pankaj Kumar Arora

    2015-08-01

    Full Text Available Aromatic amines are an important group of industrial chemicals, which are widely used for manufacturing of dyes, pesticides, drugs, pigments, and other industrial products. These compounds have been considered highly toxic to human beings due to their carcinogenic nature. Three groups of aromatic amines have been recognized: monocyclic, polycyclic and heterocyclic aromatic amines. Bacterial degradation of several monocyclic aromatic compounds has been studied in a variety of bacteria, which utilizes monocyclic aromatic amines as their sole source of carbon and energy. Several degradation pathways have been proposed and the related enzymes and genes have also been characterized. Many reviews have been reviewed toxicity of monocyclic aromatic amines; however, there is lack of review on biodegradation of monocyclic aromatic amines. The aim of this review is to summarize bacterial degradation of monocyclic aromatic amines. This review will increase our current understanding of biochemical and molecular basis of bacterial degradation of monocyclic aromatic amines.

  6. Soil microbial toxicity of eight polycyclic aromatic compounds: effects on nitrification, the genetic diversity of bacteria, and the total number of protozoans

    DEFF Research Database (Denmark)

    Sverdrup, Line Emilie; Ekelund, Flemming; Krogh, Paul Henning;

    2002-01-01

    Eight polycyclic aromatic compounds (PACs) were tested for their toxic effect on the soil nitrification process, bacterial genetic diversity, and the total number of protozoans (naked amoebae and heterotrophic flagellates). After four weeks of exposure in a well-characterized agricultural soil...

  7. Bacteria and lignin degradation

    Institute of Scientific and Technical Information of China (English)

    Jing LI; Hongli YUAN; Jinshui YANG

    2009-01-01

    Lignin is both the most abundant aromatic (phenolic) polymer and the second most abundant raw material.It is degraded and modified by bacteria in the natural world,and bacteria seem to play a leading role in decomposing lignin in aquatic ecosystems.Lignin-degrading bacteria approach the polymer by mechanisms such as tunneling,erosion,and cavitation.With the advantages of immense environmental adaptability and biochemical versatility,bacteria deserve to be studied for their ligninolytic potential.

  8. Ecological and aromatic impact of two Gram-negative bacteria (Psychrobacter celer and Hafnia alvei) inoculated as part of the whole microbial community of an experimental smear soft cheese.

    Science.gov (United States)

    Irlinger, Françoise; Yung, Stéphane Ah Yuen In; Sarthou, Anne-Sophie; Delbès-Paus, Céline; Montel, Marie-Christine; Coton, Emmanuel; Coton, Monika; Helinck, Sandra

    2012-02-15

    The impact of the growth of two Gram-negative bacteria, Psychrobacter celer and Hafnia alvei, inoculated at 10(2) and 10(6) cfu/g, on the dynamics of a multispecies community as well as on volatile aroma compound production during cheese ripening was investigated. Results showed that P. celer was able to successfully implant itself in cheese, regardless of its inoculation level. However, when it was inoculated at a high level, the bacterial biodiversity was drastically lowered from day 25 to the end of ripening. Overall, the presence of P. celer led to the higher production of volatile aroma compounds such as aldehydes, ketones and sulfur compounds. Regardless of its inoculation level, H. alvei barely affected the growth of the bacterial community and was subdominant at the end of ripening. It influenced total volatile aroma compound production with volatile sulfur compounds being the most abundant. Overall, these two bacteria were able to implant themselves in a cheese community and significantly contributed to the aromatic properties of the cheese. Their role in flavoring and their interactions with the technological microorganisms must be considered during cheese ripening and should be further investigated.

  9. Bacteria associated with arbuscular mycorrhizal fungi within roots of plants growing in a soil highly contaminated with aliphatic and aromatic petroleum hydrocarbons.

    Science.gov (United States)

    Iffis, Bachir; St-Arnaud, Marc; Hijri, Mohamed

    2014-09-01

    Arbuscular mycorrhizal fungi (AMF) belong to phylum Glomeromycota, an early divergent fungal lineage forming symbiosis with plant roots. Many reports have documented that bacteria are intimately associated with AMF mycelia in the soil. However, the role of these bacteria remains unclear and their diversity within intraradical AMF structures has yet to be explored. We aim to assess the bacterial communities associated within intraradical propagules (vesicles and intraradical spores) harvested from roots of plant growing in the sediments of an extremely petroleum hydrocarbon-polluted basin. Solidago rugosa roots were sampled, surface-sterilized, and microdissected. Eleven propagules were randomly collected and individually subjected to whole-genome amplification, followed by PCRs, cloning, and sequencing targeting fungal and bacterial rDNA. Ribotyping of the 11 propagules showed that at least five different AMF OTUs could be present in S. rugosa roots, while 16S rRNA ribotyping of six of the 11 different propagules showed a surprisingly high bacterial richness associated with the AMF within plant roots. Most dominant bacterial OTUs belonged to Sphingomonas sp., Pseudomonas sp., Massilia sp., and Methylobacterium sp. This study provides the first evidence of the bacterial diversity associated with AMF propagules within the roots of plants growing in extremely petroleum hydrocarbon-polluted conditions.

  10. Aromatic graphene

    Science.gov (United States)

    Das, D. K.; Sahoo, S.

    2016-04-01

    In recent years graphene attracts the scientific and engineering communities due to its outstanding electronic, thermal, mechanical and optical properties and many potential applications. Recently, Popov et al. [1] have studied the properties of graphene and proved that it is aromatic but without fragrance. In this paper, we present a theory to prepare graphene with fragrance. This can be used as scented pencils, perfumes, room and car fresheners, cosmetics and many other useful household substances.

  11. Dehalogenation of aromatics by nucleophilic aromatic substitution.

    Science.gov (United States)

    Sadowsky, Daniel; McNeill, Kristopher; Cramer, Christopher J

    2014-09-16

    Nucleophilic aromatic substitution has been implicated as a mechanism for both the biotic and abiotic hydrodehalogenation of aromatics. Two mechanisms for the aqueous dehalogenation of aromatics involving nucleophilic aromatic substitution with hydride as a nucleophile are investigated using a validated density functional and continuum solvation protocol. For chlorinated and brominated aromatics, nucleophilic addition ortho to carbon-halogen bonds via an anionic intermediate is predicted to be the preferred mechanism in the majority of cases, while concerted substitution is predicted to be preferred for most fluorinated aromatics. Nucleophilic aromatic substitution reactions with the hydroxide and hydrosulfide anions as nucleophiles are also investigated and compared.

  12. 利用绿色荧光蛋白标记革兰氏阴性细菌的研究%Labeling gram-negative bacteria using green fluorescent protein

    Institute of Scientific and Technical Information of China (English)

    崔长征; 沈萍; 张甲耀; 冯耀宇; 林匡飞

    2011-01-01

    In this study, four transposable plasmids were constructed, pTnMod-OCm-G, pTnMod-OTc-G, pTnMod-OKm3-G and pTnMod-OGm-G, which can constitutively express green fluorescent protein. Via triparental mating, the GFP gene was inserted into genomes of Sphingomonas sp. 12A and Pseudomonas sp. 12B, two polycyclic aromatic hydrocarbons-degrading bacterial strains. The transformants, which can degrade polycyclic aromatic hydrocarbons, can constitutively express GFP without the presence of antibiotics through many generations of propagation. The transposons can be transferred to other gram negative bacteria and expressed stably. Therefore, they have potential to be used in research on bacterial survival and ecological safety in contaminated environments.%构建了具有不同抗性且能够组成型表达绿色荧光蛋白的一系列转座子质粒pTnMod-OCm-G、pTnMod-OTc-G、pTnMod-OKm3-G和pTnMod-OGm-G,并通过三亲本杂交的方法,成功地将荧光蛋白基因分别插入到多环芳烃降解菌株Sphingomonas sp.12A和Pseudomonas sp.12B的基因组内,获得了具有降解多环芳烃特性,同时在没有抗生素选择压力下连续传代多次仍能够稳定组成型表达荧光的转化子.结果表明,该系列转座子不仅适合其它革兰氏阴性菌的遗传标记,也为进一步研究降解菌在污染环境中的存活能力和生态安全奠定了基础.

  13. Removal of crude oil polycyclic aromatic hydrocarbons via organoclay-microbe-oil interactions.

    Science.gov (United States)

    Ugochukwu, Uzochukwu C; Fialips, Claire I

    2017-05-01

    Clay minerals are quite vital in biogeochemical processes but the effect of organo-clays in the microbial degradation of crude oil polycyclic aromatic hydrocarbons is not well understood. The role of organo-saponite and organo-montmorillonite in comparison with the unmodified clays in crude oil polycyclic aromatic hydrocarbons (PAHs) removal via adsorption and biodegradation was studied by carrying out microcosm experiments in aqueous clay/oil systems with a hydrocarbon degrading microbial community that is predominantly alcanivorax spp. Montmorillonite and saponite samples were treated with didecyldimethylammonium bromide to produce organo-montmorillonite and organo-saponite used in this study. Obtained results indicate that clays with high cation exchange capacity (CEC) such as montmorillonite produced organo-clay (organomontmorillonite) that was not stimulatory to biodegradation of crude oil polycyclic aromatic compounds, especially the low molecular weight (LMW) ones, such as dimethylnaphthalenes. It is suggested that interaction between the organic phase of the organo-clay and the crude oil PAHs which is hydrophobic in nature must have reduced the availability of the polycyclic aromatic hydrocarbons for biodegradation. Organo-saponite did not enhance the microbial degradation of dimethylnaphthalenes but enhanced the biodegradation of some other PAHs such as phenanthrene. The unmodified montmorillonite enhanced the microbial degradation of the PAHs and is most likely to have done so as a result of its high surface area that allows the accumulation of microbes and nutrients enhancing their contact.

  14. Effect of interlayer cations of montmorillonite on the biodegradation and adsorption of crude oil polycyclic aromatic compounds.

    Science.gov (United States)

    Ugochukwu, Uzochukwu C; Manning, David A C; Fialips, Claire I

    2014-09-01

    Cation exchange capacity, surface acidity and specific surface area are surface properties of clay minerals that make them act as catalysts or supports in most biogeochemical processes hence making them play important roles in environmental control. However, the role of homoionic clay minerals during the biodegradation of polycyclic aromatic compounds is not well reported. In this study, the effect of interlayer cations of montmorillonites in the removal of some crude oil polycyclic aromatic compounds during biodegradation was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. The homoionic montmorillonites were prepared via cation exchange reactions by treating the unmodified montmorillonite with the relevant metallic chloride. The study indicated that potassium-montmorillonite and zinc-montmorillonite did not enhance the biodegradation of the polycyclic aromatic hydrocarbons whereas calcium-montmorillonite, and ferric-montmorillonite enhanced their biodegradation significantly. Adsorption of polycyclic aromatic hydrocarbons was significant during biodegradation with potassium- and zinc-montmorillonite where there was about 45% removal of the polycyclic aromatic compounds by adsorption in the experimental microcosm containing 5:1 ratio (w/w) of clay to oil.

  15. [Inhibition of aromatics on ammonia-oxidizing activity of sediment].

    Science.gov (United States)

    Dong, Chun-hong; Hu, Hong-ying; Wei, Dong-bin; Huang, Xia; Qian, Yi

    2004-03-01

    The inhibition of 24 aromatics on ammonia-oxidizing activity of nitrifying bacteria in sediment was measured. The effects of the kind, number and position of substituted groups on ammonia-oxidizing activity of nitrifying bacteria were discussed. The inhibition of mono-substituted benzenes on ammonia-oxidizing activity of nitrifying bacteria were in order of -OH > -NO2 > -NH2 > -Cl > -CH3 > -H. The position of substituted groups of di-substituted benzenes also affected the inhibition, and the inhibitions of dimethylbenzenes(xylene) were in order of meta-> ortho-> para-. The increase in number of substituted group on benzene-ring enhanced the inhibition of aromatics studied in this study on nitrifying bacteria. There was a linear relationship between inhibition (IC50, mumol.L-1) of aromatics on ammonia-oxidizing activity and total electronegativity (sigma E) of aromatics: lgIC50 = 14.72 - 0.91 sigma E.

  16. Total Phosphate Influences the Rate of Hydrocarbon Degradation but Phosphate Mineralogy Shapes Microbial Community Composition in Cold-Region Calcareous Soils.

    Science.gov (United States)

    Siciliano, Steven D; Chen, Tingting; Phillips, Courtney; Hamilton, Jordan; Hilger, David; Chartrand, Blaine; Grosskleg, Jay; Bradshaw, Kris; Carlson, Trevor; Peak, Derek

    2016-05-17

    Managing phosphorus bioaccessibility is critical for the bioremediation of hydrocarbons in calcareous soils. This paper explores how soil mineralogy interacts with a novel biostimulatory solution to both control phosphorus bioavailability and influence bioremediation. Two large bore infiltrators (1 m diameter) were installed at a PHC contaminated site and continuously supplied with a solution containing nutrients and an electron acceptor. Soils from eight contaminated sites were prepared and pretreated, analyzed pretrial, spiked with diesel, placed into nylon bags into the infiltrators, and removed after 3 months. From XAS, we learned that three principal phosphate phases had formed: adsorbed phosphate, brushite, and newberyite. All measures of biodegradation in the samples (in situ degradation estimates, mineralization assays, culturable bacteria, catabolic genes) varied depending upon the soil's phosphate speciation. Notably, adsorbed phosphate increased anaerobic phenanthrene degradation and bzdN catabolic gene prevalence. The dominant mineralogical constraints on community composition were the relative amounts of adsorbed phosphate, brushite, and newberyite. Overall, this study finds that total phosphate influences microbial community phenotypes whereas relative percentages of phosphate minerals influences microbial community genotype composition.

  17. 芳香植物源营养液对梨树的抑菌和营养效应%Effect of Aromatic Plant-Derived Nutrient Solution on Inhibition of Harmful Bacteria and Nutrition for Pear Plants

    Institute of Scientific and Technical Information of China (English)

    刘艳娜; 崔楠楠; 张杰; 于凤鸣; 张立彬; 姚允聪

    2011-01-01

    proportional mixture (Tr6), respectively. And bio-bacterial manure Nanguochun, a kind of foliar fertilizers (Tr7), and water (Tr8) were used as control. [Result] The results indicated that the foliar application of aromatic plant-derived nutrient solution and indoor antimicrobial tests was good in bacteriostatic effect of Venturia pirina Aderh, Pnysalospora pinicola Nose and Valisa mali and their anti-bacteria effect respectively reached 76.00%, 82.12%, 87.88% compared with controls. The foliar application of both plant-derived nutrient solutions and Nanguochun promoted the growth of shoots, increased the leaf area and improved the contents of mineral elements in leaves except for element P. In terms of comparison of the effects among different treatments, spraying Tr3 largely improved the growth of pear plants Pyrus pyrifolia (Burm. F.) Nakai/ Pyrus betulaefolia Bunge. [Conclusion] It is suggested that foliar application of plant-derived nutrient solution couldresult in improving the nutrient contents in leaves of trees and the status of nutrition growth, and simultaneously play a role in preventions of Venturia pirina Aderh, Pnysalospora pinicola Nose and Valisa malt in leaves of pear plants.

  18. Application of fluorescent antibody and enzyme-linked immunosorbent assays for TCE and PAH degrading bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R.L.; Franck, M.; Brey, J.; Scott, D.; Lanclos, K.; Fliermans, C.

    1996-07-01

    Historically, methods used to identify methanotrophic and polyaromatic hydrocarbon-degrading (PAH) bacteria in environmental samples have been inadequate because isolation and identification procedures are time-consuming and often fail to separate specific bacteria from other environmental microorganisms. Methanotrophic bacteria have been isolated and characterized from TCE-contaminated soils (Bowman et al. 1993; Fliermans et al., 1988). Fliermans et al., (1988) and others demonstrated that cultures enriched with methane and propane could cometabolically degrade a wide variety of chlorinated aliphatic hydrocarbons including ethylene; 1,2-cisdichloroethylene (c-DCE); 1,2-trans-dichloroethylene (t-DCE); vinyl chloride (VC); toluene; phenol and cresol. Characterization of select microorganisms in the natural setting is important for the evaluation of bioremediation potential and its effectiveness. This realization has necessitated techniques that are selective, sensitive and easily applicable to soils, sediments, and groundwater (Fliermans, et al., 1994). Additionally these techniques can identify and quantify microbial types in situ in real time

  19. In-situ sanitation of hydrocarbon polluted soils. Vol. 2. Subordinate project: Microbial studies on hydrocarbon degradation. Final report; In-Situ-Sanierung kohlenwasserstoffbelasteter Boeden. Bd. 2. Teilprojekt: Mikrobiologische Untersuchungen zum Kohlenwasserstoffabbau. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Pommeranz, S.; Boldrin, B.; Tiehm, A.; Zipperle, J.; Fritzsche, C.; Zumft, W.

    1993-09-01

    One aim of the subproject at the department of microbiology was to identify microorganisms capable of degrading components of soil pollutants typically emitted by gas works. Binuclear, trinuclear, and tetranuclear polycyclic aromatic hydrocarbons (PAH) were used as test substances, namely naphthaliene, phenanthrene, fluorene, anthracene, fluoranthene, and pyrene. The results show that there are numerous and diverse competent microbial species in the soil of the gas works premises in the east of Karlsruhe. Of the 23 soil samples examined 20 contained PAH degrading microorganisms. Of the 355 isolates tested individually 168 degraded naphthalene, 34 enthracene, 37 fluorene, 25 fluoranthene, and 5 pyrene. Competent pure and mixed cultures were isolated for each of the model substances used. This shows that the antochtonous populations have adapted to the conditions after the accident and that the soil contains PAH degrading microorganisms (70% of isolates in a sample). The PAH degrading bacteria belong to different species: many were identified as pseudomonas sp., but alcaligues sp., acinetobacter sp. and myobacterium sp. were also found. (orig./EF) [Deutsch] Ein Schwerpunkt des Teilprojektes am Lehrstuhl fuer Mikrobiologie war die Erfassung der Mikroorganismen, die Komponenten von gaswerksspezifischen Bodenkontaminationen abbauen koennen. Als Leitsubstanzen wurden die 2-, 3-, und 4-kernigen polyzyklischen aromatischen Kohlenwasserstoffe (PAK) Naphthalin, Phenanthren, Fluoren, Anthracen, Fluoranthen und Pyren ausgewaehlt. Die Ergebnisse zeigen deutlich die hohe Anzahl und Diversitaet kompetenter Mikroorganismen im Boden des ehemaligen Gaswerksgelaendes Karlsruhe-Ost. Insgesamt wurden in 20 von 23 untersuchten Bodenproben PAK-verwertende Mikroorganismen nachgewiesen. Von 355 einzeln getesteten Isolaten verwerteten 168 Naphthalin, 163 Phenanthren, 34 Anthracen, 37 Fluoren, 25 Fluoranthen und 5 Pyren. Fuer jede verwendete Modellsubstanz wurden kompetente Misch- und

  20. 低能离子诱变烃降解菌所产表面活性剂的研究%Surfactant Produced by Hydrocarbon Degrading Bacteria Mutated with Low Energy Ion

    Institute of Scientific and Technical Information of China (English)

    向廷生; 郭晓博; 张祥胜

    2013-01-01

    菌株产表面活性剂的能力直接影响其对石油烃的降解和利用,大量的研究表明,生物表面活性剂可以通过胶束来渗透、润湿、乳化、增溶、发泡、消泡等作用促进石油的利用,有效提高石油烃的降解,加快油污土壤的生物修复过程.对菌株23产表面活性剂和菌株生长的关系,发酵液中表面活性剂的提取鉴定,以及生物表面活性剂的临界胶束浓度,对温度、pH、盐度的稳定性,对石蜡的乳化活性等理化性质进行了初步分析研究,为该菌株进一步的研究以及今后实际应用提供较多的资料和信息,为其应用领域提供理论依据,以便更好的发挥其在实际生产中的功能.%The ability of surfactant produced by strains directly affects its degradation and utilization of petroleum hydrocarbons , much of study showed that the biosurfactants could permeate through the micelle, wetting, emulsification, solubilization, foaming, and defoaming actions to promote the use of petroleum, effectively improve the degradation of petroleum hydrocarbons, and to speed up the oil-spilled soil bioremediation process. The relationship between the production of surfactant and the growth of strain 23, the extraction and identification of the surfactant in the fermentation broth, as well as bio-surfactant critical micelle concentration, the stability to temperature, pH, salinity, paraffin e-mulsificalion activity and other physical and chemical properties were preliminarily analyzed and studied in this paper; more data and information of this strain were provided for further studies and practical applications, and provide theoretical basis in their applications fields, in order to play their function in the actual production better.

  1. 海洋石油烃降解细菌T1和T2的分子鉴定分类%Molecular identification and classification of marine hydrocarbon degrading bacteria T1 and T2

    Institute of Scientific and Technical Information of China (English)

    田胜艳; 王娟; 聂利红

    2008-01-01

    从天津滨海潮间带被石油烃严重污染的沉积物(干样含油量0.2 g/g)中,筛选分离出能够以柴油为唯一碳源生长的细菌,对其中生物量大、单株菌降解效率较高的两株细菌T1和T2进行16S rDNA克隆,通过测定和比较16S rDNA的部分序列对这两株细菌进行分子鉴定,以期用于石油污染的微生物修复中.结果表明,T1与深红红螺菌(Rhodospirillum rubrum)的同源性为89%,T2与施氏甲单孢杆菌(Pseudomonas stutzeri)的同源性为99%.

  2. 南极石油烃降解嗜冷菌的筛选及其降解特性的研究%Study on Screening of Antarctic Psychrophilic Bacteria for Petroleum Hydrocarbon Degradation and Their Degrading Characteristics

    Institute of Scientific and Technical Information of China (English)

    郑洲; 刘芳明; 张波涛; 徐庆龙; 缪锦来

    2007-01-01

    从385株南极海洋细菌中筛选出2株石油烃降解菌NJ276和NJ341,并对其降解特性进行了初步研究.以柴油为唯一碳源进行降解实验的结果表明,它们在5 ℃时20 d内对柴油的降解率分别达到23.47%和32.15%,在15 ℃时20 d内降解率分别达到43.95%和62.47%,其降解能力随着培养温度的升高而显著增强;石油烃降解残油组分的GC-MS分析结果表明,柴油经过嗜冷菌NJ276降解后的残油组分中能检测到C15~C21 七种烷烃,经过嗜冷菌NJ341降解后的残油组分只能检测到少量C16,C17和C18 三种烷烃.对它们进行16S rDNA 基因序列的同源性和系统发育分析结果表明,菌株NJ276属于假交替单胞菌属(Pseudoalteromonas),菌株NJ341 属于科尔韦尔氏属(Colwellia).

  3. Diversity of alkane degrading bacteria associated with plants in a petroleum oil-contaminated environment and expression of alkane monooxygenase (alkB) genes

    Science.gov (United States)

    Andria, V.; Yousaf, S.; Reichenauer, T. G.; Smalla, K.; Sessitsch, A.

    2009-04-01

    Among twenty-six different plant species, Italian ryegrass (Lolium multiflorum var. Taurus), Birdsfoot trefoil (Lotus corniculatus var. Leo), and the combination of both plants performed well in a petroleum oil contaminated soil. Hydrocarbon degrading bacteria were isolated from the rhizosphere, root interior and shoot interior and subjected to the analysis of 16S rRNA, the 16S and 23S rRNA intergenic spacer region and alkane hydroxylase genes. Higher numbers of culturable, degrading bacteria were associated with Italian ryegrass, which were also characterized by a higher diversity, particularly in the plant interior. Only half of the isolated bacteria hosted known alkane hydroxylase genes (alkB and cytochrome P153-like). Our results indicated that alkB genes have spread through horizontal gene transfer, particularly in the Italian ryegrass rhizosphere, and suggested mobility of catabolic genes between Gram-negative and Gram-positive bacteria. We furthermore studied the colonization behaviour of selected hydrocarbon-degrading strains (comprising an endopyhte and a rhizosphere strain) as well as the expression of their alkane monooxygenase genes in association with Italian ryegrass. Results showed that the endophyte strain better colonized the plant, particularly the plant interior, and also showed higher expression of alkB genes suggesting a more efficient degradation of the pollutant. Furthermore, plants inoculated with the endophyte were better able to grow in the presence of diesel. The rhizosphere strain colonized primarily the rhizosphere and showed low alkB gene expression in the plant interior.

  4. Prenyl transfer to aromatic substrates: genetics and enzymology.

    Science.gov (United States)

    Heide, Lutz

    2009-04-01

    Aromatic prenyltransferases catalyze the transfer of prenyl moieties to aromatic acceptor molecules and give rise to an astounding diversity of primary and secondary metabolites in plants, fungi and bacteria. Significant progress has been made in the biochemistry and genetics of this heterogeneous group of enzymes in the past years. After 30 years of extensive research on plant prenylflavonoid biosynthesis, finally the first aromatic prenyltransferases involved in the formation of these compounds have been cloned. In bacteria, investigations of the newly discovered family of ABBA prenyltransferases revealed a novel type of protein fold, the PT barrel. In fungi, a group of closely related indole prenyltransferase was found to carry out aromatic prenylations with different substrate specificity and regiospecificity, and to catalyze both regular and reverse prenylations.

  5. Hydrocarbons degrading yeasts from Cochin backwater

    Digital Repository Service at National Institute of Oceanography (India)

    Prabhakaran, N.; Sivadas, P

    stream_size 5 stream_content_type text/plain stream_name J_Mar_Biol_Assoc_India_37_226.pdf.txt stream_source_info J_Mar_Biol_Assoc_India_37_226.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  6. Aromater i drikkevand

    DEFF Research Database (Denmark)

    Nyeland, B. A.; Hansen, A. B.

    DMU har den 10. Juni 1997 afholdt en præstationsprøvning: Aromater i drikkevand. Der deltog 21 laboratorier i præstationsprøvningen. Prøvningen omfattede 6 vandige prøver og 6 ampuller indeholdende 6 aromater. Laboratorierne spikede de tilsendte vandprøver med indholdet fra ampullerne...

  7. Identification and characterization of a novel hydrocarbon-degrading Marinobacter sp.PY97S%一株石油烃降解菌新种Marinobacter sp.PY97S的鉴定

    Institute of Scientific and Technical Information of China (English)

    李倩; 崔志松; 赵爱芬; 高伟; 郑立

    2011-01-01

    [目的]为了对1株从黄海沉积物中分离到的石油烃降解菌新种PY97S进行分类学鉴定.[方法]采用16S rRNA基因序列同源性分析、生理生化指标测定、抗生素抗性实验,DNA G+C含量测定、全细胞脂肪酸组成测定、碳源利用实验、呼吸醒测定以及DNA杂交实验等多种方法对该菌株进行鉴定,并通过降解实验测定其对烷烃的利用情况.[结果]菌株PY97S为海杆菌(Marinobacter),革兰氏阴性,接触酶阳性,氧化酶阳性,主要呼吸醌为Q-9.在GenBank中与其16S rRNA基因序列相似度最高的模式株为Marinobacter koreensisDD-M3T(96.93%),两者DNA-DNA同源性仅为46.7%.菌株PY97S的温度生长范围为15℃-35℃(最适为30℃),NaCl浓度生长范围是0-10%(最适为0%),初始pH生长范围为pH 6.0-9.0(最适为初始pH7.0).该菌株可以利用多种糖类和有机酸类的碳源,并对氨苄青霉素、氧哌嗪青霉素等多种抗生素敏感.其DNA G+C含量为48.2 mol%.其主要脂肪酸组成为2-methyl C15∶0(29.97%)、C16∶1ω7c(27.22%)、C12∶0(22.22%)和C16∶1ω9c(5.73%).[结论]菌株PY97S是1株能够降解多种多环芳烃和烷烃的海洋石油烃降解菌新种,具有应用到溢油污染海洋环境生物修复的潜力.%[Objective]To identify and characterize a hydrocarbon-degrading bacterium isolated from the sediment of the Yellow Sea.[Methods]We used 16S rRNA gene sequences based phylogenetic analysis, physiological and biochemical characterization, DNA G + C content assaying, determination of cellular fatty acids, testing of carbon sources and respiratory lipoquinone and experiment of DNA-DNA relatedness.Its capability of degrading aliphatic hydrocarbons in 0NR7a media supplemented with nine n-alkanes, separately, as sole source of carbon and energy was further determined.[Results]The Gram-negative isolate PY97S was a member of the genus Marinobacter, catalase-and oxidase-positive, and with Q-9 as its predominant respiratory lipoquinone

  8. Anaerobic catabolism of aromatic compounds: a genetic and genomic view.

    Science.gov (United States)

    Carmona, Manuel; Zamarro, María Teresa; Blázquez, Blas; Durante-Rodríguez, Gonzalo; Juárez, Javier F; Valderrama, J Andrés; Barragán, María J L; García, José Luis; Díaz, Eduardo

    2009-03-01

    Aromatic compounds belong to one of the most widely distributed classes of organic compounds in nature, and a significant number of xenobiotics belong to this family of compounds. Since many habitats containing large amounts of aromatic compounds are often anoxic, the anaerobic catabolism of aromatic compounds by microorganisms becomes crucial in biogeochemical cycles and in the sustainable development of the biosphere. The mineralization of aromatic compounds by facultative or obligate anaerobic bacteria can be coupled to anaerobic respiration with a variety of electron acceptors as well as to fermentation and anoxygenic photosynthesis. Since the redox potential of the electron-accepting system dictates the degradative strategy, there is wide biochemical diversity among anaerobic aromatic degraders. However, the genetic determinants of all these processes and the mechanisms involved in their regulation are much less studied. This review focuses on the recent findings that standard molecular biology approaches together with new high-throughput technologies (e.g., genome sequencing, transcriptomics, proteomics, and metagenomics) have provided regarding the genetics, regulation, ecophysiology, and evolution of anaerobic aromatic degradation pathways. These studies revealed that the anaerobic catabolism of aromatic compounds is more diverse and widespread than previously thought, and the complex metabolic and stress programs associated with the use of aromatic compounds under anaerobic conditions are starting to be unraveled. Anaerobic biotransformation processes based on unprecedented enzymes and pathways with novel metabolic capabilities, as well as the design of novel regulatory circuits and catabolic networks of great biotechnological potential in synthetic biology, are now feasible to approach.

  9. Evaluating the biodegradation of aromatic hydrocarbons by monitoring of several functional genes.

    Science.gov (United States)

    Piskonen, Reetta; Nyyssönen, Mari; Itävaara, Merja

    2008-11-01

    Various microbial activities determine the effectiveness of bioremediation processes. In this work, we evaluated the feasibility of gene array hybridization for monitoring the efficiency of biodegradation processes. Biodegradation of 14C-labelled naphthalene and toluene by the aromatic hydrocarbon-degrading Pseudomonas putida F1, P. putida mt-2 and P. putida G7 was followed in mixed liquid culture microcosm by a preliminary, nylon membrane-based gene array. In the beginning of the study, toluene was degraded rapidly and increased amount of toluene degradation genes was detected by the preliminary gene array developed for the study. After toluene was degraded, naphthalene mineralization started and the amount of naphthalene degradation genes increased as biodegradation proceeded. The amount of toluene degradation genes decreased towards the end of the study. The hybridization signal intensities determined by preliminary gene array were in good agreement with mineralization of naphthalene and toluene and with the amount of naphthalene dioxygenase and toluene dioxygenase genes quantified by dot blot hybridization. The clear correlation between the results obtained by the preliminary array and the biodegradation process suggests that gene array methods can be considered as a promising tool for monitoring the efficiency of biodegradation processes.

  10. Biodegradation of polycyclic aromatic hydrocarbons by Trichoderma species: a mini review.

    Science.gov (United States)

    Zafra, German; Cortés-Espinosa, Diana V

    2015-12-01

    Fungi belonging to Trichoderma genus are ascomycetes found in soils worldwide. Trichoderma has been studied in relation to diverse biotechnological applications and are known as successful colonizers of their common habitats. Members of this genus have been well described as effective biocontrol organisms through the production of secondary metabolites with potential applications as new antibiotics. Even though members of Trichoderma are commonly used for the commercial production of lytic enzymes, as a biological control agent, and also in the food industry, their use in xenobiotic biodegradation is limited. Trichoderma stands out as a genus with a great range of substrate utilization, a high production of antimicrobial compounds, and its ability for environmental opportunism. In this review, we focused on the recent advances in the research of Trichoderma species as potent and efficient aromatic hydrocarbon-degrading organisms, as well as aimed to provide insight into its potential role in the bioremediation of soils contaminated with heavy hydrocarbons. Several Trichoderma species are associated with the ability to metabolize a variety of both high and low molecular weight polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, phenanthrene, chrysene, pyrene, and benzo[a]pyrene. PAH-degrading species include Trichoderma hamatum, Trichoderma harzianum, Trichoderma reesei, Trichoderma koningii, Trichoderma viride, Trichoderma virens, and Trichoderma asperellum using alternate enzyme systems commonly seen in other organisms, such as multicooper laccases, peroxidases, and ring-cleavage dioxygenases. Within these species, T. asperellum stands out as a versatile organism with remarkable degrading abilities, high tolerance, and a remarkable potential to be used as a remediation agent in polluted soils.

  11. Biodegradation of Aromatic Hydrocarbons in an Extremely Acidic Environment

    Science.gov (United States)

    Stapleton, Raymond D.; Savage, Dwayne C.; Sayler, Gary S.; Stacey, Gary

    1998-01-01

    The potential for biodegradation of aromatic hydrocarbons was evaluated in soil samples recovered along gradients of both contaminant levels and pH values existing downstream of a long-term coal pile storage basin. pH values for areas greatly impacted by runoff from the storage basin were 2.0. Even at such a reduced pH, the indigenous microbial community was metabolically active, showing the ability to oxidize more than 40% of the parent hydrocarbons, naphthalene and toluene, to carbon dioxide and water. Treatment of the soil samples with cycloheximide inhibited mineralization of the aromatic substrates. DNA hybridization analysis indicated that whole-community nucleic acids recovered from these samples did not hybridize with genes, such as nahA, nahG, nahH, todC1C2, and tomA, that encode common enzymes from neutrophilic bacteria. Since these data suggested that the degradation of aromatic compounds may involve a microbial consortium instead of individual acidophilic bacteria, experiments using microorganisms isolated from these samples were initiated. While no defined mixed cultures were able to evolve 14CO2 from labeled substrates in these mineralization experiments, an undefined mixed culture including a fungus, a yeast, and several bacteria successfully metabolized approximately 27% of supplied naphthalene after 1 week. This study shows that biodegradation of aromatic hydrocarbons can occur in environments with extremely low pH values. PMID:9797263

  12. Diversity of flavin-binding monooxygenase genes (almA) in marine bacteria capable of degradation long-chain alkanes.

    Science.gov (United States)

    Wang, Wanpeng; Shao, Zongze

    2012-06-01

    Many bacteria have been reported as degraders of long-chain (LC) n-alkanes, but the mechanism is poorly understood. Flavin-binding monooxygenase (AlmA) was recently found to be involved in LC-alkane degradation in bacteria of the Acinetobacter and Alcanivorax genera. However, the diversity of this gene and the role it plays in other bacteria remains unclear. In this study, we surveyed the diversity of almA in marine bacteria and in bacteria found in oil-enrichment communities. To identify the presence of this gene, a pair of degenerate PCR primers were was designed based on conserved motifs of the almA gene sequences in public databases. Using this approach, we identified diverse almA genes in the hydrocarbon-degrading bacteria and in bacterial communities from the surface seawater of the Xiamen coastal area, the South China Sea, the Indian Ocean, and the Atlantic Ocean. As a result, almA was positively detected in 35 isolates belonging to four genera, and a total of 39 different almA sequences were obtained. Five isolates were confirmed to harbor two to three almA genes. From the Xiamen coastal area and the Atlantic Ocean oil-enrichment communities, a total of 60 different almA sequences were obtained. These sequences mainly formed two clusters in the phylogenetic tree, named Class I and Class II, and these shared 45-56% identity at the amino acid level. Class I contained 11 sequences from bacteria represented by the Salinisphaera and Parvibaculum genera. Class II was larger and more diverse, and it was composed of 88 sequences from Proteobacteria, Gram-negative bacteria, and the enriched bacterial communities. These communities were represented by the Alcanivorax and Marinobacter genera, which are the two most popular genera hosting the almA gene. AlmA was also detected across a wide geographical range, as determined by the origin of the bacterial host. Our results demonstrate the diversity of almA and confirm its high rate of occurrence in hydrocarbon-degrading

  13. Initial microbial degradation of polycyclic aromatic hydrocarbons

    Directory of Open Access Journals (Sweden)

    Milić Jelena

    2016-01-01

    Full Text Available The group of polycyclic aromatic hydrocarbons (PAHs are very hazardous environmental pollutants because of their mutagenic, carcinogenic and toxic effects on living systems. The aim of this study was to examine and compare the ability and efficiency of selected bacterial isolates obtained from oil-contaminated areas to biodegrade PAHs. The potential of the bacteria to biodegrade various aromatic hydrocarbons was assessed using the 2,6-dichlorophenol-indophenol assay. Further biodegradation of PAHs was monitored by gravimetric and gas-chromatographic analysis. Among the eight bacterial isolates, identified on the basis of 16S rDNA sequences, two isolates, Planomicrobium sp. RNP01 and Rhodococcus sp. RNP05, had the ability to grow on and utilize almost all examined hydrocarbons. Those isolates were further examined for biodegradation of phenanthrene and pyrene, as single substrates, and as a mixture, in vitro for ten days. After three days, both isolates degraded a significant amount phenanthrene, which has a simpler chemical structure than pyrene. Planomicrobium sp.RNP01 commenced biodegradation of pyrene in the PAH mixture only after it had almost completly degraded phenanthrene. The isolated and characterized bacteria, Planomicrobium sp. RNP01 and Rhodococcus sp. RNP05, have shown high bioremediation potential and are likely candidates to be used for degradation of highly toxic PAHs in contaminated areas. [Projekat Ministarstva nauke Republike Srbije, br. III43004

  14. Optimization of low ring polycylic aromatic biodegradation

    Science.gov (United States)

    Othman, N.; Abdul-Talib, S.; Tay, C. C.

    2016-07-01

    Polycyclic aromatic hydrocarbons (PAHs) are recalcitrance and persistence that finally turn into problematic environmental contaminants. Microbial degradation is considered to be the primary mechanism of PAHs removal from the environment due to its organic criteria. This study is carried out to optimize degradation process of low ring PAHs. Bacteria used in this study was isolated from sludge collected from Kolej Mawar, Universiti Teknologi MARA, Shah Alam, Selangor. Working condition namely, substrate concentration, bacteria concentration, pH and temperature were optimized. PAHs in the liquid sample was extracted by using solid phase microextractio equipped with a 7 µm polydimethylsiloxane (PDMS) SPME fibr. Removal of PAHs were assessed by measuring PAHs concentration using GC-FID. Results from the optimization study of biodegradation indicated that maximum rate of PAHs removal occurred at 100 mgL-1 of PAHs, 10% bacteria concentration, pH 7.0 and 30°C. These working condition had proved the effectiveness of using bacteria in biodegradation process of PAHs.

  15. Anaerobic degradation of benzoate by sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Silva, S.P.; Adorno, M.A.T.; Moraes, E.M.; Varesche, M.B.A. [Sao Paulo Univ., Sao Carlos, SP (Brazil). Biological Processes Laboratory

    2004-07-01

    Anaerobic processes are an efficient way to degrade aromatic compounds in industrial wastewater, such as phenol, cresol and benzoate. This study characterized the bacteria that degrades benzoate, an anaerobic degradation intermediate of several complex aromatic compounds. In particular, the study assessed the capacity to use benzoate with sulfate reducing bacteria in mesophilic conditions. Biofilm from polyurethane foam matrices of a fixed bed reactor was used as the cellular inoculum to treat industrial wastewater containing organic peroxide. Dilution techniques were used to purify the material and obtain cultures of cocci. The benzoate consumption capacity in sulfidogenic conditions was observed when the purified inoculum was applied to batch reactors with different benzoate/sulfate relations. Results indicate that purification was positive to bacteria that can degrade aromatic compounds. Desulfococcus multivorans bacteria was identified following the physiologic and kinetic experiments. The 0.6 benzoate/sulfate relation was considered ideal for complete consumption of carbon and total use of sulfur. 10 refs., 3 figs.

  16. Aromaticity Competition in Differentially Fused Borepin-Containing Polycyclic Aromatics.

    Science.gov (United States)

    Messersmith, Reid E; Siegler, Maxime A; Tovar, John D

    2016-07-01

    This report describes the synthesis and characterization of a series of borepin-based polycyclic aromatics bearing two different arene fusions. The borepin synthesis features streamlined Ti-mediated alkyne reduction, leading to Z-olefins, followed by direct lithiation and borepin formation. These molecules allow for an assessment of aromatic competition between the fused rings and the central borepin core. Crystallographic, magnetic, and computational studies yielded insights about the aromaticity of novel, differentially fused [b,f]borepins and allowed for comparison to literature compounds. Multiple borepin motifs were also incorporated into polycyclic aromatics with five or six rings in the main backbone, and their properties were also evaluated.

  17. Biodegradation of Mixed PAHs by PAH-Degrading Endophytic Bacteria

    OpenAIRE

    Xuezhu Zhu; Xue Ni; Michael Gatheru Waigi; Juan Liu; Kai Sun; Yanzheng Gao

    2016-01-01

    Endophytic bacteria can promote plant growth, induce plant defence mechanisms, and increase plant resistance to organic contaminants. The aims of the present study were to isolate highly PAH-degrading endophytic bacteria from plants growing at PAH-contaminated sites and to evaluate the capabilities of these bacteria to degrade polycyclic aromatic hydrocarbons (PAHs) in vitro, which will be beneficial for re-colonizing target plants and reducing plant PAH residues through the inoculation of pl...

  18. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB

    2001-01-01

    A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria......, Thiomargarita namibiensis, with a diameter of 750 mum. All bacteria, including those that swim around in the environment, obtain their food molecules by molecular diffusion. Only the fastest and largest swimmers known, Thiovulum majus, are able to significantly increase their food supply by motility...... and by actively creating an advective flow through the entire population. Diffusion limitation generally restricts the maximal size of prokaryotic cells and provides a selective advantage for mum-sized cells at the normally low substrate concentrations in the environment. The largest heterotrophic bacteria...

  19. Anaerobic bacteria

    Science.gov (United States)

    Brook I, Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 297. Stedman's Online ...

  20. Contorted polycyclic aromatics.

    Science.gov (United States)

    Ball, Melissa; Zhong, Yu; Wu, Ying; Schenck, Christine; Ng, Fay; Steigerwald, Michael; Xiao, Shengxiong; Nuckolls, Colin

    2015-02-17

    CONSPECTUS: This Account describes a body of research in the design, synthesis, and assembly of molecular materials made from strained polycyclic aromatic molecules. The strain in the molecular subunits severely distorts the aromatic molecules away from planarity. We coined the term "contorted aromatics" to describe this class of molecules. Using these molecules, we demonstrate that the curved pi-surfaces are useful as subunits to make self-assembled electronic materials. We have created and continue to study two broad classes of these "contorted aromatics": discs and ribbons. The figure that accompanies this conspectus displays the three-dimensional surfaces of a selection of these "contorted aromatics". The disc-shaped contorted molecules have well-defined conformations that create concave pi-surfaces. When these disc-shaped molecules are substituted with hydrocarbon side chains, they self-assemble into columnar superstructures. Depending on the hydrocarbon substitution, they form either liquid crystalline films or macroscopic cables. In both cases, the columnar structures are photoconductive and form p-type, hole- transporting materials in field effect transistor devices. This columnar motif is robust, allowing us to form monolayers of these columns attached to the surface of dielectrics such as silicon oxide. We use ultrathin point contacts made from individual single-walled carbon nanotubes that are separated by a few nanometers to probe the electronic properties of short stacks of a few contorted discs. We find that these materials have high mobility and can sense electron-deficient aromatic molecules. The concave surfaces of these disc-shaped contorted molecules form ideal receptors for the molecular recognition and assembly with spherical molecules such as fullerenes. These interfaces resemble ball-and-socket joints, where the fullerene nests itself in the concave surface of the contorted disc. The tightness of the binding between the two partners can be

  1. Diverse sulfate-reducing bacteria of the Desulfosarcina/Desulfococcus clade are the key alkane degraders at marine seeps.

    Science.gov (United States)

    Kleindienst, Sara; Herbst, Florian-Alexander; Stagars, Marion; von Netzer, Frederick; von Bergen, Martin; Seifert, Jana; Peplies, Jörg; Amann, Rudolf; Musat, Florin; Lueders, Tillmann; Knittel, Katrin

    2014-10-01

    Biogeochemical and microbiological data indicate that the anaerobic oxidation of non-methane hydrocarbons by sulfate-reducing bacteria (SRB) has an important role in carbon and sulfur cycling at marine seeps. Yet, little is known about the bacterial hydrocarbon degraders active in situ. Here, we provide the link between previous biogeochemical measurements and the cultivation of degraders by direct identification of SRB responsible for butane and dodecane degradation in complex on-site microbiota. Two contrasting seep sediments from Mediterranean Amon mud volcano and Guaymas Basin (Gulf of California) were incubated with (13)C-labeled butane or dodecane under sulfate-reducing conditions and analyzed via complementary stable isotope probing (SIP) techniques. Using DNA- and rRNA-SIP, we identified four specialized clades of alkane oxidizers within Desulfobacteraceae to be distinctively active in oxidation of short- and long-chain alkanes. All clades belong to the Desulfosarcina/Desulfococcus (DSS) clade, substantiating the crucial role of these bacteria in anaerobic hydrocarbon degradation at marine seeps. The identification of key enzymes of anaerobic alkane degradation, subsequent β-oxidation and the reverse Wood-Ljungdahl pathway for complete substrate oxidation by protein-SIP further corroborated the importance of the DSS clade and indicated that biochemical pathways, analog to those discovered in the laboratory, are of great relevance for natural settings. The high diversity within identified subclades together with their capability to initiate alkane degradation and growth within days to weeks after substrate amendment suggest an overlooked potential of marine benthic microbiota to react to natural changes in seepage, as well as to massive hydrocarbon input, for example, as encountered during anthropogenic oil spills.

  2. Petrochemistry - Aromatics; Petrochimie - Aromatiques

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2005-09-01

    The assignment of Unipetrol chemical activities to the Czech group Agrofert by the Polish PKN Orlen is suspended and would be renegotiated. Oman Oil Company (OOC) is joining in the Korean LG International and in its subsidiary company Oman Refinery Company (ORC) for the construction of its new aromatics complex on its site of Sohar (Oman). This plan represents an investment of one milliard of dollars; it will produce 800000 t/year of para-xylene and 210000 t/year of benzene. The unit would be operational at the third trimester 2008. (O.M.)

  3. Fluorinated aromatic diamine

    Science.gov (United States)

    Jones, Robert J. (Inventor); O'Rell, Michael K. (Inventor); Hom, Jim M. (Inventor)

    1980-01-01

    This invention relates to a novel aromatic diamine and more particularly to the use of said diamine for the preparation of thermally stable high-molecular weight polymers including, for example, polyamides, polyamideimides, polyimides, and the like. This diamine is obtained by reacting a stoichometric amount of a disodium salt of 2,2-bis(4-hydroxyphenyl) hexafluoropropane with 4-chloronitrobenzene to obtain an intermediate, 2,2-bis[4-(4-nitrophenoxy)phenyl] hexafluoropropane, which is reduced to the corresponding 2,2-bis[4-(4-aminophenoxy)phenyl] hexafluoropropane.

  4. Degradation of benzene and other aromatic hydrocarbons by anaerobic bacteria

    NARCIS (Netherlands)

    Weelink, S.A.B.

    2008-01-01

    Accidental spills, industrial discharges and gasoline leakage from underground storage tanks have resulted in serious pollution of the environment with monoaromatic hydrocarbons, such as benzene, toluene, ethylbenzene and xylene (so-called BTEX). High concentrations of BTEX have been detected in soi

  5. "Carbo-aromaticity" and novel carbo-aromatic compounds.

    Science.gov (United States)

    Cocq, Kévin; Lepetit, Christine; Maraval, Valérie; Chauvin, Remi

    2015-09-21

    While the concept of aromaticity is being more and more precisely delineated, the category of "aromatic compounds" is being more and more expanded. This is illustrated by an introductory highlight of the various types of "aromaticity" previously invoked, and by a focus on the recently proposed "aromatic character" of the "two-membered rings" of the acetylene and butatriene molecules. This serves as a general foundation for the definition of "carbo-aromaticity", the relevance of which is surveyed through recent results in the synthetic, physical, and theoretical chemistry of carbo-mers and in particular macrocyclic-polycyclic representatives constituting a natural family of "novel aromatic compounds". With respect to their parent molecules, carbo-mers are constitutionally defined as "carbon-enriched", and can also be functionally regarded as "π-electron-enriched". This is exemplified by recent experimental and theoretical results on functional, aromatic, rigid, σ,π-macrocyclic carbo-benzene archetypes of various substitution patterns, with emphasis on the quadrupolar pattern. For the purpose of comparison, several types of non-aromatic references of carbo-benzenes are then considered, i.e. freely rotating σ,π-acyclic carbo-n-butadienes and flexible σ-cyclic, π-acyclic carbo-cyclohexadienes, and to "pro-aromatic" congeners, i.e. rigid σ,π-macrocyclic carbo-quinoids. It is shown that functional carbo-mers are entering the field of "molecular materials" for properties such as linear or nonlinear optical properties (e.g. dichromism and two-photon absorption) and single molecule conductivity. Since total or partial carbo-mers of aromatic carbon-allotropes of infinite size such as graphene (graphynes and graphdiynes) and graphite ("graphitynes") have long been addressed at the theoretical or conceptual level, recent predictive advances on the electrical, optical and mechanical properties of such carbo-materials are surveyed. Very preliminary experimental results

  6. Bacterial Degradation of Aromatic Compounds

    Directory of Open Access Journals (Sweden)

    Qing X. Li

    2009-01-01

    Full Text Available Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms.

  7. Effects of bio stimulation on growth of indigenous bacteria in sub-antarctic soil contaminated with oil hydrocarbons; Effets de traitements de biostimulation sur la croissance des bacteries indigenes d'un sol subantarctique contamine par des hydrocarbures

    Energy Technology Data Exchange (ETDEWEB)

    Coulon, F.; Delille, D. [Universite Pierre et Marie Curie, Observatoire Oceanologique, UMR-CNRS 7621, 66 - Banyuls sur Mer (France)

    2003-08-01

    In order to evaluate the efficiency of bio-stimulation of soil contaminated with oil hydrocarbons under sub-Antarctic conditions, a meso-cosm study was initiated in May 2001 in the Kerguelen Archipelago (49 deg. 21'S, 70 deg. 13'E). The effects of temperature and fertilizer addition (Inipol EAP-22, Elf Atochem) on soil bacterial assemblages contaminated with hydrocarbons were studied in 6-l batches of sub-antarctic soil incubated in the dark. Six different conditions were used at three temperatures (4, 10 and 20 deg. C): control, fertilizer (50 ml), diesel oil (100 ml), diesel oil (100 ml) + fertilizer (50 ml), 'Arabian light' crude oil (100 ml) and crude oil (100 ml) + fertilizer (50 ml). Meso-cosms were sampled on a regular basis over a seven-month period. All samples were analyzed for total bacteria, viable heterotrophic assemblages and hydrocarbon-utilising microflora. The results clearly showed a significant response of sub-Antarctic microbial soil communities to hydrocarbon contamination. Large increases in total, heterotrophic and hydrocarbon-utilising bacteria were observed (from less than 5 x 10{sup 5} MPN g{sup -1} to more than 10{sup 8} MPN g{sup -1} for hydrocarbon degrading bacteria). Temperature elevation had no significant impact on the total or heterotrophic assemblages but induced a one order of magnitude increase in hydrocarbon-utilising bacteria in contaminated meso-cosms. In contrast, fertilizer addition had no clear effect on hydrocarbon-degrading specific bacteria but stimulated heterotrophic growth in diesel oil-contaminated soils. (authors)

  8. Potential of grasses and rhizosphere bacteria for bioremediation of diesel-contaminated soils

    Directory of Open Access Journals (Sweden)

    Melissa Paola Mezzari

    2011-12-01

    Full Text Available The techniques available for the remediation of environmental accidents involving petroleum hydrocarbons are generally high-cost solutions. A cheaper, practical and ecologically relevant alternative is the association of plants with microorganisms that contribute to the degradation and removal of hydrocarbons from the soil. The growth of three tropical grass species (Brachiaria brizantha, Brachiaria decumbens and Paspalum notatum and the survival of root-associated bacterial communities was evaluated at different diesel oil concentrations. Seeds of three grass species were germinated in greenhouse and at different doses of diesel (0, 2.5, 5 and 10 g kg-1 soil. Plants were grown for 10 weeks with periodic assessment of germination, growth (fresh and dry weight, height, and number of bacteria in the soil (pots with or without plants. Growth and biomass of B. decumbens and P. notatum declined significantly when planted in diesel-oil contaminated soils. The presence of diesel fuel did not affect the growth of B. brizantha, which was highly tolerant to this pollutant. Bacterial growth was significant (p < 0.05 and the increase was directly proportional to the diesel dose. Bacteria growth in diesel-contaminated soils was stimulated up to 5-fold by the presence of grasses, demonstrating the positive interactions between rhizosphere and hydrocarbon-degrading bacteria in the remediation of diesel-contaminated soils.

  9. Advances towards aromatic oligoamide foldamers

    DEFF Research Database (Denmark)

    Hjelmgaard, Thomas; Plesner, Malene; Dissing, Mette Marie;

    2014-01-01

    We have efficiently synthesized 36 arylopeptoid dimers with ortho-, meta-, and para-substituted aromatic backbones and tert-butyl or phenyl side chains. The dimers were synthesized by using a "submonomer method" on solid phase, by applying a simplified common set of reaction conditions. X......-ray crystallographic analysis of two of these dimers disclosed that the tert-butyl side chain invokes a cis amide conformation with a comparatively more closely packed structure of the surrounding aromatic backbone while the phenyl side chain results in a trans amide conformation with a more open, extended structure...... of the surrounding aromatic backbone. Investigation of the X-ray structures of two arylopeptoid dimers disclosed that the tert-butyl side chain invokes a cis amide conformation with a closely packed structure of the surrounding aromatic backbone while the phenyl side chain results in a trans amide conformation...

  10. Bioassay of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Van Kirk, E.A.

    1980-08-01

    A positive relationship was found between the photodynamic activity of 24 polycyclic aromatic hydrocarbons versus published results on the mutagenicity, carcinogenicity, and initiation of unscheduled DNA synthesis. Metabolic activation of benzo(a)pyrene resulted in detection of increased mutagenesis in Paramecium tetraurelia as found also in the Ames Salmonella assay. The utility of P. tetraurelia as a biological detector of hazardous polycyclic aromatic hydrocarbons is discussed.

  11. Polycyclic Aromatic Hydrocarbons

    Science.gov (United States)

    Salama, Farid

    2010-01-01

    Carbonaceous materials play an important role in space. Polycyclic Aromatic Hydrocarbons (PAHs) are a ubiquitous component of the carbonaceous materials. PAHs are the best-known candidates to account for the IR emission bands. They are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge is to reproduce in the laboratory the physical conditions that exist in the emission and absorption interstellar zones. The harsh physical conditions of the ISM -low temperature, collisionless, strong UV radiation fields- are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions and radicals are formed from the neutral precursors in an isolated environment at low temperature and probed with high-sensitivity cavity ringdown spectroscopy in the NUV-NIR range. Carbon nanoparticles are also formed during the short residence time of the precursors in the plasma and are characterized with time-offlight mass spectrometry. These experiments provide unique information on the spectra of large carbonaceous molecules and ions in the gas phase that can now be directly compared to interstellar and circumstellar observations (IR emission bands, DIBs, extinction curve). These findings also hold great potential for understanding the formation process of interstellar carbonaceous grains. We will review recent progress in the experimental and theoretical studies of PAHs, compare the laboratory data with astronomical observations and discuss the global implications.

  12. Novel diesel-oil-degrading bacteria and fungi from the Ecuadorian Amazon rainforest.

    Science.gov (United States)

    Maddela, N R; Masabanda, M; Leiva-Mora, M

    2015-01-01

    Isolating new diesel-oil-degrading microorganisms from crude-oil contaminated sites and evaluating their degradation capacities are vitally important in the remediation of oil-polluted environments and crude-oil exploitation. In this research, new hydrocarbon-degrading bacteria and fungi were isolated from the crude-oil contaminated soil of the oil-fields in the Amazon rainforest of north-east Ecuador by using a soil enrichment technique. Degradation analysis was tracked by gas chromatography and a flame ionization detector. Under laboratory conditions, maximum degradability of the total n-alkanes reached up to 77.34 and 62.62 removal ratios after 30 days of incubation for the evaporated diesel oil by fungi (isolate-1) and bacteria (isolate-1), respectively. The 16S/18S rDNA sequence analysis indicated that the microorganisms were most closely (99-100%) related to Bacillus cereus (isolate-1), Bacillus thuringiensis (isolate-2), Geomyces pannorum (isolate-1), and Geomyces sp. (isolate-2). Therefore, these strains enable the degradation of hydrocarbons as the sole carbon source, and these findings will benefit these strains in the remediation of oil-polluted environments and oil exploitation.

  13. Phylogenetic and functional diversity of alkane degrading bacteria associated with Italian ryegrass (Lolium multiflorum) and Birdsfoot trefoil (Lotus corniculatus) in a petroleum oil-contaminated environment.

    Science.gov (United States)

    Yousaf, Sohail; Andria, Verania; Reichenauer, Thomas G; Smalla, Kornelia; Sessitsch, Angela

    2010-12-15

    Twenty-six different plant species were analyzed regarding their performance in soil contaminated with petroleum oil. Two well-performing species, Italian ryegrass (Lolium multiflorum var. Taurus), Birdsfoot trefoil (Lotus corniculatus var. Leo) and the combination of these two plants were selected to study the ecology of plant-associated, culturable alkane-degrading bacteria. Hydrocarbon degrading bacteria were isolated from the rhizosphere, root interior and shoot interior and subjected to the analysis of 16S rRNA gene, the 16S and 23S rRNA intergenic spacer region and alkane hydroxylase genes. Furthermore, we investigated whether alkane hydroxylase genes are plasmid located. Higher numbers of culturable, alkane-degrading bacteria were associated with Italian ryegrass, which were also characterized by a higher diversity, particularly in the plant interior. Only half of the isolated bacteria hosted known alkane hydroxylase genes (alkB and cytochrome P153-like). Degradation genes were found both on plasmids as well as in the chromosome. In regard to application of plants for rhizodegradation, where support of numerous degrading bacteria is essential for efficient break-down of pollutants, Italian ryegrass seems to be more appropriate than Birdsfoot trefoil.

  14. Aromatic-Aromatic Interactions in Biological System: Structure Activity Relationships

    Energy Technology Data Exchange (ETDEWEB)

    Rajagopal, Appavu; Deepa, Mohan [Molecular Biophysics Unit, Indian Institute of Sciences-Bangalore, Karnataka (India); Govindaraju, Munisamy [Bio-Spatial Technology Research Unit, Department of Environmental Biotechnology, School of Environmental Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu (India)

    2016-02-26

    While, intramolecular hydrogen bonds have attracted the greatest attention in studies of peptide conformations, the recognition that several other weakly polar interactions may be important determinants of folded structure has been growing. Burley and Petsko provided a comprehensive overview of the importance of weakly polar interactions, in shaping protein structures. The interactions between aromatic rings, which are spatially approximate, have attracted special attention. A survey of the proximal aromatic residue pairs in proteins, allowed Burley and Petsko to suggest that, “phenyl ring centroids are separated by a preferential distance of between 4.5 and 7 Å, and dihedral angles approximately 90° are most common”.

  15. Degradation and assimilation of aromatic compounds by Corynebacterium glutamicum: another potential for applications for this bacterium?

    Science.gov (United States)

    Shen, Xi-Hui; Zhou, Ning-Yi; Liu, Shuang-Jiang

    2012-07-01

    With the implementation of the well-established molecular tools and systems biology techniques, new knowledge on aromatic degradation and assimilation by Corynebacterium glutamicum has been emerging. This review summarizes recent findings on degradation of aromatic compounds by C. glutamicum. Among these findings, the mycothiol-dependent gentisate pathway was firstly discovered in C. glutamicum. Other important knowledge derived from C. glutamicum would be the discovery of linkages among aromatic degradation and primary metabolisms such as gluconeogenesis and central carbon metabolism. Various transporters in C. glutamicum have also been identified, and they play an essential role in microbial assimilation of aromatic compounds. Regulation on aromatic degradation occurs mainly at transcription level via pathway-specific regulators, but global regulator(s) is presumably involved in the regulation. It is concluded that C. glutamicum is a very useful model organism to disclose new knowledge of biochemistry, physiology, and genetics of the catabolism of aromatic compounds in high GC content Gram-positive bacteria, and that the new physiological properties of aromatic degradation and assimilation are potentially important for industrial applications of C. glutamicum.

  16. Optimisation of Environmental Factors on Oil Degrading Bacteria Isolated from Coastal Water and Sediments in Sri Lanka

    Directory of Open Access Journals (Sweden)

    GY Liyanage

    2015-12-01

    Full Text Available Better understanding of the mechanisms of hydrocarbon degrading microorganisms and effect of some environmental factors is critical for the optimisation of the bioremediation processes. Temperature, pH, nitrate and phosphate are the major factors that influence there mediation process of bacterium. In the present study, optimisations some selected physico-chemical parameters (temperature, pH, nitrate and phosphate were carried out on Bacillus cereus, Enterobacter sp. and Enterobacter ludwigii which were previously isolated as potential oil degraders. The bacteria showed maximum degradation of crude oil at 33o C where the desirable pH was 8.6 for all the isolates except E. ludwigii (pH 5.4. A significant degradation (p < 0.05 of oil was detected by B. cereus (80% to 98%, Enterobacter sp. (73% to 90% and E. ludwigii (70% to 83% respectively with increasing of nitrate concentration from 0.1 to 2.5 ppm. Significant degradation of oil was not detected in the control and when bacteria were enriched with phosphate. Results of this study revealed that the bacterial remediation of oil is governed by nutritional status with special emphasis of nitrate enrichment in the environment. Thus, the results revealed that bacteria could be a useful tool to remove oil from the contaminated environment as eco-friendly, low cost application.

  17. Protocal for the measurement of hydrocarbon transport in bacteria

    Science.gov (United States)

    Due to the hydrophobic, volatility, and relatively low aqueous solubility of aliphatic and aromatic hydrocarbons, transport of these chemicals by bacteria has not been extensively studied. These issues make transport assays difficult to carry out, and as a result, strong evidence for the active tran...

  18. Rhizosphere Bacteria

    Directory of Open Access Journals (Sweden)

    N.V. Feoktistova

    2016-06-01

    Full Text Available The review deals with the analysis of modern literature data on rhizosphere bacteria and their role in plant life. The structure of rhizosphere has been characterized. The role of plants as the centers of formation of microbial communities has been shown. Data on the main groups of microorganisms inhabiting the rhizosphere have been provided. The associative relationship between rhizobacteria and partner plants has been investigated. The modern concept of holobiont defined as the whole host plant organism and microorganisms associated with it has been reviewed. The role of rhizobacteria in the processes of nitrogen fixation has been discussed in detail. The mechanisms of direct stimulation of plant growth by biosynthesis of phytohormones, improvement of phosphorus and nitrogen nutrition, increase in resistance to stress, and stimulation mediated by antagonism against pathogenic microorganisms have been analyzed. The criteria for selection of rhizobacteria for practical purposes have been discussed.

  19. Aromaticity of group 14 organometallics: experimental aspects.

    Science.gov (United States)

    Lee, Vladimir Ya; Sekiguchi, Akira

    2007-01-01

    The long story of aromatic compounds has extended over almost two centuries, since the discovery by Faraday of "bicarburet of hydrogen", or C(6)H(6), now called benzene. Since then, the chemistry of aromatic compounds has been developed extensively; this is reflected in the synthesis of novel classes of aromatic derivatives including charged species, nonclassical (Möbius, three-dimensional, homo-, metalla-) aromatics, and fullerenes. The theory of aromaticity has also undergone a spectacular evolution since the first definition of aromaticity by Hückel; the classification of aromaticity now requires the consideration of versatile criteria: energetic, structural, magnetic, among others. In this Review, we discuss the current state of affairs in the chemistry of aromatic compounds of the heavier Group 14 elements, the latest experimental achievements, as well as future prospects in the field.

  20. Biodegradation Mechanism and Technology of Polycyclic Aromatic Hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    DIAO Shuo; WANG Hong-qi; ZHENG Yi-nan; HUA Fei

    2016-01-01

    [Abstract]Polycyclic aromatic hydrocarbons are a class of potentially hazardous chemicals of environmental and health concern.PAHs are one of the most prevalent groups of contaminants found in soil.Biodegradation of complex hydrocarbon usually requires the cooperation of more than single specie.This paper reviews the existing screening methods of PAH-degrading bacteria.It studied the mechanism and technical applications of the co-metabolism in PAHs.Author gives the suggestions and prospects in Biodegradable trend of PHAs.

  1. Bacterial conversion of phenylalanine and aromatic carboxylic acids into dihydrodiols.

    Science.gov (United States)

    Wegst, W; Tittmann, U; Eberspächer, J; Lingens, F

    1981-03-15

    Strain E of chloridazon-degrading bacteria, when grown on L-phenylalanine accumulates cis-2,3-dihydro-2,3-dihydroxyphenylalanine. In experiments with resting cells and during growth the bacterium converts the aromatic carboxylic acids phenylacetate, phenylpropionate, phenylbutyrate and phenyl-lactate into the corresponding cis-2,3-dihydrodiol compounds. The amino acids L-phenylalanine, N-acetyl-L-phenylalanine and t-butyloxycarbonyl-L-phenylalanine were also transformed into dihydrodiols. All seven dihydrodiols, thus obtained, were characterized both by conventional analytical techniques and by the ability to serve as substrates for a cis-dihydrodiol dehydrogenase.

  2. Anaerobic degradation of homocyclic aromatic compounds via arylcarboxyl-coenzyme A esters: organisms, strategies and key enzymes.

    Science.gov (United States)

    Boll, Matthias; Löffler, Claudia; Morris, Brandon E L; Kung, Johannes W

    2014-03-01

    Next to carbohydrates, aromatic compounds are the second most abundant class of natural organic molecules in living organic matter but also make up a significant proportion of fossil carbon sources. Only microorganisms are capable of fully mineralizing aromatic compounds. While aerobic microbes use well-studied oxygenases for the activation and cleavage of aromatic rings, anaerobic bacteria follow completely different strategies to initiate catabolism. The key enzymes related to aromatic compound degradation in anaerobic bacteria are comprised of metal- and/or flavin-containing cofactors, of which many use unprecedented radical mechanisms for C-H bond cleavage or dearomatization. Over the past decade, the increasing number of completed genomes has helped to reveal a large variety of anaerobic degradation pathways in Proteobacteria, Gram-positive microbes and in one archaeon. This review aims to update our understanding of the occurrence of aromatic degradation capabilities in anaerobic microorganisms and serves to highlight characteristic enzymatic reactions involved in (i) the anoxic oxidation of alkyl side chains attached to aromatic rings, (ii) the carboxylation of aromatic rings and (iii) the reductive dearomatization of central arylcarboxyl-coenzyme A intermediates. Depending on the redox potential of the electron acceptors used and the metabolic efficiency of the cell, different strategies may be employed for identical overall reactions.

  3. Isolation and Characterization of Surface and Subsurface Bacteria in Seawater of Mantanani Island, Kota Belud, Sabah by Direct and Enrichment Techniques

    Science.gov (United States)

    Benard, L. D.; Tuah, P. M.; Suadin, E. G.; Jamian, N.

    2015-04-01

    The distribution of hydrocarbon-utilizing bacterial may vary between surface and subsurface of the seawater. One of the identified contributors is the Total Petroleum Hydrocarbon. The isolation and characterization of bacteria using Direct and Enrichment techniques helps in identifying dominant bacterial populations in seawater of Mantanani Island, Kota Belud, Sabah, potential of further investigation as hydrocarbon degrader. Crude oil (5% v/v) was added as the carbon source for bacteria in Enrichment technique. For surface seawater, the highest population of bacteria identified for both Direct and Enrichment technique were 2.60 × 107 CFU/mL and 3.84 × 106 CFU/mL respectively. Meanwhile, for subsurface seawater, the highest population of bacteria identified for both Direct and Enrichment technique were 5.21 × 106 CFU/mL and 8.99 × 107 CFU/mL respectively. Dominant species in surface seawater were characterized as Marinobacter hydrocarbonoclasticus-RMSF-C1 and RMSF-C2 and Alcanivorax borkumensis-RMSF-C3, RMSF-C4 and RMSF-C5. As for subsurface seawater, dominant species were characterized as Pseudomonas luteola-SSBR-W1, Burkholderia cepacia-SSBR-C1, Rhizobium radiobacter- SSBR-C3 and Leuconostoc-cremois -SSBR-C4.

  4. Azoarcus sp. CIB, an anaerobic biodegrader of aromatic compounds shows an endophytic lifestyle.

    Directory of Open Access Journals (Sweden)

    Helga Fernández

    Full Text Available BACKGROUND: Endophytic bacteria that have plant growth promoting traits are of great interest in green biotechnology. The previous thought that the Azoarcus genus comprises bacteria that fit into one of two major eco-physiological groups, either free-living anaerobic biodegraders of aromatic compounds or obligate endophytes unable to degrade aromatics under anaerobic conditions, is revisited here. METHODOLOGY/PRINCIPAL FINDINGS: Light, confocal and electron microscopy reveal that Azoarcus sp. CIB, a facultative anaerobe β-proteobacterium able to degrade aromatic hydrocarbons under anoxic conditions, is also able to colonize the intercellular spaces of the rice roots. In addition, the strain CIB displays plant growth promoting traits such nitrogen fixation, uptake of insoluble phosphorus and production of indoleacetic acid. Therefore, this work demonstrates by the first time that a free-living bacterium able to degrade aromatic compounds under aerobic and anoxic conditions can share also an endophytic lifestyle. The phylogenetic analyses based on the 16S rDNA and nifH genes confirmed that obligate endophytes of the Azoarcus genus and facultative endophytes, such as Azoarcus sp. CIB, locate into different evolutionary branches. CONCLUSIONS/SIGNIFICANCE: This is the first report of a bacterium, Azoarcus sp. CIB, able to degrade anaerobically a significant number of aromatic compounds, some of them of great environmental concern, and to colonize the rice as a facultative endophyte. Thus, Azoarcus sp. CIB becomes a suitable candidate for a more sustainable agricultural practice and phytoremediation technology.

  5. Potential application of aromatic plant extracts to prevent cheese blowing.

    Science.gov (United States)

    Librán, C M; Moro, A; Zalacain, A; Molina, A; Carmona, M; Berruga, M I

    2013-07-01

    This study aimed to inhibit the growth of Escherichia coli and Clostridium tyrobutyricum, common bacteria responsible for early and late cheese blowing defects respectively, by using novel aqueous extracts obtained by dynamic solid-liquid extraction and essential oils obtained by solvent free microwave extraction from 12 aromatic plants. In terms of antibacterial activity, a total of 13 extracts inhibited one of the two bacteria, and only two essential oils, Lavandula angustifolia Mill. and Lavandula hybrida, inhibited both. Four aqueous extracts were capable of inhibiting C. tyrobutyricum, but none were effective against E. coli. After extracts' chemical composition identification, relationship between the identified compounds and their antibacterial activity were performed by partial least square regression models revealing that compounds such as 1,8 cineole, linalool, linalyl acetate, β-phellandrene or verbene (present in essential oils), pinocarvone, pinocamphone or coumaric acid derivate (in aqueous extracts) were compounds highly correlated to the antibacterial activity.

  6. Study on biodegradable aromatic/aliphatic copolyesters

    Energy Technology Data Exchange (ETDEWEB)

    Yiwang Chen; Licheng Tan; Lie Chen; Yan, Yang; Xiaofeng Wang [Nanchang University, Nanchang (China). School of Materials Science and Engineering. Inst. of Polymer Materials]. E-mail: ywchen@ncu.edu.cn

    2008-04-15

    Progress on biodegradable aromatic/aliphatic copolyesters based on aliphatic and aromatic diacids, diols and ester monomers was reviewed. The aromatic/aliphatic copolyesters combined excellent mechanical properties with biodegradability. Physical properties and biodegradability of copolyesters varied with chain length of the aliphatic polyester segment and atacticity of copolyesters. The process ability of copolyesters could be improved significantly after incorporating a stiff chain segment through copolymerization of aliphatic polyesters with an aromatic liquid crystal element. The aromatic/aliphatic copolyesters as a new type of biodegradable materials could replace some general plastics in certain applications, namely biomedical and environmental friendly fields. (author)

  7. CHARACTERISTICS OF AROMATIC HYDROCARBONS IN CRUDE OILS

    Institute of Scientific and Technical Information of China (English)

    罗斌杰; 李新宇

    1994-01-01

    Crude oils from different basins in China ,Australia and New Zealand were analyzed to character-ize aromatic hydrocarbons produced in different environments by means of GC/MS .The distributions of some common compounds such as naphthalene, phenanthrene, chrysene,pyrene, fluoranthene, fluorine,dibenzothiophene and dibenzofuran were found to be related to sedimentary environments.Especially the relative contents of fluorenes ,dibenzofurans and dibenzothiophenes can be used to di-vide the oils into three types(1) saline or marine carbonate environment;(2) fresh-brackish water lake;(3) swamp and coal-bearing sequence.A romatic biomarkers (e.g.retene, nor-abietene,derivatives of lupeol and β-amyrin)represent higher plant inpults with respect to the precursors of crude oils. High contents of sulphur-containing compounds like benzothiophene and dibenzothiophene series indicate a reducing sulphur-abundant diagenetic condition .The benzohopane series (C32-C35) was identified both in hypersaline and coal-bearing basins, and it is postulated to be the result of strong bacteria activity.In all the sam-ples, a complete series of alkyl benzenes was analyzed .The similarity of its carbon-number distrbu-tion with that of n-alkanes probably suggests their genetic relationship. The distribution of the methylphenanthrene series reflects the evolution degree of crude oils,MPI holding a positive correlation with C29-sterane 20S/(20S+20R).

  8. Ensemble modeling for aromatic production in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Matthew L Rizk

    Full Text Available Ensemble Modeling (EM is a recently developed method for metabolic modeling, particularly for utilizing the effect of enzyme tuning data on the production of a specific compound to refine the model. This approach is used here to investigate the production of aromatic products in Escherichia coli. Instead of using dynamic metabolite data to fit a model, the EM approach uses phenotypic data (effects of enzyme overexpression or knockouts on the steady state production rate to screen possible models. These data are routinely generated during strain design. An ensemble of models is constructed that all reach the same steady state and are based on the same mechanistic framework at the elementary reaction level. The behavior of the models spans the kinetics allowable by thermodynamics. Then by using existing data from the literature for the overexpression of genes coding for transketolase (Tkt, transaldolase (Tal, and phosphoenolpyruvate synthase (Pps to screen the ensemble, we arrive at a set of models that properly describes the known enzyme overexpression phenotypes. This subset of models becomes more predictive as additional data are used to refine the models. The final ensemble of models demonstrates the characteristic of the cell that Tkt is the first rate controlling step, and correctly predicts that only after Tkt is overexpressed does an increase in Pps increase the production rate of aromatics. This work demonstrates that EM is able to capture the result of enzyme overexpression on aromatic producing bacteria by successfully utilizing routinely generated enzyme tuning data to guide model learning.

  9. Comamonas testosteroni uses a chemoreceptor for tricarboxylic acid cycle intermediates to trigger chemotactic responses towards aromatic compounds.

    Science.gov (United States)

    Ni, Bin; Huang, Zhou; Fan, Zheng; Jiang, Cheng-Ying; Liu, Shuang-Jiang

    2013-11-01

    Bacterial chemotaxis towards aromatic compounds has been frequently observed; however, knowledge of how bacteria sense aromatic compounds is limited. Comamonas testosteroni CNB-1 is able to grow on a range of aromatic compounds. This study investigated the chemotactic responses of CNB-1 to 10 aromatic compounds. We constructed a chemoreceptor-free, non-chemotactic mutant, CNB-1Δ20, by disruption of all 19 putative methyl-accepting chemotaxis proteins (MCPs) and the atypical chemoreceptor in strain CNB-1. Individual complementation revealed that a putative MCP (tagged MCP2201) was involved in triggering chemotaxis towards all 10 aromatic compounds. The recombinant sensory domain of MCP2201 did not bind to 3- or 4-hydroxybenzoate, protocatechuate, catechol, benzoate, vanillate and gentisate, but bound oxaloacetate, citrate, cis-aconitate, isocitrate, α-ketoglutarate, succinate, fumarate and malate. The mutant CNB-1ΔpmdF that lost the ability to metabolize 4-hydroxybenzoate and protocatechuate also lost its chemotactic response to these compounds, suggesting that taxis towards aromatic compounds is metabolism-dependent. Based on the ligand profile, we proposed that MCP2201 triggers taxis towards aromatic compounds by sensing TCA cycle intermediates. Our hypothesis was further supported by the finding that introduction of the previously characterized pseudomonad chemoreceptor (McpS) for TCA cycle intermediates into CNB-1Δ20 likewise triggered chemotaxis towards aromatic compounds.

  10. Specialized Hydrocarbonoclastic Bacteria Prevailing in Seawater around a Port in the Strait of Malacca.

    Directory of Open Access Journals (Sweden)

    Maki Teramoto

    Full Text Available Major degraders of petroleum hydrocarbons in tropical seas have been indicated only by laboratory culturing and never through observing the bacterial community structure in actual environments. To demonstrate the major degraders of petroleum hydrocarbons spilt in actual tropical seas, indigenous bacterial community in seawater at Sentosa (close to a port and East Coast Park (far from a port in Singapore was analyzed. Bacterial species was more diverse at Sentosa than at the Park, and the composition was different: γ-Proteobacteria (57.3% dominated at Sentosa, while they did not at the Park. Specialized hydrocarbonoclastic bacteria (SHCB, which use limited carbon sources with a preference for petroleum hydrocarbons, were found as abundant species at Sentosa, indicating petroleum contamination. On the other hand, SHCB were not the abundant species at the Park. The abundant species of SHCB at Sentosa were Oleibacter marinus and Alcanivorax species (strain 2A75 type, which have previously been indicated by laboratory culturing as important petroleum-aliphatic-hydrocarbon degraders in tropical seas. Together with the fact that SHCB have been identified as major degraders of petroleum hydrocarbons in marine environments, these results demonstrate that the O. marinus and Alcanivorax species (strain 2A75 type would be major degraders of petroleum aliphatic hydrocarbons spilt in actual tropical seas.

  11. Nucleophilic fluorination of aromatic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Satyamurthy, Nagichettiar; Barrio, Jorge R

    2014-03-18

    Iodylbenzene derivatives substituted with electron donating as well as electron withdrawing groups on the aromatic ring are used as precursors in aromatic nucleophilic substitution reactions. The iodyl group (IO.sub.2) is regiospecifically substituted by nucleophilic fluoride to provide the corresponding fluoroaryl derivatives. No-carrier-added [F-18]fluoride ion derived from anhydrous [F-18](F/Kryptofix, [F-18]CsF or a quaternary ammonium fluoride (e.g., Me.sub.4NF, Et.sub.4NF, n-Bu.sub.4NF, (PhCH.sub.2).sub.4NF) exclusively substitutes the iodyl moiety in these derivatives and provides high specific activity F-18 labeled fluoroaryl analogs. Iodyl derivatives of a benzothiazole analog and 6-iodyl-L-dopa derivatives have been synthesized as precursors and have been used in the preparation of no-carrier-added [F-18]fluorobenzothiazole as well as 6-[F-18]fluoro-L-dopa.

  12. Alkylation of organic aromatic compounds

    Science.gov (United States)

    Smith, L.A. Jr.

    1989-07-18

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 fig.

  13. APLICACIÓN DE SALES DE TETRAZOLIO DE NUEVA GENERACIÓN (XTT PARA LA ESTIMACIÓN DE LA DENSIDAD DE MICROORGANISMOS DEGRADADORES DE HIDROCARBUROS EMPLEANDO LA TÉCNICA DEL NÚMERO MÁS PROBABLE Application of the New Generation Tetrazolium Salt (XTT for the Enumeration of Hydrocarbon Degrading Microorganisms Using the Most Probable Number Method

    Directory of Open Access Journals (Sweden)

    VICTORIA EUGENIA VALLEJO

    Full Text Available El presente estudio evaluó el desempeño de dos sales de tetrazolio, una tradicional: INT y una de nueva generación: XTT, para estimar la densidad de microorganismos degradadores de hidrocarburos (HCs en suelos empleando la técnica del Número Más Probable (NMP. Se analizaron 96 muestras de suelo provenientes de la Ecorregión Cafetera de Colombia. Los microorganismos fueron recuperados en agar mínimo de sales en atmósfera saturada de HCs y la capacidad degradadora fue confirmada por repiques sucesivos utilizando diesel como fuente de carbono. No se observaron diferencias significativas en los recuentos de microorganismos degradadores obtenidos con las dos sales (t de Student, p The objective of this study was to evaluate the performance of two tetrazolium indicators: a traditional one: INT and a new generation one: XTT, for the estimation of hydrocarbon (HC degrading microorganism s density using the Most Probable Number Technique (MPN. Ninety six composite soil samples were taken and analyzed from Ecorregión Cafetera Colombiana. Degrading microorganisms were recovered in minimum salt medium with saturated HC atmosphere. Degrading HC capacity of the microorganisms was confirmed by successive subcultures in the same medium using diesel as only carbon source. Counts obtained with the two salts were not significantly different (Student t test, p < 0,05 but XTT allowed an easier visualization of positive wells due to product solubility of the reduce product. A greater percentage of isolates was obtained using XTT (67%, which suggests that salt type is relevant for recovering of these microorganisms. Additionally, cell detection limit, optimal conditions of XTT concentration and incubation times for detection of activity were evaluated. This evaluation was performed by means of microplate format for hydrocarbon degrading microorganisms using Acinetobacter sp. An inhibitory effect was observed in the recovering of cultivable cells when XTT

  14. The direct aromatization of methane

    Energy Technology Data Exchange (ETDEWEB)

    Marcelin, G.; Oukaci, R.; Migone, R.A.; Kazi, A.M. [Altamira Instruments, Pittsburgh, PA (United States)

    1995-12-31

    The thermal decomposition of methane shows significant potential as a process for the production of higher unsaturated and aromatic hydrocarbons when the extent of the reaction is limited. Thermodynamic calculations have shown that when the reaction is limited to the formation of C{sub 2} to C{sub 10} products, yields of aromatics can exceed 40% at temperatures of 1200{degrees}C. Preliminary experiments have shown that when the reaction is limited to the formation of C{sub 2} to C{sub 10} products, yields of aromatics can exceed 40% at temperatures of 1200{degrees}C. Preliminary experiments have shown that cooling the product and reacting gases as the reaction proceeds can significantly reduce or eliminate the formation of solid carbon and heavier (C{sub 10+}) materials. Much work remains to be done in optimizing the quenching process and this is one of the goals of this program. Means to lower the temperature of the reaction are being studied as this result in a more feasible commercial process due to savings realized in energy and material of construction costs. The use of free-radical generators and catalysts will be investigated as a means of lowering the reaction temperature thus allowing faster quenching. It is highly likely that such studies will lead to a successful direct methane to higher hydrocarbon process.

  15. Deuterated polycyclic aromatic hydrocarbons: Revisited

    CERN Document Server

    Doney, Kirstin D; Mori, Tamami; Onaka, Takashi; Tielens, A G G M

    2016-01-01

    The amount of deuterium locked up in polycyclic aromatic hydrocarbons (PAHs) has to date been an uncertain value. We present a near-infrared (NIR) spectroscopic survey of HII regions in the Milky Way, Large Magellanic Cloud (LMC), and Small Magellanic Cloud (SMC) obtained with AKARI, which aims to search for features indicative of deuterated PAHs (PAD or Dn-PAH) to better constrain the D/H ratio of PAHs. Fifty-three HII regions were observed in the NIR (2.5-5 {\\mu}m), using the Infrared Camera (IRC) on board the AKARI satellite. Through comparison of the observed spectra with a theoretical model of deuterated PAH vibrational modes, the aromatic and (a)symmetric aliphatic C-D stretch modes were identified. We see emission features between 4.4-4.8 {\\mu}m, which could be unambiguously attributed to deuterated PAHs in only six of the observed sources, all of which are located in the Milky Way. In all cases, the aromatic C-D stretching feature is weaker than the aliphatic C-D stretching feature, and, in the case o...

  16. Noncomparative scaling of aromaticity through electron itinerancy

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Satadal [Department of Chemistry, University of North Bengal, Raja Rammohunpur, Darjeeling 734013, West Bengal (India); Darjeeling Polytechnic, Kurseong, Darjeeling 734203, West Bengal (India); Goswami, Tamal; Misra, Anirban, E-mail: anirbanmisra@yahoo.com [Department of Chemistry, University of North Bengal, Raja Rammohunpur, Darjeeling 734013, West Bengal (India)

    2015-10-15

    Aromaticity is a multidimensional concept and not a directly observable. These facts have always stood in the way of developing an appropriate theoretical framework for scaling of aromaticity. In the present work, a quantitative account of aromaticity is developed on the basis of cyclic delocalization of π-electrons, which is the phenomenon leading to unique features of aromatic molecules. The stabilization in molecular energy, caused by delocalization of π-electrons is obtained as a second order perturbation energy for archetypal aromatic systems. The final expression parameterizes the aromatic stabilization energy in terms of atom to atom charge transfer integral, onsite repulsion energy and the population of spin orbitals at each site in the delocalized π-electrons. An appropriate computational platform is framed to compute each and individual parameter in the derived equation. The numerical values of aromatic stabilization energies obtained for various aromatic molecules are found to be in close agreement with available theoretical and experimental reports. Thus the reliable estimate of aromaticity through the proposed formalism renders it as a useful tool for the direct assessment of aromaticity, which has been a long standing problem in chemistry.

  17. Aromatic plants play an important role in promoting soil biological activity related to nitrogen cycling in an orchard ecosystem.

    Science.gov (United States)

    Chen, Xinxin; Song, Beizhou; Yao, Yuncong; Wu, Hongying; Hu, Jinghui; Zhao, Lingling

    2014-02-15

    Aromatic plants can substantially improve the diversity and structure of arthropod communities, as well as reduce the number of herbivore pests and regulate the abundance of predators and parasitoids. However, it is not clear whether aromatic plants are also effective in improving soil quality by enhancing nutrient cycling. Here, field experiments are described involving intercropping with aromatic plants to investigate their effect on soil nitrogen (N) cycling in an orchard ecosystem. The results indicate that the soil organic nitrogen and available nitrogen contents increased significantly in soils intercropped with aromatic plants. Similarly, the activities of soil protease and urease increased, together with total microbial biomass involved in N cycling, including nitrifying bacteria, denitrifying bacteria and azotobacters, as well as the total numbers of bacteria and fungi. This suggests that aromatic plants improve soil N cycling and nutrient levels by enriching the soil in organic matter through the regulation of both the abundance and community structure of microorganisms, together with associated soil enzyme activity, in orchard ecosystems.

  18. Compactness Aromaticity of Atoms in Molecules

    Directory of Open Access Journals (Sweden)

    Mihai V. Putz

    2010-03-01

    Full Text Available A new aromaticity definition is advanced as the compactness formulation through the ratio between atoms-in-molecule and orbital molecular facets of the same chemical reactivity property around the pre- and post-bonding stabilization limit, respectively. Geometrical reactivity index of polarizability was assumed as providing the benchmark aromaticity scale, since due to its observable character; with this occasion new Hydrogenic polarizability quantum formula that recovers the exact value of 4.5 a03 for Hydrogen is provided, where a0 is the Bohr radius; a polarizability based–aromaticity scale enables the introduction of five referential aromatic rules (Aroma 1 to 5 Rules. With the help of these aromatic rules, the aromaticity scales based on energetic reactivity indices of electronegativity and chemical hardness were computed and analyzed within the major semi-empirical and ab initio quantum chemical methods. Results show that chemical hardness based-aromaticity is in better agreement with polarizability based-aromaticity than the electronegativity-based aromaticity scale, while the most favorable computational environment appears to be the quantum semi-empirical for the first and quantum ab initio for the last of them, respectively.

  19. Birds and polycyclic aromatic hydrocarbons

    Science.gov (United States)

    Albers, P.H.

    2006-01-01

    Polycyclic aromatic hydrocarbons (PAH) are present throughout the global environment and are produced naturally and by activities of humans. Effects of PAH on birds have been determined by studies employing egg injection, egg immersion, egg shell application, single and multiple oral doses, subcutaneous injection, and chemical analysis of field-collected eggs and tissue. The four-to six-ring aromatic compounds are the most toxic to embryos, young birds, and adult birds. For embryos, effects include death, developmental abnormalities, and a variety of cellular and biochemical responses. For adult and young birds, effects include reduced egg production and hatching, increased clutch or brood abandonment, reduced growth, increased organweights, and a variety of biochemical responses. Trophic level accumulation is unlikely. Environmental exposure to PAH in areas of high human population or habitats affected by recent petroleum spills might be sufficient to adversely affect reproduction. Evidence of long-term effects of elevated concentrations of environmental PAH on bird populations is very limited and the mechanisms of effect are unclear.

  20. Bleach vs. Bacteria

    Science.gov (United States)

    ... Articles | Inside Life Science Home Page Bleach vs. Bacteria By Sharon Reynolds Posted April 2, 2014 Your ... hypochlorous acid to help kill invading microbes, including bacteria. Researchers funded by the National Institutes of Health ...

  1. Hückel's Rule of Aromaticity Categorizes Aromatic Closo Boron Hydride Clusters

    OpenAIRE

    Poater i Teixidor, Jordi; Solà i Puig, Miquel; Viñas, Clara; Teixidor, Francesc

    2016-01-01

    A direct connection is established between tridimensional aromatic closo boron hydride clusters and planar aromatic [n]annulenes for medium and large size boron clusters. In particular, our results prove the existence of a link between the two-dimensional Hückel rule followed by aromatic [n]-annulenes and Wade-Mingos' rule of three-dimensional aromaticity applied to the aromatic [BnHn]2- closo boron hydride clusters. Our results show that closo boron hydride clusters can be categorized into d...

  2. Beyond organic chemistry: aromaticity in atomic clusters.

    Science.gov (United States)

    Boldyrev, Alexander I; Wang, Lai-Sheng

    2016-04-28

    We describe joint experimental and theoretical studies carried out collaboratively in the authors' labs for understanding the structures and chemical bonding of novel atomic clusters, which exhibit aromaticity. The concept of aromaticity was first discovered to be useful in understanding the square-planar unit of Al4 in a series of MAl4(-) bimetallic clusters that led to discoveries of aromaticity in many metal cluster systems, including transition metals and similar cluster motifs in solid compounds. The concept of aromaticity has been found to be particularly powerful in understanding the stability and bonding in planar boron clusters, many of which have been shown to be analogous to polycyclic aromatic hydrocarbons in their π bonding. Stimulated by the multiple aromaticity in planar boron clusters, a design principle has been proposed for stable metal-cerntered aromatic molecular wheels of the general formula, M@Bn(k-). A series of such borometallic aromatic wheel complexes have been produced in supersonic cluster beams and characterized experimentally and theoretically, including Ta@B10(-) and Nb@B10(-), which exhibit the highest coordination number in two dimensions.

  3. Heterogeneous photocatalytic reactions of sulfur aromatic compounds.

    Science.gov (United States)

    Samokhvalov, Alexander

    2011-11-18

    Sulfur aromatic compounds, such as mono-, di-, tri-, and tetraalkyl-substituted thiophene, benzothiophenes, dibenzothiophenes, are the molecular components of many fossils (petroleum, oil shale, tar sands, bitumen). Structural units of natural, cross-linked heteroaromatic polymers present in brown coals, turf, and soil are similar to those of sulfur aromatic compounds. Many sulfur aromatic compounds are found in the streams of petroleum refining and upgrading (naphthas, gas oils) and in the consumer products (gasoline, diesel, jet fuels, heating fuels). Besides fossils, the structural fragments of sulfur aromatic compounds are present in molecules of certain organic semiconductors, pesticides, small molecule drugs, and in certain biomolecules present in human body (pheomelanin pigments). Photocatalysis is the frontier area of physical chemistry that studies chemical reactions initiated by absorption of photons by photocatalysts, that is, upon electronic rather than thermal activation, under "green" ambient conditions. This review provides systematization and critical review of the fundamental chemical and physicochemical information on heterogeneous photocatalysis of sulfur aromatic compounds accumulated in the last 20-30 years. Specifically, the following topics are covered: physicochemical properties of sulfur aromatic compounds, major classes of heterogeneous photocatalysts, mechanisms and reactive intermediates of photocatalytic reactions of sulfur aromatic compounds, and the selectivity of these reactions. Quantum chemical calculations of properties and structures of sulfur aromatic compounds, their reactive intermediates, and the structure of adsorption complexes formed on the surface of the photocatalysts are also discussed.

  4. Intracellular Bacteria in Protozoa

    Science.gov (United States)

    Görtz, Hans-Dieter; Brigge, Theo

    Intracellular bacteria in humans are typically detrimental, and such infections are regarded by the patients as accidental and abnormal. In protozoa it seems obvious that many bacteria have coevolved with their hosts and are well adapted to the intracellular way of life. Manifold interactions between hosts and intracellular bacteria are found, and examples of antibacterial resistance of unknown mechanisms are observed. The wide diversity of intracellular bacteria in protozoa has become particularly obvious since they have begun to be classified by molecular techniques. Some of the bacteria are closely related to pathogens; others are responsible for the production of toxins.

  5. Removal of high-molecular weight polycyclic aromatic hydrocarbons

    Directory of Open Access Journals (Sweden)

    Ulrich Vasconcelos

    2011-01-01

    Full Text Available Alternatives for the removal of high-molecular weight polycyclic aromatic hydrocarbons (HWM-PAH from soil were tested by adding fertilizer or glycerol, as well as the combination of both. Experiments were carried out for 60 days in reactors containing a HWM-PAH-contaminated soil (8030 μg kg-1, accompanied by pH monitoring, humidity control and quantification of total heterotrophic bacteria and total fungus. Fertilizer addition removed 41.6% of HWM-PAH. Fertilizer and glycerol in combination removed 46.2%. When glycerol was added individually, degradation reached 50.4%. Glycerol also promoted the increase of degradation rate during the first 30 days suggesting the HMW-PAH removal occurred through cometabolic pathways.

  6. Conservation of medicinal and aromatic plants

    Directory of Open Access Journals (Sweden)

    Šveistytė, Laima

    2016-07-01

    Full Text Available The conservation of medicinal and aromatic plants includes ex situ and in situ methods. The genetic recourses of medicinal and aromatic plants are stored, studied and constantly maintained in the field collections of the Institute of Botany of Nature Research Centre, Kaunas Botanical Garden of Vytautas Magnus University and Aleksandras Stulginskis University of Agriculture. Presently seeds of 214 accessions representing 38 species of medicinal and aromatic plants are stored in a long-term storage in the Plant Gene Bank. The data about national genetic resources are collected and stored in the Central Database of the Plant Gene Bank.

  7. The effects of biodegradation on the compositions of aromatic hydrocarbons and maturity indicators in biodegraded oils from Liaohe Basin

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    By the aid of GC-MS technique,a series of sequentially biodegraded oils from Liaohe Basin have been analyzed. The results show that the concentrations and relative compositions of various aromatic compounds in the biodegraded crude oils will change with increasing biodegradation degree. The concentrations of alkyl naphthalenes,alkyl phenanthrenes,alkyl dibenzothiophene are decreased,and the concentration of triaromatic steroids will increase with increasing biodegradation degree in biodegraded oils. Those phenomena indicate that various aromatic compounds are more easily biodegraded by bacteria like other kinds of hydrocarbons such as alkanes,but different series of aromatic compounds have a varied ability to resistant to biodegradation. The ratios of dibenzothiophene to phenenthrene(DBTH/P) and methyl dibenzothiophene to methyl phenanthrene(MDBTH/MP) are related to the features of depositional environment for source rocks such as redox and ancient salinity. However,in biodegraded oils,the two ratios increase quickly with the increase of the biodegradation degree,indicating that they have lost their geochemical significance. In this case,they could not be used to evaluate the features of depositional environment. Methyl phenanthrene index,methyl phenanthrene ratio and methyl dibenzoyhiophene ratio are useful aromatic maturity indicators for the crude oils and the source rocks without vitrinite. But for biodegraded oils,those aromatic maturity indicators will be affected by biodegradation and decrease with the increase of the biodegradation degree. Therefore,those aromatic molecular maturity indicators could not be used for biodegraded oils.

  8. Pulse shape discrimination in non-aromatic plastics

    Energy Technology Data Exchange (ETDEWEB)

    Paul Martinez, H.; Pawelczak, Iwona; Glenn, Andrew M.; Leslie Carman, M.; Zaitseva, Natalia; Payne, Stephen

    2015-01-21

    Recently it has been demonstrated that plastic scintillators have the ability to distinguish neutrons from gamma rays by way of pulse shape discrimination (PSD). This discovery has lead to new materials and new capabilities. Here we report our work with the effects of aromatic, non-aromatic, and mixed aromatic/non-aromatic matrices have on the performance of PSD plastic scintillators.

  9. Genomics of Probiotic Bacteria

    Science.gov (United States)

    O'Flaherty, Sarah; Goh, Yong Jun; Klaenhammer, Todd R.

    Probiotic bacteria from the Lactobacillus and Bifidobacterium species belong to the Firmicutes and the Actinobacteria phylum, respectively. Lactobacilli are members of the lactic acid bacteria (LAB) group, a broadly defined family of microorganisms that ferment various hexoses into primarily lactic acid. Lactobacilli are typically low G + C gram-positive species which are phylogenetically diverse, with over 100 species documented to date. Bifidobacteria are heterofermentative, high G + C content bacteria with about 30 species of bifidobacteria described to date.

  10. [Enhanced bioremediation of coking plant soils contaminated with polycyclic aromatic hydrocarbons].

    Science.gov (United States)

    Lu, Xiao-Xia; Li, Xiu-Li; Ma, Jie; Wu, Shu-Ke; Chen, Chao-Qi; Wu, Wei

    2011-03-01

    Soil samples contaminated with polycyclic aromatic hydrocarbons (PAHs) were collected from Beijing Coking Plant. The purposes were to isolate PAHs degrading bacteria from the soils, determine their appropriate living condition, enrich them and apply them in the enhanced bioremediation of the contaminated soils. Using each of the 16 USEPA priority PAHs as the sole carbon source, PAHs degrading bacteria were isolated using the method of plate streaking and identified by genetic analysis. In total seven species of PAHs degrading bacteria were obtained. When mixed, these bacteria could degrade the 16 (2-6 cyclic) PAHs studied at appropriate concentrations. In the liquid medium, when the total concentration of the 16 PAHs (sigma PAH16) was 17 microg/mL, single bacteria could grow well and degrade the PAHs. However, when sigma PAH16 was 166 microg/mL, the growth and activity of either single PAHs degrading bacteria or a mixture of the seven PAHs degrading bacteria were inhibited. Aiming at the contaminated soils from Beijing coking plant, five treatments were performed, i.e., control (C), addition of nutrient (N), addition of nutrient and PAHs degrading bacteria (N + B), addition of nutrient and surfactant (N +S), addition of nutrient and PAHs degrading bacteria and surfactant (N + B + S). After five weeks of experiment, compared to the C treatment, the mean removal rate of the 16 PAHs in the N + B treatment was increased 32%, and the mean removal rate of the 16 PAHs in the N + B + S treatment was increased 46% (the mean removal rate of the 10 4-6 cyclic PAHs was increased 52%). The addition of PAHs degrading bacteria and surfactant could significantly enhance the degradation of PAHs in the soils. This study provides evidence for the enhanced bioremediation of PAHs contaminated soil for Beijing coking plant and other coking plants.

  11. Comments on Coulomb pairing in aromatic hydrocarbons

    CERN Document Server

    Huber, D L

    2013-01-01

    Recently reported anomalies in the double-photonionization spectra of aromatic molecules such as benzene, naphthalene, anthracene and coronene are attributed to Coulomb-pair resonances of pi electrons.

  12. Silicone elastomers with aromatic voltage stabilizers

    DEFF Research Database (Denmark)

    A Razak, Aliff Hisyam; Skov, Anne Ladegaard

    modifications. In order to increase the electrical breakdown strength of polymers for e.g. the cable industry, additives like aromatic voltage stabilizers are used. Earlier works on using voltage stabilizers in polymers have mainly focused on polyethylene with the purpose of reducing power loss for high voltage...... insulation cables.3–5 As an alternative to utilise additives as voltage stabilizers, grafting aromatic compounds to silicone backbones may overcome the common problem of insolubility of the aromatic voltage stabilizer in the silicone elastomers due to phase separation. Preventing phase separation during...... via hydrosilylation by a vinyl-functional crosslinker. The mechanism of electron-trapping by aromatic compounds grafted to silicone backbones in a crosslinked PDMS is illustrated in Fig. 1. The electrical breakdown strength, the storage modulus and the loss modulus of the elastomer were investigated...

  13. Graphite Oxide and Aromatic Amines : Size Matters

    NARCIS (Netherlands)

    Spyrou, Konstantinos; Calvaresi, Matteo; Diamanti, Evmorfi A. K.; Tsoufis, Theodoros; Gournis, Dimitrios; Rudolf, Petra; Zerbetto, Francesco

    2015-01-01

    Experimental and theoretical studies are performed in order to illuminate, for first time, the intercalation mechanism of polycyclic aromatic molecules into graphite oxide. Two representative molecules of this family, aniline and naphthalene amine are investigated. After intercalation, aniline molec

  14. Volatilisation of aromatic hydrocarbons from soil

    DEFF Research Database (Denmark)

    Lindhardt, B.; Christensen, T.H.

    1996-01-01

    The non-steady-state fluxes of aromatic hydrocarbons were measured in the laboratory from the surface of soils contaminated with coal tar Four soil samples from a former gasworks site were used for the experiments. The fluxes were quantified for 11 selected compounds, 4 mono- and 7 polycyclic...... aromatic hydrocarbons, for a period of up to 8 or 16 days. The concentrations of the selected compounds in the soils were between 0.2 and 3,100 mu g/g. The study included the experimental determination of the distribution coefficient of the aromatic hydrocarbons between the sorbed phase and the water under...... saturated conditions. The determined distribution coefficients showed that the aromatic hydrocarbons were more strongly sorbed to the total organic carbon including the coal tar pitch - by a factor of 8 to 25 - than expected for natural organic matter. The fluxes were also estimated using an analytical...

  15. Infrared Spectra of Polycyclic Aromatic Hydrocarbons (PAHs)

    Science.gov (United States)

    Bauschlicher, Charles W., Jr.; Bakes, E. L. O.

    2000-01-01

    We have computed the synthetic infrared spectra of some polycyclic aromatic hydrocarbons containing up to 54 carbon atoms. The species studied include ovalene, circumcoronene, dicoronylene, and hexabenzocoronene. We report spectra for anions, neutrals, cations, and multiply charged cations.

  16. The Industrial Reduction of Aromatic Nitro Compounds.

    Science.gov (United States)

    Gilbert, G.

    1980-01-01

    Describes methods for enriching an A-level chemistry course with a series of chemical company visits. The rationale is discussed for an emphasis of the visits on the industrial reduction of aromatic nitro compounds. (CS)

  17. Activity relationships for aromatic crown ethers

    CERN Document Server

    Wilson, M J

    1998-01-01

    This thesis involves an investigation of aromatic crown ethers and a study of their binding constants for alkali metals. The study was motivated by the current needs of the semiconductor industry to improve the scavenging of mobile ions from fabricated circuits. A number of aromatic crown ethers have been sulphonated in an attempt to improve their water solubility and cation binding activity. These materials have been extensively studied and their binding activity determined. In collaboration with a molecular modelling study, the effect of ionisable sulphonate groups on the macrocycles' behaviour has been investigated. The broader issue of the effect of substituents in aromatic crown ethers has also been studied with the preparation of a wide range of substituted crown ethers. The cation binding activity of these materials has been found to bear a simple relationship to the electron withdrawing nature of the aromatic substituents. This relationship can be accurately monitored using electronic charge densities...

  18. Dehydrogenative Aromatization of Saturated Aromatic Compounds by Graphite Oxide and Molecular Sieves

    Institute of Scientific and Technical Information of China (English)

    张轩; 徐亮; 王希涛; 马宁; 孙菲菲

    2012-01-01

    Graphite oxide (GO) has attracted much attention of material and catalysis chemists recently. Here we describe a combination of GO and molecular sieves for the dehydrogenative aromatization. GO prepared through improved Hummers method showed high oxidative activity in this reaction. Partially or fully saturated aromatic compounds were converted to their corresponding dehydrogenated aromatic products with fair to excellent conversions and selectivities. As both GO and molecular sieves are easily available, cheap, lowly toxic and have good tolerance to various functional groups, this reaction provides a facile approach toward aromatic compounds from their saturated precursors

  19. Thoughts on Optimization of Aromatic Feedstock

    Institute of Scientific and Technical Information of China (English)

    Cao Jian

    2002-01-01

    This article refers to four cases of process unit combinations with different throughputs of aromatics unit for production of 450 kt/a paraxylene at a certain petrochemical complex in order to against a representative case (provided with an 800-kt/a CCR unit and a 600-kt/a disproportionation unit) and the feasibility and advantage of using prolysis gasoline as aromatic feedstock is studied.

  20. Aromatic amines sources, environmental impact and remediation

    OpenAIRE

    Pereira, Luciana; Mondal, P. K.; Alves, M. M.

    2015-01-01

    Aromatic amines are widely used industrial chemicals as their major sources in the environment include several chemical industry sectors such as oil refining, synthetic polymers, dyes, adhesives, rubbers, perfume, pharmaceuticals, pesticides and explosives. They result also from diesel exhaust, combustion of wood chips and rubber and tobacco smoke. Some types of aromatic amines are generated during cooking, special grilled meat and fish, as well. The intensive use and production of these comp...

  1. Soil bacteria for remediation of polluted soils

    Energy Technology Data Exchange (ETDEWEB)

    Springael, D.; Bastiaens, L.; Carpels, M.; Mergaey, M.; Diels, L.

    1996-09-18

    Soil bacteria, specifically adapted to contaminated soils, may be used for the remediation of polluted soils. The Flemish research institute VITO has established a collection of bacteria, which were isolated from contaminated areas. This collection includes microbacteria degrading mineral oils (Pseudomonas sp., Acinetobacter sp. and others), microbacteria degrading polycyclic aromatic hydrocarbons (genera Sphingomonas and Mycobacterium), microbacteria degrading polychlorobiphenyls (genus Ralstonia and strains related to beta-Proteobacteria), and metal resistant bacteria with plasmid borne resistances to Cd, Zn, Ni, Co, Cu, Hg, and Cr. Bench-scale reactors were developed to investigate the industrial feasibility of bioremediation. Batch Stirred Tank Reactors were used to evaluate the efficiency of oil degraders. Soils, contaminated with non-ferrous metals, were treated using a Bacterial Metal Slurry Reactor. It was found that the reduction of the Cd concentration may vary strongly from sample to sample: reduction factors vary from 95 to 50%. Is was shown that Cd contained in metallic sinter and biologically unavailable Cd could not be removed.

  2. [Recent advances in Sphingobium sp. SYK-6 for lignin aromatic compounds degradation--a review].

    Science.gov (United States)

    Zhang, Xiaoyan; Peng, Xue; Masai, Eiji

    2014-08-01

    Lignin is complex heteropolymer produced from hydroxycinnamyl alcohols through radical coupling. In nature, white-rot fungi are assumed initially to attack native lignin and release lignin-derived-low-molecular-weight compounds, and soil bacteria play an importent role for completely degradation of these compounds. Study on the soil bacteria degrading lignin-derived-low-molecular-weight compounds will give way to understand how aromatic compounds recycle in nature, and to utilize lignin compounds as the renewable materials for valuable materials production. Sphingobium sp. SYK-6 that grows on lignin biphenyl (5,5'-dehydrodivanillate) had been isolated from pulp effluent in 1987. We have researched this bacterium more than 25 years, a serious aromatic metabolic pathway has been determined, and related genes have been isolated. As the complete genome sequence of SYK-6 has been opened to the public in 2012, the entire aromatic compounds degradation mechanisms become more clear. Main contents in our review cover: (1) genome information; (2) aryl metabolism; (3) biphenyl metabolism; (4) ferulate metabolism; (5) tetrahydrofolate-dependent O-demethylation system for lignin compound degrdation; (6) protocatechuate 4,5-cleavage pathway; (7) multiple pathways for 3-O-methylgallate metabolism.

  3. Isolation of Marine Polycyclic Aromatic Hydrocarbon (PAH)-Degrading Cycloclasticus Strains from the Gulf of Mexico and Comparison of Their PAH Degradation Ability with That of Puget Sound Cycloclasticus Strains

    OpenAIRE

    1998-01-01

    Phenanthrene- and naphthalene-degrading bacteria were isolated from four offshore and nearshore locations in the Gulf of Mexico by using a modified most-probable-number technique. The concentrations of these bacteria ranged from 102 to 106 cells per ml of wet surficial sediment in mildly contaminated and noncontaminated sediments. A total of 23 strains of polycyclic aromatic hydrocarbon (PAH)-degrading bacteria were obtained. Based on partial 16S ribosomal DNA sequences and phenotypic charact...

  4. Distribution and Geochemical Implication of Aromatic Hydrocarbons across the Meishan Permian-Triassic Boundary

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Aromatic compounds extracted from sedimentary rocks can reflect environmental conditions, organic sources and maturity. The aromatics, identified in association with mass extinction in particular, would provide a signature assisting our understanding of the causes of the biotic crisis. Aromatic hydrocarbons were fractionated from the total lipid extracts of 37 samples taken from the Permian Triassic boundary (beds 23 to 34) of section B at Meishan(煤山),Zhejiang(浙江)Province in South China. These aromatics were analyzed by using gas chromatography-mass spectrometry (GC-MS). Main compounds identified include naphthalene, phenanthrenes, fluorene, dibenzothiophene, dibenzofuran, fluoranthene, pyrene and some of their methyl homologues. The indices of methyl phenanthrene distribution fraction indicate the comparable maturity (within the oil window, 0.7% - 1.0% of the mean vitrinite reflectance) of the organic matter throughout the whole profile analyzed. The ratio of dibenzothiophene to phenanthrene (DBT/PHN) varies generally at a comparable pace with lithology. Significantly,a gradual decrease of this ratio was observed within bed 24 limestone, which is probably due to the variation of sedimentary environment. This change is in line with the drop in the carbon isotope composition of carbonate, the loss of the Changhsingian reef ecosystem, and the decrease of cyanobacteria abundance within the bacteria population. The coincidence of these records suggests a close relation between the biotic crisis and marine environmental conditions, and these records clearly show the onset of the biotic crisis prior to event bed 25.

  5. Engineering of a psychrophilic bacterium for the bioremediation of aromatic compounds.

    Science.gov (United States)

    Parrilli, Ermengilda; Papa, Rosanna; Tutino, Maria Luisa; Sannia, Giovanni

    2010-01-01

    Microbial degradation of aromatic hydrocarbons has been studied with the aim of developing applications for the removal of toxic compounds. Efforts have been directed toward the genetic manipulation of mesophilic bacteria to improve their ability to degrade pollutants, even though many pollution problems occur in sea waters and in effluents of industrial processes which are characterized by low temperatures. From these considerations the idea of engineering a psychrophilic microorganism for the oxidation of aromatic compounds was developed.In a previous paper it was demonstrated that the recombinant Antarctic Pseudoalteromonas haloplanktis TAC125 (PhTAC/tou) expressing a toluene-o-xylene monooxygenase (ToMO) is able to convert several aromatic compounds into corresponding catechols. In our work we improved the metabolic capability of PhTAC/tou cells by combining action of recombinant ToMO enzyme with that of the endogenous P. haloplanktis TAC125 laccase-like protein. This strategy allowed conferring new and specific degradative capabilities to a bacterium isolated from an unpolluted environment; indeed engineered PhTAC/tou cells are able to grow on aromatic compounds as sole carbon and energy sources. Our approach demonstrates the possibility to use the engineered psychrophilic bacterium for the bioremediation of chemically contaminated marine environments and/or cold effluents.

  6. How honey kills bacteria

    NARCIS (Netherlands)

    P.H.S. Kwakman; A.A. te Velde; L. de Boer; D. Speijer; C.M.J.E. Vandenbroucke-Grauls; S.A.J. Zaat

    2010-01-01

    With the rise in prevalence of antibiotic-resistant bacteria, honey is increasingly valued for its antibacterial activity. To characterize all bactericidal factors in a medical-grade honey, we used a novel approach of successive neutralization of individual honey bactericidal factors. All bacteria t

  7. Metallization of bacteria cells

    Institute of Scientific and Technical Information of China (English)

    黎向锋; 李雅芹; 蔡军; 张德远

    2003-01-01

    Bacteria cells with different standard shapes are well suited for use as templates for the fabrication of magnetic and electrically conductive microstructures. In this paper, metallization of bacteria cells is demonstrated by an electroless deposition technique of nickel-phosphorus initiated by colloid palladium-tin catalyst on the surfaces of Citeromyces matritensis and Bacillus cereus. The activated and metallized bacteria cells have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD). Results showed that both Citeromyces matritensis and Bacillus cereus had no deformation in shape after metallization; the metallized films deposited on the surfaces of bacteria cells are homogeneous in thickness and noncrystalline in phase structure. The kinetics of colloid palladium-tin solution and electroless plating on bacteria cells is discussed.

  8. Aromatic metabolism of filamentous fungi in relation to the presence of aromatic compounds in plant biomass.

    Science.gov (United States)

    Mäkelä, Miia R; Marinović, Mila; Nousiainen, Paula; Liwanag, April J M; Benoit, Isabelle; Sipilä, Jussi; Hatakka, Annele; de Vries, Ronald P; Hildén, Kristiina S

    2015-01-01

    The biological conversion of plant lignocellulose plays an essential role not only in carbon cycling in terrestrial ecosystems but also is an important part of the production of second generation biofuels and biochemicals. The presence of the recalcitrant aromatic polymer lignin is one of the major obstacles in the biofuel/biochemical production process and therefore microbial degradation of lignin is receiving a great deal of attention. Fungi are the main degraders of plant biomass, and in particular the basidiomycete white rot fungi are of major importance in converting plant aromatics due to their ability to degrade lignin. However, the aromatic monomers that are released from lignin and other aromatic compounds of plant biomass are toxic for most fungi already at low levels, and therefore conversion of these compounds to less toxic metabolites is essential for fungi. Although the release of aromatic compounds from plant biomass by fungi has been studied extensively, relatively little attention has been given to the metabolic pathways that convert the resulting aromatic monomers. In this review we provide an overview of the aromatic components of plant biomass, and their release and conversion by fungi. Finally, we will summarize the applications of fungal systems related to plant aromatics.

  9. Water-soluble constituents of caraway: aromatic compound, aromatic compound glucoside and glucides.

    Science.gov (United States)

    Matsumura, Tetsuko; Ishikawa, Toru; Kitajima, Junichi

    2002-10-01

    From the water-soluble portion of the methanolic extract of caraway (fruit of Carum carvi L.), an aromatic compound, an aromatic compound glucoside and a glucide were isolated together with 16 known compounds. Their structures were clarified as 2-methoxy-2-(4'-hydroxyphenyl)ethanol, junipediol A 2-O-beta-D-glucopyranoside and L-fucitol, respectively.

  10. Identification of non-regulated aromatic amines of toxicological concern which can be cleaved from azo dyes used in clothing textiles.

    Science.gov (United States)

    Brüschweiler, Beat J; Küng, Simon; Bürgi, Daniel; Muralt, Lorenz; Nyfeler, Erich

    2014-07-01

    Azo dyes in textiles may release aromatic amines after enzymatic cleavage by skin bacteria or after dermal absorption and metabolism in the human body. From the 896 azo dyes with known chemical structure in the available textile dyes database, 426 azo dyes (48%) can generate one or more of the 22 regulated aromatic amines in the European Union in Annex XVII of REACH. Another 470 azo dyes (52%) can be cleaved into exclusively non-regulated aromatic amines. In this study, a search for publicly available toxicity data on non-regulated aromatic amines was performed. For a considerable percentage of non-regulated aromatic amines, the toxicity database was found to be insufficient or non-existent. 62 non-regulated aromatic amines with available toxicity data were prioritized by expert judgment with objective criteria according to their potential for carcinogenicity, genotoxicity, and/or skin sensitization. To investigate the occurrence of azo dye cleavage products, 153 random samples of clothing textiles were taken from Swiss retail outlets and analyzed for 22 high priority non-regulated aromatic amines of toxicological concern. Eight of these 22 non-regulated aromatic amines of concern could be detected in 17% of the textile samples. In 9% of the samples, one or more of the aromatic amines of concern could be detected in concentrations >30 mg/kg, in 8% of the samples between 5 and 30 mg/kg. The highest measured concentration was 622 mg/kg textile. There is an obvious need to assess consumer health risks for these non-regulated aromatic amines and to fill this gap in the regulation of clothing textiles.

  11. The chemistry and beneficial bioactivities of carvacrol (4-isopropyl-2-methylphenol), a component of essential oils produced by aromatic plants and spices

    Science.gov (United States)

    Aromatic plants produce organic compounds that may be involved in the defense of plants against phytopathogenic insects, bacteria, fungi, and viruses. One of these compounds called carvacrol that is found in high concentrations in essential oils such as oregano has been reported to exhibit numerous...

  12. Antibiotics from predatory bacteria

    Directory of Open Access Journals (Sweden)

    Juliane Korp

    2016-03-01

    Full Text Available Bacteria, which prey on other microorganisms, are commonly found in the environment. While some of these organisms act as solitary hunters, others band together in large consortia before they attack their prey. Anecdotal reports suggest that bacteria practicing such a wolfpack strategy utilize antibiotics as predatory weapons. Consistent with this hypothesis, genome sequencing revealed that these micropredators possess impressive capacities for natural product biosynthesis. Here, we will present the results from recent chemical investigations of this bacterial group, compare the biosynthetic potential with that of non-predatory bacteria and discuss the link between predation and secondary metabolism.

  13. Thermochemical factors affecting the dehalogenation of aromatics.

    Science.gov (United States)

    Sadowsky, Daniel; McNeill, Kristopher; Cramer, Christopher J

    2013-12-17

    Halogenated aromatics are one of the largest chemical classes of environmental contaminants, and dehalogenation remains one of the most important processes by which these compounds are degraded and detoxified. The thermodynamic constraints of aromatic dehalogenation reactions are thus important for understanding the feasibility of such reactions and the redox conditions necessary for promoting them. Accordingly, the thermochemical properties of the (poly)fluoro-, (poly)chloro-, and (poly)bromobenzenes, including standard enthalpies of formation, bond dissociation enthalpies, free energies of reaction, and the redox potentials of Ar-X/Ar-H couples, were investigated using a validated density functional protocol combined with continuum solvation calculations when appropriate. The results highlight the fact that fluorinated aromatics stand distinct from their chloro- and bromo- counterparts in terms of both their relative thermodynamic stability toward dehalogenation and how different substitution patterns give rise to relevant properties, such as bond strengths and reduction potentials.

  14. [Darwin and bacteria].

    Science.gov (United States)

    Ledermann D, Walter

    2009-02-01

    As in 2009 the scientific world celebrates two hundreds years from the birthday of Charles Darwin and one hundred and fifty from the publication of The Origin of Species, an analysis of his complete work is performed, looking for any mention of bacteria. But it seems that the great naturahst never took knowledge about its existence, something rather improbable in a time when the discovery of bacteria shook the medical world, or he deliberately ignored them, not finding a place for such microscopic beings into his theory of evolution. But the bacteria badly affected his familiar life, killing scarlet fever one of his children and worsening to death the evolution of tuberculosis of his favourite Annie. Darwin himself could suffer the sickness of Chagas, whose etiological agent has a similar level to bacteria in the scale of evolution.

  15. Simultaneous catabolism of plant-derived aromatic compounds results in enhanced growth for members of the Roseobacter lineage.

    Science.gov (United States)

    Gulvik, Christopher A; Buchan, Alison

    2013-06-01

    Plant-derived aromatic compounds are important components of the dissolved organic carbon pool in coastal salt marshes, and their mineralization by resident bacteria contributes to carbon cycling in these systems. Members of the roseobacter lineage of marine bacteria are abundant in coastal salt marshes, and several characterized strains, including Sagittula stellata E-37, utilize aromatic compounds as primary growth substrates. The genome sequence of S. stellata contains multiple, potentially competing, aerobic ring-cleaving pathways. Preferential hierarchies in substrate utilization and complex transcriptional regulation have been demonstrated to be the norm in many soil bacteria that also contain multiple ring-cleaving pathways. The purpose of this study was to ascertain whether substrate preference exists in S. stellata when the organism is provided a mixture of aromatic compounds that proceed through different ring-cleaving pathways. We focused on the protocatechuate (pca) and the aerobic benzoyl coenzyme A (box) pathways and the substrates known to proceed through them, p-hydroxybenzoate (POB) and benzoate, respectively. When these two substrates were provided at nonlimiting carbon concentrations, temporal patterns of cell density, gene transcript abundance, enzyme activity, and substrate concentrations indicated that S. stellata simultaneously catabolized both substrates. Furthermore, enhanced growth rates were observed when S. stellata was provided both compounds simultaneously compared to the rates of cells grown singly with an equimolar concentration of either substrate alone. This simultaneous-catabolism phenotype was also demonstrated in another lineage member, Ruegeria pomeroyi DSS-3. These findings challenge the paradigm of sequential aromatic catabolism reported for soil bacteria and contribute to the growing body of physiological evidence demonstrating the metabolic versatility of roseobacters.

  16. Lipopolysaccharides in diazotrophic bacteria.

    Science.gov (United States)

    Serrato, Rodrigo V

    2014-01-01

    Biological nitrogen fixation (BNF) is a process in which the atmospheric nitrogen (N2) is transformed into ammonia (NH3) by a select group of nitrogen-fixing organisms, or diazotrophic bacteria. In order to furnish the biologically useful nitrogen to plants, these bacteria must be in constant molecular communication with their host plants. Some of these molecular plant-microbe interactions are very specific, resulting in a symbiotic relationship between the diazotroph and the host. Others are found between associative diazotrophs and plants, resulting in plant infection and colonization of internal tissues. Independent of the type of ecological interaction, glycans, and glycoconjugates produced by these bacteria play an important role in the molecular communication prior and during colonization. Even though exopolysaccharides (EPS) and lipochitooligosaccharides (LCO) produced by diazotrophic bacteria and released onto the environment have their importance in the microbe-plant interaction, it is the lipopolysaccharides (LPS), anchored on the external membrane of these bacteria, that mediates the direct contact of the diazotroph with the host cells. These molecules are extremely variable among the several species of nitrogen fixing-bacteria, and there are evidences of the mechanisms of infection being closely related to their structure.

  17. Lipopolysaccharides in diazotrophic bacteria

    Directory of Open Access Journals (Sweden)

    Rodrigo Vassoler Serrato

    2014-09-01

    Full Text Available Biological nitrogen fixation is a process in which the atmospheric nitrogen (N2 is transformed into ammonia (NH3 by a select group of nitrogen-fixing organisms, or diazotrophic bacteria. In order to furnish the biologically useful nitrogen to plants, these bacteria must be in constant molecular communication with their host plants. Some of these molecular plant-microbe interactions are very specific, resulting in a symbiotic relationship between the diazotroph and the host. Others are found between associative diazotrophs and plants, resulting in plant infection and colonization of internal tissues. Independent of the type of ecological interaction, glycans and glycoconjugates produced by these bacteria play an important role in the molecular communication prior and during colonization. Even though exopolysaccharides (EPS and lipochitooligosaccharides (LCO produced by diazotrophic bacteria and released onto the environment have their importance in the microbe-plant interaction, it is the lipopolysaccharides (LPS, anchored on the external membrane of these bacteria, that mediates the direct contact of the diazotroph with the host cells. These molecules are extremely variable among the several species of nitrogen fixing-bacteria, and there are evidences of the mechanisms of infection being closely related to their structure.

  18. Production of aromatics from di- and polyoxygenates

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Taylor; Blank, Brian; Jones, Casey; Woods, Elizabeth; Cortright, Randy

    2016-09-13

    Methods, catalysts, and reactor systems for producing in high yield aromatic chemicals and liquid fuels from a mixture of oxygenates comprising di- and polyoxygenates are disclosed. Also disclosed are methods, catalysts, and reactor systems for producing aromatic chemicals and liquid fuels from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like; and methods, catalysts, and reactor systems for producing the mixture of oxygenates from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like. The disclosed catalysts for preparing the mixture of oxygenates comprise a Group VIII metal and a crystalline alumina support.

  19. Production of aromatics from di- and polyoxygenates

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Taylor; Blank, Brian; Jones, Casey; Woods, Elizabeth; Cortright, Randy

    2016-08-02

    Methods, catalysts, and reactor systems for producing in high yield aromatic chemicals and liquid fuels from a mixture of oxygenates comprising di- and polyoxygenates are disclosed. Also disclosed are methods, catalysts, and reactor systems for producing aromatic chemicals and liquid fuels from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like; and methods, catalysts, and reactor systems for producing the mixture of oxygenates from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like. The disclosed catalysts for preparing the mixture of oxygenates comprise a Ni.sub.nSn.sub.m alloy and a crystalline alumina support.

  20. Global aromatics supply. Today and tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    Bender, M. [BASF SE, Ludwigshafen (Germany)

    2013-11-01

    Aromatics are the essential building blocks for some of the largest petrochemical products in today's use. To the vast majority they are consumed to produce intermediates for polymer products and, hence, contribute to our modern lifestyle. Their growth rates are expected to be in line with GDP growth in future. This contrasts the significantly lower growth rates of the primary sources for aromatics - fuel processing and steam cracking of naphtha fractions. A supply gap can be expected to open up in future for which creative solutions will be required. (orig.)

  1. Assessing aromaticity and the degree of aromatic condensation of pyrogenic carbon

    Science.gov (United States)

    Wiedemeier, D. B.; Abiven, S.; Hockaday, W. C.; Keiluweit, M.; Kleber, M.; Masiello, C. A.; McBeath, A. V.; Nico, P. S.; Pyle, L. A.; Schneider, M. P.; Smernik, R. J.; Wiesenberg, G. L.; Schmidt, M. W.

    2013-12-01

    Fire-derived, pyrogenic carbon (PyC) is a persistent organic carbon fraction in soils because it is relatively resistant against chemical and biological degradation. PyC thus represents a carbon sequestration potential in the global carbon cycle and was also reported to be potentially beneficial for soil fertility. PyC is naturally added to soils during wildfires and anthropogenically in the form of biochar, after organic waste is pyrolyzed. Aromaticity and the degree of aromatic condensation are the two main quality properties of PyC that probably determine its persistence against degradation. Consequently, the two properties largely influence the PyC's carbon sequestration potential as well as the duration, during which it can provide benefits to the soil. Aromaticity and the degree of aromatic condensation of PyC should theoretically be dependent on pyrolysis conditions, such as highest heating temperature or pyrolysis time, and also depend on the feedstock. In this study, we used two different pyrolysis procedures and four different feedstocks to produce four thermosequences of 38 chars in total, with highest heating temperatures ranging from 100 - 1000° C. The chars were then analyzed with an extensive suite of seven different methods: solid state 13C nuclear magnetic resonance (13C NMR), diffuse infrared Fourier transform spectroscopy (DRIFT), synchrotron-based near-edge X-ray absorption fine structure analysis (NEXAFS), benzene polycarboxylic acid analysis (BPCA), lipid analysis, elemental analysis and helium pycnometry. These methods allowed to infer the aromaticity and the degree of aromatic condensation of the differently pyrolyzed materials. Using multivariate statistical methods, aromaticity and the degree of aromatic condensation could successfully be linked to highest heating temperature and other pyrolysis conditions because characteristic patterns of the two aromatic properties could be observed by different methods throughout all four

  2. Fluorescence method for enzyme analysis which couples aromatic amines with aromatic aldehydes

    Science.gov (United States)

    Smith, R.E.; Dolbeare, F.A.

    1980-10-21

    Analysis of proteinases is accomplished using conventional amino acid containing aromatic amine substrates. Aromatic amines such as 4-methoxy-2-naphthylamine (4M2NA), 2-naphthylamine, aminoisophthalic acid dimethyl ester, p-nitroaniline, 4-methoxy-1-aminofluorene and coumarin derivatives resulting from enzymatic hydrolysis of the substrate couples with aromatic aldehydes such as 5-nitrosalicylaldehyde (5-NSA), benzaldehyde and p-nitrobenzaldehyde to produce Schiff-base complexes which are water insoluble. Certain Schiff-base complexes produce a shift from blue to orange-red (visible) fluorescence. Such complexes are useful in the assay of enzymes. No Drawings

  3. Fluorescence method for enzyme analysis which couples aromatic amines with aromatic aldehydes

    Science.gov (United States)

    Smith, Robert E.; Dolbeare, Frank A.

    1979-01-01

    Analysis of proteinases is accomplished using conventional amino acid containing aromatic amine substrates. Aromatic amines such as 4-methoxy-2-naphthylamine (4M2NA), 2-naphthylamine, aminoisophthalic acid dimethyl ester, p-nitroaniline, 5-methoxy-1-aminofluorene and coumarin derivatives resulting from enzymatic hydrolysis of the substrate couples with aromatic aldehydes such as 5-nitrosalicylaldehyde (5-NSA), benzaldehyde and p-nitrobenzaldehyde to produce Schiff-base complexes which are water insoluble. Certain Schiff-base complexes produce a shift from blue to orange-red (visible) fluorescence. Such complexes are useful in the assay of enzymes.

  4. [Preparation and antimicrobial effect of aromatic, natural and bacteriostatic foot wash with skin care].

    Science.gov (United States)

    Gao, Su-Hua; Zhao, Guo-Xiang; Yang, Xiao-Dong; Xu, Ling-Ling

    2013-06-01

    To prepare the aromatic, natural and bacteriostatic foot wash with skin care and research the inhibition effect on the different bacteria and pathogenic fungus which cause dermatophytosis. It was prepared by using Sophoraflavescens and Dictamnus dasycarpus as materials with the addition of Aloe extract, essential oil, surfactant, etc. The antifungal and antibacterial activity was researched by the levitation liquid quantitative method. The foot wash smelled faintly scent. The use of this product can produce a rich foam. The inhibitory rate were all more than 90%. The preparation process of the foot wash was simple. It has obviously bacteriostatic and fungistatic effect.

  5. Estuarine ecology of phenanthrene-degrading bacteria

    Science.gov (United States)

    Guerin, William F.; Jones, Galen E.

    1989-08-01

    Phenanthrene degrading bacteria were ubiquitously distributed in waters and sediments of the Great Bay Estuary, NH, as determined using a 14C-phenanthrene mineralization assay. Similar activities were observed in water samples collected in March and June when these were incubated at 18 °C even though ambient water temperatures were 1-4 °C and 10-22 °C, respectively. This observation indicated the constant presence of a mesophilic phenanthrene-degrading bacterial population in the estuary. Among water samples, the highest biodegradation activities were associated with samples collected downstream from a dredging operation which introduced high concentrations of coal tar PAH (polycyclic aromatic hydrocarbons) into the Cocheco River, and in areas receiving PAH from pleasure and commercial boating activities. Mid-estuarine maxima in biodegradation activity during both sampling trips suggested adaptation of the microbial flora to the salinities prevailing in the low turnover, high residence time portion of the Estuary at the time of sampling. Despite the hydrophobicity of phenanthrene, no correlation between biodegradation rates and particulate matter concentrations were observed. Similarly, concentrations of nutrients and dissolved and particulate organic matter correlated poorly with biodegradation rates. Better agreements between 14C-phenanthrene mineralization potentials and plate counts on a phenanthrene/toluene agar (PTA) medium were observed. Phenanthrene biodegradative activities and numbers of culturable bacteria growing on PTA were governed by the degree of previous exposure to PAH.

  6. The fecal bacteria

    Science.gov (United States)

    Sadowsky, Michael J.; Whitman, Richard L.

    2011-01-01

    The Fecal Bacteria offers a balanced, integrated discussion of fecal bacteria and their presence and ecology in the intestinal tract of mammals, in the environment, and in the food supply. This volume covers their use in examining and assessing water quality in order to offer protection from illnesses related to swimming in or ingesting contaminated water, in addition to discussing their use in engineering considerations of water quality, modeling, monitoring, and regulations. Fecal bacteria are additionally used as indicators of contamination of ready-to-eat foods and fresh produce. The intestinal environment, the microbial community structure of the gut microbiota, and the physiology and genomics of this broad group of microorganisms are explored in the book. With contributions from an internationally recognized group of experts, the book integrates medicine, public health, environmental, and microbiological topics in order to provide a unique, holistic understanding of fecal bacteria. Moreover, it shows how the latest basic science and applied research findings are helping to solve problems and develop effective management strategies. For example, readers will discover how the latest tools and molecular approaches have led to our current understanding of fecal bacteria and enabled us to improve human health and water quality. The Fecal Bacteria is recommended for microbiologists, clinicians, animal scientists, engineers, environmental scientists, food safety experts, water quality managers, and students. It will help them better understand fecal bacteria and use their knowledge to protect human and environmental health. They can also apply many of the techniques and molecular tools discussed in this book to the study of a broad range of microorganisms in a variety of habitats.

  7. RECOVERY OF URANIUM BY AROMATIC DITHIOCARBAMATE COMPLEXING

    Science.gov (United States)

    Neville, O.K.

    1959-08-11

    A selective complexing organic solvent extraction process is presented for the separation of uranium values from an aqueous nitric acid solution of neutron irradiated thorium. The process comprises contacting the solution with an organic aromatic dithiccarbamaie and recovering the resulting urancdithiccarbamate complex with an organic solvent such as ethyl acetate.

  8. Bacterial formation of hydroxylated aromatic compounds.

    NARCIS (Netherlands)

    Tweel, van den W.J.J.

    1988-01-01

    As stated in the introduction of this thesis, hydroxylated aromatic compounds in general are of great importance for various industries as for instance pharmaceutical, agrochemical and petrochemical industries. Since these compounds can not be isolated in sufficient amounts from natural resources, t

  9. THE POLYMERIZATION OF AROMATIC AND HETEROCYCLIC DINITRILES

    Institute of Scientific and Technical Information of China (English)

    HUANG Zhitang

    1988-01-01

    This review is a concise survey about the works in our laboratory on the polymerization of aromatic and heterocyclic dinitriles, including the polymerization kinetics and mechanism, synthesis of heterocyclic dinitriles, the structure of polymers, and the correlation between the structures of dinitriles and polymerization rates and thermal performances of polymers.

  10. Fused aromatic thienopyrazines: structure, properties and function

    KAUST Repository

    Mondal, Rajib

    2010-01-01

    Recent development of a fused aromatic thieno[3.4-b]pyrazine system and their application in optoelectronic devices are reviewed. Introduction of a fused aromatic unit followed by side chain engineering, dramatically enhanced the charge carrier mobility in thin film transistor devices and mobilities up to 0.2 cm2/Vs were achieved. The optoelectronic properties of these fused aromatic thienopyrazine polymers (Eg = 1.3 to 1.6 eV, HOMO = -4.9 to -5.2 V) were tuned by introduction of various fused aromatic rings within thienopyrazine. By balancing the fundamental properties of these polymers, both high charge carrier mobilities and moderate PCEs in solar cells were achieved. Further, effects of copolymerizing units are discussed. Low band gap semiconducting polymer (Eg ∼ 1 eV) with high field effect mobility (0.044 cm2/Vs) was obtained using cyclopentadithiophene as copolymerizing unit. Finally, a molecular design approach to enhance the absorption coefficients is discussed, which resulted in improved power conversion efficiency in bulk heterojunction solar cells. © 2010 The Royal Society of Chemistry.

  11. Fate and biodegradability of sulfonated aromatic amines

    NARCIS (Netherlands)

    Tan, N.C.G.; Leeuwen, van A.; Voorthuizen, van E.M.; Slenders, P.; Prenafeta, F.X.; Temmink, H.; Lettinga, G.; Field, J.A.

    2005-01-01

    Ten sulfonated aromatic amines were tested for their aerobic and anaerobic biodegradability and toxicity potential in a variety of environmental inocula. Of all the compounds tested, only two aminobenzenesulfonic acid (ABS) isomers, 2- and 4-ABS, were degraded. The observed degradation occurred only

  12. Electronic Aromaticity Index for Large Rings

    CERN Document Server

    Matito, Eduard

    2015-01-01

    We introduce a new electronic aromaticity index, AV1245, consisting in the average of the 4-center MCI values along the ring that keep a positional relationship of 1,2,4,5. AV1245 measures the extent of transferability of the delocalized electrons between bonds 1-2 and 4-5, which is expected to be large in conjugated circuits and, therefore, in aromatic molecules. A new algorithm for the calculation of MCI for large rings is also introduced and used to produce the data for the calibration of the new aromaticity index. AV1245 does not rely on reference values, does not suffer from large numerical precision errors, and it does not present any limitation on the nature of atoms, the molecular geometry or the level of calculation. It is a size-extensive measure with a small computational cost that grows linearly with the number of ring members. Therefore, it is specially suitable to study the aromaticity of large molecular rings as those occurring in belt-shaped M\\"obius structures or porphyrins.

  13. 40 CFR 721.2673 - Aromatic epoxide resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic epoxide resin (generic). 721... Substances § 721.2673 Aromatic epoxide resin (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aromatic epoxide resin (PMN...

  14. 40 CFR 721.5762 - Aromatic aldehyde phenolic resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic aldehyde phenolic resin... Specific Chemical Substances § 721.5762 Aromatic aldehyde phenolic resin (generic). (a) Chemical substance... aromatic aldehyde phenolic resin (PMN P-01-573) is subject to reporting under this section for...

  15. 40 CFR 721.2925 - Brominated aromatic ester.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Brominated aromatic ester. 721.2925... Substances § 721.2925 Brominated aromatic ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a brominated aromatic ester (PMN...

  16. Parsing of the free energy of aromatic-aromatic stacking interactions in solution

    Energy Technology Data Exchange (ETDEWEB)

    Kostjukov, Viktor V.; Khomytova, Nina M. [Department of Physics, Sevastopol National Technical University, Sevastopol 99053, Crimea (Ukraine); Hernandez Santiago, Adrian A.; Tavera, Anna-Maria Cervantes; Alvarado, Julieta Salas [Faculty of Chemical Sciences, Autonomous University of Puebla, Puebla (Mexico); Evstigneev, Maxim P., E-mail: max_evstigneev@mail.ru [Department of Physics, Sevastopol National Technical University, Sevastopol 99053, Crimea (Ukraine)

    2011-10-15

    Graphical abstract: Highlights: > A protocol for decomposition of the free energy of aromatic stacking is developed. > The factors stabilizing/destabilizing stacking of aromatic molecules are defined. > Hydrophobic contribution is found to be dominant. - Abstract: We report an analysis of the energetics of aromatic-aromatic stacking interactions for 39 non-covalent reactions of self- and hetero-association of 12 aromatic molecules with different structures and charge states. A protocol for computation of the contributions to the total energy from various energetic terms has been developed and the results are consistent with experiment in 92% of all the systems studied. It is found that the contributions from hydrogen bonds and entropic factors are always unfavorable, whereas contributions from van-der-Waals, electrostatic and/or hydrophobic effects may lead to stabilizing or destabilizing factors depending on the system studied. The analysis carried out in this work provides an answer to the questions 'What forces stabilize/destabilize the stacking of aromatic molecules in aqueous-salt solution and what are their relative importance?'

  17. Anaerobic bacteria in otitis media.

    Science.gov (United States)

    Fulghum, R S; Daniel, H J; Yarborough, J G

    1977-01-01

    Anaerobic bacteria, Peptostrepotococcus intermedius and Propionibacterium acnes, were found in mixed culture specimens from four to ten tested cases of chronic secretory otitis media. These anaerobic bacteria were in a mixed infection flora with aerobic bacteria most often Staphylococcus epidermidis and Cornybacterium sp. which do not fit any established species. The findings of anaerobic bacteria in otitis media is consistent with the sporadic report of the involvement of anaerobic bacteria in otitis media in the literature since 1898.

  18. Microwave-assisted synthesis of α-hydroxy aromatic ketones from α-bromo aromatic ketones in water

    Institute of Scientific and Technical Information of China (English)

    Xiang Liu; Hai Bo Chen; Zheng Guang Pan; Jian He Xu; He Xing Li

    2011-01-01

    A reaction of α-bromo aromatic ketones in water with microwave irradiation gave the corresponding α-hydroxy aromatic ketones in good yields.The use of microwaves was found to significantly improve yields and shorten the reaction time.This reaction afforded a very clean,convenient method for the synthesis of α-hydroxy aromatic ketones.

  19. Production of the flavor compound benzaldehyde by lactic acid bacteria: role of manganese and its transport systems in Lactobacillus plantarum

    NARCIS (Netherlands)

    Nierop Groot, M.N.

    2001-01-01

    One of the aims of the research described in this thesis (Chapter 1 and 2) was to investigate the conversion of phenylalanine to the aromatic flavor compound benzaldehyde in lactic acid bacteria (LAB) (Chapter 3). Lactobacillus plantarum was used as the model organism to study phenylalanine degradat

  20. Antimicrobial Effects of Several Essential Oil from Aromatic Plants

    Directory of Open Access Journals (Sweden)

    Felicia TUŢULESCU

    2016-12-01

    Full Text Available Essential oils (EOs have been long recognized for their antibacterial, antifungal, antiviral, insecticidal and antioxidant properties. The present research aimed to study the antimicrobial effects of some volatile oils from aromatic plants (sweet basil and dill against several microorganisms, namely Bacillus subtilis, Alternaria alternata and Penicillium expansum. The oils have been extracted through distillation procedures and the antimicrobial action of the oils was assessed through the disc diffusion method. The best effect against the Bacillus subtilis strain has occurred when the essential oil of dill was undiluted. Regarding the the Alternaria species, it was noted that dill volatile oil has acted in an efficient way only undiluted. As the oil's concentration decreased, the strain becomed resistant. The sweet basil oil has proven to be highly effective when acting against the Bacillus strain. By volatilization, the sweet basil oil produced a strong antimicrobial effect, even in control disc, in which it was noticed a small development of colonies comparing with the dill oil. The results indicated that the sweet basil essential oil exerted an antimicrobial effect both against the tested bacteria and moulds, while the dill oil had a great inhibitory action on Bacillus subtilis and Alternaria alternata, but was less efficient against Penicillium expansum.

  1. Monitoring the microbial community during solid-state acetic acid fermentation of Zhenjiang aromatic vinegar.

    Science.gov (United States)

    Xu, Wei; Huang, Zhiyong; Zhang, Xiaojun; Li, Qi; Lu, Zhenming; Shi, Jinsong; Xu, Zhenghong; Ma, Yanhe

    2011-09-01

    Zhenjiang aromatic vinegar is one of the most famous Chinese traditional vinegars. In this study, change of the microbial community during its fermentation process was investigated. DGGE results showed that microbial community was comparatively stable, and the diversity has a disciplinary series of changes during the fermentation process. It was suggested that domestication of microbes and unique cycle-inoculation style used in the fermentation of Zhenjiang aromatic vinegar were responsible for comparatively stable of the microbial community. Furthermore, two clone libraries were constructed. The results showed that bacteria presented in the fermentation belonged to genus Lactobacillus, Acetobacter, Gluconacetobacter, Staphylococcus, Enterobacter, Pseudomonas, Flavobacterium and Sinorhizobium, while the fungi were genus Saccharomyces. DGGE combined with clone library analysis was an effective and credible technique for analyzing the microbial community during the fermentation process of Zhenjiang aromatic vinegar. Real-time PCR results suggested that the biomass showed a "system microbes self-domestication" process in the first 5 days, then reached a higher level at the 7th day before gradually decreasing until the fermentation ended at the 20th day. This is the first report to study the changes of microbial community during fermentation process of Chinese traditional solid-state fermentation of vinegar.

  2. Enhancing trichloroethylene degradation using non-aromatic compounds as growth substrates.

    Science.gov (United States)

    Kim, Seungjin; Hwang, Jeongmin; Chung, Jinwook; Bae, Wookeun

    2014-06-30

    The effect of non-aromatic compounds on the trichloroethylene (TCE) degradation of toluene-oxidizing bacteria were evaluated using Burkholderia cepacia G4 that expresses toluene 2-monooxygenase and Pseudomonas putida that expresses toluene dioxygenase. TCE degradation rates for B. cepacia G4 and P. putida with toluene alone as growth substrate were 0.144 and 0.123 μg-TCE/mg-protein h, respectively. When glucose, acetate and ethanol were fed as additional growth substrates, those values increased up to 0.196, 0.418 and 0.530 μg-TCE/mg-protein h, respectively for B. cepacia G4 and 0.319, 0.219 and 0.373 μg-TCE/mg-protein h, respectively for P. putida. In particular, the addition of ethanol resulted in a high TCE degradation rate regardless of the initial concentration. The use of a non-aromatic compound as an additional substrate probably enhanced the TCE degradation because of the additional supply of NADH that is consumed in co-metabolic degradation of TCE. Also, it is expected that the addition of a non-aromatic substrate can reduce the necessary dose of toluene and, subsequently, minimize the potential competitive inhibition upon TCE co-metabolism by toluene.

  3. Mycophagous soil bacteria

    NARCIS (Netherlands)

    Rudnick, M.B.

    2015-01-01

    Abstract

    Soil microorganisms evolved several strategies to compete for limited nutrients in soil. Bacteria of the genus Collimonas developed a way to exploit fungi as a source of organic nutrients. This strategy has been termed “mycophagy&r

  4. Antibiotic-Resistant Bacteria.

    Science.gov (United States)

    Longenecker, Nevin E.; Oppenheimer, Dan

    1982-01-01

    A study conducted by high school advanced bacteriology students appears to confirm the hypothesis that the incremental administration of antibiotics on several species of bacteria (Escherichia coli, Staphylococcus epidermis, Bacillus sublitus, Bacillus megaterium) will allow for the development of antibiotic-resistant strains. (PEB)

  5. Bacteria-surface interactions.

    Science.gov (United States)

    Tuson, Hannah H; Weibel, Douglas B

    2013-05-14

    The interaction of bacteria with surfaces has important implications in a range of areas, including bioenergy, biofouling, biofilm formation, and the infection of plants and animals. Many of the interactions of bacteria with surfaces produce changes in the expression of genes that influence cell morphology and behavior, including genes essential for motility and surface attachment. Despite the attention that these phenotypes have garnered, the bacterial systems used for sensing and responding to surfaces are still not well understood. An understanding of these mechanisms will guide the development of new classes of materials that inhibit and promote cell growth, and complement studies of the physiology of bacteria in contact with surfaces. Recent studies from a range of fields in science and engineering are poised to guide future investigations in this area. This review summarizes recent studies on bacteria-surface interactions, discusses mechanisms of surface sensing and consequences of cell attachment, provides an overview of surfaces that have been used in bacterial studies, and highlights unanswered questions in this field.

  6. Aromatic characterization of pot distilled kiwi spirits.

    Science.gov (United States)

    López-Vázquez, Cristina; García-Llobodanin, Laura; Pérez-Correa, José Ricardo; López, Francisco; Blanco, Pilar; Orriols, Ignacio

    2012-03-07

    This study contributes fundamental knowledge that will help to develop a distillate of kiwi wine, made from kiwis of the Hayward variety grown in the southwest of Galicia (Spain). Two yeast strains, L1 (Saccharomyces cerevisiae ALB-6 from the EVEGA yeast collection) and L2 (S. cerevisiae Uvaferm BDX from Lallemand) were assessed to obtain a highly aromatic distillate. The kiwi spirits obtained were compared with other fruit spirits, in terms of higher alcohols, minor alcohols, monoterpenols, and other minor compounds, which are relevant in determining the quality and taste of the kiwi spirits. It was found that the kiwi juice fermented with yeast L1 produced a more aromatic distillate. In addition, kiwi distillates produced with both yeasts had the same ratio of trans-3-hexen-1-ol and cis-3-hexen-1-ol, which is lower than that found in other fruit distillates.

  7. Polyimides derived from non-aromatic monomers

    Energy Technology Data Exchange (ETDEWEB)

    Volksen, W.; Sanchez, M.I.; Cha, Hyuk-Jin; Yoon, D.Y. [IBM Almaden Research Center, San Jose, CA (United States)

    1995-12-01

    In recent years the shift in emphasis on high performance polymers, such as polyimides for microelectronic applications, has led to the search for other potential applications utilizing the unique properties of this class of polymers. In this context, polyimides incorporating non-aromatic units in the polymer backbone have been shown to exhibit excellent optical properties as well as significantly lower refractive indices. This lowering in the refractive index, of course, is also reflected in a lower dielectric constant of the material. For this reason, we have initiated a study of new polyimides, in which the traditional aromatic character is diluted with cycloaliphatic structures. One such example is the polyimide derived from hexafluoroisopropylidene diphthalic anhydride (6FDA) and 1,4-diaminocyclohexane (DACH). Preliminary data with respect to the preparation and solution behavior of the polyimide precursor as well as the characterization of relevant physical properties of the final polyimide will be presented.

  8. Side Chain Cyclized Aromatic Amino Acids

    DEFF Research Database (Denmark)

    Van der Poorten, Olivier; Knuhtsen, Astrid; Sejer Pedersen, Daniel

    2016-01-01

    Constraining the conformation of flexible peptides is a proven strategy to increase potency, selectivity, and metabolic stability. The focus has mostly been on constraining the backbone dihedral angles; however, the correct orientation of the amino acid side chains (χ-space) that constitute...... the peptide pharmacophore is equally important. Control of χ-space utilizes conformationally constrained amino acids that favor, disfavor, or exclude the gauche (-), the gauche (+), or the trans conformation. In this review we focus on cyclic aromatic amino acids in which the side chain is connected...... to the peptide backbone to provide control of χ(1)- and χ(2)-space. The manifold applications for cyclized analogues of the aromatic amino acids Phe, Tyr, Trp, and His within peptide medicinal chemistry are showcased herein with examples of enzyme inhibitors and ligands for G protein-coupled receptors....

  9. Aromatic compounds from three Brazilian Lauraceae species

    Energy Technology Data Exchange (ETDEWEB)

    Batista, Andrea Nastri de Luca; Batista Junior, Joao Marcos; Lopez, Silvia Noeli; Furlan, Maysa; Cavalheiro, Alberto Jose; Silva, Dulce Helena Siqueira; Bolzani, Vanderlan da Silva [UNESP, Araraquara, SP (Brazil). Inst. de Quimica. Dept. de Quimica Organica; Nunomura, Sergio Massayoshi [Instituto Nacional de Pesquisa da Amazonia (INPA), Manaus, AM (Brazil). Dept. de Produtos Naturais; Yoshida, Massayoshi [Centro de Biotecnologia da Amazonia, Manaus, AM (Brazil)

    2010-07-01

    Phytochemical investigations on three Brazilian Lauraceae species from the Cerrado region of Sao Paulo State, Ocotea corymbosa (Meins) Mez., O. elegans Mez. and Persea pyrifolia Nees and Mart. ex Nees resulted in the isolation of flavonoids, an ester of the 4-O-E-caffeoylquinic acid, an aromatic sesquiterpene besides furofuran lignans. This is the first chemical study on the leaves of Ocotea elegans and O. corymbosa as well as the first report of non-volatile compounds from Persea pyrifolia. (author)

  10. Allylation of Aromatic Aldehyde under Microwave Irradiation

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Yu-Mei; JIA,Xue-Feng; WANG,Jin-Xian

    2004-01-01

    @@ Allylation of carbonyl compounds is one of the most interesting processes for the preparation of homoallylic alcohols. Over the past few decades, many reagents have been developed for such reactions[1~3]. In this paper, we first report allylic zinc reagent 1, which can be prepared from zinc dust and allyl bromide conveniently in THF, and reacted with aromatic aldehyde to give homo-allylic alcohols under microwave irradiation.

  11. Aromatics Oxidation and Soot Formation in Flames

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J. B.; Richter, H.

    2005-03-29

    This project is concerned with the kinetics and mechanisms of aromatics oxidation and the growth process to polycyclic aromatic hydrocarbons (PAH) of increasing size, soot and fullerenes formation in flames. The overall objective of the experimental aromatics oxidation work is to extend the set of available data by measuring concentration profiles for decomposition intermediates such as phenyl, cyclopentadienyl, phenoxy or indenyl radicals which could not be measured with molecular-beam mass spectrometry to permit further refinement and testing of benzene oxidation mechanisms. The focus includes PAH radicals which are thought to play a major role in the soot formation process while their concentrations are in many cases too low to permit measurement with conventional mass spectrometry. The radical species measurements are used in critical testing and improvement of a kinetic model describing benzene oxidation and PAH growth. Thermodynamic property data of selected species are determined computationally, for instance using density functional theory (DFT). Potential energy surfaces are explored in order to identify additional reaction pathways. The ultimate goal is to understand the conversion of high molecular weight compounds to nascent soot particles, to assess the roles of planar and curved PAH and relationships between soot and fullerenes formation. The specific aims are to characterize both the high molecular weight compounds involved in the nucleation of soot particles and the structure of soot including internal nanoscale features indicative of contributions of planar and/or curved PAH to particle inception.

  12. Degradation of Polycyclic Aromatic Hydrocarbon Pyrene by Biosurfactant-Producing Bacteria Gordonia cholesterolivorans AMP 10

    OpenAIRE

    2016-01-01

    Pyrene degradation and biosurfactant activity by a new strain identified as Gordonia cholesterolivorans AMP 10 were studied. The strain grew well and produced effective biosurfactants in the presence of glucose, sucrose, and crude oil. The biosurfactants production was detected by the decreased surface tension of the medium and emulsification activity.  Analysis of microbial growth parameters showed that AMP10 grew best at 50 µg mL-1 pyrene concentration, leading to 96 % degradation of pyrene...

  13. Responses of the Microalga Chlorophyta sp. to Bacterial Quorum Sensing Molecules (N-Acylhomoserine Lactones): Aromatic Protein-Induced Self-Aggregation.

    Science.gov (United States)

    Zhou, Dandan; Zhang, Chaofan; Fu, Liang; Xu, Liang; Cui, Xiaochun; Li, Qingcheng; Crittenden, John C

    2017-03-21

    Bacteria and microalgae often coexist during the recycling of microalgal bioresources in wastewater treatment processes. Although the bacteria may compete with the microalgae for nutrients, they could also facilitate microalgal harvesting by forming algal-bacterial aggregates. However, very little is known about interspecies interactions between bacteria and microalgae. In this study, we investigated the responses of a model microalga, Chlorophyta sp., to the typical quorum sensing (QS) molecules N-acylhomoserine lactones (AHLs) extracted from activated sludge bacteria. Chlorophyta sp. self-aggregated in 200 μm bioflocs by secreting 460-1000 kDa aromatic proteins upon interacting with AHLs, and the settling efficiency of Chlorophyta sp. reached as high as 41%. However, Chlorophyta sp. cells were essentially in a free suspension in the absence of AHLs. Fluorescence intensity of the aromatic proteins had significant (P microalga. Transcriptome results further revealed up-regulation of synthesis pathways for aromatic proteins from tyrosine and phenylalanine that was assisted by anthranilate accumulation. To the best of our knowledge, this is the first study to confirm that eukaryotic microorganisms can sense and respond to prokaryotic QS molecules.

  14. Is Your ATM Dispensing Bacteria?

    Science.gov (United States)

    ... news/fullstory_162067.html Is Your ATM Dispensing Bacteria? Study in New York City found most of ... keypads in New York City were covered in bacteria, researchers reported, with most of the microbes coming ...

  15. Genomics of oral bacteria.

    Science.gov (United States)

    Duncan, Margaret J

    2003-01-01

    Advances in bacterial genetics came with the discovery of the genetic code, followed by the development of recombinant DNA technologies. Now the field is undergoing a new revolution because of investigators' ability to sequence and assemble complete bacterial genomes. Over 200 genome projects have been completed or are in progress, and the oral microbiology research community has benefited through projects for oral bacteria and their non-oral-pathogen relatives. This review describes features of several oral bacterial genomes, and emphasizes the themes of species relationships, comparative genomics, and lateral gene transfer. Genomics is having a broad impact on basic research in microbial pathogenesis, and will lead to new approaches in clinical research and therapeutics. The oral microbiota is a unique community especially suited for new challenges to sequence the metagenomes of microbial consortia, and the genomes of uncultivable bacteria.

  16. Manufacture of Probiotic Bacteria

    Science.gov (United States)

    Muller, J. A.; Ross, R. P.; Fitzgerald, G. F.; Stanton, C.

    Lactic acid bacteria (LAB) have been used for many years as natural biopreservatives in fermented foods. A small group of LAB are also believed to have beneficial health effects on the host, so called probiotic bacteria. Probiotics have emerged from the niche industry from Asia into European and American markets. Functional foods are one of the fastest growing markets today, with estimated growth to 20 billion dollars worldwide by 2010 (GIA, 2008). The increasing demand for probiotics and the new food markets where probiotics are introduced, challenges the industry to produce high quantities of probiotic cultures in a viable and stable form. Dried concentrated probiotic cultures are the most convenient form for incorporation into functional foods, given the ease of storage, handling and transport, especially for shelf-stable functional products. This chapter will discuss various aspects of the challenges associated with the manufacturing of probiotic cultures.

  17. Exopolysaccharides from Marine Bacteria

    Institute of Scientific and Technical Information of China (English)

    CHI Zhenming; FANG Yan

    2005-01-01

    Microbial polysaccharides represent a class of important products of growing interest for many sectors of industry. In recent years, there has been a growing interest in isolating new exopolysaccharides (EPSs)-producing bacteria from marine environments, particularly from various extreme marine environments. Many new marine microbial EPSs with novel chemical compositions, properties and structures have been found to have potential applications in fields such as adhesives,textiles, pharmaceuticals and medicine for anti-cancer, food additives, oil recovery and metal removal in mining and industrial waste treatments, etc This paper gives a brief summary of the information about the EPSs produced by marine bacteria,including their chemical compositions, properties and structures, together with their potential applications in industry.

  18. Bacterial community changes with N'-N' dimethylforamide (DMF) additives during polycyclic aromatic hydrocarbons (PAH) biodegardation.

    Science.gov (United States)

    Chang, Y T; Lee, J F; Chao, H P; Liao, W L

    2006-01-01

    This study examined the changes in the bacterial community during biodegradation of polycyclic aromatic hydrocarbon (PAH) substrate when N'-N' dimethylformamide (DMF) was added. The microbial populations that biodegrade the PAH substrate were assessed by Fluorescence in-situ hybridization (FISH) and changed from 49.45% Archaea and 49.15% Bacteria to 42.00% Archaea and 51.78% Bacteria when the PAH was supplemented with DMF. Nine microorganisms were classified as Gram-negative alpha-, beta- and gamma-Proteobacteria bacteria during biodegradation of PAH alone by the Biolog system. Incentive eleven microorganisms obtained from the PAH-DMF mixed substrate were found to be beta-, gamma-Proteobacteria bacteria, high G+C Gram-positive bacteria (HGC), low G+C Gram-positive bacteria (LGC) and there was even one Deinococcus-Thermus strain; this indicates greater biodiversity. The numbers in the Pseudomonad group were as high as 10(5)-10(6) CFU ml(-1), suggesting that this group plays an important role in PAH biodegradation. Community-Level Physiological Profiling (CLPP) and physiological characterization were different in the PAH biodegradation process with and without DMF. Utilization of the 95 carbon sources from the Biolog GN2 microtiter plate was greater during PAH biodegradation when PAH is present alone compared to that in the presence of DMF. The range of enzymatic activities during PAH biodegradation was lower in the presence of DMF. These results show that DMF should be used with caution when PAH is a substrate during laboratory or pilot biotreatability studies.

  19. Cable Bacteria in Freshwater Sediments

    OpenAIRE

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus B.; Dittmer, Anders Lindequist; Bjerg, Jesper Tataru; Trojan, Daniela; Schreiber, Lars; Damgaard, Lars Riis; Schramm, Andreas; Nielsen, Lars Peter

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the fre...

  20. 'Rare biosphere' bacteria as key phenanthrene degraders in coastal seawaters.

    Science.gov (United States)

    Sauret, Caroline; Séverin, Tatiana; Vétion, Gilles; Guigue, Catherine; Goutx, Madeleine; Pujo-Pay, Mireille; Conan, Pascal; Fagervold, Sonja K; Ghiglione, Jean-François

    2014-11-01

    By coupling DNA-SIP and pyrosequencing approaches, we identified Cycloclasticus sp. as a keystone degrader of polycyclic aromatic hydrocarbons (PAH) despite being a member of the 'rare biosphere' in NW Mediterranean seawaters. We discovered novel PAH-degrading bacteria (Oceanibaculum sp., Sneathiella sp.) and we identified other groups already known to possess this function (Alteromonas sp., Paracoccus sp.). Together with Cycloclasticus sp., these groups contributed to potential in situ phenanthrene degradation at a rate >0.5 mg l(-1) day(-1), sufficient to account for a considerable part of PAH degradation. Further, we characterized the PAH-tolerant bacterial communities, which were much more diverse in the polluted site by comparison to unpolluted marine references. PAH-tolerant bacteria were also members of the rare biosphere, such as Glaciecola sp. Collectively, these data show the complex interactions between PAH-degraders and PAH-tolerant bacteria and provide new insights for the understanding of the functional ecology of marine bacteria in polluted waters.

  1. Immobilized Native Bacteria as a Tool for Bioremediation of Soils and Waters: Implementation and Modeling

    Directory of Open Access Journals (Sweden)

    C. Lobo

    2002-01-01

    Full Text Available Based on 3,4-dihydroxyphenylacetate (3,4-DHPA dioxygenase amino acid sequence and DNA sequence data for homologous genes, two different oligonucleotides were designed. These were assayed to detect 3,4-DHPA related aromatic compound—degrading bacteria in soil samples by using the FISH method. Also, amplification by PCR using a set of ERIC primers was assayed for the detection of Pseudomonas GCH1 strain, which used in the soil bioremediation process. A model was developed to understand and predict the behavior of bacteria and pollutants in a bioremediation system, taking into account fluid dynamics, molecular/cellular scale processes, and biofilm formation.

  2. Microarray and real-time PCR analyses of the responses of high-arctic soil bacteria to hydrocarbon pollution and bioremediation treatments.

    Science.gov (United States)

    Yergeau, Etienne; Arbour, Mélanie; Brousseau, Roland; Juck, David; Lawrence, John R; Masson, Luke; Whyte, Lyle G; Greer, Charles W

    2009-10-01

    High-Arctic soils have low nutrient availability, low moisture content, and very low temperatures and, as such, they pose a particular problem in terms of hydrocarbon bioremediation. An in-depth knowledge of the microbiology involved in this process is likely to be crucial to understand and optimize the factors most influencing bioremediation. Here, we compared two distinct large-scale field bioremediation experiments, located at the Canadian high-Arctic stations of Alert (ex situ approach) and Eureka (in situ approach). Bacterial community structure and function were assessed using microarrays targeting the 16S rRNA genes of bacteria found in cold environments and hydrocarbon degradation genes as well as quantitative reverse transcriptase PCR targeting key functional genes. The results indicated a large difference between sampling sites in terms of both soil microbiology and decontamination rates. A rapid reorganization of the bacterial community structure and functional potential as well as rapid increases in the expression of alkane monooxygenases and polyaromatic hydrocarbon-ring-hydroxylating dioxygenases were observed 1 month after the bioremediation treatment commenced in the Alert soils. In contrast, no clear changes in community structure were observed in Eureka soils, while key gene expression increased after a relatively long lag period (1 year). Such discrepancies are likely caused by differences in bioremediation treatments (i.e., ex situ versus in situ), weathering of the hydrocarbons, indigenous microbial communities, and environmental factors such as soil humidity and temperature. In addition, this study demonstrates the value of molecular tools for the monitoring of polar bacteria and their associated functions during bioremediation.

  3. Biodegradation of Mixed PAHs by PAH-Degrading Endophytic Bacteria.

    Science.gov (United States)

    Zhu, Xuezhu; Ni, Xue; Waigi, Michael Gatheru; Liu, Juan; Sun, Kai; Gao, Yanzheng

    2016-08-09

    Endophytic bacteria can promote plant growth, induce plant defence mechanisms, and increase plant resistance to organic contaminants. The aims of the present study were to isolate highly PAH-degrading endophytic bacteria from plants growing at PAH-contaminated sites and to evaluate the capabilities of these bacteria to degrade polycyclic aromatic hydrocarbons (PAHs) in vitro, which will be beneficial for re-colonizing target plants and reducing plant PAH residues through the inoculation of plants with endophytic bacteria. Two endophytic bacterial strains P₁ (Stenotrophomonas sp.) and P₃ (Pseudomonas sp.), which degraded more than 90% of phenanthrene (PHE) within 7 days, were isolated from Conyza canadensis and Trifolium pretense L., respectively. Both strains could use naphthalene (NAP), PHE, fluorene (FLR), pyrene (PYR), and benzo(a)pyrene (B(a)P) as the sole sources of carbon and energy. Moreover, these bacteria reduced the contamination of mixed PAHs at high levels after inoculation for 7 days; strain P₁ degraded 98.0% NAP, 83.1% FLR, 87.8% PHE, 14.4% PYR, and 1.6% B(a)P, and strain P₃ degraded 95.3% NAP, 87.9% FLR, 90.4% PHE, 6.9% PYR, and negligible B(a)P. Notably, the biodegradation of PAHs could be promoted through additional carbon and nitrogen nutrients; therein, beef extract was suggested as the optimal co-substrate for the degradation of PAHs by these two strains (99.1% PHE was degraded within 7 days). Compared with strain P₁, strain P₃ has more potential for the use in the removal of PAHs from plant tissues. These results provide a novel perspective in the reduction of plant PAH residues in PAH-contaminated sites through inoculating plants with highly PAH-degrading endophytic bacteria.

  4. Biodegradation of Mixed PAHs by PAH-Degrading Endophytic Bacteria

    Directory of Open Access Journals (Sweden)

    Xuezhu Zhu

    2016-08-01

    Full Text Available Endophytic bacteria can promote plant growth, induce plant defence mechanisms, and increase plant resistance to organic contaminants. The aims of the present study were to isolate highly PAH-degrading endophytic bacteria from plants growing at PAH-contaminated sites and to evaluate the capabilities of these bacteria to degrade polycyclic aromatic hydrocarbons (PAHs in vitro, which will be beneficial for re-colonizing target plants and reducing plant PAH residues through the inoculation of plants with endophytic bacteria. Two endophytic bacterial strains P1 (Stenotrophomonas sp. and P3 (Pseudomonas sp., which degraded more than 90% of phenanthrene (PHE within 7 days, were isolated from Conyza canadensis and Trifolium pretense L., respectively. Both strains could use naphthalene (NAP, PHE, fluorene (FLR, pyrene (PYR, and benzo(apyrene (B(aP as the sole sources of carbon and energy. Moreover, these bacteria reduced the contamination of mixed PAHs at high levels after inoculation for 7 days; strain P1 degraded 98.0% NAP, 83.1% FLR, 87.8% PHE, 14.4% PYR, and 1.6% B(aP, and strain P3 degraded 95.3% NAP, 87.9% FLR, 90.4% PHE, 6.9% PYR, and negligible B(aP. Notably, the biodegradation of PAHs could be promoted through additional carbon and nitrogen nutrients; therein, beef extract was suggested as the optimal co-substrate for the degradation of PAHs by these two strains (99.1% PHE was degraded within 7 days. Compared with strain P1, strain P3 has more potential for the use in the removal of PAHs from plant tissues. These results provide a novel perspective in the reduction of plant PAH residues in PAH-contaminated sites through inoculating plants with highly PAH-degrading endophytic bacteria.

  5. DIVERSIDAD DE BACTERIAS CULTIVABLES DE LA COSTA DE CALETA OLIVIA, PATAGONIA, ARGENTINA Diversity Of Cultivable Bacteria From The Coast Of Caleta Olivia, Patagonia , Argentina

    Directory of Open Access Journals (Sweden)

    GRACIELA PUCCI

    microcosms contained 5 g or 50 mL of samples with 0.01% of gasoline, and 0.1% of kerosene, diesel, crude oil and mineral oils. The CO2 was measured by titration. Four cultural medium were used i.e. BBR, BRN, mineral medium with crude oil and gas oil and ENDO for coliforms. The bacteria were identified by Sherlock - MIDI . The mineralization shows good values. The counts resulted negative to total coliforms and faecal coliforms. 403 strains were analyzed; the system could identify 172 strains in 32 genera in only 50 species. The rest of strains were not found in Sherlock data base (version 6.0. Pseudoalteromonas was the genus that was more frequently isolated. The summer and autumn seasons presented more quantity of biodiversity genera. We found genera, which are mentioned as hydrocarbon degrading genera in the literature.

  6. Extracellular polymeric substances govern the development of biofilm and mass transfer of polycyclic aromatic hydrocarbons for improved biodegradation.

    Science.gov (United States)

    Zhang, Yinping; Wang, Fang; Zhu, Xiaoshu; Zeng, Jun; Zhao, Qiguo; Jiang, Xin

    2015-10-01

    The hypothesis that extracellular polymeric substances (EPS) affect the formation of biofilms for subsequent enhanced biodegradation of polycyclic aromatic hydrocarbons was tested. Controlled formation of biofilms on humin particles and biodegradation of phenanthrene and pyrene were performed with bacteria and EPS-extracted bacteria of Micrococcus sp. PHE9 and Mycobacterium sp. NJS-P. Bacteria without EPS extraction developed biofilms on humin, in contrast the EPS-extracted bacteria could not attach to humin particles. In the subsequent biodegradation of phenanthrene and pyrene, the biodegradation rates by biofilms were significantly higher than those of EPS-extracted bacteria. Although, both the biofilms and EPS-extracted bacteria showed increases in EPS contents, only the EPS contents in biofilms displayed significant correlations with the biodegradation efficiencies of phenanthrene and pyrene. It is proposed that the bacterial-produced EPS was a key factor to mediate bacterial attachment to other surfaces and develop biofilms, thereby increasing the bioavailability of poorly soluble PAH for enhanced biodegradation.

  7. Long-term performance and stability of a continuous granular airlift reactor treating a high-strength wastewater containing a mixture of aromatic compounds.

    Science.gov (United States)

    Ramos, Carlos; Suárez-Ojeda, María Eugenia; Carrera, Julián

    2016-02-13

    Continuous feeding operation of an airlift reactor and its inoculation with mature aerobic granules allowed the successful treatment of a mixture of aromatic compounds (p-nitrophenol, o-cresol and phenol). Complete biodegradation of p-nitrophenol, o-cresol, phenol and their metabolic intermediates was achieved at an organic loading rate of 0.61 g COD L(-1)d(-1). Stable granulation was obtained throughout the long-term operation (400 days) achieving an average granule size of 2.0 ± 1 mm and a sludge volumetric index of 26 ± 1 mL g(-1) TSS. The identified genera in the aerobic granular biomass were heterotrophic bacteria able to consume aromatic compounds. Therefore, the continuous feeding regimen and the exposure of aerobic granules to a mixture of aromatic compounds make possible to obtain good granulation and high removal efficiency.

  8. Spectrometric study of α-methylene aromatic araminenone and aminoketone

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Thirteen α-methylene aromatic araminenone and four α-methylene aromatic aminoketones were prepared by modified Mannich reaction. On the basis of isotopic labeling, a plausible way of cleavage was proposed for the formation of the M+- 17 fragment peak in the MS of the α-methylene aromatic araminenone and aminoketones. The characteristic chemical shift of the olefinic protons in 1H NMR is also discussed.

  9. Monobromination of Activated Aromatic Compounds withPolyvinylbenzyltriphenylphosphonium Supported Tribromide

    Institute of Scientific and Technical Information of China (English)

    WU Ming-Hu; YANG Gui-Chun; CHEN Zu-Xing

    2001-01-01

    Chloromethylated crosslinked co-polyvinylbenzene-divinylber-zene (2% DVB) was treated with triphenylphospbhie and then with sodium bromate and hydrobromic acid to afford red col-ored insoluble polyvinylbenzyltriphenylphosphon supportedtribromide.This reagent could be used as a mild and efficient monobrominating reagent for activated aromatic compounds such as phenols,aromatic,aromatic amines and acety-lanilines with good yields and high para-selectivity.

  10. Biosurfactant produced by novel Pseudomonas sp. WJ6 with biodegradation of n-alkanes and polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Xia, Wenjie; Du, Zhifeng; Cui, Qingfeng; Dong, Hao; Wang, Fuyi; He, Panqing; Tang, YongChun

    2014-07-15

    Alkanes and polycyclic aromatic hydrocarbons (PAHs) have threatened the environment due to toxicity and poor bioavailability. Interest in degradation of these hazardous materials by biosurfactant-producing bacteria has been steadily increasing in recent years. In this work, a novel biosurfactant-producing Pseudomonas sp. WJ6 was isolated to degrade a wide range of n-alkanes and polycyclic aromatic hydrocarbons. Production of lipopeptide biosurfactant was observed in all biodegradable studies. These lipopeptides were purified and identified by C18 RP-HPLC system and electrospray ionization-mass spectrometry. Results of structural analysis showed that these lipopeptides generated from different hydrocarbons were classified to be surfactin, fengycin and lichenysin. Heavy-oil sludge washing experiments demonstrated that lipopeptides produced by Pseudomonas sp. WJ6 have 92.46% of heavy-oil washing efficiency. The obtained results indicate that this novel bacterial strain and its lipopeptides have great potentials in the environmental remediation and petroleum recovery.

  11. Phenylnaphthalenes: sublimation equilibrium, conjugation, and aromatic interactions.

    Science.gov (United States)

    Lima, Carlos F R A C; Rocha, Marisa A A; Schröder, Bernd; Gomes, Lígia R; Low, John N; Santos, Luís M N B F

    2012-03-22

    In this work, the interplay between structure and energetics in some representative phenylnaphthalenes is discussed from an experimental and theoretical perspective. For the compounds studied, the standard molar enthalpies, entropies and Gibbs energies of sublimation, at T = 298.15 K, were determined by the measurement of the vapor pressures as a function of T, using a Knudsen/quartz crystal effusion apparatus. The standard molar enthalpies of formation in the crystalline state were determined by static bomb combustion calorimetry. From these results, the standard molar enthalpies of formation in the gaseous phase were derived and, altogether with computational chemistry at the B3LYP/6-311++G(d,p) and MP2/cc-pVDZ levels of theory, used to deduce the relative molecular stabilities in various phenylnaphthalenes. X-ray crystallographic structures were obtained for some selected compounds in order to provide structural insights, and relate them to energetics. The thermodynamic quantities for sublimation suggest that molecular symmetry and torsional freedom are major factors affecting entropic differentiation in these molecules, and that cohesive forces are significantly influenced by molecular surface area. The global results obtained support the lack of significant conjugation between aromatic moieties in the α position of naphthalene but indicate the existence of significant electron delocalization when the aromatic groups are in the β position. Evidence for the existence of a quasi T-shaped intramolecular aromatic interaction between the two outer phenyl rings in 1,8-di([1,1'-biphenyl]-4-yl)naphthalene was found, and the enthalpy of this interaction quantified on pure experimental grounds as -(11.9 ± 4.8) kJ·mol(-1), in excellent agreement with the literature CCSD(T) theoretical results for the benzene dimer.

  12. Aromatic plant production on metal contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Zheljazkov, Valtcho D. [Mississippi State, Department of Plant and Soil Sciences and North Mississippi Research and Extension Center, 5421 Highway 145 South, Verona, MS 38879 (United States)], E-mail: vj40@pss.msstate.edu; Craker, Lyle E.; Xing Baoshan [Department of Plant and Soil Sciences, 12 Stockbridge Hall, University of Massachusetts, Amherst, MA 01003 (United States); Nielsen, Niels E. [Plant Nutrition and Soil Fertility Lab, Department of Agricultural Sciences, Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK1871, Copenhagen (Denmark); Wilcox, Andrew [Harper Adams University College, Newport, Shropshire, TF10 8NB (United Kingdom)

    2008-06-01

    Field and container experiments were conducted to assess the feasibility of growing aromatic crops in metal contaminated areas and the effect of metals on herbage and oil productivity. The field experiments were conducted in the vicinities of the Non-Ferrous Metals Combine (Zn-Cu smelter) near Plovdiv, Bulgaria using coriander, sage, dill, basil, hyssop, lemon balm, and chamomile grown at various distances from the smelter. Herbage essential oil yields of basil, chamomile, dill, and sage were reduced when they were grown closer to the smelter. Metal removal from the site with the harvestable plant parts was as high as 180 g ha{sup -1} for Cd, 660 g ha{sup -1} for Pb, 180 g ha{sup -1} for Cu, 350 g ha{sup -1} for Mn, and 205 g ha{sup -1} for Zn. Sequential extraction of soil demonstrated that metal fractionation was affected by the distance to the smelter. With decreasing distance to the smelter, the transfer factor (TF) for Cu and Zn decreased but increased for Cd, while the bioavailability factor (BF) for Cd, Pb, Cu, Mn, and Zn decreased. Scanning electron microscopy and X-ray microanalyses of contaminated soil verified that most of the Pb, Cd, Mn, Cu, and Zn were in the form of small (< 1 {mu}m) particles, although there were larger particles (1-5 {mu}m) with high concentrations of individual metals. This study demonstrated that high concentrations of heavy metals in soil or growth medium did not result in metal transfer into the essential oil. Of the tested metals, only Cu at high concentrations may reduce oil content. Our results demonstrated that aromatic crops may not have significant phytoremediation potential, but growth of these crops in metal contaminated agricultural soils is a feasible alternative. Aromatic crops can provide economic return and metal-free final product, the essential oil.

  13. Metabolism of aromatic compounds by Caulobacter crescentus

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, D.K.; Bourquin, A.W.

    1987-05-01

    Cultures of Caulobacter crescentus were found to grow on a variety of aromatic compounds. Degradation of benzoate, p-hydroxybenzoate, and phenol was found to occur via ..beta..-ketoadipate. The induction of degradative enzymes such as benzoate 1,2-dioxygenase, the ring cleavage enzyme catechol 1,2-dioxygenase, and cis,cis-muconate lactonizing enzyme appeared similar to the control mechanism present in Pseudomonas spp. Both benzoate 1,2-dioxygenase and catechol 1,2-dioxygenase had stringent specificities, as revealed by their action toward substituted benzoates and substituted catechols, respectively.

  14. Aromatics oxidation and soot formation in flames

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J.B.; Pope, C.J.; Shandross, R.A.; Yadav, T. [Massachusetts Institute of Technology, Cambridge (United States)

    1993-12-01

    This project is concerned with the kinetics and mechanisms of aromatics oxidation and soot and fullerenes formation in flames. The scope includes detailed measurements of profiles of stable and radical species concentrations in low-pressure one-dimensional premixed flames. Intermediate species identifications and mole fractions, fluxes, and net reaction rates calculated from the measured profiles are used to test postulated reaction mechanisms. Particular objectives are to identify and to determine or confirm rate constants for the main benzene oxidation reactions in flames, and to characterize fullerenes and their formation mechanisms and kinetics.

  15. Photoinduced dynamics in protonated aromatic amino acid

    CERN Document Server

    Grégoire, Gilles; Barat, Michel; Fayeton, Jacqueline; Dedonder-Lardeux, Claude; Jouvet, Christophe

    2008-01-01

    UV photoinduced fragmentation of protonated aromatics amino acids have emerged the last few years, coming from a situation where nothing was known to what we think a good understanding of the optical properties. We will mainly focus this review on the tryptophan case. Three groups have mostly done spectroscopic studies and one has mainly been involved in dynamics studies of the excited states in the femtosecond/picosecond range and also in the fragmentation kinetics from nanosecond to millisecond. All these data, along with high level ab initio calculations, have shed light on the role of the different electronic states of the protonated molecules upon the fragmentation mechanisms.

  16. Selection of ionic liquids for the extraction of aromatic hydrocarbons from aromatic/aliphatic mixtures

    NARCIS (Netherlands)

    Meindersma, G. Wytze; Podt, Anita (J.G.); Haan, de André B.

    2005-01-01

    The separation of aromatic hydrocarbons (benzene, toluene, ethyl benzene and xylenes) from C4 to C10 aliphatic hydrocarbon mixtures is challenging since these hydrocarbons have boiling points in a close range and several combinations form azeotropes. In this work, we investigated the separation of t

  17. Brotes germinados y bacterias

    OpenAIRE

    García Olmedo, Francisco

    2011-01-01

    Ante la confusión y el revuelo asociados al último incidente causado por una cepa de la bacteria Escherichia coli (E. coli) en Alemania, tal vez no esté de más esta carta para recordar y actualizar escritos míos anteriores aparecidos en Revista de Libros sobre los riesgos alimentarios en general y sobre los peligros de dicho microorganismo en particular. 1 . Aunque es cierto que la proporción de cepas peligrosas de E. coli es quizás inferior a la de delincuentes entre los humanos, exi...

  18. BACTERIA OF NOCАRDIA GENUS AS OBJECT OF BIOTECHNOLOGY

    Directory of Open Access Journals (Sweden)

    T. P. Pirog

    2013-06-01

    Full Text Available The literature and own experimental data, concerning biotechnological potential of bacteria of Nocаrdia genus are given. The use of these microorganisms as destructors of aliphatic (octane, pentadecanol, eicosane, octacosane, hexatriacontane, pristane, aromatic (phenol, octylbenzene, phenanthrene, anthracene, nitroaromatic (4-nitrophenol, heterocyclic (pyridine, ?-picoline hydrocarbons is described. The prospects of use of Nocаrdia in processes of substances bio-transformation (production of daidzein, ibuprofen, nicotinic acid and synthesis of some valuable metabolites, in particular antimicrobial and cytotoxic substances (ayamycin, transvalencin А, nocathiacin, brasilibactin A, nocaracins etc. as well as substances with surface-active and emulsifying properties are discussed. The own experimental data concerning optimization of cultivation conditions and intensification of surfactant synthesis on glycerol (byproduct of biodiesel production by oil oxidizing bacteria strain Nocardia vaccinii K-8, that was isolated from oil polluted samples of soil are presented. The ability of strain K-8 to assimilate some aromatic compounds (phenol, benzene, toluene, naphthalene, hexachlorbenzene, sulfanilic acid and N-phenylanthranilic acid, 0.3–0.5% was determined. It was shown that the highest oil destruction degree (94–98% in polluted water (2.6 g/L was achieved in the case of treatment with suspension of N. vaccinii K-8 cells (9.8 x 107 CFU/mL after 30 days, while surfactant preparation of post fermentative cultural liquid (100–300 mL/kg was more effective for remediation (destruction of 74–83% of oil of oil polluted soil (20 g/kg. It was determined that surfactants (0.085–0.85 mg/mL and other exocellular metabolites of strain К-8 possess antimicrobial activity against some phytopathogen bacteria of Pseudomonas and Xanthomonas strains. In this connection the quantity of living cells decreased by 80–100% after the treatment with the

  19. Multicenter bond index analysis of influence of metal cations on the aromaticity of aromatic amino acids: Phenylalanine and tyrosine

    Science.gov (United States)

    Pakiari, A. H.; Farrokhnia, M.; Azami, S. M.

    2008-05-01

    In order to provide insight into the influence of metal cations on the aromaticity of amino acids, evaluation of six-center delocalization indices is accomplished in the context of quantum theory of atoms in molecules (QTAIM). Aromaticity of two amino acids, phenylalanine and tyrosine, is investigated as typical amino acids containing aromatic ring in their isolated state and complexed by some metal cations. The results showed that the metal cations affect the most important three connectivities differently. Also, it is shown that the existence of metal cations can increase two-center delocalization in certain parts of the aromatic rings.

  20. Biodegradation aspects of polycyclic aromatic hydrocarbons (PAHs): a review.

    Science.gov (United States)

    Haritash, A K; Kaushik, C P

    2009-09-30

    PAHs are aromatic hydrocarbons with two or more fused benzene rings with natural as well as anthropogenic sources. They are widely distributed environmental contaminants that have detrimental biological effects, toxicity, mutagenecity and carcinogenicity. Due to their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity, the PAHs have gathered significant environmental concern. Although PAH may undergo adsorption, volatilization, photolysis, and chemical degradation, microbial degradation is the major degradation process. PAH degradation depends on the environmental conditions, number and type of the microorganisms, nature and chemical structure of the chemical compound being degraded. They are biodegraded/biotransformed into less complex metabolites, and through mineralization into inorganic minerals, H(2)O, CO(2) (aerobic) or CH(4) (anaerobic) and rate of biodegradation depends on pH, temperature, oxygen, microbial population, degree of acclimation, accessibility of nutrients, chemical structure of the compound, cellular transport properties, and chemical partitioning in growth medium. A number of bacterial species are known to degrade PAHs and most of them are isolated from contaminated soil or sediments. Pseudomonas aeruginosa, Pseudomons fluoresens, Mycobacterium spp., Haemophilus spp., Rhodococcus spp., Paenibacillus spp. are some of the commonly studied PAH-degrading bacteria. Lignolytic fungi too have the property of PAH degradation. Phanerochaete chrysosporium, Bjerkandera adusta, and Pleurotus ostreatus are the common PAH-degrading fungi. Enzymes involved in the degradation of PAHs are oxygenase, dehydrogenase and lignolytic enzymes. Fungal lignolytic enzymes are lignin peroxidase, laccase, and manganese peroxidase. They are extracellular and catalyze radical formation by oxidation to destabilize bonds in a molecule. The biodegradation of PAHs has been observed under both aerobic and anaerobic conditions and the rate

  1. Biodegradation aspects of Polycyclic Aromatic Hydrocarbons (PAHs): A review

    Energy Technology Data Exchange (ETDEWEB)

    Haritash, A.K., E-mail: akharitash@gmail.com [Department of Environmental Science and Engineering, Guru Jambheshwar University of Science and Technology, Hisar, Haryana (India); Kaushik, C.P. [Department of Environmental Science and Engineering, Guru Jambheshwar University of Science and Technology, Hisar, Haryana (India)

    2009-09-30

    PAHs are aromatic hydrocarbons with two or more fused benzene rings with natural as well as anthropogenic sources. They are widely distributed environmental contaminants that have detrimental biological effects, toxicity, mutagenecity and carcinogenicity. Due to their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity, the PAHs have gathered significant environmental concern. Although PAH may undergo adsorption, volatilization, photolysis, and chemical degradation, microbial degradation is the major degradation process. PAH degradation depends on the environmental conditions, number and type of the microorganisms, nature and chemical structure of the chemical compound being degraded. They are biodegraded/biotransformed into less complex metabolites, and through mineralization into inorganic minerals, H{sub 2}O, CO{sub 2} (aerobic) or CH{sub 4} (anaerobic) and rate of biodegradation depends on pH, temperature, oxygen, microbial population, degree of acclimation, accessibility of nutrients, chemical structure of the compound, cellular transport properties, and chemical partitioning in growth medium. A number of bacterial species are known to degrade PAHs and most of them are isolated from contaminated soil or sediments. Pseudomonas aeruginosa, Pseudomons fluoresens, Mycobacterium spp., Haemophilus spp., Rhodococcus spp., Paenibacillus spp. are some of the commonly studied PAH-degrading bacteria. Lignolytic fungi too have the property of PAH degradation. Phanerochaete chrysosporium, Bjerkandera adusta, and Pleurotus ostreatus are the common PAH-degrading fungi. Enzymes involved in the degradation of PAHs are oxygenase, dehydrogenase and lignolytic enzymes. Fungal lignolytic enzymes are lignin peroxidase, laccase, and manganese peroxidase. They are extracellular and catalyze radical formation by oxidation to destabilize bonds in a molecule. The biodegradation of PAHs has been observed under both aerobic and anaerobic conditions

  2. Self-assembly of aromatic-functionalized amphiphiles: The role and consequences of aromatic-aromatic noncovalent interactions in building supramolecular aggregates and novel assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Whitten, D.G.; Chen, L.; Geiger, H.C.; Perlstein, J.; Song, X. [Los Alamos National Lab., NM (United States). Chemical Science and Technology Div.]|[Univ. of Rochester, NY (United States)

    1998-12-10

    This feature article presents an overview of a study of several different aromatic-functionalized amphiphiles-fatty acid and phospholipid derivatives. These amphiphiles form organized assemblies when the fatty acids are spread as monolayers at the air-water interface or when the phospholipids are dispersed in aqueous solutions. For a wide range of aromatic chromophores--trans-stilbene derivatives and a series of vinylogues (1,4-diphenyl-1,3-butadiene and 1,6-diphenyl-1,3,5-hexatriene), diphenylacetylenes, and azobenzenes such as phenyl, biphenyl, and terphenyl derivatives and modified stilbenes (styryl thiophenes and styryl naphthalenes)--assembly formation is accompanied by formation of aggregates of the aromatic groups. Results of experimental studies and simulations indicate that in many cases the aromatics form a small, stable unit aggregate characterized by strong noncovalent edge-to-face interactions among adjacent aromatics. Although the unit aggregates exhibit characteristic spectral shifts and strong induced circular dichroism indicating a chiral pinwheel aggregate structure, they may be packed together in pure films or dispersions to form an extended glide or herringbone structure. Although the pinwheel unit aggregate and the extended glide or herringbone structure. Although the pinwheel unit aggregate and the extended glide structure is favored for the majority of aromatics studied, for certain aromatics (styrenes, styrylthiophenes, and {alpha}-styrylnaphthalenes) a translation layer, characterized by face-to-face noncovalent interactions, is preferred. The glide or herringbone aggregates are readily distinguished from the translation aggregates by different spectral signatures and different photochemical and photophysical behavior. Factors controlling the type of aggregate and hence extended structure formed from different aromatic functionalized aromatics include shape and steric factors and strength of the competing noncovalent edge-face and face

  3. Beneficial bacteria inhibit cachexia.

    Science.gov (United States)

    Varian, Bernard J; Goureshetti, Sravya; Poutahidis, Theofilos; Lakritz, Jessica R; Levkovich, Tatiana; Kwok, Caitlin; Teliousis, Konstantinos; Ibrahim, Yassin M; Mirabal, Sheyla; Erdman, Susan E

    2016-03-15

    Muscle wasting, known as cachexia, is a debilitating condition associated with chronic inflammation such as during cancer. Beneficial microbes have been shown to optimize systemic inflammatory tone during good health; however, interactions between microbes and host immunity in the context of cachexia are incompletely understood. Here we use mouse models to test roles for bacteria in muscle wasting syndromes. We find that feeding of a human commensal microbe, Lactobacillus reuteri, to mice is sufficient to lower systemic indices of inflammation and inhibit cachexia. Further, the microbial muscle-building phenomenon extends to normal aging as wild type animals exhibited increased growth hormone levels and up-regulation of transcription factor Forkhead Box N1 [FoxN1] associated with thymus gland retention and longevity. Interestingly, mice with a defective FoxN1 gene (athymic nude) fail to inhibit sarcopenia after L. reuteri therapy, indicating a FoxN1-mediated mechanism. In conclusion, symbiotic bacteria may serve to stimulate FoxN1 and thymic functions that regulate inflammation, offering possible alternatives for cachexia prevention and novel insights into roles for microbiota in mammalian ontogeny and phylogeny.

  4. Chemical communication in bacteria

    Science.gov (United States)

    Suravajhala, Srinivasa Sandeep; Saini, Deepak; Nott, Prabhu

    Luminescence in Vibrio fischeri is a model for quorum-sensing-gene-regulation in bacteria. We study luminescence response of V. fischeri to both internal and external cues at the single cell and population level. Experiments with ES114, a wild-type strain, and ainS mutant show that luminescence induction in cultures is not always proportional to cell-density and there is always a basal level of luminescence. At any given concentration of the exogenously added signals, C6-HSL and C8-HSL, luminescence per cell reaches a maximum during the exponential phase and decreases thereafter. We hypothesize that (1) C6-HSL production and LuxR activity are not proportional to cell-density, and (2) there is a shift in equilibrium from C6-HSL to C8-HSL during the later stages of growth of the culture. RT-PCR analysis of luxI and luxR shows that the expression of these genes is maximum corresponding to the highest level of luminescence. The shift in equilibrium is shown by studying competitive binding of C6-HSL and C8-HSL to LuxR. We argue that luminescence is a unicellular behaviour, and an intensive property like per cell luminescence is more important than gross luminescence of the population in understanding response of bacteria to chemical signalling. Funding from the Department of Science and Technology, India is acknowledged.

  5. Biodegradation of Polycyclic Aromatic Hydrocarbons in Mangrove Sediments Under Different Strategies: Natural Attenuation, Biostimulation, and Bioaugmentation with Rhodococcus erythropolis T902.1

    OpenAIRE

    Lang, F. S.; Destain, Jacqueline; Delvigne, Frank; Druart, P.; Ongena, Marc; Thonart, Philippe

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are pollutants that occur in mangrove sediments. Their removal by bacteria often depends on specific characteristics as the number of benzene rings they possess and their solubility. Their removal also depends on environmental factors, such as pH, temperature, oxygen, and the ability of the endogenous or exogenous microflora to metabolize hydrocarbons. With the aim of treating mangrove sediments polluted by hydrocarbons in a biological way, a biodegrada...

  6. Biodegradation of Polycyclic Aromatic Hydrocarbons in Mangrove Sediments Under Different Strategies: Natural Attenuation, Biostimulation, and Bioaugmentation with Rhodococcus erythropolis T902.1

    OpenAIRE

    Semboung Lang, Firmin; Destain, Jacqueline; Delvigne, Frank; Druart, Philippe; Ongena, Marc; Thonart, Philippe

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are pollutants that occur in mangrove sediments. Their removal by bacteria often depends on specific characteristics as the number of benzene rings they possess and their solubility. Their removal also depends on environmental factors, such as pH, temperature, oxygen, and the ability of the endogenous or exogenous microflora to metabolize hydrocarbons.With the aim of treating mangrove sediments polluted by hydrocarbons in a biolo...

  7. Enzyme catalytic nitration of aromatic compounds.

    Science.gov (United States)

    Kong, Mingming; Wang, Kun; Dong, Runan; Gao, Haijun

    2015-06-01

    Nitroaromatic compounds are important intermediates in organic synthesis. The classic method used to synthesize them is chemical nitration, which involves the use of nitric acid diluted in water or acetic acid, both harmful to the environment. With the development of green chemistry, environmental friendly enzyme catalysis is increasingly employed in chemical processes. In this work, we adopted a non-aqueous horseradish peroxidase (HRP)/NaNO2/H2O2 reaction system to study the structural characteristics of aromatic compounds potentially nitrated by enzyme catalysis, as well as the relationship between the charges on carbon atoms in benzene ring and the nitro product distribution. Investigation of various reaction parameters showed that mild reaction conditions (ambient temperature and neutral pH), plus appropriate use of H2O2 and NaNO2 could prevent inactivation of HRP and polymerization of the substrates. Compared to aqueous-organic co-solvent reaction media, the aqueous-organic two-liquid phase system had great advantages in increasing the dissolved concentration of substrate and alleviating substrate inhibition. Analysis of the aromatic compounds' structural characteristics indicated that substrates containing substituents of NH2 or OH were readily catalyzed. Furthermore, analysis of the relationship between natural bond orbital (NBO) charges on carbon atoms in benzene ring, as calculated by the density functional method, and the nitro product distribution characteristics, demonstrated that the favored nitration sites were the ortho and para positions of substituents in benzene ring, similar to the selectivity of chemical nitration.

  8. An Aromatic Inventory of the Local Volume

    CERN Document Server

    Marble, A R; van Zee, L; Dale, D A; Smith, J D T; Gordon, K D; Wu, Y; Lee, J C; Kennicutt, R C; Skillman, E D; Johnson, L C; Block, M; Calzetti, D; Cohen, S A; Lee, H; Schuster, M D

    2010-01-01

    Using infrared photometry from the Spitzer Space Telescope, we perform the first inventory of aromatic feature emission (AFE, but also commonly referred to as PAH emission) for a statistically complete sample of star-forming galaxies in the local volume. The photometric methodology involved is calibrated and demonstrated to recover the aromatic fraction of the IRAC 8 micron flux with a standard deviation of 6% for a training set of 40 SINGS galaxies (ranging from stellar to dust dominated) with both suitable mid-infrared Spitzer IRS spectra and equivalent photometry. A potential factor of two improvement could be realized with suitable 5.5 and 10 micron photometry, such as what may be provided in the future by JWST. The resulting technique is then applied to mid-infrared photometry for the 258 galaxies from the Local Volume Legacy (LVL) survey, a large sample dominated in number by low-luminosity dwarf galaxies for which obtaining comparable mid-infrared spectroscopy is not feasible. We find the total LVL lum...

  9. Catalytic C-H imidation of aromatic cores of functional molecules: ligand-accelerated Cu catalysis and application to materials- and biology-oriented aromatics.

    Science.gov (United States)

    Kawakami, Takahiro; Murakami, Kei; Itami, Kenichiro

    2015-02-25

    Versatile imidation of aromatic C-H bonds was accomplished. In the presence of copper bromide and 6,6'-dimethyl-2,2'-bipyridyl, a range of aromatics, such as polycyclic aromatic hydrocarbons, aromatic bowls, porphyrins, heteroaromatics, and natural products, can be imidated by N-fluorobenzenesulfonimide. A dramatic ligand-accelerated copper catalysis and an interesting kinetic profile were uncovered.

  10. Application of FT-IR spectroscopy for control of the medium composition during the biodegradation of nitro aromatic compounds.

    Science.gov (United States)

    Grube, Mara; Muter, Olga; Strikauska, Silvija; Gavare, Marita; Limane, Baiba

    2008-11-01

    Previous studies showed that cabbage leaf extract (CLE) added to the growth medium can noticeably promote the degradation of nitro aromatic compounds by specific consortium of bacteria upon their growth. For further development of the approach for contaminated soil remediation it was necessary to evaluate the qualitative and/or quantitative composition of different origin CLE and their relevance on the growth of explosives-degrading bacteria. Six CLE (different by species, cultivars and harvesting time) were tested and used as additives to the growth medium. It was shown that nitro aromatic compounds can be identified in the FT-IR absorption spectra by the characteristic band at 1,527 cm(-1), and in CLE by the characteristic band at 1,602 cm(-1). The intensity of the CLE band at 1,602 cm(-1) correlated with the concentration of total nitrogen (R2=0.87) and decreased upon the growth of bacteria. The content of nitrogen in CLE differed (0.22-1.00 vol.%) and significantly influenced the content of total carbohydrates (9.50-16.00% DW) and lipids [3.90-9.90% dry weight (DW)] accumulated in bacterial cells while the content of proteins was similar in all samples. Though this study showed quantitative differences in the composition of the studied CLE and the response of bacterial cells to the composition of the growth media, and proved the potential of this additive for remediation of contaminated soil. It was shown that analysis of CLE and monitoring of the conversion of nitro aromatic compounds can be investigated by FT-IR spectroscopy as well as by conventional chemical methods.

  11. Immunomodulatory properties of probiotic bacteria

    DEFF Research Database (Denmark)

    Fink, Lisbeth Nielsen

    2007-01-01

    Certain lactic acid bacteria (LAB) are part of the commensal intestinal flora and considered beneficial for health, as they compete with pathogens for adhesion sites in the intestine and ferment otherwise indigestible compounds. Another important property of these so-called probiotic bacteria...... with bacteria, and the cytokine pattern induced by specific bacteria resembled the pattern induced in MoDC, except for TNF-alpha and IL-6, which were induced in response to different bacteria in blood DC/monocytes and monocyte-derived DC. Autologous NK cells produced IFN-gamma when cultured with blood DC......, monocytes and monocyte-derived DC and IL-12-inducing bacteria, whereas only DC induced IFN-gamma production in allogeneic T cells. In vitro-generated DC is a commonly used model of tissue DC, but they differ in certain aspects from intestinal DC, which are in direct contact with the intestinal microbiota...

  12. Cable Bacteria in Freshwater Sediments

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable...... bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures...... marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary...

  13. Contamination and potential biodegradation of polycyclic aromatic hydrocarbons in mangrove sediments of Xiamen, China.

    Science.gov (United States)

    Tian, Yun; Luo, Yuan-rong; Zheng, Tian-ling; Cai, Li-zhe; Cao, Xiao-xing; Yan, Chong-ling

    2008-06-01

    Five stations were established in the Fenglin mangrove area of Xiamen, China to determine the concentrations of polycyclic aromatic hydrocarbons (PAHs) and the numbers of PAH-degrading bacteria in surface sediments. Assessing the biodegradation potential of indigenous microorganisms and isolating the high molecule weight (HMW)-PAH degrading bacteria was also one of the aims of this work. The results showed that the total PAH concentration of sediments was 222.59 ng g(-1) dry weight, whereas the HMW-PAH benzo(a)pyrene (BaP) had the highest concentration among 16 individual PAH compounds. The variation in the numbers of PAH-degrading bacteria was 2.62 x 10(2)-5.67 x 10(4)CFU g(-1) dry weight. The addition of PAHs showed a great influence in increasing the microbial activity in mangrove sediments. A bacterial consortium, which could utilize BaP as the sole source of carbon and energy, and which was isolated from mangrove sediments and enriched in liquid medium for nearly one year degraded 32.8% of BaP after 63 days incubation.

  14. Products Distribution of Meta-Oriented Aromatic Polyamide Needs Improvement

    Institute of Scientific and Technical Information of China (English)

    Sun Maojian

    2007-01-01

    @@ Capacity holding the second place in the world Metaoriented aromatic polya-mide fiber was first developed by DuPont of the United States. Commercial production began in the late 1960s.Today the world's capacity to produce meta-oriented aromatic polyamide fiber is 28 150t/a, and DuPont holds a 78% market share.

  15. High atmosphere–ocean exchange of semivolatile aromatic hydrocarbons

    KAUST Repository

    González-Gaya, Belén

    2016-05-16

    Polycyclic aromatic hydrocarbons, and other semivolatile aromatic-like compounds, are an important and ubiquitous fraction of organic matter in the environment. The occurrence of semivolatile aromatic hydrocarbons is due to anthropogenic sources such as incomplete combustion of fossil fuels or oil spills, and other biogenic sources. However, their global transport, fate and relevance for the carbon cycle have been poorly assessed, especially in terms of fluxes. Here we report a global assessment of the occurrence and atmosphere-ocean fluxes of 64 polycyclic aromatic hydrocarbons analysed in paired atmospheric and seawater samples from the tropical and subtropical Atlantic, Pacific and Indian oceans. The global atmospheric input of polycyclic aromatic hydrocarbons to the global ocean is estimated at 0.09 Tg per month, four times greater than the input from the Deepwater Horizon spill. Moreover, the environmental concentrations of total semivolatile aromatic-like compounds were 10 2 -10 3 times higher than those of the targeted polycyclic aromatic hydrocarbons, with a relevant contribution of an aromatic unresolved complex mixture. These concentrations drive a large global deposition of carbon, estimated at 400 Tg C yr -1, around 15% of the oceanic CO2 uptake. © 2016 Macmillan Publishers Limited.

  16. Bis-perfluoroalkylation of aromatic compounds with sodium perfluoroalkanesulfinates

    Institute of Scientific and Technical Information of China (English)

    LIU, Jin-Tao(刘金涛); LU, He-Jun(吕贺军)

    2000-01-01

    Bis-perfluoroalkylation of aromatic compounds such as dimethoxybenzenes (2,4,6), anisole (8), pyridine (10) and quinoline (13) was accomplished by reaction with excess sodium perfluoroalkanesulfinates, RFSO2Na (1), in the presence of Mn(OAc)3·2H2O under mild conditions. The reaction provides a facile method for the synthesis of bis-perfluoroalkylated aromatic compounds.

  17. C-Nucleosides Derived from Simple Aromatic Hydrocarbons.

    Science.gov (United States)

    Chaudhuri, Narayan C; Ren, Rex X-F; Kool, Eric T

    1997-04-01

    We describe the synthesis, structure and DNA incorporation of a class of novel aromatic C-deoxynucleosides in which benzenes and larger polycyclic aromatics serve as DNA base analogs. Novel approaches have been developed for glycosidic bond formation and for epimenzation of the anomeric substitutents to β-configuration, and we describe some of the properties of such compounds in DNA.

  18. High atmosphere-ocean exchange of semivolatile aromatic hydrocarbons

    Science.gov (United States)

    González-Gaya, Belén; Fernández-Pinos, María-Carmen; Morales, Laura; Méjanelle, Laurence; Abad, Esteban; Piña, Benjamin; Duarte, Carlos M.; Jiménez, Begoña; Dachs, Jordi

    2016-06-01

    Polycyclic aromatic hydrocarbons, and other semivolatile aromatic-like compounds, are an important and ubiquitous fraction of organic matter in the environment. The occurrence of semivolatile aromatic hydrocarbons is due to anthropogenic sources such as incomplete combustion of fossil fuels or oil spills, and other biogenic sources. However, their global transport, fate and relevance for the carbon cycle have been poorly assessed, especially in terms of fluxes. Here we report a global assessment of the occurrence and atmosphere-ocean fluxes of 64 polycyclic aromatic hydrocarbons analysed in paired atmospheric and seawater samples from the tropical and subtropical Atlantic, Pacific and Indian oceans. The global atmospheric input of polycyclic aromatic hydrocarbons to the global ocean is estimated at 0.09 Tg per month, four times greater than the input from the Deepwater Horizon spill. Moreover, the environmental concentrations of total semivolatile aromatic-like compounds were 102-103 times higher than those of the targeted polycyclic aromatic hydrocarbons, with a relevant contribution of an aromatic unresolved complex mixture. These concentrations drive a large global deposition of carbon, estimated at 400 Tg C yr-1, around 15% of the oceanic CO2 uptake.

  19. Acoustofluidic bacteria separation

    Science.gov (United States)

    Li, Sixing; Ma, Fen; Bachman, Hunter; Cameron, Craig E.; Zeng, Xiangqun; Huang, Tony Jun

    2017-01-01

    Bacterial separation from human blood samples can help with the identification of pathogenic bacteria for sepsis diagnosis. In this work, we report an acoustofluidic device for label-free bacterial separation from human blood samples. In particular, we exploit the acoustic radiation force generated from a tilted-angle standing surface acoustic wave (taSSAW) field to separate Escherichia coli from human blood cells based on their size difference. Flow cytometry analysis of the E. coli separated from red blood cells shows a purity of more than 96%. Moreover, the label-free electrochemical detection of the separated E. coli displays reduced non-specific signals due to the removal of blood cells. Our acoustofluidic bacterial separation platform has advantages such as label-free separation, high biocompatibility, flexibility, low cost, miniaturization, automation, and ease of in-line integration. The platform can be incorporated with an on-chip sensor to realize a point-of-care sepsis diagnostic device.

  20. Bacteria, phages and septicemia.

    Directory of Open Access Journals (Sweden)

    Ausra Gaidelyte

    Full Text Available The use of phages is an attractive option to battle antibiotic resistant bacteria in certain bacterial infections, but the role of phage ecology in bacterial infections is obscure. Here we surveyed the phage ecology in septicemia, the most severe type of bacterial infection. We observed that the majority of the bacterial isolates from septicemia patients spontaneously secreted phages active against other isolates of the same bacterial strain, but not to the strain causing the disease. Such phages were also detected in the initial blood cultures, indicating that phages are circulating in the blood at the onset of sepsis. The fact that most of the septicemic bacterial isolates carry functional prophages suggests an active role of phages in bacterial infections. Apparently, prophages present in sepsis-causing bacterial clones play a role in clonal selection during bacterial invasion.

  1. Bacteriophages of methanotrophic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tyutikow, F.M. (All-Union Research Inst. for Genetics and Selection of Industrial Microorganisms, Moscow, USSR); Bespalova, I.A.; Rebentish, B.A.; Aleksandrushkina, N.N.; Krivisky, A.S.

    1980-10-01

    Bacteriophages of methanotrophic bacteria have been found in 16 out of 88 studied samples (underground waters, pond water, soil, gas and oil installation waters, fermentor cultural fluids, bacterial paste, and rumen of cattle) taken in different geographic zones of the Soviet Union. Altogether, 23 phage strains were isolated. By fine structure, the phages were divided into two types (with very short or long noncontractile tails); by host range and serological properties, they fell into three types. All phages had guanine- and cytosine-rich double-stranded deoxyribonucleic acid consisting of common nitrogen bases. By all of the above-mentioned properties, all phages within each of the groups were completely identical to one another, but differed from phages of other groups.

  2. Neutral Diboron Analogues of Archetypal Aromatic Species by Spontaneous Cycloaddition.

    Science.gov (United States)

    Arrowsmith, Merle; Böhnke, Julian; Braunschweig, Holger; Celik, Mehmet Ali; Claes, Christina; Ewing, William C; Krummenacher, Ivo; Lubitz, Katharina; Schneider, Christoph

    2016-09-05

    Among the numerous routes organic chemists have developed to synthesize benzene derivatives and heteroaromatic compounds, transition-metal-catalyzed cycloaddition reactions are the most elegant. In contrast, cycloaddition reactions of heavier alkene and alkyne analogues, though limited in scope, proceed uncatalyzed. In this work we present the first spontaneous cycloaddition reactions of lighter alkene and alkyne analogues. Selective addition of unactivated alkynes to boron-boron multiple bonds under ambient conditions yielded diborocarbon equivalents of simple aromatic hydrocarbons, including the first neutral 6 π-aromatic diborabenzene compound, a 2 π-aromatic triplet biradical 1,3-diborete, and a phosphine-stabilized 2 π-homoaromatic 1,3-dihydro-1,3-diborete. DFT calculations suggest that all three compounds are aromatic and show frontier molecular orbitals matching those of the related aromatic hydrocarbons, C6 H6 and C4 H4 (2+) , and homoaromatic C4 H5 (+) .

  3. (Hetero)aromatics from dienynes, enediynes and enyne-allenes.

    Science.gov (United States)

    Raviola, Carlotta; Protti, Stefano; Ravelli, Davide; Fagnoni, Maurizio

    2016-08-01

    The construction of aromatic rings has become a key objective for organic chemists. While several strategies have been developed for the functionalization of pre-formed aromatic rings, the direct construction of an aromatic core starting from polyunsaturated systems is yet a less explored field. The potential of such reactions in the formation of aromatics increased at a regular pace in the last few years. Nowadays, there are reliable and well-established procedures to prepare polyenic derivatives, such as dienynes, enediynes, enyne-allenes and hetero-analogues. This has stimulated their use in the development of innovative cycloaromatizations. Different examples have recently emerged, suggesting large potential of this strategy in the preparation of (hetero)aromatics. Accordingly, this review highlights the recent advancements in this field and describes the different conditions exploited to trigger the process, including thermal and photochemical activation, as well as the use of transition metal catalysis and the addition of electrophiles/nucleophiles or radical species.

  4. Microbial Degradation of Phenols and Aromatic Hydrocarbons in Creosote-contaminated Groundwater Under Nitrate-reducing Conditions

    DEFF Research Database (Denmark)

    Flyvbjerg, John; Arvin, Erik; Jensen, Bjørn K.;

    1993-01-01

    Batch experiments were carried out to investigate the biodegradation of phenols and aromatic hydrocarbons under anaerobic, nitrate-reducing conditions in groundwater from a creosote-contaminated site at Fredensborg, Denmark. The bacteria in the creosote-contaminated groundwater degraded a mixture...... of toluene, phenol, the cresols (o-, m- and p-cresol) and the dimethylphenols 2,4-DMP and 3,4-DMP at both 10° and 20°C. Benzene, the xylenes, napthalene, 2,3-DMP, 2,5-DMP, 2,6-DMP and 3,5-DMP were resistant to biodegradation during 7–12 months of incubation. It was demonstrated that the degradation...

  5. Novel Application of Cyclolipopeptide Amphisin: Feasibility Study as Additive to Remediate Polycyclic Aromatic Hydrocarbon (PAH Contaminated Sediments

    Directory of Open Access Journals (Sweden)

    Anne Groboillot

    2011-03-01

    Full Text Available To decontaminate dredged harbor sediments by bioremediation or electromigration processes, adding biosurfactants could enhance the bioavailability or mobility of contaminants in an aqueous phase. Pure amphisin from Pseudomonas fluorescens DSS73 displays increased effectiveness in releasing polycyclic aromatic hydrocarbons (PAHs strongly adsorbed to sediments when compared to a synthetic anionic surfactant. Amphisin production by the bacteria in the natural environment was also considered. DSS73’s growth is weakened by three model PAHs above saturation, but amphisin is still produced. Estuarine water feeding the dredged material disposal site of a Norman harbor (France allows both P. fluorescens DSS73 growth and amphisin production.

  6. Isolation of Asphaltene-Degrading Bacteria from Sludge Oil

    Directory of Open Access Journals (Sweden)

    Pingkan Aditiawati

    2015-03-01

    Full Text Available Sludge oil contains 30%–50% hydrocarbon fractions that comprise saturated fractions, aromatics, resins, and asphaltene. Asphaltene fraction is the most persistent fraction. In this research, the indigenous bacteria that can degrade asphaltene fractions from a sludge oil sample from Balikpapan that was isolated using BHMS medium (Bushnell-Hass Mineral Salt with 0.01% (w/v yeast extract, 2% (w/v asphaltene extract, and 2% (w/v sludge oil. The ability of the four isolates to degrade asphaltene fractions was conducted by the biodegradation asphaltene fractions test using liquid cultures in a BHMS medium with 0.01% (w/v yeast extract and 2% (w/v asphaltene extract as a carbon source. The parameters measured during the process of biodegradation of asphaltene fractions include the quantification of Total Petroleum Hydrocarbon (g, log total number of bacteria (CFU/ml, and pH. There are four bacteria (isolates 1, 2, 3, and 4 that have been characterized to degrade asphaltic fraction and have been identified as Bacillus sp. Lysinibacillus fusiformes, Acinetobacter sp., and Mycobacterium sp., respectively. The results showed that the highest ability to degrade asphaltene fractions is that of Bacillus sp. (isolate 1 and Lysinibacillus fusiformes (Isolate 2, with biodegradation percentages of asphaltene fractions being 50% and 55%, respectively, and growth rate at the exponential phase is 7.17x107 CFU/mL.days and 4.21x107 CFU/mL.days, respectively.

  7. Dual partitioning and attachment effects of rhamnolipid on pyrene biodegradation under bioavailability restrictions

    NARCIS (Netherlands)

    Congiu, E.; Parsons, J.R.; Ortega-Calvo, J.J.

    2015-01-01

    We investigated the effects of different bioavailability scenarios on the rhamnolipid-enhanced biodegradation of pyrene by the representative polycyclic aromatic hydrocarbon degrader Mycobacterium gilvum VM552. This biosurfactant enhanced biodegradation when pyrene was provided in the form of solid

  8. Pro-aromatic and anti-aromatic π-conjugated molecules: an irresistible wish to be diradicals

    KAUST Repository

    Zeng, Zebing

    2015-01-01

    © 2015 The Royal Society of Chemistry. Aromaticity is an important concept to understand the stability and physical properties of π-conjugated molecules. Recent studies on pro-aromatic and anti-aromatic molecules revealed their irresistible tendency to become diradicals in the ground state. Diradical character thus becomes another very important concept and it is fundamentally correlated to the physical (optical, electronic and magnetic) properties and chemical reactivity of most of the organic optoelectronic materials. Molecules with distinctive diradical character show unique properties which are very different from those of traditional closed-shell π-conjugated systems, and thus they have many potential applications in organic electronics, spintronics, non-linear optics and energy storage. This critical review first introduces the fundamental electronic structure of Kekulé diradicals within the concepts of anti-aromaticity and pro-aromaticity in the context of Hückel aromaticity and diradical character. Then recent research studies on various stable/persistent diradicaloids based on pro-aromatic and anti-aromatic compounds are summarized and discussed with regard to their synthetic chemistry, physical properties, structure-property relationships and potential material applications. A summary and personal perspective is given at the end.

  9. Synchronized aromaticity as an enthalpic driving force for the aromatic Cope rearrangement.

    Science.gov (United States)

    Babinski, David J; Bao, Xiaoguang; El Arba, Marie; Chen, Bo; Hrovat, David A; Borden, Weston Thatcher; Frantz, Doug E

    2012-10-03

    We report herein experimental and theoretical evidence for an aromatic Cope rearrangement. Along with several successful examples, our data include the first isolation and full characterization of the putative intermediate that is formed immediately after the initial [3,3] sigmatropic rearrangement. Calculations at the B3LYP/6-31G(d) level of theory predict reaction energy barriers in the range 22-23 kcal/mol for the [3,3]-rearrangement consistent with the exceptionally mild reaction conditions for these reactions. The experimental and computational results support a significant enthalpic contribution of the concomitant pyrazole ring formation that serves as both a kinetic and thermodynamic driving force for the aromatic Cope rearrangement.

  10. Polyenamines from aromatic diacetylenic diketones and diamines

    Science.gov (United States)

    Hergenrother, Paul M. (Inventor); Bass, Robert G. (Inventor); Sinsky, Mark S. (Inventor); Connell, John W. (Inventor)

    1987-01-01

    The synthesis and characterization of several polyenamine ketones are discussed wherein conjugated diacetylenic diketones and aromatic diamines are used as a route to the formation of high molecular weight polyenamine ketones which exhibit good mechanical properties and can be cast into creasible films. Typical polymerization conditions involved the reaction of stoichiometric amounts of 1,4- or 1,3-PPPO and a diamine at 60 to 130 C in m-cresol at (w/w) solids content of 8 to 26% for a specified period of time under a nitrogen atmosphere. Novel polyenamine ketones were prepared with inherent viscosities as high as 1.99 dl/g and tough, clear amber films with tensile strengths of 12,400 psi and tensile moduli of 397,000 psi were cast from solutions of the polymers in chloroform. In most cases, the elemental analyses for the polyenamine ketones agree within + or - 0.3% of the theoretical values.

  11. Structural Evolution of Interstellar Polycyclic Aromatic Hydrocarbons

    Science.gov (United States)

    Hammonds, Mark; Candian, Alessandra; Mori, Tamami; Usui, Fumihiko; Onaka, Takashi

    2015-08-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are an important reservoir for molecular carbon in the interstellar medium (ISM), and investigations into their chemistry and behaviour may be important to the understanding of how carbon is processed from simple forms into complex prebiotic molecules such as those detected in chondritic meteorites. In this study, infrared astronomical data from AKARI and other observatories are used together with laboratory and theoretical data to study variations in the structure of emitting PAHs in interstellar environments using spectroscopic decomposition techniques and bands arising from carbon-hydrogen bond vibrations at wavelengths from 3 - 14 microns. Results and inferences are discussed in terms of the processing of large carbonaceous molecules in astrophysical environments.

  12. The biodegradation vs. biotransformation of fluorosubstituted aromatics.

    Science.gov (United States)

    Kiel, Martina; Engesser, Karl-Heinrich

    2015-09-01

    Fluoroaromatics are widely and--in recent years--increasingly used as agrochemicals, starting materials for chemical syntheses and especially pharmaceuticals. This originates from the special properties the carbon-fluorine bond is imposing on organic molecules. Hence, fluoro-substituted compounds more and more are considered to be important potential environmental contaminants. On the other hand, the microbial potentials for their transformation and mineralization have received less attention in comparison to other haloaromatics. Due to the high electronegativity of the fluorine atom, its small size, and the extraordinary strength of the C-F bond, enzymes and mechanisms known to facilitate the degradation of chloro- or bromoarenes are not necessarily equally active with fluoroaromatics. Here, we review the literature on the microbial degradation of ring and side-chain fluorinated aromatic compounds under aerobic and anaerobic conditions, with particular emphasis being placed on the mechanisms of defluorination reactions.

  13. Photochemically induced oscillations of aromatic pentazadienes

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, T.; Hahn, C.; Wokaun, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Aromatic pentazadienes are used to enhance the laser induced ablation of standard polymers with low absorption in the UV. Therefore the photochemistry of substituted 1,5-diaryl-3-alkyl-1,4-pentazadiene monomers was studied with a pulsed excimer laser as irradiation source. The net photochemical reaction proceeds in an overall one-step pathway A{yields}B. Quantum yields for the laser decomposition were determined to be up to 10%. An oscillating behaviour of the absorption was found during the dark period following the irradiation. The temperature dependence of this dark reaction has been studied. An attempt to model this behaviour in terms of a non-linear coupling between heat released, heat transfer, and reaction kinetics will be described. (author) 4 figs., 4 refs.

  14. Environmental Remediation: Removal of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Nkansah, Marian Asantewah

    2012-11-15

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous persistent semi-volatile organic compounds. They are contaminants that are resistant to degradation and can remain in the environment for long periods due to their high degree of conjugation, and aromaticity. PAHs are present in industrial effluents as products of incomplete combustion processes of organic compounds. Petroleum, coal and shale oil contain extremely complex mixtures of these PAHs, and their transport and refining process can also result in the release of PAHs. It is therefore prudent that such effluents are treated before discharge into the environment. In this project, different approaches to the treatment of PAHs have been investigated. Hydrous pyrolysis has been explored as a potential technique for degrading PAHs in water using anthracene as a model compound. The experiments were performed under different conditions of temperature, substrate, redox systems and durations. The conditions include oxidising systems comprising pure water, hydrogen peroxide and Nafion-SiO2 solid catalyst in water; and reducing systems of formic acid and formic acid / Nafion-SiO2 / Pd-C catalysts to assess a range of reactivities. Products observed in GCMS analysis of the extract from the water phase include anthrone, anthraquinone, xanthone and multiple hydro-anthracene derivatives (Paper I). In addition a modified version of the Nafion-SiO2 solid catalyst in water oxidising system was tested; and reducing systems of formic acid and formic acid / Nafion-SiO2 / Pd-C catalysts were adopted for the conversion of a mixture of anthracene, fluorene and fluoranthene. The rate of conversion in the mixture was high as compared to that of only anthracene (Paper II). Also the use of LECA (Lightweight expanded clay aggregates) as an adsorbent (Paper III) for PAHs (phenanthrene, fluoranthene and pyrene) removal from water has been.(Author)

  15. Inhibitory effects of polycyclic aromatic hydrocarbons (PAHs) on photosynthetic performance are not related to their aromaticity.

    Science.gov (United States)

    Jajoo, Anjana; Mekala, Nageswara Rao; Tomar, Rupal Singh; Grieco, Michele; Tikkanen, Mikko; Aro, Eva-Mari

    2014-08-01

    Polycyclic aromatic hydrocarbons (PAHs) are very toxic and highly persistent environmental pollutants which accumulate in soil and affect growth of the plants adversely. This study aims to investigate inhibitory effects of 3 major PAH particularly on photosynthetic processes in Arabidopsis thaliana grown in soil treated with PAH. The 3 PAH chosen differ from each other in aromaticity (number of rings) comprising their structure (2 rings: naphthalene, 3 rings: anthracene and 4 rings: pyrene). Several growth parameters and Chlorophyll a fluorescence was monitored in PAH treated plants. BN-PAGe analysis was done in order to get information about change in the protein conformation. PAH treatment led to increased value of Fo which collaborated with increase in the amount of free LHC as seen through BN-Page analysis. Thus PAH were found to inhibit PS II photochemistry and caused distinct change in pigment composition. However the results led us to infer that 3-ring anthracence is more inhibitory as compared to 2-ring naphthalene and 4-ring pyrene. This indicates that aromaticity of PAH is unrelated to their response on photosynthetic processes.

  16. Exploring aromatic chemical space with NEAT: novel and electronically equivalent aromatic template.

    Science.gov (United States)

    Tu, Meihua; Rai, Brajesh K; Mathiowetz, Alan M; Didiuk, Mary; Pfefferkorn, Jeffrey A; Guzman-Perez, Angel; Benbow, John; Guimarães, Cristiano R W; Mente, Scot; Hayward, Matthew M; Liras, Spiros

    2012-05-25

    In this paper, we describe a lead transformation tool, NEAT (Novel and Electronically equivalent Aromatic Template), which can help identify novel aromatic rings that are estimated to have similar electrostatic potentials, dipoles, and hydrogen bonding capabilities to a query template; hence, they may offer similar bioactivity profiles. In this work, we built a comprehensive heteroaryl database, and precalculated high-level quantum mechanical (QM) properties, including electrostatic potential charges, hydrogen bonding ability, dipole moments, chemical reactivity, and othe properties. NEAT bioisosteric similarities are based on the electrostatic potential surface calculated by Brood, using the precalculated QM ESP charges and other QM properties. Compared with existing commercial lead transformation software, (1) NEAT is the only one that covers the comprehensive heteroaryl chemical space, and (2) NEAT offers a better characterization of novel aryl cores by using high-evel QM properties that are relevant to molecular interactions. NEAT provides unique value to medicinal chemists quickly exploring the largely uncharted aromatic chemical space, and one successful example of its application is discussed herein.

  17. Compost-mediated removal of polycyclic aromatic hydrocarbons from contaminated soil.

    Science.gov (United States)

    Sasek, V; Bhatt, M; Cajthaml, T; Malachová, K; Lednická, D

    2003-04-01

    Compost-assisted remediation of a manufactured-gas plant soil contaminated with polycyclic aromatic hydrocarbons (PAHs) was performed in thermally insulated composting chamber using mushroom compost consisting wheat straw, chicken manure, and gypsum. The degradation of individual PAHs was in range of 20-60% at the end of 54 days of composting followed by further increase of PAH removal (37-80%) after another 100 days of maturation. Both chemical analysis of the contaminated soil for PAHs and ecotoxicity tests on bioluminescent bacteria, earthworms, and plant seeds were performed before and after the composting. After the composting, inhibition of bioluminescence decreased, whereas no significant change in toxicity was observed for earthworm survival and seed germination. Using bacterial culture of Escherichia coli K12 genotoxicity tests were performed on samples taken from different parts of the composting pile; after the composting the decrease in genotoxicity was observed only in the sample taken from upper part of the composted pile.

  18. Isolation of microbe for asymmetric reduction of prochiral aromatic ketone and its reaction characters

    Institute of Scientific and Technical Information of China (English)

    YANG Zhonghua; ZENG Rong; WANG Yu; WANG Guanghui; YAO Shanjing

    2007-01-01

    The favorable microbes for the asymmetric reduction of prochiral aromatic ketones was isolated from soil using acetophenone as the sole carbon source,when the asymmetric reduction of acetophenone (ACP) to chiral α-phenethyl alcohol (PEA) was chosen as the model reaction.Two microbe strains with excellent catalytic activity were obtained.They were Geotrichum candidum and Pichia pastoris identified by bacteria identification.The product of the asymmetric reduction of ACP catalyzed by Pichia pastoris was mainly R-PEA and that by Geotrichum candidum was mainly S-PEA.The yield and enantiomeric excesses (e.e.) could respectively reach 75% and 90% for Pichiapastoris,and 80% and 70% for Geotrichum candidum,much higher than those catalyzed by baker's yeast.

  19. Polycyclic aromatic hydrocarbons (PAHs) enriching antibiotic resistance genes (ARGs) in the soils.

    Science.gov (United States)

    Chen, Baowei; He, Rong; Yuan, Ke; Chen, Enzhong; Lin, Lan; Chen, Xin; Sha, Sha; Zhong, Jianan; Lin, Li; Yang, Lihua; Yang, Ying; Wang, Xiaowei; Zou, Shichun; Luan, Tiangang

    2017-01-01

    The prevalence of antibiotic resistance genes (ARGs) in modern environment raises an emerging global health concern. In this study, soil samples were collected from three sites in petrochemical plant that represented different pollution levels of polycyclic aromatic hydrocarbons (PAHs). Metagenomic profiling of these soils demonstrated that ARGs in the PAHs-contaminated soils were approximately 15 times more abundant than those in the less-contaminated ones, with Proteobacterial being the preponderant phylum. Resistance profile of ARGs in the PAHs-polluted soils was characterized by the dominance of efflux pump-encoding ARGs associated with aromatic antibiotics (e.g., fluoroquinolones and acriflavine) that accounted for more than 70% of the total ARGs, which was significantly different from representative sources of ARG pollution due to wide use of antibiotics. Most of ARGs enriched in the PAHs-contaminated soils were not carried by plasmids, indicating the low possibilities of them being transferred between bacteria. Significant correlation was observed between the total abundance of ARGs and that of Proteobacteria in the soils. Proteobacteria selected by PAHs led to simultaneously enriching of ARGs carried by them in the soils. Our results suggested that PAHs could serve as one of selective stresses for greatly enriching of ARGs in the human-impacted environment.

  20. Ecophysiology of the anammox bacteria

    NARCIS (Netherlands)

    Kartal, Mustafa Boran

    2008-01-01

    Anaerobic ammonium oxidizing (anammox) bacteria oxidize ammonium to dinitrogen gas with nitrite as the electron acceptor. These bacteria are the key players in the global nitrogen cycle, responsible for the most of nitrogen production in natural ecosystems. The anammox process is also a cost-effecti

  1. Swimming bacteria in liquid crystal

    Science.gov (United States)

    Sokolov, Andrey; Zhou, Shuang; Aranson, Igor; Lavrentovich, Oleg

    2014-03-01

    Dynamics of swimming bacteria can be very complex due to the interaction between the bacteria and the fluid, especially when the suspending fluid is non-Newtonian. Placement of swimming bacteria in lyotropic liquid crystal produces a new class of active materials by combining features of two seemingly incompatible constituents: self-propelled live bacteria and ordered liquid crystals. Here we present fundamentally new phenomena caused by the coupling between direction of bacterial swimming, bacteria-triggered flows and director orientations. Locomotion of bacteria may locally reduce the degree of order in liquid crystal or even trigger nematic-isotropic phase transition. Microscopic flows generated by bacterial flagella disturb director orientation. Emerged birefringence patterns allow direct optical observation and quantitative characterization of flagella dynamics. At high concentration of bacteria we observed the emergence of self-organized periodic texture caused by bacteria swimming. Our work sheds new light on self-organization in hybrid bio-mechanical systems and can lead to valuable biomedical applications. Was supported by the US DOE, Office of Basic Energy Sciences, Division of Materials Science and Engineering, under the Contract No. DE AC02-06CH11357.

  2. The future role of aromatics in refining and petrochemistry. Proceedings of the DGMK-Conference (Authors' manuscripts)

    Energy Technology Data Exchange (ETDEWEB)

    Emig, G.; Rupp, M.; Weitkamp, J. [eds.

    1999-07-01

    Topic of this conference has been the furure role of aromatics in the refinign industry. The articles deal with the following topics: Refining; legal aspects in the aromatics market; transportation fuels; dearomatization; catalytic reforming and aromatics; separation processes for aromatics; oxidation and ammoxidation of aromatics; electrophilic substitution of aromatics; hydrogenation of benzene; zeolites. (orig./sr)

  3. Motility of electric cable bacteria

    DEFF Research Database (Denmark)

    Bjerg, Jesper Tataru; Damgaard, Lars Riis; Holm, Simon Agner

    2016-01-01

    Cable bacteria are filamentous bacteria that electrically couple sulfide oxidation and oxygen reduction at centimeter distances, and observations in sediment environments have suggested that they are motile. By time-lapse microscopy, we found that cable bacteria used gliding motility on surfaces...... with a highly variable speed of 0.50.3 ms1 (meanstandard deviation) and time between reversals of 155108 s. They frequently moved forward in loops, and formation of twisted loops revealed helical rotation of the filaments. Cable bacteria responded to chemical gradients in their environment, and around the oxic......-anoxic interface, they curled and piled up, with straight parts connecting back to the source of sulfide. Thus, it appears that motility serves the cable bacteria in establishing and keeping optimal connections between their distant electron donor and acceptors in a dynamic sediment environment....

  4. [Isolation and Identification of Petroleum Degradation Bacteria and Interspecific Interactions Among Four Bacillus Strains].

    Science.gov (United States)

    Wang, Jia-nan; Shi, Yan-yun; Zheng, Li-yan; Wang, Zhe; Cai, Zhang; Liu, Jie

    2015-06-01

    Six petroleum-degrading strains were isolated from oil-contaminated soil at Dagang oil field and oil sewage on Bohai offshore drilling platform in Tianjin using enrichment culture and isolation method. The physiological biochemical test together with 16S rDNA sequencing analysis indicated that they belonged to Bacillus (S1, S2, S3, S4), Pseudomonas (W1) and Ochrobactrum (W2), respectively. The strain S3 had the maximum degradation rate of alkane (41.3%) and aromatic hydrocarbon (30.9%) among all isolated strains showing the better degradation efficiency by endogenous bacteria when compared to that by the exogenous bacteria. The four Bacillus strains were used to construct microbiome, thereafter subjected to petroleum degradation efficiency test and analyzed. The results showed that microbiome F3 consisting of S1 and S4 had the maximum degradation rates of alkane (50.5%) and aromatic hydrocarbon (54.0%), which were 69.9% and 156.1% higher than those by single bacterium, respectively. Furthermore, they were 22.1% and 74.6% respectively higher than those by the most optimal degradation bacterium S3. Microbiome F4 consisting of S2 and S3 had the minimum degradation rates of alkane (18.5%) and aromatic hydrocarbon (18.9%) which were 55.3% and 39.0% lower than the degradation rates of single bacterium, respectively. The results also demonstrated that there were both microbial synergy promotion and antagonism inhibition among bacteria of the same genus in the petroleum degradation period. Bacteria with close affinity in Bacillus genus displayed mainly promoted petroleum degradation effect.

  5. Anaerobic degradation of benzene by marine sulfate-reducing bacteria

    Science.gov (United States)

    Musat, Florin; Wilkes, Heinz; Musat, Niculina; Kuypers, Marcel; Widdel, Friedrich

    2010-05-01

    Benzene, the archetypal aromatic hydrocarbon is a common constituent of crude oil and oil-refined products. As such, it can enter the biosphere through natural oil seeps or as a consequence of exploitation of fossil fuel reservoirs. Benzene is chemically very stable, due to the stabilizing aromatic electron system and to the lack of functional groups. Although the anaerobic degradation of benzene has been reported under denitrifying, sulfate-reducing and methanogenic conditions, the microorganisms involved and the initial biochemical steps of degradation remain insufficiently understood. Using marine sediment from a Mediterranean lagoon a sulfate-reducing enrichment culture with benzene as the sole organic substrate was obtained. Application of 16S rRNA gene-based methods showed that the enrichment was dominated (more than 85% of total cells) by a distinct phylotype affiliated with a clade of Deltaproteobacteria that include degraders of other aromatic hydrocarbons, such as naphthalene, ethylbenzene and m-xylene. Using benzoate as a soluble substrate in agar dilution series, several pure cultures closely related to Desulfotignum spp. and Desulfosarcina spp. were isolated. None of these strains was able to utilize benzene as a substrate and hybridizations with specific oligonucleotide probes showed that they accounted for as much as 6% of the total cells. Incubations with 13C-labeled benzene followed by Halogen in situ Hybridization - Secondary Ion Mass Spectroscopy (HISH-SIMS) analysis showed that cells of the dominant phylotype were highly enriched in 13C, while the accompanying bacteria had little or no 13C incorporation. These results demonstrate that the dominant phylotype was indeed the apparent benzene degrader. Dense-cell suspensions of the enrichment culture did not show metabolic activity toward added phenol or toluene, suggesting that benzene degradation did not proceed through anaerobic hydroxylation or methylation. Instead, benzoate was identified in

  6. Screening selectively harnessed environmental microbial communities for biodegradation of polycyclic aromatic hydrocarbons in moving bed biofilm reactors.

    Science.gov (United States)

    Demeter, Marc A; Lemire, Joseph A; Mercer, Sean M; Turner, Raymond J

    2017-03-01

    Bacteria are often found tolerating polluted environments. Such bacteria may be exploited to bioremediate contaminants in controlled ex situ reactor systems. One potential strategic goal of such systems is to harness microbes directly from the environment such that they exhibit the capacity to markedly degrade organic pollutants of interest. Here, the use of biofilm cultivation techniques to inoculate and activate moving bed biofilm reactor (MBBR) systems for the degradation of polycyclic aromatic hydrocarbons (PAHs) was explored. Biofilms were cultivated from 4 different hydrocarbon contaminated sites using a minimal medium spiked with the 16 EPA identified PAHs. Overall, all 4 inoculant sources resulted in biofilm communities capable of tolerating the presence of PAHs, but only 2 of these exhibited enhanced PAH catabolic gene prevalence coupled with significant degradation of select PAH compounds. Comparisons between inoculant sources highlighted the dependence of this method on appropriate inoculant screening and biostimulation efforts.

  7. Structure-Activity Relationships in Nitro-Aromatic Compounds

    Science.gov (United States)

    Vogt, R. A.; Rahman, S.; Crespo-Hernández, C. E.

    Many nitro-aromatic compounds show mutagenic and carcinogenic properties, posing a potential human health risk. Despite this potential health hazard, nitro-aromatic compounds continue to be emitted into ambient air from municipal incinerators, motor vehicles, and industrial power plants. As a result, understanding the structural and electronic factors that influence mutagenicity in nitro-aromatic compounds has been a long standing objective. Progress toward this goal has accelerated over the years, in large part due to the synergistic efforts among toxicology, computational chemistry, and statistical modeling of toxicological data. The concerted influence of several structural and electronic factors in nitro-aromatic compounds makes the development of structure-activity relationships (SARs) a paramount challenge. Mathematical models that include a regression analysis show promise in predicting the mutagenic activity of nitro-aromatic compounds as well as in prioritizing compounds for which experimental data should be pursued. A major challenge of the structure-activity models developed thus far is their failure to apply beyond a subset of nitro-aromatic compounds. Most quantitative structure-activity relationship papers point to statistics as the most important confirmation of the validity of a model. However, the experimental evidence shows the importance of the chemical knowledge in the process of generating models with reasonable applicability. This chapter will concisely summarize the structural and electronic factors that influence the mutagenicity in nitro-aromatic compounds and the recent efforts to use quantitative structure-activity relationships to predict those physicochemical properties.

  8. Pi-Pi STACKING OF THE AROMATIC GROUPS IN LIGNOSULFONATES

    Directory of Open Access Journals (Sweden)

    Yonghong Deng,

    2012-01-01

    Full Text Available Sodium lignosulfonate (SL fractions with narrow molecular weight distribution and known salt content were used to investigate – stacking of the aromatic groups in SL. Results show that the charge-free aromatic groups of SL tend to form oriented – stacking with the spectroscopic characteristics of J–aggregates. The formation of J–aggregates in SL are recognized by a significant spectral red shift in fluorescent excitation spectra. The other effects that may cause spectral shift, such as the SL species, solvent effect, and the impurities, are investigated to confirm that the formation of J-aggregates is the only viable explanation for the significant spectral redshift of SL. Salt causes molecular shrinkage of SL polyelectrolytes, but has no influence on J–aggregates of the aromatic groups as detected by lack of spectral shift, indicating that the aromatic groups are charge-free. This suggests that not all the aromatic groups but only the charge-free aromatic groups can form – stacking. This work demonstrates the presence of J–aggregation in aqueous SL solutions for the first time, which gives an insight in understanding the preferred orientation of the aromatic groups in lignin-based biopolymers.

  9. How non-conventional feedstocks will affect aromatics technologies

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, E. [Clariant Produkte (Deutschland) GmbH, Muenchen (Germany)

    2013-11-01

    The abundance of non-conventional feedstocks such as coal and shale gas has begun to affect the availability of traditional base chemicals such as propylene and BTX aromatics. Although this trend is primarily fueled by the fast growing shale gas economy in the US and the abundance of coal in China, it will cause the global supply and demand situation to equilibrate across the regions. Lower demand for gasoline and consequently less aromatics rich reformate from refineries will further tighten the aromatics markets that are expected to grow at healthy rates, however. Refiners can benefit from this trend by abandoning their traditional fuel-oriented business model and becoming producers of petrochemical intermediates, with special focus on paraxylene (PX). Cheap gas from coal (via gasification) or shale reserves is an advantaged feedstock that offers a great platform to make aromatics in a cost-competitive manner, especially in regions where naphtha is in short supply. Gas condensates (LPG and naphtha) are good feedstocks for paraffin aromatization, and methanol from coal or (shale) gas can be directly converted to BTX aromatics (MTA) or alkylated with benzene or toluene to make paraxylene. Most of today's technologies for the production and upgrading of BTX aromatics and their derivatives make use of the unique properties of zeolites. (orig.)

  10. Epoxy Coenzyme A Thioester pathways for degradation of aromatic compounds.

    Science.gov (United States)

    Ismail, Wael; Gescher, Johannes

    2012-08-01

    Aromatic compounds (biogenic and anthropogenic) are abundant in the biosphere. Some of them are well-known environmental pollutants. Although the aromatic nucleus is relatively recalcitrant, microorganisms have developed various catabolic routes that enable complete biodegradation of aromatic compounds. The adopted degradation pathways depend on the availability of oxygen. Under oxic conditions, microorganisms utilize oxygen as a cosubstrate to activate and cleave the aromatic ring. In contrast, under anoxic conditions, the aromatic compounds are transformed to coenzyme A (CoA) thioesters followed by energy-consuming reduction of the ring. Eventually, the dearomatized ring is opened via a hydrolytic mechanism. Recently, novel catabolic pathways for the aerobic degradation of aromatic compounds were elucidated that differ significantly from the established catabolic routes. The new pathways were investigated in detail for the aerobic bacterial degradation of benzoate and phenylacetate. In both cases, the pathway is initiated by transforming the substrate to a CoA thioester and all the intermediates are bound by CoA. The subsequent reactions involve epoxidation of the aromatic ring followed by hydrolytic ring cleavage. Here we discuss the novel pathways, with a particular focus on their unique features and occurrence as well as ecological significance.

  11. Investigation of isotopic and biomolecular approaches as new bio-indicators for long term natural attenuation of monoaromatic compounds in deep terrestrial aquifers by gram-positive sporulated sulfate-reducing bacteria of the genus Desulfotomaculum.

    Directory of Open Access Journals (Sweden)

    Thomas eAüllo

    2016-02-01

    Full Text Available Deep subsurface aquifers despite difficult access, represent important water resources and, at the same time, are key locations for subsurface engineering activities for the oil and gas industries, geothermal energy and CO2 or energy storage. Formation water originating from a 760 meter-deep geological gas storage aquifer was sampled and microcosms were set up to test the biodegradation potential of BTEX by indigenous microorganisms. After a long incubation period, with several subcultures, a sulfate-reducing consortium composed of only two Desulfotomaculum populations was observed able to degrade benzene, toluene and ethylbenzene, extending the number of hydrocarbonoclastic–related species among the Desulfotomaculum genus. Furthermore, we were able to couple specific carbon and hydrogen isotopic fractionation during benzene removal and the results obtained by dual compound specific isotope analysis (εC = -2.4 ‰ ± 0.3 ‰; εH = -57 ‰ ± 0.98 ‰; AKIEC: 1.0146 ± 0.0009 and AKIEH: 1.5184 ± 0.0283 were close to those obtained previously in sulfate-reducing conditions: this finding could confirm the existence of a common enzymatic reaction involving sulfate-reducers to activate benzene anaerobically. Although we cannot assign the role of each population of Desulfotomaculum in the mono-aromatic hydrocarbon degradation, this study suggests an important role of the genus Desulfotomaculum as potential biodegrader among indigenous populations in subsurface habitats. This community represents the simplest model of benzene-degrading anaerobes originating from the deepest subterranean settings ever described. As Desulfotomaculum species are often encountered in subsurface environments, this study provides some interesting results for assessing the natural response of these specific hydrologic systems in response to BTEX contamination during remediation projects.

  12. Theoretical study of aromaticity in inorganic tetramer clusters

    Indian Academy of Sciences (India)

    Sandeep Nigam; Chiranjib Majumder; S K Kulshreshtha

    2006-11-01

    Ground state geometry and electronic structure of M$^{2-}_{4}$ cluster (M = B, Al, Ga) have been investigated to evaluate their aromatic properties. The calculations are performed by employing the Density Functional Theory (DFT) method. It is found that all these three clusters adopt square planar configuration. Results reveal that square planar M$^{2-}_{4}$ dianion exhibits characteristics of multifold aromaticity with two delocalised -electrons. In spite of the unstable nature of these dianionic clusters in the gas phase, their interaction with the sodium atoms forms very stable dipyramidal M4Na2 complexes while maintaining their square planar structure and aromaticity.

  13. Aromatic oligoamides with a rare ortho-connectivity

    DEFF Research Database (Denmark)

    Hjelmgaard, T.; Nielsen, John

    2013-01-01

    Even though aromatic oligoamides composed of aromatic amino acids in a "one-way sequence" attract ever increasing research interest, backbones connected through ortho-linked aromatics remain rare. Herein, we present the first synthesis and study of N-alkylated ortho-aminomethyl- benzamides termed...... studies indicated a more restricted rotation about the amide bonds in ortho-arylopeptoids, presumably due to a more congested backbone structure resulting from the ortho-connectivity pattern. Intriguingly, tert-butyl and phenyl side chains offer complete control over the amide conformations; whereas...

  14. Plant-bacteria partnership: phytoremediation of hydrocarbons contaminated soil and expression of catabolic genes

    Directory of Open Access Journals (Sweden)

    Hamna Saleem

    2016-01-01

    Full Text Available Petroleum hydrocarbons are harmful to living organisms when they are exposed in natural environment. Once they come in contact, it is not an easy to remove them because many of their constituents are persistent in nature. To achieve this target, different approaches have been exploited by using plants, bacteria, and plant-bacteria together. Among them, combined use of plants and bacteria has gained tremendous attention as bacteria possess set of catabolic genes which produce catabolic enzymes to decontaminate hydrocarbons. In return, plant ooze out root exudates containing nutrients and necessary metabolites which facilitate the microbial colonization in plant rhizosphere. This results into high gene abundance and gene expression in the rhizosphere and, thus, leads to enhanced degradation. Moreover, high proportions of beneficial bacteria helps plant to gain more biomass due to their plant growth promoting activities and production of phytohromones. This review focuses functioning and mechanisms of catabolic genes responsible for degradation of straight chain and aromatic hydrocarbons with their potential of degradation in bioremediation. With the understanding of expression mechanisms, rate of degradation can be enhanced by adjusting environmental factors and acclimatizing plant associated bacteria in plant rhizosphere.

  15. Motility of Electric Cable Bacteria

    OpenAIRE

    Bjerg, Jesper Tataru; Damgaard, Lars Riis; Holm, Simon Agner; Schramm, Andreas; Nielsen, Lars Peter

    2016-01-01

    Cable bacteria are filamentous bacteria that electrically couple sulfide oxidation and oxygen reduction at centimeter distances, and observations in sediment environments have suggested that they are motile. By time-lapse microscopy, we found that cable bacteria used gliding motility on surfaces with a highly variable speed of 0.5 ± 0.3 μm s−1 (mean ± standard deviation) and time between reversals of 155 ± 108 s. They frequently moved forward in loops, and formation of twisted loops revealed ...

  16. Sampling bacteria with a laser

    Science.gov (United States)

    Schwarzwälder, Kordula; Rutschmann, Peter

    2014-05-01

    Water quality is a topic of high interest and it's getting more and more important due to climate change and the implementation of European Water Framework Directive (WFD). One point of interest here is the inflow of bacteria into a river caused by combined sewer overflows which lead untreated wastewater including bacteria directly into a river. These bacteria remain in the river for a certain time, they settle down and can be remobilised again. In our study we want to investigate these processes of sedimentation and resuspension and use the results for the development of a software module coupled with the software Flow3D. Thereby we should be able to simulate and therefore predict the water quality influenced by combined sewer overflows. Hence we need to get information about the bacteria transport and fate. We need to know about the size of the bacteria or of the bacteria clumps and the size of the particles the bacteria are attached to. The agglomerates lead to different characteristics and velocities of settlement. The timespan during this bacteria can be detected in the bulk phase depends on many factors like the intensity of UV light, turbidity of the water, the temperature of the water, if there are grazers and a lot more. The size, density and composition of the agglomerates is just a part of all these influencing factors, but it is extremely difficult to differ between the other effects if we have no information about the simple sedimentation in default of these basic information. However we have a big problem getting the data. The chaining between bacteria or bacteria and particles is not too strong, so filtering the water to get a sieving curve may destroy these connections. We did some experiments similar to PIV (particle image velocimetry) measurements and evaluated the pictures with a macro written for the software ImageJ. Doing so we were able to get the concentration of bacteria in the water and collect information about the size of the bacteria. We

  17. Complications with remediation strategies involving the biodegradation and detoxification of recalcitrant contaminant aromatic hydrocarbons.

    Science.gov (United States)

    Frenzel, Max; Scarlett, Alan; Rowland, Steven J; Galloway, Tamara S; Burton, Sara K; Lappin-Scott, Hilary M; Booth, Andy M

    2010-09-01

    Environmentally persistent aromatic hydrocarbons known as unresolved complex mixtures (UCMs) derived from crude oil can be accumulated by, and elicit toxicological responses in, marine organisms (e.g. mussels, Mytilus edulis). Comprehensive two-dimensional gas chromatography time-of-flight mass-spectrometry (GCxGC-ToF-MS) previously revealed that these UCMs included highly branched alkylated aromatic hydrocarbons. Here, the effects of biodegradation on the toxicity and chemical composition of an aromatic UCM hydrocarbon fraction isolated from Tia Juana Pesado (TJP) crude oil were examined. 48h exposure of mussels to the aromatic hydrocarbon fraction (F2) resulted in tissue concentrations of 900microgg(-1) (dry wt.) and approximately 45% decrease in clearance rate. Over 90% of the hydrocarbon burden corresponded to an UCM. Following a 5day recovery period, GCxGC-ToF-MS analysis of the tissues indicated depuration of most accumulated hydrocarbons and clearance rates returned to those observed in controls. To assess the potential of biodegradation to reduce UCM toxicity, TJP F2 was exposed to bacteria isolated from Whitley Bay, UK, for 46days. Mussels exposed to the undegraded TJP F2 from the abiotic control exhibited a reduction in clearance rate comparable with values for the pure crude oil TJP F2. Clearance rates of mussels exposed to biodegraded TJP F2 were statistically similar to seawater controls, suggesting biodegradation had reduced the TJP F2 toxicity. GCxGC-ToF-MS analysis revealed the same compound groups in the tissue of mussels exposed to pure TJP F2, undegraded TJP F2 and biodegraded TJP F2 samples; however >300 fewer compounds were observed in the biodegraded (954 compounds) compared to the undegraded TJP F2 (1261). The compound distributions were markedly different, possibly accounting for the decrease in toxicity. Extraction and analysis of pelleted bacterial cell material revealed that a significant proportion of the TJP F2 had adsorbed onto the

  18. Beer spoilage bacteria and hop resistance

    NARCIS (Netherlands)

    Sakamoto, K; Konings, WN

    2003-01-01

    For brewing industry, beer spoilage bacteria have been problematic for centuries. They include some lactic acid bacteria such as Lactobacillus brevis, Lactobacillus lindneri and Pediococcus damnosus, and some Gram-negative bacteria such as Pectinatus cerevisiiphilus, Pectinatus frisingensis and Mega

  19. Six-Membered Aromatic Polyazides: Synthesis and Application

    Directory of Open Access Journals (Sweden)

    Sergei V. Chapyshev

    2015-10-01

    Full Text Available Aromatic polyazides are widely used as starting materials in organic synthesis and photochemical studies, as well as photoresists in microelectronics and as cross-linking agents in polymer chemistry. Some aromatic polyazides possess high antitumor activity, while many others are of considerable interest as high-energy materials and precursors of high-spin nitrenes and C3N4 carbon nitride nanomaterials. The use of aromatic polyazides in click-reactions may be a new promising direction in the design of various supramolecular systems possessing interesting chemical, physical and biological properties. This review is devoted to the synthesis, properties and applications of six-membered aromatic compounds containing three and more azido groups in the ring.

  20. Biodegradation Rates of Aromatic Contaminants in Biofilm Reactors

    DEFF Research Database (Denmark)

    Arcangeli, Jean-Pierre; Arvin, Erik

    1995-01-01

    This study has shown that microorganisms can adapt to degrade mixtures of aromatic pollutants at relatively high rates in the μg/l concentration range. The biodegradation rates of the following compounds were investigated in biofilm systems: aromatic hydrocarbons, phenol, methylphenols, chlorophe......This study has shown that microorganisms can adapt to degrade mixtures of aromatic pollutants at relatively high rates in the μg/l concentration range. The biodegradation rates of the following compounds were investigated in biofilm systems: aromatic hydrocarbons, phenol, methylphenols......-reducing conditions, toluene was easily biodegraded. The xylenes and ethylbenzene were degraded cometabolically if toluene was used as a primary carbon source; their removal was influenced by competitive inhibition with toluene. These interaction phenomena are discussed in this paper and a kinetic model taking...

  1. Six-Membered Aromatic Polyazides: Synthesis and Application.

    Science.gov (United States)

    Chapyshev, Sergei V

    2015-10-21

    Aromatic polyazides are widely used as starting materials in organic synthesis and photochemical studies, as well as photoresists in microelectronics and as cross-linking agents in polymer chemistry. Some aromatic polyazides possess high antitumor activity, while many others are of considerable interest as high-energy materials and precursors of high-spin nitrenes and C₃N₄ carbon nitride nanomaterials. The use of aromatic polyazides in click-reactions may be a new promising direction in the design of various supramolecular systems possessing interesting chemical, physical and biological properties. This review is devoted to the synthesis, properties and applications of six-membered aromatic compounds containing three and more azido groups in the ring.

  2. Assessing Uncertainty of Interspecies Correlation Estimation Models for Aromatic Compounds

    Science.gov (United States)

    We developed Interspecies Correlation Estimation (ICE) models for aromatic compounds containing 1 to 4 benzene rings to assess uncertainty in toxicity extrapolation in two data compilation approaches. ICE models are mathematical relationships between surrogate and predicted test ...

  3. Aromatic Plants as a Source of Bioactive Compounds

    Directory of Open Access Journals (Sweden)

    Panagiota Florou-Paneri

    2012-09-01

    Full Text Available Aromatic plants, also known as herbs and spices, have been used since antiquity as folk medicine and as preservatives in foods. The best known aromatic plants, such as oregano, rosemary, sage, anise, basil, etc., originate from the Mediterranean area. They contain many biologically active compounds, mainly polyphenolics, which have been found to possess antimicrobial, antioxidant, antiparasitic, antiprotozoal, antifungal, and anti-inflammatory properties. Currently, the demand for these plants and their derivatives has increased because they are natural, eco-friendly and generally recognized as safe products. Therefore, aromatic plants and their extracts have the potential to become new generation substances for human and animal nutrition and health. The purpose of this review is to provide an overview of the literature surrounding the in vivo and in vitro use of aromatic plants.

  4. Application of aromatization catalyst in synthesis of carbon nanotubes

    Indian Academy of Sciences (India)

    Song Rongjun; Yang Yunpeng; Ji Qing; Li Bin

    2012-02-01

    In a typical chemical vapour deposition (CVD) process for synthesizing carbon nanotubes (CNTs), it was found that the aromatization catalysts could promote effectively the formation of CNT. The essence of this phenomenon was attributed to the fact that the aromatization catalyst can accelerate the dehydrogenation–cyclization and condensation reaction of carbon source, which belongs to a necessary step in the formation of CNTs. In this work, aromatization catalysts, H-beta zeolite, HZSM-5 zeolite and organically modified montmorillonite (OMMT) were chosen to investigate their effects on the formation of multi-walled carbon nanotubes (MWCNTs) via pyrolysis method when polypropylene and 1-hexene as carbon source and Ni2O3 as the charring catalyst. The results demonstrated that the combination of those aromatization catalysts with nickel catalyst can effectively improve the formation of MWCNTs.

  5. Affinity labelling enzymes with esters of aromatic sulfonic acids

    Science.gov (United States)

    Wong, Show-Chu; Shaw, Elliott

    1977-01-01

    Novel esters of aromatic sulfonic acids are disclosed. The specific esters are nitrophenyl p- and m-amidinophenylmethanesulfonate. Also disclosed is a method for specific inactivation of the enzyme, thrombin, employing nitrophenyl p-amidinophenylmethanesulfonate.

  6. Biodegradation of aliphatic and aromatic polycarbonates.

    Science.gov (United States)

    Artham, Trishul; Doble, Mukesh

    2008-01-01

    Polycarbonate is one of the most widely used engineering plastics because of its superior physical, chemical, and mechanical properties. Understanding the biodegradation of this polymer is of great importance to answer the increasing problems in waste management of this polymer. Aliphatic polycarbonates are known to biodegrade either through the action of pure enzymes or by bacterial whole cells. Very little information is available that deals with the biodegradation of aromatic polycarbonates. Biodegradation is governed by different factors that include polymer characteristics, type of organism, and nature of pretreatment. The polymer characteristics such as its mobility, tacticity, crystallinity, molecular weight, the type of functional groups and substituents present in its structure, and plasticizers or additives added to the polymer all play an important role in its degradation. The carbonate bond in aliphatic polycarbonates is facile and hence this polymer is easily biodegradable. On the other hand, bisphenol A polycarbonate contains benzene rings and quaternary carbon atoms which form bulky and stiff chains that enhance rigidity. Even though this polycarbonate is amorphous in nature because of considerable free volume, it is non-biodegradable since the carbonate bond is inaccessible to enzymes because of the presence of bulky phenyl groups on either side. In order to facilitate the biodegradation of polymers few pretreatment techniques which include photo-oxidation, gamma-irradiation, or use of chemicals have been tested. Addition of biosurfactants to improve the interaction between the polymer and the microorganisms, and blending with natural or synthetic polymers that degrade easily, can also enhance the biodegradation.

  7. Porphyrins Fused with Unactivated Polycyclic Aromatic Hydrocarbons

    KAUST Repository

    Diev, Vyacheslav V.

    2012-01-06

    A systematic study of the preparation of porphyrins with extended conjugation by meso,β-fusion with polycyclic aromatic hydrocarbons (PAHs) is reported. The meso-positions of 5,15-unsubstituted porphyrins were readily functionalized with PAHs. Ring fusion using standard Scholl reaction conditions (FeCl 3, dichloromethane) occurs for perylene-substituted porphyrins to give a porphyrin β,meso annulated with perylene rings (0.7:1 ratio of syn and anti isomers). The naphthalene, pyrene, and coronene derivatives do not react under Scholl conditions but are fused using thermal cyclodehydrogenation at high temperatures, giving mixtures of syn and anti isomers of the meso,β-fused porphyrins. For pyrenyl-substituted porphyrins, a thermal method gives synthetically acceptable yields (>30%). Absorption spectra of the fused porphyrins undergo a progressive bathochromic shift in a series of naphthyl (λ max = 730 nm), coronenyl (λ max = 780 nm), pyrenyl (λ max = 815 nm), and perylenyl (λ max = 900 nm) annulated porphyrins. Despite being conjugated with unsubstituted fused PAHs, the β,meso-fused porphyrins are more soluble and processable than the parent nonfused precursors. Pyrenyl-fused porphyrins exhibit strong fluorescence in the near-infrared (NIR) spectral region, with a progressive improvement in luminescent efficiency (up to 13% with λ max = 829 nm) with increasing degree of fusion. Fused pyrenyl-porphyrins have been used as broadband absorption donor materials in photovoltaic cells, leading to devices that show comparatively high photovoltaic efficiencies. © 2011 American Chemical Society.

  8. Synthesis and characterization of organosoluble aromatic copolyimids

    Institute of Scientific and Technical Information of China (English)

    YANG Jintian; HUANG Wei; ZHOU Yongfeng; YAN Deyue

    2007-01-01

    A series of aromatic copolyimides was success fully synthesized from the commercial pyromellitic dianhy dride (PMDA) with a commercial diamine p-phenyldiamine (PDA) and a diamine 4,4'-methylenebis-(2-tert-butylaniline)(MBTBA) specially designed by the authors.The copoly imides were characterized by Infra-red (IR),Nuclear Magnetic Resonance (NMR),Gel Permeation Chromato graphy (GPC),Ultraviolet Visual (UV-Vis),Thermogra vimetic Analysis (TGA) and Dynamic Mechanical Analysis (DMA).The copolyimide was precipitated in m-cresol in the polymerization process when the molar ratio of MBTBA and PDA was lower than 6/4.The number-average molecular weight of the soluble copolyimides measured by GPC was larger than 4.0 x 104,and the polydispersity index was higher than 1.5.Only one glass transition temperature of these copolyimdies was detected around 360℃ by DMA.The copolyimides did not show appreciable decomposition up to 500℃ under N2,and the thermal stability of the copolyimide increased a little with the introduction of PDA into the polyimide main chain.

  9. Highly Energetic, Low Sensitivity Aromatic Peroxy Acids.

    Science.gov (United States)

    Gamage, Nipuni-Dhanesha H; Stiasny, Benedikt; Stierstorfer, Jörg; Martin, Philip D; Klapötke, Thomas M; Winter, Charles H

    2016-02-18

    The synthesis, structure, and energetic materials properties of a series of aromatic peroxy acid compounds are described. Benzene-1,3,5-tris(carboperoxoic) acid is a highly sensitive primary energetic material, with impact and friction sensitivities similar to those of triacetone triperoxide. By contrast, benzene-1,4-bis(carboperoxoic) acid, 4-nitrobenzoperoxoic acid, and 3,5-dinitrobenzoperoxoic acid are much less sensitive, with impact and friction sensitivities close to those of the secondary energetic material 2,4,6-trinitrotoluene. Additionally, the calculated detonation velocities of 3,5-dinitrobenzoperoxoic acid and 2,4,6-trinitrobenzoperoxoic acid exceed that of 2,4,6-trinitrotoluene. The solid-state structure of 3,5-dinitrobenzoperoxoic acid contains intermolecular O-H⋅⋅⋅O hydrogen bonds and numerous N⋅⋅⋅O, C⋅⋅⋅O, and O⋅⋅⋅O close contacts. These attractive lattice interactions may account for the less sensitive nature of 3,5-dinitrobenzoperoxoic acid.

  10. Atmospheric polycyclic aromatic hydrocarbons in Seoul, Korea

    Science.gov (United States)

    Park, Seung S.; Kim, Young J.; Kang, Chang H.

    Daily particulate- and vapor-phase polycyclic aromatic hydrocarbons (PAH) samples were collected at an urban site in Seoul, Korea, during five intensive sampling campaigns between October 1998 and December 1999. PAH samples collected on quartz fiber filters and PUF plugs were first extracted using dichloromethane with ultrasonication and supercritical fluid extraction methods, respectively, and then analyzed by GC/MSD/SIM. Seasonal trends in atmospheric PAH concentrations in the study area were highly influenced by fossil fuel usage for domestic heating, boundary layer height, and air temperature. The relative benzo[a]pyrene amount and particulate organic to elemental carbon ratio calculated from the measurement results suggested that photo-oxidation is not an important factor in the variation of PAH concentrations during the summer sampling periods. Correlation studies between specific PAH of the individual factors identified by principal component factor analysis and meteorological parameters revealed that both temperature and relative humidity gave greater effects on the semi-volatile PAH, PHEN and FLT, rather than on the heavier PAH, B(b+k)F and BghiP.

  11. Structure and Aromaticity of AlCO-substituted Semibullvalene

    Institute of Scientific and Technical Information of China (English)

    YAO Wen-Zhi; WU Hai-Shun

    2007-01-01

    The structures, energies and aromaticity (the nuclear-independent chemical shifts,NICS) of AlCO-substituted semibullvalenes were investigated at the B3LYP/6-311+G** level.Similar to BCO-substituted analogues, [2,6]-AlCO-semibullvalene is neutral bishomoaromatic.The NICS values reveal that the aromaticity of AlCO-substituted structures is smaller than that of BCO analogues.

  12. Engineered biosynthesis of bacterial aromatic polyketides in Escherichia coli

    OpenAIRE

    Zhang, Wenjun; Li, Yanran; Tang, Yi

    2008-01-01

    Bacterial aromatic polyketides are important therapeutic compounds including front line antibiotics and anticancer drugs. It is one of the last remaining major classes of natural products of which the biosynthesis has not been reconstituted in the genetically superior host Escherichia coli. Here, we demonstrate the engineered biosynthesis of bacterial aromatic polyketides in E. coli by using a dissected and reassembled fungal polyketide synthase (PKS). The minimal PKS of the megasynthase PKS4...

  13. Environmental Remediation: Removal of polycyclic aromatic hydrocarbons Dissertation

    OpenAIRE

    Nkansah, Marian Asantewah

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous persistent semi-volatile organic compounds. They are contaminants that are resistant to degradation and can remain in the environment for long periods due to their high degree of conjugation, and aromaticity. PAHs are present in industrial effluents as products of incomplete combustion processes of organic compounds. Petroleum, coal and shale oil contain extremely complex mixtures of these PAHs, and their transport and refi...

  14. Transient Crystallization of an Aromatic Polyetherimide: Effect of Annealing

    Science.gov (United States)

    1991-01-01

    on the annealing behavior of an aromatic polyetherimide ( Ultem 5001). Although crystallization from the melt did not occur, crystallinity was easily...in LARC-TPI. 10-’ 3 Ultem aromatic polyetherimide, first reported by Serfaty, 15 is an amorphous thermoplastic with the following structure for a...commercially available Ultem 1000. 0 0 0n Our studies have been carried out on Ultem 5001-based materials which is a new aro- matic polyetherimide with

  15. KINETICS OF MESOPHASE FORMATION OF A LYOTROPIC AROMATIC POLYAMIDE

    Institute of Scientific and Technical Information of China (English)

    CHEN Shouxi

    1989-01-01

    The kinetics of mesophase formation of a lyotropic aromatic polyamide from isotropic state has been studied by means of depolarized light intensity. Avrami type analysis of the data gives an exponent close to 1, which suggests the nucleation followed by one-dimensional growth. No influence of blending flexible chain from nylon 6 to the aromatic polyamide on the kinetics of mesophase formation was observed.

  16. THE GAS TRANSPORT BEHAVIOR IN AROMATIC POLYESTER MEMBRANES

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian; SUN Qiushi; HOU Xiaohuai

    1996-01-01

    Six aromatic polyesters were prepared for gas separation membranes, and their permeation properties for hydrogen, oxygen, nitrogen, carbon dioxide, and methane were measured at 30℃ and 1 atmosphere by low pressure manometric method. The correlation between the gas transport behavior and molecular structure of aromatic polyester membrane is discussed. These data are interpreted qualitatively in terms of the calculated packing density, gas-polymer interaction, concentration of aryl bromine on backbone, and effect of silane group on main chain of polymer.

  17. Terahertz Spectroscopy of Biochars and Related Aromatic Compounds

    Science.gov (United States)

    Lepodise, L. M.; Horvat, J.; Lewis, R. A.

    2016-07-01

    A recent application of terahertz spectroscopy is to biochar, the agricultural charcoal produced by pyrolysis of various organic materials. Biochars simultaneously improve soil fertility and assist in carbon sequestration. Terahertz spectroscopy allows different biochars to be distinguished. However, the origin of the absorption features observed has not been clear. Given that biochar-based fertilizers are rich in aromatic compounds, we have investigated simple aromatic compounds as an approach to unravelling the complex biochar spectrum.

  18. Catalytic co-aromatization of ethanol and methane

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Aiguo; He, Peng; Yung, Matthew; Zeng, Hongbo; Qian, Hui; Song, Hua

    2016-12-01

    This study demonstrates the technical feasibility of simultaneously converting ethanol and methane into liquid hydrocarbons at mild reaction conditions (400 degrees C and 1 atm) over silver and/or zinc modified zeolite catalysts. After GC-MS analysis, it is worth noting that aromatics are the major compounds contained in the liquid product collected from the run when 1%Ag/ZSM-5, particularly after H2 pretreatment, is charged. Compared to the performance exhibited from the run with pure HZSM-5 support engaged, Ag addition into the HZSM-5 framework favors aromatics formation, which might be closely associated with better Ag dispersion and more abundance of strong surface acidic sites where aromatization might take place while Zn loading exerts a detrimental effect on the production of aromatics but promotes the ether generation possibly through dehydration reaction. Referred to that from its N2 counterpart, the increased aromatics formation of the collected liquid product when methane is present indicates that methane existence might facilitate ethanol aromatization. Moreover, combined with the increased carbon number in the formed aromatics from CH4 run when H2 run is referred and zero liquid formation from CH4-alone test as well as more prominent endothermic feature of methane run and more importantly the notably increased 13C signals in 13C NMR spectra of the liquid product collected during ethanol conversion under 13CH4 environment, all the observations suggest that methane might be activated nonoxidatively and converted into higher hydrocarbons, preferentially into aromatics if suitable catalyst is charged under the assistance of co-existing oxygenated hydrocarbon. The reported synergetic effect could potentially lead to the more economic utilization of abundant natural gas and cellulosic ethanol.

  19. Aromatic VOCs global influence in the ozone production

    Science.gov (United States)

    Cabrera-Perez, David; Pozzer, Andrea

    2016-04-01

    Aromatic hydrocarbons are a subgroup of Volatile Organic Compounds (VOCs) of special interest in the atmosphere of urban and semi-urban areas. Aromatics form a high fraction of VOCs, are highly reactive and upon oxidation they are an important source of ozone. These group of VOCs are released to the atmosphere by processes related to biomass burning and fossil fuel consumption, while they are removed from the atmosphere primarily by OH reaction and by dry deposition. In addition, a branch of aromatics (ortho-nitrophenols) produce HONO upon photolysis, which is responsible of certain amount of the OH recycling. Despite their importance in the atmosphere in anthropogenic polluted areas, the influence of aromatics in the ozone production remains largely unknown. This is of particular relevance, being ozone a pollutant with severe side effects on air quality, health and climate. In this work the atmospheric impacts at global scale of the most emitted aromatic VOCs in the gas phase (benzene, toluene, xylenes, ethylbenzene, styrene, phenol, benzaldehyde and trimethylbenzenes) are analysed and assessed. Specifically, the impact on ozone due to aromatic oxidation is estimated, as this is of great interest in large urban areas and can be helpful for developing air pollution control strategies. Further targets are the quantification of the NOx loss and the OH recycling due to aromatic oxidation. In order to investigate these processes, two simulations were performed with the numerical chemistry and climate simulation ECHAM/MESSy Atmospheric Chemistry (EMAC) model. The simulations compare two cases, one with ozone concentrations when aromatics are present or the second one when they are missing. Finally, model simulated ozone is compared against a global set of observations in order to better constrain the model accuracy.

  20. Terahertz Spectroscopy of Biochars and Related Aromatic Compounds

    Science.gov (United States)

    Lepodise, L. M.; Horvat, J.; Lewis, R. A.

    2016-12-01

    A recent application of terahertz spectroscopy is to biochar, the agricultural charcoal produced by pyrolysis of various organic materials. Biochars simultaneously improve soil fertility and assist in carbon sequestration. Terahertz spectroscopy allows different biochars to be distinguished. However, the origin of the absorption features observed has not been clear. Given that biochar-based fertilizers are rich in aromatic compounds, we have investigated simple aromatic compounds as an approach to unravelling the complex biochar spectrum.

  1. Key enzymes of the protocatechuate branch of the β-ketoadipate pathway for aromatic degradation in Corynebacterium glutamicum

    Institute of Scientific and Technical Information of China (English)

    SHEN; Xihui; LIU; Shuangjiang

    2005-01-01

    Although the protocatechuate branch of the β-ketoadipate pathway in Gram bacteria has been well studied, this branch is less understood in Gram+ bacteria. In this study,Corynebacterium glutamicum was cultivated with protocatechuate, p-cresol, vanillate and 4-hydroxybenzoate as sole carbon and energy sources for growth. Enzymatic assays indicated that growing cells on these aromatic compounds exhibited protocatechuate 3,4-dioxygenase activities. Data-mining of the genome of this bacterium revealed that the genetic locus ncg12314-ncg12315 encoded a putative protocatechuate 3,4-dioxygenase. The genes,ncg12314 and ncg12315, were amplified by PCR technique and were cloned into plasmid (pET21aP34D). Recombinant Escherichia coli strain harboring this plasmid actively expressed protocatechuate 3,4-dioxygenase activity. Further, when this locus was disrupted in C. glutamicum, the ability to degrade and assimilate protocatechuate, p-cresol, vanillate or 4-hydroxybenzoate was lost and protocatechuate 3,4-dioxygenase activity was disappeared. The ability to grow with these aromatic compounds and protocatechuate 3,4-dioxygenase activity of C.glutamicum mutant could be restored by gene complementation. Thus, it is clear that the key enzyme for ring-cleavage, protocatechuate 3,4-dioxygenase, was encoded by ncg12314 and ncg12315. The additional genes involved in the protocatechuate branch of the β-ketoadipate pathway were identified by mining the genome data publically available in the GenBank. The functional identification of genes and their unique organization in C. glutamicum provided new insight into the genetic diversity of aromatic compound degradation.

  2. Effect of sediment particle size on polycyclic aromatic hydrocarbon biodegradation: importance of the sediment-water interface.

    Science.gov (United States)

    Xia, Xinghui; Wang, Ran

    2008-01-01

    Mechanisms for the effects of sediment on the biodegradation of organic compounds in the aquatic environment are not clear. In this research, effects of sediment characteristics on biodegradation kinetics of chrysene and benzo[a]pyrene were studied by inoculating polycyclic aromatic hydrocarbon (PAH)-degrading bacteria. Because water and PAHs can pass a polytetrafluoroethylene membrane yet bacteria and sediment cannot, a membrane experiment was performed to compare the biodegradation rates of PAHs in water and at the sediment-water interface, providing direct evidence that the PAH biodegradation rate is enhanced by the presence of sediment. Biodegradation of PAHs in water-sediment systems was fitted to zero-order kinetics; the order of biodegradation rate in water-sediment systems with different sediment was fine silt > clay > coarse silt. Biodegradation of PAHs in water-sediment systems occurred mainly at the sediment-water interface. According to membrane experiment results, when the biodegradation kinetics was fit to a zero-order equation, the maximum specific growth rates of bacteria (1/d) at the sediment-water interface were approximately three- to fourfold those in the water phase. Furthermore, the associated mechanisms regarding the effect of sediment characteristics were analyzed by investigating the process of bacterial growth and the distribution of bacteria and PAHs between water and sediment phases.

  3. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    OpenAIRE

    NEENA GARG

    2015-01-01

    Lactic acid bacteria (LAB) is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LA...

  4. Thymidine kinase diversity in bacteria

    DEFF Research Database (Denmark)

    Sandrini, Michael; Clausen, A.R.; Munch-Petersen, B.

    2006-01-01

    Thymidine kinases (TKs) appear to be almost ubiquitous and are found in nearly all prokaryotes, eukaryotes, and several viruses. They are the key enzymes in thymidine salvage and activation of several anti-cancer and antiviral drugs. We show that bacterial TKs can be subdivided into 2 groups. The....... The TKs from Gram-positive bacteria are more closely related to the eukaryotic TK1 enzymes than are TKs from Gram-negative bacteria....

  5. A comparative effect of 3 disinfectants on heterotrophic bacteria, iron bacteria and sulfate-reducing bacteria

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The disinfection effect of chlorine dioxide, chlorine and their mixture on heterotrophic bacteria, iron bacteria and sulfate-reducing bacteria in circulating cooling water was studied. The results of the test indicated that high purity chlorine dioxide was the most effective biocide in the 3 disinfectants, and with a dosage of 0.5mg/L, chlorine dioxide could obtain perfect effect. High purity chloride dioxide could have the excellent effect with the pH value of 6 to 10, and could keep it within 72 h. Chlorine and their mixture couldn't reach the effect of chlorine dioxide.

  6. Aromatization of n-octane over Pd/C catalysts

    KAUST Repository

    Yin, Mengchen

    2013-01-01

    Gas-phase aromatization of n-octane was investigated using Pd/C catalyst. The objectives were to: (1) determine the effects of temperature (400-600 °C), weight hourly space velocity (WHSV) (0.8-∞), and hydrogen to hydrocarbon molar ratio (MR) (0-6) on conversion, selectivity, and yield (2) compare the activity of Pd/C with Pt/C and Pt/KL catalysts and (3) test the suitability of Pd/C for aromatization of different alkanes including n-hexane, n-heptane, and n-octane. Pd/C exhibited the best aromatization performance, including 54.4% conversion and 31.5% aromatics yield at 500 °C, WHSV = 2 h-1, and a MR of 2. The Pd/C catalyst had higher selectivity towards the preferred aromatics including ethylbenzene and xylenes, whereas Pt/KL had higher selectivity towards benzene and toluene. The results were somewhat consistent with adsorbed n-octane cyclization proceeding mainly through the six-membered ring closure mechanism. In addition, Pd/C was also capable of catalyzing aromatization of n-hexane and n-heptane. © 2012 Elsevier Ltd. All rights reserved.

  7. Bond length alternation and aromaticity in large annulenes

    Science.gov (United States)

    Choi, Cheol Ho; Kertesz, Miklos

    1998-04-01

    Properties of [4n] and [4n+2]annulenes were studied as a function of n for up to [66]annulene using Hartree-Fock and density functional theory in the generalized gradient approximation (DFT-GGA). In the 4n+2 series a "transition" from delocalized to localized structures occurs at 4n+2=30. Various indices of aromaticity, including NMR chemical shifts, bond localization, and aromatic stabilization energy (ASE) were monitored. π-bond localization occurs not due to a dramatic decrease of ASE as n increases, but rather as a result of a pseudo-Jahn-Teller (PJT) effect that sets in as the HOMO-LUMO gap decreases with increasing size. The NMR measures of aromaticity (difference between inner and outer 1H chemical shielding constants and the nucleus-independent chemical shifts, NICS) are reduced in the localized structures in comparison to the delocalized ones. The gradual nature of this "transition" is also implied by the relatively large values of the NMR measures of aromaticity that approach zero only gradually for larger size annulenes. Therefore intermediate size annulenes, such as [30]annulene are predicted to have a localized structure and aromatic properties at the same time showing the delocalized structure is not a necessary condition to be aromatic.

  8. Bio-Based Aromatic Epoxy Monomers for Thermoset Materials.

    Science.gov (United States)

    Ng, Feifei; Couture, Guillaume; Philippe, Coralie; Boutevin, Bernard; Caillol, Sylvain

    2017-01-18

    The synthesis of polymers from renewable resources is a burning issue that is actively investigated. Polyepoxide networks constitute a major class of thermosetting polymers and are extensively used as coatings, electronic materials, adhesives. Owing to their outstanding mechanical and electrical properties, chemical resistance, adhesion, and minimal shrinkage after curing, they are used in structural applications as well. Most of these thermosets are industrially manufactured from bisphenol A (BPA), a substance that was initially synthesized as a chemical estrogen. The awareness on BPA toxicity combined with the limited availability and volatile cost of fossil resources and the non-recyclability of thermosets implies necessary changes in the field of epoxy networks. Thus, substitution of BPA has witnessed an increasing number of studies both from the academic and industrial sides. This review proposes to give an overview of the reported aromatic multifunctional epoxide building blocks synthesized from biomass or from molecules that could be obtained from transformed biomass. After a reminder of the main glycidylation routes and mechanisms and the recent knowledge on BPA toxicity and legal issues, this review will provide a brief description of the main natural sources of aromatic molecules. The different epoxy prepolymers will then be organized from simple, mono-aromatic di-epoxy, to mono-aromatic poly-epoxy, to di-aromatic di-epoxy compounds, and finally to derivatives possessing numerous aromatic rings and epoxy groups.

  9. Bio-Based Aromatic Epoxy Monomers for Thermoset Materials

    Directory of Open Access Journals (Sweden)

    Feifei Ng

    2017-01-01

    Full Text Available The synthesis of polymers from renewable resources is a burning issue that is actively investigated. Polyepoxide networks constitute a major class of thermosetting polymers and are extensively used as coatings, electronic materials, adhesives. Owing to their outstanding mechanical and electrical properties, chemical resistance, adhesion, and minimal shrinkage after curing, they are used in structural applications as well. Most of these thermosets are industrially manufactured from bisphenol A (BPA, a substance that was initially synthesized as a chemical estrogen. The awareness on BPA toxicity combined with the limited availability and volatile cost of fossil resources and the non-recyclability of thermosets implies necessary changes in the field of epoxy networks. Thus, substitution of BPA has witnessed an increasing number of studies both from the academic and industrial sides. This review proposes to give an overview of the reported aromatic multifunctional epoxide building blocks synthesized from biomass or from molecules that could be obtained from transformed biomass. After a reminder of the main glycidylation routes and mechanisms and the recent knowledge on BPA toxicity and legal issues, this review will provide a brief description of the main natural sources of aromatic molecules. The different epoxy prepolymers will then be organized from simple, mono-aromatic di-epoxy, to mono-aromatic poly-epoxy, to di-aromatic di-epoxy compounds, and finally to derivatives possessing numerous aromatic rings and epoxy groups.

  10. Filtrating forms of soil bacteria

    Science.gov (United States)

    Van'kova, A. A.; Ivanov, P. I.; Emtsev, V. T.

    2013-03-01

    Filtrating (ultramicroscopic) forms (FF) of bacteria were studied in a soddy-podzolic soil and the root zone of alfalfa plants as part of populations of the most widespread physiological groups of soil bacteria. FF were obtained by filtering soil solutions through membrane filters with a pore diameter of 0.22 μm. It was established that the greater part of the bacteria in the soil and in the root zone of the plants has an ultramicroscopic size: the average diameter of the cells is 0.3 μm, and their length is 0.6 μm, which is significantly less than the cell size of banal bacteria. The number of FF varies within a wide range depending on the physicochemical conditions of the habitat. The FF number's dynamics in the soil is of a seasonal nature; i.e., the number of bacteria found increases in the summer and fall and decreases in the winter-spring period. In the rhizosphere of the alfalfa, over the vegetation period, the number of FF and their fraction in the total mass of the bacteria increase. A reverse tendency is observed in the rhizoplane. The morphological particularities (identified by an electron microscopy) and the nature of the FF indicate their physiological activity.

  11. Bioreporter bacteria for landmine detection

    Energy Technology Data Exchange (ETDEWEB)

    Burlage, R.S. [Oak Ridge National Lab., TN (United States); Youngblood, T. [Frisby Technologies, Aiken, SC (United States); Lamothe, D. [American Technologies, Inc., Huntsville, AL (United States). Ordnance/Explosives Environmental Services Div.

    1998-04-01

    Landmines (and other UXO) gradually leak explosive chemicals into the soil at significant concentrations. Bacteria, which have adapted to scavenge low concentrations of nutrients, can detect these explosive chemicals. Uptake of these chemicals results in the triggering of specific bacterial genes. The authors have created genetically recombinant bioreporter bacteria that detect small concentrations of energetic chemicals. These bacteria are genetically engineered to produce a bioluminescent signal when they contact specific explosives. A gene for a brightly fluorescent compound can be substituted for increased sensitivity. By finding the fluorescent bacteria, you find the landmine. Detection might be accomplished using stand-off illumination of the minefield and GPS technology, which would result in greatly reduced risk to the deminers. Bioreporter technology has been proven at the laboratory scale, and will be tested under field conditions in the near future. They have created a bacterial strain that detects sub-micromolar concentrations of o- and p-nitrotoluene. Related bacterial strains were produced using standard laboratory protocols, and bioreporters of dinitrotoluene and trinitrotoluene were produced, screening for activity with the explosive compounds. Response time is dependent on the growth rate of the bacteria. Although frill signal production may require several hours, the bacteria can be applied over vast areas and scanned quickly, producing an equivalent detection speed that is very fast. This technology may be applicable to other needs, such as locating buried explosives at military and ordnance/explosive manufacturing facilities.

  12. Cable Bacteria in Freshwater Sediments.

    Science.gov (United States)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus B; Dittmer, Anders Lindequist; Bjerg, Jesper Tataru; Trojan, Daniela; Schreiber, Lars; Damgaard, Lars Riis; Schramm, Andreas; Nielsen, Lars Peter

    2015-09-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures and electric fields indicated electron transfer between vertically separated anodic and cathodic half-reactions. Fluorescence in situ hybridization revealed the presence of Desulfobulbaceae filaments. In addition, in situ measurements of oxygen, pH, and electric potential distributions in the waterlogged banks of Giber Å demonstrated the presence of distant electric redox coupling in naturally occurring freshwater sediment. At the same site, filamentous Desulfobulbaceae with cable bacterium morphology were found to be present. Their 16S rRNA gene sequence placed them as a distinct sister group to the known marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary origin of the cable phenotype within Desulfobulbaceae with subsequent diversification into a freshwater and a marine lineage.

  13. Bioremediation a potential approach for soil contaminated with polycyclic aromatic hydrocarbons: An Overview

    Directory of Open Access Journals (Sweden)

    Norzila Othman

    2011-12-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs represent a group of priority pollutants which are present at high concentration in soils of many industrially contaminated sites. Standards and criteria for the remediation of soils contaminated with PAHs vary widely between countries. Bioremediation has gained preference as a technology for remediation contaminated sites as it is less expensive and more environmental friendly. Bioremediation utilizes microorganisms to degrade PAHs to less toxic compounds. This technology degrades contaminants through natural biodegradation mechanisms or enhanced biodegradation mechanism and can be performed in-situ or ex-situ under aerobic or anaerobic conditions. The purpose of this paper is to highlight potential of using isolated strains from municipal sludge on soil remediation. Several indigenous bacteria from municipal sludge namely genus Micrococus, Sphingomonas, and Corynebacterium demonstrated a high removal rate of PAHs with more than 80% of lower molecular weight of PAHs degraded after one week incubation. Laboratory studies had established that these genus able to degrade PAHs on contaminated soil. The successful application of bacteria to the bioremediation of PAHs contaminated sites requires a deeper understanding of how microbial PAH degradation proceeds. An overview of research focusing on biodegradation of PAHs will be presented.

  14. Biodegradation of the low concentration of polycyclic aromatic hydrocarbons in soil by microbial consortium during incubation.

    Science.gov (United States)

    Li, Xiaojun; Lin, Xin; Li, Peijun; Liu, Wan; Wang, Li; Ma, Fang; Chukwuka, K S

    2009-12-30

    The biodegradation of polycyclic aromatic hydrocarbons (PAHs) (8.15 mg PAHs kg(-1) soil) in aged contaminated soil by isolated microbial consortium (five fungi and three bacteria) during the incubation of 64d is reported. The applied treatments were: (1) biodegradation by adding microbial consortium in sterile soils (BM); (2) biodegradation by adding microbial consortium in non-sterile soils (BMN); and (3) biodegradation by in situ "natural" microbes in non-sterile soils (BNN). The fungi in BM and BMN soils grew rapidly 0-4d during the incubation and then reached a relative equilibrium. In contrast the fungi in BNN soil remained at a constant level for the entire time. Comparison with the fungi, the bacteria in BNN soils grew rapidly during the incubation 0-2d and then reached a relative equilibrium, and those in BM and BMN soils grew slowly during the incubation of 64 d. After 64 d of incubation, the PAH biodegradations were 35%, 40.7% and 41.3% in BNN, BMN and BM, respectively. The significant release of sequestrated PAHs in aged contaminated soil was observed in this experiment, especially in the BM soil. Therefore, although bioaugmentation of introduced microbial consortium increased significantly the biodegradation of PAHs in aged contaminated soil with low PAH concentration, the creation of optimum of the environmental situation might be the best way to use bioremediation successfully in the field.

  15. Pyrosequence analysis of bacterial communities in aerobic bioreactors treating polycyclic aromatic hydrocarbon-contaminated soil.

    Science.gov (United States)

    Singleton, David R; Richardson, Stephen D; Aitken, Michael D

    2011-11-01

    Two aerobic, lab-scale, slurry-phase bioreactors were used to examine the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil and the associated bacterial communities. The two bioreactors were operated under semi-continuous (draw-and-fill) conditions at a residence time of 35 days, but one was fed weekly and the other monthly. Most of the quantified PAHs, including high-molecular-weight compounds, were removed to a greater extent in the weekly-fed bioreactor, which achieved total PAH removal of 76%. Molecular analyses, including pyrosequencing of 16S rRNA genes, revealed significant shifts in the soil bacterial communities after introduction to the bioreactors and differences in the abundance and types of bacteria in each of the bioreactors. The weekly-fed bioreactor displayed a more stable bacterial community with gradual changes over time, whereas the monthly-fed bioreactor community was less consistent and may have been more strongly influenced by the influx of untreated soil during feeding. Phylogenetic groups containing known PAH-degrading bacteria previously identified through stable-isotope probing of the untreated soil were differentially affected by bioreactor conditions. Sequences from members of the Acidovorax and Sphingomonas genera, as well as the uncultivated "Pyrene Group 2" were abundant in the bioreactors. However, the relative abundances of sequences from the Pseudomonas, Sphingobium, and Pseudoxanthomonas genera, as well as from a group of unclassified anthracene degraders, were much lower in the bioreactors compared to the untreated soil.

  16. Reduction of Aromatic α-Keto Esters by Commercially Available Zinc Dust and Ammonium Formate:Formation of Aromatic a-Hydroxy Esters

    Institute of Scientific and Technical Information of China (English)

    CHEN Gang; YAO Guo-xin; SONG Guang-wei; ZHU Jin-tao

    2011-01-01

    Various aromatic α-keto esters were rapidly and selectively reduced to aromatic α-hydroxy esters by commercially available zinc dust and ammonium formate in the presence of other functional groups such as halogens,methoxy and esters.

  17. Untangling the multiple monooxygenases of Mycobacterium chubuense strain NBB4, a versatile hydrocarbon degrader.

    Science.gov (United States)

    Coleman, Nicholas V; Yau, Sheree; Wilson, Neil L; Nolan, Laura M; Migocki, Margaret D; Ly, Mai-Anh; Crossett, Ben; Holmes, Andrew J

    2011-06-01

    Mycobacterium strain NBB4 was isolated on ethene as part of a bioprospecting study searching for novel monooxygenase (MO) enzymes of interest to biocatalysis and bioremediation. Previous work indicated that strain NBB4 contained an unprecedented diversity of MO genes, and we hypothesized that each MO type would support growth on a distinct hydrocarbon substrate. Here, we attempted to untangle the relationships between MO types and hydrocarbon substrates. Strain NBB4 was shown to grow on C2 -C4 alkenes and C2 -C16 alkanes. Complete gene clusters encoding six different monooxygenases were recovered from a fosmid library, including homologues of ethene MO (etnABCD), propene MO (pmoABCD), propane MO (smoABCD), butane MO (smoXYB1C1Z), cytochrome P450 (CYP153; fdx-cyp-fdr) and alkB (alkB-rubA1-rubA2). Catabolic enzymes involved in ethene assimilation (EtnA, EtnC, EtnD, EtnE) and alkane assimilation (alcohol and aldehyde dehydrogenases) were identified by proteomics, and we showed for the first time that stress response proteins (catalase/peroxidase, chaperonins) were induced by growth on C2 -C5 alkanes and ethene. Surprisingly, none of the identified MO genes could be specifically associated with oxidation of small alkanes, and thus the nature of the gaseous alkane MO in NBB4 remains mysterious.

  18. Chlorinated Hydrocarbon Degradation in Plants: Mechanisms and Enhancement of Phytoremediation of Groundwater Contamination

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Strand

    2004-09-27

    The research objectives for this report are: (1) Transform poplar and other tree species to extend and optimize chlorinated hydrocarbon (CHC) oxidative activities. (2) Determine the mechanisms of CHC oxidation in plants. (3) Isolate the genes responsible for CHC oxidation in plants. We have made significant progress toward an understanding of the biochemical mechanism of CHC transformation native to wild-type poplar. We have identified chloral, trichloroethanol, trichloroacetic acid, and dichloroacetic acid as products of TCE metabolism in poplar plants and in tissue cultures of poplar cells.(Newman et al. 1997; Newman et al. 1999) Use of radioactively labeled TCE showed that once taken up and transformed, most of the TCE was incorporated into plant tissue as a non-volatile, unextractable residue.(Shang et al. 2001; Shang and Gordon 2002) An assay for this transformation was developed and validated using TCE transformation by poplar suspension cells. Using this assay, it was shown that two different activities contribute to the fixation of TCE by poplar cells: one associated with cell walls and insoluble residues, the other associated with a high molecular weight, heat labile fraction of the cell extract, a fixation that was apparently catalyzed by plant enzymes.

  19. ASSESSMENT OF PETROLEUM HYDROCARBON DEGRADATION FROM SOIL AND TARBALL BY FUNGI

    Directory of Open Access Journals (Sweden)

    Sakineh Lotfinasabasl1, V. R.Gunale1, N. S. Rajurkar 1, 2

    2012-06-01

    Full Text Available Four fungi strains viz. Aspergillus niger, Aspergillus terreus, Rhizopus sp and Penicillium sp were isolated from soil and tarball samples collected from mangrove forest of Alibaug and Akshi coastal area, Maharashtra, India. These strains were assessed for their degradation capability of petroleum hydrocarbons measuring growth diameter in Potato Dextrose Agar (PDA solid media for different concentrations of kerosene (5%- 20% (v/v. Rhizopus sp showed the highest growth diameter in 5% kerosene and Aspergillus niger showed the highest growth diameter in 20% kerosene while, penicillium sp showed the lowest growth diameter at all the concentrations of kerosene as compared to other three strains. The bioremediation of 20% oil contaminated soil by different fungi strains was found in the order Aspergillus niger> Rhizopus sp> Aspergillus terreus > Penicillium sp. In order to determine the effect of mixed fungal culture in contrast with single one, studies were carried out in 10% (v/v oil contaminated PDA media. It was observed that a mix culture consisting of penicillium sp, Rhizopus sp and Aspergillus terreus showed highest growth diameter.

  20. Chlorinated Hydrocarbon Degradation in Plants: Mechanisms and Enhancement of Phytoremediation of Groundwater Contamination

    Energy Technology Data Exchange (ETDEWEB)

    Strand, Stuart E.

    2002-06-01

    Several varieties of transgenic poplar containing cytochrome P-450 2E1 have been constructed and are undergoing tests. Strategies for improving public acceptance and safety of transgenic poplar for chlorinated hydrocarbon phytoremediation are being developed. We have discovered a unique rhizobium species that lives within the stems of poplar and we are investigating whether this bacterium contributes nitrogen fixed from the air to the plant and whether this endophyte could be used to introduce genes into poplar. Studies of the production of chloride ion from TCE have shown that our present P-450 constructs did not produce chloride more rapidly than wild type plants. Follow-up studies will determine if there are other rate limiting downstream steps in TCE metabolism in plants. Studies of the metabolism of carbon tetrachloride in poplar cells have provided evidence that the native plant metabolism is due to the activity of oxidative enzymes similar to the mammalian cytochrome P-450 2E1.

  1. Kinetics of Chlorinated Hydrocarbon Degradation by Methylosinus trichosporium OB3b and Toxicity of Trichloroethylene

    NARCIS (Netherlands)

    Oldenhuis, Roelof; Oedzes, Johannes Y.; Waarde, Jacob J. van der; Janssen, Dick B.

    1991-01-01

    The kinetics of the degradation of trichloroethylene (TCE) and seven other chlorinated aliphatic hydrocarbons by Methylosinus trichosporium OB3b were studied. All experiments were performed with cells grown under copper stress and thus expressing soluble methane monooxygenase. Compounds that were re

  2. Isolation and Identification of Concrete Environment Bacteria

    Science.gov (United States)

    Irwan, J. M.; Anneza, L. H.; Othman, N.; Husnul, T.; Alshalif, A. F.

    2016-07-01

    This paper presents the isolation and molecular method for bacteria identification through PCR and DNA sequencing. Identification of the bacteria species is required in order to fully utilize the bacterium capability for precipitation of calcium carbonate in concrete. This process is to enable the addition of suitable catalyst according to the bacterium enzymatic pathway that is known through the bacteria species used. The objective of this study is to isolate, enriched and identify the bacteria species. The bacteria in this study was isolated from fresh urine and acid mine drainage water, Kota Tinggi, Johor. Enrichment of the isolated bacteria was conducted to ensure the bacteria survivability in concrete. The identification of bacteria species was done through polymerase chain reaction (PCR) and rRDNA sequencing. The isolation and enrichment of the bacteria was done successfully. Whereas, the results for bacteria identification showed that the isolated bacteria strains are Bacillus sp and Enterococus faecalis.

  3. Crude oil biodegradation by a mixed bacterial culture

    Energy Technology Data Exchange (ETDEWEB)

    Van Hamme, J.D.

    2000-07-01

    Mixed cultures with broad substrate specificity usually form the basis for biological methods used for the remediation of petroleum hydrocarbon-contaminated wastes. Bow River crude oil was used as a model substrate for the study of microbe-microbe and microbe-substrate interactions in batch fermentation systems. Substrate availability limited the mixed-bacterial culture due to hydrocarbon insolubility. A method of improving biodegradation through the use of chemical surfactants was tested. A hydrophile-lipophile balance of 13 led to optimum enhancement at supra-critical micellization concentrations not exceeding a critical level, as indicated by the results of a detailed study with nonylphenol ethoxylates. A broad variety of trypticase soy agar-culturable bacteria was contained in the culture. Initially, Pseudomonas Flavimonas and Stenotrophomonas spp. dominated in the fermentations with different hydrocarbon mixtures. The lag time of Stenotrophomonas sp. and exposure to Bow River saturates selected for an Acinetobacter calcoacetius strain were increased by a chemical surfactant. Following prolonged incubation, a greater variety of mainly non-hydrocarbon degrading bacteria were isolated in each case. Low molecular weight volatile hydrocarbons were degraded in closed systems and the greatest activity from the culture occurred against the saturate and aromatic fractions. To monitor volatile hydrocarbon degradation in live cultures at 30 degrees Celsius, a rapid and sensitive solid phase microextraction methodology was developed. Only the cultures grown on crude oil in sealed flasks, or in open flasks amended with yeast extract retained their volatile hydrocarbon-degrading capabilities. Correlated with reduced proportions of hydrocarbon-degrading bacteria in biodegradation flasks, metabolic capacity decreased with inoculum age. The degradation hierarchy and chemical surfactant effects were confirmed by pure and co-culture studies. The presence of a chemical surfactant

  4. Closed-Shell Polycyclic Aromatic Hydrocarbon Cations: A New Category of Interstellar Polycyclic Aromatic Hydrocarbons

    Science.gov (United States)

    Hudgins, Douglas M.; Bauschlicher, Charles W., Jr.; Allamandola, Louis J.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Density functional theory has been employed to calculate the harmonic frequencies and intensities of a range of polycyclic aromatic hydrocarbon (PAH) cations that explore both size and electronic structure effects of the infrared spectroscopic properties of these species. The sample extends the size range of PAH species considered to more than 50 carbon atoms and includes several representatives from each of two heretofore unexplored categories of PAH cations: (1) fully benzenoid PAH cations whose carbon skeleton is composed of an odd number of carbon atoms (C(sub odd) PAHs); and (2) protonated PAH cations (HPAH+). Unlike the radical electronic structures of the PAH cations that have been the subject of previous theoretical and experimental work, the species in these two classes have a closed-shell electronic configuration. The calculated spectra of circumcoronene, C54H18 in both neutral and (radical) cationic form are also reported and compared with those of the other species. Overall, the C(sub odd) PAHs spectra are dominated by strong CC stretching modes near 1600 cm(exp -1) and display spectra that are remarkably insensitive to molecular size. The HPAH+ species evince a more complex spectrum consistent with the added contributions of aliphatic modes and their generally lower symmetry. Finally, for both classes of closed-shell cations, the intensity of the aromatic CH stretching modes is found to increase with molecular size far out of proportion with the number of CH groups, approaching a value more typical of neutral PAHs for the largest species studied.

  5. Arginine-aromatic interactions and their effects on arginine-induced solubilization of aromatic solutes and suppression of protein aggregation

    KAUST Repository

    Shah, Dhawal

    2011-09-21

    We examine the interaction of aromatic residues of proteins with arginine, an additive commonly used to suppress protein aggregation, using experiments and molecular dynamics simulations. An aromatic-rich peptide, FFYTP (a segment of insulin), and lysozyme and insulin are used as model systems. Mass spectrometry shows that arginine increases the solubility of FFYTP by binding to the peptide, with the simulations revealing the predominant association of arginine to be with the aromatic residues. The calculations further show a positive preferential interaction coefficient, Γ XP, contrary to conventional thinking that positive Γ XP\\'s indicate aggregation rather than suppression of aggregation. Simulations with lysozyme and insulin also show arginine\\'s preference for aromatic residues, in addition to acidic residues. We use these observations and earlier results reported by us and others to discuss the possible implications of arginine\\'s interactions with aromatic residues on the solubilization of aromatic moieties and proteins. Our results also highlight the fact that explanations based purely on Γ XP, which measures average affinity of an additive to a protein, could obscure or misinterpret the underlying molecular mechanisms behind additive-induced suppression of protein aggregation. © 2011 American Institute of Chemical Engineers (AIChE).

  6. Toxicity of five anilines to crustaceans, protozoa and bacteria

    Directory of Open Access Journals (Sweden)

    MARILIIS SIHTMÄE

    2010-09-01

    Full Text Available Aromatic amines (anilines and related derivates are an important class of environmental pollutants that can be released to the aquatic environment as industrial effluents or as breakdown products of pesticides and dyes. The toxicity of aniline, 2-chloroaniline, 3-chloroaniline, 4-chloroaniline and 3,5-dichloroaniline towards a multitrophic test battery comprised of bacteria Aliivibrio fischeri (formerly Vibrio fischeri, a ciliated protozoan Tetrahymena thermophila and two crustaceans (Daphnia magna and Thamnocephalus platyurus were investigated. Under the applied test conditions, the toxicity of the anilines notably varied among the test species. The bacteria and protozoa were much less sensitive towards the anilines than the crustaceans: EC50 values 13–403 mg L-1 versus 0.13–15.2 mg L-1. No general tendency between toxicity and the chemical structure of the anilines (the degree of chloro-substitution and the position of the chloro-substituents was found in the case of all the tested aquatic species. The replacement of the artificial test medium (ATM by the river water remarkably decreased the toxicity of anilines to crustaceans but not to protozoa. This research is part of the EU 6th Framework Integrated Project OSIRIS, in which ecotoxicogenomic studies of anilines (e.g., for Daphnia magna will also be performed that may help to clarify the mechanisms of toxicity of different anilines.

  7. Partition of polycyclic aromatic hydrocarbons on organobentonites

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of organobentonites synthesized by exchanging organiccation such as dodecyltri-methylammonium (DTMA),benzyldimethyltetradecylammonium (BDTDA), cetyltrimethyl-ammonium (CTMA), octodeyltrimethylammonium (OTMA) on bentonite. The optimal condition, properties and mechanisms for the organobentonites to sorb phenanthrene, anthracene, naphthalene, acenaphthene in water were investigated in detail. The partition behavior was determined for four polycyclic aromatic hydrocarbons (PAHs), such as naphthalene, phenanthrene, anthracene and acenaphthene, from water to a series of organobentonites. The interlayer spacings and organic carbon contents of organobentonites, removal rate and sorption capacities for organobentonites to treat phenanthrene,anthracene, naphthalene, acenaphthene were correlated to the length of alkyl chains and the amounts of cation surfactant exchanged on Foundation item: the bentonite. Phenanthrene, anthracene, naphthalene, and acenaphthene sorption to organobentonites were characterized by linear isotherms, indicating solute partition between water and the organic phase composed of the large alkyl functional groups of quaternary ammonium cations. PAHs distribution coefficients (Kd)between organobentonites and water were proportional to the organic carbon contents of organobentonites. However, the partition coefficients (Koc) were nearly constants for PAHs in the system of organobentonite-water. The Koc of phenanthrene, anthracene,naphthalene, acenaphthene were 2.621x105, 2.106x105, 2.247x104,5.085x104, respectively. The means Koc values on the organobentonites are about ten to twenty times larger than the values on the soils/sediments, what is significant prerequisite for organobentonite to apply to remediation of pollution soil and groundwater. The sorption mechanism was also evaluated from octanol-water partition coefficients and aqueous solubility of PAHs. The correlations between lgKoc and 1gkow, 1gKoc and 1gS for PAHs in the system of water

  8. [Genetic resources of nodule bacteria].

    Science.gov (United States)

    Rumiantseva, M L

    2009-09-01

    Nodule bacteria (rhizobia) form highly specific symbiosis with leguminous plants. The efficiency of accumulation of biological nitrogen depends on molecular-genetic interaction between the host plant and rhizobia. Genetic characteristics of microsymbiotic strains are crucial in developing highly productive and stress-resistant symbiotic pairs: rhizobium strain-host plant cultivar (species). The present review considers the issue of studying genetic resources of nodule bacteria to identify genes and their blocks, responsible for the ability of rhizobia to form highly effective symbiosis in various agroecological conditions. The main approaches to investigation of intraspecific and interspecific genetic and genomic diversity of nodule bacteria are considered, from MLEE analysis to the recent methods of genomic DNA analysis using biochips. The data are presented showing that gene centers of host plants are centers of genetic diversification of nodule bacteria, because the intraspecific polymorphism of genetic markers of the core and the accessory rhizobial genomes is extremely high in them. Genotypic features of trapped and nodule subpopulations of alfalfa nodule bacteria are discussed. A survey of literature showed that the genomes of natural strains in alfalfa gene centers exhibit significant differences in genes involved in control of metabolism, replication, recombination, and the formation of defense response (hsd genes). Natural populations of rhizobia are regarded as a huge gene pool serving as a source of evolutionary innovations.

  9. A novel aromatic oil compound inhibits microbial overgrowth on feet: a case study

    Directory of Open Access Journals (Sweden)

    Misner Bill D

    2007-07-01

    Full Text Available Abstract Background Athlete's Foot (Tinea pedis is a form of ringworm associated with highly contagious yeast-fungi colonies, although they look like bacteria. Foot bacteria overgrowth produces a harmless pungent odor, however, uncontrolled proliferation of yeast-fungi produces small vesicles, fissures, scaling, and maceration with eroded areas between the toes and the plantar surface of the foot, resulting in intense itching, blisters, and cracking. Painful microbial foot infection may prevent athletic participation. Keeping the feet clean and dry with the toenails trimmed reduces the incidence of skin disease of the feet. Wearing sandals in locker and shower rooms prevents intimate contact with the infecting organisms and alleviates most foot-sensitive infections. Enclosing feet in socks and shoes generates a moisture-rich environment that stimulates overgrowth of pungent both aerobic bacteria and infectious yeast-fungi. Suppression of microbial growth may be accomplished by exposing the feet to air to enhance evaporation to reduce moistures' growth-stimulating effect and is often neglected. There is an association between yeast-fungi overgrowths and disabling foot infections. Potent agents virtually exterminate some microbial growth, but the inevitable presence of infection under the nails predicts future infection. Topical antibiotics present a potent approach with the ideal agent being one that removes moisture producing antibacterial-antifungal activity. Severe infection may require costly prescription drugs, salves, and repeated treatment. Methods A 63-y female volunteered to enclose feet in shoes and socks for 48 hours. Aerobic bacteria and yeast-fungi counts were determined by swab sample incubation technique (1 after 48-hours feet enclosure, (2 after washing feet, and (3 after 8-hours socks-shoes exposure to a aromatic oil powder-compound consisting of arrowroot, baking soda, basil oil, tea tree oil, sage oil, and clove oil. Conclusion

  10. Construction of a plant-microbe phytoremediation system: combination of vetiver grass with a functional endophytic bacterium, Achromobacter xylosoxidans F3B, for aromatic pollutants removal.

    Science.gov (United States)

    Ho, Ying-Ning; Hsieh, Ju-Liang; Huang, Chieh-Chen

    2013-10-01

    The endophytic bacterial strain Achromobacter xylosoxidans F3B, which was able to utilize aromatic compounds as a sole carbon source, was inoculated into vetiver grass in this study. A real-time PCR detection method has been developed for confirming the stability of F3B in plants and DGGE profiles were conducted for examining the diversity of endophytes during the remediation process. These results showed that the endophytic bacteria strain F3B could maintain a stable population in plant roots without largely interfering with the diversity of native endophytes. Furthermore, the strain F3B could protect plants against toluene stress and maintain chlorophyll content of leaves, and a 30% reduction of evapotranspiration through vetiver leaves was observed. Our results demonstrate the potential to improve phytoremediation of aromatic pollutants by inoculating functional endophytic bacterial strains.

  11. IDENTIFICATION OF BACTERIA IN LATEX PAINTS

    Directory of Open Access Journals (Sweden)

    Rojas, J.

    2008-01-01

    Full Text Available The bacteria are prokaryote organisms with a high capacity to colonize many types of habits. This research was developed with the object to identify extremophiles bacteria presents in latex paint. The bacteria were cultivated in culture mediums TSA, Blood Agar, Mc Conkey and finally the biochemical proof API-NF® for bacteria's isolation and identification, respectively. Characterization showed bacterial profile of Pasteurella sp. Hypothesis that could be found extremophiles bacteria in latex paint were demonstrated.

  12. Methylotrophic bacteria in sustainable agriculture.

    Science.gov (United States)

    Kumar, Manish; Tomar, Rajesh Singh; Lade, Harshad; Paul, Diby

    2016-07-01

    Excessive use of chemical fertilizers to increase production from available land has resulted in deterioration of soil quality. To prevent further soil deterioration, the use of methylotrophic bacteria that have the ability to colonize different habitats, including soil, sediment, water, and both epiphytes and endophytes as host plants, has been suggested for sustainable agriculture. Methylotrophic bacteria are known to play a significant role in the biogeochemical cycle in soil ecosystems, ultimately fortifying plants and sustaining agriculture. Methylotrophs also improve air quality by using volatile organic compounds such as dichloromethane, formaldehyde, methanol, and formic acid. Additionally, methylotrophs are involved in phosphorous, nitrogen, and carbon cycling and can help reduce global warming. In this review, different aspects of the interaction between methylotrophs and host plants are discussed, including the role of methylotrophs in phosphorus acquisition, nitrogen fixation, phytohormone production, iron chelation, and plant growth promotion, and co-inoculation of these bacteria as biofertilizers for viable agriculture practices.

  13. Chitin Degradation In Marine Bacteria

    DEFF Research Database (Denmark)

    Paulsen, Sara; Machado, Henrique; Gram, Lone

    2015-01-01

    Introduction: Chitin is the most abundant polymer in the marine environment and the second most abundant in nature. Chitin does not accumulate on the ocean floor, because of microbial breakdown. Chitin degrading bacteria could have potential in the utilization of chitin as a renewable carbon...... and nitrogen source in the fermentation industry.Methods: Here, whole genome sequenced marine bacteria were screened for chitin degradation using phenotypic and in silico analyses.Results: The in silico analyses revealed the presence of three to nine chitinases in each strain, however the number of chitinases...... chitin regulatory system.Conclusions: This study has provided insight into the ecology of chitin degradation in marine bacteria. It also served as a basis for choosing a more efficient chitin degrading production strain e.g. for the use of chitin waste for large-scale fermentations....

  14. Impact of dietary aromatic amino acids on osteoclastic activity.

    Science.gov (United States)

    Refaey, Mona El; Zhong, Qing; Ding, Ke-Hong; Shi, Xing-Ming; Xu, Jianrui; Bollag, Wendy B; Hill, William D; Chutkan, Norman; Robbins, Richard; Nadeau, Hugh; Johnson, Maribeth; Hamrick, Mark W; Isales, Carlos M

    2014-08-01

    We had shown that aromatic amino acid (phenylalanine, tyrosine, and tryptophan) supplementation prevented bone loss in an aging C57BL/6 mice model. In vivo results from the markers of bone breakdown suggested an inhibition of osteoclastic activity or differentiation. To assess osteoclastic differentiation, we examined the effects of aromatic amino acids on early /structural markers as vitronectin receptor, calcitonin receptor, and carbonic anhydrase II as well as, late/functional differentiation markers; cathepsin K and matrix metalloproteinase 9 (MMP-9). Our data demonstrate that the aromatic amino acids down-regulated early and late osteoclastic differentiation markers as measured by real time PCR. Our data also suggest a link between the vitronectin receptor and the secreted cathepsin K that both showed consistent effects to the aromatic amino acid treatment. However, the non-attachment related proteins, calcitonin receptor, and carbonic anhydrase II, demonstrated less consistent effects in response to treatment. Our data are consistent with aromatic amino acids down-regulating osteoclastic differentiation by suppressing remodeling gene expression thus contributing initially to the net increase in bone mass seen in vivo.

  15. Degradation of aromatic compounds in plants grown under aseptic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mithaishvili, T.; Ugrekhelidze, D.; Tsereteli, B.; Sadunishvili, T.; Kvesitadze, G. [Durmishidze Inst. of Biochemistry and Biotechnology, Academy of Sciences of Georgia, Tbilisi (Georgia); Scalla, R. [Lab. des Xenobiotiques, INRA, Toulouse (France)

    2005-02-01

    The aim of the work is to investigate the ability of higher plants to absorb and detoxify environmental pollutants - aromatic compounds via aromatic ring cleavage. Transformation of {sup 14}C specifically labelled benzene derivatives, [1-6-{sup 14}C]-nitrobenzene, [1-6-{sup 14}C]-aniline, [1-{sup 14}C]- and [7-{sup 14}C]-benzoic acid, in axenic seedlings of maize (Zea mays L.), kidney bean (Phaseolus vulgaris L.), pea (Pisum sativum L.) and pumpkin (Cucurbita pepo L.) were studied. After penetration in plants, the above xenobiotics are transformed by oxidative or reductive reactions, conjugation with cell endogenous compounds, and binding to biopolymers. The initial stage of oxidative degradation consists in hydroxylation reactions. The aromatic ring can then be cleaved and degraded into organic acids of the Krebs cycle. Ring cleavage is accompanied by {sup 14}CO{sub 2} evolution. Aromatic ring cleavage in plants has thus been demonstrated for different xenobiotics carrying different substitutions on their benzene ring. Conjugation with low molecular peptides is the main pathway of aromatic xenobiotics detoxification. Peptide conjugates are formed both by the initial xenobiotics (except nitrobenzene) and by intermediate transformation products. The chemical nature of the radioactive fragment and the amino acid composition of peptides participating in conjugation were identified. (orig.)

  16. Global atmospheric budget of simple monocyclic aromatic compounds

    Science.gov (United States)

    Cabrera-Perez, David; Taraborrelli, Domenico; Sander, Rolf; Pozzer, Andrea

    2016-06-01

    The global atmospheric budget and distribution of monocyclic aromatic compounds is estimated, using an atmospheric chemistry general circulation model. Simulation results are evaluated with an ensemble of surface and aircraft observations with the goal of understanding emission, production and removal of these compounds.Anthropogenic emissions provided by the RCP database represent the largest source of aromatics in the model (≃ 23 TgC year-1) and biomass burning from the GFAS inventory the second largest (≃ 5 TgC year-1). The simulated chemical production of aromatics accounts for ≃ 5 TgC year-1. The atmospheric burden of aromatics sums up to 0.3 TgC. The main removal process of aromatics is photochemical decomposition (≃ 27 TgC year-1), while wet and dry deposition are responsible for a removal of ≃ 4 TgC year-1.Simulated mixing ratios at the surface and elsewhere in the troposphere show good spatial and temporal agreement with the observations for benzene, although the model generally underestimates mixing ratios. Toluene is generally well reproduced by the model at the surface, but mixing ratios in the free troposphere are underestimated. Finally, larger discrepancies are found for xylenes: surface mixing ratios are not only overestimated but also a low temporal correlation is found with respect to in situ observations.

  17. Distributions of polycyclic aromatic hydrocarbons and alkylated polycyclic aromatic hydrocarbons in Osaka Bay, Japan.

    Science.gov (United States)

    Miki, Shizuho; Uno, Seiichi; Ito, Kazuki; Koyama, Jiro; Tanaka, Hiroyuki

    2014-08-30

    Contaminations in sediments by polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs were investigated at 44 sites in Osaka Bay, Japan. Concentrations of total PAHs and alkylated PAHs were in the range 6.40-7800 ng/g dry weights and 13.7-1700 ng/g dry weights, respectively. The PAH concentrations tended to be higher along the shoreline in the vicinities of big ports, industrialized areas, and densely populated regions such as the cities of Osaka and Kobe. The major sources appeared to be pyrogenic or both pyrogenic and petrogenic at most of the sites. PAH concentrations were remarkably high at a site near Kobe, where the concentrations of dibenzo(a,h)anthracene and benzo(g,h,i)perylene exceeded the effects-range-medium concentration and eight PAHs were above the corresponding effects-range-low concentrations. Those PAHs may have been derived from the great fire associated with the large earthquake in 1995.

  18. Adaptation, Bacteria and Maxwell's Demons

    Science.gov (United States)

    Galajda, Peter; Keymer, Juan E.; Austin, Robert H.

    2007-03-01

    We propose a method to study the adaptation of bacterial populations with an asymmetric wall of Maxwell Demon openings. A Maxwell Demon opening is a funnel which is easier to enter than to leave. The interaction of swimming cells with such a Maxwell Demon Wall results in a population density separation, in apparent (but not real) violation of the Second Law of Thermodynamics, as we will show. Bacteria can be exposed to spatial challenges in order to move to e. g. higher food levels. The question we address in these experiments is: do the bacteria adapt and overcome the Maxwell Demon Wall?

  19. Aromatic claw: A new fold with high aromatic content that evades structural prediction.

    Science.gov (United States)

    Sachleben, Joseph R; Adhikari, Aashish N; Gawlak, Grzegorz; Hoey, Robert J; Liu, Gaohua; Joachimiak, Andrzej; Montelione, Gaetano T; Sosnick, Tobin R; Koide, Shohei

    2017-02-01

    We determined the NMR structure of a highly aromatic (13%) protein of unknown function, Aq1974 from Aquifex aeolicus (PDB ID: 5SYQ). The unusual sequence of this protein has a tryptophan content five times the normal (six tryptophan residues of 114 or 5.2% while the average tryptophan content is 1.0%) with the tryptophans occurring in a WXW motif. It has no detectable sequence homology with known protein structures. Although its NMR spectrum suggested that the protein was rich in β-sheet, upon resonance assignment and solution structure determination, the protein was found to be primarily α-helical with a small two-stranded β-sheet with a novel fold that we have termed an Aromatic Claw. As this fold was previously unknown and the sequence unique, we submitted the sequence to CASP10 as a target for blind structural prediction. At the end of the competition, the sequence was classified a hard template based model; the structural relationship between the template and the experimental structure was small and the predictions all failed to predict the structure. CSRosetta was found to predict the secondary structure and its packing; however, it was found that there was little correlation between CSRosetta score and the RMSD between the CSRosetta structure and the NMR determined one. This work demonstrates that even in relatively small proteins, we do not yet have the capacity to accurately predict the fold for all primary sequences. The experimental discovery of new folds helps guide the improvement of structural prediction methods.

  20. Environmental Behaviors and Toxicities of Polycyclic Aromatic Hydrocarbons and Nitropolycyclic Aromatic Hydrocarbons.

    Science.gov (United States)

    Hayakawa, Kazuichi

    2016-01-01

    Airborne particulate matter (PM) has been collected at four cities in Japan starting in the late 1990s, at five or more major cities in China, Korea and Russia starting in 2001 and at the Noto Peninsula starting in 2004. Nine polycyclic aromatic hydrocarbons (PAHs) and eleven nitropolycyclic aromatic hydrocarbons (NPAHs) were determined by HPLC with fluorescence and chemiluminescence detections, respectively. Annual concentrations of PAHs and NPAHs were in the order, China>Russia≫Korea=Japan, with seasonal change (winter>summer). During the observation period, concentrations of PAHs and NPAHs in Japanese cities significantly decreased but the increases in the PAH concentration were observed in Chinese and Russian cities. Concentrations of PAHs and NPAHs were higher in the Northern China than those in the Southern China. At the Noto peninsula, which is in the main path of winter northwest winds and a year-round jet stream that blow from the Asian continent to Japan, the concentrations were high in winter and low in summer every year. A cluster analysis and back trajectory analysis indicated that PAHs and NPAHs were long-range transported from Northeastern China, where coal burning systems such as coal-heating boilers are considered to be the major contributors of PAHs and NPAHs. A dramatic change in atmospheric concentrations of PAHs and NPAHs in East Asia suggests the rapid and large change of PM2.5 pollution in East Asia. Considering the adverse health effects of PM2.5, continuous monitoring of atmospheric PAHs and NPAHs is necessary in this area.

  1. Linkage of Aromatic Ring Structures in Saturates, Aromatics, Resins and Asphaltenes Fractions of Vacuum Residues Determined by Collision-Induced Dissociation Technology

    Institute of Scientific and Technical Information of China (English)

    Wang Wei; Liu Yingrong; Liu Zelong; Hou Huandi; Tian Songbai

    2016-01-01

    The linkage of aromatic ring structures in vacuum residues was important for the reifning process. The Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) combined with collision-induced dissociation (CID) is a powerful method to characterize the molecular structure of petroleum fractions. In this work, model compounds with differ-ent aromatic ring structures were measured by CID FT-ICR MS. The cracking of the parent ions and the generated fragment ions were able to distinguish different linkage of the model compounds. Then, vacuum residues were separated into saturates, aromat-ics, resins and asphaltenes fractions (SARA), and each fraction was characterized by CID technology. According to the experi-mental results, the aromatic rings in saturates and aromatics fractions were mainly of the island-type structures, while the aromatic rings in resins and asphaltenes fractions had a signiifcant amount of archipelago-type structures.

  2. Review: Biological fertilization and its effect on medicinal and aromatic plants

    Directory of Open Access Journals (Sweden)

    KHALID ALI KHALID

    2012-11-01

    Full Text Available Khalid KA. 2012. Review: Biological fertilization and its effect on medicinal and aromatic plants. Nusantara Bioscience 4: 124-133. The need of increase food production in the most of developing countries becomes an ultimate goal to meet the dramatic expansion of their population. However, this is also associated many cases with a reduction of the areas of arable land which leaves no opinion for farmers but to increase the yield per unit area through the use of improved the crop varieties, irrigation and fertilization. The major problem facing the farmer is that he cannot afford the cost of these goods, particularly that of chemical fertilizers. Moreover, in countries where fertilizer production relies on imported raw materials, the costs are even higher for farmer and for the country. Besides this, chemical fertilizers production and utilization are considered as air, soil and water polluting operations. The utilization of bio-fertilizers is considered today by many scientists as a promising alternative, particularly for developing countries. Bio-fertilization is generally based on altering the rhizosphere flora, by seed or soil inoculation with certain organisms, capable of inducing beneficial effects on a compatible host. Bio-fertilizers mainly comprise nitrogen fixes (Rhizobium, Azotobacter, Azospirellum, Azolla or blue green algae, phosphate dissolvers or vesicular-arbuscular mycorrhizas and silicate bacteria. These organisms may affect their host plant by one or more mechanisms such as nitrogen fixation, production of growth promoting substances or organic acids, enhancing nutrient uptake or protection against plant pathogens. Growth characters, yield, essential oil and its constituents, fixed oil, carbohydrates, soluble sugars and nutrients contents of medicinal and aromatic plants were significantly affected by adding the biological fertilizers compared with recommended chemical fertilizers.

  3. Novel aromatic ring-hydroxylating dioxygenase genes from coastal marine sediments of Patagonia

    Directory of Open Access Journals (Sweden)

    Ferrero Marcela A

    2008-03-01

    Full Text Available Abstract Background Polycyclic aromatic hydrocarbons (PAHs, widespread pollutants in the marine environment, can produce adverse effects in marine organisms and can be transferred to humans through seafood. Our knowledge of PAH-degrading bacterial populations in the marine environment is still very limited, and mainly originates from studies of cultured bacteria. In this work, genes coding catabolic enzymes from PAH-biodegradation pathways were characterized in coastal sediments of Patagonia with different levels of PAH contamination. Results Genes encoding for the catalytic alpha subunit of aromatic ring-hydroxylating dioxygenases (ARHDs were amplified from intertidal sediment samples using two different primer sets. Products were cloned and screened by restriction fragment length polymorphism analysis. Clones representing each restriction pattern were selected in each library for sequencing. A total of 500 clones were screened in 9 gene libraries, and 193 clones were sequenced. Libraries contained one to five different ARHD gene types, and this number was correlated with the number of PAHs found in the samples above the quantification limit (r = 0.834, p nahAc-like genes, phnAc-like genes as identified in Alcaligenes faecalis AFK2, and phnA1-like genes from marine PAH-degraders from the genus Cycloclasticus. Conclusion These results show the presence of hitherto unidentified ARHD genes in this sub-Antarctic marine environment exposed to anthropogenic contamination. This information can be used to study the geographical distribution and ecological significance of bacterial populations carrying these genes, and to design molecular assays to monitor the progress and effectiveness of remediation technologies.

  4. Calculations of proton chemical shifts in olefins and aromatics

    CERN Document Server

    Escrihuela, M C

    2000-01-01

    induced reagents on alpha,beta unsaturated ketones has also been investigated in order to deduce molecular structures and to obtain the assignment of the spectra of these molecules. A semi-empirical calculation of the partial atomic charges in organic compounds based on molecular dipole moments (CHARGE3) was developed into a model capable of predicting proton chemical shifts in a wide variety of organic compounds to a reasonable degree of accuracy. The model has been modified to include condensed aromatic hydrocarbons and substituted benzenes, alkenes, halo-monosubstituted benzenes and halo-alkenes. Within the aromatic compounds the influence of the pi electron densities and the ring current have been investigated, along with the alpha, beta and gamma effects. The model gives the first accurate calculation of the proton chemical shifts of condensed aromatic compounds and the proton substituent chemical shifts (SCS) in the benzene ring. For the data set of 55 proton chemical shifts spanning 3 ppm the rms error...

  5. The Nature of Intermolecular Interactions Between Aromatic Amino Acid Residues

    Energy Technology Data Exchange (ETDEWEB)

    Gervasio, Francesco; Chelli, Riccardo; Procacci, Piero; Schettino, Vincenzo

    2002-05-01

    The nature of intermolecular interactions between aromatic amino acid residues has been investigated by a combination of molecular dynamics and ab initio methods. The potential energy surface of various interacting pairs, including tryptophan, phenilalanine, and tyrosine, was scanned for determining all the relevant local minima by a combined molecular dynamics and conjugate gradient methodology with the AMBER force field. For each of these minima, single-point correlated ab initio calculations of the binding energy were performed. The agreement between empirical force field and ab initio binding energies of the minimum energy structures is excellent. Aromatic-aromatic interactions can be rationalized on the basis of electrostatic and van der Waals interactions, whereas charge transfer or polarization phenomena are small for all intermolecular complexes and, particularly, for stacked structures.

  6. Does oligomerization in fused thiophene affect reactivity and aromaticity?

    Indian Academy of Sciences (India)

    Siddhartha Kr Purkayastha; Pradip Kr Bhattacharyya

    2016-02-01

    Reactivity and aromaticity of a few fused thiophene oligomers and their conformers are discussed in the light of density functional theory (DFT) and conceptual density functional theory. Reactivity parameters, such as hardness () and electrophilicity (), chemical potential () and energy of the HOMO (highest occupied molecular orbital) have been studied. Oligomerization raises the HOMO of the species, which in turn increases the reactivity of the oligomers. The absorption spectra of the species are analysed using TDDFT (time dependent density functional theory). The absorption peaks show red shift with increasing size of the oligomers. Aromaticity of the species is gauged by nucleus independent chemical shift (NICS). The out-of-plane component, (NICSzz) values advocate higher aromatic character at longer distance whereas, NICS supports the reverse.

  7. Theoretical Estimate of Hydride Affinities of Aromatic Carbonyl Compounds

    Institute of Scientific and Technical Information of China (English)

    AI Teng; ZHU Xiao-Qing; CHENG Jin-Pei

    2003-01-01

    @@ Aromatic carbonyl compounds are one type of the most important organic compounds, and the reductions ofthem by hydride agents such as LiAlH4 or NaBH4 are widely used in organic synthesis. The reactivity of carbonyl compounds generally increases in the following order: ketone < aldehyde, and amide < acid < ester < acid halide, which could be related to their hydride affinities (HA). In the previous paper, Robert[1] calculated the absolute HAof a series of small non-aromatic carbonyl compounds. In this paper, we use DFT method at B3LYP/6-311 + + G (2d, 2p)∥B3LYP/6-31 + G* level to estimate hydride affinities of five groups of aromatic carbonyl compounds. The detailed results are listed in Table 1.

  8. Role in Cheese Flavour Formation of Heterofermentative Lactic Acid Bacteria from Mesophilic Starter Cultures

    DEFF Research Database (Denmark)

    Pedersen, Thomas Bæk

    Undefined mesophilic cheese starters are complex ecosystems that contain both homofermentative and heterofermentative lactic acid bacteria, with the Lactococcus genera representing the former and Lceuonostoc and sometimes Lactobacillus the latter. These starters originate from old butter starters...... aminopeptidase activity compared to Lactobacillus danicus and especially Le. mesenteroides subsp. cremoris had a low and narrow activity. Aminotransferase activity was high on aromatic amino acids for Lb. danicus, and the Leuconostoc species had an activity similar to Lb. danicus only after growth in CBM...... with plant isolates, the ability to ferment citrate and lacked several genes involved in the fermentation of complex carbohydrates. The presented research in this thesis has gained insight in to the role of heterofermentative lactic acid bacteria in cheese flavour formation. The traditional DL...

  9. Classification of Malaysia aromatic rice using multivariate statistical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, A. H.; Adom, A. H.; Shakaff, A. Y. Md; Masnan, M. J.; Zakaria, A.; Rahim, N. A. [School of Mechatronic Engineering, Universiti Malaysia Perlis, Kampus Pauh Putra, 02600 Arau, Perlis (Malaysia); Omar, O. [Malaysian Agriculture Research and Development Institute (MARDI), Persiaran MARDI-UPM, 43400 Serdang, Selangor (Malaysia)

    2015-05-15

    Aromatic rice (Oryza sativa L.) is considered as the best quality premium rice. The varieties are preferred by consumers because of its preference criteria such as shape, colour, distinctive aroma and flavour. The price of aromatic rice is higher than ordinary rice due to its special needed growth condition for instance specific climate and soil. Presently, the aromatic rice quality is identified by using its key elements and isotopic variables. The rice can also be classified via Gas Chromatography Mass Spectrometry (GC-MS) or human sensory panels. However, the uses of human sensory panels have significant drawbacks such as lengthy training time, and prone to fatigue as the number of sample increased and inconsistent. The GC–MS analysis techniques on the other hand, require detailed procedures, lengthy analysis and quite costly. This paper presents the application of in-house developed Electronic Nose (e-nose) to classify new aromatic rice varieties. The e-nose is used to classify the variety of aromatic rice based on the samples odour. The samples were taken from the variety of rice. The instrument utilizes multivariate statistical data analysis, including Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) and K-Nearest Neighbours (KNN) to classify the unknown rice samples. The Leave-One-Out (LOO) validation approach is applied to evaluate the ability of KNN to perform recognition and classification of the unspecified samples. The visual observation of the PCA and LDA plots of the rice proves that the instrument was able to separate the samples into different clusters accordingly. The results of LDA and KNN with low misclassification error support the above findings and we may conclude that the e-nose is successfully applied to the classification of the aromatic rice varieties.

  10. Classification of Malaysia aromatic rice using multivariate statistical analysis

    Science.gov (United States)

    Abdullah, A. H.; Adom, A. H.; Shakaff, A. Y. Md; Masnan, M. J.; Zakaria, A.; Rahim, N. A.; Omar, O.

    2015-05-01

    Aromatic rice (Oryza sativa L.) is considered as the best quality premium rice. The varieties are preferred by consumers because of its preference criteria such as shape, colour, distinctive aroma and flavour. The price of aromatic rice is higher than ordinary rice due to its special needed growth condition for instance specific climate and soil. Presently, the aromatic rice quality is identified by using its key elements and isotopic variables. The rice can also be classified via Gas Chromatography Mass Spectrometry (GC-MS) or human sensory panels. However, the uses of human sensory panels have significant drawbacks such as lengthy training time, and prone to fatigue as the number of sample increased and inconsistent. The GC-MS analysis techniques on the other hand, require detailed procedures, lengthy analysis and quite costly. This paper presents the application of in-house developed Electronic Nose (e-nose) to classify new aromatic rice varieties. The e-nose is used to classify the variety of aromatic rice based on the samples odour. The samples were taken from the variety of rice. The instrument utilizes multivariate statistical data analysis, including Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) and K-Nearest Neighbours (KNN) to classify the unknown rice samples. The Leave-One-Out (LOO) validation approach is applied to evaluate the ability of KNN to perform recognition and classification of the unspecified samples. The visual observation of the PCA and LDA plots of the rice proves that the instrument was able to separate the samples into different clusters accordingly. The results of LDA and KNN with low misclassification error support the above findings and we may conclude that the e-nose is successfully applied to the classification of the aromatic rice varieties.

  11. 南极石油烃降解嗜冷菌的筛选及其降解特性的研究%Antarctic Psychrophile Bacteria Screening for Oil Degradation and Their Degrading Characteristics

    Institute of Scientific and Technical Information of China (English)

    郑洲; 金青; 缪锦来; 刘芳明

    2008-01-01

    从 385 株南极海洋细菌中筛选出 2 株石油烃降解菌,并对其降解特性进行了初步研究.以柴油为唯一碳源进行降解实验的结果表明,南极嗜冷菌 NJ276 和 NJ341 在 5 °C、20 d 内对柴油的降解率分别达到 23.47 % 和32.15 %,在 15 °C、20 d 内降解率分别达到 43.95 % 和 62.47 %,其降解能力随着培养温度的升高而显著增强;石油烃降解残油组分的GC~MS分析表明,柴油经过 NJ276 降解后的残油组分中能检测到 C15~C21 七种烷烃,柴油经过 NJ341 降解后的残油组分只能检测到少量 C16,C17 和 C18 三种烷烃.对它们进行 16S rDNA 基因序列的同源性和系统发育分析表明,菌株 NJ276 属于假交替单胞菌属( Pseudoalteromonas),NJ341 属于科尔韦尔氏属(Colwellia).%Two hydrocarbon degrading bacteria NJ276 and NJ341 were screened from 385 Antarctic marine bacteria and their degrading characteristics were studied.Diesel oil as sole carbon source was used in this study.The results showed that the oil degradation rates of Antarctic psychrophile bacteria NJ276 and NJ341 were 23.47 % and 32.15 %,respectively,after 20 days culturation at 5 °C,and the rates were 43.95 % and 62.47 % respectively after 20 days culturation at 15 °C.The oil degradation abilities were enhanced remarkably with the increasing culture temperature.GC-MSs indicated the residual oil contained C15-C21 7 alkyls after degradation by NJ276,and C16,C17 and C18 3 alkyls after degradation by NJ341.The 16S rDNA gene sequences homology and phylogenetic analysis of the two Antarctic psychrophile bacteria showed that NJ276 belonged to the described genus Pseudoalteromonas and NJ341 belonged to the genus Colwellia.

  12. Deodorant bacteria; Des bacteries desodorisantes

    Energy Technology Data Exchange (ETDEWEB)

    Fanlo, J.L. [Ecole Nationale Superieure des Mines, 30 - Ales (France)

    1998-02-01

    Purifying bacteria: if this concept is not new, its application to gases cleansing has only been developed recently. This method allows to eliminate the volatile organic compounds and the gaseous effluents odors which come from industrial sites. Three bioreactors types exist at the present time. Their principles are explained. (O.M.) 6 refs.

  13. Functional genomics of intracellular bacteria.

    Science.gov (United States)

    de Barsy, Marie; Greub, Gilbert

    2013-07-01

    During the genomic era, a large amount of whole-genome sequences accumulated, which identified many hypothetical proteins of unknown function. Rapidly, functional genomics, which is the research domain that assign a function to a given gene product, has thus been developed. Functional genomics of intracellular pathogenic bacteria exhibit specific peculiarities due to the fastidious growth of most of these intracellular micro-organisms, due to the close interaction with the host cell, due to the risk of contamination of experiments with host cell proteins and, for some strict intracellular bacteria such as Chlamydia, due to the absence of simple genetic system to manipulate the bacterial genome. To identify virulence factors of intracellular pathogenic bacteria, functional genomics often rely on bioinformatic analyses compared with model organisms such as Escherichia coli and Bacillus subtilis. The use of heterologous expression is another common approach. Given the intracellular lifestyle and the many effectors that are used by the intracellular bacteria to corrupt host cell functions, functional genomics is also often targeting the identification of new effectors such as those of the T4SS of Brucella and Legionella.

  14. Synthetic Biology in Streptomyces Bacteria

    NARCIS (Netherlands)

    Medema, Marnix H.; Breitling, Rainer; Takano, Eriko

    2011-01-01

    Actinomycete bacteria of the genus Streptomyces are major producers of bioactive compounds for the biotechnology industry. They are the source of most clinically used antibiotics, as well as of several widely used drugs against common diseases, including cancer . Genome sequencing has revealed that

  15. SYNTHETIC BIOLOGY IN STREPTOMYCES BACTERIA

    NARCIS (Netherlands)

    Medema, Marnix H.; Breitling, Rainer; Takano, Eriko; Voigt, C

    2011-01-01

    Actinomycete bacteria of the genus Streptomyces are major producers of bioactive compounds for the biotechnology industry. They are the source of most clinically used antibiotics, as well as of several widely used drugs against common diseases, including cancer. Genome sequencing has revealed that t

  16. Manipulating Genetic Material in Bacteria

    Science.gov (United States)

    1998-01-01

    Lisa Crawford, a graduate research assistant from the University of Toledo, works with Laurel Karr of Marshall Space Flight Center (MSFC) in the molecular biology laboratory. They are donducting genetic manipulation of bacteria and yeast for the production of large amount of desired protein. Photo credit: NASA/Marshall Space Flight Center (MSFC)

  17. Programmed survival of soil bacteria

    DEFF Research Database (Denmark)

    Jensen, Lars Bogø; Molin, Søren; Sternberg, Claus

    Biological containment systems have been developed for Pseudomonas putida and related soil bacteria. The systems are based on combinations of lethal genes and regulated gene expression. Two types of killing function have been employed: 1) A membrane protein interfering with the membrane potential...

  18. ENDOSPORES OF THERMOPHILIC FERMENTATIVE BACTERIA

    DEFF Research Database (Denmark)

    Volpi, Marta

    2016-01-01

    solely based on endospores of sulphate-reducing bacteria (SRB), which presumably constitute only a small fraction of the total thermophilic endospore community reaching cold environments. My PhD project developed an experimental framework for using thermophilic fermentative endospores (TFEs) to trace...

  19. Engineering robust lactic acid bacteria

    NARCIS (Netherlands)

    Bron, P.A.; Bokhorst-van de Veen, van H.; Wels, M.; Kleerebezem, M.

    2011-01-01

    For centuries, lactic acid bacteria (LAB) have been industrially exploited as starter cultures in the fermentation of foods and feeds for their spoilage-preventing and flavor-enhancing characteristics. More recently, the health-promoting effects of LAB on the consumer have been widely acknowledged,

  20. DAR Assisted Layer-by-Layer Assembly of Aromatic Compounds

    Institute of Scientific and Technical Information of China (English)

    姜思光; 陈晓东; 张莉; 刘鸣华

    2003-01-01

    A facile DAR (diphenylamine-4-diazonium-formaldehyde resin)assisted layer-by-layer (LbL) assembly of uitrathin organic film of aromatic compounds has been investigated. The muitilayer of pyrene or anthracene was fabricated through simple dipping of the glass slide into the mixed solution of DAR with the target compounds. In this method, DAR acted as an assistant compound to help the assembling of the aromatic compounds. Such a convenient deposition method not only reserves the advantages of the traditional LbL technique but also simplifies the technique and extends the effectiveness of LbL technique to small molecules without any charge.

  1. Exposure of iron foundry workers to polycyclic aromatic hydrocarbons

    DEFF Research Database (Denmark)

    Omland, Øyvind; Sherson, D; Hansen, Åse Marie

    1994-01-01

    Exposure to polycyclic aromatic hydrocarbons (PAHs) in foundry workers has been evaluated by determination of benzo(a)pyrene-serum albumin adducts and urinary 1-hydroxypyrene. Benzo(a)pyrene binding to albumin and 1-hydroxypyrene were quantitatively measured by enzyme linked immunosorbent assay...... than in smoking and non-smoking controls (0 (0-0.022) and 0 (0-0.010) mumol/mol creatinine). Dose-response relations between total PAH, pyrene, carcinogenic PAHs, and 1-hydroxypyrene for smokers, and polycyclic aromatic hydrocarbons adsorbed to dust for non-smokers are suggested. Exposure to PAHs...

  2. Polycyclic aromatic hydrocarbons in air samples of meat smokehouses

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Olsen, I L; Poulsen, O M

    1992-01-01

    In a screening programme nine Danish meat smokehouses were randomly selected for measurements on concentration of airborne polycyclic aromatic hydrocarbons (PAH). A total of 23 stationary air samples were collected during the entire working period of the kiln either above the kiln doors or approx......In a screening programme nine Danish meat smokehouses were randomly selected for measurements on concentration of airborne polycyclic aromatic hydrocarbons (PAH). A total of 23 stationary air samples were collected during the entire working period of the kiln either above the kiln doors...

  3. Development and Application of Heat-integrated Aromatics Fractionation Process

    Institute of Scientific and Technical Information of China (English)

    Yang Weisheng; Kong Dejin; Tan Yongzhong

    2009-01-01

    The PRO/Ⅱ process simulation software was applied to carry out simulated calculation of the aromatics frac-tionation unit and the heat integrated rectification process was proposed for the aromatics fractionation section of the 1.0 Mt/a toluene disproportionation unit at the Zhenhai Refining and Chemical Company. The optimized operating parameters were obtained through the energy utilization analysis, process simulation, heat exchanger calculations and comparisons of utility consumption. The operation of commercialized unit has revealed that the design parameters of each rectification column were consistent with the operation results, and the utility consumption was about 47% lower than the waditional heat integrated process.

  4. Aroma transition from rosemary leaves during aromatization of olive oil

    Directory of Open Access Journals (Sweden)

    Mustafa Yılmazer

    2016-04-01

    Full Text Available The aroma profile of aromatized olive oil was determined in this study. The primary objective was to investigate the transition of major aroma compounds from rosemary and olive fruit during the kneading step of olive oil production by response surface methodology. For this purpose, temperature, time, and amount of rosemary leaves were determined as independent variables. The results indicated that temperature and time did not affect the transition of target compounds, but rosemary leaves addition had a strong influence on transition, especially for characteristic aroma compounds of this herb. Adequacies of developed models were found to be high enough to predict each aromatic component of interest.

  5. Recent Studies on the Aromaticity and Antiaromaticity of Planar Cyclooctatetraene

    Directory of Open Access Journals (Sweden)

    Masahiko Iyoda

    2010-02-01

    Full Text Available Cyclooctatetraene (COT, the first 4nπ-electron system to be studied, adopts an inherently nonplanar tub-shaped geometry of D2d symmetry with alternating single and double bonds, and hence behaves as a nonaromatic polyene rather than an antiaromatic compound. Recently, however, considerable 8π-antiaromatic paratropicity has been shown to be generated in planar COT rings even with the bond alternated D4h structure. In this review, we highlight recent theoretical and experimental studies on the antiaromaticity of hypothetical and actual planar COT. In addition, theoretically predicted triplet aromaticity and stacked aromaticity of planar COT are also briefly described.

  6. Synthesis and Characterization of Aliphatic-Aromatic Hyperbranched Polyesters

    Institute of Scientific and Technical Information of China (English)

    唐黎明; 张晓龙; 邱藤; 刘德山

    2002-01-01

    Hyperbranched polymers possess special architectures and have potential applications in various areas. In this study, two AB2 monomers, dipropyl 5-(hydroxyethoxy) isophthalate (I) and 5-hydroxyethoxyisophthaic acid (II), were prepared. By bulk polycondensation of each monomer, two aliphatic-aromatic hyperbranched polyesters were prepared and characterized by 1H-nuclear magnetic resonance (1H-NMR), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), and scanning electron microscopy (SEM). Compared with all-aromatic hyperbranched polyesters, the prepared polymers showed lower glass transition temperatures in connection with the moderate decrease in their decomposition temperatures.

  7. Low toxicity aromatic diamine curing agents for adhesives

    Energy Technology Data Exchange (ETDEWEB)

    Dorsey, G.F.

    1993-08-24

    Increasing severity of regulations for handling of hazardous materials has led to formulation of adhesives with considerably lowered toxicities for use at the Oak Ridge Y-12 Plant. Fundamental was the development of Asilamine aromatic diamines, a family of liquid aromatic diamines useful as substitutes for methylenedianiline (MDA), a widely used adhesives curing agent. The use of Asilamine has allowed us to continue operations without dealing with expensive measures for regulation of MDA as a carcinogen promulgated by the Occupational Safety and Health Administration (OSHA).

  8. New aromatic polyamides and polyimides having an adamantine bulky group

    OpenAIRE

    2015-01-01

    Producción Científica This paper reports the synthesis and characterization of a new rigid diamine monomer, having a spiro carbon moiety and an adamantane bulky group in its structure; namely spiro-(adamantane-2,9′(2',7'-diamino)-fluorene) (SADAF). After its synthesis, using a straightforward methodology, a novel family of aromatic polyimides (PIs) and polyamides (PAs) has been attained by reaction of SADAF with three aromatic dianhydrides and two diacid chlorides, respectively. Two of the...

  9. Identification of bacteria utilizing biphenyl, benzoate, and naphthalene in long-term contaminated soil.

    Directory of Open Access Journals (Sweden)

    Ondrej Uhlik

    Full Text Available Bacteria were identified associated with biodegradation of aromatic pollutants biphenyl, benzoate, and naphthalene in a long-term polychlorinated biphenyl- and polyaromatic hydrocarbon-contaminated soil. In order to avoid biases of culture-based approaches, stable isotope probing was applied in combination with sequence analysis of 16 S rRNA gene pyrotags amplified from (13C-enriched DNA fractions. Special attention was paid to pyrosequencing data analysis in order to eliminate the errors caused by either generation of amplicons (random errors caused by DNA polymerase, formation of chimeric sequences or sequencing itself. Therefore, sample DNA was amplified, sequenced, and analyzed along with the DNA of a mock community constructed out of 8 bacterial strains. This warranted that appropriate tools and parameters were chosen for sequence data processing. (13C-labeled metagenomes isolated after the incubation of soil samples with all three studied aromatics were largely dominated by Proteobacteria, namely sequences clustering with the genera Rhodanobacter Burkholderia, Pandoraea, Dyella as well as some Rudaea- and Skermanella-related ones. Pseudomonads were mostly labeled by (13C from naphthalene and benzoate. The results of this study show that many biphenyl/benzoate-assimilating bacteria derive carbon also from naphthalene, pointing out broader biodegradation abilities of some soil microbiota. The results also demonstrate that, in addition to traditionally isolated genera of degradative bacteria, yet-to-be cultured bacteria are important players in bioremediation. Overall, the study contributes to our understanding of biodegradation processes in contaminated soil. At the same time our results show the importance of sequencing and analyzing a mock community in order to more correctly process and analyze sequence data.

  10. Fuzzy species among recombinogenic bacteria

    Directory of Open Access Journals (Sweden)

    Fraser Christophe

    2005-03-01

    Full Text Available Abstract Background It is a matter of ongoing debate whether a universal species concept is possible for bacteria. Indeed, it is not clear whether closely related isolates of bacteria typically form discrete genotypic clusters that can be assigned as species. The most challenging test of whether species can be clearly delineated is provided by analysis of large populations of closely-related, highly recombinogenic, bacteria that colonise the same body site. We have used concatenated sequences of seven house-keeping loci from 770 strains of 11 named Neisseria species, and phylogenetic trees, to investigate whether genotypic clusters can be resolved among these recombinogenic bacteria and, if so, the extent to which they correspond to named species. Results Alleles at individual loci were widely distributed among the named species but this distorting effect of recombination was largely buffered by using concatenated sequences, which resolved clusters corresponding to the three species most numerous in the sample, N. meningitidis, N. lactamica and N. gonorrhoeae. A few isolates arose from the branch that separated N. meningitidis from N. lactamica leading us to describe these species as 'fuzzy'. Conclusion A multilocus approach using large samples of closely related isolates delineates species even in the highly recombinogenic human Neisseria where individual loci are inadequate for the task. This approach should be applied by taxonomists to large samples of other groups of closely-related bacteria, and especially to those where species delineation has historically been difficult, to determine whether genotypic clusters can be delineated, and to guide the definition of species.

  11. Phenylalanyl-Glycyl-Phenylalanine Tripeptide: A Model System for Aromatic-Aromatic Side Chain Interactions in Proteins

    Energy Technology Data Exchange (ETDEWEB)

    Valdes, Haydee; Pluhackova, Kristyna; Hobza, Pavel

    2009-09-08

    The performance of a wide range of quantum chemical calculations for the ab initio study of realistic model systems of aromatic-aromatic side chain interactions in proteins (in particular those π-π interactions occurring between adjacent residues along the protein sequence) is here assessed on the phenylalanyl-glycyl-phenylalanine (FGF) tripeptide. Energies and geometries obtained at different levels of theory are compared with CCSD(T)/CBS benchmark energies and RI-MP2/cc-pVTZ benchmark geometries, respectively. Consequently, a protocol of calculation alternative to the very expensive CCSD(T)/CBS is proposed. In addition to this, the preferred orientation of the Phe aromatic side chains is discussed and compared with previous results on the topic.

  12. Continuous Flow Nucleophilic Aromatic Substitution with Dimethylamine Generated in Situ by Decomposition of DMF

    DEFF Research Database (Denmark)

    Petersen, Trine P; Larsen, Anders Foller; Ritzén, Andreas;

    2013-01-01

    A safe, practical, and scalable continuous flow protocol for the in situ generation of dimethylamine from DMF followed by nucleophilic aromatic substitution of a broad range of aromatic and heteroaromatic halides is reported....

  13. Study on Aromatization of C6 Aliphatic Hydrocarbons on ZRP Zeolite Catalyst

    Institute of Scientific and Technical Information of China (English)

    Wang Yongjun; Xie Chaogang

    2004-01-01

    The performance of ZRP zeolite catalysts for aromatization of C6 aliphatic hydrocarbons was investigated in a pulsed microreactor. The influence of metal modified ZRP zeolites on aromatization reaction was also studied, coupled with comparison of aromatization tendencies of olefins, paraffins and paraffins with different degrees of chain branching. Test results had shown that the lower the silicon/aluminum ratio in the ZRP zeolite, the higher the aromatization reactivity of aliphatic hydrocarbons. Modification of ZRP zeolite by zinc and its zinc content had apparent impact on the yield and distribution of aromatics. The aromatization tendency of olefins was apparently better than paraffins, while the aromatization tendency of monomethyl paraffins was better than that of straight-chain paraffins with the exception of dimethyl paraffins, which had worse aromatization tendency because of their steric hindrance.

  14. Adsorption of polar, nonpolar, and substituted aromatics to colloidal graphene oxide nanoparticles

    NARCIS (Netherlands)

    Wang, Fang; Haftka, Joris J H; Sinnige, Theo L.; Hermens, Joop L M; Chen, Wei

    2014-01-01

    We conducted batch adsorption experiments to understand the adsorptive properties of colloidal graphene oxide nanoparticles (GONPs) for a range of environmentally relevant aromatics and substituted aromatics, including model nonpolar compounds (pyrene, phenanthrene, naphthalene, and 1,3-dichlorobenz

  15. Physicochemical Mechanisms of Synergistic Biological Action of Combinations of Aromatic Heterocyclic Compounds

    Directory of Open Access Journals (Sweden)

    Maxim P. Evstigneev

    2013-01-01

    Full Text Available The mechanisms of synergistic biological effects observed in the simultaneous use of aromatic heterocyclic compounds in combination are reviewed, and the specific biological role of heteroassociation of aromatic molecules is discussed.

  16. Biotransformation and Biodegradation of N-Substituted Aromatics in Methanogenic Granular Sludge.

    NARCIS (Netherlands)

    Razo Flores, E.

    1997-01-01

    N-substituted aromatic compounds are environmental contaminants associated with the production and use of dyes, explosives, pesticides and pharmaceuticals among others. Nitro- and azo-substituted aromatic compounds with strong electron withdrawing groups are poorly biodegradable in aerobic treatment

  17. AROMATIC AND HETEROCYCLIC DINITRILES AND THEIR POLYMERS XIV. STUDY ON THE CATALYSTS OF THE POLYMERIZATION OF AROMATIC NITRILES

    Institute of Scientific and Technical Information of China (English)

    SUN Luying; HUANG Zhitang

    1989-01-01

    Various catalysts for the polymerization ot aromatic nitriles were investigated. It was found that Lewis acid - metal is a preferable catalyst system for the polymerization of aromatic nitriles,and the polymerization rate is about 10 times faster than Lewis acid alone. The polymerization rate of benzonitrile catalyzed by Lewis acid and different metals was measured, and the activity of metals was in the following decreasing order ,magnesium, zinc, sodium, calcium. Furthermore, the polymerization of benzonitrile catalyzed by different Lewis acid and zinc was also investigated.

  18. Ambient cure polyimide foams prepared from aromatic polyisocyanates, aromatic polycarboxylic compounds, furfuryl alcohol, and a strong inorganic acid

    Science.gov (United States)

    Sawko, Paul M. (Inventor); Riccitiello, Salvatore R. (Inventor); Hamermesh, Charles L. (Inventor)

    1980-01-01

    Flame and temperature resistant polyimide foams are prepared by the reaction of an aromatic dianhydride, e.g., pyromellitic dianhydride, with an aromatic polyisocyanate, e.g., polymethylene polyphenylisocyanate (PAPI) in the presence of an inorganic acid and a lower molecular weight alcohol, e.g., dilute sulfuric acid or phosphoric acid and furfuryl alcohol. The exothermic reaction between the acid and the alcohol provides the heat necessary for the other reactants to polymerize without the application of any external heat. Such mixtures, therefore, are ideally suited for in situ foam formation, especially where the application of heat is not practical or possible.

  19. Benzylation of Aromatic Compounds with Benzyl Chloride Catalyzed by Nafion/SiO2 Nanocomposite Catalyst

    Institute of Scientific and Technical Information of China (English)

    Kun Guo YANG; Rui Mao HUA; Hai WANG; Bo Qing XU1

    2005-01-01

    In the presence of Nafion/SiO2 nanocomposite catalyst, the benzylation of aromatic compounds with benzyl chloride proceeded to afford diphenylmethane derivatives in high yields.The catalyst showed high catalytic activity not only for electron-rich aromatic compounds, but also for electron-poor aromatic compounds. Under identical conditions, the self-benzylation of benzyl chloride, and dibenzylation and/or multi-benzylation of aromatic compounds were negligible.

  20. [Degradation and biosynthesis of L-phenylalanine by chloridazon-degrading bacteria].

    Science.gov (United States)

    Buck, R; Eberspächer, J; Lingens, F

    1979-07-01

    Incubating chloridazon-degrading bacteria with L-phenylalanine leads to the accumulation of L-2,3-dihydroxyphenylalanine, o-tyrosine and m-tyrosine in the medium. Incubating the bacteria with N-acetyl-L-phenylalanine leads to N-acetyl-(2,3-dihydroxyphenyl)alanine. Using phenylacetic acid as substrate leads to the accumulation of malonic acid. The products are isolated by gel chromatography and high performance liquid chromatography. 2,3-Dihydroxy-L-phenylalanine is attacked by a catechol 2,3-dioxygenase in the presence of Fe2. An unstable yellow compound is formed in this reaction. This meta-cleavage-product is again cleaved by a hydrolase, leading to aspartic acid and 4-hydroxy-2-oxovaleric acid. Both products were isolated fromthe reaction buffer by amino acid analysis and high performance liquid chromatography. The dioxygenase and hydrolase were partially purified and characterized. A new degradation pathway for phenylalanine is discussed and compared with known pathways. The enzymes chorismate mutase, prephenate dehydratase and prephenate dehydrogenase are characterized and inhibition as well as repression are investigated. Only prephenate dehydrogenase is inhibited by phenylalanine, tyrosine and tryptophane. Chorismate mutase is repressed by phenylalanine, prephenate dehydrogenase by phenylalanine and tyrosine. Prephenate dehydratase is not repressed by aromatic amino acids. Regulation of aromatic amino acid biosynthesis in connection with phenylalanine degradation is discussed.

  1. Burning Incense and Aromatic Plants for Auspicious Smoke in Lhasa

    Institute of Scientific and Technical Information of China (English)

    ZHANGZONGXIAN

    2004-01-01

    People of the Tibetan ethnic group follow certain rituals that are remnants of the primitive religion that existed in the region many centuries ago,including buming incense and aromatic plants to create auspicious smoke, as well as blood rituals and the sorcerer's dance.

  2. Interactions of polyhalogeneted aromatic hydrocarbons with thyroid hormone metabolism.

    NARCIS (Netherlands)

    Schuur, A.G.

    1998-01-01

    This thesis deals with the possible interactions of polyhalogenated aromatic hydrocarbons and/or their metabolites with thyroid hormone metabolism. This chapter summarizes firstly the effects of thyroid hormone on the induction of biotransformation enzymes by PHAHs. Secondly, the results on the inhi

  3. Polycyclic aromatic hydrocarbons (PAH) in Danish barbecued meat

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; Aaslyng, Margit Dall; Meinert, Lene

    2015-01-01

    Barbecuing is known to result in the formation of polycyclic aromatic hydrocarbons (PAHs). A validated method that employed pressurized liquid extraction (PLE), gel permeation chromatography (GPC) followed by solid phase extraction (SPE) on Silica and analytical determination by GC-MS was applied...

  4. Stereochemistry of bistricyclic aromatic enes and related polycyclic systems.

    Science.gov (United States)

    Biedermann, P Ulrich; Agranat, Israel

    2014-01-01

    Bistricyclic aromatic enes (BAEs) and related polycyclic systems are a class of molecular materials that display a rich variety of conformations, dynamic stereochemistry and switchable chirality, color, and spectroscopic properties. This is due to the a subtle interplay of the inherent preference for planarity of aromatic systems and the competing necessity of non-planarity due to intramolecular overcrowding in the fjord regions built into the general molecular structure of BAEs. The conformational, dynamic, and spectroscopic properties may be designed and fine-tuned, e.g., by variation of the bridging groups X and Y, the overcrowding in the fjord regions, extensions of the aromatic system, or other modifications of the general BAE structure, based on the fundamental understanding of the structure-property relationships (SPR). The present review provides an analysis of the conformational spaces and the dynamic stereochemistry of overcrowded bistricyclic aromatic enes applying fundamental symmetry considerations. The symmetry analysis presented here allows deeper insight into the conformations, chirality, and the mechanisms of the dynamic stereochemistry, and will be instrumental in future computational studies.

  5. Quantification of Aromaticity Based on Interaction Coordinates: A New Proposal.

    Science.gov (United States)

    Pandey, Sarvesh Kumar; Manogaran, Dhivya; Manogaran, Sadasivam; Schaefer, Henry F

    2016-05-12

    Attempts to establish degrees of aromaticity in molecules are legion. In the present study, we begin with a fictitious fragment arising from only those atoms contributing to the aromatic ring and having a force field projected from the original system. For example, in benzene, we adopt a fictitious C6 fragment with a force field projected from the full benzene force field. When one bond or angle is stretched and kept fixed, followed by a partial optimization for all other internal coordinates, structures change from their respective equilibria. These changes are the responses of all other internal coordinates for constraining the bond or angle by unit displacements and relaxing the forces on all other internal coordinates. The "interaction coordinate" derived from the redundant internal coordinate compliance constants measures how a bond (its electron density) responds for constrained optimization when another bond or angle is stretched by a specified unit (its electron density is perturbed by a finite amount). The sum of interaction coordinates (responses) of all bonded neighbors for all internal coordinates of the fictitious fragment is a measure of the strength of the σ and π electron interactions leading to aromatic stability. This sum, based on interaction coordinates, appears to be successful as an aromaticity index for a range of chemical systems. Since the concept involves analyzing a fragment rather than the whole molecule, this idea is more general and is likely to lead to new insights.

  6. Resonance and Aromaticity : An Ab Initio Valence Bond Approach

    NARCIS (Netherlands)

    Rashid, Zahid; van Lenthe, Joop H.; Havenith, Remco W. A.

    2012-01-01

    Resonance energy is one of the criteria to measure aromaticity. The effect of the use of different orbital models is investigated in the calculated resonance energies of cyclic conjugated hydrocarbons within the framework of the ab initio Valence Bond Self-Consistent Field (VBSCF) method. The VB wav

  7. Bioavailability of Polycyclic Aromatic Hydrocarbons in Soils and Sediments

    NARCIS (Netherlands)

    Cuypers, M.P.

    2001-01-01

    Polycyclic aromatic hydrocarbons (PAHs) constitute a group of priority pollutants which are of increasing environmental concern because of their adverse effects on humans, animals, and plants. Soils and sediments generally serve as a sink for PAHs, which leads to the accumulation of PAHs at contamin

  8. Environmental polycyclic aromatic hydrocarbons affect androgen receptor activation in vitro

    DEFF Research Database (Denmark)

    Vinggaard, Anne Marie; Hnida, Christina; Larsen, John Christian

    2000-01-01

    Nine structurally different polycyclic aromatic hydrocarbons (PAHs) were tested for their ability to either agonize or antagonize the human androgen receptor (hAR) in a sensitive reporter gene assay based on CHO cells transiently cotransfected with a hAR vector and an MMTV-LUC vector. Benz...

  9. Biotransformation of polycyclic aromatic hydrocarbons in marine polychaetes

    DEFF Research Database (Denmark)

    Jørgensen, Anne; Giessing, Anders; Rasmussen, Lene Juel

    2008-01-01

    Deposit-feeding polychaetes constitute the dominant macrofauna in marine environments that tend to be depositional centers for organic matter and contaminants. Polychaetes are known to accumulate polycyclic aromatic hydrocarbons (PAHs) from both particulate and dissolved phases but less is known...

  10. Reaction of benzoxasilocines with aromatic aldehydes: Synthesis of homopterocarpans

    Directory of Open Access Journals (Sweden)

    Rodríguez-García Ignacio

    2007-02-01

    Full Text Available Abstract Condensation of 2H-benzo[g][1,2]oxasilocines with aromatic aldehydes in the presence of boron trifluoride affords mixtures of cis/trans 2-phenyl-3-vinylchromans with moderate yields. These can be transformed into homopterocarpans, a synthetic group of substances homologous to the natural isoflavonoid pterocarpans.

  11. Aromaticity in Polyacene Analogues of Inorganic Ring Compounds

    CERN Document Server

    Chattaraj, P K; Chattaraj, Pratim Kumar; Roy, Debesh Ranjan

    2006-01-01

    The aromaticity in the polyacene analogues of several inorganic ring compounds (BN-acenes, CN-acenes, BO-acenes and Na6-acenes) is reported here for the first time. Conceptual density functional theory based reactivity descriptors and the nucleus independent chemical shift (NICS) values are used in this analysis.

  12. Integrated Environmental Quality Objectives for Polycyclic Aromatic Hydrocarbons (PAHs)

    NARCIS (Netherlands)

    Kalf DF; Crommentuijn GH; Posthumus R; Plassche EJ van de; ACT

    1995-01-01

    In the present report Maximum Permissible Concentrations (MPCs) are derived for 10 Polycyclic Aromatic Hydrocarbons (PAHs). For the aquatic environment MPCs are derived from the available experimental data. For 3 PAHs no experimental data are available. These MPCs are calculated using the QSAR-appro

  13. Iodine, a Mild Reagent for the Aromatization of Terpenoids.

    Science.gov (United States)

    Domingo, Victoriano; Prieto, Consuelo; Silva, Lucia; Rodilla, Jesús M L; Quílez del Moral, José F; Barrero, Alejandro F

    2016-04-22

    Efficient procedures based on the use of iodine for the aromatization of a series of terpenoids possessing diene and homoallylic or allylic alcohol functionalities are described. Different examples are reported as a proof-of-concept study. Furthermore, iodine also proved to mediate the dehydrogenation of testosterone.

  14. CONTROL OF AROMATIC WASTE AIR STREAMS BY SOIL BIOREACTORS

    Science.gov (United States)

    Three soils were examined for the ability to degrade hydrocarbon vapors of benzene, toluene, ethylbenzene, and o-xylene (BTEX). Each of these compounds are major aromatic constituents of gasolines. The soils examined were Rubicon Sand from Traverse City, Michigan, Durant Loam fro...

  15. The formation of polycyclic aromatic hydrocarbons in evolved circumstellar environments

    CERN Document Server

    Cherchneff, Isabelle

    2010-01-01

    The formation of Polycyclic Aromatic Hydrocarbons in the circumstellar outflows of evolved stars is reviewed, with an emphasis on carbon stars on the Asymptotic Giant Branch. Evidence for PAHs present in their winds is provided by meteoritic studies and recent observations of the Unidentified Infrared bands. We detail the chemical processes leading to the closure of the first aromatic ring as well as the growth mechanisms leading to amorphous carbon grains. Existing studies on PAH formation in evolved stellar envelopes are reviewed and new results for the modelling of the inner wind of the archetype carbon star IRC+10216 are presented. Benzene, C6H6, forms close to the star, as well as water, H2O, as a result of non-equilibrium chemistry induced by the periodic passage of shocks. The growth process of aromatic rings may thus resemble that active in sooting flames due to the presence of radicals like hydroxyl, OH. Finally, we discuss possible formation processes for PAHs and aromatic compounds in the hydrogen-...

  16. THE RATES OF POLYCYCLIC AROMATIC HYDROCARBON EMISSIONS FROM INCENSE BURNING

    Science.gov (United States)

    The paper presents the results of experiments performed to determine the amounts of gas- and particle-phase polycyclic aromatic hydrocarbons (PAHS) in incense smoke. Ten brands of incense, 3 of stick, 2 of joss stick, and one each of cone, smudge bundle, rope, powder, and rock, w...

  17. Polycyclic aromatic hydrocarbons in soils around Guanting Reservoir, Beijing, China

    NARCIS (Netherlands)

    Jiao, W.T.; Lu, Y.L.; Wang, T.Y.; Li, J.; Han, Jingyi; Wang, G.; Hu, W.Y.

    2009-01-01

    The concentrations of 16 polycyclic aromatic hydrocarbons ( 16PAHs) were measured by gas chromatography equipped with a mass spectrometry detector (GC-MS) in 56 topsoil samples around Guanting Reservior (GTR), which is an important water source for Beijing. Low to medium levels of PAH contamination

  18. Genomic and molecular mechanisms for efficient biodegradation of aromatic dye.

    Science.gov (United States)

    Sun, Su; Xie, Shangxian; Chen, Hu; Cheng, Yanbing; Shi, Yan; Qin, Xing; Dai, Susie Y; Zhang, Xiaoyu; Yuan, Joshua S

    2016-01-25

    Understanding the molecular mechanisms for aromatic compound degradation is crucial for the development of effective bioremediation strategies. We report the discovery of a novel phenomenon for improved degradation of Direct Red 5B azo dye by Irpex lacteus CD2 with lignin as a co-substrate. Transcriptomics analysis was performed to elucidate the molecular mechanisms of aromatic degradation in white rot fungus by comparing dye, lignin, and dye/lignin combined treatments. A full spectrum of lignin degradation peroxidases, oxidases, radical producing enzymes, and other relevant components were up-regulated under DR5B and lignin treatments. Lignin induced genes complemented the DR5B induced genes to provide essential enzymes and redox conditions for aromatic compound degradation. The transcriptomics analysis was further verified by manganese peroxidase (MnP) protein over-expression, as revealed by proteomics, dye decolorization assay by purified MnP and increased hydroxyl radical levels, as indicated by an iron reducing activity assay. Overall, the molecular and genomic mechanisms indicated that effective aromatic polymer degradation requires synergistic enzymes and radical-mediated oxidative reactions to form an effective network of chemical processes. This study will help to guide the development of effective bioremediation and biomass degradation strategies.

  19. Smokeless Tobacco May Contain Potentially Harmful Bacteria

    Science.gov (United States)

    ... 160769.html Smokeless Tobacco May Contain Potentially Harmful Bacteria Infections, diarrhea and vomiting are possible consequences, FDA ... products can harbor several species of potentially harmful bacteria, researchers warn. Two types in particular -- Bacillus licheniformis ...

  20. Pesticide Exposures May Alter Mouth Bacteria

    Science.gov (United States)

    ... fullstory_162249.html Pesticide Exposures May Alter Mouth Bacteria Study of Washington farm workers finds alterations persist ... News) -- Pesticide exposure may change the makeup of bacteria in the mouths of farm workers, a new ...

  1. Certain Bacteria May Affect Preterm Birth Risk

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_163401.html Certain Bacteria May Affect Preterm Birth Risk Bad 'bugs' tied ... Feb. 3, 2017 (HealthDay News) -- Certain types of bacteria in a pregnant woman's cervix and vagina can ...

  2. 40 CFR 721.7200 - Perfluoroalkyl aromatic carbamate modified alkyl methacrylate copolymer.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Perfluoroalkyl aromatic carbamate... Significant New Uses for Specific Chemical Substances § 721.7200 Perfluoroalkyl aromatic carbamate modified...) The chemical substance identified generically as perfluoroalkyl aromatic carbamate modified...

  3. 40 CFR 721.785 - Halogenated alkane aromatic compound (generic name).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Halogenated alkane aromatic compound... Specific Chemical Substances § 721.785 Halogenated alkane aromatic compound (generic name). (a) Chemical... as a halogenated alkane aromatic compound (PMN P-94-1747) is subject to reporting under this...

  4. 40 CFR 721.10179 - Copolymers of phenol and aromatic hydocarbon (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Copolymers of phenol and aromatic... Specific Chemical Substances § 721.10179 Copolymers of phenol and aromatic hydocarbon (generic). (a... generically as copolymers of phenol and aromatic hydocarbon (PMNs P-04-346 and P-04-347) are subject...

  5. 40 CFR 721.9620 - Aromatic sulfonic acid compound with amine.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic sulfonic acid compound with... Specific Chemical Substances § 721.9620 Aromatic sulfonic acid compound with amine. (a) Chemical substance... aromatic sulfonic acid compound with amine (PMN P-93-832) is subject to reporting under this section...

  6. Genetics of Lactic Acid Bacteria

    Science.gov (United States)

    Zagorec, Monique; Anba-Mondoloni, Jamila; Coq, Anne-Marie Crutz-Le; Champomier-Vergès, Marie-Christine

    Many meat (or fish) products, obtained by the fermentation of meat originating from various animals by the flora that naturally contaminates it, are part of the human diet since millenaries. Historically, the use of bacteria as starters for the fermentation of meat, to produce dry sausages, was thus performed empirically through the endogenous micro-biota, then, by a volunteer addition of starters, often performed by back-slopping, without knowing precisely the microbial species involved. It is only since about 50 years that well defined bacterial cultures have been used as starters for the fermentation of dry sausages. Nowadays, the indigenous micro-biota of fermented meat products is well identified, and the literature is rich of reports on the identification of lactic acid bacteria (LAB) present in many traditional fermented products from various geographical origin, obtained without the addition of commercial starters (See Talon, Leroy, & Lebert, 2007, and references therein).

  7. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    Directory of Open Access Journals (Sweden)

    NEENA GARG

    2015-10-01

    Full Text Available Lactic acid bacteria (LAB is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LAB are used as starter culture, consortium members and bioprotective agents in food industry that improve food quality, safety and shelf life. A variety of probiotic LAB species are available including Lactobacillus acidophilus, L. bulgaricus, L. lactis, L. plantarum, L. rhamnosus, L. reuteri, L. fermentum, Bifidobacterium longum, B. breve, B. bifidum, B. esselnsis, B. lactis, B. infantis that are currently recommended for development of functional food products with health-promoting capacities.

  8. Dissipative Shocks behind Bacteria Gliding

    CERN Document Server

    Virga, Epifanio G

    2014-01-01

    Gliding is a means of locomotion on rigid substrates utilized by a number of bacteria includingmyxobacteria and cyanobacteria. One of the hypotheses advanced to explain this motility mechanism hinges on the role played by the slime filaments continuously extruded from gliding bacteria. This paper solves in full a non-linear mechanical theory that treats as dissipative shocks both the point where the extruded slime filament comes in contact with the substrate, called the filament's foot, and the pore on the bacterium outer surface from where the filament is ejected. We prove that kinematic compatibility for shock propagation requires that the bacterium uniform gliding velocity (relative to the substrate) and the slime ejecting velocity (relative to the bacterium) must be equal, a coincidence that seems to have already been observed.

  9. Aggregation Patterns in Stressed Bacteria

    CERN Document Server

    Tsimring, L S; Aranson, I S; Ben-Jacob, E; Cohen, I; Shochet, O; Tsimring, Lev; Levine, Herbert; Aranson, Igor; Ben-Jacob, Eshel; Cohen, Inon; Shochet, Ofer

    1995-01-01

    We study the formation of spot patterns seen in a variety of bacterial species when the bacteria are subjected to oxidative stress due to hazardous byproducts of respiration. Our approach consists of coupling the cell density field to a chemoattractant concentration as well as to nutrient and waste fields. The latter serves as a triggering field for emission of chemoattractant. Important elements in the proposed model include the propagation of a front of motile bacteria radially outward form an initial site, a Turing instability of the uniformly dense state and a reduction of motility for cells sufficiently far behind the front. The wide variety of patterns seen in the experiments is explained as being due the variation of the details of the initiation of the chemoattractant emission as well as the transition to a non-motile phase.

  10. Re-engineering bacteria for ethanol production

    Science.gov (United States)

    Yomano, Lorraine P; York, Sean W; Zhou, Shengde; Shanmugam, Keelnatham; Ingram, Lonnie O

    2014-05-06

    The invention provides recombinant bacteria, which comprise a full complement of heterologous ethanol production genes. Expression of the full complement of heterologous ethanol production genes causes the recombinant bacteria to produce ethanol as the primary fermentation product when grown in mineral salts medium, without the addition of complex nutrients. Methods for producing the recombinant bacteria and methods for producing ethanol using the recombinant bacteria are also disclosed.

  11. Effects of biosurfactant-producing bacteria on biodegradation and transport of phenanthrene in subsurface soil.

    Science.gov (United States)

    Chang, Jae-Soo; Cha, Daniel K; Radosevich, Mark; Jin, Yan

    2015-01-01

    This study investigated the effects of surfactant-producing microorganism, Pseudomonas aeruginosa ATCC 9027, on phenanthrene (PHE) biodegradation by two different PHE-degrading bacteria (Isolate P5-2 and Pseudomonas strain R) in soil. Phenanthrene mineralization experiments were conducted with soils inoculated with one of PHE-degraders and/or the surfactant-producer. Influence of co-inoculation with the surfactant-producing bacteria on phenanthrene transport and biodegradation was also examined in soil columns. P. strain R mineralized phenanthrene faster and to a greater extent than Isolate P5-2 in the test soil. Co-inoculation with the surfactant-producing bacteria significantly enhanced phenanthrene biodegradation by P. strain R but it did not affect the biodegradation by Isolate P5-2 in both batch and column systems. Production of biosurfactants by P. aeruginosa ATCC 9027 was negligible under the given conditions. This study demonstrated that bioaugmentation with surfactant-producing bacteria could enhance in situ bioremediation of soils contaminated with polycyclic aromatic hydrocarbons (PAHs) and the beneficial effect of the bioaugmentation depended on types of PAH-degrading microorganisms present.

  12. Compartmentalization of bacteria in microcapsules.

    Science.gov (United States)

    van Wijk, Judith; Heunis, Tiaan; Harmzen, Elrika; Dicks, Leon M T; Meuldijk, Jan; Klumperman, Bert

    2014-12-18

    Lactobacillus plantarum strain 423 was encapsulated in hollow poly(organosiloxane) microcapsules by templating water-in-oil Pickering emulsion droplets via the interfacial reaction of alkylchlorosilanes. The bacteria were suspended in growth medium or buffer to protect the cells against pH changes during the interfacial reactions with alkylchlorosilanes. The results of this work open up novel avenues for the encapsulation of microbial cells.

  13. Polycyclic aromatic hydrocarbons as plausible prebiotic membrane components.

    Science.gov (United States)

    Groen, Joost; Deamer, David W; Kros, Alexander; Ehrenfreund, Pascale

    2012-08-01

    Aromatic molecules delivered to the young Earth during the heavy bombardment phase in the early history of our solar system were likely to be among the most abundant and stable organic compounds available. The Aromatic World hypothesis suggests that aromatic molecules might function as container elements, energy transduction elements and templating genetic components for early life forms. To investigate the possible role of aromatic molecules as container elements, we incorporated different polycyclic aromatic hydrocarbons (PAH) in the membranes of fatty acid vesicles. The goal was to determine whether PAH could function as a stabilizing agent, similar to the role that cholesterol plays in membranes today. We studied vesicle size distribution, critical vesicle concentration and permeability of the bilayers using C(6)-C(10) fatty acids mixed with amphiphilic PAH derivatives such as 1-hydroxypyrene, 9-anthracene carboxylic acid and 1,4 chrysene quinone. Dynamic Light Scattering (DLS) spectroscopy was used to measure the size distribution of vesicles and incorporation of PAH species was established by phase-contrast and epifluorescence microscopy. We employed conductimetric titration to determine the minimal concentration at which fatty acids could form stable vesicles in the presence of PAHs. We found that oxidized PAH derivatives can be incorporated into decanoic acid (DA) vesicle bilayers in mole ratios up to 1:10 (PAH:DA). Vesicle size distribution and critical vesicle concentration were largely unaffected by PAH incorporation, but 1-hydroxypyrene and 9-anthracene carboxylic acid lowered the permeability of fatty acid bilayers to small solutes up to 4-fold. These data represent the first indication of a cholesterol-like stabilizing effect of oxidized PAH derivatives in a simulated prebiotic membrane.

  14. Metabolic activation of aromatic amines and azo dyes.

    Science.gov (United States)

    Bartsch, H

    1981-01-01

    Aromatic amines, amides and nitro compounds are a class of chemicals that produce tumors in a wide variety of tissues in experimental animals, including liver, urinary bladder, forestomach, small intestine, Zymbal's gland, subcutaneous tissue or skin. In man, exposure to some aromatic amines is associated with tumours of the urinary bladder and carcinoma of the renal pelvis. Their biological activity as carcinogens or genotoxic agents is, in all the cases that have been studied in detail, dependent on metabolic activation in vivo, occurring by multiple pathways. Differences in these metabolic pathways may largely account for the differences in tissues and species susceptibilities to cancer induction. Carcinogenicity of aromatic amines or amides is dependent on their oxidation to N-hydroxy derivatives, whilst the carcinogenicity of aromatic nitro compounds is linked to their reduction to hydroxylamines. Further conversion of the N-hydroxylamine or N-hydroxyamide to reactive intermediates can occur in several ways, which include (i) esterification of the N-hydroxy group, (ii) non-enzymic protonation of the nitrogen of the hydroxylamine and (iii) oxidation to a free radical of arylhydroxamic acids. Following generation of such reactive electrophilic intermediates in tissues or cells, macromolecular binding has been observed to nucleic acids and proteins. In many cases, arylamidated and arylaminated products are formed with nucleic acid bases; in the case of the well-studied 2-acetylaminofluorene, nucleophilic atoms of guanine are the predominant site of reaction. Relatively little is known of the structure and biological consequences of DNA adducts formed from other aromatic amines, amides or nitro compounds; more research in these directions is warranted.

  15. Characterization of Mediterranean Magnetotactic Bacteria

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Magnetotactic bacteria are a diverse group of motile prokaryotes that are ubiquitous in aquatic habitats and cosmopolitan in distribution. In this study, we collected magnetotactic bacteria from the Mediterranean Sea. A remarkable diversity of morphotypes was observed, including muiticellular types that seemed to differ from those previously found in North and South America. Another interesting organism was one with magnetosomes arranged in a six-stranded bundle which occupied one third of the cell width. The magnetosome bundle was evident even under optic microscopy. These cells were connected together and swam as a linear entire unit. Magnetosomes did not always align up to form a straight linear chain. A chain composed of rectangle magnetosomes bent at a position with an oval crystal. High resolution transmission electron microscopy analysis of the crystal at the pivotal position suggested uncompleted formation of the crystal. This is the first report of Mediterranean magnetotactic bacteria, which should be useful for studies of biogeochemical cycling and geohistory of the Mediterranean Sea.

  16. Ecology of mycophagous collimonas bacteria in soil

    NARCIS (Netherlands)

    Höppener-Ogawa, Sachie

    2008-01-01

    Bacteria belonging to the genus Collimonas consist of soil bacteria that can grow at expense of living fungal hyphae i.e. they are mycophagous. This PhD studies deals with the ecology of mycophagous bacteria in soil using collimonads as model organisms. Collimonads were found to be widely distribut

  17. Current strategies for improving food bacteria

    NARCIS (Netherlands)

    Kuipers, O P; Buist, Girbe; Kok, Jan

    2000-01-01

    Novel concepts and methodologies are emerging that hold great promise for the directed improvement of food-related bacteria, specifically lactic acid bacteria. Also, the battle against food spoilage and pathogenic bacteria can now be fought more effectively. Here we describe recent advances in micro

  18. Electron transport chains of lactic acid bacteria

    NARCIS (Netherlands)

    Brooijmans, R.J.W.

    2008-01-01

    Lactic acid bacteria are generally considered facultative anaerobic obligate fermentative bacteria. They are unable to synthesize heme. Some lactic acid bacteria are unable to form menaquinone as well. Both these components are cofactors of respiratory (electron transport) chains of prokaryotic bact

  19. Laser-Based Identification of Pathogenic Bacteria

    Science.gov (United States)

    Rehse, Steven J.

    2009-01-01

    Bacteria are ubiquitous in our world. From our homes, to our work environment, to our own bodies, bacteria are the omnipresent although often unobserved companions to human life. Physicists are typically untroubled professionally by the presence of these bacteria, as their study usually falls safely outside the realm of our typical domain. In the…

  20. Nitrogen-fixing methane-utilizing bacteria

    NARCIS (Netherlands)

    Bont, de J.A.M.

    1976-01-01

    Methane occurs abundantly in nature. In the presence of oxygen this gas may be metabolized by bacteria that are able to use it as carbon and energy source. Several types of bacteria involved in the oxidation of methane have been described in literature. Methane-utilizing bacteria have in common that