Wyniki wyszukiwania - Biblioteka Nauki

1

Modulation of FAD-dependent monooxygenase activity from aromatic compounds-degrading Stenotrophomonas maltophilia strain KB2

100%

Wojcieszyńska D. , Greń I. , Hupert-Kocurek K. , Guzik U.

Acta Biochimica Polonica

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2011

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tom 58

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nr 3

421-426

EN

The purpose of this study was purification and characterization of phenol monooxygenase from Stenotrophomonas maltophilia strain KB2, enzyme that catabolises phenol and its derivatives through the initial hydroxylation to catechols. The enzyme requires NADH and FAD as a cofactors for activity, catalyses hydroxylation of a wide range of monocyclic phenols, aromatic acids and dihydroxylated derivatives of benzene except for catechol. High activity of this monooxygenase was observed in cell extract of strain KB2 grown on phenol, 2-methylphenol, 3-metylphenol or 4-methylphenol. Ionic surfactants as well as cytochrome P450 inhibitors or 1,4-dioxane, acetone and n-butyl acetate inhibited the enzyme activity, while non-ionic surfactants, chloroethane, ethylbenzene, ethyl acetate, cyclohexane, and benzene enhanced it. These results indicate that the phenol monooxygenase from Stenotrophomonas maltophilia strain KB2 holds great potential for bioremediation.

2

Influence of the entrapment of catechol 2,3-dioxygenase in kappa-carrageenan on its properties

88%

Wojcieszynska D. , Hupert-Kocurek K. , Guzik U.

Polish Journal of Environmental Studies

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2013

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tom 22

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nr 4

EN

Microbial extradiol dioxygenases have a great potential in bioremediation, but their structure is very sensitive to various environmental and chemical agents. Immobilization techniques make the enzyme properties’ improvement possible. This is the first report of the usage of κ-carrageenan as a matrix for the immobilization of catechol 2,3-dioxygenase. The storage stability of entrapped catechol 2,3-dioxygenase from Stenotrophomonas maltophilia KB2 in κ-carrageenan hydrogel at 4ºC was found up to 14 days, while the free enzyme lost its activity within 24 hours. The immobilization of dioxygenase decreased the optimum temperature by 10ºC, while both soluble and immobilized enzyme showed similar pH properties. The Km, Vmax, and Hill constant values for the immobilized enzyme were 0.17 μM, 106.68 mU, and 1.00, respectively. The immobilized catechol 2,3-dioxygenase showed higher activity against 3-methylcatechol, hydroquinone, and tetrachlorohydroquinone than the soluble enzyme. Immobilization of catechol 2,3-dioxygenase protected the enzyme from inhibition and enhanced its resistance to inactivation during catalysis.

3

Isolation and characterization of an endosulfan-degrading strain, Stenotrophomonas sp. LD-6, and its potential in soil bioremediation

75%

Yu F.-B. , Shinawar W. A. , Sun J.-Y. , Luo L.-P.

Polish Journal of Microbiology

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2012

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tom 61

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nr 4

EN

Aerobic bacteria degrading endosulfan were isolated from contaminated sludge. One of the isolates, LD-6, was identified as Stenotrophomonas sp. The bacterium could utilize endosulfan as the sole source of carbon and sulfur. 100 mg/l endosulfan was completely degraded within 10 days, and endosulfan diol and endosulfan ether were detected as major metabolites with a slight decrease in culture pH. The results indicated that Stenotrophomonas. sp. LD-6 might degrade endosulfan by a non-oxidative pathway. Biodegradation of both isomers was relatively better at a temperature range of 25–35°C, with a maximum at 30°C. In addition, cell crude extract of strain LD-6 could metabolize endosulfan rapidly, and degradative enzymes were intracellular distributed and constitutively expressed. Besides, application of the strain was found to promote the removal of endosulfan in soil. This study might help with the future research in better understanding of the biodegradation.

4

Badania aktywności dioksygenaz katecholowych w obecności jonów wybranych metali ciężkich w aspekcie bioremediacji środowisk zanieczyszczonych związkami aromatycznymi

63%

Guzik U. , Wojcieszyńska D. , Greń I. , Hupert-Kocurek K.

Ochrona Środowiska

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2010

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tom Vol. 32, nr 1

9-13

PL

Szczepy bakterii Stenotrophomonas maltophilia KB2 oraz Pseudomonas putida N6 odznaczają się zwiększoną zdolnością do degradacji związków aromatycznych. W badaniach stwierdzono całkowity rozkład fenolu (3 mmol/dm3) w ciągu pięciu godzin przez oba badane szczepy. U szczepu KB2 po indukcji fenolem wykazano obecność 2,3-dio-ksygenazy katecholowej odpowiedzialnej za meta-rozszczepienie związków aromatycznych, natomiast u szczepu Pseudomonas putida N6 wykazano obecność 1,2-dioksygenazy katecholowej, charakterystycznej dla szlaku orto rozszczepienia pierścienia aromatycznego. W wyniku badań nad wrażliwością tych enzymów na obecność jonów metali wykazano, że jony Zn2+ aktywowały 2,3-dioksygenazę katecholową szczepu KB2. Wszystkie pozostałe jony były inhibitorami tego enzymu. Spośród przebadanych jonów metali najsilniejszym inhibitorem obu wyizolowanych dioksygenaz okazał się jon Cu2+, natomiast w mniejszym stopniu aktywność 1,2-dioksygenazy katecholowej szczepu N6 hamowały Cd2+ i Zn2+. Wzrost aktywności tego enzymu zaobserwowano w obecności Co2+. Pozostałe jony metali nie wpłynęły znacząco na aktywność 1,2-dioksygenazy katecholowej szczepu N6. Stwierdzona w badaniach częściowa aktywność obu badanych dioksygenaz po zastosowaniu soli metali sugeruje możliwość wykorzystania szczepów bakterii Stenotrophomonas maltophilia KB2 oraz Pseudomonas putida N6 do oczyszczania środowisk skażonych związkami aromatycznymi.

EN

The strains of Stenotrophomonas maltophilia KB2 and Pseudomonas putida N6 are characterized by an enhanced capacity for degrading aromatic compounds: within five hours of incubation both the strains were found to provide a complete degradation of phenol (3 mmol/dm3). Upon induction with phenol, catechol 2,3-dioxygenase, an enzyme responsible for the meta-cleavage of aromatic compounds, was detected in the Stenotrophomonas maltophilia KB2 strain, whereas in the Pseudomonas putida N6 strain the presence was revealed of catechol 1,2-dioxygenase, an enzyme characteristic of the pathway for the orthofission of the aromatic ring. Tests on the sensitivity of the enzymes to metal ions have demonstrated that Zn2+ ions activated catechol 2,3-dioxygenase in the KB2 strain. The other metal ions were found to be inhibitors of this enzyme. Among the metal ions tested, the Cu2+ ion was the strongest inhibitor of the two isolated dioxynases. Slightly weaker was the inhibition of catechol 1,2-dioxygenase induced by Cd2+ and Zn2+ ions in the N6 strain. The activity of this enzyme increased in the presence of Co2+ ions. The other ions had no significant influence on the activity of the catechol 1,2-dioxygenase isolated from the N6 strain. The partial activity of both dioxygenases observed upon the application of metal salts suggests that both the strains, Stenotrophomonas maltophilia KB2 and Pseudomonas putida N6, may contribute much to the remediation of an environment polluted with aromatic compounds.

5

Enrichment, isolation and susceptibility profile of the growth substrate of bacterial strains able to degrade vinyl acetate

51%

Gren I. , Gaszczak A. , Szczyrba E. , Labuzek S.

Polish Journal of Environmental Studies

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2009

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tom 18

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nr 3

383-390

EN

Nowadays biodegradations of harmful xenobiotics seems to be the best and cheapest method of purification of the polluted environment. VOCs are represented by vinyl acetate, which is thought to be carcinogenic. The aim of these studies was to isolate and determine the susceptibility profile for vinyl acetate of bacterial strains. The source of microorganisms was soil sampled in the area of Synthos S.A. in Oświęcim, Poland. From among 41 isolates, 4 Gram-negative strains were chosen for further analyses. As the control, one laboratory strain of Pseudomonas fluorescens PCM 2123 from The Polish Collection of Microorganisms (Wrocław) was used. Simultaneously, a susceptibility profile to vinyl acetate was performed on Stenotrophomonas maltophilia KB2 strain, aromatic compounds’ degrader. Vinyl acetate used in concentration of 3,000 ppm inhibited growth of gram-positive bacteria, and 4,000 ppm was the lethal dose for microorganisms from mixed populations. A toxicity test showed susceptibility to vinyl acetate at concentrations of 2,000 ppm. Three weeks of pre-incubation with 400 ppm of vinyl acetate magnified the level of sensitivity to 3,000 ppm of vinyl acetate for almost all strains. Although decomposition of vinyl acetate was observed even in the presence of 4,000, 5,000 and 6,000 ppm of vinyl acetate, growth was not observed. It was due to enlarged concentration of acetaldehyde, a product of hydrolysis ester bond of vinyl acetate.