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1.
Electron. j. biotechnol ; 34: 83-90, july. 2018. tab, ilus, graf
Artículo en Inglés | LILACS | ID: biblio-1047375

RESUMEN

Background: Although the functional redundancy of catechol 1,2-dioxygenase (C12O) genes has been reported in several microorganisms, limited enzymes were characterised, let alone the advantage of the coexistence of the multiple copies of C12O genes. Results: In this study, four novel C12O genes, designated catA, catAI, catAII and catAIII, in the naphthalene-degrading strain Pseudomonas putida ND6, were cloned and characterised. Phylogenetic analysis of their deduced amino acid sequences revealed that the four C12O isozymes each formed independent subtrees, together with homologues from other organisms. All four enzymes exhibited maximum activity at pH 7.4 and higher activity in alkaline than in acidic conditions. Furthermore, CatA, CatAI and CatAIII were maximally active at a temperature of 45°C, whereas a higher optimum temperature was observed for CatAII at a temperature of 50°C. CatAI exhibited superior temperature stability compared with the other three C12O isozymes, and kinetic analysis indicated similar enzyme activities for CatA, CatAI and CatAII, whereas that of CatAIII was lower. Significantly, among metal ions tested, only Cu2+ substantially inhibited the activity of these C12O isozymes, thus indicating that they have potential to facilitate bioremediation in environments polluted with aromatics in the presence of metals. Moreover, gene expression analysis at the mRNA level and determination of enzyme activity clearly indicated that the redundancy of the catA genes has increased the levels of C12O. Conclusion: The results clearly imply that the redundancy of catA genes increases the available amount of C12O in P. putida ND6, which would be beneficial for survival in challenging environments.


Asunto(s)
Pseudomonas putida/enzimología , Pseudomonas putida/genética , Catecol 1,2-Dioxigenasa/genética , Temperatura , Biodegradación Ambiental , Clonación Molecular , Catecol 1,2-Dioxigenasa/análisis , Catecol 1,2-Dioxigenasa/metabolismo , Genes Bacterianos , Concentración de Iones de Hidrógeno , Isoenzimas , Metales
2.
J Basic Microbiol ; 56(4): 369-78, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26755240

RESUMEN

Industrial effluents contaminated sites may serve as repositories of ecologically adapted efficient pyrene degrading bacteria. In the present study, six bacterial isolates from industrial effluents were purified using serial enrichment technique and their pyrene degrading potential on pyrene supplemented mineral salt medium was assessed. 16S rRNA sequence analysis showed that they belong to four bacterial genera, namely Acinetobacter, Bacillus, Microbacterium, and Ochrobactrum. Among these isolates, Bacillus megaterium YB3 showed considerably good growth and was further evaluated for its pyrene-degrading efficiency. B. megaterium YB3 could degrade 72.44% of 500 mg L(-1) pyrene within 7 days. GC-MS analysis of ethyl acetate extracted fractions detected two relatively less toxic metabolic intermediates of the pyrene degradation pathway. B. megaterium YB3 also tested positive for catechol 1, 2-dioxygenase and aromatic-ring-hydroxylating dioxygenase indole-indigo conversion assays. Considering the ability and efficiency of B. megaterium YB3 to degrade high pyrene content, the strain can be used as a tool to develop bioremediation technologies for the effective biodegradation of pyrene and possibly other PAHs in the environment.


Asunto(s)
Bacillus megaterium/aislamiento & purificación , Bacillus megaterium/metabolismo , Pirenos/metabolismo , Microbiología del Suelo , Contaminantes del Suelo/metabolismo , Acetatos/química , Bacillus megaterium/enzimología , Bacillus megaterium/genética , Biodegradación Ambiental , Catecol 1,2-Dioxigenasa/análisis , Dioxigenasas/análisis , Activación Enzimática , Carmin de Índigo/metabolismo , Hidrocarburos Policíclicos Aromáticos/metabolismo , Pirenos/química , ARN Ribosómico 16S/genética
3.
Huan Jing Ke Xue ; 27(9): 1853-7, 2006 Sep.
Artículo en Chino | MEDLINE | ID: mdl-17117644

RESUMEN

Because of the existence of some unstable factors, the effluent water from a bioaugmentation refinery wastewater treatment system usually exceeds the provided standard. To solve this problem, the relationship between the bacteria number, dehydrogenase, catechol 1,2-dioxygenase(C12O), catechol 2,3-dioxygenase(C23O) and the degradation efficiency of the bioaugmentation and control system is investigated and discussed. Using ERIC-PCR technology, we studied the changes of the microbial populations before and after treatment. The results show addition of microorganisms agent can increase the bacteria number, enzyme efficiency and the efficiency of the reactor. There exists a positive relationship between the bacteria number, C23O and the degradation efficiency in the bioaugmentation reactor. The microbial populations in both the reactors are stable before and after run. C12O is a kind of induction enzyme and its efficiency declines while the degradation efficiency increases.


Asunto(s)
Bacterias Anaerobias/metabolismo , Reactores Biológicos/microbiología , Catecol 1,2-Dioxigenasa/metabolismo , Petróleo/metabolismo , Eliminación de Residuos Líquidos/métodos , Bacterias Anaerobias/enzimología , Bacterias Anaerobias/genética , Catecol 1,2-Dioxigenasa/análisis , ADN Bacteriano/análisis , ADN Bacteriano/genética , Dioxigenasas/análisis , Dioxigenasas/metabolismo , Reacción en Cadena de la Polimerasa/métodos , Microbiología del Agua
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