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Villa Presidente Frei, Chile

Munoz P.A.,Fundacion Cientifica y Cultural Biociencia | Correa-Llanten D.N.,Fundacion Cientifica y Cultural Biociencia | Blamey J.M.,Fundacion Cientifica y Cultural Biociencia | Blamey J.M.,University of Santiago de Chile
Lipids | Year: 2014

Lipases catalyze the hydrolysis and synthesis of triglycerides and their reactions are widely used in industry. The use of ionic liquids has been explored in order to improve their catalytic properties. However, the effect of these compounds on kinetic parameters of lipases has been poorly understood. A study of the kinetic parameters of Lip1, the most thermostable lipase from the supernatant of the strain ID17, a thermophilic bacterium isolated from Deception Island, Antarctica, and a member of the genus Geobacillus is presented. Kinetic parameters of Lip1 were modulated by the use of ionic liquids BmimPF6 and BmimBF4. The maximum reaction rate of Lip1 was improved in the presence of both salts. The highest effect was observed when BmimPF6 was added in the reaction mix, resulting in a higher hydrolytic activity and in a modulation of the catalytic efficiency of the enzyme. However, the catalytic efficiency did not change in the presence of BmimBF4. The increase of the reaction rates of Lip1 promoted by these ionic liquids could be related to possible changes in the Lip1 structure. This effect was measured by quenching of tryptophan fluorescence of the enzyme, when it was incubated with each liquid salt. In conclusion, the hydrolytic activity of Lip1 is modulated by the ionic liquids BmimBF4 and BmimPF6, improving the reaction rate and the catalytic efficiency of this enzyme when BmimPF6 was used. This effect is probably due to changes in the structure of Lip1 induced by the presence of these ionic liquids, stimulating its catalytic activity. © 2014 AOCS. Source

Shah S.P.,Temple University | Jansen S.A.,Temple University | Taylor L.J.-A.,Temple University | Chong P.L.-G.,Temple University | And 3 more authors.
Chemistry and Physics of Lipids | Year: 2014

GWE1 strain is an example of anthropogenic thermophilic bacterium, recently isolated from dark crusty material from sterilization ovens by Correa-Llantén et al. (Kor. J. Microb. Biotechnol. 2013. 41(3):278-283). Thermostability is likely to arise from the adaptation of macromolecules such as proteins, lipids and nucleic acids. Complex lipid arrangement and/or type in the cell membrane are known to affect thermostability of microorganisms and efforts were made to understand the chemical nature of the polar lipids of membrane. In this work, we extracted total lipids from GWE1 cell membrane, separated them by TLC into various fractions and characterize the lipid structures of certain fractions with analytical tools such as 1H, 13C, 31P and 2D NMR spectroscopy, ATR-FTIR spectroscopy and MSn spectrometry. We were able to identify glycerophosphoethanolamine, glycerophosphate, glycerophosphocholine, glycerophosphoglycerol and cardiolipin lipid classes and an unknown glycerophospholipid class with novel MS/MS spectra pattern. We have also noticed the presence of saturated iso-branched fatty acids with NMR spectra in individual lipid classes. © 2014 Elsevier Ireland Ltd. Source

Monsalves M.T.,Fundacion Cientifica y Cultural Biociencia | Monsalves M.T.,University of Technology of Chile | Amenabar M.J.,Fundacion Cientifica y Cultural Biociencia | Ollivet-Besson G.P.,Fundacion Cientifica y Cultural Biociencia | Blamey J.M.,Fundacion Cientifica y Cultural Biociencia
Protein and Peptide Letters | Year: 2013

A thermostable superoxide dismutase from a thermophilic bacterium, called Geobacillus wiegeli (GWE1), isolated from the interior of a sterilization drying oven, was purified by anion-exchange and molecular size-exclusion liquid chromatography. On the basis of SDS-PAGE, the purified enzyme was found to be homogeneous and showed an estimated subunit molecular mass of 23.9 kDa. The holoenzyme is a homotetramer of 97.3 kDa. Superoxide dismutase exhibited maximal activity at pH 8.5 and at temperature around 60 °C. The enzyme was thermostable maintaining 50% of its activity even after 4.5 hours incubation at 60 °C and more than 70% of its activity after 30 min at 80 °C. When the microorganism was irradiated with UVA, an increase in the specific activity of superoxide dismutase was observed which was correlated with decreasing levels of anion superoxide, indicating the direct involvement of this enzyme in the capture of reactive oxygen species. This study reports the effects of UV radiation on a superoxide dismutase from a thermophilic bacterium isolated from an anthropogenic environment. © 2013 Bentham Science Publishers. Source

Correa-Llanten D.N.,Fundacion Cientifica y Cultural Biociencia | Munoz-Ibacache S.A.,Fundacion Cientifica y Cultural Biociencia | Munoz-Ibacache S.A.,University of Technology of Chile | Castro M.E.,Fundacion Cientifica y Cultural Biociencia | And 4 more authors.
Microbial Cell Factories | Year: 2013

Background: The use of microorganisms in the synthesis of nanoparticles emerges as an eco-friendly and exciting approach, for production of nanoparticles due to its low energy requirement, environmental compatibility, reduced costs of manufacture, scalability, and nanoparticle stabilization compared with the chemical synthesis.Results: The production of gold nanoparticles by the thermophilic bacterium Geobacillus sp. strain ID17 is reported in this study. Cells exposed to Au3+ turned from colourless into an intense purple colour. This change of colour indicates the accumulation of intracellular gold nanoparticles. Elemental analysis of particles composition was verified using TEM and EDX analysis. The intracellular localization and particles size were verified by TEM showing two different types of particles of predominant quasi-hexagonal shape with size ranging from 5-50 nm. The mayority of them were between 10-20 nm in size. FT-IR was utilized to characterize the chemical surface of gold nanoparticles. This assay supports the idea of a protein type of compound on the surface of biosynthesized gold nanoparticles. Reductase activity involved in the synthesis of gold nanoparticles has been previously reported to be present in others microorganisms. This reduction using NADH as substrate was tested in ID17. Crude extracts of the microorganism could catalyze the NADH-dependent Au3+ reduction.Conclusions: Our results strongly suggest that the biosynthesis of gold nanoparticles by ID17 is mediated by enzymes and NADH as a cofactor for this biological transformation. © 2013 Correa-Llantén et al.; licensee BioMed Central Ltd. Source

Munoz P.A.,Fundacion Cientifica y Cultural Biociencia | Munoz P.A.,University of Santiago de Chile | Flores P.A.,Fundacion Cientifica y Cultural Biociencia | Flores P.A.,University of Santiago de Chile | And 2 more authors.
Antarctic Science | Year: 2011

Deception Island, an active stratovolcano located in the South Shetland Islands, Antarctica, provides excellent conditions for the thermophilic bacteria growth because of high ground temperatures in specific areas, such as Fumarole Bay where the temperatures are above the mesophilic range. Denaturing Gradient Gel Electrophoresis (DGGE) was used with the 16S ribosomal gene to analyse cultures of thermophilic bacteria from a soil sample taken from Fumarole Bay. Nine bands were sequenced and analysed from DGGE and they indicated the presence of bacteria from the genera Geobacillus, Bacillus, Brevibacillus, Thermus and uncultured sulphate reducing bacteria. Some of which have been reported in other Antarctic geothermal sites. Geobacillus, Bacillus and Brevibacillus genera were successfully cultivated in an enriched medium. A pure culture of one thermophilic Geobacillus bacterium was obtained closely related to Geobacillus jurassicus. © Copyright Antarctic Science Ltd 2011. Source

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