25 research outputs found
Candida rugosa lipase immobilized onto titania: improved thermal stability and reuse potential
Enzyme catalyzed reactions have been extensively exploited for a wide range of applications in biotechnology. In spite of a broad implementation of enzymes in different fields, some constraints referred to their cost and process stability still exists. To overcome a limit related to short catalytic lifetime of enzymes in process conditions, a spectrum of immobilization methods have been extensively studied to increase stability and enhance reuse, offer easier separation, making production economically viable.V International Conference on Radiation in Various Fields of Research : RAD 2017 : book of abstracts; June 12-16, 2017; Budva, Montenegr
Supplementary data for the article: Izrael Živković, L. T.; Živković, L. S.; Beškoski, V. P.; Gopčević, K. R.; Jokić, B. M.; Radosavljević, D. S.; Karadžić, I. M. The Candida Rugosa Lipase Adsorbed onto Titania as Nano Biocatalyst with Improved Thermostability and Reuse Potential in Aqueous and Organic Media. Journal of Molecular Catalysis B: Enzymatic 2016, 133, S533–S542. https://doi.org/10.1016/j.molcatb.2017.06.001
Supplementary material for: [https://doi.org/10.1016/j.molcatb.2017.06.001]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/315]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3648
Candida rugosa lipase immobilized onto titania as nanobiocatalyst in organic solvent
Kinetic measurements can be used to predict the optimum kinetic behaviour of a particular biocatalyst. Based on those predictions, optimisation of biocatalytic reactions, as well as process design to improve productivity and reduce the cost of various processes can be performed.V International Conference on Radiation in Various Fields of Research : RAD 2017 : book of abstracts; June 12-16, 2017; Budva, Montenegr
Pseudomonas lipase catalyzed synthesis of ergosterol oleate
Poster presented at 7th Balkan Congress of Microbiology and 8th Congress of Serbian Microbiologists, Belgrade, October 25-29, 2011Abstract: [https://cer.ihtm.bg.ac.rs/handle/123456789/5200
The Candida rugosa lipase adsorbed onto titania as nano biocatalyst with improved thermostability and reuse potential in aqueous and organic media
The immobilization of Candida rugosa lipase by adsorption was performed onto commercial titania powder (Degussa P25). The change of titania particles surface was diagnosed by means of FTIR and FESEM analysis, as well as by shift of zeta potential value towards that of lipase. A detailed study of the effect of immobilization on enzyme kinetic, temperature stability, as well as on potential for its reuse in aqueous organic media was undertaken. Immobilization of lipase altered enzyme affinity toward substrates with different length of carbon chain in hydrolytic reaction. The Vmax value decreased 2–8-fold, where major constraint was registered for the ester containing the longest carbon chain. Thermostability of lipase improved more than 7-fold at 60 °C. Significant potential for reuse in water solutions was also found after immobilization. In cyclohexane immobilized lipase catalyzed synthesis of amyl octanoate by ping-pong bi–bi mechanism with inhibition by amyl alcohol. Obtained kinetic constants were Vmax = 26.4 μmol min−1, KAc = 0.52 mol/L, KAl = 0.2 mol/L and Ki,Al = 0.644 mol/L. Esterification activity remained 60% after 5 reuse cycles in cyclohexane indicating moderate reuse stability. © 2017 Elsevier B.V.This is peer-reviewed version of the following article: Izrael Živković, L. T.; Živković, L. S.; Beškoski, V. P.; Gopčević, K. R.; Jokić, B. M.; Radosavljević, D. S.; Karadžić, I. M. The Candida Rugosa Lipase Adsorbed onto Titania as Nano Biocatalyst with Improved Thermostability and Reuse Potential in Aqueous and Organic Media. Journal of Molecular Catalysis B: Enzymatic 2016, 133, S533–S542. [https://doi.org/10.1016/j.molcatb.2017.06.001]Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3649
Supplementary data for the article: Izrael Živković, L. T.; Živković, L. S.; Beškoski, V. P.; Gopčević, K. R.; Jokić, B. M.; Radosavljević, D. S.; Karadžić, I. M. The Candida Rugosa Lipase Adsorbed onto Titania as Nano Biocatalyst with Improved Thermostability and Reuse Potential in Aqueous and Organic Media. Journal of Molecular Catalysis B: Enzymatic 2016, 133, S533–S542. https://doi.org/10.1016/j.molcatb.2017.06.001
Supplementary material for: [https://doi.org/10.1016/j.molcatb.2017.06.001]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/315]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3648
A comprehensive study of conditions of the biodegradation of a plastic additive 2,6-di-tertbutylphenol and proteomic changes in the degrader Pseudomonas aeruginosa san ai
The Pseudomonas aeruginosa san ai strain was investigated for its capability to degrade the 2,6-di-tertbutylphenol (2,6-DTBP) plastic additive, a hazardous and toxic substance for aquatic life. This
investigation was performed under different parameter values: 2,6-DTBP concentration, inoculum size,
pH, and temperature. The GC-MS study showed that P. aeruginosa efficiently degraded 2,6-DTBP in the
pH range of 5–8 at higher temperatures. Under exposure to 2,6-DTBP concentrations of 2, 10, and
100 mg L 1
, the strain degraded by 100, 100, and 85%, respectively, for 7 days. Crude enzyme
preparation from the biomass of P. aeruginosa san ai showed higher efficiency in 2,6-DTBP removal
than that shown by whole microbial cells. Gene encoding for the enzymes involved in the degradation of
aromatic compounds in P. aeruginosa san ai was identified. To complement the genomic data,
a comparative proteomic study of P. aeruginosa san ai grown on 2,6-DTBP or sunflower oil was
conducted by means of nanoLC-MS/MS. The presence of aromatic substances resulted in the
upregulation of aromatic ring cleavage enzymes, whose activity was confirmed by enzymatic tests;
therefore, it could be concluded that 2,6-DTBP might be degraded by ortho-ring cleavage. A
comparative proteomics study of P. aeruginosa san ai indicated that the core molecular responses to
aromatic substances can be summarized as the upregulation of proteins responsible for amino acid
metabolism with emphasized glutamate metabolism and energy production with upregulated enzymes
of glyoxylate bypass. P. aeruginosa san ai has a high capacity to efficiently degrade aromatic
compounds, and therefore its whole cells or enzymes could be used in the treatment of contaminated
area
Bioactivity and phenolics profile of aqueous and ethyl acetate extracts of Satureja kitaibelii Wierzb. ex Heuff. obtained by ultrasound-assisted extraction
The aim of the study was to investigate the biological activity and chemical composition of Satureja kitaibelii Wierzb. ex Heuff. LC–PDA/MS analyses for the aqueous extracts (A1-stem, leaves and flowers, A2-leaves and flowers) and ethyl-acetate extracts (E1-stem, leaves and flowers, E2-leaves and flowers) obtained by ultrasound-assisted extraction enabled the identification of thirty-four compounds. Quantitative analysis revealed that the aqueous extract obtained from leaves and flowers was the richest in total phenolic acids (65.36 mg/g) and flavonoids (21.17 mg/g). The total polyphenol content was the highest in the aqueous extract obtained from leaves and flowers (274 ± 2.4 mg Gallic Acid equivalents/g). The best antioxidant activity was observed for the same extract using the DPPH (SC50 20 ± 10 µg/mL), ABTS (2.834 ± 0.02 mg Ascorbic Acid/g), FRAP (1.922 ± 0.03 mmol Fe2+/mg), and total reducing power tests (16.4 ± 1.0 mg Ascorbic Acid/g). Both ethyl acetate extracts were the most active against strains of Bacillus cereus and Micrococcus flavus (MIC 1.70–1.99 mg/mL and 1.99–3.41 mg/mL, respectively). They were more efficient against Aspergillus ochraceus (MFC 0.86 mg/mL) and towards HeLa cell lines. All the obtained results implied the good potential of the investigated extracts to be used as effective preservatives and functional ingredients in food products and dietary supplements
Supplementary material for the article: Izrael-Živković, L.; Rikalović, M.; Gojgić-Cvijović, G.; Kazazić, S.; Vrvić, M.; Brčeski, I.; Beškoski, V.; Lončarević, B.; Gopčević, K.; Karadžić, I. Cadmium Specific Proteomic Responses of a Highly Resistant: Pseudomonas Aeruginosa San Ai. RSC Advances 2018, 8 (19), 10549–10560. https://doi.org/10.1039/c8ra00371h
Supplementary material for: [https://doi.org/10.1039/c8ra00371h]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2118
Cadmium specific proteomic responses of a highly resistant Pseudomonas aeruginosa san ai
Pseudomonas aeruginosa san ai is a promising candidate for bioremediation of cadmium pollution, as it resists a high concentration of up to 7.2 mM of cadmium. Leaving biomass of P. aeruginosa san ai exposed to cadmium has a large biosorption potential, implying its capacity to extract heavy metal from contaminated medium. In the present study, we investigated tolerance and accumulation of cadmium on protein level by shotgun proteomics approach based on liquid chromatography and tandem mass spectrometry coupled with bioinformatics to identify proteins. Size exclusion chromatography was used for protein prefractionation to preserve native forms of metalloproteins and protein complexes. Using this approach a total of 60 proteins were observed as up-regulated in cadmium-amended culture. Almost a third of the total numbers of up-regulated were metalloproteins. Particularly interesting are denitrification proteins which are over expressed but not active, suggesting their protective role in conditions of heavy metal exposure. P. aeruginosa san ai developed a complex mechanism to adapt to cadmium, based on: extracellular biosorption, bioaccumulation, the formation of biofilm, controlled siderophore production, enhanced respiration and modified protein profile. An increased abundance of proteins involved in: cell energy metabolism, including denitrification proteins; amino acid metabolism; cell motility and posttranslational modifications, primarily based on thiol-disulfide exchange, were observed. Enhanced oxygen consumption of biomass in cadmium-amended culture versus control was found. Our results signify that P. aeruginosa san ai is naturally well equipped to overcome and survive high doses of cadmium and, as such, has a great potential for application in bioremediation of cadmium polluted sites.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3179