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Lalevic B.,University of Belgrade | Raicevic V.,University of Belgrade | Kikovic D.,University of Tirana | Jovanovic L.,Educons University | And 4 more authors.
International Journal of Environmental Research | Year: 2012

Methyl tertiary butyl ether (MTBE) belongs to the group of gasoline oxygenates and persistent environment contaminants, and shows potential for biodegradation in aerobic and anaerobic conditions, through application of pure microbial cultures. Presented research shows that indigenous bacterial isolates 6sy and 24p, selected from oil hydrocarbons-contaminated environments, were capable of utilizing MTBE as sole carbon and energy source. Based on 16S rDNA sequence analysis, bacterial isolates 6sy and 24p were identified as Staphylococcus saprophyticus subsp. saprophyticus and Pseudomonas sp., respectively. The MTBE biodegradation rate was affected by longevity of incubation period and initial MTBE concentration. After 3 weeks of incubation at 25°C in a dark, the removal rates of initial 25 and 125 ppm MTBE concentrations by Staphylococcus saprophyticus 6sy were found to be 97, and 63%, respectively, while efficiency of Pseudomonas sp. in degradation of indicated concentrations was 96, and 40%, respectively. Both bacterial isolates were able to grow in MTBE-containing growth medium. Highest growth rate of bacterial isolates was observed at the end of incubation period. The presented results indicated the potential of these bacterial isolates in bioremediation of MTBE-contaminated environments.


Kikovic D.,University of Tirana | Jovanovic L.,Educons University | Jovic J.,Institute for Plant Protection and Environment | Talaie A.R.,Jami Institute of Technology | Morina F.,Institute for multidisciplinary researches
International Journal of Environmental Research | Year: 2011

Methyl tertiary butyl ether (MTBE) belongs to the group of gasoline oxygenates and persistent environment contaminants, and shows potential for biodegradation in aerobic and anaerobic conditions, through application of pure microbial cultures. Presented research shows that indigenous bacterial isolates 6sy and 24p, selected from oil hydrocarbons-contaminated environments, were capable of utilizing MTBE as sole carbon and energy source. Based on 16S rDNA sequence analysis, bacterial isolates 6sy and 24p were identified as Staphylococcus saprophyticus subsp. saprophyticus and Pseudomonas sp., respectively. The MTBE biodegradation rate was affected by longevity of incubation period and initial MTBE concentration. After 3 weeks of incubation at 25°C in a dark, the removal rates of initial 25 and 125 ppm MTBE concentrations by Staphylococcus saprophyticus 6sy were found to be 97, and 63%, respectively, while efficiency of Pseudomonas sp. in degradation of indicated concentrations was 96, and 40%, respectively. Both bacterial isolates were able to grow in MTBE-containing growth medium. Highest growth rate of bacterial isolates was observed at the end of incubation period. The presented results indicated the potential of these bacterial isolates in bioremediation of MTBE-contaminated environments.


Bobic J.D.,Institute for multidisciplinary researches | Vijatovic M.M.,Institute for multidisciplinary researches | Greicius S.,Vilnius University | Banys J.,Vilnius University | Stojanovic B.D.,Institute for multidisciplinary researches
Journal of Alloys and Compounds | Year: 2010

Barium bismuth titanate BaBi4Ti4O15 (BBiT) ceramics have been prepared using non-conventional solid-state reaction route based on mechanochemical synthesis during intensive milling. The X-ray diffraction method was used to determine phase composition. Dielectric properties were investigated in a wide range of temperatures (20-800 °C) and frequencies (1.21 kHz-1 MHz). The broad dielectric constant peaks at temperature Tm is frequently dependent. A modified Curie-Weiss relationship is used to study the diffuseness behavior of a ferroelectric phase transition where value of γ indicates the degree of diffuseness of barium bismuth titanate ceramics. The dielectric relaxation rate follows the Vogel-Fulcher relation with Ea = 0.013 eV, ν0 = 2.09 × 108 Hz and Tf = 651 K. All these parameters indicate that BaBi4Ti4O15 is a relaxor ferroelectric. Ohmic conductivities and associated activation energies were evaluated using impedance spectroscopy. © 2010 Elsevier B.V. All rights reserved.

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