85 research outputs found
Green synthesis of silver nanoparticles using Bacillus licheniformis strain
The development of eco-friendly technologies in different areas, as well as in nanotechnology, is of great importance to the expansion of the many biological applications of microrganisms. In this work, the synthesis of silver nanoparticles by the reduction of aqueous Ag+ ions using the non-pathogenic bacterial strain B. licheniformis, under mild conditions, was investigated. The synthesized nanoparticles were characterized by UVāVis spectroscopy, scanning electron
microscopy (SEM), and electron diffraction spectroscopy (EDX)
Exopolysaccharides from Bacillus licheniformis: Production, partial characterization and emulsifying activity
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/123456789/5271
Efekti antibiotika koji deluju na Äelijske membrane na srce pacova
The effect of some membrane active ionophoric antibiotics on the amplitude of contractions of isolated rat heart right ventricle was studied. The effects of polyether nigericin, polyene amphotericin B and peptide antibiotic polymyxin B were examined. Nigericin in a concentration of 1.38 _mol/L exerts a positive inotropic effect with its maximal value (+29%) 15 minutes after application. Amphotericin B in a concentration of 1.08 _mol/L caused a positive inotropic effect, which was maximal in the 30th minute of the experiment (+28%). Polymyxin B in a concentration of 0.84 _mol/L caused a positive inotropic effect, which was maximal (+32%) 20 minutes after application.Amfotericin B, nigericin i polimiksin B pokazuju pozitivni inotropni efekat na izolovanu desnu komoru srca pacova. ImajuÄi u vidu nižu toksiÄnost jonofornih antibiotika u poreÄenju sa glikozidnim supstancama koje se u farmakoterapiji koriste kao kardiotonici i visoku selektivnost jonofora prema nekim katjonima, dobijeni rezultati ukazuju na moguÄu upotrebu ovih supstanci u poboljÅ”anju funkcije insuficijentnog miokarda
Exopolysaccharides from Bacillus licheniformis: Production, partial characterization and emulsifying activity
The aim of the present study was to compare growth and EPS production of Bacillus licheniformis in two different media, and to partially characterize isolated polysaccharides.Poster: [https://cer.ihtm.bg.ac.rs/handle/123456789/5272
Oxidative transformation of levan produced by Bacillus licheniformis strain
In this work microbial polysacharide levan produced by Bacillus licheniformis NS032 was functionalized by introducing aldehyde groups into glycan chains. Resulting polyaldechide polymer was characterized by FT-IR spectral analysis and the content of aldehyde groups was determined titrimetrically
Biodegradation Assessment of Poly(Urethane-Dimethylsiloxane)/Organoclay Nanocomposites under Environmental Conditions
The first series of polyurethane network nanocomposites (PUNN) was prepared by in situ polymerization [1,2] from poly(dimethylsiloxane)-based prepolymer as the soft segment and 4,4ā-methylene diphenyldiisocyanate and hyperbranched polyester of the third pseudo generation as the hard segment, in the presence of organically modified montmorillonite nanofiller (Cloisite 30B; 0.5 wt.%). The second series of pure polyurethane networks (PUN) without organoclay was also prepared. The composition of prepared materials in both series was varied through variation of soft segment content from 30 to 60 wt.%. Biodegradability of prepared materials was measured using mixed cultures of microorganisms that originated from soil. This test used soil bacteria and fungi to assess the impact of the environment on polymer compounds. This test is intended to determine which polymer compositions are best suited for coating other materials that must endure lengthy exposure to harsh environmental conditions while retaining their principal functionalities. The biodegradation test was performed under aerobic conditions in the dark condition and in a thermostat at 28 Ā°C. Bacterial and fungal mixed cultures were alternated monthly. After 3 and 6 months of the test, the materials were washed with water, dried in a vacuum oven to constant weight, and used for gravimetric measurements of weight loss. The prepared materials before and after biodegradation test were characterized by FTIR spectroscopy. The results showed that pure PUNs (18.35-18.66 wt.% after six months) possess the highest weight loss as compared to PUNNs (from 7.53 to 14.78 wt.% after six months) after incubation of up to six months. PUNN films had lower biodegradation degree as compared the pure PUN films. Biodegradability was lower for materials with lower soft segment content. In FTIR spectra of PUNN after biodegradation differences were noted at approximately 1700-1735 and 3324 cm-1. The structures contributing to strong hydrogen bonds were partially destroyed during the biodegradation process. The results showed that PUNN with 40 wt.% of soft segment (PUNN-40) is the most resistance material to biodegradation. The reason was probably due to more hydrogen bonding between the polymer and Cloisite 30B organoclay and its better mechanical properties of PUNN-40 sample as compared to other prepared PUNN materials. The obtained materials are good candidate as top coating materials exposed to the environmental conditions
Supplementary material for the article: LonÄareviÄ, B.; LjeÅ”eviÄ, M.; MarkoviÄ, M.; AnÄelkoviÄ, I.; GojgiÄ-CvijoviÄ, G.; JakovljeviÄ, D.; BeÅ”koski, V. Microbial Levan and Pullulan as Potential Protective Agents for Reducing Adverse Effects of Copper on Daphnia Magna and Vibrio Fischeri. Ecotoxicology and Environmental Safety 2019, 181, 187ā193. https://doi.org/10.1016/j.ecoenv.2019.06.002
Supplementary material for: [https://www.sciencedirect.com/science/article/pii/S014765131930630X?via%3Dihub]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/3158
The influence of low-frequency magnetic field regions on the Saccharomyces cerevisiae respiration and growth
The influence of four low-frequency magnetic field (MF) ranges 10ā300 Hz, 10ā100 Hz, 10ā50 Hz and 50ā100 Hz in scanning regime (all frequencies from selected range were scanned during 100 s repetitively during 24 h) on baker's yeast cells Saccharomyces cerevisiae was examined by continuous measurements of cumulative O2 consumption and cumulative CO2 production over 24 h with Micro-OxymaxĀ® respirometer. Besides respiration activity, measurements of cell growth and glucose uptake were performed as well. Statistical analysis indicated that, among all investigated low-frequency MF ranges, range from 10 Hz to 50 Hz had the greatest influence to yeast cell respiration and cell growth. More precisely, for this region, paired two sample one-tail t-test showed statistically significant differences in cumulative O2 consumption, cumulative CO2 production and S. cerevisiae cell number. Moreover samples exposed to MF range from 10 Hz to 50 Hz showed the same behavior in all five replicates: lower cumulative O2 consumption, higher cumulative CO2 production and higher cell number compared to control sample. This could be important from the application aspect, in industry (food, feed, brewery etc.) and biotechnology, because changes in cells metabolism are not caused by chemical treatment.Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/3321
Promena izoprenoidne, steranske i terpanske frakcije tokom ex situ bioremedijacije mazuta na industrijskom nivou
This paper presents the results of an ex situ bioremediation of soil contaminated by mazut (heavy residual fuel oil) in the field scale (600 m(3)). The treatment-bed (thickness 0.4 m) consisted of mechanically mixed mazut-contaminated soil, softwood sawdust as an additional carbon source and crude river sand, as a bulking and porosity increasing material. The inoculation/reinoculation was conducted periodically using a biomass of a consortium of zymogenous microorganisms isolated from a bioremediation substrate. The biostimulation was performed through addition of nutritious substances (N, P and K). The aeration was improved by systematic mixing of the bioremediation system. After 50 days, the number of hydrocarbon degraders had increased a 100 fold. Based on the changes in the group composition, the average biodegradation rate during bioremediation was 24 mg kg(-1) day(-1) for the aliphatic fraction, 6 mg kg(-1) day(-1) for the aromatic fraction and 3 mg kg(-1) day(-1) for the nitrogen-sulphur-oxygen compounds (NSO)-asphaltene fraction. In the saturated hydrocarbon fraction, gas chromatography-mass spectrometry (GC-MS) in the single ion-monitoring mode (SIM) was applied to analyse isoprenoids pristane and phytane and polycyclic molecules of sterane and triterpane type. Biodegradation occurred during the bioremediation process, as well as a reduction of the relative quantities of isoprenoids, steranes, tri- and tetracyclic terpanes and pentacyclic terpanes of the hopane type.Prikazani su rezultati ex situ bioremedijacije zemljiÅ”ta kontaminiranog mazutom na industrijskom nivou (600 m3). Bioremedijacioni materijal (debljine 0,4 m) se sastojao od mehaniÄki pomeÅ”anih mazutom zagaÄenog zemljiÅ”ta, Äamove piljevine kao dodatnog izvora ugljenika i nepreÄiÅ”Äenog reÄnog peska, dodatog u cilju meÅ”anja i poveÄanja poroznosti. Inokulacija/reinokulacija (bioaugmentacija) je periodiÄno raÄena sa biomasom konzorcijuma zimogenih mikrooorganizama izolovanih iz supstrata za bioremedijaciju. Biostimulacija je realizovana dodatkom hranljivih supstanci (N, P i K). Aeracija je poboljÅ”avana sistematskim meÅ”anjem bioremedijacionog sistema. Nakon 50 dana broj mikroorganizama koji degradiraju ugljovodonike poveÄan je 100 puta. Na osnovu promena u grupnom sastavu proseÄna stopa biodegradacije tokom bioremedijacije je bila za alifatiÄnu frakciju 24 mg kg-1 po danu, za aromatiÄnu 6 mg kg-1 po danu i 3 mg kg-1 po danu za NSO-asfaltensku frakciju. U zasiÄenoj ugljovodoniÄnoj frakciji metodom GC-MS (SIM metod) analizirani su izoprenoidi pristan i fitan i policikliÄni molekuli steranskog i triterpanskog tipa. Tokom bioremedijacionog procesa doÅ”lo je do biodegradacije i smanjenja relativnih koliÄina izoprenoida, sterana, tri- i tetracikliÄnih terpana i pentacikliÄnih terpana hopanskog tipa
Characterization of exopolysaccharide produced by Bacillus sp. NS032
In this study, the main structural monomer units and configuration of their glycosidic linkages of a exopolysaccharide obtained from a strain of Bacillus licheniformis was investigated. The chemical structure of this polymer, after purification of crude material, was analyzed by chemical methods, planar chromatography, elemental analysis and FTIR
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