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 UV–Vis 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 ćelijske 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. Imajući u vidu nižu toksičnost jonofornih antibiotika u poređenju sa glikozidnim supstancama koje se u farmakoterapiji koriste kao kardiotonici i visoku selektivnost jonofora prema nekim katjonima, dobijeni rezultati ukazuju na moguću upotrebu ovih supstanci u poboljšanju 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 4,4’-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 °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: Lončarević, B.; Lješević, M.; Marković, M.; Anđelković, I.; Gojgić-Cvijović, G.; Jakovljević, D.; Beškoski, 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, 187–193. 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 10–300 Hz, 10–100 Hz, 10–50 Hz and 50–100 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-Oxymax® 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 zemljišta kontaminiranog mazutom na industrijskom nivou (600 m3). Bioremedijacioni materijal (debljine 0,4 m) se sastojao od mehanički pomešanih mazutom zagađenog zemljišta, čamove piljevine kao dodatnog izvora ugljenika i neprečišćenog rečnog peska, dodatog u cilju mešanja i povećanja poroznosti. Inokulacija/reinokulacija (bioaugmentacija) je periodično rađena sa biomasom konzorcijuma zimogenih mikrooorganizama izolovanih iz supstrata za bioremedijaciju. Biostimulacija je realizovana dodatkom hranljivih supstanci (N, P i K). Aeracija je poboljšavana sistematskim mešanjem bioremedijacionog sistema. Nakon 50 dana broj mikroorganizama koji degradiraju ugljovodonike povećan je 100 puta. Na osnovu promena u grupnom sastavu prosečna stopa biodegradacije tokom bioremedijacije je bila za alifatičnu frakciju 24 mg kg-1 po danu, za aromatičnu 6 mg kg-1 po danu i 3 mg kg-1 po danu za NSO-asfaltensku frakciju. U zasićenoj ugljovodoničnoj frakciji metodom GC-MS (SIM metod) analizirani su izoprenoidi pristan i fitan i policiklični molekuli steranskog i triterpanskog tipa. Tokom bioremedijacionog procesa došlo je do biodegradacije i smanjenja relativnih količina izoprenoida, sterana, tri- i tetracikličnih terpana i pentacikličnih 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