Stable antimicrobial nisin layers were prepared on the carrying medium-polyvinyl alcohol (PVA) films, crosslinked by glutaric acid. Surface plasma dielectric coplanar surface barrier discharge (DCSBD) modification of polyvinyl alcohol was used to improve the hydrophilic properties and to provide better adhesion of biologically active peptide-nisin to the polymer. The surface modification of films was studied in correlation to their cross-linking degree. Nisin was attached directly from the salt solution of the commercial product. In order to achieve a stable layer, the initial nisin concentration and the following release were investigated using chromatographic methods. The uniformity and stability of the layers was evaluated by means of zeta potential measurements, and for the surface changes of hydrophilic character, the water contact angle measurements were provided. The nisin long-term stability on the PVA films was confirmed by tricine polyacrylamide gel electrophoresis (SDS-PAGE) and by antimicrobial assay. It was found that PVA can serve as a suitable carrying medium for nisin with tunable properties by plasma treatment and crosslinking degree.

No abstract

This work describes novel alternative for extraction of bacteriocin nisin from a whey fermentation media and its stabilization by using polyethylene glycol as matrix with high practical applicability. This product was compared with commercially available nisin product stabilized by sodium chloride and nisin extracted and stabilized by using ammonium sulfate and polysorbate 80.The stability of samples was tested by means of long-term storage at −18, 4, 25, and 55 ∘ C up to 165 days. The nisin content in the samples was determined by high-performance liquid chromatography and electrophoresis. In addition, effect of whey fortification with lactose on nisin production and antibacterial activity studied against Staphylococcus aureus was tested. Results show that stabilization by polyethylene glycol provides enhanced nisin activity at 55 ∘ C after 14 days and long-term stability at 25 ∘ C with keeping antibacterial activity.

No abstract

Our work deals with the identification of the intensive spectral lines and bands measured during the plasma deposition using the hexamethyldisiloxane (HMDSO) and the tetravinylsilane (TVS) as monomer. The deposition processes were carried out in a continual regime as well as in a pulsed regime with the varied relative pulse duration. At first, the pure monomers were used.Furthermore, tetravinylsilane was mixed in various ratios with oxygen, the CH 4 +H 2 gas mixture was added to hexamethyldisiloxane. We observed a lot of changes in intensity and character of spectra with increasing pulse duration, with increasing oxygen flow rate. Oxygen has an important role for the creation of various fragments and cyclic oligomers.In the next part of experiment, exhaust gas was investigated by gas-chromatography and mass spectrometry (GC-MS). Oligomers with complex structure were identified.PACS: 52.70.Kz