Determination of the concentration and quality of DNA in the examined preparations is the first and fundamental act in studies of genetic material and is important in the further analysis. The result obtained has a decisive influence on the taking of further research. The aim of this study was to compare the quantity and quality (purity in terms of protein contamination, reagents for the isolation of cell particles and pollution) of DNA isolated from fresh chicken blood and kept using two commercial kits. The research material was the blood drawn from a vein v. basilica, fresh and stored for 24 months (frozen) at -20°C. Fresh and stored blood came from 10 individuals Polbar breed chickens. Stored blood came from 10 other individuals of the same race. Isolation of DNA was carried out based on two different sets of genomic DNA isolation: Genomic Midi AX, A & A Biotechnology and QIAamp DNA Blood Mini Kit. A statistically significant difference in concentration of different sets of DNA isolated isolation in fresh and kept blood. A better kit for isolation of DNA from chicken blood was putty Genomic Midi AX, a higher concentration of DNA obtained from fresh blood.

The bacterial colonization of solid material is a multi-step process. To define the rate of biofilm formation process on abiotic material under starvation, both morphology and extracellular polysaccharide (EPS) production must be accounted for. The aim of this study was to define the influence of limited nutrients availability in the medium on the morphological changes, the cell surface hydrophobicity and the synthesis of EPS by Pseudomonas aeruginosa. The relationship between the morphology of cells, the cell surface hydrophobicity, the EPS production and the P. aeruginosa biofilm development process on stainless steel surfaces (304L) was also examined. The cell surface area of P. aeruginosa was changed upon long-term starvation due to the decreasing the cell length. The change of P. aeruginosa morphology promoted the beginning stages of biofilm formation on the surface of stainless steel. The lower cell surface hydrophobicity indicated the extensive production of hydrophilic polysaccharides by examined bacteria under starvation. The synthesis of exopolysaccharide composed of glucose promoted more advanced stages of P. aeruginosa biofilm formation on the surface of stainless steel.

Yarrowia lipolytica are an nonconventional microorganisms able to assimilate organic compounds and produce extracellular enzymes. The current trend of their use is bioconversion of secondary metabolites (mainly citric acid) and aroma compounds (γ-lacton) and obtaining oleic cells used in fodder production. The microorganisms are characterized by high proteoand lipolytic activity. They are able to synthesize and secret extracellular proteases: serine (AEP) and aspartyl (AXP) and lipases (LIP1, LIP2 i LIP3). The expression of those enzymes is pH dependent and influenced also by the yeast growth phase and availability of carbon, nitrogen and sulfur sources. The recent years research points out many different possibilities of Y. lipolytica enzymes utilization. The easy way of their isolation combined with the use of food industry waste-products makes them an attractive and competitive product in comparison to commercially avaliable enzymes.