During fermentation of classical (12%), HG (15%) and VHG wort (18%) physiological state of brewing yeasts (Safale US-05 and Safbrew T-58) was observed. After innoculation and during selected moments of wort fermentation the following features were examined: biomass concentration, yeast cell size, contribution of budding cells, magnesium ion concentration. The Safale US-05 beter adapted to the high concentration of wort. These yeasts produced more biomass, budded for a longer time of fermentation and maintained the cell size on the constant level. The secretion of magnesium ions into the wort in the beginning of fermentation showed also the good condition of these yeasts.

Protein engineering is now a very important sector in modern biotechnology. They are used random mutagenesis, which allows production enzymes and proteins with the desired characteristics or increased activity. These techniques and the appropriate method of bacterial selection permit to accelerate the evolution of genomes for industry. There are many techniques to create random changes in the amino acid sequence of the protein. This can be achieved by treating the whole bacteria or DNA chemicals or UV radiation, using modified techniques of PCR or RCA in error-prone mix, mutator strains and using one of the methods of DNA shuffling. The following article provides a description of these methods and examples of successful use of them.

The presented research was to assess the level of lytic enzymes biosynthesis by Trichoderma strains in the presence of Yarrowia lipolytica yeast biomass. Two strains of filamentous fungi: Trichoderma harzianum T33 and T. citrinoviride C1, as well as two strains of yeast Yarrowia lipolytica: 8665 UV’s and Y. lipolytica A101 were used. Grown-up Yarrowia biomass were inoculated with filamentous fungi spores and cultivated in the same time (during 8-days). The assessment of the outcoming culture fluids included the activity of lytic enzymes: chitinases, laminarinases and lichenases, and the level of extracellular proteins. The concentration of released proteins in most variants was low, however, for thermally inactivated Yarrowia biomass it reached best results (170–210 mg×ml^-1). In most cases the presence of yeasts biomass had a positive effect on the the efficiency of lytic enzymes biosynthesis.