In the work, the usefulness of malt (6 variants) and rennet whey media (8 variants) for biomass production of 5 yeast strains, potential starter cultures for cheese making, before their preservation by freeze-drying, was studied. Growth media differed in the content of sugars, mineral compounds and growth factors. The growth of Candida kefyr PII1b and C. sphaerica FII7a yeast strains in both, malt- and whey-based media, was more dynamic than Yarrowia lipolytica JII1c, Y. lipolytica PII6a and C. famata MI1a. In case of malt media, the highest efficiency of biomass production was observed in broth enriched with mineral salts, containing nitrogen, phosphorus and sulphur, as well as yeast extract. In whey media, except mentioned above components, the addition of glucose was also indispensable. Yeast biomass obtained in those culture media revealed the highest level of viability after freeze-drying process (29,3–84,1%). In case of four from five tested yeast strains higher survival level was noticed for cells propagated in malt media than in whey media. Regardless of growth medium and applied protective agent, the highest viability (80%) in all preparations revealed Y. lipolytica JII1c strain.

The aim of the research was to examine the effect of mycotoxins OTA, ZEA and DAS on metabolism of free amino acids (FAN) and formation of selected volatile compounds during malt wort fermentation. Mycotoxins influenced on the bottom and top yeast strais in a differnt way. They disturbed FAN metabolism and caused some changes in sensory profile of fermented worts. As DAS concentration increased the yeast ability to FAN consumption as well as productivity of iso-butanol and amyl alcohols decreased. Among yeast strains used the S. carlsbergensis 13 and S. cerevisiae 46 were the most sensitive to mycotoxins. FAN utilization by these yeasts was very poor in the presence of DAS (15 μg∙ml^-1).

Aspergillus niger S culturing by the solid state method of fermentation was used for bioutilization of oilseed meal, the byproduct of biodiesel production, to oxalic acid synthesis. The amount of product calculated on substrate dry matter amounted to 150 g kg^-1. The bioprocess was characterized by high chemical selectivity as only oxalic acid was found in the post fermentation media. Moisture of the substrate in the range of 45 do 70% did not influence on the product concentration.

The aim of the study was to compare of aroma compounds profiles of experimental cheeses produced with Yarrowia lipolytica JII1c with those of commercial cheeses: Emmental, Gouda, Cheddar, Rokpol and Camembert. The level of yeast number as well as chemical composition and acidity were determined in all cheeses. Volatile aroma compounds were isolated from cheeses using solid phase microextraction (SPME) method and analysed by GC/MS method. The highest relative concentration of secondary alcohols, fatty acids and 3-indolo acetic acid were found in experimental cheese. The profile of aroma compounds of this cheese appeared to be similar to profiles of mould cheeses.