In this study glycerol was used as a carbon source for the production of C. utilis biomass in monoculture and in mixed culture with G. oxydans. Yeast culture was performed in control media as well as growth media with glycerol concentration 30 gL^-1. It also has been checked if dihydroxyacetone (DHA) can be used as a carbon source for C. utilis for biomass production. For this purpose yeast were cultivated with acetic bacetria (mixed culture) in growth media. Acetic bacteria are able to oxidate glycerol to DHA. During the cultivation optical density and biomass yield were measured. The highest increase of yeast biomass was observed in the control media after 24 hours and it was 15.8 g dry matter per L. After 48 hours of C. utilis culture in media contains glycerol (30 gL^-1) the yield was 11,4 g d.m.L^-1, while in mixed culture it was 12.5 g d.m.L^-1. The highest yield of C. utilis biomass in media consist 2% of DHA was 2.7 g d.m.L^-1 after 48 hours. The experiment has shown that DHA is not a easily assimilable carbon source for C. utilis.

The aim of this text, was validation of microbiological quality of homemade beer – presence and infected of lactic acid bacteria with using microbiological analyzer BacTrac 4300. Verified that, product brewed at home are stabile from the viewpoint of microbiology and long store time had no impact of microorganism strength. Good level of microbiological quality in homemade beer, influence to no organoleptic changes during storage. Though observed that long storing lead gushing phenomenon short time after open the bottle – effect of yeast autolysis. Concluded that in home, are possibly preparing well quality beer with unique organoleptic properties, but necessary is basic knowledge of brewing, know how and microbiology rules.

The invertase positive Yarrowia lipolytica A-101-B56-5 strain was analyzed for simultaneous production of citric acid (CA) and invertase in four media of different composition. The analysis was carried out as bioreactor batch cultures with sucrose as carbon source. The highest CA concentration (157 g/L) was noted in medium A (250 g sucrose, 7.50 g NH₄Cl, 0.10 g KH₂PO₄, 5.00 g MgSO₄×7H₂O and 3.0 g yeast extract in 1 L). The yield of CA from consumed substrate reached 0.698 g/g, the volumetric productivity was 0.785 g/L/h and the specific production rate reached 0.018 g/g/h. In terms of invertase biosynthesis, the best medium was the rich medium D (150 g sucrose, 3.0 g yeast extract, 5.0 g malt extract and 5.0 g peptone in 1 L). The total invertase activity obtained in this medium reached 124 000 U/L. The final CA concentration in this medium was lower than in medium A, however, it presented the highest volumetric productivity (1.281 g/L/h), specific production rate (0.065 g/g/h) as well as the highest yield from biomass (4.704 g/g). This culture was also the shortest (72 h) among all tested processes. Surprisingly, the highest amount of secreted invertase (48.7%), calculated from the total invertase activity, was obtained for the process in medium A, and was six times higher than in the other media. This phenomenon was dependent on sucrose concentration, the accumulated biomass and the osmotic pressure of the medium.