The aim of the present study was to compare the influence of the seed culture medium (YNB or mineral) and the sort of corn steep (liquor or powder) on the biosynthesis of pyruvic and α-ketoglutaric acids from crude glycerol by Yarrowia lipolytica A-10 strain. Batch cultures were carried out until the substrate exhaustion (100 g∙dm^-3 of glycerol) and lasted 68–118 h. Yeast produced from 30.4 to 35.8 g∙dm^-3 of pyruvic acid and from 14.4 to 17.9 g∙dm^-3 of α-ketoglutaric acid. Higher values of volumetric production rate of both acids were achieved when YNB was used as a seed culture medium. The yield of ketoglutaric acid production was similar in all culture variants. However, for pyruvic acid the highest value of this parameter (0,35 g∙g^-1) was obtained when mineral medium and corn steep liquor were used. The highest percentage of protein, about 38%, was determined in yeast biomass derived after the culture with mineral seed culture medium.

1,3-propanediol (1,3-PD) is the important product used in chemical industry. Microbiological synthesis of 1,3-PD from crude glycerol is a good solution, both from an economic and environmental point of view. The aim of this work was to investigate the effect of raw material (pure and crude glycerol) on the efficiency of the synthesis of 1,3-PD by the bacteria Clostridium butyricum DSP1 and Clostridium butyricum DO14 isolated from the samples taken from natural environment. Two strains of C. butyricum were simultaneously investigated. The obtained results showed that the concentration of 1,3-PD was slightly lower in the case of crude glycerol than in pure glycerol, for both strains. Moreover, waste glycerol was not completely utilized.

Twenty-four mutants in strain Yarrowia lipolytica Wratislavia K1 were obtained after mutagenesis induced by UV irradiation. The selection, on the basis of the growth ability on YNB medium containing erythritol, indicated nine strains with the size of colony surface similar to parent strain. In the 7-day shake-flasks experiment, in glycerol media, yeast produced from 10.3 to 16.6 g^.dm^-3 of erythritol and from 11.5 to 17.9 g^.dm^-3 of mannitol. For further studies in bioreactor cultures strains K1-UV20 and K1-UV21 were chosen. The highest concentration of erythritol was obtained by strain K1-UV21 on crude glycerol medium, where 78.7 g^.dm^-3 of erythritol was produced corresponding to 0.49 g·g^-1 yield and 0.68 g^.dm^-3h^-1 volumetric productivity. The analysis of philogenetic similarity of based on RAPD-PCR method showed high similarity of the mutant strain Wratislavia K1-UV21 to parental strains of Y. lipolytica.