Ynb without amino acids

Escherichia coli strains were cultivated in LB medium according to standard protocols¹⁷ . Rich yeast extract peptone glucose (YPD) medium, containing 1% (w/v) yeast extract, 1% (w/v) peptone and 2% (w/v) glucose, was used to obtain yeast biomass for DNA extraction and inoculum preparation. Medium containing YNB without amino acids (Sigma-Aldrich) supplied with 2% (w/v) glucose was used for yeast inoculum preparation.
During shake-flask experiments the cultures were grown in 0.3 L baffled flasks containing 0.03 L or 0.05 L medium on a rotary shaker (CERTOMAT IS, Sartorius Stedim Biotech) at 28 °C and 240 rpm. Erythritol utilization rate was examined on medium containing YNB and 5% (w/v) or 10% (w/v) erythritol (YNB-e medium). Erythritol synthesis was conducted in Erythritol Synthesis Medium (ESM medium) containing 100 g/L glycerol (Chempur, Poland), 2.3 g/L (NH₄)₂SO₄ (Chempur), 1 g/L MgSO₄ × 7H₂O (Chempur), 0.23 g/L KH₂PO₄ (Chempur), 26.4 g/L NaCl (Chempur), 1 g/L yeast extract (Merck, Germany) and 3 g/L CaCO₃, pH 3.0. CaCO₃ was added separately to each flask after establishing pH 3 in order to prevent a fall of pH value.

Strains used in the study are the very closely related Y. lipolytica K1 [17 ] and Y. lipolytica MK1 [18 (link)], obtained from the Department of Biotechnology and Food Microbiology at Wrocław University of Environmental and Life Sciences. In strain K1 there is a point mutation, creating a stop codon at the beginning of the gene encoding Euf1 [12 (link)].
YPD liquid medium, consisting of 10 g/L yeast extract (Merck, Germany), 20 g/L glucose (Chempur, Poland), 20 g/L peptone (Merck, Germany), was used for inoculum preparation and storage. YPD strain cultures with 25% glycerol addition were stored at -80 °C. YNB without amino acids (Sigma-Aldrich, Germany) was a base for most of the liquid media used in the study and it was used in a concentration of 6.8 g/L. Carbon sources added to the YNB media were: glycerol (Wratislavia-Biodiesel), glucose (Chempur, Poland) or erythritol (Młyn Oliwski, Poland).

All C. albicans strains used in this study are listed in Table S3. Strains were routinely grown in YPD (20 g/liter glucose, 20 g/liter peptone, 10 g/liter yeast extract, with 20 g/liter agar if required) or SDG (synthetic defined glucose) minimal medium (20 g/liter glucose, 6.7 g/liter yeast nitrogen base [YNB] without amino acids; Sigma-Aldrich) at 37°C. For the induction of hyphal growth, strains were synchronized by two overnight incubations in SDG at 37°C. Cells (1 × 10⁶/ml) were then transferred to prewarmed SDG with 10% human serum (Sigma-Aldrich) and incubated at 37°C for the indicated times. If necessary, 50 μg/ml doxycycline (DOX) was added to the medium. For the medium shift, cells grown overnight in YPD at 30°C were diluted to 1 × 10⁶ cells/ml in prewarmed RPMI 1640 medium (Biochrom) or YPD and grown at 30°C (YPD) or 37°C (RPMI 1640). For the pH shift, overnight cultures of C. albicans strains grown in M199 medium (Sigma-Aldrich) (pH 4) were transferred to either M199 (pH 4) or M199 (pH 8) to reach a concentration of 1 × 10⁶ cells/ml and grown at 37°C.