The ability of the isolates to grow in the presence of phytate as a
unique phosphate source was tested on solid and liquid media as described
by Nuobariene et al. (2011). Briefly, three different defined
media were prepared: Delft Phy, a medium containing phytic acid
dipotassium salt (1850 mg/l; Sigma P5681) as a unique phosphate
source, Delft+, a medium containing phosphate (3510 mg/l) but no
phytate, used as positive control, and Delft−, a phosphate-free medium,
used as negative control. The protocols for preparation and composition
of each medium were reported by Nuobariene et al. (2011). Few
yeast colonies were inoculated in 10 ml sterile YPD medium and cultivated
overnight in a water bath at 30 °C with shaking (170 rpm/min).
Yeasts cultures, OD600 level set at 0.1, were transferred in 50 ml