To study the tannin tolerance of yeast isolates, YMA was separately
prepared from a tannin solution before being autoclaved at 121 °C for
15 min. Tannin was dissolved in a 0.1 M Sodium phosphate buffer
with a pH of 7.0 and filtered through a 0.2-μm filter cartridge. The sterile
tannin solution was aseptically pipetted into the melted YMA to final
concentrations of 10 g/l, 20, g/l, 30 g/l, 40 g/l and 50 g/l tannin before
being used. A single colony of each yeast isolate was picked up and
spiked on YMA with and without sterile tannin supplementation using
a toothpick. Growth of yeast isolates was observed after incubation at
30 °C for up to 7 days.