The laboratory mutant strain of baker yeast AF37X was used
throughout the experiments. The yeast strain was maintained in
MY medium whose composition (in g l−1
) was glucose, 20; yeast
extract, 3; polypeptone, 5; malt extract, 3; agar, 20. In all cases,
cultures were maintained at 37 °C for 24 h and then stored at 4 °C.
Subculturing was done every two months. The composition of the
pre-culture medium for yeast (in g l−1
) was: glucose, 10; sucrose, 10;
yeast extract, 3; polypeptone, 5; malt extract, 3. All the media were
adjusted to pH 6.5 and autoclaved at 116 °C for 20 min before use.