The P. membranaefaciens yeast strain was obtained from the
Chinese General Microbiological Culture Collection Center, Beijing,
China. The yeast culture was maintained at 4 C on nutrient yeast
dextrose agar (NYDA) medium containing 8 g of nutrient broth, 5 g
of yeast extract, 10 g of glucose, and 20 g of agar in 1 L of distilled
water. The yeast was transferred from NYDA to nutrient yeast
dextrose broth