MATERIALS AND METHODS
Organisms I. orientalis MF-121, an acidesalt tolerant yeast, was isolated
from an acidic hot spring (11). Saccharomyces cerevisiae kyokai 7 was obtained
from the Brewing Society of Japan (Tokyo, Japan). S. cerevisiae NBRC 1953 and
Pichia stipitis NBRC 10063 were obtained from the NITE Biological Resource
Center (Chiba, Japan).