Isolation of a new acid- and salt-tolerant yeast capable of fermenting
ethanol from xylose Water samples (10 ml) collected from rivers (about pH
2.0) flowing through the area of Kusatsu hot spring were mixed with acid GMS
medium (pH 2.5, 10 ml) containing 2.5% sodium sulfate, and incubated at 30C for
1 week. One milliliter of the culture was transferred into acid XMS medium (pH 2.5,
10 ml) containing 2.5% sodium sulfate, and was incubated at 30C for 1 week. This
transfer operation to acid XMS mediumwas repeated 5 times. Appropriately diluted
cultures were spread on plates of the acid XMS agar medium and incubated at 30C
for 1 week. Colonies picked up from the plates were incubated in the liquid acid XMS
medium (1.0 ml) using 96-well microplates over the course of 1 week. The
concentration of ethanol was analyzed using an alcohol densitometer (Alcomate
AL-2, Riken Keiki, Tokyo).