Highly efficient ethanol-fermentative yeast

A highly efficient ethanol-fermentative yeast, the fermentative yeast effectively producing ethanol from pentose and hexose,

• wherein the fermentative yeast has xylose utilization and ethanol fermentation performance improved, in comparison with a wild strain of Meyerozyma guilliermondii, by performing habituation of the wild strain of Meyerozyma guilliermondii in culture in a medium in which a mutagen is added to an enzymatically saccharified liquid derived from rice straw treated with ammonia, the mutagen including any one of an ethylating agent, a base analog and a nitroso compound, and selecting yeasts growing in the medium and
• wherein the fermentative yeast is deposited to National Institute of Technology and Evaluation (NITE) Patent Microorganisms Depositary under the accession number NITE BP-01962.