TRANSFORMANT OF YEAST OF GENUS SCHIZOSACCHAROMYCES, METHOD FOR PRODUCING SAME, METHOD FOR PRODUCING ß-GLUCOSIDASE, AND CELLULOSE DEGRADATION METHOD

摘要

To provide a transformant of a yeast of the genus Schizosaccharomyces which can produce a modified-type β-glucosidase with improved glucosidase activity, a method for producing such a transformant, a method for producing the modified-type β-glucosidase, and a cellulose degradation method using the modified-type β-glucosidase. A transformant of a yeast of the genus Schizosaccharomyces characterized by having a structural gene sequence comprising a region encoding a modified-type β-glucosidase which is obtained by introducing at least one mutation selected from the group consisting of specific mutations into a β-glucosidase derived from a filamentous fungus, and a promoter sequence and a terminator sequence for expressing the structural gene in a chromosome, or alternatively by having the sequences as an extrachromosomal gene, and is characterized in that the modified-type β-glucosidase has higher thermostability or higher resistance to glucose inhibition than a β-glucosidase which does not have the specific mutations.

主权项

1. A transformant of a yeast of the genus Schizosaccharomyces characterized by having a structural gene sequence comprising a region encoding the following modified-type β-glucosidase, and a promoter sequence and a terminator sequence for expressing the structural gene in a chromosome, or alternatively by having the sequences as an extrachromosomal gene.
Modified-type β-glucosidase: A β-glucosidase derived from a filamentous fungus having at least one mutation selected from the group consisting of the following mutations 1 to 6, and has higher thermostability or higher resistance to glucose inhibition than a β-glucosidase which does not have the mutations. Mutation 1; a mutation in which an amino acid corresponds to isoleucine at position 244 of AaBGL1 (BGL1 of Aspergillus aculeatus) is substituted by phenylalanine. Mutation 2; a mutation in which an amino acid corresponds to glycine at position 282 of AaBGL1 is substituted by phenylalanine. Mutation 3; a mutation in which an amino acid corresponds to asparagine at position 442 of AaBGL1 is substituted by serine. Mutation 4; a mutation in which an amino acid corresponds to glycine at position 452 of AaBGL1 is substituted by serine. Mutation 5; a mutation in which an amino acid corresponds to valine at position 503 of AaBGL1 is substituted by alanine. Mutation 6; a mutation in which an amino acid corresponds to arginine at position 613 of AaBGL1 is substituted by leucine.