Patent ID: 6551829
Filing Date: 2003-04-22
Classification: A21D,C12N,C12R

Abstract:
A method for producing a dry diploid baker's yeast of Saccharomyces cerevisiae comprising:a. producing a/&agr;-type diploid yeasts by mating an a-type haploid yeast with an &agr;-type haploid yeast to produce an a/&agr;-diploid yeast; b. selecting an a/&agr;-type diploid yeast from the a/&agr;-type diploid yeasts produced in step (a) by cultivating each yeast and by making bread using each yeast, and selecting the yeasts with the following characteristics: (i) primary points ability to grow in a blackstrap molasses medium; separability of the cultivated yeast from the medium; dehydration efficiency in forming the product of yeast; ability to maintain dough-expanding activity during long-term cold storage; resistance to softening of the yeast during long-term cold storage; ability of the yeast to maintain its color without absorbing the color of blackstrap molasses; and (ii) secondary point taste of bread produced with the yeast; c. disrupting the ATH1 genes of the same a-type and &agr;-type haploid yeasts used to produce the diploid yeast selected in step (b) by inserting a marker'selected from the group consisting of URA3, LYS2 and ADE2 into the respective ATH1 genes, wherein the respective NTH1 genes of the same a-type and &agr;-type haploid yeasts used to produce the diploid yeast selected in step (b) are not disrupted; d. mating the ATH1 gene-disrupted a-type haploid yeast obtained in step (c) with the ATH1 gene-disrupted alpha-type haploid yeast obtained in step (c) to produce an ATH1 gene-disrupted diploid yeast; e. culturing the ATH1 gene-disrupted a/&agr;-type diploid yeast obtained in step (d); f. recovering the cultured yeast; g. pressing the recovered yeast; and h. drying the pressed yeast by fluidized bed drying.