Yeast mutant and yeast extract
The present invention provides a natural yeast extract having a high-impact first taste by containing glutamic acid in a large amount. Further, the present invention provides a yeast extract having strong umami by containing 5′-guanylic acid or 5′-inosinic acid in a large amount. In addition, the present invention provides a yeast mutant accumulating glutamic acid, glutamine, and ribonucleic acid in a large amount for obtaining the yeast extract. A yeast mutant inducing a natural mutation to which organic acid-tolerance or organic acid analogue-tolerance is imparted accumulates free glutamic acid and glutamine in such a significant amount as a total amount of 10% by weight or more in a cell, and further accumulates ribonucleic acid in an amount of 5% by weight or more. A yeast extract produced using the above yeast mutant contains L-glutamic acid in an amount of 20% by weight or more, and further contains 5′-IG in an amount of 3% by weight or more.
1. A yeast mutant of Candida utilis , wherein:
the yeast mutant is Candida utilis 36D61, accession number: FERM BP-11103;
free glutamic acid and glutamine are accumulated in a total amount of 10% or more, based on a total dry cell weight;
ribonucleic acid (RNA) is accumulated in an amount of 5% or more, based on the total dry cell weight; and
the yeast mutant is tolerant to ethyl bromopyruvate and 2-oxoglutaric acid.