Abstract: An object of the present invention is to provide a novel method for producing L-cysteine in place of a conventional fermentation method. More specifically, the object is to provide a method for producing L-cysteine by the combination of heat-resistant enzymes. In particular, the object is to provide a method for efficiently producing a pathway for synthesizing O-phosphoserine from 3-phosphoglyceric acid (3PG) via phosphohydroxypyruvic acid (HPV). The present invention solved the problem by a method for producing O-phosphoserine including acting phosphoserine aminotransferase (PSAT) and 3-phosphoglycerate dehydrogenase (PGDH) that are each derived from a thermophilic bacterium on 3PG to generate O-phosphoserine, and a method for producing L-cysteine including the step described above.

Abstract: A natural yeast extract which is rich in glutamic acid and therefore has an impact at first taste. Further, provided is a yeast extract which is also rich in 5?-guanylic acid or 5?-inosinic acid and therefore has strong umami. Further, provided is a yeast mutant capable of accumulating a large amount of glutamic acid, glutamine and ribonucleic acid for obtaining such a yeast extract. A yeast mutant to which resistance to organic acids and analogues thereof has been imparted by inducing spontaneous mutation, accumulates a significant amount, i.e., 10% by weight or more of the total of free glutamic acid and glutamine in the cell, and further accumulates 5% by weight or more of a ribonucleic acid. The yeast extract produced by using this strain contains 20% by weight or more of L-glutamic acid, and further contains 3% by weight or more of 5?-IG.

Abstract: A natural yeast extract which is rich in glutamic acid and therefore has an impact at first taste. Further, provided is a yeast extract which is also rich in 5?-guanylic acid or 5?-inosinic acid and therefore has strong umami. Further, provided is a yeast mutant capable of accumulating a large amount of glutamic acid, glutamine and ribonucleic acid for obtaining such a yeast extract. A yeast mutant to which resistance to organic acids and analogues thereof has been imparted by inducing spontaneous mutation, accumulates a significant amount, i.e., 10% by weight or more of the total of free glutamic acid and glutamine in the cell, and further accumulates 5% by weight or more of a ribonucleic acid. The yeast extract produced by using this strain contains 20% by weight or more of L-glutamic acid, and further contains 3% by weight or more of 5?-IG.

Abstract: 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.

Abstract: A natural yeast extract which is rich in glutamic acid and therefore has an impact at first taste. Further, provided is a yeast extract which is also rich in 5?-guanylic acid or 5?-inosinic acid and therefore has strong umami. Further, provided is a yeast mutant capable of accumulating a large amount of glutamic acid, glutamine and ribonucleic acid for obtaining such a yeast extract. A yeast mutant to which resistance to organic acids and analogues thereof has been imparted by inducing spontaneous mutation, accumulates a significant amount, i.e., 10% by weight or more of the total of free glutamic acid and glutamine in the cell, and further accumulates 5% by weight or more of a ribonucleic acid. The yeast extract produced by using this strain contains 20% by weight or more of L-glutamic acid, and further contains 3% by weight or more of 5?-IG.

Abstract: An object of the present invention is to provide a multifunctional gel material including a gel and solid materials, in which the solid materials are moderately dispersed within the gel by adjusting the specific gravities of the gel and the solid materials, or in which the solid materials are always arranged in the same predetermined positions within the gel by dispersing them to the predetermined positions with a positioning means. To achieve this object, the solid materials are dispersed within the gel by using any means. Specifically, the solid materials are dispersed within the gel by adjusting the specific gravity of the solid materials with the specific gravity of the gel. Furthermore, the solid materials are moderately dispersed within the gel by being appropriately arranged by a positioning means.