Chemistry: molecular biology and microbiology – Treatment of micro-organisms or enzymes with electrical or... – Modification of viruses
Patent
1991-05-02
1993-06-08
Lilling, Herbert J.
Chemistry: molecular biology and microbiology
Treatment of micro-organisms or enzymes with electrical or...
Modification of viruses
435114, 435244, 435245, 435255, 435911, 4351731, C12N 1500, C12N 116, C12P 1310
Patent
active
052178889
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to yeast capable of accumulating L-arginine in the cells in large quantities. The yeast cells of the present invention are expected to be utilized as feed for livestock.
BACKGROUND ART
Heretofore yeast cells such as Torula yeast and beer yeast have been utilized as feed for livestock.
However, some livestock cannot be sufficiently supplied with some amino acids from yeast cell source alone. For example, domestic fowls tend to suffer from insufficiency of L-arginine. Insufficient amino acids are supplemented by addition of each amino acid, but this is not economically advantageous. If various kinds of yeasts are provided which are capable of accumulating insufficient amino acids in the cells in large quantities, the yeast cells would be widely utilized as feed for livestock.
As yeast capable of accumulating L-arginine in the cells in large quantities, there is known a regulatory mutant (argR, cpoO) belonging to the genus Saccharomyces which accumulates 1.7% of L-arginine in the cells [Eur. J. Biochem., 12, No. 1, 40-47 (1970)].
DISCLOSURE OF THE INVENTION
According to the present invention, ethionine-resistant strains belonging to the genus Kluyveromyces can be provided as yeast capable of accumulating L-arginine in the cells in large quantities. These strains are yeasts with a high arginine content which contain at least 5% (on a dry cell weight basis) of free L-arginine in the cells.
The yeast with a high arginine content of the present invention includes any yeast which belongs to Kluyveromyces polysporus and has resistance to ethionine. Yeast having such properties can be obtained by using yeast belonging to the genus Kluyveromyces as a parent strain, and subjecting the strain to a conventional mutation treatment, for example, UV irradiating or a chemical treatment with N-methyl-N'-nitro-N-nitrosoguanidine, etc. and selecting yeast capable of accumulating at least 5% (on a dry cell weight basis) of L-arginine in the cells from mutants which have acquired resistance to ethionine. Any yeast may be usable as the parent strain so long as it belongs to the genus Kluyveromyces. A specific example is Kluyveromyces polysporus IFO 0996 [Int. J. Syst. Bact., 38, 822 (1983)].
The process for obtaining the yeast with a high arginine content of the present invention is described specifically below.
As the parent strain, Kluyveromyces polysporus IFO 0996 was used. Cells of the parent strain were suspended in a physiological saline solution to a density of 10.sup.8 cells/ml. The suspension (0.1 ml) was smeared on a minimum agar medium [20 g/l glucose, 6.7 g/l Yeast Nitrogen Base (manufactured by Difco), 20 g/l agar; pH 5-6] containing 1000 .mu.g/ml ethionine. The plate was put under a UV light source (15 W ultraviolet lamp, wavelength; 253.ANG.) at a distance of 35 cm from the light source and exposed to UV rays for 20 seconds. The agar plate irradiated with UV rays was incubated at 30.degree. C. for 2-4 days. About 250 colonies of ethionine-resistant strains grew on the surface of the ethionine-containing medium. Two hundred ethionine-resistant strains were picked up and cultured in a manner similar to Example 1 described below. Some ten strains which accumulated more than 5.0% of L-arginine in the cells were selected. One of them was named Kluyveromyces polysporus ETA82-33 and was deposited with the Fermentation Research Institute, Agency of Industrial Science and Technology, Japan as FERM BP-2560 on Aug. 22, 1989, under the Budapest Treaty.
As the medium for culturing the yeast with a high arginine content of the present invention, there may be used a nutrient medium or a synthetic medium containing carbon sources, nitrogen sources, inorganic salts, growth factors, etc.
As the carbon source, any carbohydrates such as glucose, fructose, sucrose, molasses, starch, starch hydrolyzate and fruit juice, alcohols such as ethanol, methanol and propanol, etc. may be used so long as the yeast can assimilate them.
As the nitrogen source, ammonium sulfate, ammonium nitrate,
REFERENCES:
patent: 3801456 (1974-04-01), Kubota et al.
patent: 3833473 (1974-09-01), Kubota et al.
patent: 3887435 (1975-06-01), Nakamura et al.
patent: 4439525 (1984-03-01), Shay et al.
patent: 4463094 (1984-07-01), Chibata et al.
patent: 4582801 (1986-04-01), Hamada et al.
ATCC "Catalogue of Fungi/Yeasts" 17th Edition 1987 Jong et al. Editors pp. 198-200 Rockville, Maryland.
APS JPOABS J59:151894 Hino et al. Aug. 30, 1984.
APS JPOABS J59:55194 Nakamura Mar. 30, 1984.
Eur. J. Biochem. 12 No. 1 (1970), F. Ramos, P. Thuriaux, J. M. Wiame and J. Bechet "The Participation of Ornithine and Citrulline in the Regulation of Arginine Metabolism in Saccharomyces cerevisiae" pp. 40-47.
Chemical Abstracts, vol. 98, No. 13, Mar. 28, 1983, Columbus, Ohio, Abstract No. 104060J, Sawnor-Korszynska Danuta et al.; `Secondary Effects of the Ethionine-resistance mutation in Saccharomycopsis Lipolytica.`, p. 332, col. L, & Acta Biochim, Pol. vol. 29, No. 1-2, 1982, pp. 151-157.
Hara Takahiro
Ishino Shuichi
Teshiba Sadao
Kyowa Hakko Kogyo Co. Ltd.
Lilling Herbert J.
LandOfFree
Yeast with high content of arginine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Yeast with high content of arginine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Yeast with high content of arginine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1933372