Patents by Inventor Katsuo Iizumi

Katsuo Iizumi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Method for producing L-3,4-dihydroxyphenylalanine by precipitation of anhydrous crystals
    Patent number: 5518905
    Abstract: A method for producing L-3,4-dihydroxyphenylalanine comprising contacting microorganism cells having .beta.-tyrosinase activity with catechol, pyruvic acid and ammonium ion or with catechol and L-serine, at a temperature lower than 25.degree. C. in the presence of anhydrous crystals of L-3,4-dihydroxyphenylalanine. L-3,4-dihydroxyphenylalanine formed from said contacting precipitates as anhydrous crystals in the reaction mixture, and the thus-precipitated anhydrous crystals can be collected. According to the method of the present invention, crude crystals of L-3,4-dihydroxyphenylalanine having a high purity may be obtained at a high yield of recovery.
    Type: Grant
    Filed: July 28, 1994
    Date of Patent: May 21, 1996
    Assignee: Ajinomoto Co., Inc.
    Inventors: Takuya Kotani, Katsuo Iizumi, Makoto Takeuchi
  • Method for increasing beta-tyrosinase activity in Erwinia herbicola
    Patent number: 5368981
    Abstract: A method for increasing .beta.-tyrosinase activity in Erwinia herbicola is disclosed. The activity is increased by culturing the microorganism until it reaches stationary phase and maintaining the stationary phase for a period of 6 to 24 hours while maintaining the pH between 7.0 and 8.3.
    Type: Grant
    Filed: January 26, 1994
    Date of Patent: November 29, 1994
    Assignee: Ajinomoto Co., Inc.
    Inventors: Takayasu Tsuchida, Yoshitaka Nishimoto, Takuya Kotani, Katsuo Iizumi
  • Method for producing L-3, 4-dihydroxyphenyalanine by Erwinia having tyrosinase activity
    Patent number: 5338672
    Abstract: The present invention relates to improved methods for producing L-3, 4-dihydroxyphenylalanine from catechol, pyruvic acid and ammonium ion, or catechol and L-serine, by utilizing .beta.-tyrosinase activity of a microorganism which belongs to the genus Erwinia. According to the method of the present invention, L-3,4-dihydroxyphenylalanine can be produced at a lower cost and higher efficiency as compared with that in the conventional method.
    Type: Grant
    Filed: March 24, 1993
    Date of Patent: August 16, 1994
    Assignee: Ajinomoto Co., Inc.
    Inventors: Takayasu Tsuchida, Yoshitaka Nishimoto, Takuya Kotani, Katsuo Iizumi
  • Anhydrous L-lysine monohydrochloride in .alpha.-cyrstalline form and preparation thereof
    Patent number: 4256917
    Abstract: A novel crystalline form of anhydrous L-lysine monohydrochloride has been found. The novel crystals do not become agglomerated or hardened when packaged. The crystals are formed when the corresponding dihydrate crystals having a sodium content equal to or less than 4 ppm* are dried in a chamber maintained at a temperature equal to or greater than 115.degree. C.*Na/L-Lys.
    Type: Grant
    Filed: December 10, 1976
    Date of Patent: March 17, 1981
    Assignee: Ajinomoto Company, Limited
    Inventors: Yoshikazu Takayanagi, Katsuo Iizumi, Masashi Miyazawa, Nobuyuki Yamaya, Hajime Tamura