Patents by Inventor Waikei Tsang

Waikei Tsang 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).

  • Two-step enzyme method for preparing 7-aminocephalosporanic acid
    Patent number: 8003358
    Abstract: The present invention discloses a two-step enzyme method for preparing 7-aminocephalosporanic acid from cephalosporin C, wherein D-amino acid oxidase used is purified D-amino acid oxidase mutant of yeast Trigonopsis variabilis, having a specific activity of 105% higher than that of parent D-amino acid oxidase. The method has no need of addition of hydrogen peroxide, ?-lactamase inhibitor, catalase inhibitor, catalase and the like commonly used in the prior art. The productivity of the method can reach more than 93%. Thus, the method is simple, low in cost and high in productivity.
    Type: Grant
    Filed: August 2, 2006
    Date of Patent: August 23, 2011
    Assignee: Bioright Worldwide Company Limited
    Inventors: Jun Wang, Waikei Tsang, Hongkin Yap, Junmin Chen, Yaulung Siu, Supyin Tsang
  • Two-Step Enzyme Method for Preparing 7-Aminocephalosporanic Acid
    Publication number: 20100112633
    Abstract: The present invention discloses a two-step enzyme method for preparing 7-aminocephalosporanic acid from cephalosporin C, wherein D-amino acid oxidase used is purified D-amino acid oxidase mutant of yeast Trigonopsis variabilis, having a specific activity of 105% higher than that of parent D-amino acid oxidase. The method has no need of addition of hydrogen peroxide, ?-lactamase inhibitor, catalase inhibitor, catalase and the like commonly used in the prior art. The productivity of the method can reach more than 93%. Thus, the method is simple, low in cost and high in productivity.
    Type: Application
    Filed: August 2, 2006
    Publication date: May 6, 2010
    Inventors: Jun Wang, Waikei Tsang, Hongkin Yap, Junmin Chen, Yaulung Siu, Supyin Tsang
  • Recombinant D-amino acid oxidases
    Patent number: 7517677
    Abstract: The present invention discloses two novel D-amino acid oxidases, whose activities of converting cephalosporin C to glutaryl-7-aminocephalosporanic acid are at least 25% higher than that of wild-type Trigonopsis variabilis D-amino acid oxidase and the encoding DNA sequences thereof.
    Type: Grant
    Filed: April 12, 2004
    Date of Patent: April 14, 2009
    Inventors: Jun Wang, Hongkin Yap, Waikei Tsang, Yuksun Lui, Yaulung Philip Siu, Supyin Tsang, Minghon Yau
  • Recombinant D-Amino Acid Oxidases
    Publication number: 20080009052
    Abstract: The present invention discloses two novel D-amino acid oxidases, whose activities of converting cephalosporin C to glutaryl-7-aminocephalosporanic acid are at least 25% higher than that of wild-type Trigonopsis variabilis D-amino acid oxidase and the encoding DNA sequences thereof.
    Type: Application
    Filed: April 12, 2004
    Publication date: January 10, 2008
    Inventors: Jun Wang, Hongkin Yap, Waikei Tsang, Yuksun Lui, Yaulung Siu, Supyin Tsang, Minghon Yau