[Culture conditions for uricase formation of Candida utilis]

Abstract

A uricase producing strain, Candida utilis AS 2.117, was screened out and the uricase-forming conditions have been investigated. The results are obtained as follows: uric acid, xanthine and guanine were found to be effective inducers for enzyme formation. Corn steep liquor was essential for enzyme formation and cell growth. Sucrose, glucose, D-mannose and D-fructose were the suitable carbon sources for enzyme formation. To the medium containing corn steep liquor, addition of inorganic nitrogen sources was harmful to the enzyme formation, however, addition of organic nitrogen sources enhanced enzyme activity slightly. The suitable medium for uricase formation was consisted of sucrose 5%, corn steep liquor 3%, uric acid 0.1%, proteose-peptone 0.1%, biotin 0.05%, KCl 0.1%, NaCl 0.1% at pH 6.2. When the yeast was grown in 250 ml conic flask containing 30 ml of the medium mentioned above on the rotary shaker (200 r/min) at 25 degrees C for 21 h, uricase with 0.6 u/ml activity was obtained.