Abstract
All of six strains of Candida robusta isolated from fruits produced larger amounts of riboflavin in acetate medium than in sucrose medium. Strain No. 6 was selected as the best one for its production. Two type cultures of this species, however, did not produce any riboflavin in either medium. The riboflavin-producing ability may not necessarily be, therefore, a general property of C. robusta. Candida guilliermondii gave riboflavin in a small yield in sucrose medium, but did not produce it in acetate medium.
Ammonium salts and urea, as well as organic nitrogen sources such as amino acids, asparagine and peptone, which were unsuitable in sucrose medium, favored riboflavin production by C. robusta in acetate medium. Apparently no flavinogenic factor was necessary for this yeast.
