Effects of Purine Bases on Riboflavin Production by Eremothecium ashbyii

Abstract

Addition of purine bases into a growth medium involving glucose, peptone, yeast extract, salts and Tween 80 led to a conspicuous augment of riboflavin yield with Eremothecium ashbyii IFO 0944. The maximal yields with guanine, xanthine, adenine and hypoxanthine were revealed at the concentrations of 1.50,1.70,1.75 and 2.0mM, respectively. In a complete medium consisting of glucose, asparagine, salts and vitamins (inositol, thiamine and biotin) riboflavin synthesis was stimulated by supply with guanine, xanthine or hypoxanthine, but not with adenine. Guanine and xanthine were most effective to increase riboflavin synthesis. However, when Tween 80 was present in the medium, addition of guanine or hypoxanthine caused an inhibition of riboflavin production, while addition of xanthine did not affect the production.