The Characteristics of Uricase Production by a Hyphomycetes isolated from the Excrements of Cettia diphone cantans. IV. Effect of Amino Acids as Nutritional Substances

In order to find the optimal medium composition for the induction and production of uricase by the F1 strain, a fungus isolated from the feces of a Japanese nightingale (Cettia diphone), effect of nitrogen source was examined. Twenty-two kinds of amino acid were examined in a medium containing Casamino acid. Then, serine, aspartic acid, glycine, glutamic acid, proline, and asparagine, found to be most effective for the mold growth and uricase production, were examined for uricase production in a medium not sontaining Casamino acid. Preliminary experiments had shown that Casamino acid is the most suitable nitrogen source for the growth of F1 strain and none of the amino acids tested was found to be more effective than Casamino acid for speciftc uricase production, although serine showed about the same effect as Casamino acid. While asparagine accelerated the growth of this fungus, it acted inhibitory for the enzyme production and this was found to be due to the marked inhibition of the incorporation of urate by the fungus in the asparagine medium. It was proved that the effect of Casamino acid for fungal growth and enzyme production was the consorted action of componental amino acids and that its optimal concentration was about 1.0%. The characteristic of Casamino acid was found to be a more efficient production of the enzyme than single amino acid and this was due to the marked effect of Casamino acid in shortening the induction period of growth.