The Characteristics of Uricase Production by a Hyphomycetes isolated from the Excrements of Cettia diphone cantans.V. Uricase Production by Pellicle in Various Growing Stages

A strain of Scopulariopsis brevicaulis was cultured in a nutrient medium (primary culture) and the culture medium was changed with a medium consisting of uric acid and dipotassium hydrogen phosphate at various stages of growth (logarithmic, stationary, and autolytic) to continue cultivation (secondary culture). In the primary culture, maximum formation of uricase was found in the latter part of the logarithmic stage. In the secondary culture, almost constant uricase activity was seen after 24-48 hr of culture, irrespective of the amount of uricase present during the stage of fungal growth and before the start of secondary culture. In the cells of the logarithmic stage, this constant value of uricase activity was reached after 6 hr, indicating a significantly rapid adaptation of the cells in this stage to induction and formation of uricase, compared to cells in other stages of growth. Thus, difference in induction and formation of uricase according to different growth stages appeared markedly. The constant value of uricase activity found in the secondary culture was not greater than that of the maximum value in primary culture. It was concluded from the present series of experiments that, in practice, uricase production by this strain will be more efficient by the primary culture as reported previously4) than by the use of a secondary culture as in this work.