Studies on uricase induction in certain bacteria

Abstract

Three strains of Proteus vulgaris and two Streptomyces species were screened for inducible uricase formation. P. vulgaris (1753 and B-317-C), Streptomyces graminofaciens and S.albidoflavus showed inducible uricase activity, but P. vulgaris U7 did not show activity under the experimental conditions tested. Different amounts of constitutive and induced uricase were obtained by the four organisms using different culture media. The enzyme was induced in the producing organisms by different concentrations of different inducers, and uric acid was the most
potent inducer. Using the optimal concentration of uric acid as inducer, the conditions of uricase induction in the test organisms were optimized. In P. vulgaris strains (1753 and B-317-C), the
incubation temperature of 37 ºC, initial pH of culture media of 7 and agitation rate of 180 rpm, showed the highest level of uricase induction. In the two Streptomyces species, the uricase induction was optimized at 28 ºC incubation temperature and pH 7. The agitation rate of 200 and 220 rpm showed the highest induction activity in Streptomyces graminofaciens and S. albidoflavus, respectively. The highest levels of induced uricase were obtained at induction times of 140 min, 140 min, 42 h and 36 h in P. vulgaris 1753, B-317-C, Streptomyces graminofaciens and S. albidoflavus, respectively. The uricase was present as cell-bound enzyme in the producing organisms and no activity was recorded in the culture supernatants.