RESUMO
Objective To screen a thermostable urate oxidase-producing strain, optimize the fermentation conditions and study the enzymatic properties.Methods A urate oxidase-producing strain was screened from high temperature starter based on transparent circle method.Its 16S rDNA sequence was then amplified and analyzed.Meanwhile, the phylogenetic trees were built.Optimization of the fermentation conditions from this strain was carried out.The enzymatic properties of urate oxidase were studied.Results A urate oxidase-producing strain, named Bacillus subtilis ZX-6 by molecular identification, was obtained.The production of urate oxidase under the optimized conditons (135.9 U/L) was 133.7%higher than before.The optimum reaction temperature and pH were 45℃ and 7.6 respectively.The residual activity of urate oxidase at 37℃ for 48 h was still 17.2%.Conclusion The successful screening of a thermostable urate oxidase-producing strain and optimization of the fermentation conditions will lay a foundation for the further research.