High production, purification, biochemical characterization and gene analysis of a novel catalase from the thermophilic bacterium Ureibacillus thermosphaericus FZSF03

A catalase-producing thermophilic bacterium, Ureibacillus thermosphaericus FZSF03, was isolated from high-temperature compost. Catalase production in this strain increased 31 times and reached 57,630 U/mL after optimization in a shake flask, which might represent the highest catalase activity level among reported wild strains. This catalase was further purified and identified. The purified enzyme showed a specific activity of 219,360 U/mg, higher than many other catalases. The molecular weight of this enzyme is 52 kDa according to sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and the enzyme was identified as a monofunctional haeme catalase of Ureibacillus thermosphaericus by liquid chromatography-mass spectrometry (LC-MS)/MS. The optimal reaction temperature for this catalase was found to be 60 °C. Stability was observed at 60 °C and at a pH of 10.0, indicating the superiority of this enzyme at a high temperature and under alkaline conditions. Therefore, this catalase is a prospective candidate for industrial production and applications. The gene encoding this catalase is 1503 bp. As the amino acid sequence shows low similarity with other catalases, we suggest that this is a novel monofunctional haeme catalase.