Cloning, Expression, and Characterization of a Novel Thermophilic Monofunctional Catalase fromGeobacillussp. CHB1

Abstract

Catalases are widely used in many scientific areas. A catalase gene (Kat) fromGeobacillussp. CHB1 encoding a monofunctional catalase was cloned and recombinant expressed inEscherichia coli(E. coli), which was the first time to clone and express this type of catalase ofgenus Geobacillusstrains as far as we know. ThisKatgene was 1,467 bp in length and encoded a catalase with 488 amino acid residuals, which is only 81% similar to the previously studiedBacillussp. catalase in terms of amino acid sequence. Recombinant catalase was highly soluble inE. coliand made up 30% of the totalE. coliprotein. Fermentation broth of the recombinantE. colishowed a high catalase activity level up to 35,831 U/mL which was only lower than recombinantBacillussp. WSHDZ-01 among the reported catalase production strains. The purified recombinant catalase had a specific activity of 40,526 U/mg andKmof 51.1 mM. The optimal reaction temperature of this recombinant enzyme was 60°C to 70°C, and it exhibited high activity over a wide range of reaction temperatures, ranging from 10°C to 90°C. The enzyme retained 94.7% of its residual activity after incubation at 60°C for 1 hour. High yield and excellent thermophilic properties are valuable features for this catalase in industrial applications.