Gene Mining of Urease and Recombinant Expression in Bacillus subtilis

Abstract:

Ethyl carbamate (EC) is a potential carcinogenic chemical in yellow rice wine. Urease has attracted much attention because of its degradation of urea, the precursor of EC. To guarantee the food safety of rice wine, the gene encoding Bacillus amyloliquefaciens IT-45 urease (Ba-urease) was realized by gene mining and expressed in recombinant Bacillus subtilis. The enzyme activity of urease increased from 6.85 U/mL to 9.01 U/mL after the urease gene cluster reconstructed by the optimization of codon and ribosome binding site. The urease activity was further increased to 10.15 U/mL by adjusting the position of gene ureC. The optimal reaction condition of recombinant urease was 37 ℃ and pH 6.5~7.0. Under the optimal fermentation conditions, the enzyme activity reached 12.5 U/mL. The production of food-grade recombinant urease has potential application in traditional fermented food industry.