Rapid production of extracellular thermostable alkaline halophilic protease originating from an extreme haloarchaeon, Halobacterium salinarum by recombinant Bacillus subtilis

Halophilic proteases are extremely useful in harsh environments during industrial manufacturing processes. Production of the enzymes by halophiles has been hampered with their slow growth and complicated purification processes. Here, we developed a rapid method for extremozyme production by recombinant Bacillus subtilis. HProPRW1, a halophilic protease from an extreme haloarchaeon Halobacterium salinarum PRW1, was expressed from a salt-inducible expression system in B. subtilis. Three different signal peptides were evaluated for HProPRW1 secretion, revealing an efficient function of the HProPRW1 native signal peptide in B. subtilis. At optimal conditions, HProPRW1 could be produced within 22 h by recombinant B. subtilis instead of 96 h by wild type. The recombinant enzyme functions most optimally at 60 °C, pH 9% and 12% NaCl. The crude enzyme was stable for at least 1 month at 4 °C. This new protocol can be applied for production of other high-value halophilic enzymes.