Protease Deficient Bacillus anthracis with Improved Recombinant Protein Yield Capabilities

Species of Bacillus, such as Bacillus anthracis, Bacillus cereus, and Bacillus subtilis, are attractive microorganisms for recombinant protein production in view of their fast growth rate, high yield, and ability to secrete produced products directly into the medium. Bacillus anthracis is also attractive in view of its ability to produce anthrax toxin and ability to fold proteins correctly. This application claims a B. anthracis strain in which more than one secreted protease is inactivated by genetic modification. Such a protease-deficient B. anthracis has an improved ability to produce recombinant secreted proteins compared to other bacteria, particularly other Bacillus. Improvements include production of intact (i.e., mature full-length) proteins, often at high yield.