The invention relates to a Bacillus anthracis (B. anthracis) 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. The disclosure provides a B. anthracis that comprises a genetic modification that inactivates a protease of the M4 family of metallopro teases and a genetic modification that inactivates a protease of the M6 family of metalloproteases. Also provided is a modified B. anthracis comprising such genetic modification transformed with a recombinant molecule encoding a product, as well as methods to prepare and use such B. anthracis.
