Priestia megaterium

Priestia megaterium (Bacillus megaterium prior to 2020) is a rod-like, Gram-positive, mainly aerobic, spore forming bacterium found in widely diverse habitats. It has a cell length up to 100 μm and a diameter of 0.1 μm, which is quite large for bacteria. The cells often occur in pairs and chains, where the cells are joined by polysaccharides on the cell walls.

In the 1980s, prior to the use of Bacillus subtilis for this purpose, P. megaterium was the main model organism among Gram-positive bacteria for intensive studies on biochemistry, sporulation, and bacteriophages. Recently, its popularity has started increasing in the field of biotechnology for its recombinant protein-production capacity.