Bacillus subtilis bacteria use their flagella for a swarming motility. This motility occurs on surfaces, for example on agar plates, rather than in liquids. Bacillus subtilis are arranged in singles or chains. Cells arranged next to each other can only swarm together, not individually. These arrangements of cells are called 'rafts'. In order for Bacillus subtilis bacteria to swarm, they need to secrete a slime layer which includes surfactin, a surface tension-reducing lipopeptide, as one of its components (Schaechter 2006).
Bacillus subtilis bacteria have been considered strictly aerobic, meaning that they require oxygen to grow and they cannot undergo fermentation. However, recent studies show that they can indeed grow in anaerobic conditions making them facultative aerobes. The bacteria can make ATP in anaerobic conditions via butanediol fermentation as well as nitrate ammonification. Bacillus subtilis can use nitrite or nitrate as a terminal acceptor of electrons. Bacillus subtilis contains two unique nitrate reductases. One is used for nitrate nitrogen assimilation and the other is used for nitrate respiration. However, there is only one nitrite reductase that serves both purposes. Nitrate reductase reduces nitrate to nitrite in nitrate respiration, which is then reduced to ammonia by nitrite reductase. Bacillus subtilis is different from other facultative aerobes in that it undergoes fermentation without external acceptors of electrons (Nakano 1998). During fermentation, the regeneration of NAD+ is chiefly mediated by lactate dehydrogenase, which is found in the cytoplasm. Lactate dehydrogenase converts pyruvate to lactate (Marino 2001).
Bacillus subtilis contains catalase KatA and MrgA, an enzyme that is responsible in the catalysis of the decomposition of hydrogen peroxide to water and oxygen, and superoxide dismutase, an enzyme that catalyzes the breakdown of superoxide into oxygen and hydrogen peroxide (Bandow 2002).