Use the drop-down menus to determine whether a bacterial example is beneficial or harmful to humans. Coriariaceae coriaria is a species of bacteria that helps convert nitrogen into a form usable by plants. Mycobacterium tuberculosis is a species of bacteria that causes the disease tuberculosis in people. Lactobacillus acidophilus is a species of bacteria that is found in yogurt and can help people improve their digestion. Lactobacillus sanfranciscensis is a species of bacteria that makes the sour flavor in sourdough bread. It gets its name from San Francisco, where a great deal of sourdough bread is made.