Perhaps the two best known functions of bacteria that are beneficial are their ability to break down waste, or dead materials to recycle nitrogen, and carbon, and their constant presence in the human gut of humans and animals where they help to protect against disease and aid in digestion. Some bacteria are helpful to humans as medicine, such as streptomycin, which is made from an organism found in the soil, Streptomyces griseus . It was the first antibiotic for tuberculosis.
Plants are helped by bacteria because they help with nutrient absorption; they help to turn the nitrogen from the atmosphere into protein. We use bacteria to make yogurt, Lactobacillus acidophillus. There are many less pathogen-type bacteria than friendly-type bacteria.