text: Bacteria plays a very important role in the nutrient cycle, such as the nitrogen cycle. They help decompose dead matter too, returning the nutrients in the dead matter back to the ecosystem.\n\nBesides that, there are lots of bacteria in the human gut, that plays an important role in aiding digestion. \n\nIn modern science, bacteria plays a big part in biotechnology, such as in the manufacture of cheese, yoghurt, production of wine etc. because bacteria is necessary in fermentation. It's also used as a vector, for splicing and inserting the insulin gene during the commercial production of certain drugs like insulin, for the diabetic patients.\n\nHope this helps =)