Microbes include bacteria, fungi, algae and protozoa. Bacteria is used in making curd, cheese, vinegar, antibiotics, vaccines, biogas. They also fix atmospheric nitrogen and help in recycling of nutrients in nature. Fungi is used as food (mushroom), in making alcohol, wine, beer, antibiotics, bread and recycling of nutrients. Algae is a source of iodine, food, fertili crs, agar and constitutes the first link in the food chain. Protozoa form a link in the food chain and help in adding nutrients to the soil.