Bacteria are also beneficial to the human beings in many ways in spite of their many harmful effects. They have a great role in agriculture. Bacteria help in decaying of organic substances, increase the fertility of soil, help in ammonification, nitrification and fixation of nitrogen. Bacteria play very important role in various industries like medicine preparation of alcohols, preparation of vinegar, butter, cheese, tea, coffee, antibiotics, etc. They help in preparation of leather and tanning. These are the beneficial effects of bacteria.