Bacteria are microscopic life forms, typically with dimensions of a few microns and have several applications. Here is a small list of them:
- Wastewater treatment: Bacteria are capable of surviving on organic matter, in fact, it is their food. Bacteria are used in wastewater treatment plants for secondary treatment of sewage, in which organic matter is removed by bacteria, thus treating the wastewater.
- Bioremediation: Bacteria are also used for treatment of contaminants such as metals and chemicals (such as chlorinated solvents, etc.). This is especially useful for sites polluted with these contaminants.
- Pharmaceuticals: Bacteria are used in pharmaceutical industry for production of a number of chemicals of pharmaceutical value.
- Food industry: Bacteria are used in food industry for making a number of food items. One common example is yogurt (or curds) which is made by a bacterium of lactobacillus species.
Hope this helps.