How Does Bacteria Feed?

A bacterium commonly feeds on organisms which are either living or dead. Quiet a few bacteria's produce their own food. They also use the process of Photosynthesis, converting food from carbon dioxide and water. Bacteria's are basically microscopic, unicellular organisms. Despite their range all the bacteria species have a tendency to exhibit attribute morphology.
Normally all bacteria's are spherical (known as coccus) or rod-shaped (known as bacillus). Bacteria's are generally harmful as well as useful to the atmosphere, humans and animals. Bacteria play a vital role in infections and diseases. Some operate as pathogens and cause tetanus, pneumonia, syphilis, cholera, food poisoning, tuberculosis etc.  

Bacteria's cause leaf spot, firelight and wilts in plants. They generally spread via air, water, contact and food. Their ability to degrade a large number of organic compounds is quiet amazing.

Many bacteria are parasites, which feed and get protection from a host organism, living or dead. Most disease-causing bacteria are parasites.

A few bacteria manufacture food directly. Some of these use photosynthesis, making food from carbon dioxide and water. Some of these (the cyanobacteria) use chlorophyll but most use other means. Others use chemosynthesis, making food from inorganic substances and water.

Bacteria are part of decomposers, which feed on dead and decaying organisms and their faeces. They secrete enzymes onto their food source such as a decaying leaf. These enzymes break down complex organic compounds (food), like carbohydrates and proteins into simple soluble or gaseous inorganic compounds. They absorb only a small amount of energy and nutrients for their own usage. Most of the energy is lost as heat and the remaining nutrients are released into the surrounding soil, air and water.