What Bacteria Eat

There are thousands of species of bacteria and it is possible to find a bacterium able to eat almost anything from sugar, to corn proteins, to soybean oil, to iron nails, to sulfur, to the compounds in wood. Yes, it is possible to find a bacterium able to feed on almost any of these materials. In fact, it has long been known that bacteria were involved in transforming soluble iron ions into the insoluble compounds of iron ores. Just as animals breathe oxygen to burn (oxidize) their food, Thiobacillus bacteria "breathe" (use) sulfur to oxidize their food. Each organism is using a specific element as an electron acceptor to complete its electron transport pathway that generates ATPs, the high-energy phosphate that most organisms use for energy. In human cells an atom of oxygen plus electrons; or in some bacteria a sulfur plus electrons (error: this is not eating, this is respiration), along with a food source such as sugars, proteins and vitamins are combined in order to live. The blue-green bacteria (some times called blue-green algae) have chlorophyll and can make their own food from light energy plus carbon dioxide. Some other bacteria have red chlorophylls and can use light and carbon dioxide to make the sugars they need.

Like all living things bacteria require mineral salts such as magnesium, calcium, iron, and others. Some bacteria are able to obtain the energy they need by oxidizing iron or sulfur. Some bacteria need sugars, vitamins, amino acids, and other growth factors already digested and ready to use. Other bacteria can digest proteins down to amino acids and digest complex carbohydrates such as starches and table sugar down to simple sugars. Some bacteria can make their own amino acids and vitamins from carbohydrates. The metabolic abilities of bacteria are among the traits we use to group them into genera, but the important fact is that bacteria consume the vast cross-section of natural, and most manmade, wastewater and solids.

As you can imagine from this discussion, there are numerous species of bacteria living in an astonishing variety of places and feed on every possible food you can imagine. Some can eat gasoline and other hydrocarbons, some on cellulose and wood pulp, and others still on various bio- wastes. While we often say some insects and animals like termites, beavers, and beetle larva can eat wood or sawdust. In fact, it is usually bacteria in their guts that eat the wood and the animal lives on the dead bacteria and substances they produce. The symbiosis between bacteria and the other planets and animals on the Blue Planet is fundamental to the cycle of life and natural process of organic conversion of inorganic elements.

If some new substance comes along, a bacterium may have an ability to eat it and that gives it a slight competitive edge because it can live when the others have run out of food. Over time minor changes in genetic material occur which are called mutations. If these minor changes help an organism to grow better than its competitors, that organism may outgrow his neighbors. That is one reason the balance between living things on earth slowly changes. Mutations are constantly occurring. Nearly all mutations are harmful, meaning the change is not quite as good as the original, but some mutations give an organism a slight advantage over its neighbors, and is past on to the next generation.

All life depends on the chemical cycling and decomposing preformed by bacteria, which can convert carbon and nitrogen from organic to inorganic forms. Prokaryotes (bacteria as defined by a cell without a DNA wall) made the atmosphere aerobic, and, most importantly, they gave rise to all Eukaryotes (defined as cells with nuclear DNA)

Habitats and Conditions

When most people think of bacteria, they think of disease- causing organisms, like the Streptococcus that cause strep throat. While pathogenic bacteria are notorious for such diseases as cholera, tuberculosis, and gonorrhea, such disease-causing species are a comparatively tiny fraction of the bacteria as a whole. Bacteria are so widespread that it is possible only to make the most general statements about their life history and ecology. They may be found on the tops of mountains, the bottom of the deepest oceans, in the guts of animals, and even in the frozen rocks and ice of Antarctica. One feature that has enabled them to spread so far, and last so long is their ability to go dormant for an extended period.