Bacterial Growth Requirements

Bacterial Growth Requirements
Evelyn Lyle
ITT Technical Institute
Angela Ask, MPS
January 15, 2012

Every organism must find in its environment all of the substances required for energy generation and cellular biosynthesis. The chemicals and elements of this environment that are utilized for bacterial growth are referred to as nutrients. Many bacteria can be identified in the environment by inspection or using genetic techniques. The nutritional requirements of a bacterium such as E Coli are revealed by the cell’s elemental composition. These elements are found in the form of water, inorganic ions, small molecules and macromolecules which serve either a structural or functional role in the cells. Bacteria thrive by four things oxygen, food (nutrients), warmth and time but two others can be moisture and acidity. Nutrients are needed for energy, nitrogen (for DNA and proteins), phosphorus (for energy), and others. Warmth is needed so the bacteria can stay warm. Oxygen is needed so the bacteria can make energy and time is needed for the bacteria to complete binary fission over and over again. Acidity is needed so the bacteria can survive in its environment. Highly base or acidic environments may harm the bacteria and hinder its lifespan. In order to survive and grow, microorganisms require a source of energy and nourishment. Bacteria are the most primitive forms of microorganisms but are composed of a great variety of simple and complex molecules and are able to carry out a wide range of chemical transformations. Depending on their requirements and the source of energy used they are classified into different nutritional groups. Most microorganisms grow well at the normal temperatures favored by man, higher plants and animals. Certain bacteria grow at temperatures (extreme heat or cold) at which few higher organisms can survive. Most bacteria grow best in an environment with a narrow pH range near neutrality between pH 6.5 and 7.5. Microbes contain approximately 80-90% water and I f placed in a solution with a higher solute concentration will lose water which causes shrinkage of the cell. Some bacteria have adapted so well to high salt concentrations that they actually require them for growth. Nitrogen and phosphorus are particularly critical because they often control the rates of photosynthesis. Carbon is significantly more abundant than either of them and oxygen and sulfur are more abundant that phosphorous. Nitrogen and phosphorous are less available to plants relative to their growth requirements than are other elements. Phosphorus is often in short supply and limits plant and algae growth. Nitrogen is a major constituent of all proteins and of all living organisms. A lack of nitrogen can limit growth of plants, since nearly three quarters of its atmosphere consists of natural gas, N2.

REFERENCES
A New Way to Look at Microorganisms. (n.d). American Scientist, 93(6), 514.

References: A New Way to Look at Microorganisms. (n.d). American Scientist, 93(6), 514.