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Aerobic Bacteria

Aerobic Bacteria

Aerobic bacteria require oxygen to perform cellular respiration and derive energy to survive. In short, aerobic bacteria grows and multiplies only in the presence of oxygen. To know more about aerobic bacteria, read on.
Ningthoujam Sandhyarani
Last Updated: Apr 6, 2018
Mention bacteria and nearly all of us assume them to be disease-causing microbes. However, not many of us know that bacteria play a major role in the overall functioning of our ecosystem. Believe it or not, a major biomass of the earth is contributed by minute bacterial cells. Consequently, the variability of bacteria in terms of shape, size, dwelling place, feeding habit, and surviving requirements is extremely vast.

Bacteria are omnipresent, meaning that they are found in any type of environmental conditions. Some of the species are isolated from the least hospitable areas like hot springs, below the earth's crust, and in radioactive wastes. So, you can imagine the adaptability of bacteria in comparison to other living beings. Based on whether oxygen is required for survival or not, bacteria are classified as aerobic and anaerobic. This article introduces you to aerobic bacteria with examples and tells you how they differ from the anaerobic ones.
Types of Aerobic Bacteria Aerobic bacteria require oxygen for survival. Various types of aerobic bacteria are enlisted here.

Obligate Aerobes: These bacterial strains compulsorily require oxygen for deriving energy, growth, reproduction, and cellular respiration.

Facultative and Microaerophiles: Contrary to obligate aerobes, there are anaerobic bacteria, which live in a non-oxygenated environment throughout their life. Intermediary to these two groups are facultative bacteria (e.g., E. coli, Staphylococcus) and microaerophilic bacteria (e.g., Campylobacter, Helicobacter pylori). Facultative bacteria behave both aerobically and anaerobically, according to the prevailing conditions. Those of the microaerophilic type require oxygen, but in very low concentrations.

How to distinguish between Aerobic and Anaerobic Bacteria In microbiology and biology experiments, obligate aerobic bacteria can be isolated easily by culturing a mass of bacterial strains in a liquid medium. Since they are oxygen-needing organisms, they tend to collect in the top surface of the liquid medium, so as to absorb the maximum oxygen available to them.

Examples of Aerobic Bacteria
Studying the characteristic features and importance of bacteria is a major part of bacteriology. Mentioned below are some examples of aerobic bacteria and their characteristic features:

The genus Bacillus encompasses both obligate and facultative types of bacterial species. They include free living or pathogenic strains. For example, B. subtilis is a free-living soil bacterium, while B. anthrax infection causes anthrax disease. Ubiquitous in habit and having a large-sized genome, various species of Bacillus are commercially used for enzyme production and genetic researches.

Mycobacterium tuberculosis
As the name suggests, it is a species of pathogenic bacteria that cause tuberculosis. It is a rod shaped, obligate aerobic bacteria, characterized by the presence of a waxy layer on the wall. Being an oxygen-needing species, M. tuberculosis infects the lungs of mammalians, where oxygen is present in very high amounts. It divides at a very slow rate, after about 15 hours of infection.

Rod-shaped and gram positive type, the genus nocardia comprises more than 80 species. Out of these, some are capable of causing health conditions, while others are non-pathogenic. The disease caused by infection of nocardia is called nocardiosis, affecting only the lungs or the whole body. Usually, nocardia thrives in the oral cavity, mostly in the gums and periodontal pockets.

Lactobacillus is not a true aerobic bacteria, but it is included in the facultative type. You might have already heard about the application of this bacterium in curdling and fermentation of food items. It is normally found in the oral cavity and intestines without causing any symptoms. Rather, some Lactobacillus species are beneficial for health and classified as probiotic flora.

Pseudomonas Aeruginosa
Pseudomonas Aeruginosa is an gram-negative, rod shaped, obligate bacterium that causes diseases in humans and animals. It attacks people with a weak immune system. It is found everywhere in the environment. Infections caused by this bacterium are characterized by inflammations. If this infection occurs in the lungs or other vital organs, it can prove to be fatal. Diseases caused by it are pneumonia, urinary tract infections, and gastrointestinal infections. In addition to the above-mentioned strains, the list of aerobic bacteria includes Staphylococcus (facultative) and Enterobacteriacae species (facultative) among others. The major roles of aerobic bacteria include recycling of nutrients, decomposing waste products, and assisting in plant nutrient absorption. As they play a crucial role in the efficient working of septic systems, aerobic bacteria generators used in tanks. Bacteria from the generator aid in digesting harmful gases, foul odor, and help with other waste digesting problems.