Types of Microorganisms & Optimum PH

••• SeventyFour/iStock/GettyImages

Different microorganisms often require distinct environments, with varied temperature, levels of oxygen, light and acidity or pH level. Some microbes grow faster in environments with extremely low pH values. These are called acidophiles, because of their preference for acidic environments. Although most microorganisms requires neutral pH values to have optimum growth, alkaliphilic microorganisms prefer low-acidity or high pH environment.

Acidophiles

Microorganisms which optimum growth at pH levels lower than 5 are called acidophiles. These microbes are found in a variety of environments, including geysers and sulfuric pools, as well as in the human stomach. Examples of acidophiles include the microscopic algae Cyanidium caldarium and Dunaliella acidophila. The microscopic fungi, Acontium cylatium, Cephalosporium and Trichosporon cerebriae can grow near pH 0. A primitive microorganism called Picrophilaceae have optimum pH values close to zero and can also grow at negative pH values.

Alkaliphilic

Alkaliphilic microorganisms have optimum growth at pH values between 9 and 12. These microorganisms thrive in alkaline lakes, soils and other high pH environments. In slag dumps of Lake Calumet, southeast Chicago, the water can reach a pH of 12.8, which is similar to caustic soda. Some bacteria related to the Clostridium and Bacillus live in that extremely alkaline environment. Mono Lake, in California, and Octopus Spring in Yellowstone Park are examples of environments were alkaliphilic microorganisms are found.

Neutrophiles

Neutral pH values, laying between 6 and 8, are more commonly found in nature. Along their evolution, most microorganisms have adapted to have optimum growths in acidity-neutral environments. These microorganisms are called neutrophiles, and include most species of microalgae and other organisms that form the phytoplankton, as well as some soil-dwelling bacteria and yeasts.

Pathogens and PH

Most microorganisms associated with human, animals and plant diseases are neutrophiles, such as Escherichia coli, which causes intestinal infections; Erwinia caratovora, a plant parasite; Pseudomonas aeruginosa, which causes a series of infection in humans and animals; and Streptococcus pneumoniae, which causes pneumonia. However, pathogens are also found among acidophiles and alkaliphilics. The bacterium Lactobacillus acidophilus have optimum growth in low pH levels, causing vaginal infections. The alkaliphilic bacterium Vibrio cholerae causes cholera in humans.

Related Articles

List of Neutrophilic & Acidophilic Heterotrophic Bacteria
Definition of Acidic Solution
What Types of Bacteria Produce Nitrate?
The Microorganisms Found in Sewage
Deep Ocean Plants
What Three Conditions Are Ideal for Bacteria to Grow?
What Is Bacteria Homeostasis?
Types of Bacteria Living in Acidic pH
Characteristics of Salmonella Bacteria
What Is the Optimum pH for Human Stomach Enzyme Activity?
Water pH & Pollution
What Plants Live in the Deep Ocean?
Characteristics of the Six Kingdoms of Organisms
Where Do Bacteria Live?
Science Projects That Are Already Done & Can Be Copied
The Chemical Composition of Nutrient Agar
Environmental Problems in the Lakes of the Adirondack...
How Does Eutrophication Affect pH?
Pathogenic Bacteria in Soil
Description of the Four Types of Aquatic Ecosystems

Dont Go!

We Have More Great Sciencing Articles!