The key difference between acidophiles neutrophiles and alkaliphiles is that acidophiles are microorganisms that grow at a pH near to 3 while neutrophiles are microorganisms that grow at a pH near to neutral or 7 and alkaliphiles are microorganisms that grow well between the pH of 8 to 10.5.
Microbes need certain conditions for their growth. pH is one such requirement. Based on the optimum growth pH, we can categorize microorganisms into three major groups as acidophiles neutrophiles and alkaliphiles. Acidophiles prefer pH near 3; neutrophiles prefer pH near 7; alkaliphiles grow well between pH 8 and 10.5. When the pH is not in the required growth pH range, they show a slow growth or they don’t grow. Most bacteria are neutrophiles.
CONTENTS
1. Overview and Key Difference
2. What are Acidophiles
3. What are Neutrophiles
4. What are Alkaliphiles
5. Similarities Between Acidophiles Neutrophiles and Alkaliphiles
6. Side by Side Comparison – Acidophiles vs Neutrophiles vs Alkaliphiles in Tabular Form
7. Summary
What are Acidophiles?
Acidophiles are the microorganisms that grow best at a pH near 3. Generally, they grow in acidic pH conditions, especially below pH 5. Archaea bacteria can survive at pH 2.5 to 3.5. Some species of Archaea can live pH between 0 to 2.9. Several bacteria, including several Thiobacillus species, are acidophiles. In addition to archaea and bacteria, there are acidophilic fungi and algae as well. Microscopic algae, Cyanidium caldarium and Dunaliella acidophila, and microscopic fungi, Acontium cylatium, Cephalosporium and Trichosporon cerebriae, are acidophiles. Acidophiles are found in volcanic areas, hydrothermal sources, deep-sea vents, geysers and sulfuric pools or in the stomachs of animals. These microorganisms are generally used in food preservation such as pickling.
What are Neutrophiles?
Neutrophiles are microorganisms that prefer a pH around 6.5 to 7.5 in order to grow optimally. Most bacteria, including human pathogenic bacteria, are neutrophiles. In addition to bacteria, there are neutrophilic microalgae, phytoplankton, and yeasts. These microbes prefer neutral environments. Therefore, they are commonly found in nature.
Figure 01: Neutrophiles
Most microorganisms that are associated with human, animal and plant diseases are neutrophiles. Escherichia coli, Pseudomonas aeruginosa, Streptococcus pneumonia and Erwinia caratovora are neutrophiles.
What are Alkaliphiles?
Alkaliphiles are microbes that grow well between pH 8 and 10.5. Extreme alkaliphiles show optimum growth pH 10 or higher. Alkaliphiles are usually found in soda lakes and high carbonate soils and sometimes even in garden soils. Agrobacterium is an extreme alkaliphile that grows optimally at pH 12.
Figure 02: Alkaliphiles
Alkaliphiles are industrially important in producing biological detergents. These detergents contain alkaline enzymes, such as alkaline cellulases and/or alkaline proteases produced from alkaliphiles.
What are the Similarities Between Acidophiles Neutrophiles and Alkaliphiles?
- Acidophiles, neutrophiles and alkaliphiles are three groups of microorganisms categorized based on the basis of pH requirement.
- All acidophiles, neutrophiles and alkaliphiles are commercially important.
What is the Difference Between Acidophiles Neutrophiles and Alkaliphiles?
The key difference between acidophiles neutrophiles and alkaliphiles depends on the optimal growth pH of each type of microbes. Acidophiles grow optimally at pH near 3 while neutrophiles grow optimally at pH 7 and alkaliphiles grow optimally between ph 8 and 10.5. Moreover, acidophiles are found in volcanic areas, hydrothermal sources, deep-sea vents, or in the stomachs of animals, while neutrophiles are found in nature and alkaliphiles are found in soda lakes and high carbonate soils and sometimes even in garden soils
The below infographic summarizes the differences between acidophiles neutrophiles and alkaliphiles.
Summary – Acidophiles Neutrophiles vs Alkaliphiles
Microorganisms live and thrive within specific pH levels. Based on the optimum growth pH, there are three groups of microorganisms. Acidophiles thrive in acidic environments while neutrophiles thrive in neutral environments and alkaliphiles thrive in alkaline environments. Thus, this is the key difference between acidophiles neutrophiles and alkaliphiles.
Reference:
1. Keenleyside, Wendy. “9.5 The Effects of PH on Microbial Growth.” Microbiology Canadian Edition, Pressbooks, 23 July 2019, Available here.
2. Jin, Qusheng, and Matthew F. Kirk. “PH as a Primary Control in Environmental Microbiology: 1. Thermodynamic Perspective.” Frontiers, Frontiers, 9 Apr. 2018, Available here.
Image Courtesy:
1. “E. coli Bacteria (16578744517)” By NIAID – E. coli Bacteria (CC BY 2.0) via Commons Wikimedia
2. “20101017 175758 Bacilli” By Bob Blaylock – Own work (CC BY-SA 3.0) via Commons Wikimedia