Halophiles and their features

Introduction:

• Halophiles are categorized under the domain Archaea.
• Archaebacteria are special bacteria that can survive in harsh environments
• Bacteria that can survive in salt-rich environments are known as halophiles.
• The cell membrane of archaebacteria consists of branched lipid molecules.
• The ability of archaebacteria to live in harsh habitats is attributed to its special cell membrane composition.

Definition:

• Halophiles are organisms that have the ability to survive salt-rich environments.

History:

• Halophiles were first discovered in 1980 by a group of authors. In the year 1982, in Zabuye Kaka, halophiles were found on a large scale in natural habitats.
  
  
  

Detailed explanation:

• Halo – Salt, phile – to love
  Hence, halophiles are organisms that are found in high salinity.
• They are unicellular mainly aerobic microorganisms.
• They can only grow in salt-rich habitats, hence, acquiring ecosystems such as the dead sea, great salt lake, salt pans, and salt marshes.
• A substrate having a 4 - 15% concentration of NaCl is a suitable environment for these microorganisms.
• Halophiles possess a purple pigmented membrane which helps them absorb light of high intensity.
• In the presence of oxygen, they use oxidative phosphorylation.
• However, the absence of oxygen results in photophosphorylation for ATP synthesis.
• Their colonies are red to orange due to carotenoids. Carotenoids help in the protection of cells against damaging sunlight.
• They reproduce by processes such as binary fission, multiple fission, fragmentation, budding.
• Halophiles are able to survive under high salt conditions due to the following reasons:
• - Presence of special lipids
  - Mucilage covering
  - Sap vacuoles are absent. Hence, plasmolysis does not occur.
  - High concentration of KCl that prevents desiccation
  - Enzymes have a higher tolerance to salinity.
• Example- Halobacterium salinarum, Salinibactor ruber

Frequently Asked Auestions (FAQs)

Q1. Can Halophiles grow without salt?
Ans. No, Halophiles require NaCl for their growth. They cannot survive in the absence of salt.

Q2. How does a Halophile maintain a positive water balance while growing in a solution high in NaCl?
Ans. Accumulation of potassium ions and different compatible organic solutes maintains osmotic balance in the cell body of a Halophile. Accumulation of compatible solutes in the cytoplasm helps microorganisms to maintain osmotic pressure under a high concentration of NaCl. Hence, affecting bodily function as little as possible.