Wide pH range tolerance in extremophiles: towards understanding an important phenomenon for future biotechnology

Kusum Dhakar, Anita Pandey

Research output: Contribution to journalReview articlepeer-review

68 Scopus citations


Microorganisms that inhabit the extreme pH environments are classified as acidophiles and alkaliphiles. A number of studies emerged from extreme high (hot springs, hydrothermal vents) as well as low temperature (arctic and antarctic regions, sea water, ice shelf, marine sediments, cold deserts, glaciers, temperate forests, and plantations) environments have highlighted the occurrence of microorganisms (thermophiles/psychrophiles) with the ability to tolerate wide pH range, from acidic to alkaline (1.5–14.0 in some cases), under laboratory conditions. However, the sampling source (soil/sediment) of these microorganisms showed the pH to be neutral or slightly acidic/alkaline. The aim of the present review is to discuss the phenomenon of wide pH range tolerance possessed by these microorganisms as a hidden character in perspective of their habitats, possible mechanisms, phylogeny, ecological and biotechnological relevance, and future perspectives. It is believed that the genome is a probable reservoir of the hidden variations. The extremophiles have the ability to adapt against the environmental change that is probably through the expression/regulation of the specific genes that were already present in the genome. The phenomenon is likely to have broad implications in biotechnology, including both environmental (such as bioremediation, biodegradation, and biocontrol), and industrial applications (as a source of novel extremozymes and many other useful bioactive compounds with wide pH range tolerance).

Original languageEnglish
Pages (from-to)2499-2510
Number of pages12
JournalApplied Microbiology and Biotechnology
Issue number6
StatePublished - 1 Mar 2016
Externally publishedYes


  • Acidophiles
  • Adaptations
  • Alkaliphiles
  • Extremophiles
  • Indian Himalayan Region (IHR)
  • Wide pH tolerance

ASJC Scopus subject areas

  • Biotechnology
  • Applied Microbiology and Biotechnology


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