Microorganisms in extreme sugar concentrations (Osmophiles)


Osmophile Definition and Characteristics

  • Osmophiles are a group of organisms that are adapted to survive in environments with high osmotic pressures like high sugar concentration.
  • Osmophilic organisms are similar to halophiles, and xerophiles as all of them have the capacity to survive in environments with low water activity.
  • Osmophiles are mostly found in food with high sucrose content and environments with high osmolarity.
  • Fungi are the most common group of organisms that survive as osmophiles. However, organisms of the group Archea and Bacteria are also important osmophiles.
  • Osmophilic organisms are found in different parts of the world, especially in areas with high sugar content like food sources.
  • The ability to adapt to fluctuations in external osmotic pressure and the development of specific mechanisms to achieve the adaption is fundamental to the survival of cells.
  • Most cells maintain an osmotic pressure in the cytoplasm that is higher than that of the surrounding environment, resulting in an outward-directed pressure, turgor, whose maintenance is essential for cell division and growth.
  • Any changes in environmental osmolarity can trigger the flux of water across the cytoplasmic membrane.  Thus, osmophilic organisms develop different mechanisms to overcome the osmotic imbalance.

Osmophile Mode of adaptation


  • Osmophiles produce different osmoprotectants like alcohols and amino acids that prevent the change in osmotic pressure inside the cell.
  • These solutes increase the osmotic pressure inside the cell so as to balance the turgor pressure on the cell from the outside environments.

  • Proteins and enzymes in osmophiles have more protein charges and hydrophobicity that protects them against the change in the solute composition in the cytoplasm.
  • The unfavorable interactions that disrupt internal microbial proteins caused by dehydration may be averted by modulating their net charge.

Osmophile Examples

  • Some common examples of osmophiles include Zygosaccharomyces, Torula, Schizosaccharomyces octosprus, etc.

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