An osmophile is a microorganism adapted to environments with high
osmotic pressures, such as high sugar concentrations. Osmophiles are similar to
halophile
The halophiles, named after the Greek word for "salt-loving", are extremophiles that thrive in high salt concentrations. While most halophiles are classified into the domain Archaea, there are also bacterial halophiles and some eukaryotic species, ...
s (salt-loving organisms) in that a critical aspect of both types of environment is their low
water activity
Water activity (''aw'') is the partial vapor pressure of water in a solution divided by the standard state partial vapor pressure of water. In the field of food science, the standard state is most often defined as pure water at the same tempe ...
, a
W. High sugar concentrations represent a
growth-limiting factor
A limiting factor is a variable of a system that causes a noticeable change in output or another measure of a type of system. The limiting factor is in a pyramid shape of organisms going up from the producers to consumers and so on. A factor not l ...
for many microorganisms, yet osmophiles protect themselves against this high osmotic pressure by the synthesis of
osmoprotectant
Osmoprotectants or compatible solutes are small organic molecules with neutral charge and low toxicity at high concentrations that act as osmolytes and help organisms survive extreme osmotic stress. Osmoprotectants can be placed in three chemical c ...
s such as
alcohols and
amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...
s. Many osmophilic microorganisms are
yeast
Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constit ...
s; some bacteria are also osmophilic.
Osmophilic yeasts are important because they cause spoilage in the sugar and sweet goods industry, with products such as fruit juices, fruit juice concentrates, liquid sugars (such as golden syrup), honey and in some cases marzipan. Among the most osmophilic are:
References
*
*
{{Extremophile
*