Trehalose - Biological Properties

Biological Properties

In nature, trehalose can be found in animals, plants, and microorganisms. In animals, trehalose is prevalent in shrimp, and also in insects, including grasshoppers, locusts, butterflies, and bees, in which blood-sugar is trehalose. The trehalose is then broken down into glucose by the catabolic enzyme trehalase for use. Trehalose is also present in the nutrition exchange liquid of hornets and their larvae.

In plants, the presence of trehalose is seen in sunflower seeds, moonwort, Selaginella plants, and sea algae. Within the fungi, it is prevalent in some mushrooms, such as shiitake (Lentinula edodes), maitake (Grifola fondosa), nameko (Pholiota nameko), and Judas's ear (Auricularia auricula-judae), which can contain 1% to 17% percent of trehalose in dry weight form (thus it is also referred to as mushroom sugar). Trehalose can also be found in such microorganisms as baker's yeast and wine yeast, and it is metabolized by a number of bacteria, including Streptococcus mutans, the common oral bacterium responsible for dental plaque.

When tardigrades (water bears) dry out, the glucose in their bodies changes to trehalose when they enter a state called cryptobiosis — a state wherein they appear dead. However, when they receive water, they revive and return to their metabolic state. It is also thought that the reason the larvae of sleeping chironomid (Polypedilum vanderplanki) and artemia (sea monkeys, brine shrimp) are able to withstand dehydration is because they store trehalose within their cells.

Even within the plant kingdom, Selaginella (sometimes called the resurrection plant), which grows in desert and mountainous areas, may be cracked and dried out, but will turn green again and revive after a rain because of the function of trehalose. It is also said that the reason dried shiitake mushrooms spring back into shape so well in water is because they contain trehalose.

The two prevalent theories as to how trehalose works within the organism in the state of cryptobiosis are the vitrification theory, a state that prevents ice formation, or the water displacement theory, whereby water is replaced by trehalose, although it is possible that a combination of the two mechanisms is at work.

The enzyme trehalase, a glycoside hydrolase, present but not abundant in most people, breaks trehalose into two glucose molecules, which can then be readily absorbed in the gut.

Trehalose is the major carbohydrate energy storage molecule used by insects for flight. One possible reason for this is that the glycosidic linkage of trehalose, when acted upon by an insect trehalase, releases two molecules of glucose, which is required for the rapid energy requirements of flight. This is double the efficiency of glucose release from the storage polymer starch, for which cleavage of one glycosidic linkage releases only one glucose molecule.