Organisms ranging from bacteria, yeast, fungi, insects, invertebrates, and lower and higher plants have enzymes that can make trehalose.
In nature, trehalose can be found in plants, and microorganisms.  In animals, trehalose is prevalent in shrimp, and also in insects, including grasshoppers, locusts, butterflies, and bees, in which trehalose serves as blood-sugar. Trehalase genes are found in tardigrades, the microscopic ecdysozoans found worldwide in diverse extreme environments.
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.
In plants, 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), oyster, king oyster, and golden needle.
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 rain because of the function of 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.
In bacterial cell wall, trehalose has a structural role in adaptive responses to stress such as osmotic differences and extreme temperature. Yeast uses trehalose as a carbon source in response to abiotic stresses. In humans, the only known function of trehalose is its ability to activate autophagy inducer.
Trehalose has also been reported for anti-bacterial, anti-biofilm, and anti-inflammatory (in vitro and in vivo) activities, upon its esterification with fatty acids of varying chain lengths.