Cold-adapted basidiomycetous yeasts as a source of biochemicals

Abstract

Yeasts play a relevant role as starter cultures in traditional foods and beverages, as well as in innumerable biotechnological applications for obtaining high-value bulk and fine biochemicals. Despite a considerable number of studies on yeasts have been performed by using almost exclusively the species Saccharomyces cerevisiae (otherwise labeled as baker's yeast), the number of yeast species described so far accounts for more than 1600, belonging to over 130 ascomycetous and basidiomycetous genera. This huge yeast diversity includes many non-Saccharomyces species possessing useful, and sometimes uncommon, metabolic features potentially interesting for both food and nonfood industries. Like other organisms, cold-adapted yeasts include species able to survive and grow in cold environments. They are usually labeled as psychrophiles or psychrotolerants on the basis of their cardinal growth temperatures. Among them, yeasts belonging to the phylum Basidiomycota apparently exhibit a superior adaptation to cold. This apparent superiority, which could be the result of some metabolic strategies implemented for adapting life to different thermal conditions in order to overcome the adverse effect of cold, can be considered worthwhile for implementing their biotechnological application at low temperatures. Accordingly, cold-adapted basid- iomycetous yeasts have attracted considerable attention for their biotechnological potential, because they have developed the ability to synthesize cold-active enzymes, as well as other important biochemicals, namely, cryoprotectant compounds, polymers, lipids, and other miscellaneous compounds.