Production of Pigments and Photo-Protective Compounds by Cold-Adapted Yeasts

Abstract

The structure of microbial communities in cold environments is not only shaped by temperature; also other factors determine which species can survive. Ultraviolet radiation UVR) is one of these factors and only microorganisms bearing photoprotective defense mechanisms colonize environments exposed to high UVR levels. In yeasts collected from Patagonia, among other cold environments, secondary metabolites such as carotenoids and mycosporines appear to be produced as the most frequent photo-protective compounds. Production of carotenoids is quite common in cold-adapted yeasts, and some species produce unique carotenoids, like plectaniaxanthin and astaxanthin, which are not found in mesophilic species. On the other hand, production of mycosporines appears in several yeasts species, and has been intensively studied in yeasts isolated from high altitude Patagonian lakes, revealing that several cold-adapted yeasts, including Phaffia and Dioszegia, are mycosporine-producing species. Both compounds effectively protect yeast cells against UVR.