UV Radiation Triggers Mycosporine-Glutaminol-Glucoside Biosynthesis in Naganishia friedmannii FBU002, a non-pathogenic yeast.

Aims: Ultraviolet radiation (UVR) interferes with aspects of life on Earth. It is necessary for the synthesis of important molecules, as vitamin D, but it is harmful to organisms leading to photoaging and skin cancer. Artificial sunscreens prevent these harmful effects, but may be carcinogenic and neurotoxic; also they accumulate in the aquatic ecosystem, harming the environment and leading to coral bleaching. Most artificial sunscreens commercialized are fossil fuel derived and produced by the petrochemical industry. As society turns to bioeconomy, these artificial sunscreens may be substituted by sustainable ones. Algae, cyanobacteria and fungi produce mycosporines and mycosporine-like aminoacids, which absorb UV radiation and dissipate it as heat. They are a natural source of sunscreen with low or no toxicity and can be produced by biotechnological means; therefore, the aim of this study is to search for mycosporine biosynthesis in yeast from an extreme environment.

Methods And Results: chromatographic and spectroscopic data analyses demonstrated for the first time an isolate of Naganishia friedmannii, collected from a site with high UVR incidence, is able to produce mycosporine-glutaminol-glucoside (MGG) and its likely diastereoisomer, when exposed to PAR-UVR light. A biosynthetic gene cluster was identified in the N. friedmannii genome and shown to be induced in response to UVR by Real-Time PCR. Phenotypic characterization suggests N. friedmannii is non-pathogenic yeast that tolerates UVC radiation and other stresses.

Conclusions: these features make N. friedmannii suitable for biotechnological applications, adding value to yeast mycosporines as an additive for economically viable, sustainable and environmentally friendly sunscreens.