Direct Evidence of Microbial Sunscreen Production by Scum-Forming Cyanobacteria in the Baltic Sea.

Summary

Using HR-LC-MS and phylogenomics, the authors show that cyanobacterial surface scums in the Baltic Sea widely produce mycosporine-like amino acids (MAAs). Production of porphyra-334 and shinorine was confirmed, and 48% of species in the Anabaena/Dolichospermum/Aphanizomenon complex harbor MAA biosynthetic pathways, highlighting a scalable, bio-derived source for cosmetic UV filters.

Key Findings

• MAAs were detected in nearly all of 59 cyanobacterial surface scum samples (2021–2022) using high-resolution LC-MS.
• Phylogenomic mapping across 101 genomes showed 48% of species in the Anabaena/Dolichospermum/Aphanizomenon complex possess MAA biosynthetic pathways.
• Production of porphyra-334 and shinorine was confirmed; porphyra-334 content reached 7.4 mg/g dry weight in Dolichospermum sp. UHCC 0684.

Clinical Implications

While preclinical, findings inform cosmeceutical R&D pipelines for safer, bio-derived UV filters and may influence regulatory and sourcing strategies for sunscreens.

Limitations

• Environmental observational study; no assessment of industrial scalability, toxicity, or human efficacy.
• Temporal/seasonal and geographic constraints (Finland’s southern coast, two summers) may limit generalizability.

Future Directions

Evaluate sustainable cultivation/extraction, stability in formulations, safety profiles, and UV protection efficacy of MAAs in human-relevant models and clinical studies.