Abstract

Ultraviolet radiation (UV-R) exerts multiple harmful effects on human skin, primarily through the formation of DNA photoproducts such as cyclobutane pyrimidine dimers (CPDs) and 6-4 pyrimidine-pyrimidone dimers. These lesions can trigger cell death or mutations, contributing to non-melanoma skin cancer and photoaging. Photolyase is a light-dependent DNA repair enzyme that specifically reverses these photoproducts through photoreactivation. Although absent in humans, photolyase is naturally expressed in algae (micro-and macro-algae) and cyanobacteria. Due to its proven DNA repair activity, photolyase is encapsulated in liposomes and incorporated into dermatological and cosmetic formulations. Currently, Synechococcus spp. represents the primary natural source for commercial applications; however, increasing interest has emerged in exploring alternative microalgae species as potential photolyase producers. This review examines photolyase expression and activity across algal and cyanobacterial species, with emphasis on stress-induced regulatory mechanisms such as UV and light intensity that may enhance enzyme productivity. Strategies for optimizing bioprocess development, including upstream induction and downstream formulation, are also discussed. Additionally, the growing market demand for naturally sourced bioactives is addressed through an overview of recent trends in photolyase-based skin care products and patents. By highlighting the potential of underexplored microalgae and cultivation strategies, this review supports the development of novel, and sustainable platforms for photolyase production.