Ultraviolet-shielding bioplastic films from Antarctic <i>Klebsormidium</i> sp. ASYA19: A sustainable approach to plastic alternatives

This study presents an innovative UV-protective bioactive film derived from Antarctic Klebsormidium sp. ASYA19, cultivated under high light intensity and low temperature in an airlift photobioreactor. The microalgae exhibited peak UV-active biomolecule production during the late exponential growth phase, making this the optimal harvest point for bioplastic development. Bioplastics were successfully formulated using the crude microalgal biomass (CKB) alone and in various blends with polyvinyl alcohol (PVA) and glycerol as additives. Notably, a simple 5 % CKB suspension independently forms effective UV-shielding films demonstrating superior UVblocking capacity, particularly at 330 nm. PVA incorporation enhanced tensile strength (up to 12.10 MPa) but reduced UV-blocking efficacy through dilution effects. Glycerol increased flexibility while maintaining reasonable strength. FTIR spectroscopy and thermal analysis confirmed the effective integration of the additive through hydrogen bonding. These findings highlight the potential of Antarctic microalgae as a sustainable source for functional biomaterials with promising applications in UV-protective packaging and coatings.