Dual-action antimicrobial and antioxidant kojic acid-grafted kefiran biopolymer via enhanced iron chelation

This study presents a cost-effective and straightforward synthesis for a functionalized polysaccharide, kefiran, by covalently grafting it with kojic acid to obtain KK. The new KK material demonstrated a significant morphological change, forming more compact aggregates than unmodified kefiran, as observed through scanning electron microscopy (SEM) and Dynamic Light Scattering (DLS). Thermogravimetric analysis (TGA) proved that the KK derivative has a greater ability to chelate iron, an essential element for bacterial growth. The most significant findings were the material’s enhanced biological properties. While unmodified kefiran had moderate antimicrobial activity against some Gram-positive bacteria, the functionalized KK material showed a dramatic improvement, especially against Gram-negative pathogens like E. coli and P. aeruginosa . This enhanced activity is attributed to a cooperative effect between the two components: kefiran’s disruption of cell membranes and kojic acid’s action in chelating iron. Furthermore, the KK derivative displayed a notable increase in its antioxidant activity and high cellular compatibility following 24 h of exposure. These results highlight a promising strategy for developing new, sustainable biopolymer-based materials with dual antimicrobial and antioxidant properties, suitable for a wide range of applications from food packaging to advanced biomedical devices.