Pullulan-Based Gels with Food-Related Orientation: From Microbial Production to Synergistic Assemblies

spp. It has attracted considerable attention due to its biodegradability, biocompatibility, and versatility in food-related applications. While its basic chemical structure has long been established, recent advances have significantly improved the understanding of the genetic, enzymatic, and regulatory mechanisms governing its biosynthesis. This review discusses current knowledge on pullulan production, focusing on biosynthetic pathways, regulatory networks, and the influence of fermentation conditions on polymer yield and quality. Particular emphasis is placed on the utilization of agro-industrial residues as renewable feedstocks within a circular bioeconomy framework, as well as on downstream recovery and purification strategies. Furthermore, the physicochemical properties of pullulan and its ability to form synergistic assemblies with other biopolymers are evaluated in relation to hydrogels, edible films, active packaging, and bioactive delivery systems. By integrating microbial biotechnology, bioprocess engineering, and material science, this review provides a comprehensive overview of pullulan-based systems for food-related applications.