Biosynthesis and Applications of Pullulan Polymers

Pullulan is a linear extracellular polysaccharide secreted predominantly by the yeast-like fungus Aureobasidium pullulans. Its unique structure, comprising maltotriose units linked by α-1,6 glycosidic bonds, confers water solubility, film-forming capability, and biodegradability. Biosynthesis begins with intracellular UDP-glucose assembly, followed by polymerisation and controlled secretion through dedicated transporters. Regulation of pullulan synthesis involves multiple genes encoding glycosyltransferases, transport proteins and pathway modulators, which can be engineered to tune molecular weight and yield. Fermentation parameters—carbon and nitrogen source, pH, temperature and aeration—are also critical determinants of productivity and polymer characteristics. These combined genetic and process interventions have driven improvements in cost-efficiency and scalability.

Owing to its biocompatibility, non-toxicity and mechanical versatility, pullulan has found diverse applications. In the biomedical realm it serves as a matrix for drug delivery, wound dressing and tissue-engineering scaffolds. In food science it forms edible films and coatings that extend shelf life and preserve freshness. In personal care and cosmetics, pullulan is employed for its moisture-retention and sensory properties. Emerging uses include antimicrobial packaging, green electronics and environmental remediation, where pullulan’s ability to stabilise nanoparticles and bind pollutants is exploited. Collectively, these applications underscore the polymer’s global significance as a sustainable alternative to petrochemical plastics.

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Biosynthesis and Applications of Pullulan Polymers publication trend

The graph below shows the total number of articles in biosynthesis and applications of pullulan polymers across all publications each year (not limited to Nature Index journals).

Technical terms

Exopolysaccharide: A high-molecular-weight polymer secreted by microorganisms into the extracellular environment.

Glycosidic bond: A covalent linkage between sugar monomers; pullulan contains α-1,4 and α-1,6 bonds connecting maltotriose units.

Molecular weight (Mw): The average mass of polymer molecules, influencing viscosity, mechanical strength and solubility.

Film-forming capability: The ability of a polymer solution to dry into a coherent, flexible film without additives.

Biocompatibility: The property of a material to interact with biological systems without eliciting adverse effects.

References

1. Pullulan for Advanced Sustainable Body- and Skin-Contact Applications. Journal of Functional Biomaterials (2020).
2. Emerging Trends in Pullulan-Based Antimicrobial Systems for Various Applications. International Journal of Molecular Sciences (2021).
3. High-level production of pullulan and its biosynthesis regulation in Aureobasidium pullulans BL06. Frontiers in Bioengineering and Biotechnology (2023).