- Levan is a naturally occurring polysaccharide composed mainly of fructose molecules linked together, typically through β-(2→6) glycosidic bonds, with some branching at β-(2→1) linkages.
- It belongs to the family of fructans, which are polymers of fructose. Unlike inulin, another fructan where the fructose units are linked mainly via β-(2→1) bonds, levan is distinguished by its β-(2→6) backbone. This structural difference gives levan unique physicochemical properties and biological functions. It is usually synthesized by bacteria, fungi, and some plants, often as an extracellular polysaccharide. In microbes, it is commonly produced through the action of the enzyme levansucrase, which catalyzes the transfer of fructosyl residues from sucrose to a growing levan chain.
- Levan has been widely studied for its biological activities and applications. It exhibits antioxidant, anticancer, anti-inflammatory, and immunomodulatory properties. Several studies suggest that levan can stimulate beneficial gut microbiota, acting as a prebiotic that supports intestinal health. In medicine, its biocompatibility and non-toxic nature have attracted attention for potential use in drug delivery, wound healing, and tissue engineering. For example, levan-based nanoparticles and hydrogels are being explored for targeted drug release and regenerative therapies. In food science, it is considered a functional ingredient because of its low caloric value, solubility, and ability to improve texture and stability of food products.
- Beyond health-related uses, levan has notable industrial applications. Its film-forming ability, adhesiveness, and biodegradability make it a candidate for eco-friendly coatings, packaging materials, and adhesives. It has also been tested as a stabilizer in cosmetics and as a component in bio-based plastics. Because it can be produced from inexpensive substrates like sucrose via microbial fermentation, levan offers a sustainable alternative to petroleum-based polymers in several industries.
