Agro-industrial waste: a potential feedstock for pullulan production

Abstract

Nowadays, the growing interest of using of biopolymer to replace petroleum based material asare increasing tremendously. Microbial biopolymers are usually water-soluble gum which have innovative and unique physical characteristics.Pullulan is a biodegradable and water soluble exopolysaccharide synthesized by the yeast-like fungus Aureobasidium pullulans. This polymorphic fungus is well known as producer of the polysaccharide, pullulan and other by-products such as oil, organic acids, pigment, and others. Pullulan has extensive applications in pharmaceutical, cosmetic, biomedical, and food industries because of its advantageous chemical and physical properties. Pullulan’s structure is co-existence of á-(1, 4) and á-(1, 6) linkages which is nontoxic, tasteless and non-mutagenic. Some of its excellent properties are low viscosity, non-toxicity, slow digestibility, high plasticity, and excellent film-forming capabilities. Although pullulan shows great potential in several industries, its high production cost is a major drawback. Therefore, cheaper and accessible substrate which can minimize the production cost is needed. This review highlights the potential use of agro-industrial waste as an alternative source feedstock for pullulan production and its biosynthesis, chemical structure, production process and applications.