Microbial exopolysaccharides: Synthesis pathways, types and their commercial applications

Polysaccharides are essential natural metabolites found in all life forms such as microorganisms, animals and plants with various biochemical structures and biological functions. Among all the life forms microbial exopolysaccharides are produced in shorter time duration as they responsible for the microbial cell adhesion and protection during unfavorable growth conditions. Microbial exopolysaccharides are composed of repeated sugar units of same or different types and form a complex by associating with proteins, lipids, metal ions, extracellular DNA (eDNA), organic and inorganic compounds to form a protective layer around the microbial colonies collectively known as biofilm. Specific functions of exopolysaccharides depend on structural composition and habitat of a host microorganism. There are various techniques to study the composition and structure of exopolysaccharides such as High Performance Anion Exchange Chromatography with Pulsed Amperometric Detection, Size Exclusion Chromatography coupled with multi-laser light scattering (SEC-MALLS),X-Ray diffraction (XRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared (FTIR) and Thermal Gravimetric Analysis (TGA), etc. In the current article, we reviewed microbial exopolysaccharides physiochemical properties, composition, analyzing techniques through which possible commercial applications in dairy products, cosmetics, research, agriculture and petroleum industry can be performed. (C) 2020 Elsevier B.V. All rights reserved.