Properties and current applications of bacterial cyclic β-glucans and their derivatives

Abstract

Cyclic β-glucans are unique constituents that are found in the periplasmic space and extracellular media of Agrobacterium, Rhizobium, Bradyrhizobium, Rhodobacter, Xanthomonas, and Ralstonia species. Based on their glycosidic linkages, they are classified into three groups composed of cyclic β-(1,2), β-(1,3)-β-(1,6), and β-(1,2)-α-(1,6) linked glucans. Their degrees of polymerization vary ranging from 10 to 40 glucose residues, and the backbone structure can be modified with non-sugar moieties. Since the macrocyclic oligosaccharides possess their own characteristics such as inherent three-dimensional structures, hydrogen bonding, and complex-forming abilities, various possible applications would be of interest in the field of green chemistry, separation science, pharmaceutical, and food industries. In this review, we have addressed the properties and current applications of bio-sourced cyclic β-glucans and their derivatives.