Production, structure and morphology of exopolysaccharides yielded by submerged fermentation of Antrodia cinnamomea

Abstract

Carbon and nitrogen sources in culture medium of Antrodia cinnamomea were optimized to eliminate the interference of exterior macromolecules on exopolysaccharide (EPS) yield by submerged fermentation. The results suggested that culture medium containing 50 g/L of glucose and 20 g/L of yeast extract as the optimal carbon and nitrogen sources could produce 1.03 g/L of exopolysaccharides. After purification, two heteropolysaccharides (AC-EPS1 and AC-EPS2) were obtained and characterized to provide the basic structure information. As the main component of the produced EPS, AC-EPS2 (accounting for 89.63%) was mainly composed of galactose (87.42%) with M_w (molecular weight) and R.M.S. (root-mean-square) radius of 1.18 × 10⁵ g/mol and 25.3 nm, respectively. Furthermore, the spherical and flexible chain morphologies of EPS were observed in different solvents by TEM. The structural and morphological information of purified EPS were significant for further study on their structure-activity relationship and related applications.

Keywords: Antrodia cinnamomea; Exopolysaccharide; Morphology; Structural characterization; Submerged fermentation.