Purification and physicochemical characterization of exopolysaccharide produced by a novel brown-rot fungus Fomitopsis meliae AGDP-2

Abstract

The present study represents the purification and characterization of exopolysaccharide produced by Fomitopsis meliae AGDP-2. The water-soluble EPS obtained was purified using Sephadex G-75 column and characterized for its physical and biochemical properties. HPTLC and HPLC analysis indicated that EPS is composed of glucose and mannose residues. Many functional groups such as carboxyl, amide, hydroxyl, and glycosidic linkages were detected by FT-IR spectroscopy. Furthermore, glucose and mannose were detected from NMR spectra with α -(1→6) linkages, thereby signifying the heteropolymeric nature. Using GPC, molecular weight of EPS was estimated to be 2.48 × 10 6 Daltons. The SEM-EDX and AFM analysis revealed that EPS is compact and possesses cube-like structural units and nano-cracks with elemental composition of O, K, Na, Mg, S, Cl, and Ca. While studying its rheological behavior, EPS was found to be pseudoplastic in nature. As the physical properties and biochemical composition influence the bioactivities; the purified EPS from F. meliae AGDP-2 can be further evaluated for various bioactive properties such as antioxidant, anti-cancer, anti-inflammatory, antidiabetic, antibacterial, anti- biofilm, as well as antiviral properties. the present study was conducted to purify and characterize the EPS produced under submerged cultivation of Fomitopsis meliae AGDP-2. The characterization of EPS including monosaccharide composition (high-performance thin-layer chromatography [HPTLC] and HPLC), molecular weight (GPC), rheological behavior, surface morphology (SEM and AFM), as well as IR and nuclear magnetic resonance (NMR) spectra was thoroughly studied.