Abstract

A novel microbial exopolysaccharide (EPS) was isolated from Enterobacter cloacaeZ0206. The pyruvyl groups of the polysaccharide were identified by ultraviolet (UV) spectra, nuclear magnetic resonance (¹H NMR, ¹³C NMR) spectra, quadruple time-of-flight electrospray ionization mass spectrometry (Q-TOF-ESI-MS) and reversed phase-high performance liquid chromatography (RP-HPLC). To measure the pyruvyl groups, a microbial polysaccharide was hydrolyzed using 3M trifluoroaceticacid (TFA) at 120°C and subsequently analyzed by isocratic RP-HPLC and UV detection at 215 nm. Results showed that the linear range for the pyruvate was from 0.0025 to 0.5 g/L with a detection limit (signal-to-noise ratio of 3) of 0.05 mg/L, and the recovery rate ranged from 100.2 to 101.6%. This method can be used to determine the pyruvate content in acid hydrolysates of crude polysaccharides without the need for complex pre-treatment.

Key words: Microbial polysaccharide, pyruvate, identification.