title: Physicochemical Characterization of an Exopolysaccharide Produced by a Newly Isolated Weissella cibaria.
abstract: A high molecular weight (3037 kDa) dextran-like polysaccharide was purified from the culture broth of a probiotic Weissella cibaria. Dry weight of the exopolysaccharides (EPS) obtained after ethanol precipitation was 6.35 g/L by using sucrose as carbon source and was further purified by phenol:chloroform:isoamyl alcohol (25:24:1) extraction and acetone precipitation to white powder with 52% recovery. Rheological characterization revealed that it has a pseudoplastic behaviour and showed a temperature tolerance of up to 280 °C in thermogravimetric analysis. Fourier transform infrared (FTIR) spectra showed the characteristic peaks of polysaccharide such as hydroxyl group, α-pyranose, asymmetrical C-H stretching vibration of methyl group and carbonyl hydrogens of D-glucopyranose. The (1)H nuclear magnetic resonance (NMR) spectrum showed resonances of hydrogen corresponding to the glucosyl residue, a repeat unit of the biopolymer. The cell viability analysis of normal L6 cells treated with the Weissella EPS showed that it is noncytotoxic even up to the 500-μg/mL level. A 0.2% (w/v) supplementation of EPS in 2% (w/v) wheat starch preparation could reduce the degree of syneresis up to 45% and up to 75% with 1% EPS.
authors.affiliation: Biotechnology Division, National Institute for Interdisciplinary Science and Technology (NIIST), CSIR, Trivandrum, Thiruvananthapuram, 695 019, Kerala, India.
authors.forename: Dilna Sasidharan
authors.initials: DS
authors.lastname: Vasanthakumari
authors.forename: Surya
authors.initials: S
authors.lastname: Harikumar
authors.forename: Divya Jayakumar
authors.initials: DJ
authors.lastname: Beena
authors.forename: Ashok
authors.initials: A
authors.lastname: Pandey
authors.forename: Kesavan Madhavan
authors.initials: KM
authors.lastname: Nampoothiri
mesh_terms: D002236:Carbohydrate Conformation; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification*; D017550:Spectroscopy, Fourier Transform Infrared; D058836:Weissella / Q000737:chemistry* / Q000378:metabolism
chemical_list: D011135:Polysaccharides, Bacterial