Characterization of Exopolysaccharide Produced by Streptococcus thermophilus CC30

• Published in: BioMed research international 2017-01, Vol.2017 (2017), p.1-11
• Main Authors: Kanamarlapudi, Sri Lakshmi Ramya Krishna, Muddada, Sudhamani
• Format: Article
• Language: English
• Subjects: Animals; Atomic force microscopy; Bacteria; Biomedical research; Biopolymers; Carbohydrates; Chromatography; Degradation; Electron microscopy; Emulsification; Exploitation; Fermentation; Food; Food industry; Food processing industry; Fourier transform infrared spectroscopy; Fourier transforms; Free Radical Scavengers - chemistry; Galactose; Galactose - chemistry; Hydrogen peroxide; Hydrogen Peroxide - chemistry; Infrared spectroscopy; Lactose; Lactose - chemistry; Microorganisms; Milk; Milk - chemistry; Milk - microbiology; Molecular Weight; Physiological aspects; Polysaccharides, Bacterial - biosynthesis; Polysaccharides, Bacterial - chemistry; Polysaccharides, Bacterial - isolation & purification; Pseudoplasticity; Rheology; Scanning electron microscopy; Scavenging; Skim milk; Spectroscopy, Fourier Transform Infrared; Streptococcus; Streptococcus thermophilus - chemistry; Temperature effects; Thermogravimetric analysis; Viscosity; Yogurt
• ISSN: 2314-6133; 2314-6141
• DOI: 10.1155/2017/4201809

An exopolysaccharide (EPS) producing strain CC30 was isolated from raw milk and identified as Streptococcus thermophilus with morphological and 16S sequencing analysis. The strain was shown to produce 1.95 g/L of EPS when grown in skim milk lactose medium at 30°C by increasing the viscosity of the medium. The EPS was isolated and purified, and it was shown to consist of glucose and galactose in 1 : 1 ratio, with molecular weights ranging from 58 to 180 kDa. FTIR spectroscopy indicated the EPS to have amide, hydroxyl, and carboxyl groups. Under Atomic Force Microscopy, EPS showed spike-like lumps of EPS. Scanning Electron Microscopy (SEM) studies showed that it had irregular lumps with a coarse surface. The EPS displayed pseudoplastic nature. Thermogravimetric analysis (TGA) reported a degradation temperature of 110.84°C. The purified EPS exhibited reducing activity, hydrogen peroxide radical scavenging activity, and emulsification activity. The results of the present study indicated that EPS producing Streptococcus thermophilus could serve as a promising candidate for further exploitation in food industry.