Biosynthesis of selenium rich exopolysaccharide (Se-EPS) by Pseudomonas PT-8 and characterization of its antioxidant activities. (20th May 2016)

• Record Type: Journal Article
• Authors: Ye, Shuhong; Zhang, Jiajia; Liu, Zhaofang; Zhang, Yu; Li, Jiang; Li, Yao Olive
• Is Part Of: Carbohydrate polymers. Volume 142(2016)
• Page Start: 230
• Page End: 239
• Publication Date: 2016-05-20
• Subjects: Selenium rich exopolysaccharide -- Organo-selenium -- Biosynthesis -- Antioxidant activities -- Pseudomonas PT-8; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2016.01.058
• Languages: English
• ISSNs: 0144-8617

Abstract

Highlights: Biosynthesis of organo-selenium is achieved by fermentation of Pseudomonas PT-8. The Se-EPS has higher scavenging actions on DPPH, OH and O2 − than the EPS. Bioactivities of Se-EPS are related with many factors, such as molecular weight and monosaccharides. Abstract: Biosynthesis of organo-selenium is achieved by submerged fermentation of selenium-tolerant Pseudomonas PT-8. The end product of metabolic process is selenium-bearing exopolysaccharide (Se-EPS), which contains a higher content of uronic acid than the exopolysaccharide (EPS) by the strain without selenium in the culture medium. Selenium content in Se-EPS reached a maximum yield of 256.7 mg/kg when using an optimized culture condition. Crude Se-EPS was purified into two fractions—a pH neutral Se-EPS-1 and an acidic Se-EPS-2. Structure and chemical composition of Se-EPS-2 were investigated by chromatographic analyses. Results showed that Se-EPS-2 was a homogenous polysaccharide with molecular weight of 7.3 kDa, consisting of monosaccharides, rhamnose, arabinose, xylose, mannose, glucose and galactose with a molar ratio of 19.58:19.28:5.97:18.99:23.70:12.48, respectively. Compared to the EPS, the content of rhamnose in Se-EPS increased and molecular weight decreased. The Se-EPS had strong scavenging actions on DPPH, OH and O2 −, which is much higher than the EPS.