title: Biosynthesis of selenium rich exopolysaccharide (Se-EPS) by Pseudomonas PT-8 and characterization of its antioxidant activities.
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.
authors.affiliation: School of Food Science, Dalian Polytechnic University, Dalian 116034, China. Electronic address: hlcyeshuhong@hotmail.com.
authors.forename: Shuhong
authors.initials: S
authors.lastname: Ye
authors.affiliation: Zhongpin Corporation, Zhengzhou 622776, China.
authors.forename: Jiajia
authors.initials: J
authors.lastname: Zhang
authors.affiliation: School of Food Science, Dalian Polytechnic University, Dalian 116034, China.
authors.forename: Zhaofang
authors.initials: Z
authors.lastname: Liu
authors.affiliation: School of Food Science, Dalian Polytechnic University, Dalian 116034, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Food Science, Dalian Polytechnic University, Dalian 116034, China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Li
authors.affiliation: Human Nutrition and Food Science, California State Polytechnic University, Pomona, CA 91768, USA.
authors.forename: Yao Olive
authors.initials: YO
authors.lastname: Li
mesh_terms: D053898:Biosynthetic Pathways; D001713:Biphenyl Compounds / Q000737:chemistry; D005285:Fermentation; D016166:Free Radical Scavengers / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D017665:Hydroxyl Radical / Q000737:chemistry; D016566:Organoselenium Compounds / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D010851:Picrates / Q000737:chemistry; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D011549:Pseudomonas / Q000737:chemistry / Q000378:metabolism*; D026082:Singlet Oxygen / Q000737:chemistry
chemical_list: D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D016566:Organoselenium Compounds; D010851:Picrates; D011135:Polysaccharides, Bacterial; D026082:Singlet Oxygen; D017665:Hydroxyl Radical; C004931:1,1-diphenyl-2-picrylhydrazyl
keywords: Antioxidant activities; Biosynthesis; Organo-selenium; Pseudomonas PT-8; Selenium rich exopolysaccharide