Fermentation conditions optimization, purification, and antioxidant activity of exopolysaccharides obtained from the plant growth-promoting endophytic actinobacterium Glutamicibacter halophytocola KLBMP 5180

• Published in: International journal of biological macromolecules 2020-06, Vol.153, p.1176-1185
• Main Authors: Xiong, You-Wei, Ju, Xiu-Yun, Li, Xue-Wei, Gong, Yuan, Xu, Ming-Jie, Zhang, Chun-Mei, Yuan, Bo, Lv, Zuo-Peng, Qin, Sheng
• Format: Article
• Language: English
• Subjects: Antioxidant activity; Antioxidants - chemistry; Antioxidants - isolation & purification; Antioxidants - metabolism; Antioxidants - pharmacology; Biotechnology; Exopolysaccharides; Fermentation; Glutamicibacter halophytocola; Micrococcaceae - drug effects; Micrococcaceae - growth & development; Micrococcaceae - metabolism; Molecular Weight; Monosaccharides - analysis; Nutrients - pharmacology; Polysaccharides, Bacterial - biosynthesis; Polysaccharides, Bacterial - chemistry; Polysaccharides, Bacterial - isolation & purification; Polysaccharides, Bacterial - pharmacology; Salts - pharmacology
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2019.10.247

[Display omitted] •The EPS yield of Glutamicibacter halophytocola KLBMP 5180 was increased to 2.89 g/L after RSM.•Two purified EPSs components were further obtained from G. halophytocola KLBMP 5180.•Molecular weight of 5180EPS-1 and 5180EPS-2 was found as 58.9 kDa and 10.5 kDa, respectively.•The two EPSs had certain antioxidant activities. In this study, an endophytic actinobacterium Glutamicibacter halophytocola KLBMP 5180, was investigated for the production and antioxidant activity of exopolysaccharides (EPSs). First, the suitable fermentation time, temperature, inoculation volume, pH value, and the carbon and nitrogen sources for EPSs production were obtained using the one variable at a time method (OVAT). Then, a central composition design was used for fermentation conditions optimization to obtain the maximum EPS yield. The optimal medium and condition were as follows: 100 mL broth in 250 mL Erlenmeyer flasks, including 3.65 g/L maltose, 9.88 g/L malt extract, 3.40 g/L yeast extract, 1.41 g/L MnCl2, pH 7.5, culture temperature 28 °C, and 200 rpm for 7 days, which increased the yield of EPSs to 2.89 g/L. Two purified EPSs, 5180EPS-1 (MW 58.9 kDa) and 5180EPS-2 (10.5 kDa), comprising rhamnose, galacturonic acid, glucose, glucuronic acid, xylose, and arabinose, were obtained for chemical analysis and antioxidant evaluation. The scavenging ability and reducing power of the superoxide anion and hydroxyl radicals demonstrated the moderate in vitro antioxidant activities of the two EPSs, thus indicating their potential to be a new source of natural antioxidants. However, further structure elucidation and functional studies need to be continued.