摘要
An exopolysaccharides (EPS) producing strain was isolated from Yunnan Puer tea. This strain was defined as Bacillus amyloliquefaciens DMBA-K4 by 16S rDNA. Single factor trials and response surface tests were performed to optimize its EPS yield, and its in vitro antioxidant activity was also investigated. The optimal fermentation conditions were as follow: the culture medium consisted of 4 g / L sucrose, 5 g / L tryptone, 10 g / L yeast, 5 g / L NaCl, pH 7. 6, inoculator amount of 3. 10% and fermented for 18 h. Under these conditions, the maximal yields of EPS increased by 155. 7% and reached 171. 31mg / L. In vitro antioxidant results showed that EPS had strong antioxidant activity. When the concentration of EPS was 5 mg / mL, the scavenging rate of DPPH free radical and ·OH was 78. 60% and 75. 47%, respectively. The research provide theoretical support to EPS industrialization and widen the utilization prospect of novel bio-polysaccharide. ? 2020 Authors.
- 单位