Xu Ziyin, Xu Lin, Chen Mei, Li Zhonghai
State Key Laboratory of Green Papermaking and Resource Recycling, School of Bioengineering, Shandong Provincial Key Laboratory of Microbial Engineering, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China.
Foods. 2025 Aug 12;14(16):2796. doi: 10.3390/foods14162796.
exhibits advantages such as strong thermotolerance, rapid growth rate, and high safety, making it an excellent host cell for the production of bio-based products. In this study, two exopolysaccharides, KE1 and KE2, were isolated from the fermentation broth of the strain KM-502, and their hydroxyl radical scavenging, DPPH scavenging, and Fe-reducing activities were evaluated. In vitro antioxidant assays demonstrated that exopolysaccharide KE2 exhibited superior antioxidant activity compared to KE1. The fermentation conditions were optimized using single-factor experiments followed by response surface methodology (RSM). The optimized fermentation process revealed that the most suitable fermentation medium consisted of 8% sucrose, 1.99% peptone, and 0.13% CaCl, while the optimal fermentation conditions were a medium volume of 74 mL in a 300 mL flask, pH 6.7, an inoculum size of 1.99%, a temperature of 30 °C, a shaking speed of 160 r/min, and a cultivation time of 96 h. After optimizing the fermentation conditions of KM-502, the exopolysaccharide (EPS) yield reached 5842.42 mg/L, representing a 22.77-fold increase compared to the yield before optimization. In summary, this study isolated exopolysaccharides KE1 and KE2 from KM-502. These exopolysaccharides demonstrated significant antioxidant activities, and the fermentation conditions for exopolysaccharide production were optimized. The findings of this study will facilitate the further development and utilization of exopolysaccharides from .
具有诸如耐热性强、生长速度快和安全性高等优点，使其成为生产生物基产品的优良宿主细胞。在本研究中，从菌株KM - 502的发酵液中分离出两种胞外多糖KE1和KE2，并评估了它们的羟基自由基清除、DPPH清除和铁还原活性。体外抗氧化试验表明，胞外多糖KE2比KE1表现出更强的抗氧化活性。采用单因素实验结合响应面法（RSM）对发酵条件进行了优化。优化后的发酵工艺表明，最合适的发酵培养基由8%蔗糖、1.99%蛋白胨和0.13%氯化钙组成，而最佳发酵条件为在300 mL烧瓶中培养基体积为74 mL、pH 6.7、接种量1.99%、温度30℃、振荡速度160 r/min和培养时间96 h。优化KM - 502的发酵条件后，胞外多糖（EPS）产量达到5842.42 mg/L，与优化前的产量相比提高了22.77倍。总之，本研究从KM - 502中分离出胞外多糖KE1和KE2。这些胞外多糖表现出显著的抗氧化活性，并优化了胞外多糖生产的发酵条件。本研究结果将有助于进一步开发和利用来自……的胞外多糖。
