State Key Laboratory of Microbial Technology, Institute of Marine Science and Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, 266237, China.
Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China.
Appl Microbiol Biotechnol. 2020 Jun;104(11):4863-4875. doi: 10.1007/s00253-020-10524-z. Epub 2020 Apr 13.
Although microbial exopolysaccharides (EPSs) are applied in different fields, no EPS has been used to protect human skin cells against UV-induced oxidative stress. The EPS produced by the Arctic bacterium Polaribacter sp. SM1127 has high moisture-retention ability and antioxidant activity, suggesting its good industrial potentials. In this study, we improved the EPS production of SM1127 and evaluated its protective effect on human dermal fibroblasts (HDFs) against UV-induced oxidative stress. With glucose as carbon source, the EPS yield was increased from 2.11 to 6.12 g/L by optimizing the fermentation conditions using response surface methodology. To lower the fermentation cost and decrease corrosive speed in stainless steel tanks, whole sugar, whose price is only 8% of that of glucose, was used to replace glucose and NaCl concentration was reduced to 4 g/L in the medium. With the optimized conditions, fed-batch fermentation in a 5-L bioreactor was conducted, and the EPS production reached 19.25 g/L, which represents the highest one reported for a polar microorganism. Moreover, SM1127 EPS could maintain the cell viability and integrity of HDFs under UV-B radiation, probably via decreasing intracellular reactive oxygen species level and increasing intracellular glutathione content and superoxide dismutase activity. Therefore, SM1127 EPS has significant protective effect on HDFs against UV-induced oxidative stress, suggesting its potential to be used in preventing photoaging and photocarcinogenesis. Altogether, this study lays a good foundation for the industrialization of SM1127 EPS, which has promising potential to be used in cosmetics and medical fields.
虽然微生物胞外多糖（EPS）被应用于不同领域，但尚未有 EPS 被用于保护人类皮肤细胞免受 UV 诱导的氧化应激。由北极细菌 Polaribacter sp. SM1127 产生的 EPS 具有高保湿能力和抗氧化活性，这表明其具有良好的工业潜力。在本研究中，我们提高了 SM1127 的 EPS 产量，并评估了其对人真皮成纤维细胞（HDFs）抵抗 UV 诱导的氧化应激的保护作用。以葡萄糖为碳源，通过响应面法优化发酵条件，EPS 产量从 2.11 增加到 6.12 g/L。为了降低发酵成本和减少不锈钢罐的腐蚀性速度，使用价格仅为葡萄糖的 8%的全糖替代葡萄糖，并将培养基中的 NaCl 浓度降低到 4 g/L。在优化条件下，在 5 L 生物反应器中进行分批补料发酵，EPS 产量达到 19.25 g/L，这是报道的极地微生物的最高产量。此外，SM1127 EPS 可以在 UV-B 辐射下维持 HDFs 的细胞活力和完整性，可能是通过降低细胞内活性氧水平、增加细胞内谷胱甘肽含量和超氧化物歧化酶活性来实现的。因此，SM1127 EPS 对 HDFs 抵抗 UV 诱导的氧化应激具有显著的保护作用，这表明其在预防光老化和光致癌发生方面具有潜在应用价值。总之，本研究为 SM1127 EPS 的工业化奠定了良好的基础，其在化妆品和医疗领域具有广阔的应用前景。
