Yu You-Jin, Chen Zhiyang, Chen Po Ting, Ng I-Son
Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
Department of Chemical and Biochemical Engineering, Xiamen University, Xiamen 361005, China.
J Biosci Bioeng. 2018 Dec;126(6):769-777. doi: 10.1016/j.jbiosc.2018.05.028. Epub 2018 Jul 2.
Weissella cibaria 27 (W27) is a new lactic acid bacterium which has been screened from kimchi, and is important in diary fermentation. This is first-attempt to understand the effects of sucrose and achieve the highest exopolysaccharide (EPS) productivity from W27. The metabolic compounds of lactic acid, acetic acid and ethanol are at similar levels when the cultures with glucose or lactose; except for EPS is significantly increased up to 24.8 g/L with 60 g/L of sucrose. Scanning electron microscopy (SEM) results reveal cell length changing shorter after sucrose addition. By Taguchi's approach, an L9 orthogonal array was adopted to evaluate the effects of culture were ranked according to the EPS production as temperature > time > initial pH, in which optimal conditions were at 22°C and pH 6.2 for 24 h. The major composition of EPS is dextran of α-1,6 glycosidic linkage with molecular weight of 1.2 x 10 Da by nuclear magnetic resonance (NMR) and high-performance size-exclusion chromatography (HPSEC) analysis. The surface property of W27 induced by sucrose is become more hydrophobic to better inhibit bacteria. The simple cultural approach for this new dextran producing strain, W27, has potential in the food, feed, antibacterial agent, and cosmetic industry.
魏斯氏菌27（W27）是从泡菜中筛选出的一种新型乳酸菌，在乳制品发酵中具有重要作用。这是首次尝试了解蔗糖的影响，并使W27实现最高的胞外多糖（EPS）产量。当培养物中含有葡萄糖或乳糖时，乳酸、乙酸和乙醇的代谢化合物水平相似；但在添加60 g/L蔗糖时，EPS显著增加至24.8 g/L。扫描电子显微镜（SEM）结果显示，添加蔗糖后细胞长度变短。通过田口方法，采用L9正交表评估培养条件的影响，根据EPS产量对其进行排序为温度>时间>初始pH，其中最佳条件为22°C、pH 6.2、培养24小时。通过核磁共振（NMR）和高效尺寸排阻色谱（HPSEC）分析，EPS的主要成分是α-1,6糖苷键的葡聚糖，分子量为1.2×10 Da。蔗糖诱导的W27表面性质变得更疏水，从而能更好地抑制细菌。这种生产葡聚糖的新菌株W27的简单培养方法在食品、饲料、抗菌剂和化妆品行业具有潜力。
