Bergmaier D, Lacroix C, Guadalupe Macedo M, Champagne C P
Dairy Research Centre STELA, Pavilion Paul Comtois, Université Laval, Québec, PQ, Canada.
Appl Microbiol Biotechnol. 2001 Oct;57(3):401-6. doi: 10.1007/s002530100764.
A new method to remove simple carbohydrates from culture broth prior to the quantification of exopolysaccharides (EPS) was developed and validated for the EPS-producing strain, Lactobacillus rhamnosus RW-9595M. This method uses ultrafiltration (UF) in stirred cells followed by polysaccharide detection in the retentate by the phenol-sulfuric acid method. The UF method was compared with a conventional method based on ethanol extraction, dialysis, protein removal by trichloroacetic acid (TCA) and freeze-drying. EPS production during pH-controlled batch fermentations in basal minimum medium, whey permeate (WP). and whey permeate supplemented with yeast extract, minerals and Tween-80 (SWP) was determined by the new UF and conventional methods. EPS recovery by the new method ranged from 83% to 104% for EPS added in the concentration range 40-1,500 mg/l in 0.1 M NaCl solution or culture medium. The UF method was rapid (8 h), accurate and simple, and required only a small sample volume (1-5 ml). A very high maximum EPS production was measured in SWP by both the UF and conventional methods (1,718 and 1,755 mg/l).
开发了一种在定量胞外多糖（EPS）之前从培养液中去除单糖的新方法，并对产EPS的菌株鼠李糖乳杆菌RW-9595M进行了验证。该方法在搅拌池中使用超滤（UF），然后通过苯酚-硫酸法检测截留物中的多糖。将超滤法与基于乙醇萃取、透析、用三氯乙酸（TCA）去除蛋白质和冷冻干燥的传统方法进行了比较。通过新的超滤法和传统方法测定了在基础最低培养基、乳清渗透液（WP）以及添加了酵母提取物、矿物质和吐温80的乳清渗透液（SWP）中进行pH控制的分批发酵过程中的EPS产量。对于在0.1 M NaCl溶液或培养基中添加浓度范围为40-1500 mg/l的EPS，新方法的EPS回收率在83%至104%之间。超滤法快速（8小时）、准确且简单，仅需少量样品体积（1-5 ml）。通过超滤法和传统方法在SWP中均测得非常高的最大EPS产量（分别为1718和1755 mg/l）。
