Center of Agro-food Technology, Northeast Agricultural Research Center of China, No. 1363 Cai-Yu Street, Changchun, Jilin Province, 130033, PR China.
J Biosci Bioeng. 2010 Jul;110(1):53-7. doi: 10.1016/j.jbiosc.2009.12.010. Epub 2010 Jan 27.
Exopolysaccharides (EPSs) produced by lactic acid bacteria (LAB) play an important role in the improvement of the physical properties of fermented dairy products. To find EPS-producing LAB strains with potential industrial applications, a Lactobacillus rhamnosus strain, L. rhamnosus JAAS8, that is capable of producing two forms of EPS when grown in MRS broth or semi-defined medium with glucose as a carbon source was isolated and identified from Chinese sauerkraut. The capsular-polysaccharide (CPS) present surrounding the bacterial surface of L. rhamnosus JAAS8 was observed by both optical microscopy and transmission electron microscopy. The slime-polysaccharide (SPS) present in the growth medium was produced mainly during the exponential growth phase, while the CPS was produced only in fermentation. Monosaccharide analysis of the purified polysaccharide samples showed that the CPS was composed of galactose and N-acetylglucosamine in a molar ratio of 5:1, and the SPS was composed of galactose, glucose and N-acetylglucosamine in a molar ratio of 4:1:1. The use of L. rhamnosus JAAS8 could be considered for potential applications in the dairy industry to improve the rheological properties of fermented milk products by increasing their water-holding capacity and viscosity.
乳酸菌(LAB)产生的胞外多糖(EPS)在改善发酵乳制品的物理性质方面发挥着重要作用。为了寻找具有潜在工业应用价值的产 EPS 的 LAB 菌株,从中国酸菜中分离并鉴定出一株能够在 MRS 肉汤或以葡萄糖为碳源的半合成培养基中生长时产生两种形式 EPS 的鼠李糖乳杆菌(Lactobacillus rhamnosus)JAAS8。通过光学显微镜和透射电子显微镜观察到 L. rhamnosus JAAS8 细菌表面周围存在荚膜多糖(CPS)。在生长培养基中存在的粘液多糖(SPS)主要在指数生长期产生,而 CPS 仅在发酵过程中产生。对纯化多糖样品的单糖分析表明,CPS 由半乳糖和 N-乙酰葡萄糖胺以 5:1 的摩尔比组成,SPS 由半乳糖、葡萄糖和 N-乙酰葡萄糖胺以 4:1:1 的摩尔比组成。可以考虑使用 L. rhamnosus JAAS8 在乳制品工业中应用,通过增加其持水能力和黏度来改善发酵乳产品的流变学性质。