A new extracellular polysaccharide (EPS-I) isolated and purified from Z_ 222 ,a strain of Lactic acid bacteria has been investigated. Sugar composition analysis,methylation analysis and 1H NMR and 13 C NM...A new extracellular polysaccharide (EPS-I) isolated and purified from Z_ 222 ,a strain of Lactic acid bacteria has been investigated. Sugar composition analysis,methylation analysis and 1H NMR and 13 C NMR spectroscopy reveal that the EPS-I is composed of a pentasaccharide repeating unit. The sequence of sugar residue was determined by using two-dimensional NMR spectroscopy,including heteronuclear multiple-bond correlation (HMBC) and nuclear overhauser effect spectroscopy (NOESY).展开更多
The influencing factors of extracellular polysac-charide(EPS)produced from a strain of lactic acid bacteria(LAB L15)were studied by using the phenol-H2SO4 method.It was demonstrated that the strain produced EPS at the...The influencing factors of extracellular polysac-charide(EPS)produced from a strain of lactic acid bacteria(LAB L15)were studied by using the phenol-H2SO4 method.It was demonstrated that the strain produced EPS at the most amount when it was incubated for 40-48 h and when the pH value was 4 under 30℃.Glucose was the most suitable carbon source for LAB-producing EPS.The rough EPS was obtained from L15 culture after centrifugation,dialysis,deprotein,decoloration,and ethanol-precipitation.The sample was at least composed of two polysaccharides that were completely different in molecular weight and the amount.The purified EPS was passed through the SephadexG-200 column and it showed that it was a sample purified by thin layer chromatography.展开更多
从生水牛乳中筛选出两株高产胞外多糖(EPS)的乳酸菌株LB2、LB7,经MRS肉汤培养基发酵后,菌液中的胞外多糖(EPS)产量分别达135 mg/L、148 mg/L,通过形态学、生理生化特征、API细菌鉴定系统、16S r RNA序列分析,鉴定出菌株LB2为植物乳杆菌(...从生水牛乳中筛选出两株高产胞外多糖(EPS)的乳酸菌株LB2、LB7,经MRS肉汤培养基发酵后,菌液中的胞外多糖(EPS)产量分别达135 mg/L、148 mg/L,通过形态学、生理生化特征、API细菌鉴定系统、16S r RNA序列分析,鉴定出菌株LB2为植物乳杆菌(Lactobacillus plantarum),LB7为类肠膜魏斯氏菌(Weissella paramesenteroides)。将其应用到水牛乳酸奶的发酵中,结果表明,植物乳杆菌LB2和类肠膜魏斯氏菌LB7均可用来发酵水牛乳酸奶,且能有效增加酸奶的黏度和胞外多糖产量,其黏度和EPS产量分别为4 050 m Pa·s和149 mg/L。展开更多
文摘A new extracellular polysaccharide (EPS-I) isolated and purified from Z_ 222 ,a strain of Lactic acid bacteria has been investigated. Sugar composition analysis,methylation analysis and 1H NMR and 13 C NMR spectroscopy reveal that the EPS-I is composed of a pentasaccharide repeating unit. The sequence of sugar residue was determined by using two-dimensional NMR spectroscopy,including heteronuclear multiple-bond correlation (HMBC) and nuclear overhauser effect spectroscopy (NOESY).
文摘The influencing factors of extracellular polysac-charide(EPS)produced from a strain of lactic acid bacteria(LAB L15)were studied by using the phenol-H2SO4 method.It was demonstrated that the strain produced EPS at the most amount when it was incubated for 40-48 h and when the pH value was 4 under 30℃.Glucose was the most suitable carbon source for LAB-producing EPS.The rough EPS was obtained from L15 culture after centrifugation,dialysis,deprotein,decoloration,and ethanol-precipitation.The sample was at least composed of two polysaccharides that were completely different in molecular weight and the amount.The purified EPS was passed through the SephadexG-200 column and it showed that it was a sample purified by thin layer chromatography.