Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Harbin, Heilongjiang 150500, People's Republic of China; Laboratory of Microbiology, College of Life Science, Heilongjiang University, Harbin, Heilongjiang 150080, People's Republic of China.
Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Harbin, Heilongjiang 150500, People's Republic of China; Laboratory of Microbiology, College of Life Science, Heilongjiang University, Harbin, Heilongjiang 150080, People's Republic of China.
Int J Biol Macromol. 2019 Oct 15;139:1224-1231. doi: 10.1016/j.ijbiomac.2019.08.114. Epub 2019 Aug 14.
An exopolysaccharide (EPS)-producing bacterium was isolated from the homemade fermentation product of hami melon (Cucumis melo var. saccharinus) and identified as Leuconostoc lactis L2 mainly based on 16S rDNA sequence analysis and the API 50 CHL test. The monosaccharide composition of Leu. lactis L2 EPS was determined to be glucose by gas chromatography (GC), and its molecular weight was 3.7 × 10 kDa by high-performance size exclusion chromatography (HPSEC). The EPS microscopic characteristics were compact, branched and tubular under scanning electron microscopy (SEM). Atomic force microscopy (AFM) showed a smooth and consistent polymeric matrix. The EPS was a linear polymer composed of α-(1 → 6)-linked D-pyranose residues, based on the Fourier transform infrared (FT-IR), H, C nuclear magnetic resonance (NMR) and heteronuclear single quantum coherence (HSQC) spectra. This EPS exhibited a high water solubility index (WSI) and water holding capacity (WHC) (91.90 ± 2.45% and 509.45 ± 28.59%, respectively), as well as good emulsifying properties with many organic solvents. These results collectively suggest the applicable potential of this EPS in the food, feed and pharmaceutical fields.
从哈密瓜（Cucumis melo var. saccharinus）自制发酵产品中分离到一株产胞外多糖（EPS）的细菌，主要基于 16S rDNA 序列分析和 API 50 CHL 试验，将其鉴定为乳球菌（Leuconostoc lactis）L2。通过气相色谱（GC）确定 Leu. lactis L2 EPS 的单糖组成为葡萄糖，通过高效体积排除色谱（HPSEC）确定其分子量为 3.7×10 kDa。扫描电子显微镜（SEM）下 EPS 的微观特征为紧密、分支和管状。原子力显微镜（AFM）显示出光滑一致的聚合基质。基于傅里叶变换红外（FT-IR）、H、C 核磁共振（NMR）和异核单量子相干（HSQC）谱，EPS 是一种由α-（1→6）-连接的 D-吡喃糖残基组成的线性聚合物。该 EPS 具有较高的水溶性指数（WSI）和持水能力（WHC）（分别为 91.90±2.45%和 509.45±28.59%），以及与多种有机溶剂良好的乳化性能。这些结果共同表明该 EPS 在食品、饲料和制药领域具有应用潜力。
