Sharma Kanika, Sharma Nivedita, Handa Shweta, Pathania Shruti
Microbiology Research Laboratory, Department of Basic Sciences, Dr Y S Parmar University of Horticulture and Forestry, Nauni, Solan, HP, 173230, India.
J Genet Eng Biotechnol. 2020 Oct 2;18(1):56. doi: 10.1186/s43141-020-00063-5.
Microbial origin polysaccharides have gained popularity due to lesser toxicity, better degradability and selectivity as compared to their synthetic counterparts and can be used as emulsifier, stabilizer, thickener, texturizer, flocculating and gelling agent. Here main emphasis on exopolysaccharide production from potential lactic acid bacteria that has GRAS status.
This work was aimed at isolating, purifying and characterizing an extracellular polysaccharide (EPS) produced by a foodgrade lactic acid bacteria Lactobacillus paraplantarum KM1. L. paraplantarum KM1 was isolated from human milk and identified by conventional and molecular techniques. The 16S rRNA sequence of the isolate was registered in National Centre for Biotechnology Information (NCBI) under accession number KX671558. L. paraplantarum KM1 was found to produce EPSs in lactose containing MRS medium, and the maximum yield (47.4 mg/ml) was achieved after 32-h incubation. As evident from TLC and HPLC analyses, the polysaccharide was found to be a heteropolymer-containing glucose, galactose and mannose as main sugars. Different oligosaccharides namely hexoses were obtained after partial hydrolysis of the polymer using MALDI-ToF-MS. The total molecular weight of all polysaccharides present was 348.7 kDa with 100 °C thermal stability as well as water soluble in nature. Cell cytotoxicity revealed that the purified EPS was safe for consumption; thus, it can be used in various food industries as emulsifying and texture agent.
The present study highlighted that exopolysaccharides could be harnessed to improve food products in terms of texture, emulsifying agents, pharmaceutical industry (antioxidants, antitumour, anti-inflammatory and antiviral agents) and as safety purposes.
与合成多糖相比，微生物来源的多糖因其较低的毒性、更好的降解性和选择性而受到欢迎，可作为乳化剂、稳定剂、增稠剂、质构剂、絮凝剂和胶凝剂。这里主要强调从具有公认安全（GRAS）地位的潜在乳酸菌中生产胞外多糖。
本研究旨在分离、纯化和表征由食品级乳酸菌植物源副干酪乳杆菌KM1产生的胞外多糖（EPS）。植物源副干酪乳杆菌KM1从人乳中分离得到，并通过传统和分子技术进行鉴定。该分离株的16S rRNA序列已在国家生物技术信息中心（NCBI）注册，登录号为KX671558。发现植物源副干酪乳杆菌KM1在含有乳糖的MRS培养基中产生EPS，培养32小时后产量最高（47.4毫克/毫升）。从薄层色谱（TLC）和高效液相色谱（HPLC）分析可以看出，该多糖是一种含有葡萄糖、半乳糖和甘露糖作为主要糖类的杂聚物。使用基质辅助激光解吸电离飞行时间质谱（MALDI-ToF-MS）对聚合物进行部分水解后，得到了不同的低聚糖，即己糖。所有存在的多糖的总分子量为348.7 kDa，具有100°C的热稳定性且在水中可溶。细胞毒性试验表明，纯化后的EPS食用安全；因此，它可作为乳化剂和质构剂用于各种食品工业。
本研究强调，胞外多糖可用于改善食品的质地、作为乳化剂、制药工业（抗氧化剂、抗肿瘤、抗炎和抗病毒剂）以及用于安全目的。
