Srinivash Moovendran, Krishnamoorthi Raman, Mahalingam Pambayan Ulagan, Malaikozhundan Balasubramanian
Department of Biology, The Gandhigram Rural Institute (Deemed to be University), Gandhigram, Dindigul 624302, Tamil Nadu, India.
Plant Pathology Division, Indian Cardamom Research Institute, Spices Board (Ministry of Commerce and Industry, Government of India), Myladumpara- 685553, Idukki, Kerala, India.
Int J Biol Macromol. 2023 Oct 1;250:126171. doi: 10.1016/j.ijbiomac.2023.126171. Epub 2023 Aug 7.
Naturally occurring biopolymers like exopolysaccharides (EPS) secreted by lactic acid bacteria (LAB) has gained significant attention as they are cost effective, renewable and safe. In order to prevent the rapid increase in antibiotic resistant bacteria, the EPS of LAB offers novel approach of targeting the antibiotic resistant pathogens by limiting their effects on environment. Accordingly, in this study, the production, purification, characterization and biological properties of exopolysaccharides from Lactococcus hircilactis strain CH4 and Lactobacillus delbrueckii strain GRIPUMSK were performed. The optimization of lactic acid bacterial strains for exopolysaccharide production was done by response surface methodology and changing the carbon sources in the growth media. The carbohydrate and protein of exopolysaccharide 1 were 79.7 % and 8.7 % respectively and exopolysaccharide 2 were 75.2 % and 9.3 % respectively. When compared with the commercial emulsifier sodium dodecyl sulfate, both the exopolysaccharides have shown good emulsifying activity. Both the exopolysaccharides were linear homo-polysaccharide as determined by Fourier transform infrared spectroscopy and Nuclear magnetic resonance spectra. Scanning electron microscopy showed that the exopolysaccharides were porous and capable of holding water. The exopolysaccharides were partially crystalline as confirmed by X-ray diffraction spectra. Exopolysaccharides from L. hircilactis and L. delbrueckii exhibited significant antimicrobial activity against H. pylori, S. flexneri, S. pyogenes, E. faecalis and C. albicans. Both the exopolysaccharides revealed significant 2,2-diphenyl-1-picrylhydrazyl and hydrogen peroxide scavenging ability with the IC value of 100 μg/ml and 80 μg/ml respectively. Exopolysaccharides from L. hircilactis and L. delbrueckii at 100 μg/ml showed significant anticancer activity on HT-29 cells with 58.4 % and 58.7 % respectively. These findings proved that exopolysaccharides from the two selected lactic acid bacterial strains could be explored as natural bioactive carbohydrate polymer for biomedical applications.
天然存在的生物聚合物，如乳酸菌（LAB）分泌的胞外多糖（EPS），因其具有成本效益、可再生且安全等特点而备受关注。为了防止抗生素抗性细菌的迅速增加，LAB的EPS提供了一种新方法，即通过限制其对环境的影响来靶向抗生素抗性病原体。因此，在本研究中，对来自乳球菌CH4菌株和德氏乳杆菌GRIPUMSK菌株的胞外多糖进行了生产、纯化、表征及生物学特性研究。通过响应面法和改变生长培养基中的碳源对用于胞外多糖生产的乳酸菌菌株进行了优化。胞外多糖1的碳水化合物和蛋白质含量分别为79.7%和8.7%，胞外多糖2的碳水化合物和蛋白质含量分别为75.2%和9.3%。与市售乳化剂十二烷基硫酸钠相比，两种胞外多糖均表现出良好的乳化活性。通过傅里叶变换红外光谱和核磁共振光谱测定，两种胞外多糖均为线性同多糖。扫描电子显微镜显示，胞外多糖具有多孔性且能够保持水分。X射线衍射光谱证实胞外多糖为部分结晶。来自乳球菌和德氏乳杆菌的胞外多糖对幽门螺杆菌、福氏志贺菌、化脓性链球菌、粪肠球菌和白色念珠菌表现出显著的抗菌活性。两种胞外多糖均显示出显著的2,2-二苯基-1-苦基肼自由基清除能力和过氧化氢清除能力，IC值分别为100μg/ml和80μg/ml。来自乳球菌和德氏乳杆菌的胞外多糖在浓度为100μg/ml时对HT-29细胞分别表现出58.4%和58.7%的显著抗癌活性。这些发现证明，从两种选定的乳酸菌菌株中提取的胞外多糖可作为天然生物活性碳水化合物聚合物用于生物医学应用。
