Optimization of Extracellular Polysaccharide Substances from Lactic Acid Bacteria Isolated from Fermented Dairy Products

摘要

Background and Objective: The extracellular polysaccharide secreted by Lactic Acid Bacteria (LAB) has been used in the food industrydue to their viscosity, bio-thickening properties as well as immunomodulatory potentials. Due to the increase in the demand for EPS, thereis a need to study the production of extracellular polysaccharides produced by Lactic Acid Bacteria (LAB) under different productionconditions for optimum EPS production. Materials and Methods: Five EPS producing LAB isolated from fermented dairy products werecollected from the culture collection Centre, maintained in De Ma, Rogosa and Sharpe (MRS) broth and the EPS producing LAB weremolecularly characterized. Modified Exopolysaccharide Selection Medium (mESM) was used to produce the EPS. Results: The EPSproducers were molecularly characterized as Lactobacillus tucetti FASHADFF2, Lactobacillus delbrueckii FASHADYG2, Weissella sp.FASHADFF1, Weissella sp. FASHADWR2 and Leuconostoc mesenteroides FASHADWR1. The EPS produced by the five LAB strains rangedfrom 109.11-185.02 mg LG1. About 35EC and pH 5 supported the highest EPS production by the isolates. Glucose, sucrose, yeast extract,alanine and folic acid supported the highest EPS production. Conclusion: This study demonstrated that all the five LAB strains were EPSproducers and they were 99-100% molecularly related to the identified species of LAB. Optimizing the production of EPS by the LAB strainsyields a higher amount of EPS.