乳酸菌菌株分离及益生效果评价

Isolation of Lactic Acid Bacterial Strains and Evaluation of Probiotic Effects

乳酸菌与我们的生活密切相关,是生物体内重要的细菌群落。乳酸菌在人体内发挥着重要的功能,其生长和繁殖的过程能够产生很多酸性胞外产物,这些产物能够抑制病原微生物生长,同时,这些酸性物质具有抗氧化、提高机体免疫力、降胆固醇、降血糖等多种生物活性功能。该研究基于此,通过对传统酸奶和市场上活性菌粉进行分离,并使用形态学和分子生物学对其进行鉴定,一共鉴定出5个乳酸菌物种,分别是Lactobacillus plantarum,L.paracasei,L.rhamnosus,L.rhamnosus和L.casei。选择Lactobacillus plantarum,L.paracasei,L.rhamnosus,L.rhamnosus和L.casei 5个不同的物种的产酸能力、胆盐的耐受性、低温耐受性和抗氧化活性进行研究。研究结果表明,Lactobacillus rhamnosus的产酸能力比其他4种乳酸菌弱;L.casei受胆盐的影响小,能够在高浓度的胆盐条件下繁殖;在-20℃的条件下存放10 d,L.rhamnosus的乳酸菌活菌数保持了较高的活性,L.paracasei和L.casei的菌株失活较为明显。

Lactic acid bacteria are closely related to our lives and are an important bacterial community in the organisms.Lactic acid bacteria play an important role in the human body.During the process of growth and reproduction,they can produce many acidic extracellular products,which can inhibit the growth of pathogenic microorganisms.At the same time,these acidic substances have a variety of bioactive functions,such as antioxidation,improving body immunity,and reducing cholesterol and blood sugar.Based on this,by separating traditional yogurt and active bacterial powder on the market,identifying them by morphology and molecular biology,a total of five lactic acid bacterial species are identified,namely Lactobacillus plantarum,L.paracasei,L.rhamnosus,L.rhamnosus and L.casei.The acid production capacity,bile salt tolerance,low temperature tolerance and antioxidant activity of five different species such as Lactobacillus plantarum,L.paracasei,L.rhamnosus,L.rhamnosus and L.casei are selected to study.The results of this study show that the acid production capacity of Lactobacillus rhamnosus is weaker than that of the other four lactic acid bacteria;L.casei is less affected by bile salts and can reproduce under high concentration of bile salts;when being stored at-20℃for 10 days,L.rhamnosus maintains a high number of active lactic acid bacteria,and the inactivation of L.paracasei and L.casei is more obvious.