The Study of Characteristics and Probiotic Potentials ofLactobacillus isolates

• Main Authors: YANG,YUEH-CHIN, 楊月欽
• Other Authors: TANG,HUANG-JEN
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/kqz85p

碩士 === 嘉南藥理大學 === 保健營養系 === 106 === Probiotics are commonly found in the intestinal and genitourinary tracts of humans and animals. They can produce a variety of acidic metabolites such as lactic acid, acetic acid and other substances, making its living environment is not conducive to the growth of other microorganisms. And several antibacterial substances such as bacteriocin, hydrogen peroxide (H2O2) and reuterin can be produced. Because they have the effect of maintaining the health of the host but does not harm the host. Therefore, the US Food and Drug Administration (FDA) defines lactic acid bacteria (LAB) as generally recognized as safe (GRAS) microorganisms. Lactobacillus spp. is the most important genus. Lactic acid bacteria are also one of the most commonly used health foods. However, in addition to having a bacteriostatic capacity, good intestinal lactic acid bacteria must be able to pass through the harsh environment of the gastrointestinal tract. In this study, the main purpose is to use in vitro models to simulate the environmental challenges that lactic acid bacteria must face when passing through the gastrointestinal tract. And preliminary tests on the inhibition of Gram-positive bacteria and negative bacteria. In order to find useful probiotics that can be used in the human body in the future. In this study, the tolerance ability of 57 strains of 8 Lactobacillus strains was tested with 3.5 mg/ml pepsin in pH 2.5 environment. Then test whether the strain can tolerate gastric acid (pH 3). And 0.3% Oxgall was used to simulate the intestine environment. Finally, we used the well-diffusion assays to test whether the culture supernatant of Lactobacillus had the effect of inhibiting bacteria. The results showed that 32 strains (56.1%) of Lactobacillus were reduced by less than one log after incubation with 3.5 mg/ml pepsin for four hours. 19 strains (33.3%) were completely suppressed. For the pH 3 environment, 56 strains (98.2%) can tolerate and only less than one logarithm reduction. There were also 56 strains (98.2%) survived in 0.3% bile salts, reduced less than one log reduction. In the antibacterial test for Staphylococcus aureus ATCC 29213, there were 45 strains (78.9%) with inhibition zone greater than 15 mm. For Salmonella typhimurium BCRC 14193, 54 strains (94.7%) have a greater than 15 mm inhibition zone. The conclusion, in this study, we found that some strains have the potential to become probiotics in the gut. Follow-up animal experiments can be performed to verify the actual effect of living body.