Isolation and gut benefit evaluations of Bifidobacterium adolescentis

• Main Authors: Lin, Zih -Jiun, 林姿君
• Other Authors: Chen, Yo -Chia
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/28621602113708532011

碩士 === 國立屏東科技大學 === 生物科技系所 === 104 === Bifidobacteriumis indigenous to the human intestine, where they preferentially colonise the colon. It plays important roles in the enhancement of immunity, in maintenance of intestinal microbial balance, and the prevention of bacteriuminfection in the gastrointestinal tract. Beta-glucosidase activities present in the microorganism act on glycoside, with potential health implications for the human host. This studyfiveisolatedB. adolescentisfrom the feces of adultswere examined theirby Gram stain, morphology, physiology, biochemical characterization, and carbohydrate metabolites.As shown in results, strain 3-30, strain 3-51, strain 3-55 showed their similar physiological characteristics to BifidobacteriuminGram positive, anaerobic,Y shape, negativeminus of catalase and cell oxidase testand API 20A.Their16S rDNAwere amplified by universal primers of Bifidobacteriumin PCR. Furthermore, species specific primers of B. adolescentis were also used to identified their genus. The isolatessimilarity in their16S rDNA and 16S-23Ssequences by phylogenyanalysisconfirmed for species identities.These results indicated that strain 3-30and strain 3-55are B.adolescentis, strain 3-51 may be B.breve.The culture broth, pellet and supernatantof all isolates influenced the growth of the Pseudomonas aeruginosa BCRC10261and demonstrated 17~26 mm inhibitory zones around the paper disks. Furthermore,the EPS of all isolates were purified from supernatant also influenced the growth of the P. aeruginosaand demonstrated 20 mm inhibitory zones around the paper disks. EPS stimulated the Caco-2 cells to produce IL-8(Interleukin-8) and the higher concentrations of EPS in 5 mg/L can increasedIL-8 levels for 31~180 pg/mL. Fructooligosaccharides was the effective carbohydrate source for the production of EPS in our isolates.The levels EPS productedby the isolates were ranging 5793.6~8691.4mg/L.These results indicated that EPS of all isolates are not only capable to influence the growth of P. aeruginosaby directly inhibitory but also stimulate of immune system of epithelial cell in the gut.The optimalactivityof beta-glucosidaseproduced by isolateswere1.17~1.35 U in 12 or 24 hours and 55˚C.The results showed that the isolates were hydrolysis of isoflavones glycosideby 57~99 % to aglycones, and carbohydrate were increased 3~79 %.These suggested thatβ-glucosidase of the isolates are capable to hydrolysis of isoflavones glycoside for enhancing absorption in the gut. Keywords: Bifidobacterium adolescentis、exopolysaccharides and glucosidase