Differential β-glucosidase Activities of Lactic Acid Bacteria on Daidzin and Genistin

• Main Authors: Hsu, Yupin, 許郁苹
• Other Authors: Wang, Sungyuan
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/25763271060640139499

碩士 === 實踐大學 === 食品營養與保健生技學系碩士班 === 99 === 　The present study was aiming to screen the lactic acid bacteria (LAB) strains with high β-glucosidase activity, concurrently with isoflavone glucoside hydrolysis activities, to assay the correlation of both activities of the screened LAB strains. Feces sample was collected from a six-year-old vegetarian child. After screening and pure culture by MRS broth containing soy isoflavones, fifteen strains with both high β-glucosidase and isoflavone glycoside hydrolysis activities were obtained, and 14 putative LABs were identified by gram stain and catalase test. Simultaneous in vitro analysis of β-glucosidase activities and isoflavone glycoside hydrolysis efficiencies test, revealed a positive correlation between both activities for these putative LABs. 　Three strains – A150, A169 and A260 – with the higher activities for β-glucosidase and isoflavone glycoside hydrolysis shown to have a significant differential glycoside hydrolysis efficiencies and were selected for species identification. Both phenotypic and genotypic identification were conducted by using API 50 CHL bacteria species identification kit and sequence analysis for 16S ribosomal RNA gene. genotypic analysis found that strains A150 and A169 are highly similar with that of Enterococcus faecium and identified as Enterococcus faecium Apple_150 and Enterococcus faecium Apple_169, and strain A260 is highly similar with that of Lactobacillus mucosae and given as Lactobacillus mucosae Apple_260. Taken together, we concluded that the LABs we screened (1) appeared to have different β-glucosidase activities and isoflavone glycosides hydrolysis efficiencies, (2) shown to have a positive correlation between both β-glucosidase activities and isoflavone glycosides hydrolysis efficiencies, and (3) have significant differential hydrolysis efficiencies on daidzin and genistin glucoside.