SELECTION OF HIGH ACTIVITY β-GALACTOSIDASE BULGARICUS LACTOBACILLUS

Objective:In order to authenticate the bulgaria lactobacillus from which β galactosidase gene comes from and screen the bacterium which produces large quantity of β galactosidase.Methods:Gram stain and morphology,H 2O 2 enzyme,carbogydrates fermentation to produce acid and the litmus milk test were performed.By using X gal test and ONPG test,the β galactosidase activity quality and quantity were detected respectively.Results:Bulgaricus Lactobacillus 1 1408 and Bulgaricus Lactobacillus selected from the yoghourt were all Bulgaricus Lactobacilli,but the characters of Bulgaricus Lactobacillus 6032 had changed.Bulgaricus Lactobacillus 1 1480 and Bulgaricus Lactobacillus selected from the yoghourt appeared blue colour on the argar plate containing X gal.And Bulgaricus Lactobacillus 1 1480 produced high quality and large quantity of β galactosidase.Conclusion:Bulgaricus Lactobacillus selected by us could have been tamed during being used as the starter of the yoghourt.The characters of Bulgaricus Lactobacillus 1 1480 are consistent with the phenotypes in Bergeys manual of determinative bacteriology,and the β galactosidase activity is the best of these three bacteria.So the DNA of Bulgaricus Lactobacillus 1 1480 was utilized as the template in the following tests.