Screening,identification And Biological Characteristics Of Potential Hypoglycemic Strains

In order to explore the hypoglycemic effect of strains and the development of healthy products,this study was carried out to screen and identify 24 strains of lactic acid bacteria,39 strains of yeasts,and 41 strains of bacillus isolated in the laboratory for the production of?-Glucosidase inhibitor and dipeptidyl peptidase(DPP-?)inhibitor.And research of the biological characteristics and antioxidant capacity of strains that can simultaneously inhibit the activities of?-Glucosidase and DPP-?.A strain of lactic acid bacteria MW1with better comprehensive characteristics was screened for the optimization of growth conditions and explore the effect on hypoglycemic activity.The results showed that:Preliminary screening of DPP-? inhibitor producing strains,7 strains of lactic acid bacteria,6 strains of yeasts and 5 strains of bacillus that can hydrolyze milk protein were screened out;Screening of?-Glucosidase inhibitor producing strains,there were 21 strains of lactic acid bacteria,13 strains of yeast and 18 strains of bacillus with better?-amylase inhibition activities.The strains were re-screened and screened out lactic acid bacteria MK2a,MF4,MW1,MH2,MK3,MF2 and yeast YK1,YM5,YW1,YW5a,YM2a as well as Bacillus LK5a,LW2a,LF1,LF6 which can simultaneously inhibited?-Glucosidase and DPP-? activities.According to molecular biology analysis,lactic acid bacteria MW1a,MK2a,MF4,MK3,MF2,MW1 are Lactobacillus salivarius strains,MH2 is Enterococuus faecium strain;Yeast YH4 is Kluyveromyces marxianus strain,YK1,YM2a,YW5a,YW1are Pichia sp.;Bacillus LF1 is Bacillus licheniformis strain,LK5a and LF6 are Bacillus subtilis strain,LW2a is Bacillus amyloliquefaciens strain.Through the study of biological characteristics and antioxidant capacity,excellent strains MW1 has good tolerance to acidic environment of p H 2.5,p H 3.0,p H 3.5 and 0.3%bile salt environment.After simulating the operation of artificial gastric and intestinal fluid,the higher survival rate was 80.68%,And it had good tolerance to 2%and 4%Na Cl hypotonic environment.The results of the antioxidant test showed that the metabolites and intracellular substances of MW1 have different degrees of scavenging as well as reducing ability to DPPH·free radicals,·OH~-free radicals,and ABTS~+free radicals.Single factor and orthogonal experiments were used to study the effect of growth conditions on the hypoglycemic activity of MW1.The results showed that MW1 has the best hypogluycemic ability with 31?growth temperature,7.0 initial growth p H and 3.0%inoculum size.