Research On Excellent Lactic Acid Bacteria Isolation And Identification And Its Biological Characteristics

Lactic acid bacteria,a type of probiotics with important physiological function, isextensively applied in food industry for promoting consumer’s health. The generation ofexcellent traits of Lactic acid bacteria is very significant in the study of lactic acid bacteriaand their application in the food industry.In the present research, Lactic acid bacteria was successfully isolated from corn silageand20single colonies were selected for further training. The strains identification ofselected bacteria were performed with the surface morphology,and physiological test,16SrRNA gene sequencing analysis and phylogenetic trees. Excellent trait strains werescreened out by measuring the acid production rate,growth rate and biochemical test.The identification of20single colonies were:15strains Lactobacillus plantarum,2strains Lactobacillus coryniformis,1strain Lactobacillus brevis,1strain Lactobacilluscasei and1strain Weissella paramesenteroides respectively.In the determination of the rate of acid production, it was found that the pH values ofmost strains start to decrease after inoculation and tended to be stable after18h, and therapid decline of pH values were observed during4~10h. However, the pH value ofLactobacillus brevis culture started to decrease after14h and tended to be stable after18h.The determination of growth rates show that most strains started to grow after2h andfastest growth was observed in2~8h, and the culture tended to be stable after8h offollowing slow growth. However, the Lactobacillus brevis grew slowly during the initial12h and started to a rapidly logarithmic growth after12h, and another slow growth wasobserved during18~24h. By comparing these two curves, the No.3,7and16strains werescreened out as the superior traits strains, namely Lactobacillus plantarum。...