Isolation and Identification of Dextran-Producting Strain and Study of Fermentation Conditions

Abstract:

In this study,a dextran-producting strain T-L1,was isolated from kefir by by lactobacillus screening and dextran yeild analysis.Then strain T-L1 was identified as Leuconostoc mesenteroides by the morphological properties and 16S rRNA sequence.Furthermore,the single factor experiments and orthogonal experiments were adopted to optimize the nutrients and environmental conditions for increasing production of dextran by strain T-L1.The optimum conditions for dextran production listed as follows: the initial pH 6.5,the fermentation temperature 28 ℃,the inoculation volume 5% and the fermentation time 24 h.Under the optimum condtions,the titer of dextran was achieved at 30.12 g/L,higher 41.08% than that of the control.