Screening of Lactic acid bacteria strains with high antibacterial activity from Douchi and it's research of bacteriostatic

Objective To screen Lactic acid bacteria strains with high inhibitory activity from Yunnan Douchi,analyze its mechanism of bacteria inhibition.Method Lactic acid bacteria strains were isolated from Yunnan traditional fermented Douchi using traditional techniques of pure culture.Their antibacterial activity were assayed by spot-on-lawn method.Forty strains were identified as Lactic acid bacteria.YM-4-3 strain was identified as Lactobacillus plantarum with high antibacterial activity.Analysis and antibacterial experiments were performed on the major inhibitory substances with HPLC and ultraviolet spectrophotometric methods.Result The strain YM-4-3 showed a wide antibacterial spectrum with ability to inhibit both Gram pasitive and negative bacteria.Conclusion It was preliminarily conjectured that the mechanism of bacteriostatic was organic acid as leader,then bacteriocin and other chemistry substances against them.