Analysis and optimization of against E.coli by fermented supernatant from two Lactobacillus

In this study, using E.coli as the indicator bacteria the antibacterial activity against E.coli of the fermented supernatant of Lactobacillus plantarum and Lactobacillus bulgaricus by the agar diffusion was investgated.Then, the effect of culture temperature, glucose concentration, pH and cultivating time on the antibacterial activity of the Lactobacillus plantarum were studied.The results showed that when Lactobacillus plantarum were incubated at 35℃, glucose concentration 8% and pH9, the antibacterial activity of its fermentation supernatant fluid was pretty good.Orthogonal test was used to analyze the optimum culture conditions for planting Latcobacillus.The optimum culture conditions for its antibacterial activity were estimated to be, cultivation temperature at 35℃, incubating for 36h, glucose concentration 8% and pH7, and the bacteriostatic circle was measured at (1.451±0.016) cm in diameter.In addition, the results of this study suggested that Lactobacillus bulgaricus had no bacteriostasis to E.coli.