Evaluating the antimicrobial properties of Lactobacillus brevis isolated from whole barley sourdough

In this study after molecular identification of dominant Lactobacillus isolated from whole barley sourdough, antimicrobial properties of the isolate and it’s cell free culture filtrate (CCF) as native (natural pH) and neutralized obtained from logarithmic and stationary phases against some of food borne bacteria and fungi were investigated. For statistical analysis a completely randomized design with factorial arrangement was used. By sequencing of specific PCR products, mentioned isolate was identified as Lactobacillus brevis. For evaluation of antibacterial properties of the isolate, disc diffusion and microdilution and also for antifungal study, overlay and agar spore spot methods were used. Based on the results of disc diffusion, the highest and lowest antagonistic effects of L. brevis were observed against Bacillus subtilis and Escherichia coli, respectively. According to microdilution results, the highest effect of CCF on indicator bacteria was also observed in native CCF obtained from L. brevis logarithmic phase which reduced 79.55% of B. subtilis population. Furthermore, antifungal activity of L. brevis against Aspergillus flavus and Aspergillus niger was confirmed based on results of overlay method. The antifungal activity of the isolate was not different significantly (α