Investigation of technological and antimicrobial characteristics of Lactobacillus brevis gp104 from Khikki cheese

Lactic acid bacteria have been used as a starter culture to produce fermented dairy products. Identifying and studying the technological and antimicrobial properties of these bacteria can enable their industrial applications. The aim of this study was to investigate the technological and antimicrobial characteristics of Lactobacillus brevis isolated from Khikki cheese. For this purpose, after Gram-staining and catalase test, molecular identification of the desired strain was performed using FYM27 and R1492 universal primers. Various technological characteristics of this strain such as exopolysaccharide production, proteolytic activity, lipolytic activity, acid production, survival under refrigerator conditions and its autolytic activity were examined. The antimicrobial activity was measured using “Lawn on the spot” method on food borne pathogens. The results showed that the strain belongs to L. brevis gp104. This strain also had ability to produce exopolysaccharide as a secondary metabolite; although it did not show proteolytic and lipolytic activity. Lactobacillus brevis reached pH = 4.6 at 15 °C after 72 h. This time was 48 and 24 h for 24 and 37 °C, respectively. The results showed that on the seventh day of its storage in refrigerator, the survival of the strain was approximately equal to the initial inoculated amount, but after 14 days, 1.5 Log CFU/ml and after 21 days, about 2 Log CFU/ml decreased in its number. In addition, the autolytic activity of Lactobacillus brevis was calculated to be 53%. The inhibition zone diameter for Enterobacter aerogenes, Salmonella typhi, Staphylococcus epidermidis and Listeria innocua was 11.30, 10.10, 22.40 and 19.50 mm, respectively. Due to the favorable technological potential of L. brevis, this strain could be used in the production of probiotic products as well as adjunct culture in fermented products.