Revista de tecnología y procesamiento de alimentos

Abstracto

Characterization and Kinetics of Growth of Bacteriocin like Substance Produced by Lactic Acid Bacteria Isolated from Ewe Milk and Traditional Sour Buttermilk in Iran

Mahdieh Iranmanesh, Hamid Ezzatpanah, Naheed Mojgani and Torshizi MAK

Ethnic people of Iran consume variety of traditional fermented milk products including buttermilk made from ewe's milk. The purpose of this study was to isolate and characterize bacteriocin producing by Lactic acid bacteria from these products, and to exploit their potential as bio preservative. Ten strains of Lactic acid bacteria isolated from ewe's milk, traditional yoghurt and sour buttermilk from different areas in Azarbayjan-e-sharqi, Iran were screened for their ability to produce bacteriocin like inhibitory substances (BLIS). According to results, Lactobacillus pentosus, Lactobacillus paracasei, Lactobacillus brevis, Pediococcus acidilactici were shown to produce proteinaceous substances inhibitory against a number of Gram positive and negative bacteria including Staphylococcus aureus, Listeria monocytogenes and Salmonella enteritidis. The inhibitory activities of two Lactic acid bacteria (Lactobacillus paracasei and Pediococcus acidilactici isolated from ewe milk and buttermilk respectively) were unaffected by the action of pH neutralization and hydrogen peroxide while completely inhibited in the presence of proteolytic enzymes. The kinetic of bacteriocin like inhibitory substances against Staphylococcus aureus indicated a direct relationship between the growth rate and the amount of bacteriocin produced. The inhibitory activity of these lactic acid bacteria started in the early logarithmic phase and continued to the end of exponential phase. During ultrafiltration studies, bacteriocins produced by Pediococcus acidilactici, Lactobacillus paracasei were able to pass through the cellulose membranes with10 and 30 KDa. Titre of bacteriocins produced by Lactobacillus pentosus, Lactobacillus paracasei, Lactobacillus brevis were estimated 1600 AU/mL while the titre for bacteriocin which produced by Pediococcus acidilactici was calculated as 3200 AU/mL.