Growth and antimicrobial activity of proteolytic probiotic Lactobacillus rhamnosus C6 in soymilk and whey

Abstract

Lactobacillus rhamnosus is one of the most common bacteria in the gastro intestinal tract of healthy individuals. Lactobacillus rhamnosus C6 (isolated from cheese) a proteolytic bacteria with proteolytic activity 509.12 µg serine/ml. Lactobacillus rhamnosus C6  also showed the  probiotic attributes as it survived at low pH (pH 1.0) and high bile concentration (up to 2%) having cell surface hydrophobicity for n-hexadecane (28.53 ± 0.37 %).The culture grown in broth also possesed antimicrobial activity against test pathogens (diameter of zone of inhibition ranging 17.76 to 23.77 mm) and showed good growth (9.19 log cfu/ml) in whey and also in soy milk (8.88cfu/ml) after 48 h of incubation. Lactobacillus rhamnosus C6 fermentate of whey and soy milk showed antimicrobial activity against S. Typhi NCTC 6017, S. aureus MTCC 1144, S. dysenteriae NCDC 107, L. monocytogenes ATCC 15303, B. cereus ATCC 13061 and E. coli 0157:H7 ATCC 35150. So, the results of our study revealed that Lactobacillus rhamnosus C6 is a good proteolytic as well as probiotic organism and can grow well in cheese whey as well as soy milk.