Isolation and Characterization of Some Food Grade Lactic Acid Bacteria for their Application as Probiotics

Abstract

Probiotics, which are living, non-pathogenic microorganisms, can enhance a person's health, immunity, and mental function when taken in large quantities together with food. In the present study, seven microbial strains (L1, L2, C1, C2, C3, X, and Y) were isolated from locally collected fresh palm sap and characterized morphologically and biochemically. Among them, two strains were yeast (L1 and C3), two were Bacillus (C2, Y) and three were Cocci (L2, C1, X). All the bacterial isolates were gram-positive and catalase-negative. They showed a broad antimicrobial spectrum against both gram-positive (Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis MB1, Leuconostoc messenteroides Ly) and gramnegative bacteria (Salmonella abony, Escherichia coli). There was little or no change in the growth after three hours of incubation at pH 2, 2.5 and 3. So all the strains were tolerant of gastric acidity. Bacterial isolates were checked for their survivability in the presence of bile salt. Strain L2 showed maximum tolerance to 0.3% bile salt. So, this strain can be further checked in vivo for its usefulness as a probiotic.