Abstract
The present study was undertaken to explore the probiotic potential of Lactobacillus isolated from traditional homemade curd. A total of 32 lactic acid bacterial isolates were screened from homemade curd collected from various regions of chittoor district, Andhra Pradesh, India. Most of the bacterial isolates were found to be gram positive, catalase negative and were preliminarily evaluated for their probiotic potential like acid tolerance, bile tolerance, thermo tolerance, osmo tolerance and antibiotic susceptibility. Among all the 32 isolates, 9 isolates viz. L1, L2, L3, L4, L5, L6, L7, L8, and L9 were found to be having promising probiotic activity were further screened for antagonism against enteropathogens. One of the isolate (Lactobacillus spp L2) with significant probiotic properties, antagonistic activity was characterized by 16S rRNA sequence analysis and was identified as Lactobacillus fermentum. The bacteriocin produced by Lactobacillus fermentum was purified by a process of ammonium sulfate precipitation and chromatography techniques. The study revealed the possibility of using bacteriocin as a food preservative and the Lactobacillus fermentum strain as probiotic.
Highlights
Bacteriocins from Lactic Acid Bacteria (LAB) isolated from traditional foods of India have proven its applicability in biopreservation (Jamuna and Jeevaratnam, 2005)
The inhibitory activity of the selected Lactobacillus isolates was determined using agar well diffusion assay against the enteropathogens Escherichia coli, Enterococcus faecalis, Pseudomonas fluorescence, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhimurium and Proteus mirabilis (Subramanyam et al, 2014)
We have carried out the identification and evaluation of probiotic potential of the Lactobacillus strains isolated from home made curd, characterization of bacteriocinogenic Lactobacillus strain and purification of the antimicrobial compound produced by a naturally fermented curd isolate of lactic acid bacteria, Lactobacillus fermentum
Summary
Bacteriocins from Lactic Acid Bacteria (LAB) isolated from traditional foods of India have proven its applicability in biopreservation (Jamuna and Jeevaratnam, 2005). The DNA– DNA hybridization technique has improved knowledge on taxonomic relationships between Lactobacillus species, but this technique is still time-consuming and labours- intensive (Song et al, 1999) Various methods such as DNA sequencing, fatty acid analysis and RFLP have been established and applied to the identification of probiotics (Yeung, 2002). Sequencing analysis of the 16 S r RNA genes has been used to determine the diversity and dynamics of LAB in food (Chen and Hoover, 2003; Jung-Min, 2010) Bacteriocins produced by this LAB are natural peptides that exert bactericidal activity against pathogenic bacteria and this fact creates the possibility of improving their characteristics to enhance their activity and spectra of action (Saavedra et al, 2004). The purification of bacteriocin from identified Lactobacillus fermentum may exert beneficial effects for mankind
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