Characterization of Indigenous Lactobacillus Strains for Probiotic Properties

Abstract

Background:Probiotics are defined as adequate amount of live microorganisms able to confer health benefits on the host. Currently, most commercially available probiotic products in the market belong to genera Lactobacillus. Traditional dairy products are usually rich source of Lactobacillus strains with significant health benefits. In order to evaluate the probiotic potential of these bacteria, it is essential to assess their health benefits, efficacy, and safety.Objectives:The probiotic efficacy of two Lactobacillus strains namely Lactobacillus pentosus LP05 and L. brevis LB32 was evaluated. They were previously isolated from ewes’ milk in a rural area in East Azerbaijan, Iran.Materials and Methods:The selected isolates were tested for certain phenotypic characters and identified to genus and species level by 16S rRNA gene sequencing and species specific primers. Further analysis included acid and bile resistance, antagonistic activity, cholesterol removing ability, survival in simulated gastric and upper intestine contents, aggregation and coaggregation properties. Finally, the adhering ability of the selected Lactobacillus strains to epithelial cells was tested using Caco-2 cell lines.Results:The selected isolates tolerated bile salt concentrations ranging from 0.5% to 3%, however their coefficient of inhibition were varied. Both isolates hydrolyzed bile and grew at pH values of 3, 4, and 5, while isolate LP05 was not able to hydrolyze arginine. Based on 16s rRNA gene sequencing and species-specific primers, the isolates were identified as L. brevis LB32 and L. pentosus LP05. In contrast to simulated gastric conditions, the growth rate of the isolates in alkaline conditions of upper intestine increased significantly with the passage of time reaching its maximum in 24 hours. These 2 isolates inhibited the growth of Listeria monocytogenes, Salmonella enteritidis, Shigella dysenteriae, Staphylococcus aureus, and Streptococcus pneumonia. Furthermore, L. brevis LB32 was able to reduce approximately 86% of cholesterol compared to L. pentosus LP05, which showed only 69% of reduction. Higher aggregation and coaggregation percentage and adherence to Caco-2 cell line was observed in L. pentosus LP05 compared to L. brevis LB32.Conclusions:This research study proved the presence of viable probiotic LAB microflora in the ewe milk with enhanced health benefits. The 2 selected Lactobacillus strains could be exploited in dairy or pharmaceutical industry in future.

Comparative analysis of spray‐drying microencapsulation of Bifidobacterium adolescentis and Lactobacillus acidophilus cultivated in different growth media

“…Many previous studies have confirmed that probiotics have an ability to adhere to Caco-2 cells in the intestine (Dimitrov, Gotova, & Chorbadjiyska, 2014;Jose, Bunt, McDowell, Chiu, & Hussain, 2017;Mojgani, Hussaini, & Vaseji, 2015). In addition, the medium, strain, and carrier are important and determining factors for adsorption by intestinal cells.…”

Identification and Characterization of Bile Salt Hydrolyzing Lactobacillus Isolates

“…LAB is non-pathogenic, technologically suitable for industrial processes, acid & tolerant and produce antimicrobial substances (Mojgani et al, 2015).…”

Probiotic potential and function of a Lactobacillus strain L1 isolated from Silage

“…It has been found that the presence of immunomodulatory properties and the pattern of immunomodulation depend on the bacterial species involved (Kirjavainen, Ei-Nezami, Salminen, Ahokas, & Wright, 1999) and the bacterial dose (Gill & Rutherfurd, 2001). LAB are non-pathogenic, technologically suitable for industrial processes, acid tolerance, bile tolerance, and produce antimicrobial substances (Mojgani, Fatimah, & Vaseji, 2015). They are classified as generally recognized as safe microorganisms because of their long and safe use as starter cultures in fermented products.…”