Screening, Characterization, and in Vitro Evaluation of Probiotic Properties of Lactobacillus Strains

Abstract

Objective: The aim of the present investigation was to isolate and identify Lactobacillus strains from dairy and cattle dung samples. Potent isolates were selected for screening by antimicrobial activity; selected lactobacilli were further tested for probiotic properties and adhesive attributes.Methods: Lactobacilli were isolated aseptically on specific de man, rogosa and sharpe medium from dairy and cattle dung samples. Isolates were identified by Gram-staining, motility, catalase, endospore, and carbohydrate fermentation tests. Further, the isolates were screened for antimicrobial activity by disk diffusion assay, and potent lactobacilli were observed for probiotic properties: Acid and bile salt tolerance, gelatinase activity, and autolytic activity. For analyzing the adhesive attributes, isolates were observed for autoaggregation, coaggregation and microbial adhesion to solvents assay. Results: About 12Lactobacillus strains among 98 isolates exhibited maximum antimicrobial activity were further selected for identifying their probiotic and adhesive attributes. Among 12 selected isolates, cell-free supernatant (CFS) of buffalo milk BM10 and goat milk GM10 showed excellent antimicrobial activity, 20.34±0.02 mm against Staphylococcus aureus and 18.65±0.11 mm against Escherichia coli. Isolates showed survival at pH 2 and 3 and can tolerate 0.2-0.3% bile salt concentrations. The GM5 showed maximum autoaggregation (67.04±0.61%) and minimum coaggregation (11.51±0.50%) showed by GM3. The BM10 exhibited maximum adherent value 64.84±1.41% for n-hexadecane. Conclusion:The two lactobacilli, BM10 and GM10 identified as Lactobacillus fermentum and Lactobacillus pentosus on the basis of phenotypic and sugar utilization tests. The CFS of both lactobacilli can be used as antimicrobial agent. Both isolates showed significant results of probiotic and adhesive attributes, therefore, can be evaluated for clinical and therapeutic applications.

Selection of Buffalo Milk Lactic Acid Bacteria With Probiotic Potential

“…For example, BMS 1.1 experienced a 37% decrease indicating lower resistance to acid. This result for BMA 3.3 is even higher than the lactic acid bacteria isolated from milk and cattle dung samples by Jain et al [13], which is regarded as a potential probiotic because it can survive at pH 2 (56.93-80.88%) and pH 3 (61.44-81.25%). While the lactobacillus investigated by Singh et al [17] showed a tolerance to acid at pH 2 (46.47-79.74%).…”

“…Overall, BMA 3.3 shows the most promising antibacterial properties against both common pathogens. The antibacterial activity of BMA 3.3 isolates against S. aureus ATCC 25923 and E. coli O157:H7 was lower than that of Lactobacillus fermentum isolated from buffalo milk by Jain et al [13], which had higher antibacterial activity against S. aureus (20.34 ± 0.02 mm). However, the strain does show a significant protective effect against both E. coli and S. aureus.…”

“…Measurements to determine the cell-surface hydrophobicity can be conducted in vitro by measuring the percentage adherence of microbial cells to solvents such as xylene, toluene, or n-hexadecane [13]. Xylene, toluene, and n-hexadecane can be used because they are non-polar and their hydrophobic properties help interact with the hydrophobic microbial surfaces.…”

In vitro evaluation of probiotics and their effect on hatchery production and farming of L. Vannamei

“…These guidelines state that safety and functionality properties like resistance to bile toxicity, gastric acidity, and antibiotic resistance, adhesion to intestinal cell lines, antimicrobial activity, cholesterollowering potential, and immunomodulation potential are extremely important and should be investigated using dependable in vitro screening methods. In the current investigation, isolated lactobacillus from commercial probiotics was assessed for its probiotic qualities using in vitro assay techniques (Neha Jain et al, 2017) [20] . When L. Vannamei tanks' water quality was taken into account, the pH ranged from 8.2 to 8.9 in probiotic-treated ponds whereas it stayed below 8 in controls (Sreenivasulu et al, 2016) [29] .…”

Potential of dadiah kapau from Agam District, West Sumatra, Indonesia as a source of probiotics for health

“…The yield of palm sugar isolate was even higher than that of Lactobacillus rhamnosus isolated from buffalo milk from Karnataka, India, which had a viability of 30% at pH 3 for 3 hours (Shafakatullah and Chandra 2014). Lactic acid bacteria isolated from milk and cow dung samples by Jain et al (2017) can survive at pH 3 (71.05-84.61 %).…”