• Journal of Microbiology and Biotechnology
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• v.31 no.6
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• pp.840-846
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• 2021

To improve the bile salt and acid tolerance of probiotics against gastrointestinal stresses, we investigated the effects of soybean lecithin and whey protein concentrate (WPC) 80 on the bile salt tolerance of Lacticaseibacillus paracasei L9 using a single-factor methodology, which was optimized using response surface methodology (RSM). The survival rate of L. paracasei L9 treated with 0.3% (w/v) bile salt for 2.5 h, and combined with soybean lecithin or WPC 80, was lower than 1%. After optimization, the survival rate of L. paracasei L9 incubated in 0.3% bile salt for 2.5 h reached 52.5% at a ratio of 0.74% soybean lecithin and 2.54% WPC 80. Moreover, this optimized method improved the survival rate of L. paracasei L9 in low pH condition and can be applied to other lactic acid bacteria (LAB) strains. Conclusively, the combination of soybean lecithin and WPC 80 significantly improved the bile salt and acid tolerance of LAB. Our study provides a novel approach for enhancing the gastrointestinal tolerance of LAB by combining food-derived components that have different properties.

• Microbiology and Biotechnology Letters
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• v.23 no.5
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• pp.513-518
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• 1995

To evaluate bile salt-tolerance of lactic acid bacteria (LAB, Lactobacillus acidophilus ATCC 4356, Lactobacillus casei IFO 3533, Streptococcus thermnophilus KCTC 2185, Lactobacillus lactis ATCC 4797, and Lactobacillus bulgaricus ATCC 11842), We investigated the survivals, acid production and $\beta $-galactosidase activity of LAB under anaerobic broth system. Cellular permeability of LAB and their cellular retention of $\beta $-galactosidase were also examined in the same system. Although the growth of LAB was slightly suppressed by 0.3% bile salt, they showed normal growth curve. Streptococcus thermophilus KCTC 2185 was significantly more resistant to bile salt than the others. The $\beta $-galactosidase activity from Streptococcus thermophilus KCTC 2185 and Lactobacillus bulgaricus ATCC 11842 and their cellular retention of $\beta $-galactosidase decreased by 0.3% bile salt. The cellular permeability of LAB in the presence of bile salt increased significantly.

• Journal of Dairy Science and Biotechnology
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• v.37 no.1
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• pp.40-48
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• 2019

Bifidobacteria are a prototype probiotic, which normally inhabit the intestinal tract of humans. In the present study, four species of Bifidobacterium isolated from the feces of infants were characterized. The tolerance for acid or bile salt, autoaggregation, and antibiotic resistance of the bacteria were examined. The four species were resistant to low pH, bile salts, and up to 3% bile acid. Autoaggregation rates were as high as 90%. The bacteria were consistently resistant to gentamicin, kanamycin, streptomycin, ciprofloxacin, and nalidixic acid. Due to their tolerance to environmental factors like acid and bile salts, B. longum MG723, B. breve MG729, B. bifidum MG731, and B. animalis subsp. lactis MG741 are potentially valuable as probiotics and may be useful for industrial application.

• Korean Journal of Poultry Science
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• v.27 no.3
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• pp.227-233
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• 2000

Preset study was carried out to evaluate characteristics of lactic acid producing bacteria(LAB) in hen's cecum as probiotics value. Distribution of LAB in intestinal tracts was investigated using 5∼25 weeks - old hens. So, 12 strains to LAB with different morphology were isolated purely. Acid tolerance of LAB tested at pH 1, 2, 3, and 4, and bile resistant also tested at 0, 0.3% and 0.5% bile salt concentration. Growth pattern of LAB observed to 60h. All strains of cecal LAB couldn't survive at pH 1, and decreased linearly survival colony after incubation at pH 2 although some strains could survive for 2h. Most of LAB maintained constant number at pH 3 and 4. The bacterial action could increase linearly at 0% bile salt concentration in all of tested strains. However, only one strain could multiply at 0.3% bile salt, others were influenced by bile salt. That tendency was similar at 0.5% bile salt. Growth was peaked at 12 to 18 h after innoculation. After peak, the decreasing pattern of colony was different to strains which some strains decreased rapidly or maintained for long time. The LAB of hen's cecum was similar to intolerance acidity, but different to resistant to bile salt and growth pattern by strain. So, we choose three strains which have probiocs value, and identified as Lactobacillus amylovorus LLA7, Lactobacillus crispatus LLA9 and Lactobacillus vaginalis LLA11.

• Journal of Microbiology and Biotechnology
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• v.25 no.12
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• pp.2100-2105
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• 2015

Probiotic bacteria must have not only tolerance against bile salt but also no genes for antibiotic resistance. Leuconostoc citreum is a dominant lactic acid bacterium in various fermented foods, but it is not regarded as a probiotic because it lacks bile salt resistance. Therefore, we aimed to construct a bile salt-resistant L. citreum strain by transforming it with a bile salt hydrolase gene (bsh). We obtained the 1,001 bp bsh gene from the chromosomal DNA of Lactobacillus plantarum and subcloned it into the pCB4170 vector under a constitutive P710 promoter. The resulting vector, pCB4170BSH was transformed into L. citreum CB2567 by electroporation, and bile salt-resistant transformants were selected. Upon incubation with glycodeoxycholic acid sodium salt (GDCA), the L. citreum transformants grew and formed colonies, successfully transcribed the bsh gene, and expressed the BSH enzyme. The recombinant strain grew in up to 0.3% (w/v) GDCA, conditions unsuitable for the host strain. In in vitro digestion conditions of 10 mM bile salt, the transformant was over 67.6% viable, whereas only 0.8% of the host strain survived.

• Korean Journal of Microbiology
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• v.47 no.3
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• pp.231-240
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• 2011

The objective of this study was to evaluate the acid and bile tolerance, bile salt hydrolase (BSH) activity, and cholesterol assimilation ability of lactic acid bacteria isolated from mustard leaf kimchi. MLK11, MLK22, MLK27, MLK41, and MLK67 were relatively acid- and bile-tolerant strains, with more than $10^5$ CFU/ml after incubation in simulated gastric juice and intestinal fluid, while MLK53 was the most sensitive strain to acid and bile. Strains MLK22 and MLK67 deconjugated the highest level of sodium glycocholate with more than 3.5 mM of cholic acid released, while deconjugation was lowest by strains MLK13 and MLK41 which released only 1.35 mM and 1.16 mM, respectively. Specially, strains MLK22 and MLK67 showed higher deconjugation of sodium glycocholate compared to sodium taurocholate and conjugated bile mixture. Although strains MLK22 and MLK67 exhibited maximal BSH activity at the stationary phase, MLK22 had somewhat higher total BSH activity compared to MLK67 towards both sodium glycocholate and sodium taurocholate. Meanwhile, cholesterol removal varied among tested strains (p<0.05) and ranged from 5.22 to 39.16 ${\mu}g$/ml. Especially, MLK67 strain assimilated the highest level of cholesterol in media supplemented with 0.3% oxgall, cholic acid, and taurocholic acid (p<0.05). According to physiological and biological characteristics, pattern of carbohydrate fermentation, and 16S rDNA sequence, strain MLK67 that may be considered as probiotic strain due to acid and bile tolerance and cholesterol-lowering effects was identified as Pediococcus pentosaceus MLK67.

• Preventive Nutrition and Food Science
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• v.11 no.2
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• pp.140-145
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• 2006

Seventy eight bacterial strains were isolated from several jeotgals using MRS and M 17 agar media. The probiotic properties such as tolerance of extreme growth condition, production of antimicrobial compound, production of hydrogen peroxide, and enzymatic activity of bile salt hydrolase were investigated. DHK 4, 10, 21 and 74 strains showed_a strong tolerance property against extreme conditions such as low pH and 0.5% oxgall-supplemented medium. DHK 10 and 47 strains produced hydrogen peroxide on TMB agar plate. DHK 8 and 10 strains produced antimicrobial compounds onto MRS agar against E. facalis. DHK 4, 6, 21, 29, 33, 63 and 87 strains had high activities of bile salt hydrolase. Especially, DHK 10 displayed a strong probiotic candidate; the abilities to produce the antimicrobial compound, hydrogen peroxide, and bile salt hydrolase. All these strains are assumed to be useful probiotic candidates. Among 78, twenty seven strains which have probiotic properties were tentatively identified by 16S rRNA sequencing. Among them, 7 Lactobacillus spp., 6 Leuconosotoc spp., 2 Weisella spp., 1 Pediococcus sp., 1 Staphylococcus sp., 1 Enterococcus sp. and 2 Streptococcus spp. were tentatively identified.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.5
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• pp.726-731
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• 2003

The aim of this research was to identify candidate probiotic lactic bacteria among indigenous dadih lactic isolates. Dadih is an Indonesian traditional fermented milk of West Sumatra which is fermented naturally. Viability of the strain is critical in determining the capacity of lactic bacteria to induce immune stimulation as well as to colonize in the intestinal tract. Therefore, LAB are proposed to exert health promoting or probiotic effects in human, such as inhibition of pathogenic microflora, antimutagenic, and the reduction of cholesterol levels. This manuscript reports in vitro probiotic properties of indigenous dadih lactic bacteria, especially some important colonization factors in GI tract, such as lysozyme, acid and bile tolerance. Bile Salt Hydrolase (BSH) activity, spectrum of bacteriocin, and antimutagenic activity of bacterial cells were also assessed. Twenty dadih lactic isolates were screened further for their tolerance to low pH, at pH 2 and 3 as well as their bile tolerance. There were ten isolates classified as acid and bile acid tolerant, and further screened for lysozyme tolerance, BSH activity. The spectrum of bacteriocin activity of isolates was assayed using cell-free neutralized supernatants by agar spot test against variety of pathogens. Lc. lactis subsp. lactis IS-10285, IS-7386, IS-16183, IS-11857 and IS-29862, L. brevis IS-27560, IS-26958 and IS-23427, Leu.mesen.mesenteroides IS-27526, and L. casei IS-7257 each has good survival rate at low pH values and in the presence of lysozyme, and short lag time in the presence of 0.3 % oxgall. Lc. lactis subsp. lactis IS-11857 and IS-29862 each has high BHS activity, Lc. lactis subsp. lactis IS-10285 and IS-16183 each had a positive spectrum of bacteriocin activity against E. coli 3301 and Lysteria monocytogenes ATCC 19112, while L. brevis IS-26958 has high BHS activity as well as positive spectrum of bacteriocin against E. coli 3301, Lysteria monocytogenes ATCC 19112, and S. aureus IFO 3060. All of the ten dadih lactic strains performed in vitro acid and bile tolerance, indicating a possibility to reach the intestine alive, and display probiotic activities.

• Microbiology and Biotechnology Letters
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• v.48 no.3
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• pp.276-286
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• 2020

Probiotics are live microorganisms that, when administered in adequate amounts, confer health benefits to the host. This study was conducted for the isolation of potential lactic acid bacteria (LAB) with probiotic properties from goat milk and yogurt. Several tests were conducted in vitro using the standard procedures for evaluating the inhibitory spectra of LAB against pathogenic bacteria; tolerance to NaCl, bile salt, and phenol; hemolytic, milk coagulation, and bile salt hydrolase activities; gastrointestinal transit tolerance; adhesion properties; and antibiotic susceptibility. Among 40 LAB strains screened according to culture characteristics, five isolates exhibited antagonistic properties. Three were identified as Pediococcus acidilactici, and two were identified as Enterococcus faecium, exploiting 16S rRNA gene sequencing. All the isolates succeeded in the gastrointestinal transit tolerance assay and successively colonized mucosal epithelial cells. Based on the results of these in vitro assays, both P. acidilactici and E. faecium can be considered as potential probiotic candidates.

• Journal of Biomedical and Translational Research
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• v.19 no.4
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• pp.65-72
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• 2018

The purpose of this study was to investigate probiotic characteristics and immune enhancing effects of Bifidobacterium (B.) longum KBB1-26 and BIF-4, B. breve KBB5-22 isolated from human intestine for probiotic use in humans and animals. We measured acid, bile and heat tolerance, antimicrobial activity against pathogenic bacteria, Escherichia (E.) coli, Salmonella (S.) Enteritidis, Staphylococcus (S.) aureus, and Listeria (L.) monocytogenes. Immune enhancing effects of B. longum and B. breve were investigated by measuring nitric oxide (NO), nuclear factor ($NF-{\kappa}b$), $interleukin-1{\beta}$ ($IL-1{\beta}$), interleukin-6 (IL-6), interleukin-12 (IL-12) and tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$) in RAW 264.7 cells or RAW BLUE cells. B. longum KBB1-26 was survived at pH 2.0. B. longum KBB1-26 and BIF-4, B. breve KBB5-22 also showed tolerance to 0.3% of oxgall bile salt. B. longum KBB1-26 was able to survive at $70^{\circ}C$ and $80^{\circ}C$ for 20 min. KBB1-26 showed the antimicrobial inhibition zone to pathogenic bacteria such as E. coli (12 mm), S. Enteritidis (14 mm), S. aureus (14 mm) and L. monocytogenes (41 mm). The production of NO ($4.5{\pm}0.00{\mu}M/mL$) and $IL-1{\beta}$ ($39.7{\pm}0.55pg/mL$) of KBB1-26 significantly higher than BIF-4 and KBB5-22, respectively. In addition, KBB1-26 and KBB5-22 induce the production of high level of $TNF-{\alpha}$ and IL-6 in macrophages. Collectively, B. longum KBB1-26 have acid, bile, heat tolerance, antimicrobial activity and immune enhancing effects. These results suggest that KBB1-26 can be used as probiotics for humans and animals.