• Animal Bioscience
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• v.36 no.8
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• pp.1209-1220
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• 2023

Objective: The use of probiotics as an alternative to antibiotics in animal feed has received considerable attention in recent decades. Lactic acid bacteria (LAB) have remarkable functional properties promoting host health and are major microorganisms for probiotic purposes. The aim of this study was to characterize LAB strains of the chicken digestive tract and to determine their functional properties for further use as potential probiotics in poultry. Methods: A total of 2,000 colonies were isolated from the ileum and cecal contents of the chickens based on their phenotypic profiles and followed by a preliminary detection for acid and bile tolerance. The selected 200 LAB isolates with exhibited well-tolerance in acid and bile conditions were then identified by sequencing the 16S rDNA gene, followed by acid and bile tolerance, antimicrobial activity, adhesion to epithelial cells and additional characteristics on the removal of cholesterol. Then, the two probiotic strains (L. ingluviei and L. salivarious) which showed the greatest advantage in vitro testing were selected to assess their efficacy in broiler chickens. Results: It was found that 200 LAB isolates that complied with all measurement criteria belonged to five strains, including L. acidophilus (63 colonies), L. ingluviei (2 colonies), L. reuteri (58 colonies), L. salivarius (72 colonies), and L. saerimneri (5 colonies). We found that the L. ingluviei and L. salivarius can increase the population of LAB and Bifidobacterium spp. while reducing Enterobacteria spp. and Escherichia coli in the cecal content of chickens. Additionally, increased concentrations of valeric acid and short chain fatty acids were also observed. Conclusion: This study indicates that all five Lactobacillus strains isolated from gut contents of chickens are safe and possess probiotic properties, especially L. ingluviei and L. salivarius. Future studies should evaluate the potential for growth improvement in broilers.

• Microbiology and Biotechnology Letters
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• v.44 no.2
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• pp.201-207
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• 2016

The aim of this study was to investigate the potential of lactic acid bacteria (LAB) strains as probiotics. Two strains were isolated from healthy chicken cecum and their acid and bile tolerance, residual organic acids, antibacterial activity against pathogenic bacteria, and immunomodulation activity were measured. Identification of the isolated strains was performed using the API 50CHL system and phylogenetic analysis using 16S rDNA sequencing. The isolates were determined to be Lactobacillus sakei strains. The acid tolerance of strains L2 and L8 was high enough that 75% of the inoculum survived in pH 2 for 2 h. The bile tolerance of both strains was observed at a 1% Oxgall concentration in MRS broth. The production of organic acids (lactic acid and acetic acid) and pH changes during growth were monitored and the maximum concentrations were obtained after 48 h of incubation. Culture supernatants of the two LAB strains showed strong antibacterial activity against pathogenic bacteria. The heat-killed LAB cells also induced high levels of immune cell proliferation compared with the control, and stimulated IL-6 and TNF-α production in mouse macrophages. Therefore, L. sakei strains L2 and L8 can be considered suitable probiotic bacteria.

• Journal of Microbiology and Biotechnology
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• v.32 no.1
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• pp.64-71
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• 2022

The discarding of wastes into the environment is a significant problem for many communities. Still, food waste can be used for lactic acid bacteria (LAB) growth. Here, we evaluated three growth media equivalent to de Mann Rogosa Sharpe (MRS), using apple bagasse, yeast waste, fish flour, forage oats, and cheese whey. Cell-free supernatants of eight LAB strains were tested for antimicrobial activity against nine indicator microorganisms. The supernatants were also evaluated for protein content, reducing sugars, pH, and lactic acid concentration. Cell-free supernatants from fish flour broth (FFB) LAB growth were the most effective. The strain Leuconostoc mesenteroides PIM5 presented the best activity in all media. L. mesenteroides CAL14 completely inhibited L. monocytogenes and strongly inhibited Bacillus cereus (91.1%). The strain L. mesenteroides PIM5 consumed more proteins (77.42%) and reducing sugars (56.08%) in FFB than in MRS broth (51.78% and 30.58%, respectively). Culture media formulated with agroindustrial wastes positively improved the antimicrobial activity of selected LAB, probably due to the production of antimicrobial peptides or bacteriocins.

• Toxicological Research
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• v.29 no.2
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• pp.99-106
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• 2013

Clostridium difficile infection (CDI) has become a significant threat to public health. Although broad-spectrum antibiotic therapy is the primary treatment option for CDI, its use has evident limitations. Probiotics have been proved to be effective in the treatment of CDI and are a promising therapeutic option for CDI. In this study, 4 strains of lactic acid bacteria (LAB), namely, Lactobacillus rhamnosus (LR5), Lactococcuslactis (SL3), Bifidobacterium breve (BR3), and Bifidobacterium lactis (BL3) were evaluated for their anti-C. difficile activity. Co-culture incubation of C. difficile ($10^6$ and $10^{10}$ CFU/ml) with each strain of LAB indicated that SL3 possessed the highest antimicrobial activity over a 24-hr period. The cell-free supernatants of the 4 LAB strains exhibited $MIC_{50}$ values between 0.424 mg/ml (SL3) and 1.318 (BR3) mg/ml. These results may provide a basis for alternative therapies for the treatment of C. difficile-associated gut disorders.

• Journal of Dairy Science and Biotechnology
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• v.37 no.2
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• pp.83-93
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• 2019

Food spoilage by fungi is responsible for considerable food waste and economical losses. Among the food products, fermented dairy products are susceptible to deterioration due to the growth of fungi, which are resistant to low pH and can proliferate at low storage temperatures. For controlling fungal growth in dairy products, potassium sorbate and natamycin are the main preservatives used, and natamycin is approved by most countries for use in cheese surface treatment. However, a strong societal demand for less processed and preservative-free food has emerged. In the dairy products, lactic acid bacteria (LAB) are naturally present or used as cultures and play a key role in the fermentation process. Fermentation is a natural preservation technique that improves food safety, nutritional value, and specific organoleptic features. Production of organic acids is one of the main features of the LAB used for outcompeting organisms that cause spoilage, although other mechanisms such as antifungal peptides obtained from the cleavage of food proteins and competition for nutrients also play a role. More studies for better understanding these mechanisms are required to increase antifungal LAB available in the market.

• Journal of Microbiology and Biotechnology
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• v.26 no.6
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• pp.1035-1045
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• 2016

To evaluate the effects of lactic acid bacteria (LAB) on Peyer's patch cells, mice were treated with a high dose of kanamycin to disturb the gut microbial environment. The overarching goal was to explore the potential of LAB for use as a dietary probiotic that buffers the negative consequences of antibiotic treatment. In vitro, LAB stimulated the production of immunoglobulin A (IgA) from isolated Peyer's patch cells. Inflammation-related genes (TNF-α, IL-1β, and IL-8) were up-regulated in Caco-2 cells stimulated with lipopolysaccharide (LPS), while tight-junction-related genes (ZO-1 and occludin) were down-regulated; the effects of LPS on inflammatory gene and tight-junction gene expression were reversed by treatment with LAB. Mice treated with a high dose of kanamycin showed increased serum IgE levels and decreases in serum IgA and fecal IgA levels; the number of Peyer's patch cells decreased with kanamycin treatment. However, subsequent LAB treatment was effective in reducing the serum IgE level and recovering the serum IgA and fecal IgA levels, as well as the number of Peyer's patch cells. In addition, ZO-1 and occludin mRNA levels were up-regulated in the ileum tissues of mice receiving LAB treatment. Lactic acid bacteria can enhance the intestinal immune system by improving the integrity of the intestinal barrier and increasing the production of IgA in Peyer's patches. Lactic acid bacteria should be considered a potential probiotic candidate for improving intestinal immunity, particularly in mitigating the negative consequences of antibiotic use.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.994-998
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• 2007

Changes in microflora, pH, reducing sugar content, lactic acid content, and ethanol content during Korean rice wine fermentation were investigated. Typical quality characteristics of Korean rice wine fermentation including pH, reducing sugar content, lactic acid content, and ethanol content were evaluated. While a fungus was not detected in our Korean rice wine mash, yeast was found to be present at fairly high quantities (1.44-4.76\;{$\times}\;10^8\;CFU/mL$) throughout the fermentation period. It is assumed that lactic acid bacteria (LAB) had effects on the variations of fragrance and flavor for traditional Korean rice wine. The main LAB during the Korean rice wine fermentation was determined and identified as a Gram-positive, straight rod-shaped cell. Genotypic identification of the isolated strain by amplification of its 16S rRNA sequence revealed that the isolated strain was most closely related to Lactobacillus plantarum (99%) strains without any other comparable Lactobacillus strains. Therefore, we designated the major LAB identified from traditional Korean rice wine fermentation as L. plantarum RW.

• Journal of the Korean Society of Food Culture
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• v.34 no.2
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• pp.142-158
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• 2019

Kimchi is a traditional Korean fermented vegetable probiotic food. The use of high quality ingredients and predominant LAB (lactic acid bacteria)-whether it be ambient bacteria or adding starters, low temperature and facultative anaerobic condition for the fermentation are important factors for preparing kimchi with better taste and functionality. The predominated LAB genera are Leuconostoc, Lactobacillus, and Weissella in kimchi fermentation. The representative species are Leu. mesenteroides, Leu. citrium, Lab. plantarum, Lab. sakei, and Wei. koreensis. Kimchi, especially the optimally fermented kimchi, has various health benefits, including control of colon health, antioxidation, antiaging effects, cancer preventive effect, antiobesity, control of dyslipidemic and metabolic syndrome, etc.; due to the presence of LAB, various nutraceuticals, and metabolites from the ingredients and LAB. The kimchi LAB are good probiotics, exhibiting antimicrobial activity, antioxidant, antimutagenic and anticancer effects, as well as immunomodualatory effect, antiobesity, and cholesterol and lipid lowering effects. Thus, kimchi ingredients, LAB, fermentation methods, and metabolites are important factors that modulate various functionalities. In this review, we introduced recent information showing kimchi and its health benefits in Korean Functional Foods (Park & Ju 2018).

• Korean Journal of Food Science and Technology
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• v.49 no.4
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• pp.377-382
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• 2017

The objective of this study was to isolate and characterize lactic acid bacteria (LAB) exhibiting cholesterol-lowering activity from the Korean traditional fermented food, kimchi. The previously isolated LAB strains were assessed for cholesterol-lowering efficacy in the presence of 0.1% cholesterol. All LAB strains tested in this study were able to assimilate cholesterol at varying levels, ranging from 35.0 to 99.4%. Among them, the Lactobacillus plantarum FMB 31 strain exhibited the highest cholesterol-lowering effect with 99.4% cholesterol removal efficiency. The strain was stable in the presence of acid, bile, and salt stress, and showed high adherence on HT-29 cells, a human colon line. In addition, the LAB strain showed no pathogenic properties such as the production of hemolysin and biogenic amines. Thus, this study suggests that the L. plantarum FMB 31 strain isolated from kimchi can be a potential source of probiotic products with strong cholesterol-lowering effect.

• Journal of Applied Biological Chemistry
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• v.63 no.4
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• pp.375-385
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• 2020

The purpose of this study was to investigate the quality characteristics of kimchi prepared with a single starter culture of biogenic amines (BA)-forming lactic acid bacteria (LAB) or a combined starter cultures composed of BA-forming and BA-degrading LAB. As the fermentation proceeded, the lactic acid bacterial count, titratable acidity, and BA content in kimchi prepared with myeolchi-aekjeot were slightly higher than those of kimchi prepared with saeu-jeot. The amount and type of BA produced by LAB were mostly strain dependent rather than species specific. Among all of the isolated LAB strains, the highest levels of cadaverine, histamine, putrescine and tyramine were produced by Leuconostoc mesenteroides MBK32, Lactobacillus brevis MBK34, Lactobacillus curvatus MBK31 and Enterococcus faecalis SBK31, respectively. BA-forming and BA-degrading starter cultures played an important role in the growth rate and organic acid-producing ability of LAB in kimchi. Interestingly, BA contents in kimchi increased by adding single BA-forming LAB starter were effectively lowered by the mixed cultures with BA-degrading LAB.