• Korean Journal of Microbiology
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• v.37 no.2
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• pp.151-157
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• 2001

This study was conducted to select lactic acid bacteria which possess potential inhibitory effect on Helicobacter pylori, and to make feasibility test of fermented milk products using them. In order to select lactic acid bacteria specifically inhibiting the growth of H. pylori, antibacterial activity using paper disk method, adherence ability to Caco-2 cell inhibitory effect on urease activity of H. pylori, and milk fermentation feasibility were measured. Among 45 strains of lactic acid bacteria tested, 28 strains showed clear zone and Lactobacillus gasseri MK-03 showed the largest clear zone. Caco-2 cell adherence by lactic acid bacteria and inhibitory effect of them on H. pylori adherence were also evaluated. Of 28 strains tested, 18 strains appeared to be effective on adherence to Caco-2 cell, and especially Bifidobacterium longum MK-26 was found to be superior to others. When Bif. longum MK-26 and H. pylori were reacted with Caco-2 cell 2hrs before, adherence percentage of H. pylori decreased from 0.105% to 0.004%. To investigate inhibitory effect of lactic acid bacteria-derived supernatant on urease activity of H. pylori, pH-adjusted fermented supernatant(pH-4.4) was assessed by co-cultivation method. There of Lb. acidophilus MK-07-derived supernatant showed the most inhibitory effect on urease activity of H. pylori. Considering milk fermentation ability of selected 3 strains, they were comparably feasible to fermented milk products. Consequently, Lb. gasseri MK-03, Lb. acidophilus MK-07, and Bif. longum MK-26 were selected to specifically inhibit the growth of H. pylori, by antibacterial activity, inhibition of urease activity, and inhibition of Caco-2 cell adherence, respectively.

• Journal of Dairy Science and Biotechnology
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• v.14 no.1
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• pp.97-118
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• 1996

All over the world there is an increasing consumer awareness of the potential influence of various foodstuffs on our health. Today dairy products are expected to be more just food. They have to taste well, appeal and give pleasure, provide of well-being, provide specific health benefits and prevent disease. This paper reviews the different types of fermented milks and their microflora and includes recent work on yogurt, soft cheese and buttermilks, kefir and koumiss. There is considerable interest in the new health promoting products which are now available. Meanwhile during the last decade a new generation of fermented milk products containing selected intestinal bacteria has been introduced to the markets. These are discussed in the light of some recent findings on the ability to lower the blood cholesterol concentration and stimulate the immune response and also describes some fermented milk products available, selection criteria for commercial starter cultures.

• Journal of Microbiology and Biotechnology
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• v.27 no.7
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• pp.1266-1271
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• 2017

Lactobacillus fermentum strain JDFM216, isolated from a Korean infant feces sample, possesses the ability to enhance the longevity and immune response of a Caenorhabditis elegans host. To explore the characteristics of strain JDFM216 at the genetic level, we performed whole-genome sequencing using the PacBio system. The circular draft genome has a total length of 2,076,427 bp and a total of 2,682 encoding sequences were identified. Five phylogenetically featured genes possibly related to the longevity and immune response of the host were identified in L. fermentum strain JDFM216. These genes encode UDP-N-acetylglucosamine 1-carboxyvinyltransferase (E.C. 2.5.1.7), ErfK/YbiS/YcfS/YnhG family protein, site-specific recombinase XerD, homocysteine S-methyltransferase (E.C. 2.1.1.10), and aspartate-ammonia ligase (E.C. 6.3.1.1), which are involved in peptidoglycan synthesis and amino acid metabolism in the gut environment. Our findings on the genetic background of L. fermentum strain JDFM216 and its potential candidate genes for host longevity and immune response provide new insight for the application of this strain in the food industry as newly isolated functional probiotic.

• Korean Journal of Food Science and Technology
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• v.16 no.3
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• pp.285-290
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• 1984

Growth characteristics of six lactic acid bacteria in whey-soy milk mixtures were investigated to obtain basic informations for processing cheese-like product by coprecipitation of whey and soy proteins. Streptococcus cremoris and Lactobacillus acidophilus produced more aicd than other lactic acid bacteria both in whey-soy milk mixture and in soy milk. Lactic acid fermentation was accelerated in whey-soy milk mixture than in soy milk with all the lactic aicd bacteria, and specially with S. lactis and S. cremoris in great extent. The number of viable cell of 1:1 mixed culture of S. lactis and S. cremoris in whey soy milk mixture was about 10 times than in soymilk. It was mainly the effect of lactose in the whey that increased the acid production by lactic aicd bacteria in whey-soy milk mixture although the degree of acceleration depended on the ability of microorganism to use carbohydrates. The optimum amount of lactose added to soy milk to accelerate the acid production was 0.8g/100ml soy milk.

• Quantitative Bio-Science
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• v.37 no.2
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• pp.125-132
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• 2018

In this study, noble strains of lactic acid bacteria were isolated and identified by genetic analysis of 16s rRNA. Also, pH-dependent growth curve, cholesterol assimilation ability and sugar production efficiency were measured. Lactic acid bacteria were identified to inhabit in the milks from various animals. Results of sequence analysis showed that there were differences in 16S rRNA sequence among strains and part of gene deletion was also recognized. Growth rates were varied, too, depending on the pH of the medium. Lactobacillus rhamnosus LOCK908 isolated from cow milk showed the highest growth rate and high cholesterol assimilation ability. Results of sugar fermentation tests were relatively consistent with the sequencing results. So, we propose newly isolated Lactobacillus rhamnosus LOCK908 as useful candidate for a starter of fermented beverage and probiotics. Results of this study will contribute to the isolation and identification of noble Lactic acid bacteria and to the public health.

• Food Science of Animal Resources
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• v.30 no.3
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• pp.443-448
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• 2010

Casein phosphopeptide (CPP) enhances calcium absorption in humans. Lactic acid bacteria (LAB) are capable of synthesis of cell-surface proteinase, which can hydrolyze milk protein and release several types of peptides in the medium. This study was conducted to characterize proteinase of LAB and to evaluate the CPP production from bovine milk. The content of CPP of milk produced by cell-free extract of LAB was determined based on the quantity of decomposed peptide from casein using the O-phthaldialdehyde (OPA) method. The proteolytic activity of LAB was assayed using fluorescein isothiocyanate (FITC)-labeled casein. Casein appeared to be a better substrate than whey proteins for extracellular proteinases of LAB. During fermentation, milk proteins were hydrolyzed by extracellular proteinase of LAB, resulting in an increase in the amount of free $NH_3$ groups. Overall, the results presented here indicate that CPP produced by LAB may be a promising material for novel applications in the dairy industry.

• Animal Bioscience
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• v.37 no.2_spc
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• pp.370-384
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• 2024

Rumen microbiota play a central role in the digestive process of ruminants. Their remarkable ability to break down complex plant fibers and proteins, converting them into essential organic compounds that provide animals with energy and nutrition. Research on rumen microbiota not only contributes to improving animal production performance and enhancing feed utilization efficiency but also holds the potential to reduce methane emissions and environmental impact. Nevertheless, studies on rumen microbiota face numerous challenges, including complexity, difficulties in cultivation, and obstacles in functional analysis. This review provides an overview of microbial species involved in the degradation of macromolecules, the fermentation processes, and methane production in the rumen, all based on cultivation methods. Additionally, the review introduces the applications, advantages, and limitations of emerging omics technologies such as metagenomics, meta-transcriptomics, metaproteomics, and metabolomics, in investigating the functionality of rumen microbiota. Finally, the article offers a forward-looking perspective on the new horizons and technologies in the field of rumen microbiota functional research. These emerging technologies, with continuous refinement and mutual complementation, have deepened our understanding of rumen microbiota functionality, thereby enabling effective manipulation of the rumen microbial community.

• Journal of Food Hygiene and Safety
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• v.36 no.5
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• pp.440-446
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• 2021

GABA (γ-aminobutyric acid) has various beneficial effects on human health such as anti-hypertension, diuretic, tranquilizer, sleep induction and anti-stress functions. In this study, the properties and the antioxidizing effects of a fermented solution was investigated by applying GABA producing lactic acid bacteria (LAB) from kimchi to corn silk extract. Lactobacillus plantarum LAB459 was identified by physiological properties, carbohydrate fermentation pattern and 16s rRNA sequence analysis. Also, the GABA production ability of the separated L. plantarum LAB459 was confirmed through TLC and HPLC analysis. Moreover, from the fermentation of corn silk extract with skim milk, it was revealed that approximately 1 ㎍/mg of GABA produced by lyophilized ferments was yielded. Lastly, the flavonoid content and DPPH radical scavenging activity were found to be high in the lyophilized ferments than in the aqueous extracts. Therefore, L. plantarum LAB459 is considered to be used as a starter culture for various fermented foods or in food and medicinal materials.

• Food Science of Animal Resources
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• v.29 no.5
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• pp.619-626
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• 2009

As a trial for the development of a new starter culture for yogurt products, more than two hundred lactic acid bacteria strains were isolated from raw milk and healthy human feces. The strains that showed excellent growth and acid production ability in the 10% skim milk media were selected and identified as Lactobacillus casei through the API carbohydrate fermentation pattern and 16S rDNA sequence analysis. L. casei CU2604 was further investigated for its physiological characteristics as a starter culture compared with a commercial strain. The CU2604 strain showed good acid production and growth characteristics in milk, which were comparable to those of the L. casei Shirota strain. Despite the fact that both these strains displayed the same sugar fermenting pattern and PFGE band pattern, and had similar growth characteristic in milk, L. casei CU2604 exhibited different fatty acid composition in the cell wall, showed more tolerance to bile and to pH, and presented better growth inhibition activity against pathogenic bacteria. Based on these results, the L. casei CU2604 strain holds great promise for use as a novel and efficient starter culture in the production of yogurt. Additional studies on the probiotic characteristics of this strain are currently being conducted.

• The Korean Journal of Food And Nutrition
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• v.26 no.2
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• pp.273-279
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• 2013

The microorganisms producing high protease activity and acid producing ability were isolated from Chunggukjang and kimchi, which were identified as Bacillus subtilis and Lactobacillus planetarum by morphological, biochemical and nutrient requirement. The attempt was made to produce soybean milk yoghurt by using the isolated microorganisms. The mixed culture of Bacillus subtilis and Lactobacillus plantarum exhibited the lowest pH value of 4.23 and highest titratable acidity of 0.88% compared to those of single cultures at $37^{\circ}C$ for 32 hrs, and their total viable count was $4.09{\times}10^8$ $cfu/m{\ell}$. The ${\alpha}$-amylase activity was the highest in culture of Bacillus subtilis after incubation for 24 hrs, while protease activity was most produced in mixed culture of Bacillus subtilis and Lactobacillus plantarum. The amounts of reducing sugars were steadily decreased as soy milk fermentation progressed.