• Journal of Microbiology and Biotechnology
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• v.26 no.9
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• pp.1527-1532
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• 2016

Strain SPF4211, having hyaluronidase (HAase) inhibition activity, was isolated from P. davidiana (Carriere) Franch fruit (PrDF) sugar extract. The phenotypic and biochemical properties based on 16S rDNA sequencing and an API 50 CHB kit suggested that the organism was B. subtilis. To optimize the HAase inhibition activity of PrDF extract by fermentation of strain SPF4211, a central composite design (CCD) was introduced based on three variables: concentration of PrDF extract (X₁: 1-5%), amount of starter culture (X₂: 1-5%), and fermentation time (X₃: 0-7 days). The experimental data were fitted with quadratic regression equations, and the accuracy of the equations was analyzed by ANOVA. The statistical model predicted the highest HAase inhibition activity of 37.936% under the optimal conditions of X₁ = 1%, X₂ = 2.53%, and X₃ = 7 days. The optimized conditions were validated by observation of an actual HAase inhibition activity of 38.367% from extract of PrDF fermented by SPF4211. These results agree well with the predicted model value.

• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.498-508
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• 2019

Bacillus species were isolated from iru, a traditional fermented condiment in Nigeria. Polyphasic approach was used to evaluate the phylogenetic relationship and strain sub-type of the isolated species. Additionally, the phylogenetic profiles of the species isolated from iru were compared with those of bacilli isolated from different continents. The phylogenetic diversity analysis was performed using the combination of 16S rRNA gene sequencing, ITS-PCR, ITS-PCR-RFLP, and M13 RAPD-PCR. The analysis revealed that Bacillus subtilis U170B and B. subtilis U146A isolated from iru were the closest relatives of strains belonging to the phylogeny of B. subtilis sensu stricto and were related to other bacilli isolated from different continents that had functional benefits. The two isolated species exhibited resistance to acidic pH (pH 2.0). The survival rates of B. subtilis U170B, B. subtilis U146A, and B. clausii UBBC-07 (commercial probiotic strain) cultured at pH 2.0 for 3 h were 33.45, 12.44, and 9.53%, respectively. The strains were highly tolerant to bile salts [0.3% (w/v)]. B. subtilis U170B exhibited the highest cell viability (43.45%) when cultured for 3 h in the presence of bile salts, followed by B. subtilis U146A (25%) and B. clausii UBBC-07 (18.94%). B. subtilis U170B and B. subtilis U146A did not exhibit haemolytic activity and were susceptible to different antibiotics. Additionally, these two strains exhibited weak antagonistic activity against B. cereus. The diverse wild strains of B. subtilis can be used as a safe multifunctional starter culture for the industrial production of condiments with health benefits.

• Journal of Microbiology and Biotechnology
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• v.25 no.12
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• pp.2090-2099
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• 2015

Recently, the cardiovascular disease has been widely problematic in humans probably due to fibrin formation via the unbalanced Western style diet. Although direct (human plasmin) and indirect methods (plasminogen activators) have been available, bacterial enzyme methods have been studied because of their cheap and mass production. To detect a novel bacterial fibrinolytic enzyme, 111 bacterial strains with fibrinolytic activity were selected from kimchi. Among them, 14 strains were selected because of their stronger activity than 0.02 U of plasmin. Their 16S rRNA sequence analysis revealed that they belong to Bacillus, Leuconostoc, Propionibacterium, Weissella, Staphylococcus, and Bifidobacterium. The strain B. subtilis ZA400, with the highest fibrinolytic activity, was selected and the gene encoding fibrinolytic enzyme (bsfA) was cloned and expressed in the E. coli overexpression system. The purified enzyme was analyzed with SDS-PAGE, western blot, and MALDI-TOF analyses, showing to be 28.4 kDa. Subsequently, the BsfA was characterized to be stable under various stress conditions such as temperature (4-40oC), metal ions (Mn²⁺, Ca²⁺, K²⁺, and Mg²⁺), and inhibitors (EDTA and SDS), suggesting that BsfA could be a good candidate for development of a novel fibrinolytic enzyme for thrombosis treatment and may even be useful as a new bacterial starter for manufacturing functional fermented foods.

• Journal of Microbiology and Biotechnology
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• v.12 no.1
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• pp.8-13
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• 2002

The isoflavone glycosides are hydrolyzed by ${\beta}$-glucosidase from gut microbes to the bioactive aglycones. However, the specific bacteria from the human intestinal tract that are involved in the metabolism of these compounds are not known. This study was undertaken to develop a fermented soymilk which converts isoflavones to the more bioactive aglycones form using a Bifidobacterium strain. The ${\beta}$-glucosidase activity of 15 Bifidobacterium strains were measured during cell growth. Among them, Bifidobacterium sp. Int-57 was selected for this study, because it has the highest ${\beta}$-glucosidase activity. Growth, acid development, ${\beta}$-glucosidase activity, and the hydrolysis of daidzin and genistin were investigated in four soymilks inoculated with Bifidobacterium sp. Int-57. After 12 h of fermentation, the counts of viable Bifidobacterium sp. Int-57 in all the soymilks reached a level of more than $10^8$ cfu/ml, which was then maintained. The pH of soymilks started to decrease rapidly after 6 h of fermentation and leveled off after 18 h. The titratable acidity of BL# 1 soymilk, BL#2 soymilk, and JP#l soymilk increased from 0.18 to 1.21, 1.15, and $1.08\%$ over the fermentation period, respectively. After 24 h of fermentation, the $\beta$-glucosidase activity in BL#1 soymilk, BL#2 soymilk, JP#l soymilk, and JP#2 soymilk increased to 59.528, 40.643, 70.844, and 56.962 mU/ml, respectively. The isoflavone glycosides, daidzin and genistin, in soymilks were hydrolyzed completely in the relatively short fermentation time of 18 h. These results show that Bifidobacterium sp. Int-57 can be used as a potential starter culture for developing fermented soymilk which has completely hydrolyzed isoflavone glycosides.

• Journal of Microbiology and Biotechnology
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• v.28 no.7
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• pp.1112-1121
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• 2018

Jeotgal is a Korean traditional fermented seafood with a high concentration of salt. In this study, we isolated lactic acid bacteria (LAB) from galchi (Trichiurus lepturus, hairtail) and myeolchi (Engraulis japonicas, anchovy) jeotgal on MRS agar and MRS agar containing 5% NaCl (MRS agar+5% NaCl), and identified them by using 16S rRNA gene sequencing and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) as culture-dependent methods. We also performed polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) as a culture-independent method to identify bacterial communities. Five samples of galchi-jeotgal and seven samples of myeolchi-jeotgal were collected from different regions in Korea. A total of 327 and 395 colonies were isolated from the galchi- and myeolchi-jeotgal samples, respectively. 16S rRNA gene sequencing and MALDI-TOF MS revealed that the genus Pediococcus was predominant on MRS agar, and Tetragenococcus halophilus on MRS agar+5% NaCl. PCR-DGGE revealed that T. halophilus, Tetragenococcus muriaticus, and Lactobacillus sakei were predominant in both types of jeotgal. T. halophilus was detected in all samples. Even though the same species were identified by both culture-dependent and -independent methods, many species identified by the culture-dependent methods were not in the bacterial list identified by the culture-independent methods. The distribution of bacteria in galchi-jeotgal was more diverse than in myeolchi-jeotgal. The diverse LAB in galchi- and myeolchi-jeotgals can be further studied as candidates for starter cultures to produce fermented foods.

• Journal of the Korean Society of Food Culture
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• v.16 no.4
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• pp.371-377
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• 2001

Li was a sweet beverage containing $2{\sim}3$ percents ethyl alcohol made from malt by spontaneous fermentation from ancient custom to fifteenth century. Li was changed to the rice wine being a sweet beverage of low alcohol content using nuruk as starter and the sikhae which is non-alcoholic fermented beverage. Li was made for drinking and ceremony in Korea, China and Japan. It disappeared from the beverage items along with its method of manufacture from malt, but in Korean had made Li using nuruk until recent. We made Li according to Book of Imwon-Keongjae Ji (The book of country economy) methods for reappearance of Li. Fermentation characteristics for the production of Li with Saccharomyces cerevisiae, Saccharomyces bayanus and Saccharomyces sake were investigated. Among the yeast strains tested, Li fermented with S. sake showed higher alcohol production. Total sugar decreased considerably during the whole period of fermentation(30 hours), while ethyl alcohol content increased at $2.98{\sim}3.52%$. As the fermentation progressed, the pH decreased until the 30 hours of fermentation, while total acid increased during the same period. In fermentation of 36 hours, Li consisted of about $2.98{\sim}3.52%$ of alcohol content, $5.3{\sim}6.0%$ of total sugar, $1.45{\sim}2.21mg%$ of reducing sugar and total acidity were reached up to $24.4{\sim}29.5mg%$ for Li manufactured with S. cerevisiea sake, S. bayanus and S. sake.

• Journal of Microbiology and Biotechnology
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• v.30 no.11
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• pp.1697-1705
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• 2020

Meju, a type of fermented soybean paste, is used as a starter in the preparation of various Korean traditional soybean-based foods. In this study, we performed Illumina-MiSeq paired-end sequencing for microbial communities and mass spectrometry analysis for metabolite profiling to investigate the differences between 11 traditional meju products from different regions across Korea. Even though the bacterial and fungal communities showed remarkable variety, major genera including Bacillus, Enterococcus, Variovorax, Pediococcus, Weissella, and Aspergillus were detected in every sample of meju. The metabolite profile patterns of the 11 samples were clustered into two main groups: group I (M1-5) and group II (M6-11). The metabolite analysis indicated a relatively higher amino acid content in group I, while group II exhibited higher isoflavone, soyasaponin, and lysophospholipid contents. The bioactivity analysis proved that the ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) radical-scavenging activity was higher in group II and the FRAP (ferric reducing antioxidant power) activity was higher in group I. The correlation analysis revealed that the ABTS activity was isoflavonoid, lipid, and soyasaponin related, whereas the FRAP activity was amino acid and flavonoid related. These results suggest that the antioxidant activities of meju are critically influenced by the microbiome and metabolite dynamics.

• Food Science of Animal Resources
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• v.38 no.6
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• pp.1144-1154
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• 2018

Both the calcium and collagen in bone powder are hard to be absorbed by the body. Although enzymatic hydrolysis by protease increased the bio-availability of bone powder, it was a meaningful try to further increase $Ca^{2+}$ release, oligopeptide formation and antioxidant activity of the sheep bone hydrolysate (SBH) by lactic acid bacteria (LAB) fermentation. Lactobacillus helveticus was selected as the starter for its highest protease-producing ability among 5 tested LAB strains. The content of liberated $Ca^{2+}$ was measured as the responsive value in the response surface methodology (RSM) for optimizing the fermenting parameters. When SBH (adjusted to pH 6.1) supplemented with 1.0% glucose was inoculated 3.0% L. helveticus and incubated for 29.4 h at $36^{\circ}C$, $Ca^{2+}$ content in the fermented SBH significantly increased (p<0.01), and so did the degree of hydrolysis and the obtaining rate of oligopeptide. The viable counts of L. helveticus reached to $1.1{\times}10^{10}CFU/mL$. Results of Pearson correlation analysis demonstrated that LAB viable counts, $Ca^{2+}$ levels, obtaining rates of oligopeptide and the yield of polypeptide were positively correlated with each other (p<0.01). The abilities of SBH to scavenge the free radicals of DPPH, OH and ABTS were also markedly enhanced after fermentation. In conclusion, L. helveticus fermentation can further boost the release of free $Ca^{2+}$ and oligopeptide, enhance the antioxidant ability of SBH. The L. helveticus fermented SBH can be developed as a novel functional dietary supplement product.

• Journal of Microbiology and Biotechnology
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• v.32 no.9
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• pp.1146-1153
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• 2022

Many probiotic species have been used as a fermentation starter for manufacturing functional food materials. We have isolated Bifidobacterium animalis subsp. lactis LDTM 8102 from the feces of infants as a novel strain for fermentation. While Glycine max has been known to display various bioactivities including anti-oxidant, anti-skin aging, and anti-cancer effects, the immune-modulatory effect of Glycine max has not been reported. In the current study, we have discovered that the extract of Glycine max fermented with B. animalis subsp. lactis LDTM 8102 (GFB 8102), could exert immuno-modulatory properties. GFB 8102 treatment increased the production of immune-stimulatory cytokines in RAW264.7 macrophages without any noticeable cytotoxicity. Analysis of the molecular mechanism revealed that GFB 8102 could upregulate MAPK2K and MAPK signaling pathways including ERK, p38, and JNK. GFB 8102 also increased the proliferation rate of splenocytes isolated from mice. In an animal study, administration of GFB 8102 partially recovered cyclophosphamide-mediated reduction in thymus and spleen weight. Moreover, splenocytes from the GFB 8102-treated group exhibited increased TNF-α, IL-6, and IL-1β production. Based on these findings, GFB 8102 could be a promising functional food material for enhancing immune function.

• The Korean Journal of Food And Nutrition
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• v.36 no.5
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• pp.360-367
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• 2023

The major active components of Astragalus membranaceus (AM) are isoflavones, which exist in the form of various glycosides. Nuruk is a traditional fermentation starter in Korea, and is suitable for the biotransformation of isoflavone glycosides because it contains various microorganisms and enzymes. This study was performed to determine changes in the isoflavones and antioxidant properties of AM fermented (AF) with nuruk over 24 hours. AF was sampled after 0, 2, 4, 6, 12, 18, and 24 h of fermentation, and calycosin 7-glucoside, ononin, calycosin, and formononetin content, and the antioxidant properties of AF were analyzed. The total phenolic content increased with fermentation time, and the ABTS radical scavenging activity increased until 6 h of fermentation and then decreased. During fermentation, the isoflavone glycosides decreased significantly as fermentation time increased. The contents of calycosin and formononetin, which are aglycons of calycosin-7-glucoside and ononin, increased from 100.54 ㎍/g to 276.84 ㎍/g and from 56.29 ㎍/g to 123.04 ㎍/g, respectively, at 18 h of fermentation. Significant correlations were observed between fermentation time, isoflavone content, and antioxidant properties. The results of this study showed that fermentation with nuruk is suitable for the biotransformation of isoflavones in AM.