• Journal of Microbiology and Biotechnology
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• v.20 no.4
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• pp.763-766
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• 2010

An efficient and simple fermentation process was developed for the production of ${\gamma}$-aminobutyric acid (GABA) by Lactobacillus sakei B2-16. When the L. sakei B2-16 was cultivated in the rice bran extracts medium containing 4% sucrose, 1% yeast extract, and 12% monosodium glutamate, the maximum GABA concentration reached 660.0 mM with 100% conversion yield, showing the 2.4- fold higher GABA concentration compared with the modified MRS medium without the rice bran extracts. The GABA production was scaled-up from a laboratory scale (5 l) to a pilot (300 l) and a plant (5,000 l) scale to investigate the application possibility of GABA production to industrial fields. The production yields at the pilot and plant scales were similar to the laboratory scale using rice bran extracts medium, which could be effective for the low-cost production of GABA.

• Journal of Microbiology and Biotechnology
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• v.26 no.7
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• pp.1182-1189
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• 2016

Lactobacillus brevis ATCC 14869 exhibited a carbon catabolite derepressed phenotype that has ability to consume fermentable sugars simultaneously with glucose. To evaluate this unusual phenotype under harsh conditions during fermentation, the effects of lactic acid and hydrogen ion concentrations on L. brevis ATCC 14869 were examined. Kinetic equations describing the relationship between specific cell growth rate and lactic acid or hydrogen ion concentration were deduced empirically. The change of substrate utilization and product formation according to lactic acid and hydrogen ion concentration in the media were quantitatively described. Although the simultaneous utilization has been observed regardless of hydrogen ion or lactic acid concentration, the preference of substrates and the formation of two-carbon products were changed significantly. In particular, acetic acid present in the medium as sodium acetate was consumed by L. brevis ATCC 14869 under extreme pH of both acid and alkaline conditions.

• Journal of Microbiology and Biotechnology
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• v.25 no.1
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• pp.81-88
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• 2015

This study describes a novel strategy to regulate the metabolic flux for lactic acid production in Lactobacillus casei. The ldhL gene encoding _L-lactate dehydrogenase (L-LDH) was overexpressed in L. casei, and a two-stage oxygen supply strategy (TOS) that maintained a medium oxygen supply level during the early fermentation phase, and a low oxygen supply level in the later phase was carried out. As a consequence, a maximum L-LDH activity of 95.6 U/ml was obtained in the recombinant strain, which was over 4-fold higher than that of the initial strain. Under the TOS for L. casei (pMG-ldhL), the maximum lactic acid concentration of 159.6 g/l was obtained in 36 h, corresponding to a 62.8% increase. The results presented here provide a novel way to regulate the metabolic flux of L. casei for lactic acid production in different fermentation stages, which is available to enhance organic acid production in other strains.

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.3
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• pp.195-200
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• 2015

An investigation was carried out to evaluate the potential role of Lactobacillus Plantarum KCC-10 and KCC-19 on the quality and fermentation characterization of Italian ryegrass (IRG) silages. The physiochemical properties of IRG silage such as crude protein content, neutral detergent fiber, acid detergent fiber, total digestible nutrient and in vitro dry matter digestibility were not affected by KCC-10 and KCC-19. The pH of IRG silage in KCC-10 and KCC-19 treatments decreased compared to the control (p<0.05), while the lactic acid content in KCC-10 and KCC-19 treatments increased compared to the control (p<0.05). In addition, the number of lactic acid bacteria (LAB) in the KCC-10 treatment increased compared to the control (p<0.05). The number of lactic acid bacteria in KCC-19 increased, but there was no significant difference in all treatments. Therefore, we recommend L. plantarum KCC-10 and KCC-19 as potential additive candidates in IRG silage with lots of advantages.

• Journal of Microbiology and Biotechnology
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• v.25 no.8
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• pp.1315-1320
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• 2015

To enhance the γ-aminobutyric acid (GABA) content, the optimized fermentation of soybean with added sea tangle extract was evaluated at 30℃ and pH 5.0. The medium was first inoculated with Aspergillus oryzae strain FMB S46471 and fermented for 3 days, followed by the subsequent inoculation with Lactobacillus brevis GABA 100. After fermentation for 7 days, the fermented soybean showed approximately 1.9 g/kg GABA and exhibited higher ACE inhibitory activity than the traditional soybean product. Furthermore, several peptides in the fraction containing the highest ACE inhibitory activity were identified. The novel fermented soybean enriched with GABA and ACE inhibitory components has great pharmaceutical and functional food values.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.806-813
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• 2001

This study was carried out to investigate the effects of various kinds of commercial salts including Chunil, Hanju, Guwoon and Bamboo salts on the growth of microorganisms involved in kimchi fermentation. Among various microorganisms related to the kimchi fermentation, the growth of Leuconostoc mesenteroides, Lactobacillus plantarum, Pichia membranaefaciens and E. coli was examined. Based on the conditions of kimchi fermentation, 3% and 5% concentration of each salt were studied. Also, the temperatures at 1$0^{\circ}C$, 18$^{\circ}C$ and 37$^{\circ}C$ of the cultural condition were examined. The growth of Leuconostoc mesenteroides was inhibited depending on the reduction of cultural temperature and increase of concentration of salts. There was no considerable difference on the growth of Leu. mesenteroides in the different the kind of salts. However, the growth of Lactobacillus plantarum was strongly inhibited by the 5% concentration of Bamboo salt during incubation at 18$^{\circ}C$. When Lactobacillus plantarum was cultured at 1$0^{\circ}C$, its growth was remarkably decreased regardless of the kind and concentration of salts. In the case of Pichia membranaefaciens, Bamboo salt strongly inhibited its growth at all cultural temperatures. Apparent inhibitory effect on the growth of E. coli was observed by the Bamboo salt treatment during the incubation at 18$^{\circ}C$. At the cultural temperature of 1$0^{\circ}C$, similar results obtained.

• Journal of Life Science
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• v.22 no.2
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• pp.232-238
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• 2012

Kumjungsansung-Makgeolli$^{(R)}$ is a traditional Korean rice wine that is fermented from traditional nuruk and rice. In this study, we performed the PCR-denaturing gradient gel electrophoresis (DGGE) analysis targeting the 16S and 28S rRNA genes to characterize bacterial and fungal diversity during Makgeolli fermentation. The predominant bacteria in the PCR-DGGE profile during Makgeolli fermentation were Lactobacillus spp. (Lactobacillus curvatus, L. kisonensis, L. plantarum, L. sakei, and L. gasseri), Pediococcus spp. (P. acidilactici, P. parvulus, P. agglomerans, and P. pentosaceus), Pantoea spp. (P. agglomerans and P. ananatis), and Citrobacter freundii; these were identified on the base of analysis of 16S rRNA gene sequences. The dominant bacterium during Makgeolli fermentation was L. curvatus. The predominant fungi in PCR-DGGE profile during Makgeolli fermentation were Pichia kudriavzevii, Saccharomyces cerevisiae, Asidia idahoensis, Kluyveromyces marxianus, Saccharomycopsis fibuligera, and Torulaspora delbrueckii, and these were identified on the basis of analysis of 28S rRNA gene sequences. The dominant fungal species during Makgeolli fermentation changed from P. kudriavzevii at 0-2 days incubation to S. cerevisiae at 3-6 days incubation. This study suggests that PCR-DGGE analysis could be a suitable tool for the understanding of microbial diversity and structure during Makgeolli fermentation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.6
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• pp.971-976
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• 2002

Effect of storage temperature and packing method on the changes in pH, acidity, the levels of lactic acid bacteria, volume expansion of packages and the colorness during the fermentation of kakdugi (diced radish kimchi) were investigated. The fermentation characteristics were greatly influenced by the temperature. The pH of kakdugi fermented at 15$^{\circ}C$ was 4.10 at 3 days, while the pH of kakdugi fermented at $0^{\circ}C$ was 4.03 at 18 days. The acidity of kakdugi fermented at $0^{\circ}C$ very slowly increased compared to that of the kakdugi fermented at 15$^{\circ}C$, 1$0^{\circ}C$ or 5$^{\circ}C$. The required days to reach the acidity of 0.6% (optimally ripened state) were 6 days at 15$^{\circ}C$, 7 days at 1$0^{\circ}C$, 18 days at 5$^{\circ}C$ and 30 days at $0^{\circ}C$. Despite of different fermentation temperature, the numbers of Leuconostoc sp. in optimally ripened kakdugi were similar. However, Lactobacillus sp. in kakdugi fermented at $0^{\circ}C$ was the smallest in number. Also, the volume expansion of aluminum pack was the lowest in kakdugi fermented at $0^{\circ}C$. Both pH and acidity of the kakdugi fermented in different packing condition did not show any difference at 1$0^{\circ}C$ for 20 days, however, the color of the kakdugi was affected by a packing method. Aluminium laminate package in which Ca(OH)$_2$ Pack stuck inside resulted in decolorization of kakdugi compared with aluminum package without Ca(OH)$_2$ pack or plastic jar. It showed the lowest redness and the highest lightness and yellowness. These results indicated that fermentation at $0^{\circ}C$ could increase storage period of kakdugi with minimum growth of Lactobacillus sp., and plastic jar might relieve the problem of volume expansion and decolorization of kakdugi.

• Food Science and Preservation
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• v.31 no.1
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• pp.138-148
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• 2024

The production of poly-γ-glutamic acid (γ-PGA) and γ-aminobutyric acid (GABA) was optimized by serial fermentation of Dendropanax morbiferus extract (DME) using Bacillus subtilis HA and Lactobacillus plantarum KS2020. The 1st alkaline fermentation was performed on 60% DME including 2% glucose and 10% monosodium ʟ-glutamate (MSG) as a precursor. The 1^st fermented DME had 57 mg% tyrosine. Consequently, the 2^nd lactic acid fermentation for 5 days increased the tyrosine content of 106 mg%. The mucilage containing γ-PGA showed a high content of 3.50% on the first day of alkaline fermentation and then increased to 4.10% after 2 days. The precursor (MSG) remaining in the 1^st fermented DME was efficiently converted to GABA by the 2^nd lactic acid fermentation in the presence of 5% skim milk, 1.5% glucose and 0.5% yeast extract, resulting in the production of 18.29 mg/mL GABA. The viable cells of lactic acid bacteria increased and indicated 9.49 log CFU/mL on the fermentation for 5 days, and the acidity of co-fermented DME indicated the highest value of 1.55%. Conclusively, the serial fermented DME has multi-functional ingredients containing γ-PGA, GABA, peptides and probiotics.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.12
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• pp.1807-1813
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• 2010

To manufacture the fermented tea with hygienic quality, green tea was fermented using Bacillus subtilis, Saccharomyces cerevisiae and Lactobacillus bulgaricus and chemical composition and sensory changes were evaluated during fermentation period. The lightness of the fermented samples decreased; in contrast, redness and yellowness increased. Especially, the color change of the fermented tea using B. subtilis was higher than those of control and other samples with different microorganisms during fermentation period. Chlorophyll contents were decreased by similar level regardless of fermentation treatments. The fastest decrease of total catechins contents were found in the tea fermented with B. subtilis and significantly reduced by increase of fermentation period. However, total catechin contents of the tea fermented by L. bulgaricus were not decreased. The caffeine contents of the microbial fermented teas were more decreased than that of control, even though the decrease was slight. Sensory panelists preferred the tea fermented by B. subtilis to those of control or other fermentation treatment.