• Journal of Applied Biological Chemistry
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• 제63권4호
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• pp.429-437
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• 2020

This study aimed to investigate the change in physicochemical properties and lactic acid bacterial communities during kimchi fermentation at different temperatures (8, 15, and 25 ℃) using two molecular genetics approaches, multiplex polymerase chain reaction and 16S rRNA gene sequencing. The pH during fermentation at 8, 15, and 25 ℃ decreased from 6.17 on the initial fermentation day to 3.92, 3.79, and 3.48 after 54, 30, and 24 days of fermentation, respectively, while the acidity increased from 0.24% to 1.12, 1.35, and 1.54%, respectively. In particular, the levels of lactic acid increased from 3.74 g/L on the initial day (day 0) to 14.43, 20.60, and 27.69 g/L during the fermentation after 24, 18, and 12 days at 8, 15, and 25 ℃, respectively, after that the lactic acid concentrations decreased slowly. The predominance of lactic acid bacteria (LAB) in the fermented kimchi was dependent on fermentation stage and temperature: Lactobacillus sakei appeared during the initial stage and Leuconsotoc mesenteroides was observed during the optimum-ripening stage at 8, 15, and 25 ℃. Lac. sakei and Lactobacillus plantarum grew rapidly in kimchi produced at 8, 15, and 25 ℃. In addition, Weissella koreensis first appeared at days 12, 9, and 6 at 8, 15, and 25 ℃ of fermentation, respectively. This result suggests that LAB population dynamics are rather sensitive to environmental conditions, such as pH, acidity, salinity, temperature, and chemical factors including free sugar and organic acids.

• 생명과학회지
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• 제22권11호
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• pp.1463-1469
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• 2012

전통발효식품인 고추장의 기능성을 부가하고 맛과 기호성을 개선하기 위하여 토마토 퓨레조청을 첨가한 고추장을 최적발효조건을 설정하기 위해 소금의 농도를 달리하여 GCJ 14, 16, 18, 20의 조건으로 제조한 후 발효하여 고추장의 이화학적 성분의 변화로 발효의 최적조건을 설정하였으며, 기능성 성분인 라이코펜의 함량을 분석하였다. 그 결과 토마토 퓨레 조청 함유 고추장의 pH의 변화는 발효기간동안 감소하였으며, 당도는 감소하였다 증가를 반복하였으며, 수분과 염도, 색도는 유의적인 변화를 나타내지 않았다. 미생물의 변화는 발효가 진행됨에 따라 총균수와 유산균수는 증대되었으며, 총균수 대비 유산균의 생성비율은 GCJ 18와 GCJ 20조건에서 높은 비율을 확인하였다. 토마토 기능성 성분인 라이코펜의 함량의 변화는 발효과정 동안 유의적 변화를 나타내지 않았다. 그리고 제조된 고추장의 조단백질, 조지방, 조회분, 탄수화물의 일반성분함량의 변화와 맛, 기호성 등의 관능검사에서 GCJ 20에서 가장 발효에 적합한 조건으로 판단된다. 따라서 토마토 퓨레조청 함유 고추장으로 현대인의 기호에 맞으면서 기능성이 부과된 고추장의 개발의 가능하다고 사료된다.

• 미생물과산업
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• 제12권1호
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• pp.15-22
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• 1986

Chemical production by anaerobic bacterial fermentations was an important microbiological topic in the past due to both fundamental and applied aspects related to acetone-butanol production prior to its replacement by chemical synthetic routes from petroleum. Presently, the depletion and price-escalation of petroleum has regenerated a great interest in the potential of anaerobic bacteria to transform the renewable resouces such as biomass and wastes into chemical feed-stocks and fuels.

• Asian-Australasian Journal of Animal Sciences
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• 제27권11호
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• pp.1562-1570
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• 2014

The effects of Lactobacillus mucosae (L. mucosae), a potential direct fed microbial previously isolated from the rumen of Korean native goat, on the rumen fermentation profile of brewers grain were evaluated. Fermentation was conducted in serum bottles each containing 1% dry matter (DM) of the test substrate and either no L. mucosae (control), 1% 24 h broth culture of L. mucosae (T1), or 1% inoculation with the cell-free culture supernatant (T2). Each serum bottle was filled anaerobically with 100 mL of buffered rumen fluid and sealed prior to incubation for 0, 6, 12, 24, and 48 h from which fermentation parameters were monitored and the microbial diversity was evaluated. The results revealed that T1 had higher total gas production (65.00 mL) than the control (61.33 mL) and T2 (62.00 mL) (p<0.05) at 48 h. Consequently, T1 had significantly lower pH values (p<0.05) than the other groups at 48 h. Ammonia nitrogen ($NH_3$-N), individual and total volatile fatty acids (VFA) concentration and acetate:propionate ratio were higher in T1 and T2 than the control, but T1 and T2 were comparable for these parameters. Total methane ($CH_4$) production and carbon dioxide ($CO_2$) were highest in T1. The percent DM and organic matter digestibilities were comparable between all groups at all times of incubation. The total bacterial population was significantly higher in T1 (p<0.05) at 24 h, but then decreased to levels comparable to the control and T2 at 48 h. The denaturing gradient gel electrophoresis profile of the total bacterial 16s rRNA showed higher similarity between T1 and T2 at 24 h and between the control and T1 at 48 h. Overall, these results suggest that addition of L. mucosae and cell-free supernatant during the in vitro fermentation of dried brewers grain increases the VFA production, but has no effect on digestibility. The addition of L. mucosae can also increase the total bacterial population, but has no significant effect on the total microbial diversity. However, inoculation of the bacterium may increase $CH_4$ and $CO_2$ in vitro.

• Mycobiology
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• 제47권2호
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• pp.250-255
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• 2019

In the present study, we aimed to determine the cause of surface film formation in three rice vinegars fermented using the traditional static fermentation method. The pH and total acidity of vinegar were 3.0-3.3 and 3.0-8.7%, respectively, and acetic acid was the predominant organic acid present. Colonies showing a clear halo on GYC medium were isolated from the surface film of all vinegars. Via 16S rDNA sequencing, all of the isolates were identified as Acetobacter pasteurianus. Furthermore, field-emission scanning electron microscopy analysis showed that the bacterial cells had a rough surface, were rod-shaped, and were ${\sim}1{\times}2{\mu}m$ in size. Interestingly, cells of the isolate from one of the vinegars were surrounded with an extremely fine threadlike structure. Thus, our results suggest that formation of the surface film in rice vinegar was attributable not to external contamination, to the production of bacterial cellulose by A. pasteurianus to withstand the high concentrations of acetic acid generated during fermentation. However, because of the formation of a surface film in vinegar is undesirable from an industrial perspective, further studies should focus on devising a modified fermentation process to prevent surface film formation and consequent quality degradation.

• Preventive Nutrition and Food Science
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• 제1권1호
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• pp.23-29
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• 1996

This study was conducted to investigate the changes in chemical, microbial and sensory characteristics, and antimutagenicity of buchu(leek, Allium odorum) kimchi during fermentation at 15$^{\circ}C$. Reducing sugar contents and pH of buchu kimchi were decreased during the fermentation. The reduction rate of reducing sugar of glutinous rice paste and shrimp added buvhu kimchi(GSBK) was faster than those of control buchu kimchi(CBK) and glutious rice paste added bucku kimchi(GBK). Acidity increased rapidly until 4 days,a nd optimum acidity (0.6%) of bucku kimchi was reached within 2 day. Also total bacterial and lactic acid bacterial counts greatly increased after 4 days of the fermentation. The numbers of lactic acid bacteria after 8 day- fermentation in CBK and GSBK, and 10 day-fermentation in GBK were the highest values, 4.5$\times${TEX}$10^{8}${/TEX} CFU/ml, 4.8$\times${TEX}$10^{8}${/TEX} CFU/ml and 6.1$\times${TEX}$10^{8}${/TEX} CFU/ml, respectively. In the sensory evaluation, appearance of sample was good at 0 day, taste from overall quality of buchu kimchi were asquired the highest values at 6th day. The methanol extracts from buchu kimchi(GBK) showed antimutagenicity against aflatoxin {TEX}$B_{1}${/TEX}({TEX}$AFB_{1}${/TEX})in Salmonella typhimurium TA100. The inhibition ration were 58~69% with treatment of the 5% methanol extracts, and when the adding concentration increased the effect increased.

• Journal of Veterinary Science
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• 제24권2호
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• pp.27.1-27.15
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• 2023

Background: The relationships between the postpartum subacute ruminal acidosis (SARA) occurrence and predicted bacterial functions during the periparturient period are still not clear in Holstein cows. Objectives: The present study was performed to investigate the alterations of rumen fermentation, bacterial community structure, and predicted bacterial functional pathways in Holstein cows. Methods: Holstein cows were divided into the SARA (n = 6) or non-SARA (n = 4) groups, depending on whether they developed SARA during the first 2 weeks after parturition. Reticulo-ruminal pH was measured continuously during the study period. Reticulo-ruminal fluid samples were collected 3 weeks prepartum, and 2 and 6 weeks postpartum, and blood samples were collected 3 weeks before, 0, 2, 4 and 6 weeks postpartum. Results: The postpartum decline in 7-day mean reticulo-ruminal pH was more severe and longer-lasting in the SARA group compared with the non-SARA group. Changes in predicted functional pathways were identified in the SARA group. A significant upregulation of pathway "PWY-6383" associated with Mycobacteriaceae species was identified at 3 weeks after parturition in the SARA group. Significantly identified pathways involved in denitrification (DENITRIFICATION-PWY and PWY-7084), detoxification of reactive oxygen and nitrogen species (PWY1G-0), and starch degradation (PWY-622) in the SARA group were downregulated. Conclusions: The postpartum SARA occurrence is likely related to the predicted functions of rumen bacterial community rather than the alterations of rumen fermentation or fluid bacterial community structure. Therefore, our result suggests the underlying mechanisms, namely functional adaptation of bacterial community, causing postpartum SARA in Holstein cows during the periparturient period.

• Asian-Australasian Journal of Animal Sciences
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• 제27권4호
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• pp.511-517
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• 2014

This study examined the effects of bacterial inoculants on chemical composition and fermentation indices of barley silage. Barley forage (Youngyang) was harvested at 24% dry matter (DM) and wilted to 47.9% DM. The wilted barley forage was chopped to 3-5 cm length and applied with no inoculant (CON), L. plantarum ($1{\times}10^{10}cfu/g$, LP) or Effective Microorganisms ($0.5{\times}10^9cfu/g$, EM). Then the forages were ensiled in four replications for each treatment in 20 L mini silos and stored for 100 days. The contents of crude protein and ether extract were higher in CON silage ensiled for 100-d, while the contents of DM and crude ash were higher in EM silage (p<0.05). The contents of ADF, NDF and hemicellulose as well as the in vitro DM digestibility were not affected by microbial inoculation (p>0.05). The pH, ammonia-N concentration and lactate to acetate ratio were higher (p<0.05) in CON silage, while lactate concentrations were higher (p<0.05) in CON and LP silage. Acetate concentration and lactic acid bacteria was increased (p<0.05) by both inoculants (LP and EM), but propionate concentration and yeast was increased (p<0.05) by EM and LP, respectively. These results indicated that the fermentation quality of barley silage was improved by the application of bacterial inoculants.

• 한국미생물·생명공학회지
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• 제42권2호
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• pp.121-130
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• 2014

Bacteria 군집 차이를 이용한 신속한 한국산 및 중국산 김치 원산지 판별 가능성의 검토를 위하여 Terminal Restriction Fragment Length Polymorphism (T-RFLP) 분석법을 적용하였다. T-RFLP 분석은 김치발효에 관여하는 주요 유산균의 빠르고, 재현성 있는 검출에는 효과적이었지만, 종(species) 수준에서의 미생물 확인에는 한계를 가지고 있어 한국산 및 중국산 김치에 특이적으로 존재하는 bacteria의 검출에는 부적합한 것으로 평가되었다. T-RFLP를 적용한 발효과정 중의 한국산 및 중국산 김치에 존재하는 bacteria 군집 천이 분석은 비슷한 양상으로 나타났고, Bacillus 속이 발효 후기까지 검출되었다. 또한 Bacillus 속은 발효 후기에 포자를 형성하는 것으로 확인되었다.

• 한국초지조사료학회지
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• 제41권4호
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• pp.259-266
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• 2021

The present study was aimed to estimate the effect of ensiling period and bacterial inoculants on chemical compositions and fermentation characteristics on rye silage harvested at delayed stage. Rye (Secale cereale L.) was harvested after 20 days of heading stage (29.4% dry matter, DM). The harvested rye forage was applied with different inoculants following: applications of distilled water (CON), Lactobacillus brevis (LBB), Leuconostoc holzapfelii (LCH), or mixture of LBB and LCH at 1:1 ratio (MIX). Each forage was ensiled into 20 L mini bucket silo (5 kg) for 50 (E50D) and 100 (E100D) days in triplicates. The E50D silages had higher in vitro digestibilities of DM (IVDMD, p<0.001) and neutral detergent fiber (IVNDFD, p=0.013), and lactate (p=0.009), and acetate (p=0.011) than those of E100D, but lower pH, lactic acid bacteria (LAB), and yeast. By inoculant application, LCH had highest IVDMD and IVNDFD (p<0.05), while MIX had highest lactate and lowest pH (p<0.05). The CON and LCH in E50D had highest LAB and yeast (p<0.05), whereas LBB in E100D had lowest (p<0.05). Therefore, this study concluded that LCH application improved the nutrient digesbility (IVDMD and IVNDFD) of lignified rye silage, and longer ensiling period for 100 days enhanced the fermentation characteristics of silage compared to ensiling for 50 days.