• 한국식생활문화학회지
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• 제34권2호
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• pp.208-216
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• 2019

Leuconostoc spp. are generally utilized as kimchi starters, because these strains are expected to have beneficial effects on kimchi fermentation, including improvement of sensory characteristics. Here, we developed a detection method for verifying the presence of the kimchi starter Leuconostoc mesenteroides WiKim33, which is used for control of kimchi fermentation. A primer set for multiplex polymerase chain reaction was designed based on the nucleotide sequence of the plasmids in strain WiKim33, and their specificity was validated against 45 different strains of Leuconostoc spp. and 30 other strains. Furthermore, the starter strain consistently tested positive, regardless of the presence of other bacterial species in starter kimchi during the fermentation period. Our findings showed that application of a strain-specific primer set for strain WiKim33 presented a rapid, sensitive, and specific method for detection of this kimchi starter strain during natural kimchi fermentation.

• Biotechnology and Bioprocess Engineering:BBE
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• 제1권1호
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• pp.1-8
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• 1996

Fermentation processes for the production of butanol had an economic importance in the first part of this century. Today butanol is commercially produced from the Oxo reaction of propylene because relatively low priced propylene during the cracking of petroleum. Efforts have been made during the past decade or two to improve the productivity of butanol fermentation processes. It includes strain improvements, continuous fermentation processes, cell immobilization and simultaneous product separation. This review introduces a new butanol fermentation process using pervaporative product separation and a new bacterial strain producing less amount of organic acids. This review also compares the new process with chemical processes. This kind of new fermentation process may be able to compete with the chemical synthesis of butanol and revitalize the butanol fermentation process.

• Journal of Microbiology and Biotechnology
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• 제2권2호
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• pp.108-114
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• 1992

The fermentative characteristics in ethanol production from lactose, with increased ethanol tolerance, of a fusant yeast strain constructed by protoplast fusion of Saccharomyces cerevisiae and Kluyveromyces fragilis were studied. The ethanol tolerance of this strain was increased to 8.0%, compared with the parent K. fragilis. During batch ethanol fermentation the optimal cultivation conditions for this fusant yeast were an initial pH of 4.5, a culture temperature $30^\circ{C}$. stirring at 100 rpm without aeration in 10% lactose medium (supplied with 1.0% yeast extract). Using this fusant strain in whey fermentation to ethanol, maximum ethanol production reached 3.41% (w/v) (theoretical yield; 66.7%) after a 48 hour cultivation period.

• Journal of Microbiology and Biotechnology
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• 제9권6호
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• pp.789-793
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• 1999

The effect of acetic acid formation deficiency on recombinant E. coli fermentation was investigated using a mutant strain deficient in acetic acid formation. A mutant strain which does not grow under anaerobic conditions was isolated. The acetic acid production in this strain was negligible in aerobic batch fermentation. The cloned-gene expression in the mutant strain was higher than the wild-type strain. Fed-batch fermentations with controlled specific growth rates were carried out in order to compare the cloned-gene expression between the wild-type and the mutant strains. The expression decreased along with the specific growth rate in both strains. The cloned-gene expression in the mutant strain was 60% higher than in the wild-type strain at the same specific growth rate.

• Journal of Microbiology and Biotechnology
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• 제4권1호
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• pp.7-12
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• 1994

A yeast strain secreting glucoamylase was transformed with an expression vector (pMS12) containing the promoter of yeast alcohol dehydrogenase I gene ADC1, mouse salivary $\alpha$-amylase cDNA, and a segment of yeast $21\mu m$ plasmid. The transformed strain could produce ethanol from starch (4%, w/v) through a direct one-step process with the conversion efficiency of 93.2%, during 5 days of fermentation, while the original, untransformed strain exhibited a conversion efficiency of 38.1% under the same condition. When the regulatory site of the ADC1 promoter region was removed, the production of ethanol increased to 29~37% in the presence of exogenous 3%(v/v) ethanol in the fermentation medium.

• KSBB Journal
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• 제28권6호
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• pp.400-407
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• 2013

The growth characteristics and production of color pigments by Monascus strains were investigated during liquid culture, and production of monacolin K in red mold rice was carried out by solid state fermentation. Four different Monascus ruber strains were cultured in potato dextrose yeast extract broth (PDYB) media at $25^{\circ}C$ for 15 days. The high producing strain for red pigment was not corresponded to the strain for yellow pigment. Production of red pigment was high in the strain causing the fast pH change in culture broth. Production of monacolin K in red mold rice by solid state fermentation was influenced by a combination of wet cell weight and spore density in inoculum by liquid culture. Most strains showed the high production of monacolin K in red mold rice, when submerged fermentation was carried out for 5 days as inoculum for solid state fermentation. These results suggest that submerged fermentation period of inoculum have an effect on the production of monacolin K in red mold rice by solid state fermentation, and monacolin K in red mold rice could be increased by controlling the condition of submerged fermentation for inoculum.

• 한국응용과학기술학회지
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• 제39권5호
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• pp.632-643
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• 2022

Although probiotics have been shown to improve health when consumed, recent studies have reported that they can cause unwanted side effects due to bacterial-human interactions. Therefore, the importance of prebiotics that can form beneficial microbiome in the gut has been emphasized. This study isolated and identified bacteria capable of producing biopoymer as a candidate prebiotic from traditional fermented foods. The isolated and identified strain was named WCYSK01 (Wissella sp. strain YSK01). The composition of the medium for culturing this strain was prepared by dissolving 3 g K₂HPO₄, 0.2 g MgSO₄, 0.05 g CaCl₂, 0.1 g NaCl in 1 L of distilled water. The LMBP(low molecular weight biopoymers) produced when fermentation was performed with sucrose and maltose as substrates were mainly consisted of DP3 (degree of polymer; isomaltotriose), DP4 (isomaltotetraose), DP5 (isomaltopentaose), and DP6 (isomaltoheptaose). The optimization of LMBP (low molecular weight of biopolymer) production was performed using the response surface methodology. The fermentation process temperature range of 18 to 32℃, the fermentation medium pH in the range of 5.1 to 7.9. The yield of LMBP production by the strain was found to be significantly affected by q fermentation temperature and pH. The optimal fermentation conditions were found at the normal point, and the production yield was more than 75% at pH 7.5 and temperature of 23℃.

• Journal of Microbiology and Biotechnology
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• 제10권6호
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• pp.776-783
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• 2000

Various alcohol yeast strains have been isolated from main mashes of Korean traditional liquors, and their genetic diversities were previously reported [23]. In this study, the strain SHY111, showing the highest alcohol production, was tested for its fermentation and sporulation characteristics. Additionally, its haploid cells were isolated and tested for their growth and fermentation patterns. The strain was identified as Saccharomyces cerevisiae based on its morphological and physiological characteristics. The sequences of the ITS(internal transcribed spacer) and 5.8S rDNA regions of S. cerevisiae SHY111 were found to be identical to those of S. cerevisiae that was obtained from through the yeast genome project. The maximum fermentation ratio obtained by the strain SHY111 (96.7%) was almost the same as that by S. cerevisiae Balyun No. 1 (96.5%) that was a little higher than that by S. cerevisiae KCCM11215(95.8%). The strain was induced for sporulation in a sporulation liquid medium using log phase cells grown in different types of pre-sporulation media, and its haploid cells were obtained by spore dissection using a micromanipulator. The majority of the spores formed a small colony on a YPD agar plate, and the haploid yeast cells derived from the strain SHY111 showed a variety of growth and alcohol fermentation patterns. It was proposed that the fermentation patterns were related to their growth phenotypes in the most haploid strains, but possible not in some strains.

• 한국식품저장유통학회지
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• 제17권2호
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• pp.174-181
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• 2010

참다래로 만든 'Hayward' 와인 제조에 적합한 효모 선발을 위해서 3종의 효모에 의한 발효과정에서의 물리화학적 특성 변화를 조사 분석하였다. 사용된 효모는 Saccharomyces cerevisiae Gervin No.5 strain (GVN), S. bayanus Lavin strain EC1118 (EC1118), 그리고 S. cerevisiae Red star Davis No.796 (No.796)은 와인 발효에 가장 적합하여 상업적으로 이용되고 있는 효모이다. 이 세 효모에 의해 발효된 샘플의 당도 함량은 비슷하게 감소하였으나, 알코올 생산량만 발효 첫 주에 큰 차이가 있었다. 효모중 GVN이 13.8%로 알콜농도가 가장 높았고, 반면에 No.796과 EC1118은 각각13.0%와 12.5%로 상대적으로 알콜함량이 낮았다. 관능평가에서 GVN은 높은 산과 높은 알콜함량을 가지고 있고, 강한 풍미와 쓴맛을 가진 것으로 평가되었다. No.796은 GVN과 유사하지만 낮은 알콜함량과 함께 단맛이 있었다. EC1118은 높은 풍미, 단맛과 낮은 알콜함량으로 부드러운 맛으로 평가되었다. EC1118에 의해 발효된 와인 의 총페놀과 항산화 활성은 다른 효모보다 높았다. 따라서 본 연구에서EC1118이 최적의 효모로 선발되었다. 다른 2종의 효모를 사용한 참다래 발효 와인은 각각 다른 품질 특성을 나타내었다. EC1118효모는 참다래 발효에 가장 바람직한 특성을 가지고 있었다. 이러한 특성은 주로 총페놀과 항산화 활성과 같은 건강기능성과 높은 관능적 기호도를 가지고 있었다.

• 한국미생물·생명공학회지
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• 제30권4호
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• pp.425-429
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• 2002

Saccharomyces cerevisiae KNU5377 was examined to assay the recovering capacity against heat and other stressors. Along with a particular fermentation ability that is able to produce ethanol even at high temperature such as $40^{\circ}C$ with a comparable rate to the fermentation at $33^{\circ}C$, this strain also exhibited higher viability than a reference strain owing to its own thermotolerance that conferred the survival after the severe heat shock at $60^{\circ}C$ for 30 minutes. Furthermore, this strain showed outstanding tolerances against $H_2O_2$, ethanol and some chemical compounds. But, especially due to the thermotolerance, this strain has been suspected of other species of yeast. However, ITS (internally transcribed spacer) 1 and 2 sequencing data confirmed this strain was a typical strain of S. cerevisiae. The outstanding tolerances to various environmental stressors Indicate this S. cerevisiae KNU5377 is enough to use both as an on-site potential strain for world-wide alcohol fermentation industry and as a model strain for researches into the routes to acquire the tolerance to various stressors.