• 한국식품위생안전성학회지
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• 제32권6호
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• pp.531-535
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• 2017

본 연구에서는 김치로부터 L. mesenteroides CJNU0041을 분리하여 16S rRNA 염기서열 분석을 통해, 동정하였으며, ${\beta}$-glucosidase 활성이 우수한 것으로 나타났다. L. mesenteroides CJNU0041를 이용한 브로콜리 발효 동안 생균수와 pH 및 ${\beta}$-glucosidase 활성에 대해 분석한 결과, 발효 시간은 48 hours이 적당한 것으로 판단되었다. 또한, 발효 후 생물 전환이 일어남을 HPLC 분석을 통해 확인하였다. 그리고, L. mesenteroides CJNU0041의 브로콜리 발효물에서 C. difficile에 대한 생육 억제 효과를 확인 할 수 있었다. 따라서, 본 연구를 통해 분리된 신규 L. mesenteroides CJNU0041을 C. difficile의 생육 제어를 위한 유산균 제재화가 가능할 것으로 판단되며, 브로콜리 발효물도 다양한 식품에 적용이 가능할 것으로 사료된다.

• 한국미생물·생명공학회지
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• 제46권4호
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• pp.416-424
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• 2018

강원도에서 생산된 과일을 사용하여 식초를 제조하여, 초산 발효에 의하여 변화되는 주요 대사체 및 향기 성분을 조사하였다. 머루 복분자 식초에서는 초산 발효에 의하여 ${\text\tiny{L}}$-alanine의 함량 변화가 가장 크게 변화하였으며, 초산은 향기 성분 전체 함량 중 43%로 가장 높은 함량을 나타냈고, 초산 발효 후 ethyl acetate, isoamyl acetate 등의 에스테르 화합물의 함량이 증가하였다. 오미자 막걸리 식초의 경우 초산발효에 의하여 linalool, hexanoic acid 등이 생성되었고 테르펜류 화합물이 41.5%로 대부분을 차지하였다. 머루 복분자 식초의 경우와 유사하게 ${\text\tiny{L}}$-alanine의 함량 변화가 가장 큰 것으로 나타났다. 머루 복분자 식초에서는 ethyl acetate, 오미자 막걸리 식초에서는 감귤향을 내는 terpinel-4-ol, 꽃향기를 내는 ${\alpha}$-terpineol 등 테르펜류의 성분들이 각 식초의 향기 특성에 큰 영향을 나타내는 것으로 확인되었다.

• Journal of Microbiology and Biotechnology
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• 제22권5호
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• pp.659-667
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• 2012

2,3-Butanediol (2,3-BDO) is an organic compound with a wide range of industrial applications. Although Escherichia coli is often used for the production of organic compounds, the wild-type E. coli does not contain two essential genes in the 2,3-BDO biosynthesis pathway, and cannot ferment 2,3-BDO. Therefore, a 2,3-BDO biosynthesis mutant strain of Escherichia coli was constructed and cultured. To determine the optimum culture factors for 2,3-BDO production, experiments were conducted under different culture environments ranging from strongly acidic to neutral pH. The extracellular metabolite profiles were obtained using high-performance liquid chromatography (HPLC), and the intracellular metabolite profiles were analyzed by ultra-performance liquid chromatography and quadruple time-of-flight mass spectrometry (UPLC/Q-TOF-MS). Metabolic flux analysis (MFA) was used to integrate these profiles. The metabolite profiles showed that 2,3-BDO production favors an acidic environment (pH 5), whereas cell mass favors a neutral environment. Furthermore, when the pH of the culture fell below 5, both the cell growth and 2,3-BDO production were inhibited.

• Journal of Microbiology and Biotechnology
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• 제31권12호
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• pp.1624-1631
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• 2021

Prodigiosin as a high-valued compound, which is a microbial secondary metabolite, has the potential for antioxidant and anticancer effects. However, the large-scale production of functionally active Hahella chejuensis-derived prodigiosin by fermentation in a cost-effective manner has yet to be achieved. In the present study, we established carbon source-optimized medium conditions, as well as a procedure for producing prodigiosin by fermentation by culturing H. chejuensis using 10 L and 200 L bioreactors. Our results showed that prodigiosin productivity using 250 ml flasks was higher in the presence of glucose than other carbon sources, including mannose, sucrose, galactose, and fructose, and could be scaled up to 10 L and 200 L batches. Productivity in the glucose (2.5 g/l) culture while maintaining the medium at pH 6.89 during 10 days of cultivation in the 200 L bioreactor was measured and increased more than productivity in the basal culture medium in the absence of glucose. Prodigiosin production from 10 L and 200 L fermentation cultures of H. chejuensis was confirmed by high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) analyses for more accurate identification. Finally, the anticancer activity of crude extracted prodigiosin against human cancerous leukemia THP-1 cells was evaluated and confirmed at various concentrations. Conclusively, we demonstrate that culture conditions for H. chejuensis using a bioreactor with various parameters and ethanol-based extraction procedures were optimized to mass-produce the marine bacterium-derived high purity prodigiosin associated with anti-cancer activity.

• Journal of Microbiology and Biotechnology
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• 제31권9호
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• pp.1305-1310
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• 2021

Shikimate is a key high-demand metabolite for synthesizing valuable antiviral drugs, such as the anti-influenza drug, oseltamivir (Tamiflu). Microbial-based strategies for shikimate production have been developed to overcome the unstable and expensive supply of shikimate derived from traditional plant extraction processes. In this study, a microbial cell factory using Corynebacterium glutamicum was designed to overproduce shikimate in a fed-batch culture system. First, the shikimate kinase gene (aroK) responsible for converting shikimate to the next step was disrupted to facilitate the accumulation of shikimate. Several genes encoding the shikimate bypass route, such as dehydroshikimate dehydratase (QsuB), pyruvate kinase (Pyk1), and quinate/shikimate dehydrogenase (QsuD), were disrupted sequentially. An artificial operon containing several shikimate pathway genes, including aroE, aroB, aroF, and aroG were overexpressed to maximize the glucose uptake and intermediate flux. The rationally designed shikimate-overproducing C. glutamicum strain grown in an optimized medium produced approximately 37.3 g/l of shikimate in 7-L fed-batch fermentation. Overall, rational cell factory design and culture process optimization for the microbial-based production of shikimate will play a key role in complementing traditional plant-derived shikimate production processes.

• KSBB Journal
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• 제15권5호
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• pp.507-513
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• 2000

고지혈증 치료제인 lovastatin을 Aspergillus terreus로부터 생산하기 위해 발효조 배양설험에서 교반속도와 pH에 대한 영향올 조사하였다. 최적 교반속도는 400 rpm이었고 pH는 5.8로 유지하였을 때 lovastatin 생산이 최대였으며, 교반속도 보다 pH가 lovastatin 생산에 더 많은 영향을 미치는 것으로 나타났다 L-tryptop뼈n과 L-histi빼le의 첨가시기에 따른 lovastatin 생산량을 실험한 결과, 둘다 발효초기부터 첨가하여 배양하 는 것이 효과적이었다 L-tryptophan을 발효초기에 첨가한 최 적배지와 최적 환경조건인 교반속도 400 rpm, pH 5.8에서 회 분식 배양을 수행한 결과 기본배지를 이용하여 실험한 배양 결과보다 약 10배 정도 많은 836 mg/L이었고, 생산성은 3.5 mg/L.hr였다

• Animal Bioscience
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• 제34권8호
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• pp.1331-1341
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• 2021

Objective: This study aimed to determine the effects of replacing cassava chips with broken rice in a fermented total mixed ration diet on silage quality, feed intake, ruminal fermentation, growth performance, and carcass characteristics in the final phase of fattening beef cattle. Methods: Eighteen Charolais-Thai native crossbred steers (average initial body weight: 609.4±46 kg; average age 31.6 mo) were subjected to three ad libitum dietary regimes and were maintained in individual pens for 90 d before slaughter. The experimental design was a randomized complete block design by initial age and body weight with six replicates. The dietary regimens used different proportions of broken rice (0%, 16%, and 32% [w/w] of dry matter [DM]) instead of cassava chips in a fermented total mixed ration. All dietary treatments were evaluated for in vitro gas production and tested in in vivo feeding trials. Results: The in vitro experiments indicated that organic matter from broken rice was significantly more digestible than that from a cassava-based diet (p<0.05). Silage quality, nutrient intake, ruminal fermentation characteristics, carcass fat thickness, and marbling score substantially differed among treatments. The ruminal total volatile fatty acids, propionate concentration, dietary protein intake, and digestibility increased linearly (p<0.05) with broken rice, whereas acetate concentration and the acetate:propionate ratio decreased linearly (p<0.05) with broken rice (added up to 32 g/kg DM). Broken rice did not influence plasma metabolite levels or growth performance (p>0.05). However, the marbling score increased, and the carcass characteristics improved with broken rice. Conclusion: Substitution of cassava chips with broken rice in beef cattle diets may improve fattened beef carcass quality because broken rice increases rumen fermentation, fatty acid biosynthesis, and metabolic energy supply.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.223-227
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• 2003

Mevinolic acid (MA), a secondary metabolite produced by a filamentous fungus Aspergillus terreus, is acidic form of lovastatin which has been identified as a powerful cholesterol-lowering agent in humans. When immobilized cell culture was performed, MA production was about 5.3-fold higher than the parallel suspended cell culture. Although the immobilized cells proliferated slowly during exponential in comparison with the suspended cells, oxygen uptake rate and oxygen mass transfer coefficient of the immobilized cell culture were about 1.3- and 2.5- fold higher respectively than those of the parallel suspended cell culture. From these results, it was concluded that MA biosynthesis was closely dependent on the cell growth rate, morphology and oxygen availability.

• Asian-Australasian Journal of Animal Sciences
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• 제14권8호
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• pp.1085-1089
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• 2001

Metabolites, such as isopropyl alcohol (IPA) produced by rumen fermentation, were intravenously infused into a jugular vein of goats during feeding to explore the mechanism and roles of IPA in ruminating behavior (number of boli and ruminating time). Three female goats were confined in metabolism cages with a stanchion, The ruminating behavior measured by the number of ruminations, ruminating time, number of remastications, and remasticating time decreased (p<0,05) with intravenous IPA infusion. The IPA concentrations and VFA concentrations increased in the blood circulation. Our data suggest that sensitive receptors of rumination to IPA are more likely to be in an area such as the brain stem where they can respond to blood metabolite levels.

• Journal of Microbiology and Biotechnology
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• 제18권1호
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• pp.107-109
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• 2008

Medicinal fungi, Phellinus linteus and Inonotus xeranticus, produce a cluster of yellow pigment in their fermentation broth that acts as an important element of biological activity. The pigment is composed of diverse polyphenols with a styrylpyrone moiety, mainly hispidin and its dimers, 3,14'-bihispidinyl, hypholomine B, and 1,1-distyrylpyrylethan. Although dimeric hispidins were proposed to be biosynthesized from two molecules of monomer via oxidative coupling by ligninolytic enzymes, laccase and peroxidase, the details of this process remain unknown. In this preliminary study, we attempted to achieve enzymatic synthesis of the hispidin dimer from hispidin by using commercially available horseradish peroxidase (HRP). Consequently, a hispidin dimer, 3,14'-bihispidinyl, was synthesized, whereas the other dimers, hypholomine B and 1,1-distyrylpyrylethan, were not produced. This result suggested that the oxidative coupling at the C-3 and C-14' positions of hispidins was dominant in the process of dimerization by HRP, and indicated that additional catalysts or substrates would be needed to synthesize other hispidin dimers present in the fungal metabolite.