• 한국미생물·생명공학회지
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• 제28권1호
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• pp.33-38
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• 2000

In order to produce ascorbic acid-2-phosphate from ascorbic acid, bacteria capable of transforming ascorbic acid to ascorbic acid-2-phosphate were isolated from soils and the stock cultures in our laboratory. Among them, a newly isolated bacterium LSH-3 having the best ability of producing ascorbic acid-2-phosphate was selected and partially identified as Pseudomonas sp. The optimum conditions for the production of ascorbic acid-2-phosphate from ascorbic acid and using its resting cells as the source os enzyme were investigated. The results were summarized as follows: The optimum cultivation time and the cell weight for the production of ascorbic acid-2-phosphate was 14 hours and 100g/I(wet weight), respectively. And 0.1%(v/v) Trition X-100 was the most effective surfactant. The optimum concentrations of ascorbic acid and pyrophosphate were 400mM and 500mM, respectively, which led to produce 14.54g/I of ascorbic acid-2-phosphate. The most effective buffer was 50mM sodium acetate. The optimum pH and temperature were 4.5 and $40^{\circ}C$, respectively. Under the above conditions, 17.71 g/I of ascorbic acid-2-phosphate was produced from ascorbic acid after 32 hour-incubation, which corresponded to 17.5% of conversion rate based on ascorbic acid.

• KSBB Journal
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• 제10권4호
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• pp.370-373
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• 1995

S.cerevisiae에 의한 에딴올 발효에셔 생성되는 부산물 인 acetic acid, acetaldehyde, glycerol, lactic acid, formic acid가 세포성장과 에탄올 생성에 미치는 영향을 고찰하였다. Acetic acid와 acetaldehyde 를 발효액 내에 투입하였을 때, 세포생장은 저해되 었으나, 에탄올 생성은 증가되었다. 한편, glycerol 과 lactic acid는 세포성장과 에탄올 생산에 거의 영 향이 없었다. Acetic acid와 acetaldehyde는 비성장 속도를 줄임과 동시에 정체기를 늘염으로써 세포성장을 저해하였다. 에단올 수율은 첨가된 acetic acid 와 acetaldehyde 농도에 비례하여 증가하였고, acetic acid $3g/\ell$, acetaldehyde $2g/\ell$ 일 때, 최대가 되었다.

• 한국미생물·생명공학회지
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• 제23권1호
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• pp.6-11
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• 1995

In order to screen microorganism producing lactic acid with high productivity from nature, we used a medium containing 100 g/l glucose and selected several microorganisms producing more than 80 g/l L-lactic acid. We investigated their physiological characteristics and compared them. The best microorganism was identified as Lactobacillus casei subsp. rhamnosus. The optimum pH for growth and production of lactic acid was 6.0 and this strain showed the highest growth rate at around 30$\circ$C , but the optimum temperature for lactic acid production was 45$\circ$C . The growth was inhibited proportionally from 50 g/l to 300 g/l of glucose and the maximal cell mass increased according to increasing the concentration of corn steep liquor (CSL) protein up to 30 g/l. In batch fermentation for lactic acid production, we produced 128 g/l L-lactic acid with 20 g/l CSL protein and 150 g/l glucose in 35 hours. In pH-stat fed-batch fermentation, we were able to produce 183 g/l L-lactic acid.

• Current Research on Agriculture and Life Sciences
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• 제31권1호
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• pp.25-29
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• 2013

As a specialty oil, furan fatty acids have gained special attentions since they are known to play important roles in biological systems including human. Although several studies reported chemical synthesis of furan fatty acids, their synthesis consisted of complicated chemical multistep with chemical catalysts. Recently, a simple one-step heat treatment method was developed to produce a novel furan fatty acid, 7,10-epoxy-octadeca-7,9-dienoic acid (7,10-EODA) from a dihydroxyl fatty acid 7,10-dihydroxy-8(E)-octadecenoic acid (DOD). In this report we studied about optimization of environmental conditions for the maximum production of 7,10-EODA from DOD by heat treatment. Production of 7,10-EODA was maximized at over $85^{\circ}C$ for at least over 48 hour in hexane. Solvent volume for maximum production should be over 300 mL per 10 mg DOD.

• Preventive Nutrition and Food Science
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• 제7권1호
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• pp.37-42
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• 2002

Factors affecting the production of bacterial cellulose and organic acids in Kombucha fermentation were investigated. Kombucha was obtained by the fermentation (for 12 days at 3$0^{\circ}C$) of the green/black tea extract, supplemented with 10% white sugar, using an Oriental tea fungus as starter. Hitgher initial pH increased acid production with decreased cellulose production. With a cellulose pellicle or tea fungus broth as a starter, a 1~3 mm thick cellulose layer developed as a top layer every four days, and was removed subsequently while continuing fermentation. Addition of 30 mL tea fungus broth (13%, v/v) in Kombucha fermentation resulted in maximum production of a cellulose pellicle, indicating weak acid production. Yield of cellulose production at an early stage of fermentation was also higher when Kombucha was inoculated with a cellulose pellicle. In fact, addition of 1% (v/v) alcoholic beverage in the Kombucha fermentation activated the cellulose production, coupled with four times higher acid production.

• Journal of Microbiology and Biotechnology
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• 제18권3호
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• pp.417-426
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• 2008

The effect of increasing levels of proclavaminate amidino hydrolase (Pah) on the rate of clavulanic acid production in Streptomyces clavuligerus ATCC 27064 was evaluated by increasing dosoge of a gene (pah2) encoding Pah. A strain (SMF5703) harboring a multicopy plasmid containing the pah2 gene showed significantly retarded cell growth and reduced clavulanic acid production, possibly attributable to the deleterious effects of the multicopy plasmid. In contrast, a strain (SMF5704) carrying a single additional copy of pah2 introduced into chromosome via an integrative plasmid showed enhanced production of clavulanic acid and increased levels of pah2 transcripts. Analysis of transcripts of other genes involved in the clavulanic acid biosynthetic pathway revealed a pattern similar to that seen in the parent. From these results, it appears that clavulanic acid production can be enhanced by duplication of pah2 through integration of a second copy of the gene into chromosome. However, increasing the copy number of only one gene, such as pah2, does not affect the expression of other pathway genes, and so only modest improvements in clavulanic acid production can be expected. Flux controlled by Pah did increase when the copy number of pah2 was doubled, suggesting that under these growth conditions, Pah levels may be a limiting factor regulating the rate of clavulanic acid biosynthesis in S. clavuligerus.

• 한국식품과학회지
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• 제22권2호
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• pp.183-191
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• 1990

본 연구에서는 농축대두단백으로 만든 두유에 4종의 유제품을 여러 가지 농도로 가하고 5종의 젖산균(Lactobacillus 4종, Leuconostoc 1종)의 산생성과 생육을 관찰한 후에 유제품을 첨가하여 만든 대두요구르트의 관능성을 조사하였다. 두유에 첨가된 유제품의 농도를 증가시킴에 따라 젖산균의 산생성은 점차로 증가하였으며, 첨가된 유제품 가운데 유청분말이나 탈지분유가 전지분유나 조제분유보다 젖산균의 산생성을 촉진시켰다. 특히 유청분말은 유제품의 첨가농도가 낮을 때 산생성 촉진효과가 높았으며, 전지분유는 산생성 촉진효과가 유제품 가운데 가장 낮았다. 젖산균 산생성의 경시적인 변화를 보면 표준시료(포도당 첨가 시료). 유제품 첨가 시료 어느 경우나 배양시간이 경가함에 따라 산생성은 현저하게 증가하였다. 배양 초기부터 12시간까지는 포도당 시료의 산생성이 가장 높았으나 18시간 이후에는 유청분말 시료의 산생성이 가장 높았다. 전지분유 시료는 전 실험 기간에 걸쳐서 산생성이 가장 낮았다. 대두요구르트의 관능성을 보면 전지분유 시료와 탈지분유 시료의 향미(香味)는 표준시료(포도당 첨가시료)보다 우수하였으나 유청분말 시료와 조제분유 시료의 향미(香味)는 표준시료보다 저조하였다.

• 한국식품과학회지
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• 제19권2호
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• pp.151-156
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• 1987

대두, 탈지대두, 농축대두단백 또는 분리대두단백으로 각각 두유를 만들고 여기에 Lactobacillus acido-philus, L.bulgaricus, L.casei, Leuconostoc mesenter-oides, Streptococcus lactis 를 각각 접종하여 이들 대두단백질이 젖산균의 생육과 산생성에 미치는 영향에 차이가 있는가를 관찰하였다. 산생성도를 보면 L.acido-philus의 경우는 두유에서 산생성이 가장 높았으나, 나머지 4종의 젖산균에서는 탈지두유에서 산생성이 가장 높았으며, 5종의 젖산균 어느 경우나 SPI두유에서는 산생성이 현저하게 낮았다. 두유에 yeast extract (0.5%)를 첨가했을 때 대두단백질의 형태에 관계없이 모든 시료에서 젖산균에 의한 산생성이 촉진되었으며, 5종의 젖산균 가운데 특히 L.acidophilus에 의한 산생성이 현저하게 촉진되었다. 두유의 고형분 농도를 증가 시킴에 따라 L.acidophilus와 L.bulgaricus의 생육과 산생성이 대체적으로 촉진되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제17권9호
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• pp.1255-1259
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• 2004

The objective of this study was to evaluate the effects of halogenated compounds, organic acids, unsaturated fatty acids and their mixtures on in vitro methane production and fermentative characteristics of mixed rumen microorganisms. Agents used in two in vitro experiments were bromoethanesulfonic acid (BES) and pyromellitic diimide (PMDI) as halogenated compound, fumarate and malate as organic acid, and linoleic acid and linolenic acid as unsaturated fatty acid sources. Ruminal fluid collected from a Holstein steer fed tall fescue and concentrate mixtures was incubated at $39^{\circ}C$ for 48 h with addition of those materials. Single supplementation of halogenated compounds, organic acids or unsaturated fatty acids decreased in vitro methane production (p<0.05). The second experiment was designed to investigate effects of combination of one of halogenated compounds and either organic acids or fatty acids on methane production. Lower concentration of methane and lower A:P ratio were observed with PMDI compared with BES (p<0.01). In general medium pH, VFA, total gas and hydrogen production, and dry matter degradability were affected by addition of the same compounds. In addition, PMDI+malate treatment resulted in the highest molar proportion of propionate, and lowest A:P ratio and methane production (p<0.01). Hydrogen production was highest in PMDI+linolenic acid and lowest in BES+malate treatment (p<0.01). PMDI+malate combination was the most recommendable in reducing methane production without too much influence on digestibility under conditions of present studies.

• KSBB Journal
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• 제20권6호
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• pp.447-452
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• 2005

본 연구에서는 과일 폐액으로부터 고정화 세포를 이용하여 수소생산을 위한 배양조건을 조사하였다. 각종 과일 폐액 중에 수박 폐액에서 환원당의 함량이 가장 높았으며, 수소생산량은 2319.2 mL/L이었다. 고정화 물질 sodium alginate의 농도와 크기에 따른 수소생산성 효과는 검토범위 내에서는 적었다. 고정화된 비드의 내부 관찰에서 세포가 왕성하게 생육하고 있음을 확인했다. 대사의 효소물질로 이용될 수 있는 각종 아미노산의 첨가는 종류에 관계없이 수소생산성에 영향을 거의 미치지 않았다. 금속이온 $FeSO_4$를 첨가한 결과 최적 농도는 1.2 g/L이고, 1.3배의 수소생산 증가를 나타났다. 수소생산정지 후 배양액의 유기산은 lactic acid와 butyic acid가 가장 많았다.