• 한국식생활문화학회지
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• 제21권4호
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• pp.420-425
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• 2006

This study was conducted to produce vinegar using maesil. Acetic acid bacteria was 20 strains isolated from several conventional vinegars. Among the isolates, a strain showed highest acetic acid productivity was selected and identified as Acetobacter sp. SK-7. The optimum medium of acetic acid production by Acetobacter sp. SK-7 was 30% of maesil juice, 4% of ethanol, and 2% of starting acidity and 0.2% of glucose. Optomum condition for the high yield of acetic acid was in the shaking culture at 30$^{\cire}$. The acidity of culture medium was reached to 7.1% after 12 days fermentation. Organic acid was identify 6 kinds containing acetic acid. The total content was 7,068.7 mg% after 12 days and malic acid slowly decreased and acetaic and citirc acid gradationally increased according to fermentation

• 한국미생물·생명공학회지
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• 제23권1호
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• pp.12-16
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• 1995

Medium components for lactic acid production were optimized with a strain of Lactobacillus sp., isolated by our Lab. Nitrogen source was the key component and manganese ion was also important for lactic acid production in this strain. Optimal concentration of manganese ion was 0.03 g/l as MnSO$_{4}$ 4 - 5 H$_{2}$O base. Other mineral elements, however, had little effect on it. Among the nitrogen sources we examined, yeast extract showed the highest productivity. Yeast extract, the exellent but very expensive medium component, could be partially replaced by soytone until 60% dry base with higher productivity, or by tryptone enforced with vitamines and nucleic acids. In order to replace yeast extract completely, we examined several inexpensive nitrogen sources and their enzymatic hydrolyzates. The hydrolyzate of vital wheat gluten was the best of them.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권3호
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• pp.251-257
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• 2006

The components of the media used to elicit the biosynthesis of $poly-{\gamma}-glutamic$ acid $({\gamma}-PGA)$ by Bacillus subtilis ZJU-7 were investigated, particularly the carbon and nitrogen sources Of the 7 carbon sources investigated, sucrose induced the highest rate of ${\gamma}-PGA$ productivity; among the nitrogen sources, tryptone had the best effect for ${\gamma}-PGA$ production. A $2^{6-2}$ fractional factorial design was used to screen factors that influence ${\gamma}-PGA$ production significantly, and a central composite design was finally adopted to formulate the optimal medium. ${\gamma}-PGA$ productivity improved approximately 2-fold when the optimal medium was used compared with the original nonoptimized medium, and volumetric productivity reached a maximum of 58.2 g/L after a 24-h cultivation period.

• Biotechnology and Bioprocess Engineering:BBE
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• 제2권2호
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• pp.69-72
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• 1997

The pH of microbial culture medium was calculated from equations of equilibrium, meterial balances for ionic components and electro-neutrality theory. Ammonium ion consumption and Acetic acid production are found out to be the major contributors for the alteration of the pH as well as the buffer capacity of the medium. By measuring the buffer capacity on-line, levels of acetic acid were estimated by a software sensor using pH signal in a fermentation process of E.coli growing in a minimal medium. The measured values of acetic acid showed good correlation to those of estimated by the software sensor.

• Journal of Plant Biology
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• 제9권1_2호
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• pp.1-6
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• 1966

Using the Chlorella cells which had been uniformly labeled with $^{32}P$, the distribution of phosphorus in various fractions of cell material was investigated. Uniformly $^{32}P$-labeled Chlorella cells were further grown in a P-free medium, and some protions of the cells were taken out at intervals during the culture, and subjected to analyze the contents of $^{32}P$ in various fractins of the cell constituents. 2. Analysis of the $^{32}P$-labeled Chlorella cells showed that the highest in P-content was the fraction of RNA followed by those of lipid, RNA-polyphosphate complex, acid-insoluble polyphosphate, acid-soluble polyphosphate, DNA and protein. 3. During the culture of $^{32}P$-labeled Chlorella cells in a P-free medium, amounts of phosphate in DNA, protein and lipid fractions increased, while the P-contents in the fraction of RNA-polyphosphate complex decreased as well as those of acid-insoluble polyphosphate and acid-soluble polyphosphate fractions. 4. It was inferred that phosphorus used in the syntheses of DNA and protein was taken from polyphosphates of the cells, and RNA-polyphosphate complex would play an important role as a phosphate pool.

• 한국미생물·생명공학회지
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• 제40권4호
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• pp.424-429
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• 2012

The intention of this research was to investigate the solubilization of primary sewage sludge using lactic acid bacteria cultured in a glucose and yeast extract medium. Glucose as the carbon source and yeast extract as the source of nitrogen were chosen as an economic medium with the potential for the mass production of lactic acid bacteria. The optimal concentrations of the medium were 3% (w/v) glucose and 2% (w/v) yeast extract. In this study, in order to improve field applications for the solubilization of sludge at sewage treatment plants, a powdered form of lactic acid bacteria was produced. The optimal inoculum of the powder for the maximum efficiency of solubilization was 1% (w/v). In that condition, the SCOD value increased from 8600 (mg/L) at the beginning of experiment to 10290 (mg/L) at 96 h, with the highest solubilization rate (20.6% DDCOD) and 11.2% (SCOD). Also, the TVFAs of the lactic acid bacteria inoculation group were produced more than that of the control group. In particular, acetic acid was produced 5 times more in the experimental group than in the control group. In this research, the potential of lactic acid bacteria in the pretreatment of primary sewage sludge as a solubilizer, and as an energy source producer for microbial fuel cells was revealed.

• Preventive Nutrition and Food Science
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• 제9권2호
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• pp.113-120
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• 2004

Selected microbiological and biochemical characteristics of the steeping process for the production of yukwa, a traditional Korean oil-puffed snack made of waxy rice, were investigated during steeping of waxy rice in water for 15 days. The lengthy steeping process was largely predominated by lactic acid bacteria (LAB), particularly, Lactobacillus and Leuconostoc. The predominat type of bacterium isolated was the Y26 strain tentatively identified as Lactobacillus plantarum. The titratable acidity of the steeping medium increased from 0.01 to 1.13%, in parallel with the decrease in pH ranging from 6.3 to 4.2 as the steeping period increased from 0 to 15 days. A high amount of lactic acid and to a much lesser extent, butyric acid, acetic acid, propionic acid, and succinic acid were detected during the steeping process. The amount of reducing sugars in the steeping medium increased from 0.61 to 10.43 mg/mL, whereas sucrose decreased from 0.46 mg% to an undetectable level. Starch degradation products including glucose, maltose and oligosaccharides ranging G3-G7 were not initially noticed, but their content increased during the steeping process until completion. However, no oligosaccharides larger than G8 were detected in the steeping medium. The activities of $\alpha$-amylase, $\beta$-amylase and protease in the steeping medium of waxy rice tended to rise increase with time during the steeping process. From these results, the lengthy steeping process in yukwa production can be characterized as the spontaneous fermentation, dominated by lactic acid bacteria, which is a necessary process for inducing biochemical modification of waxy rice.

• Journal of Microbiology and Biotechnology
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• 제29권7호
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• pp.1061-1070
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• 2019

In the present study, the optimization of poly(${\gamma}$-glutamic acid) (${\gamma}$-PGA) production by Bacillus sp. FBL-2 was studied using a statistical approach. One-factor-at-a-time method was used to investigate the effect of carbon sources and nitrogen sources on ${\gamma}$-PGA production and was utilized to select the most significant nutrients affecting the yield of ${\gamma}$-PGA. After identifying effective nutrients, response surface methodology with central composite design (CCD) was used to obtain a mathematical model to identify the optimum concentrations of the key nutrients (sucrose, $\text\tiny{L}$-glutamic acid, yeast extract, and citric acid) for improvement of ${\gamma}$-PGA production. The optimum amount of significant medium components appeared to be sucrose 51.73 g/l, $\text\tiny{L}$-glutamic acid 105.30 g/l, yeast extract 13.25 g/l, and citric acid 10.04 g/l. The optimized medium was validated experimentally, and ${\gamma}$-PGA production increased significantly from 3.59 g/l (0.33 g/l/h) to 44.04 g/l (3.67 g/l/h) when strain FBL-2 was cultivated under the optimal medium developed by the statistical approach, as compared to non-optimized medium.

• Mycobiology
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• 제33권1호
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• pp.23-29
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• 2005

The effects of different concentrations of three amino acids as carbon and or nitrogen sources on mycelial dry weights, changes in pH values of synthetic medium, ammonia secretion and extracellular protease activity by three zoosporic fungi, pathogens of fish and shellfish, were studied. As compared with the control, the addition of isoleucine and aspartic acid as nitrogen sources were generally stimulative for mycelial dry weight production whereas phenylalanine was inhibitory irrespective to the tested fungal species. When amino acids served as carbon and nitrogen sources, the mycelial dry weights of the three fungi were increased (mostly non-significantly) relative to untreated control but weights were decreased as the concentrations of the three amino acids raised. The addition of individual amino acids as carbon and nitrogen sources to the medium significantly increased pH values of the medium comparable to the control. The addition of each of the three amino acids as carbon and nitrogen sources to the medium significantly induced ammonia secretion by the three species of zoosporic fungi. Ammonia secretion in synthetic medium amended with amino acids as nitrogen source raised by the three zoosporic fungi relative to untreated control except in case of Achlya racemosa treated with isoleucine. Extracellular protease activity was almost promoted in case of Achlya proliferoides and Saprolegnia furcata cultures treated with isoleucine and aspartic acid individually in presence of glucose and vice versa in case of phenylalanine. However, extracellular protease activity of A. racemosa decreased compared with the control at various concentrations of isoleucine and both phenylalanine and aspartic acid assumed inconsistent effects. Extracellular protease activity of the three zoosporic fungi in the medium devoid of glucose varied depending upon zoosporic fungal species, the tested amino acid and the applied concentrations. The values of protease activity were approximately less two folds than that obtained in presence of glucose.

• Journal of Plant Biotechnology
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• 제30권3호
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• pp.301-305
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• 2003

The effects of inorganic nitrogen sources such as KNO$_3$ and NH$_4$ NO$_3$ on cell growth and production of chlorogenic acid and eleutheroside E derivative were investigated in 5L bioreactor cultures of Eleutherococcus senticosus. The cell growth in the 1/2MS medium containing 15mMKNO$_{3}$. The fresh weight of cells harvested from bioreactor was affected by the concentration ratio of NO$_3$$^{[-10]}$ and NH$_4$$^{+}$ in culture medium. At the viewpoint of secondary metabolite production, the production of chlorogenic acid was affected by the concentration of NH$_4$$^{+}$ in the culture medium, but not by the total concentration of nitrogen sources in the culture medium. Futhermore, eleutheroside E derivative production was also affected by the concentration ratio of NO$_3$$^{[-10]}$ and NH$_4$$^{+}$ in the culture medium. Base on those results, it is suggested that cell growth and production of secondary metabolite(chlorogenic acid and eleutheroside E derivative) could be manipulated by controlling the total concentration of nitrogen sources and the concentration ratio of NO$_3$$^{[-10]}$ and NH$_4$$^{+}$ in the culture medium. medium.