• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.6-11
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• 1990

Hydrogen evolution from biomass-derived carbohydrates by some Clostridia and optimal culture conditions for hydrogen evolution were investigated. Among the organisms tested, Clostridium butyricum was efficient hydrogen producer with starch, xylan, pectin, cellobiose and xylose. In batch fermentation of Cl. butyricum, optimal conditions for hydrogen evolution were achieved at pH 7.0-8.5, 10-50 mM phosphate, and 2% (w/v) glucose. Total amount of molecular hydrogen evolved by the organism slightly increased at the presence of acetate (<150 mM) or butyrate (<20 mM) in the initial fermentation medium. Especially, in case of more than the above concentration of butyrate, growth and hydrogen evolution were dramatically inhibited. In the conditions were described here, 70 mmole of molecular hydrogen per mg of DCW was produced with 1%(w/v) glucose by the organism.

• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.329-337
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• 1985

A potent mold strain was selected to digest raw starch, which was classified as a strain of Rhizopus of zoe. Its amylase production was maximized when grown on wheatbran media for 3 days at 3$0^{\circ}C$ and initial pH 4. The crude enzyme was tested for ethanol fermentation by yeast, Saccharomyces cerevisiae IFO 7026, on various starchymaterials and the ethanol production after 4 days was: 9.4％ from rice powder, 9％ from corn powder, 8.1％ from sweet potato powder, and 5.4％ from potato powder, respectively.

• Journal of Microbiology and Biotechnology
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• v.24 no.12
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• pp.1664-1672
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• 2014

In this study, a fibrous bed bioreactor (FBB) was used for $\small{D}$-lactic acid ($\small{D}$-LA) production by Sporolactobacillus inulinus Y2-8. Corn flour hydrolyzed with ${\alpha}$-amylase and saccharifying enzyme was used as a cost-efficient and nutrient-rich substrate for $\small{D}$-LA production. A maximal starch conversion rate of 93.78% was obtained. The optimum pH for $\small{D}$-LA production was determined to be 6.5. Ammonia water was determined to be an ideal neutralizing agent, which improved the $\small{D}$-LA production and purification processes. Batch fermentation and fed-batch fermentation, with both free cells and immobilized cells, were compared to highlight the advantages of FBB fermentation. In batch mode, the $\small{D}$-LA production rate of FBB fermentation was 1.62 g/l/h, which was 37.29% higher than that of free-cell fermentation, and the $\small{D}$-LA optical purities of the two fermentation methods were above 99.00%. In fe$\small{D}$-batch mode, the maximum $\small{D}$-LA concentration attained by FBB fermentation was 218.8 g/l, which was 37.67% higher than that of free-cell fermentation. Repeate$\small{D}$-batch fermentation was performed to determine the long-term performance of the FBB system, and the data indicated that the average $\small{D}$-LA production rate was 1.62 g/l/h and the average yield was 0.98 g/g. Thus, hydrolyzed corn flour fermented by S. inulinus Y2-8 in a FBB may be used for improving $\small{D}$-LA fermentation by using ammonia water as the neutralizing agent.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.196-203
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• 2002

Effect of different levels (0 ,0.05, 0.15, 0.25%) of xanthan gum on kakdugi fermentation was investigated by analyzing physicochemical and sensory characteristics during fermentation at 2$0^{\circ}C$. During fermentation, pH was maintained higher, and total acidity and number of lactic acid bacteria, maintained lower in xanthan gum groups, especially in 0.05% addition group than control. Free sugar amount were higher in xanthan gun groups than control, and glucose and fructose which were the major free sugars, decreased rapidly during fermentation, whereas mannitol increased in all samples, especially in xanthan gum groups. Liquid content of kakdugi was smaller in 0.05% xanthan gum group than control. Viscosity of kakdugi liquid decreased rapidly whereas initial viscosity was maintained in xanthan gum groups. Hardness decreased during fermentation, but at the 7th day of fermentation was higher in 0.05% xanthan gum group than control. The result of sensory evaluation shows that there were no significant difference in sour odor, moldy, sour taste and savory taste among samples. Starch taste was higher in 0.15% or 0.25% xanthan gum, but there is no difference in 0.05% group, compared to control. Overall preference until the 5th day of fermentation, xanthan gum group was not significantly different from that of control but at the 7th day of fermentation, 0.05% addition group was significantly higher than control.

• Food Science and Preservation
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• v.14 no.5
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• pp.557-563
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• 2007

This study was investigated quality characteristics of alcohol fermentation broths and by-produce produced from 4 type of brown rice varieties. The result showed that Daeanbyeo(A), Baekjinju(B) and Sulkyeong(C) produced the high alcohol content(9.5, 9.7 and 9.8%) by non-steamed alcohol fermentation period whereas the Goami(D) gave poor content(3.5%). In addition, the effect of total free sugar content were examined for non-steamed alcohol fermentation period. Among these 4 type, 244.2 mg% showed the highest contents in the Goami(D). The steamed alcohol fermentation showed higher sugar content in overall with slight difference between the various brown rice. The total dietary fiber content variation according to the alcohol fermentation methods in non-steamed and steamed periods came up with the highest content in the Sulkyeong(C) fellowed by Baekjinju(B), Daeanbyeo(A), and Goami(D). The total free amino acid content by alcohol fermentation methods timed out to show the highest content in non-steamed Goami by-product followed by Goami powder steamed Goami by-product Although, the above result revealed the lowest alcohol fermentation efficiency in non-steamed Goami, but it had the highest by-product utilizing capacity. Therefore, Goami(D) was the lowest alcohol yield in alcohol fermentation treated with non-steam among groups, but Goami by-products of the Goami had the various nutritional constitutes including starch, dietary fibers and free amino acids, which can be suggested to be used as various functional food ingredient.

• Korean Journal of Food Science and Technology
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• v.47 no.6
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• pp.797-800
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• 2015

The effect of raw wheat flour on starch retrogradation retardation was investigated in a rice starch paste model. Specifically, in terms of amylase activity present in the wheat flour, the retardation effect was investigated depending on reaction temperature (40, 60, and $80^{\circ}C$), incubation time (0, 20, 40, and 60 min), and wheat flour addition levels (0-10%). An increase in wheat flour concentration resulted in a rapid decrease in the elastic modulus (G') as the incubation time increased. The G' changes of the rice starch pastes were furthermore fitted by the first order reaction for the reaction rate estimation on the temperature basis. The experimental reaction rate of the paste sample incubated with 10% wheat flour at $40^{\circ}C$ exhibited good agreement with the predicted value. This result implied that the first order reaction kinetics could be suitable to predict the changes in the G' as a function of incubation temperature and wheat flour concentration.

• Microbiology and Biotechnology Letters
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• v.42 no.4
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• pp.407-412
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• 2014

A number of Saccharomycopsis fibuligera strains that can hydrolyse and utilize starch as a carbon source were isolated from nuruk, a traditional Korean starter for rice wine fermentation, and their specific growth rates on starch-containing medium were compared to choose the prominent strain. S. fibuligera strain MBY1320 showed a higher growth rate at $42^{\circ}C$ than that of strain S. fibuligera KCTC7806, indicating that S. fibuligera MBY1320 has more thermo-tolerant machinery for starch hydrolysis and utilization than KCTC7806. Although the activity of ${\alpha}$-amylase at $30^{\circ}C$ was significantly lower for S. fibuligera MBY1320 than KCTC7806 (3,812.5 U vs. 14,878.5 U), S. fibuligera MBY1320 showed a much higher glucoamylase activity at $42^{\circ}C$ than S. fibuligera KCTC7806 (5,048.9 U vs. 13,152.3 U). Thus, a new S. fibuligera strain, with a higher starch-hydrolysing activity at elevated temperatures than that of other types of strain, this study reports.

• Korean Journal of Food Science and Technology
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• v.19 no.4
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• pp.371-376
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• 1987

The structral properties of rice starch and its components were investigated. The intrinsic viscosities of rice starch, amylose and amylopectin solutions were 1.053, 1.772 and 1.596 ml/g, respectively. ${\beta}-amlolysis$ limits of rice starch was 73% and those of amylose and amylopectin were 106 and 56%, respectively. The outer chain length $({\overline{OCL}})$ and inner chain length $({\overline{ICL}})$ of amylopectin were 1.56 and 7.7, respectivety. Debranching of rice starch with pullulanase yield two peaks on Sephadex G-75. The peak I at void volume was principally amylose components and peak II at ${\overline{dp}}$ 25-10, constituted of branched amylopectin. However, the elution profile of debranched amylopectin by pullulanase revealed a bimodal peak distribution at ${\overline{dp}}$ 35-25 hydrolyers and ${\overline{dp}}$ 25-10, and no distinct peak at void volume. The elution profile of the debranched, ${\beta}-amylase$ hydrolyrates of starch and amylopectin yielded major peak at ${\overline{dp}}$ 2-10.

• Journal of Microbiology and Biotechnology
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• v.19 no.5
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• pp.468-473
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• 2009

The antibiotic meroparamycin was produced in the free culture system of Streptomyces sp. strain MAR01. Five solid substrates (rice, wheat bran, Quaker, bread, and ground corn) were screened for their ability to support meroparamycin production in solid-state fermentation. In batch culture, wheat bran recorded the highest antibacterial activity with the lowest residual substrate values. The highest residual substrate values were recorded for both ground corn and Quaker. On the other hand, no antibacterial activity was detected for rice as a solid substrate. The use of the original strength of starch-nitrate medium in the solid-state fermentation gave a lower antibacterial activity compared with the free culture system. Doubling the strength of this medium resulted in the increase in the activity to be equivalent to the free culture. The initial pH (7.0) of the culture medium and 2 ml of spore suspension (1 ml contains $5{\times}10^{9}spores/ml$) were the optima for antibiotic production. The water was the best eluent for the extraction of the antibiotic from the solid-state culture. Ten min was enough time to extract the antibiotic using a mixer, whereas, 60 min was required when shaking was applied. Semicontinuous production of meroparamycin using a percolation method demonstrated a more or less constant antibacterial activity over 4 runs ($450-480{\mu}g/ml$). The semicontinuous production of the antibiotic was monitored in a fixed-bed bioreactor and the maximum activity was attained after the fourth run ($510{\mu}g/ml$) and the overall process continued for 85 days.

• Korean Journal of Food Science and Technology
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• v.24 no.5
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• pp.477-481
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• 1992

As a series of fundamental research projects to produce doenjang (Korean fermented soy paste) of better quality, two kinds of doenjang were manufactured from a traditional meju (Korean soy bean koji) and the mixed with Aspergillus oryzae and Bacillus natto, and histological changes in the cell structures of soy bean of the two were reported doenjang samples were observed and compared during the entire period of fermentation processes. Cell walls of the soy bean were ruptured by pressure and heat during the pressure cooking process and some of them were observed to have the ghost-like shapes. Remarkable differences in the plasmolysis of the cytoplasms were observed between the seed coat and the inner part of soy bean. Small vacuoles resulting from the fusion of the glycoprotein globules by protease and from the hydrolysis of the starch granules by amylase were also observed. Penetration of microorganisms was transferred from the seed coat to the inside of soy bean as the fermentation proceeded. Slimy substances were observed on the seed coat and the parenchyma cells of soy bean fermented with the mixed with Aspergillus oryzae and Bacillus natto. Cell walls of soy bean became difficult to stain and they showed unusual, polygonal shapes as the fermentation proceeded. Samples fermented with the mixed with Aspergillus oryzae and Bacillus natto showed more remarkable tendencies than traditional meju.