• Food Science and Biotechnology
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• v.14 no.5
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• pp.561-565
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• 2005

In this study, we attempted to assess the effects of lactate and com steep liquor (CSL) on the production of bacterial cellulose (BC) by Gluconacetobacter persimmonis $KJ145^T$. The optimal condition for the production of BC was a lactate concentration of 1% (w/v) and a CSL concentration of 10% (w/v). Under these optimal conditions, 6 days of fermentation produced 6.90 g/L of BC. Both the BC production yield and cell growth increased continuously until the 20th day of fermentation, by which time 17.0 g/L had been produced. In a static culture trial, in which plastic containers were used as fermentation chambers for 6 days of fermentation, the BC production yield in the group initially cultured with 500 mL medium was higher than that of the 750 and 1000 mL media. In addition, the texture of the BC was examined according to its post-treatment in order to determine conditions for optimal textural characteristics. The strength, hardness, and other characteristics of the BC were negatively correlated with sucrose concentration, but were largely positively correlated with NaCl concentration. With regards to the effect of pH on textural change, BC strength and hardness were elevated at pH 2 and 8 but reduced at pH 4 and 6, indicating that the texture of the BC is extremely sensitive to treatment conditions.

• Food Science and Preservation
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• v.18 no.6
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• pp.875-883
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• 2011

Brown rice vinegar was made from brown rice mash with different brewing starter addition rates in static culture, and its quality characteristics were investigated. As a result, the amounts of alcohol produced in the fermentation process were shown to be 9.1, 8.8, 8.6 and 8.5% in the Nuruk 75 : crude enzyme 25 (B), Nuruk 50 : crude enzyme 50 (C), Nuruk 25 : crude enzyme 75 (D) and Nuruk 0 : crude enzyme 100 (E), respectively. The higher the percentage of crude enzyme added was, the lower the alcohol content that was produced. Nuruk 100 : crude enzyme 0 (A) was appeared to contain the lowest alcohol content (7.7%). In addition, the titratable acidity in all the groups was about 0.7%. The final titratable acidity (BV) of brown rice vinegar made with static culture was the highest (approximately 5.2%). The initial pH appeared to be between 3.6~4.0 and steadily decreased as the fermentation progressed, and the pH was almost unchanged after 15 day fermentation. The examination of the changes in the organic acids showed that the acetic acid content was similar in all the groups, and that the single starter added (AV, EV) group had much more other organic acids than the mixed starters added (BV, CV, DV) group. From these results, the mixed starters (Nuruk and crude enzyme) added group appeared to be superior to the single starter added in terms of alcohol production ability and vinegar quality. As the future aging process, however, is expected to change the flavor components and sensory characteristics, studies on various quality factors of vinegar are needed.

• Food Science and Preservation
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• v.18 no.5
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• pp.803-810
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• 2011

This study was performed to evaluate the quality of the commercial brown-rice vinegars of South Korean and Japanese origins, which were prepared via static acetic-acid fermentation. The major free amino acids of Korean brown-rice vinegars were proline, glutamic acid and phenylalanine, while those of the Japanese were proline, valine, phenylalanine, lysine, ${\gamma}$-aminobutyric acid, alanine and isoleucine. The ${\gamma}$-aminobutyric acid (GABA) and total amino acids (3686.37~4212.27 mg%) contents were found to be significantly higher in the Japanese than in the Korean brown-rice vinegars. The key volatile compounds of the Korean brown-rice vinegars, analyzed with GC-MS, were acetic acid, benzaldehyde, phenethyl alcohol and phenethyl acetate while those of the Japanese brown-rice vinegars were acetic acid, ethyl acetate, ethyl alcohol, isoamyl acetate, phenethyl acetate and benzaldehyde. The volatile patterns of the Korean and Japanese commercial brown-rice vinegars were effectively distinguished from each other using an electronic nose, through which it was also elucidated that the volatiles profiles were similar among the Japanese vinegars but were different among the Korean vinegars.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.350-351
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• 2000

We isolated cellulose-producing bacteria from persimmon vinegar(Korea traditional fermentation food). Some of these strains were selected for cellulose production in agitation culture. On the other hand, it was also found that strains suitable for static culture production were not necessarily suitable for agitation culture. Therefore we estimated the cellulose production of these isolates in static culture. To determine nutritional requirement for the production of bacterial cellulose, several nutrients as carbon source, nitrogen and mineral salt were tested.

• Food Science and Preservation
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• v.19 no.2
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• pp.301-307
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• 2012

The quality of brown rice vinegar that was produced via static culture (A) was compared with the quality of three types of domestic commercial brown rice vinegar (B, C, and D) and of three types of Japanese brown rice vinegar (E, F, and G). The results showed titratable acidity levels of 6.39%, 4.52-6.32%, and 4.51-4.89% in the static-cultured brown rice vinegar, the domestic commercial brown rice vinegars, and the Japanese brown rice vinegars, respectively. The pH levels were 3.28, 2.58-2.97, and 3.03-3.27 in the static-culture brown rice vinegar, the domestic commercial brown rice vinegars, and the Japanese brown rice vinegars, respectively, which show similar values of the static-culture brown rice vinegar and the Japanese brown rice vinegars. The total nitrogen (TN) values of the static-culture brown rice vinegar, the domestic commercial brown rice vinegars, and the Japanese brown rice vinegars were 0.24, 0.03-0.16, and 0.12-0.17, respectively, with the highest value for the static-culture brown rice vinegar, substantial differences among the domestic commercial brown rice vinegars, and similar contents among the Japanese brown rice vinegars. For free sugar, glucose was either detected only in a small quantity or not detected at all in the static-culture brown rice vinegar and the Japanese brown rice vinegars, which showed perfect fermentation. The glucose and maltose contents were higher in the domestic commercial brown rice vinegars. The organic acid content of the static-culture brown rice vinegar was similar to that of the Japanese brown rice vinegars. Therefore, the total acidity content, TN value, sensory property, and quality of the static-culture brown rice vinegar (A) were superior to those of the domestic and Japanese brown rice vinegars.

• Korean Journal of Food Science and Technology
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• v.45 no.2
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• pp.252-256
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• 2013

We tested the possibility of utilizing Korea domestic wheat (winter wheat variety "keumkangmil") as a source of vinegar production. After saccharification of the whole-wheat flour with wheat malt, the saccharized liquid undergoes alcoholic fermentation, followed by acetic fermentation. Acetic acid bacterium A8, which showed the highest acetic acid production (4.56%) with domestic wheat as substrate, was selected from conventional vinegars. The strain A8 was identified as Acetobacter pasteurianus A8 through phylogenetic study using 16S rDNA sequencing analysis. The optimal condition for the malt enzyme was found to be $15^{\circ}C$ for germination periods of 6 days; its amylase activity was 608.4 U. Acetic acid production from domestic wheat substrate supplemented with 5% ethyl alcohol reached 5.8% after 24 days of static fermentation at $30^{\circ}C$ with a seeding rate of 5%.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.254-264
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• 2010

To obtain an efficient natural lignocellulolytic complex enzyme, we screened an efficient lignocellulose-degrading composite microbial system (XDC-2) from composted agricultural and animal wastes amended soil following a long-term directed acclimation. Not only could the XDC-2 degrade natural lignocelluloses, but it could also secrete extracellular xylanase efficiently in liquid culture under static conditions at room temperature. The XDC-2 degraded rice straw by 60.3% after fermentation for 15 days. Hemicelluloses were decomposed effectively, whereas the extracellular xylanase activity was dominant with an activity of 8.357 U/ml on day 6 of the fermentation period. The extracellular crude enzyme noticeably hydrolyzed natural lignocelluloses. The optimum temperature and pH for the xylanase activity were $40^{\circ}C$ and 6.0. However, the xylanase was activated in a wide pH range of 3.0-10.0, and retained more than 80% of its activity at $25-35^{\circ}C$ and pH 5.0-8.0 after three days of incubation in liquid culture under static conditions. PCR-DGGE analysis of successive subcultures indicated that the XDC-2 was structurally stable over long-term restricted and directed cultivation. Analysis of the 168 rRNA gene clone library showed that the XDC-2 was mainly composed of mesophilic bacteria related to the genera Clostridium, Bacteroides, Alcaligenes, Pseudomonas, etc. Our results offer a new approach to exploring efficient lignocellulolytic enzymes by constructing a high-performance composite microbial system with synergistic complex enzymes.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.161-167
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• 1998

Whey is by-product from natural cheese manufacturing process. For alcoholic fermentation, the initial lactose content and pH were adjusted to 4.5% and 4.2, respectively. Two strains of yeasts (Kluyveromyces marxianus, Saccharomyces cerevisiae) and seven strains of lactic acid bacteria (Lactobacillus brevis, Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus lactis, Leuconostoc cremoris, Lactococcus lactis and Streptococcus thermophilus) were examined for their alcohol production and sensory acceptability. Ethanol content in the whey fermented by lactose-fermenting K. marxianus was 2.8% at 4th day of incubation and that fermented by nonlactose fermenting S. cerevisiae was 0.2%. In case of mixed fermentation with yeasts and tactic acid bacteria (LAB being inoculated at 0 hr), the maximum ethanol production was obtained in the sample inoculated at 16 hr by s. cerevisiae, and in the sample inoculated at 24 hr by K. marxianus. The optimum temperature was $37^{\circ}C$ for alcohol production under static condition. The production of $CO_2$ gas was higher in the whey fermented by K. marxianus (1.88%) than by S. cerevisiae (0.04%). The titratable acidity of the whey gradually increased with fermentation time and its content was 0.39% at 4th day of fermentation by K. marxianus and 0.52% by S. cerevisiae. Among seven strain of latic acid bacteria tested, Lactococcus lactis exerted synergistic effect for acid production with K. marxianus. Therefore, overall results suggestd that the combination of Lactococcus lactis and K. marxianus was best choice in fermenting cheese whey for edible purpose.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.469-472
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• 2002

Solid state fermentation was performed for the production of entomopathogenic fungus Metarhizium anisopliae HY-2 using wheat bran media containing rice bran. Fungal growth in a solid state fermentation system was estimated by viable cell count, spore count, and mycelial biomass. It was used chemical method measuring N-acetyl-glucosamine (chitin) content for estimating of mycelial biomass. In static flask culture, viable cell reached 2.40 ${\times}$ $10^8$ cfu/g at 23 days of culture at $27^{\circ}C$ and then mycelial biomass was 41.59 mg/g. Specific growth rate(${\mu}$ max) was 0.0418 $h^{-1}$ between 3 and 9 days when estimated by viable cell count and was 0.00976 $h^{-1}$ between 9 and 17 days when N-acetylglucosamine content was measured. Viable cells reached 1.12 ${\times}$ $10^8$ cfu/g in polypropylene-bag at 28 days of culture at $27^{\circ}C$. Formulated microbial pesticide containing M. anisopliae HY-2 were tested their bio-activity against Chestnut Brown Chafer (Adoretus tenuimaculatus). The protection rate of the liquid culture showed 13 ${\sim}$ 26 % with 1st to 3rd instar, and spore suspension of M. anisopliae HY-2 showed 56 ${\sim}$ 64%. Conidia produced by large scale solid-state fermentation showed 20 ${\sim}$ 27 % activity 60 ${\sim}$ 64 % with M. anisopliae HY-2.

• Journal of the Korean Wood Science and Technology
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• v.32 no.2
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• pp.1-8
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• 2004

Heavy metals were removed from CCA- and CCFZ- treated wood using a brown-rot fungi Tyromyces palustris. The amount of effective elements extracted from treated woods was compared for different treatment methods. The relationship between the amount of heavy metals removed and concentrations of oxalic acid for treated wood was examined. Also, the relationship between mycelia weight and removal rate was examined. The removed quantity of heavy metal from treated wood according to fermentation methods was examined. The extraction amount of chromium and arsenic components increased with increasing oxalic acid concentration, but the extraction amount of copper did not improved much. A 287 mg of mycelia weight can remove chromium and arsenic over 60% in 3 g CCA chips and copper was also removed over 50%. The chromium, copper and arsenic were removed over 60% by shaking fermentation, the removal rate of copper by static cultivation was higher than that of shaking fermentation. The removal rate of chromium, copper and arsenic were 72%, 61% and 59% with air-lift bioreactor, respectively.