• KSBB Journal
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• v.27 no.6
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• pp.352-360
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• 2012

Bacillus clausii I-52 which produced SDS- and $H_2O_2$-tolerant extracellular alkaline protease (BCAP) was isolated from heavily polluted tidal mud flat of West Sea in Incheon, Korea and stable strain (transformant C5) of B. clausii I-52 harboring another copy of BCAP gene in the chromosome was developed using the chromosome integration vector, pHPS9-fuBCAP. When investigated the production of BCAP using B. clausii transformant C5 through pilot-scale submerged fermentation (500 L) at $37^{\circ}C$ for 30 h with an aeration rate of 1 vvm and agitation rate of 250 rpm, protease yield of approximately 105,700 U/mL was achieved using an optimized medium (soybean meal 2%, wheat flour 1%, sodium citrate 0.5%, $K_2HPO_4$ 0.4%, $Na_2HPO_4$ 0.1%, NaCl 0.4%, $MgSO_4{\cdot}7H_2O$ 0.01%, $FeSO_4{\cdot}7H_2O$ 0.05%, liquid maltose 2.5%, $Na_2CO_3$ 0.6%). The enzyme stability of BCAP was increased by addition of polyols (10%, v/v) and also, the stabilities of BCAP towards not only the thermal-induced inactivation at $50^{\circ}C$ but also the SDS and $H_2O_2$-induced inactivation at $50^{\circ}C$ were enhanced. Among the polyols examined, the best result was obtained with propylene glycol (10%, v/v). The BCAP supplemented with propylene glycol exhibited extreme stability against not only the detergent components such as ${\alpha}$-orephin sulfonate (AOS) and zeolite but also the commercial detergent preparations. The granulized enzyme of BCAP was prepared with approximately 1,310,000 U/g of granule. Wash performance analysis using EMPA test fabrics revealed that BCAP granule exhibited high efficiency for removal of protein stains in the presence of anionic surfactants as well as bleaching agents. When compared to Savinase 6T$^{(R)}$ and Everlase 6T$^{(R)}$ manufactured by Novozymes, BCAP under this study probably showed similar or higher efficiency for the removal of protein stains. These results suggest that the alkaline protease produced from B. clausii transformant C5 showing high stability against detergents and high wash performance has significant potential and a promising candidate for use as a detergent additive.

• Microbiology and Biotechnology Letters
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• v.43 no.1
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• pp.56-64
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• 2015

It has been known for some time to the wine industry that non-Saccharomyces yeasts play an important role in increasing volatile components through the secretion of extracellular enzymes. The objective of this study was to investigate what types of enzymes are produced by 1,007 non-Saccharomyces yeast strains isolated from Korean fermented foods. Among 1,007 yeast strains, the 566, 45 and 401 strains displayed β-glucosidase, glucanase and protease activity, respectively. In addition, the 563 and 610 strains possessed tolerances against cerulenin and TFL, and the 307 strain was tolerant to 15% ethanol. Yeasts producing harmful biogenic amines and hydrogen sulfide were excluded from further study, and eventually 12 yeast strains belonging to the genera Wickerhamomyces, Hanseniaspora, Pichia, Saccharomyces were identified, based on the 26S rRNA gene sequences. Among the 12 strains, the 9 and 5 strains possessed glucose and ethanol tolerance, respectively. Yeasts belonging to the genus Saccharomyces produced more than 8% alcohol, but non-Saccharomyces yeasts produced only 3% alcohol.

• Journal of Life Science
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• v.24 no.4
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• pp.411-418
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• 2014

This study was to investigate the potential effects of fermented Angelica gigas Nakai (FAG) at 5% (w/w) levels in Sprague-Dawley strain rats, which were intoxicated with 1% (w/w) orotic acid (OA) for 10 days. The activities of several hepatic enzymes, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), and cholinesterase were increased when OA was treated, but these parameters were significantly decreased by FAG administration. OA treatment induced a significant increase in the thiobarbituric acid reactive substances (TBARS) levels, which was attenuated by FAG administration. Liver nonheme ion was decreased in the OA treatment group and was significantly increased in FAG administration, which suggests that lipid peroxidation contents are inversely correlated with liver nonheme ion content. The glutathione concentration was significantly decreased in the OA treatment group compared with the normal group, but this concentration was significantly increased in the FAG group, and it showed the antioxidant ability of glutathione. Based on these results, fermented Angelica gigas Nakai is a material with significant potential for development into a health food that can improve fatty liver conditions.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1135-1142
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• 2003

The purification and characteristics of the biosynthesis enzyme of vitamin C from microorganisms related with kimchi fermentation were investigated to define vitamin C biosynthetic pathways in yeast. A yeast strain (Pichia onychis 16-4) which synthesizes vitamin C with galacturonic acid as substrate at high rate was isolated from kimchi. The enzyme $L-galactono-{\gamma}-lactone$ oxidase isolated from the yeast was purified and characterized. The specific activity of the crude enzyme was 7.26 unit/mg protein, which increased to 4,698 unit/mg protein with a chromatography of Sephacryl S-200HR; indicating a 647.1-fold level of purification. The molecular weights of the dissociated enzymes were estimated to be 31,000, 39,000, and 50,000 KD. Among the substrates tested, $L-galactono-{\gamma}-lactone$ was the most effective. The enzyme showed optimum activity ah pH 7.8 and 35c. The purified enzyme uses $O_2$ as the electron acceptor for oxidation of $L-galactono-{\gamma}-lactone$.

• Food Science of Animal Resources
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• v.25 no.3
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• pp.357-364
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• 2005

To search probiotic microorganisms, we isolated Lactobacillus sp. from kefir, The Lactobacillus sp. strain showed $99.5\%$ of identity to species Lactobacillus rhamnosus by API kit. Lactobacillus rhamnosus showed high resistances to acidic environment, which grew well even at pH 2.0 and $1.0\%$ bile salt Enzyme activity of Lactobacillus rhamnosus was higher in amylase ($0.673\;{\mu}mol/min/mg$) than that in xylanase ($0.288\;{\mu}mol/min/mg$), cellulase($0.117\;{\mu}mol/min/mg$) and phytase($0.269\;{\mu}mol/min/mg$). Especially, the Lactobacillus rhamnosus showed high heat stability which remained $1{\times}10^6\;CFU/ml$ at $60^{\circ}C$. The maximum numbers of Lactobacillus rhamnosus on growth owe was reached at 24 h fermentation and pH was decreased to 4.6. The resistances of Lactobacillus rhamnosus to acidic pH and bile salt were better than that of Lactobacillus acidophilus used as control. When Lactobacillus rhamnosus was cultured with E. coli in MRS broth, E. coli was disappeared after 18 h. These result suggest that the isolated Lactobacillus rhamnosus has a useful probiotics properties.

• Food Science of Animal Resources
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• v.28 no.2
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• pp.204-210
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• 2008

A total of 70 colonies were isolated from the Korean human milk samples on the BCP plate count agar. These LAB isolates were subcultured in 10% reconstituted skim milk, and two strain thereof were finally selected for their highest acid productions. These strains were identified as Enterococcusfaecium based on 16S rDNA sequencing data, named as Enterococcus faecium KHM-11. Sugar utilization of E. faecium KHM-11 was investigated by API 50CH kit, and 19 different sugars including D-arabinose, L-arabinose, galactose, D-glucose, D-fructose, and D-mannose were utilized. For fermentation profiles, a yogurt inoculated by E. faecium KHM-11 after 15 hour, reached at pH 4.09, titratable acidity at 1.10% and average viable counts $1.30{\times}10^9\;CFU/mL$. Effects of the administration of yogurt 0.5% of piglet diet to piglets were investigated for growth rate, analysis of blood and incidence of diarrhea. 24 heads of piglets were divided into two groups: the experimental and the control of 12 animals each. The average growth rate in the yogurt-fed group was higher for 21.67%, compared with control (p<0.05). There were no differences in the concentrations of blood glucose, cholesterol, albumin and globulin between the two treatments. Incidence of diarrhea was no in pigs fed yogurt as compare to control.

• Korean Journal of Microbiology
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• v.37 no.2
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• pp.170-175
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• 2001

In order to produce xylitol with high yield, experiments were carried out to develope xylitol dehydrogenase(XDH) defective mutant from P. stipitis and to investigate the xylitol fermentation characteristics of mutant strain. After treatment of P. stipitis with EMS, mutant PXM-4 was selected based on te XDH activity and xylitol production capability. Among the tested cosubstrates, galactose was selected as an adequate cosub-strate on xylitol production of mutant PXM-4. But with the increase in the concentration of galactose in the medium, xylitol production was decreased because the transport of xylose into cell was inhibited by galactose. The optimal concentration of galactose for the production of xylitol using 20 g/ι xylose was 20 g/ι Under this condition, maximum concentration of xylitol and yield were 14.4 g/ι and 97%, respectively. In order to prevent the inhibitory effect of xylose transport by galactose, galactose was fed with low concentration and the concentration of xylitol produced was increased up to 25 g/ι.

• Korean Journal of Microbiology
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• v.36 no.1
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• pp.33-39
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• 2000

Some of thermophilic fungi which has growth-promoting effect on Pleurotus ostreatus were isolated from compost during high temperature fermentation process. The temperature optima of 7 isolated thermophilic fungi were $50^{\circ}C$ on PDA media. Isolated strains S-1 and S-2 have the best mycelial growing rate, so these isolates were expected as excellent thermophilic fungi for high temperature composting and mycelial growing of oyster mushroom. In liquid culture, the optimal pH of thermophilic fungi observed variously, pH 7.0-10.0 but most of thermophilic fungi grow well in pH 8.0-pH 9.0 and the final pH of media after cultured was done pH 5.5-6.0. In liquid culture of thermophilic fungi on the optimal condition, S-2 have the best mycelial growing rate. The growing rate of thermophilic fungi S-1, S-2, S-5, and S-10 on lignocellulosic substrates was good but Humicola grisea var. thermoidea, well know thermophilic fungi which has growth-promoting effect on Agaricus bisporus, was poor and which was well grown on PDA at $50^{\circ}C$, pH 7.0. Isolated strain S-1 was identified as Trichophyton sp. and other 6 strains were identified as Sepedonium sp. by morphological characteristics.

• Journal of Animal Science and Technology
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• v.48 no.2
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• pp.307-314
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• 2006

To search direct fed microbials, we isolated a Candida sp. from kefir grain. The isolated Candida sp. strain showed 99.8% of identity to the species of Candida kefyr by API 20C kit. Enzyme activity of Candida kefyr was higher in amylase (0.33±1.12μmol/min/mg) than that in phytase (0.052±0.98μmol/ min/mg) cellulase(0.051±μmol/min/mg) and xylanase (0.011±0.98mol/min/mg). The maximum numbers of Candida kefyr in growth curve were reached at 30 h fermentation. Candida kefyr showed high resistances to acidic environment, which was not perfectly extincted even at pH 2.0. And it showed high tolerance to bile salt which had almost 97.2% of survival in the presence of 1.0% bile salt.Especially, Candida kefyr showed high heat stability which remained 10% of initial microorganisms at 60℃. Candida kefyr was not generally inhibited by most of 11 antibiotic agent which contained tetracycline groups. These results suggest that the isolated Candida kefyr has a useful properties as probiotics.

• Food Science of Animal Resources
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• v.28 no.5
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• pp.587-595
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• 2008

In order to develop a new starter for fermented milk, 1037 bacterial strains were isolated from raw milk. The strain that showed excellent acid producing and angiotensin converting enzyme (ACE) inhibitory activity (88.6%) was selected and identified as a Lactobacillus zeae based on the result of API carbohydrate fermentation pattern and 16S rDNA sequence. Lactobacillus zeae RMK354 was investigated further to study its physiological characteristics. It showed strong ACE inhibitory activity compared with commercial LAB starters tested. The optimum growth temperature of L. zeae RMK354 was $40^{\circ}C$ and it took 10 hr to reach pH 4.3 under this condition. L. zeae RMK354 showed more sensitive to penicillin-G, bacitracin, novobiocin, in a comparison of 14 different antibiotics, and showed most resistance to polymyxin B and vancomycin. It showed higher esterase and leucine arylamidase activities compared with 16 other enzymes. It was comparatively tolerant to bile juice and able to survive at pH 2 for 3 hr. It showed inhibitory activity against Salmonella Typhimurium with the rate of 60%. Based on these and previous results, L. zeae RMK354 could be an excellent starter culture for fermented milk with high level of ACE inhibitory activity.