• Journal of Microbiology and Biotechnology
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• v.8 no.5
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• pp.484-489
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• 1998

Galactooligosaccharides (GalOS) were efficiently produced by partially purified $\beta$-galactosidase from the yeast strain Bullera singularis ATCC 24193. Ammonium sulfate precipitation and ultrafiltration methods were used to prepare the enzyme. The enzyme activity decreased at $50^{\circ}C$ and above. A maximum yield of 40% (w/w) GalOS, corresponding to 120 g of GalOS per liter, was obtained from 300 g per liter of lactose solution at $45^{\circ}C$, pH 3.7 when the lactose conversion was 70%. The yield of GalOS did not increase with increasing initial lactose concentration but the total amounts of GalOS did. Volumetric productivity was 4.8 g of GalOS per liter per hour. During this reaction, the by-products, glucose and galactose, were found to inhibit GalOS formation. Reaction products were found to be comprised of disaccharides and trisaccharides according to TLC and HPLC analyses. We propose the structure of the major product, a trisaccharide, to be ο-$\beta$-D-galactopyranosyl-(l-4)-ο-$\beta$-D-galactopyranosyl-(l-4)-$\beta$-D-glucose (4'-galactosyl lactose).

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.312-316
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• 2004

Five strains, producing bacterial thermostable L-arabinose isomerase, were isolated from Korean soil samples obtained from compost under high temperature circumstances. Among these strains, the CBG-Al showed the highest L-arabinose isomerase activity at $60^\circ{C}$ and was selected as a D-tagatose producing strain from D-galactose. This strain was identified as Geobacillus thermodenitrificans based on the 16S rRNA analysis, and biological and biochemical characteristics. The isolated strain was aerobic, rod-shaped, Gram-positive, nonmotile, and an endospore-forming bacterium. No growth was detected in culture temperature below $40^\circ{C}$. The maximum growth temperature and maximum temperature of enzyme activity were $75^\circ{C}$ and $65^\circ{C}$, respectively. In metal ion effects, $Ca^{2+}$ was the most effective enzyme activator with the reaction rate by 150%. In a 5-1 jar fermentor with 3-1 MY medium, L-arabinose isomerase activity was growth-associated and pH decreased rapidly after the initial logarithmic phase.

• KSBB Journal
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• v.19 no.4
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• pp.295-300
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• 2004

A marine bacterium for producing an collagenolytic protease was isolated from the southern sea of Korea and identified as Vibrio vulnificus and named as Vibrio vulnificus CYK279H. This strain producing an collagenolytic protease was showed high activity toward collagen and gelatin as substrate. The optimum initial pH, NaCl, and temperature for cell growth and protease production was 7.5, 2.0% and 25$^{\circ}C$, respectively. Optimization for collagenolytic protease production was composed of 0.3% D-galactose, 0.6% yeast extract, 4.0% gelatin, 0.2% (NH$_4$)$_2$SO$_4$, and 0.2 mM ferric citrate in artificial sea water. The maximum protease production was required gelatin and yeast extract. The collagenolytic protease production by Vibrio vulnificus CYK279H reached a maximum of 73 unit/l after the cultivation for 18 h under the optimized medium.

• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.737-746
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• 2012

본 연구는 mushroom complete medium(MCM) 액체배지에 수삼 추출물(GE, $65^{\circ}Bx$)을 첨가하여 면역활성이 증진된 노루궁뎅이버섯(Hericium erinaceum) 균사체를 배양하고, 균사체로부터 활성다당성분을 분획하고자 하였다. MCM에 대하여 GE를 5, 10과 15%(v/v) 첨가한 액체배지에서 균사체를 배양하고, 각각의 조다당획분(HE-GE-5-CP, HE-GE-10-CP와 HE-GE-15-CP)으로 분획하여 면역활성을 측정한 결과, HE-GE-10-CP는 HE-GE-5-CP와 HE-GE-15-CP보다 높은 활성을 나타내었으며, GE를 첨가하지 않은 MCM에서 배양된 균사체 조다당획분(HE-CP)보다 유의적으로 증진된 면역활성을 나타내었다. 또한, HE-GE-10-CP의 DEAE-Sepharose CL-6B 분획물 중 가장 높은 활성을 나타낸 HE-GE-10-CP-II획분은 대조군인 HE-CP의 어떠한 획분보다도 유의적으로 높은 면역활성과 암 전이 억제활성을 나타내었다. 한편, 활성획분인 HE-GE-10-CP-II는 arabinose, rhamnose, galactose, glucose와 uronic acid(molar ratio; 0.34:0.26:0.99:1.00:0.39)로 구성되어 있으나, 대조군인 HE-CP의 동일용매 용출획분으로서 HE-GE-10-CP-II보다는 활성이 낮은 HE-CP-II는 fucose, mannose, galactose와 glucose(molar ratio; 0.32:0.55:1.00:0.96)를 함유하여 다른 구성당 분포를 나타내었다. 따라서 노루궁뎅이버섯 균사체 액체배양에서 수삼 추출물 첨가는 균사체의 구성당 변화를 통한 면역활성 증진에 관여하는 것으로 사료되어 기능성 소재 개발에 유용할 것으로 사료된다.

• The Korean Journal of Mycology
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• v.11 no.2
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• pp.91-95
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• 1983

To investigate antitumor constituents of Hydnum repandum, which belongs to edible basidiomycetes, the mycelia separated from the carpophore were shake-cultured and subjected to hot water extraction. The extract was concentrated under vacuum and mixed with a three-fold volume of 95% ethanol to yield precipitates. The water soluble fraction of the precipitates was dialyzed and then lyophilized to yield a water soluble protein-polysaccharide fraction (= WPPF). This exerted antitumor activity against sarcoma 180 implanted in ICR mice. When administered i.p. at the dose level of 20mg/kg once daily for ten consecutive days, it showed an inhibition ratio of 54.3%. WPPF was found to be composed of a polysaccharide moiety (42% of WPPF) and a protein moiety (28% of WPPF) when determined by colorimetric method using anthrone reagent and Folin's phenol reagent. The polysaccharide moiety of WPPF was found to contain glucose (57.4%), mannose(19.3%), galactose (10.8%), xylose (6.8%), and fucose (5.7%), when the methanolysate of WPPF was analysed by GLC method.

• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.1018-1021
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• 2010

Metallic and non-metallic isomerases can be used to produce commercially important monosaccharides. To determine which category of isomerase is more suitable as a template for directed evolution to improve enzymes for galactose isomerization, L-arabinose isomerase from Escherichia coli (ECAI; E.C. 5.3.1.4) and tagatose-6-phosphate isomerase from Staphylococcus aureus (SATI; E.C. 5.3.1.26) were chosen as models of a metallic and non-metallic isomerase, respectively. Random mutations were introduced into the genes encoding ECAI and SATI at the same rate, resulting in the generation of 515 mutants of each isomerase. The isomerization activity of each of the mutants toward a non-natural substrate (galactose) was then measured. With an average mutation rate of 0.2 mutations/kb, 47.5% of the mutated ECAIs showed an increase in activity compared with wild-type ECAI, and the remaining 52.5% showed a decrease in activity. Among the mutated SATIs, 58.6% showed an increase in activity, whereas 41.4% showed a decrease in activity. Mutant clones showing a significant change in relative activity were sequenced and specific increases in activity were measured. The maximum increase in activity achieved by mutation of ECAI was 130%, and that for SATI was 190%. Based on these results, the characteristics of the different isomerases are discussed in terms of their usefulness for directed evolution of non-natural substrate isomerization.

• Microbiology and Biotechnology Letters
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• v.17 no.1
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• pp.35-45
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• 1989

Streptococcus thermophilus 510 was investigated as n potential source of $\beta$-galactosidase. Optimum cultural conditions for maximum enzyme production were 0.5% loctose as carbon source, initial pH 7.0, 37 $^{\circ}C$, and 18 hours of cultivation. The enzyme was purified to homogeneity by ammonium sulfate fractionation, protamine sulfate precipitation, Sephadex G-200 gel filtration, and DEAE-Sephadex A-50 ion exchange chromntography. The purified enzyme exhibited an optimum pH at 1.0, and an optimum temperature of 5$0^{\circ}C$. Metal ions such as Mn$^{2+}$ and $K^+$, dithiothreitol, and 2-mercaptoethanol stimulated $\beta$-galactosidase activity. Ethylenediamine tetraacetic add, 8-hydroxyquinoline, Hg$^2+$, Zn$^{2+}$, Co$^{2+}$, $Ca^{2+}$, and galactose were inhibitory. The $K_m$ and V$_{max}$ for o-nitrophenyl $\beta$-D-galactopyranoside were 1.25mM and 88.50$\mu$moles/min.mg protein, respectively. The molecular weight was estimated to be 520,000, and the amino acid composition indicated relatively high contents of glutamic acid, aspartic acid, leucine, and valine.

• Analytical Science and Technology
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• v.5 no.4
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• pp.465-469
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• 1992

An analytical procedure is presented for the quantitative determination of lactose, glucose, and galactose in the hydrolyzate of lactose by ${\beta}$-galactosidase with high-performance liquid chromatography. An Aminex HPX-87C column at $85^{\circ}C$ and refractive index detector were used to resolve lactose, glucose, and galactose in only 12 minutes with distilled and deionized water as a mobile phase. The validity of high-performance liquid chromatography as a method for the assay of ${\beta}$-galactosidase was supported by recovery experiments and comparision of results with those by ONPG method, a spectrophotometric assay. The procedure was appropriate for determination of sugars in the enzyme reaction mixture and could by applied to analysis of ${\beta}$-galactosidase activity.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.122-127
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• 2001

This study was conducted to investigate the characteristics and biological activities of the substance extracted from the fruit body of Formitopsis rosea. The substance was extracted by hot water and then it was separated high and low molecular weight fraction by ethanol precipitation, The high molecular weight fraction was found to be a proteoglycan composed of glucose, mannose, galactose, xylose, fructose, ribose and amino acids. The amino acids of proteoglycan were mainly threonine, isoleucine, glycine, aspartic acid. Anticomplementary activity of the high molecular weight fraction was higher than that of the low molecular weight fraction. And also, the high molecular weight fraction enhanced phagocytic activity and nitric oxide production of macrophage. In enzymatic lipid peroxidation reaction with $ADP-FeCl_3-NADPH$, the lipid peroxidation was inhibited 82.4% and 86.6% by high and low molecular weight fractions, in nonenzymatic lipid peroxidation reaction, it was 83.0% and 84.6%, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.569-573
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• 2001

A pectic substance from citron peel was extracted with different methods to establish the optimum extraction conditions. The extraction yields of pectin with HCl, citrate and tartrate (concentration : 0.1 N, extraction ratio : 1 : 20) were 17.9%, 15.6% and 11.4%, respectively. Six times of 65% ethanol washing step was followed after first ethanol precipitation of acid extract for pure pectin. The degree of esterification (DE) of pectins was in the range of 43.0~47.6% and intrinsic viscosity was in the range of 0.94~2.63 (η$_{sp}$ /C (dL/g)). The sugar compositions such as rhamnose, xylose, glucuronic acid, galacturonic acid, galactose and glucose were little different in three kinds of pectins except for the content of arabinose.