• Journal of Applied Biological Chemistry
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• v.44 no.3
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• pp.113-118
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• 2001

Xylose (glucose) isomerase was purified to homogeneity from cell-extracts of Streptomyces chibaensis J-59 via ammonium sulfate precipitation followed by chromatography on DEAE-cellulose, and gel filtration on Sephacryl S-300. The purified enzyme is a homotetramer with a native molecular mass of 180 kDa and a subunit molecular mass of 44 kDa. The amino acid N-terminal sequence of glucose isomerase from S. chibaensis J-59 was determined to be Ser-Tyr-Gln-Pro-Thr-Pro-Glu-Asp-Arg-Phe-Thr-Phe-Gly-Leu. The first 14 amino acids of the N-terminal sequence of the enzyme showed strong analogies with N-terminal sequences of glucose isomerase produced by other Streptomyces spp. The optimum pH and temperature for activity were 7.5 and 85, respectively. The purified enzyme required $Mg^{2+}$, $Co^{2+}$, and $Mn^{2+}$ for the activity, $Mg^{2+}$ being the most effective. The enzyme was not inhibited by $Ca^{2+}$, but was inhibited by $Hg^{2+}$, $Ag^+$, and $Cu^{2+}$. The $K_m$, $V_{max}$, and $k_{cat}$ values of S. chibaensis J-59 isomerase for glucose were 83 mM, 40.9 U/mg, and $1,843min^{-1}$, respectively. In the presence of $Co^{2+}$, cell-free enzymes retained 100% without loss of activities by the heat-treatment at $70^{\circ}C$ for 7 days. The enzyme retained 50% residual activity after heating at $85^{\circ}C$ for 13.5 h, at $90^{\circ}C$ for 126 min. The enzyme is more thermostable than any other glucose isomerases of Streptomyces spp.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.89-93
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• 1993

In order to study the effect of the intestinal bacteria on the physiology of the human large intestinal tract, we isolated the intestinal bacteria of Koreans and tested the enzymatic patterns. Isolated Bifidobacterium sp. Int-57 showed the higher activity of ${\beta}-xylosidase$ than other intestinal microorganisms. The effect of the carbon sources, nitrogen sources, inorganic salts, initial pH and initial temperature on the production of ${\beta}-xylosidase$ of Bifidobacterium sp. Int-57 was investigated. The most suitable carbon source, nitrogen source and inorganic salt for the production of ${\beta}-xylosidase$ were 1.1% xylose, 0.4% yeast extract and 0.0003% $CoCl_2$ respectively at initial pH 7.0 and temperature $40^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.33 no.4
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• pp.486-491
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• 2001

The pathogenicity for one hundred strains of domestic and foreign Y. enterocolitica was tested with HEp-2 cell invasion method as a reference. The serotyping, biotyping, PCR and esculin hydrolyis, salicin fermentation, pyrazinamidase activity, indole production, xylose fermentation, CRMOX and autoagglutination were compared to determine the possibility of pathogenic detection method. According to the test results, serotyping was limited to verify pathogenicity, however, biotyping was quite related to pathogenicity up to 99%. The biotype 1A strains were non-pathogenic, while all strains of biotype $1B{\sim}4$ showed pathogenicity with the exception of one strain belonged to type 1B. The esculin and salicin test results were completely close and correlated to pathogenicity up to 99%. The HEp-2 cell invasion and pyrazinamidase test were related to pathogenicity by 95%. Biochemical tests such as D-xylose fermentation, CRMOX agar test and autoagglutination in broth were effective as a support test. It is strongly recommended that sequencial esculin test and PCR test could be done to verify pathogenicity of Y. enterocolitica as the easiest and accurate procedure.

• Clean Technology
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• v.17 no.1
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• pp.31-36
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• 2011

All types of ${\gamma}-Al_2O_3$ such as acidic, neutral and basic forms were chemically modified with (3-mercaptopropyl) trimethoxysilane (3-MPTMS) and oxidized by 30 wt% $H_2O_2$ solution. As a result, sulfonic acid modified ${\gamma}-Al_2O_3$ catalysts were obtained. Their formation was achieved more easily by treating 1M HCl solution. Their catalytic performance was tested by dehydration reaction of D-xylose to furfural. The sulfonic acid modified ${\gamma}-Al_2O_3$ catalysts showed high conversion (>90%) of D-xylose, and the selectivity to furfural was increased with the amount of sulfonic acid anchored on the catalyst.

• Microbiology and Biotechnology Letters
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• v.11 no.1
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• pp.23-32
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• 1983

In the present study, two kinds of D-xylanases (1, 4-$\beta$-D-xylan xylanohydrolase (EC 3.2.1.8) were purified and characterized from crude extract of Aspergillus niger KG79. Xylanase I was most active at pH 5.0, whereas xylanse II at pH 4.0 Both enzymes demonstrated their maximum activity at 45$^{\circ}C$. They were relatively stable between pH 4.0 and 6.0 at 3$0^{\circ}C$ for 6 hours. Molecular weight of xylanse I and II were 12, 500 and 11, 500, respectively. Michaelis-Menten constants of xylanse I and II were 0.28% and 0.26% of xylan, respectively. Both enzymes could degrade commercial D-xylan to xylose, xylobiose, and xylotriose to the degree of about 10% of total reducing power. Xylanse I could, however, liberate arabinose from barley straw xylan in addition to xylose and xylooligasaccharides more rapidly than xylanase II. The degree of hydrolysis was about 25%. The reconstituted D-xylanase system with purified xylanases and $\beta$-xylosidase degraded commercial xylan and barley straw xylan to the degree of 28% and 54% respectively. The limit of hydrolysis by the enzymes was suggested to be resulted from the physical structure of the substrate.

• The Korean Journal of Mycology
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• v.19 no.4
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• pp.276-281
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• 1991

Auxotrophs induced by UV irradiation were Iysine, arginine, methionine, and cysteine requirement. The optimal protoplast-producing conditions of Pachysolen tannophilus were obtained in 1 hr incubation treated zymolyase 0.5 mg/ml at $37-42^{\circ}C$(pH 6.5-8.5 with 0.6 M KCI as osmotic stabilizer. Cell volumn of fusants were counted in about 4 times of parents and their morphological characteristics were similar to parents which were global or egg-shaped, though in fusant, pseudohypha were observed frequently. Ethanol production of fusants were similar to parents, but arginine and methionine auxotrophs were showed increased ethanol production respectively 1.6 times and 1.25 times more than parents.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.4
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• pp.273-281
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• 1987

In this work the antioxidant effects of browning reaction products prepared by xylose-tryrtophan reaction system were discussed. The antioxygenic brown pigments were separated by solvent extraction, and column chromatography and isolated by gel filteration. The functional groups of the brown pigments which had antioxidant activity were examined. The brown pigments extracted with methanol showed antioxidant effect and were fractionated in 5portions on DEAE-cellulose column. The elutes with methanol: acetic acid(10:30 v/v sol n(A), methanol: chloroform(95:5 v/v) sol n(C), and chloroform: acetic acid(10:30 v/v) sol n(E) only showed antioxidant activity and their compositions were 22.43, 21.51 and $34.43\%$ respectively. When each fraction on DEAE-cellulose column was reseparated on Sephadex LH-20 column, 2 fractions were obtained from portion A and C respectively. Molecular weights of A, C and E fraction of brown pigments were from 2,600 to 3,700. By elucidation of IR spectra, the pigment fractions which showed a strong antioxidant activity were tearing the indole group. It is suggested that the antioxidant function of the brown pigment is due to hydroxy and amino group. A higher activity of the brown pigment fraction E might be attributed to carboxylic acid or carboxylic ester compounds.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.171-177
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• 2004

The endoxylanase (642 bp; 213 amino acids) and $\beta$-xylosidase (1,602 bp; 533 amino acids) genes from Bacillus sp. were amplified by PCR and separately inserted into the downstream of the yeast ADH1 promoters, resulting in the pAEDX-1 (7.63 kb) and pAEX (8.47 kb) plasmids, respectively. When the yeast transformants, S. cerevisiae SEY2102 harboring pAEDX-1 or pAEX, were grown on YPD medium, the total activities of the enzymes were approximately 9.8 unit/ml for endoxylanase and 2.9 unit/m1 for $\beta$-xylosidase. When the three kinds of xylan from oat spelts, birch wood, and corncob were hydrolyzed by treating with recombinant endoxylanase and $\beta$-xylosidase, it was found that xylose, xylobiose, and xylotriose were produced. To efficiently hydrolyze xylan, various reaction conditions such as amount of enzymes, substrate type, substrate concentration, temperature, and reaction time were examined. The optimized conditions for the hydrolysis of xylan were as follows: amount of endoxylanase, 10 units; amount of $\beta$-xylosidase, 10 units; temperature, $50^\circ{C}$; substrate type, oat spelts xylan; substrate concentration, 6%; reaction time, 1 h. Under the optimal condition, xylose was mainly produced from oat spelts xylan by cooperative action of endoxylanase and $\beta$-xylosidase.

• Korean Journal of Veterinary Research
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• v.33 no.2
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• pp.217-225
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• 1993

Commercial turkey poults not previously exposed to avian rotavirus were inoculated orally with the virus alone or in combination with E coki serotype 078 at 1, 7, 14 and 21 days of age. Turkey poults of 1, 7 and 14 days of age were susceptible to infection despite the presence of maternal antibodies against avian rotavirus in their serum. However, turkey poults at 21 days of age were less susceptible compared to those ages 1, 7 and 14 days. The clinical signs in poults of all ages were mild. Viral antigens were demonstrated in the mature villous epithelial cells of the duodenum, jejunum and ilem. Histopathological lesions were characterized by vacuolation of the epithelial cells and heterophil infiltration in infected turkey poults. A significant difference in D-xylose absorption was observed between control and rotavirus infected groups at 1 and 3 days post-infection in 14 days old turkey poults.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.114.2-114.2
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• 2011

Furfural is a versatile derivative. It can be utilized for a building-block of furfuryl alcohol production and a component of fuels or liquid alkanes. But in bio-process, furfural is a critical compound because it inhibits cell growth and metabolism. Furfural could be converted from xylose and usually produced from biomass in which hemicellulose is abundant. In this study, furfural production from miscanthus was performed and utilization of miscanthus residue was consequently conducted. At first, hydrolysis for investigation of miscanthus composition and furfural production was performed using sulfuric acid. Previously, we optimized dilute acid pretreatment condition for miscanthus pretreatment and the condition was found to be about 15 min of reaction time, 1.5% of acid concentration and about $140^{\circ}C$ of temperature and 60% (about 7 g/L) of xylose was solubilized from miscanthus. Using the xylose, furfural production was conducted as second step. Approximately $160{\sim}200^{\circ}C$ of temperature was accompanied with the hydrolysis for pyrolysis of biomass. When the investigated condition; $180^{\circ}C$ of temperature, 20 min of reaction time and 2% of acid concentration was operated for furfural production, furfural productivity was reached to be 77% of theoretical maximum. After reaction, residue of miscanthus was utilized as feedstock of ethanol fermentation. Residue was well washed using water and saccharified using hydrolysis enzymes. Hydrolysate (glucose) from saccharification was utilized for the carbon source of Saccharomyces cervisiae K35.