• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.630-634
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• 2011

Enzymatic hydrolysate of porphyran from Porphyra yezoensis was prepared by treatment with ${\beta}$-agarase. The hydrolysate was fractioned into molecular sizes of <3, 3-30, and 30-300 kDa using an ultrafiltration membrane. The membrane fractions were further separated into neutral and anionic fractions using Dowex $1{\times}8$ ion exchange chromatography. After hydrolysis of porphyran with ${\beta}$-agarase, 23.2% of the starting porphyran was recovered as a neutral fraction of low-molecular weight (<3 kDa), and 28.9% remained as an enzyme-resistant anionic fraction of high molecular weight (>300 kDa). Desulfation of porphyran and $^{13}C$-NMR analysis of the anionic fraction of low molecular weight (<3 kDa) showed that the anionic fraction has a backbone consisting of 3-linked ${\beta}$-D-galactose units alternating with either 4-linked a-L-galactose 6-sulfate or 3, 6-anhydro-a-L-galactose units. These results indicate that porphryan is a copolymer of two moieties, about 25% of which are composed of neoagarose moieties and 75% as anionic moieties.

• KSBB Journal
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• v.22 no.4
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• pp.201-206
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• 2007

The demand of L-arabinose has been increased recently because of its advantages including clinical effect. L-arabinose can be produced from dilute acid hydrolysis of agricultural wastes. In this study, optimum conditions of L-arabinose production using dilute acid hydrolysis of agricultural wastes and nutshells were determined. Among the tested various agricultural wastes and nutshells, corn fiber was selected as the best raw material for the production of arabinose. The highest arabinose production was achieved an acid hydrolysis of corn fiber for 1 h at 130$^{\circ}C$ with 0.4% sulfuric acid. Above optimal conditions, it was obtained 20.1 g/L glucose, 10.1 g/L xylose, 7.8 g/L arabinose and 1.8 g/L galactose from 90 g/L of corn fiber. For the purification of arabinose, it was carried out to remove all of sugars except arabinose by the Candida tropicalis cultivation of acid hydrolyzate and an organic contaminants such as pigments by the active carbon treatment of fermentation broth. Moreover, experiments were carried out to eliminate an ions by exchange chromatography. Finally, we obtained 3.1 g of partially purified L-arabinose powder with about 40% yield by evaporation and vacuum drying.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.3
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• pp.183-186
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• 2003

The artificial gene coding for anticoagulant hirudin was placed under the control of the GAL 10 promoter and expressed in the galactokinase-deficient strain (Δgal1) of Saccharomyces cerevisiae, which uses galactose only as a gratuitous inducer in order to avoid its consumption. For efficient production of recombinant hirudin, a carbon source other than galactose should be provided in the medium to support growth of the Δgal1 strain. Here we demonstrate the successful use of glucose in the fed-batch fermentation of the Δgal1 strain to achieve efficient production of recombinant hirudin, with a yield of up to 400 mg hirudin/L.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.123-125
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• 1996

The orientation effect of galactose ligand on hepatocyte attachment was investigated. Poly(N-p-vinyl benzyl-o-${\beta}$-D-galactopyranosyl-D-gluconamide) (PVLA), a ${\beta}$-galactose-carrying styrene homo-polymer, was used as a model ligand for the asialoglycoprotein receptors on hepatocytes. PYVA was transferred onto the poly(${\gamma}$-benzyl L-glutamate)(PBLG) or PBLG/ poly(ethylene glycol)(PEG)/PBLG Langmuir-Blodgett (LB) films as the monolayer level. The dichroic fluorescence values of confocal microscope indicated that the PVLA transferred onto the LB films was located with a preferential orientation of its molecular axes with regard to the direction of the a-helix of polypeptide. Hepatocyte recognized well-oriented galactose moieties of the surface of PVLA through asialoglycoprotein receptors.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.52-52
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• 2001

Many nucleoside diphosphate (NDP) kinases are ubiquitous enzymes responsible for the exchange of ${\gamma}$-phosphates between tri- and diphosphonucleosides. The catalytic Many nucleoside diphosphate (NDP) kinases are ubiquitous enzymes responsible for the exchange of ${\gamma}$-phosphates between tri- and diphosphonucleosides. The catalytic reaction follows a ping-pong mechanism in which the enzyme is transiently phosphorylated on a histidine residue conserved in all nucleoside diphosphate kinases. Beside their role in nucleotide synthesis, these enzymes present additional functions, possibly independent of catalysis, in processes such as differentiation, cell growth, tumor progression, metastasis and development. To clone murine nm23-M5, several expressed sequence tags (ESTs) of the GenBank data base, selected according to their homology to nm23-H5 cDNA, reconstituted a complete open reading frame (GenBank AF222750). To test whether murine NDPKs (1, 2, 3, 4, 5, and 6) can inhibit Bax-mediated toxicity in yeast, co-transformation was performed respectively. The yeast S.cerevisiae was transformed with a copy expression plasmid containing the histidine selection marker and expressing murine Bax under the control of a galactose-inducible promoter. Several clones were selected and found to be growth inhibited when Bax expression was induced with galactose. A representative clone was transformed again with a copy expression plasmid containing the tryptophane selection marker and expressing either murine Bcl-xL or NDPK under the control of a galactose-inducible promoter. Several subclones of the double-transformants were selected and characterized. The ability of Bcl-xL and NDPKs to suppress Bax-mediated toxicity was determined by growing yeast cells overnight in galactose media and spot-testing on galactose plates starting with an equal number of yeast cells as determined by taking the OD$_{600}$. Ten-fold serial dilutions were used in the spot-test. Plates were grown at 3$0^{\circ}C$ for 2-3 days. All murine NDPKs suppressed Bax dependent apoptosis. Futher study will be peformed whether Bax-toxicity inhibition was caused by NDP kinase activity or additional function.n.

• Journal of Microbiology and Biotechnology
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• v.24 no.12
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• pp.1622-1628
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• 2014

DagA, a ${\beta}$-agarase, was produced by cultivating a recombinant Streptomyces lividans in a glucose medium or a mixed-sugar medium simulating microalgae hydrolysate. The optimum composition of the glucose medium was identified as 25 g/l glucose, 10 g/l yeast extract, and $5g/l\;MgCl_2{\cdot}6H_2O$. With this, a DagA activity of 7.26 U/ml could be obtained. When a mixed-sugar medium containing 25 g/l of sugars was used, a DagA activity of 4.81 U/ml was obtained with very low substrate utilization efficiency owing to the catabolic repression of glucose against the other sugars. When glucose and galactose were removed from the medium, an unexpectedly high DagA activity of about 8.7 U/ml was obtained, even though a smaller amount of sugars was used. It is recommended for better substrate utilization and process economics that glucose and galactose be eliminated from the medium, by being consumed by some other useful applications, before the production of DagA.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.606-607
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• 2005

• Korean Journal of Microbiology
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• v.27 no.3
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• pp.181-187
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• 1989

Plasmid DNA was isolated from Lactobacillus casei SW-M1($Lac^{+}$strain). The curing frequencies of pPLac plasmid from L. casei SW-M1 showed 43% for acriflavin treatment and 53% for ethidium bromide treatment after 3 times transfer. On the charaterization of pPLac plasmid, it was found that the plasmid contained gene encoding phospho-$\beta$-galactosidase for lactose utilization. Lactose-PTS(phosphotransferase system)was involved in membrane transport system in $Lac^{+}$ strain. Induction of phospho-$\beta$-galactosidase was specially effective by galactose, lower effect with lactose and glucose but not by IPTG(isopropyl-$\beta$-D-thiogalactoside). This result showed that induction of phospho-$\beta$-galactosidase by IPTG did not appeared. The catabolite repression of phospho-$\beta$-galactosidase synthesis by glucose was not found in L. casei.

• KSBB Journal
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• v.10 no.2
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• pp.221-229
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• 1995

Effects of carbon sources on zooglan production by Zoogloea ramigera were investigated. The production of zooglan was varied according to the carbon sources used. The largest amount of zooglan was obtained when lactose was used as carbon source and fermentation broth with lactose showed the higher viscosity. The effects of carbon sources were in decreasing order of lactose, glucose, galactose and sucrose. The viscosities of purified zooglan solutions (5g/L) obtained from different carbon sources were measured. When lactose was used, the viscosities of zooglan solutions was quite high and other carbon sources such as glucose and galactose gave little lower viscosities than lactose but sucrose gave very low values. On the other hand, it could be postulated that most of lactose is hydrolyzed by intracellular ${\beta}$-galactosidase.

• KSBB Journal
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• v.25 no.6
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• pp.539-546
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• 2010

In this work, mass production of Bacillus licheniformis SCD121067 through medium optimization by statistical experimental method was studied. First, galactose, yeast extract and potassium phosphate dibasic were selected as carbon, nitrogen and phosphate sources for mass production of B. licheniformis SCD121067 by using one factor at a time method. Second, according to the result of Plackett-Burman experimental design, key factors was yeast extract and $K_2HPO$. Finally, the response surface methodology was performed to obtain the optimum concentrations of two selected variables. The optimized medium composition consisted of 20 g/L galactose, 36 g/L yeast extract, 0.41 g/L $K_2HPO4$, 0.25 g/L $Na_2CO_3$, 0.4g/L $MgSO_4$ and 0.01g/L $CaCl_2$. Dry cell weight (15.4 g/L) by optimum production medium were increased 10 times, as compared to that determined with basic production medium (1.5 g/L). Fermentation conditions were examined for the mass production of B. licheniformis. The effect of temperature, agitation speed, pH and aeration rate on the mass production of B. licheniformis were also studied in a batch fermenter which was carried out in a 2.5 L bioreactor with a working volume of 1.5 L containing optimized production medium. As a result, dry cell weight of batch culture was 30.7 g/L at $42^{\circ}C$, 300 rpm, pH 8.0 and 2 vvm.