• KSBB Journal
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• v.15 no.6
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• pp.556-559
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• 2000

Cyclodextrin Glucanotransferase(EC 2.4.1.19 : 1,4-${\alpha}$-glucano) transferase, cyclizing; CGTase) can be separated and recovered in an aqueous two-phase system composed of poly(ethylene glycol)(PEG)/dextran and PEG/salt. In an aqueous two-phase system consisting of PEG 35000 (5%) and dextran T2000 (7%), all cell and debris were collected at the interphase. CGTase partitioned to the denser dextran phase at an yield of 83.4%. On the other hand, in an aqueous two-phase system consisting of PEG 35000 (10%) and sodium phosphate (15%), CGTase partitioned to the denser salt phase at an yield of 95.5%. In order to recover CGTase using an aqueous two-phase system, the PEG/salt system proved to be more efficient than the PEG/dextran system in terms of yield and cost.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.219-222
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• 1999

A simple sequence of membrane concentration and DEAE-Cellulose chromatography has been optimized to give a purified dextransucrase from Leuconostoc mesenteroides B-512FMCM with the highest specific activity (248.8 IU/mg protein) ever reported in high yield (overall 88.7%) for dextransucrase. When there was no sucrose in the dextransucrase and the dextran reaction digest, the dextransucrase hydrolyzed glucose from dextran. The glucose was transferred to the other glucoses from dextran and formed isomaltose and isomaltodextrin. The transglycosylation efficiency of glucose from dextran was much higher with acceptors. The dextransucrase can be used for the production of various kinds (or structures) of oligosaccharides using dextran and various acceptors with almost 100% theoretical yield.

• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.316-323
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• 1992

Studies on the changes in rheological properties, molecular weight distribution and dextran yield after being reacted in lO%(w/w) sucrose concentration were performed with crude dextransucrase produced from Leuconostoc mesenteroides isolated from Sikhae. The reaction rate of dextran formation was monitored by sugar analysis with HPLC and by the changes in apparent viscosity. According to the periodate oxidation test, the dextran produced in this experiment was estimated to have 89% $\alpha$-(1->6) main linkages and 11% $\alpha$-(1->) side linkages. The rheological properties of the dextran solution formed changed with reaction time, and it was related to the changes in molecular weight distribution of dextran as determined by GPC analysis. As the reaction proceeded, the rheological behavior changed from Newtonian to non-Newtonian, showing Binghampseudoplastic and thixothropic flow behavior. The apparent viscosity of dextran formed solution increased with increasing reaction time, reached a maximum value of 2680 cP ($\gamma$=$33.75s^{-1}$, $25^{\circ}C$) by enzyme reaction for 8 hours, and then decreased. The temperature dependency of dextran formed solutions was well expressed by the Arrhenius equation and the activation energy reached a maximum value of 1.69 kcal/mole by enzyme reaction for 8 hours.

• Journal of Microbiology and Biotechnology
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• v.2 no.2
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• pp.135-140
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• 1992

The partitioning of recombinant human interleukin-2(rhII-2) in PEG 8000-dextran 38800 aqueous two-phase system has been investigated using three different sources of rhIL-2. In the case of pure rhIL-2, the solubility in a PEG-dextran two-phase system was low and most of rhIL-2 was partitioned into the bottom phase. For the recovery of rhIL-2 from insoluble protein aggregates, the inclusion bodies of recombinant E. coli were solubilized by the treatment with sodium dodecyl sulfate (SDS). The addition of SDS significantly enhanced not only the solubility of rhIL-2 but also the partitioning of rhIL-2 to the top phase. When the ratio of SDS to rhIL-2 was 2.0, the partition coefficient(K) and the recovery yield(Y) at the top phase were 4.5 and 88%, respectively, at pH 6.8. In order to reduce the recovery steps further, SDS was directly added to the intact recombinant E. coli cells and then partitioned into the PEG/dextran aqueous two-phase system. The observed partition coefficient ($K{\cong{3.0$) and recovery yield ($Y{\geq}80%$ )of this method were comparable to the rhIL-2 recovery from insoluble protein aggregates. The results obtained in this work indicate that PEG-dextran two-phase partitioning might provide a simple way for the recovery and partial purification of recombinant proteins which are produced as inclusion bodies.

• KSBB Journal
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• v.5 no.2
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• pp.95-100
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• 1990

Ethanol fermentations of inulin by K.fraglis in aqueous two-phase system of PEG/Dextran were performed not only to investigate the characteristics of partition of ethanol, sugar, and cell in the upper phase and the bottom phase but also to compare the fermentation properties with those of single phase system. In the range of 1 to 3 wt% of Dextran, ethanol fermentability and ethanol productivity reduced according to the increase of the molecular weight of PEG. But the cell yield and the cell productivity showed the opposite trend. In the region of 6 to 10 wt% of PEG, the increase of the concentration of PEG, caused the minute decrease of ethanol productivity but the remarkable augmentation of cell productivity. According to the increase of the molecular weight of PEG, the partition coefficient of inulin slightly decreased. But with the increment of the concentration of Dextran, the partition coefficient and the partition yield of inulin in the bottom Phase represented the trends of increase.

• Journal of Food Hygiene and Safety
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• v.12 no.3
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• pp.228-233
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• 1997

Drug Dclivcry system (DDS) purpose to getting better remedial result by improving medication from ordinary methods. Applied for DDS, to improve selectivity and comtinuity during absorbing and delivery step, polmer drug (prodrug) was prepared by the esterification with dextran in such of biodegradable polymer and phthalylsulfathiazole with is efficient for entilitis. The polymer durg was prepared with dextran and phthalylsulfathiazole by the esterification. The synthetic procedures of polymer drug was performed by acid chloride and DCC methods. Polymer drug was synthesized in high yield by acid chloride method than DCC method. The antibiotic activities of polymer drug exhibited growth-inhibitory activity against Staphylococcus aureus, Staphylococcus epidermidis, E. coli, Salmonella typhimurium, Klebsiella pneumoniae at the concentration of 500 *g/m* in general through in vitro. As a result of test, polymer drug has 1/2 MIC than phthalylsulfathiazole. Also, it has high level MIC as much as phthalylsulfathiazole with Proteus, Pseudomonas. We conducted possibility of DDS as an applied for medicine with synthesized polymer drug by using natrural polymer. We consider that clinical research must be followed to verify safety and efficacy for controlled release, activity and toxicity.

• Journal of the Korean Applied Science and Technology
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• v.32 no.4
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• pp.758-766
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• 2015

Dextran is a generic term for a bacterial exopolysaccharide synthesized from sucrose and composed of chains of D-glucose units connected by ${\alpha}$-1,6-linkages by using dextransucrases. Dextran could be used as vicosifying, stabilizing, emulsifying, gelling, bulking, dietary fiber, prebiotics, and water holding agents. We isolated new strain capable of producing dextran from Korean traditional kimchi and identified as Leuconostoc sp. strain JYY4. Batch fermentation was conducted in bioreactor with a working volume of 3 L. The media was MMY and 15% (w/v) sucrose. Mineral medium consisted of $3.0g\;KH_2PO_4$, $0.01g\;FeSO_4$, $H_2O$, $0.01g\;MnSO_4$, $4H_2O$, $0.2g\;MgSO_4\;7H_2O$, 0.01 g NaCl, $0.05g\;CaCl_2$ per 1 liter deionized water. The pH of media was initially adjusted to 6.0. The inoculation rate was 1.0% (v/v) of the working volume. Temperature was maintained at $28^{\circ}C$. The agitation rate was 100 rpm. The production pattern of dextran was associated with the cell growth. After 24 hr dextran reached its highest concentration of 59.4 g/L. The sucrose was consumed completely after 40 hr. Growth reached stationery phase when sucrose became limiting, regardless of the presence of fructose or mannitol. When the specific growth rate was 0.54 hr-1, utilization averaged 5.8 g/L-hr. The yield and productivity of dextran were 80% and 2.0 g/L-hr, respectively. Dextrans produced by were separated to two different size by an alcohol fraction method. The size of high molecular weight dextran (45% alcohol, v/v), less soluble dextran, was between MW 500,000 and 2,000,000. Soluble dextran (55% alcohol, v/v) was between 70,000 and 150,000. The molecular weight average of total dextran (70% alcohol, v/v) was between 150,000 to 500,000. The enzymatic hydrolyzates of total dextran of ATCC 13146 showed branched dextrans by Penicillium dextranase contained of glucose, isomaltose, isomaltotriose, and isomaltooligosaccharides greater than DP4 (degree of polymerization) that had branch points. Compounds greater than DP4 were branched isomaltooligosaacharides. Hydrolysates by the Lipomyces dextranase produced the same composition of oligosaccharides as those by Penicillin dextranase.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.309-312
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• 2000

We investigated the effect of various additives on the freeze-drying efficiency of recombinant retrovirus. Trehalose was the more effective protectant compared with sucrose or glucose and the optimize trehalose concentration was 300 mM. To improve the effect of trehalose, trehalose-polymers mixtures were tested as protectants so that Poly(vinylpyrollidon)(PVP) improved the recovery yield slightly, but dextran and Poly(ethylenglycol)(PEG) showed a negative effect.

• Microbiology and Biotechnology Letters
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• v.27 no.1
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• pp.35-40
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• 1999

Alternan known as a kind of dextran is a linear and cyclic polysaccharide which is synthesized with sucrose by alternaansucrase (EC2.4.1.140) of Leuconostoc mesenteroides. But this polysaccharide is different from dextran in its structure and other properties. For the purpose of applying alternan for the food, cosmetic, and pharmaceutical industries, we isolated an excellent alternan-porducing strain, Leu. mesenteroides CBI-110. The optimum culture conditions were studied to improve the yield, and the activity of alternansucrase was increased up to 33U/ml in the optimum culture media. The concentrations of $Mn^{2+}$ and $Cu^{2+}$ ions were 0.01% and 0.03%, respectively, for the effective production of alternan. Finally, we obtained 25.6g/L of alternan.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.11a
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• pp.142-145
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• 2004

Anion-exchange porous hollow-fiber membranes with a thickness of about 1.2 mm and a pore size of about $0.30{\mu}m$ were used as a supporting matrix to immobilize cycloisomaltooligosaccharide glucanotransferase (CITase). CITase was immobilized to the membrane via anion-exchange adsorption and by subsequent enzymatic cross-linking with transglutaminase, the amount of which ranged from 3 to 110 mg per g of the membrane. The degree of enzyme multilayer binding was equivalent to 0.3 to 9.8. Dextran, as the substrate, was converted into seven- to nine-glucose-membered cycloisomaltooligosaccharides (CI-7, -8, and -9) at a maxi mum yield of $28\%$ in weight at a space velocity of 10 per hour during the permeation of $2.0(w/w)\%$ dextran solution across the CITase-immobilized porous hollow-fiber membrane.