• KSBB Journal
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• 제15권6호
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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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• 제9권2호
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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.

• 한국미생물·생명공학회지
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• 제20권3호
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• pp.316-323
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• 1992

가자미 식해에서 분리한 Leuconostoc mesenteroides(Sikhae)로부터 생산한 dextransucrase 조효소액에 10 sucrose를 반응시켜 얻은 dextran 생성액의 유변성과 생성된 dextran의 분자량 분포 및 수율을 반응시간별로 조사하였다. Dextran 생성속도는 반응액의 HPLC를 이용한 당분석과 점도측정으로 추정이 가능하였다. Periodate oxidation 시험결과 정제된 dextran은 89의 Alpha-(1-6) 결합외에 11의 Alpha-(1-3) 부결합이 존재하는 것으로 판단되며, 반응시간이 경과함에 따라 dextran 생성액은 높은 항복력을 갖는 Bingham-pseudoplastic 유체특성을 나타내었다. 반응시간이 결과함에 따라 시간의존 특성(thixothropicity)이 증가하였는데 이러한 현상은 GPC 분석을 통하여 dextran 생성액내 고분자 dextran의 비율증가에 의한 것임을 알 수 있었다. Dextran 생성액은 반응 8시간후에 최고점도 (2680 cP. $\gamma$=$33.75s^{-1}$, $25^{\circ}C$)를 나타내었으며, 그 이후부터 점도는 다시 감소하였다. 또한 dextran 생성액은 온도가 증가함에 따라 점도가 감소하였으며, 이는 Arrhenius의 일반식으로 표시할 수 있었다. Arrhenius 식으로 구한 dextran 생성액의 유동 활성화에너지는 반응시간이 경과함에 따라 증가하였으며, 8시간 반응시킨 dextran 생성액의 경우 1.69kcal/gmole 정도로써 온도증가에 의한 점도변화가 비교적 적음알 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제2권2호
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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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• 제5권2호
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• pp.95-100
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• 1990

균주 K.fragilis에 의한 이눌린의 PEG/Dextran 수성 이상계 알콜발효실험에서 알콜발효특성, 알콜 및 이눌린의 분배특성에 미치는 PEG분자량. PEG농도, Dextran농도의 영향을 구명하여 보았다. Dextran농도 1내지 3wt%범위에서 에탄올 발효능과 에탄올 생산성은 PET분자량 증가에 따라 감소하였으며 균체수율과 균체생산성은 그 반대 경향을 나타내었다. PEG농도 6내지 10wt%범위에서 윗상에서의 에탄올 배수율은 아랫상의 Dextran농도가 증가할수록 감소하였다. 이눌린 분배계수는 PEG분자량 증가에 따라 미세하게 감소하였으며, PEG농도에 영향을 받는 이눌린 분배특성은 분배계수, 분배수율 및 분배비이였으며. Dectran농도 증가에 따라 분배계수와 아랫상에서의 이눌린 분배수율은 증가하는 반면 이눌린 분배비는 감소경향을 나타내었다.

• 한국식품위생안전성학회지
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• 제12권3호
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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.

• 한국응용과학기술학회지
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• 제32권4호
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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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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.309-312
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• 2000

레트로바이러스를 동결 건조과정에서 발생하는 물리적, 화학적인 스트레스로 인한 바이러스의 실활을 보완하기 위해 첨가하여 준 여러 가지 첨가물 중 trehalose가 가장 탁월한 protectant임을 알 수 있었고 최적 첨가농도는 300mM이었다. Trehalose의 역할을 보완하기 위하여 분자량이 큰 polymer들을 첨가 하였으나 trehalose만을 넣어 주었을 때 보다 poly(vinylpyrollidone)(PVP)의 경우 큰 영향은 볼수 없었고 dextran과 PEG를 첨가 하였을 경우엔 오히려 더욱 활성이 감소하였다.

• 한국미생물·생명공학회지
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• 제27권1호
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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.

• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 추계 총회 및 학술발표회
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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.