• KSBB Journal
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• 제17권2호
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• pp.137-141
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• 2002

산가수분해법과 칼럼크로마토그라피법을 이용하여 레반 올리고당과 저분자량 레반을 생산하였다. 레반에 대한 산가수분해반응은 시간의존적으로 비례적으로 진행되었으며, 다른 미생물 유래의 레반을 사용시에도 동일한 결과를 나타내었다. 레반 올리고당의 제조를 위한 최적화된 조건은 5% 레반을 0.38 M 황산, 95$^{\circ}C$, 4분간 처리하였을 때였으며, 최종생산물로 중합도 3-6의 레반 올리고당을 얻었다. 생성된 레반을 올리고당을 탄소 원으로 이용하여 두 젖산 생성균주(Lactobacillus plantaurm KCTC 3104와 Pedioccccus pentosaceus KCTC3507)의 생장배지에 첨가하고 레반 자체를 첨가한 배지와 비교시, 뚜렷한 생육촉진효과와 pH 감소효과가 나타났다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권6호
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• pp.582-586
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• 2005

In this Study, we have attempted to determine the effects of dietary fructose polymers (fructan), high molecular-weight ${\beta}-(2,6)-linked$ levan, and low-molecular-weight ${\beta}-(2,1)-linked$ inulin, on two intestinal enzymes $({\beta}-glucuronidase\;and\;{\beta}-glucosidase)$. As a preliminary experiment, when intestinal microflora were cultured in anaerobic media harboring levan or its oligosaccharides, bacterial cell growth was observed in the levanoligosaccharide-supplemented media, but not in the levan-supplemented media, indicating that levan's size is important for the utilization by intestinal bacteria of levan as an energy Source. In our animal study, the intake of a levan-rich diet was determined to significantly attenuate the activity of the harmful enzyme $({\beta}-glucuronidase$, but d id not affect the activity of ${\beta}-glucosidase$.

• Journal of Microbiology and Biotechnology
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• 제14권6호
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• pp.1232-1238
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• 2004

To investigate the production and characteristics of thermostable levan sucrase from Rahnella aquatilis ATCC 33071, the levan sucrase gene from R. aquatilis was cloned and expressed in Escherichia coli without induction system. Expression of levansucrase gene in E. coli had no notable or detrimental effect on the growth of host strain, and the recombinant levan sucrase exhibited levan synthesis activity. Levansucrase was secreted to the periplasm in E. coli, and addition of $0.5\%$ glycine yielded further secretion of levansucrase to the growth medium and resulted in an increase of total levansucrase activity. Furthermore, the cellular levansucrase was evaluated for the production of levan by using toluene­permeabilized whole-cells. The levansucrase was thermostable at $37^{\circ}C$. The molecular size oflevan was $1{\times}\;10^{6}$ Da, as determined by HPLC, and the degree of polymerization of levan varied with incubation temperatures: Low incubation temperature was preferable for the production of high-molecular size levan. The present study demonstrated that the mass production of levan and levan oligosaccharides can be achieved by glycine supplementation to the growth medium or by toluene­permeabilized whole-cells.

• 미생물학회지
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• 제34권1_2호
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• pp.37-42
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• 1998

토양으로부터 levan을 분해하여 단일종의 fructooligosaccharide를 생산하는 새로운 미생물을 분리 선별하여 본 연구의 공시균주로 선택하였다. Levanase 생산을 위한 최적 배지조성은 0.5% levan, 0.3% yeast extract 0.3% $NaNO_3$, 0.1% $K_2HPO_4$, 0.05% NaCl(pH 8.0)이었으며, 500ml용 shaking flask에 배지 50ml를 넣어 $30^{\circ}C$에서 54시간 배양시켰을 때 목적효소의 생산이 최대에 도달하였다. Levanase에 의해 생성되는 생성물은 단일종의 oligo당임이 확인되었으며 측쇄가 많은 levan으로부터는 소량의 측쇄구조를 가진 oligosaccharide로 추정되는 미지의 물질이 부산물로 생성되었다. 생성 oligo당을 순수하게 정제하여 HPLC 및 ESI-MASS로 중합도를 조사한 결과 DP가 7인 levanheptaose임이 판명되었다.

• Journal of Microbiology and Biotechnology
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• 제32권11호
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• pp.1373-1381
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• 2022

Fructan is a polysaccharide composed of fructose and can be classified into several types, such as inulin, levan, and fructo-oligosaccharides, based on their linkage patterns and degree of polymerization. Owing to its structural and functional diversity, fructan has been used in various fields including prebiotics, foods and beverages, cosmetics, and pharmaceutical applications. With increasing interest in fructans, efficient and straightforward production methods have been explored. Since the 1990s, yeast cells have been employed as producers of recombinant enzymes for enzymatic conversion of fructans including fructosyltransferases derived from various microbes and plants. More recently, yeast cell factories are highlighted as efficient workhorses for fructan production by direct fermentation. In this review, recent advances and strategies for fructan biosynthesis by yeast cell factories are discussed.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권5호
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• pp.339-344
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• 2004

A method for synthesizing branched fructo-oligosaccharides (BFOS) with a high concentration of sucrose ($1{\~}3$ M) was developed using levansucrase prepared from Leuconortoc mesenteroides B-1355C. The degree of polymerization of oligosaccharides synthesized according to the present method ranged from 2 to over 15. The synthesized BFOS were stable at a pH ranges of 2 to 4 under $120^{\circ}C$. The percentage of BFOS in the reaction digest was $95.7\%$ (excluding monosaccharides; $4.3\%$ was levan). BFOS reduced the insoluble glucan formation by Streptococcus sobrinus on the surfaces of glass vials or stainless steel wires in the presence of sucrose. They also reduced the growth and acid productions of S, sobrinus. Oligosaccharides can be used as sweeteners for foods such as beverages requiring thermo- and acid-stable properties and 3s potential inhibitors of dental caries.