• Journal of Microbiology and Biotechnology
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• 제7권3호
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• pp.204-208
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• 1997

Aureobasidium puliulans possesses the capacity for simultaneous formation of fructosyltransferase and glucosyltransferase in various sugar media including sucrose, maltose, glucose and fructose. Among them, sucrose (300 g/1) was the most suitable carbon source for fructosyltransferase production, while fructose (100 g/1) gave the maximal production of glucosyltransferase. There existed a critical concentration for the optimal formation of enzymes in sucrose, glucose and fructose media. By contrast, no effect of maltose concentrations up to 300 g/1 was observed. The specific activity of the glucosyltransferase on maltose medium was highest during the early period of fetmentation, after which a sharp decrease occurred, whereas fructosyltransferase activity on sucrose medium maintained a nearly constant rate for a given culture period. Concomitant production of fructosyltransferase and glucosyltransferase was investigated with different combinations of lower concentrations of sucrose and maltose. Maltose supplementation in sucrose media and sucrose addition to maltose media enhanced the activity ratios of fructosyltransferase to glucosyltransferase as compared to that of non-supplemented media. Several polymers and surfactants were added in an attempt to enhance enzyme production, and supplementation of polyoxyethylene-sorbitan monolaurate (Tween 20) promoted fructosyltransferase production by 20%.

• 한국식품영양과학회지
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• 제26권3호
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• pp.534-539
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• 1997

In order to reuse enzyme efficiently, a mthod for ionic binding of fructosyltransferase to a porous carrier bearing quaternary alkyl alkanolammonium groups was investigated. The fructosyltransferase activity of the immobilized enzyme increased with increasing amount of loaded enzyme, and maximally reached 770U/g of the carrier when loaded amount of the enzyme was 18.2 mg/g carrier. The immobilized fructosyltransferase had optimum pH and temperature of 7.5 and 45$^{\circ}C$, respectively, whereas soluble enzyme had 6.5 and 55$^{\circ}C$: the Km value for the immobilized enzyme was 27.8 mM for sucrose, which was the same as that of soluble enzyme. In a batch reactor, the enzyme produced a mixture of fructooligosaccharides, mainly F$_2$G, from sucrose with the slight loss of enzyme activity during continuous operation of 12 days at 42$^{\circ}C$.

• KSBB Journal
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• 제9권1호
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• pp.40-47
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• 1994

Fructosyltransferase와 glucose oxidase의 혼합효소계를 이용한 고순도 fructo-oligosaccharides 생산반응에서의 수학적 모델을 제안하고 실험적으로 검증한 결과 실험치와 모델 값이 서로 잘 일치하였다. 혼합 효소계에서 두 효소의 kinetic parameters를 구한 결과, fructosyltransferase 단일 효소계에서의 값들에 비해 $K_m$ 값들은 감소하였고, $K_m,\;V_{max}$값들은 증가하였다. 혼합 효소계의 반응메카니즘은 전체적으로 Michaelis-Menten kinetics로 표현할 수 있었고, 제안된 모델을 이용하여 고순도 fructo-oligosaccharides 생산에 이상적인 설탕농도를 예측할 수 있었다.

• KSBB Journal
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• 제8권4호
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• pp.307-312
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• 1993

Polystyrene계 음이온 교환수지인 Diaion PA 412에 Aureobasidium pullulans 기원의 fructosyltransferase를 crude enzyme 상태로 고정화하여 fructo-oligosaccharides의 생산을 검토하였다. 고정화 효소의 최적 반응 pH 및 온도는 각각 pH 5.0, $55^{\circ}C$. 이었고 고정화에 의해 열안정성이 크게 증가하였다. 고정화 효소에 의한 fructo-oligosaccharids 생성의 효소 반응 경향은 free cell 및 soluble enzyme과 거의 유사하여 최종 반응산물 중의 당 조성 이 동일하였다. 고정화 효소를 repeated-batch 방법으로 운전하여 fructo-oligosaccharides 생산공정에 적용해 본 결과 $50^{\circ}C$에서 20일까지 안정성을 유지하였다.

• KSBB Journal
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• 제10권1호
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• pp.9-14
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• 1995

고정화 과당전이효소와 고정화 포도당 이성화 효소를 동시에 이용한 혼합효소계를 사용하여 새로운 조성의 프락토올리고당을 연속생산하였다. 혼합효소 반응에서 각 효소의 반응최적 온도 빛 pH 영역은 서로 상이하여, 고정화 과당전이효소의 경우 $65^{\circ}C$, pH 5.5에서 최고활성을 나타낸데 비해, 고정화 포도당 이성화 효소의 경우 실험범위내(온도 $80^{\circ}C$, pH 8 8)에서 온도와 pH가 높을수록 유리하였다. 고정화 효소의 열안정성은 과당전이효소 및 포도당 이성화 효소 모두 $50^{\circ}C$이후의 온도에서 불안정하였다. 고 정화 혼합효소의 비율이 프락토올리고당의 전환율에 미치는 영향을 검토한 결과, 과당전이효소와 포도당 이성화 효소의 비가 5:3 정도가 적당하였다. 최척 반응조건에서 생산된 프락토올리고당의 전환율은 66 %였고, 포도당으로부터 이성화되어 생성된 과당이 전체 반응물의 감미도를 6% 증가시켰다. 최적 반응 조건에서 고정화 혼합효소 반응기를 연속운전한 결 과. 40일 통안 초기 효소활성을 그대로 유지하였다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제1권1호
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• pp.18-21
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• 1996

A continuous production of fructooligosaccharides from sucrose was investigated by fructosyltransferase immobilized on a high porous resin, Diaion HPA25. The optimum pH(5.5) and temperature(55$^{\circ}C$) of the enzyme for activity was unaltered by immobilization, and the immobilized enzyme became less sensitive to the pH change. The optimal operation conditions of the immobilized enzyme column for maximizing the productivity were as follows: 600g/L of sucrose feed concentration, flow rate of superficial space velocity 2.7h-1. When the enzyme column was run at 50$^{\circ}C$, about 8% loss of the initial activity of immobilized enzyme was observed after 30 days of continuous operation, during which high productivity of 1174g/L$.$h was achieved. The kinds of products obtained using the immobilized enzyme were almost the same as those using soluble enzymes or free cells.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.527-529
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• 2003

A fructosyltransferase from Leuconostoc mesenteroides TL1 was purified. The molecular mass of the enzyme was estimated to be 38 kDa based on the activity staining. The pH and temperature optima of the enzyme were 6.3 and $40^{\circ}C$, respectivly. Structural analysis of the polymer prepared from sucrose by the enzyme was determined by NMR Spectroscopy: It shows the heterogeneous linkages of levan-like fructan and dextran-like glucan.

• KSBB Journal
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• 제19권5호
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• pp.368-373
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• 2004

The optimal condition for the production of a glucan and a fructan synthesizing enzymes from Leuconostoc mesenteroides NRRL B-1149 were studied based on the different medium compositions. Response surface methodology was applied to find the optimistic condition showing the relationship between the fermentation response (enzyme activities) and the fermentation variable concentrations of yeast extract, peptone concentration, K2HP04 concentration and sucrose. Optimum medium composition for both enzymes production was $0.75\%$ yeast extract, $0.72\%$ peptone, $1\%$ K2HP04 and $2.17\%$ sucrose. Using this medium, the activities produced in culture was 0.90 U/m~ for glucosyltransferase (GTase) and 0.96 U/ml for fructosyltransferase (FTase). After purification of 1149FTase by consecutive chromatographies using Sephadex G-150 and DEAE-Sepharose, a 1149FTase of 210 kDa on $7\%$ polyacrylamide gel was isolated and it synthesized soluble fructan. The 1149GTase showed a band of 180 kDa on $8\%$ polyacrylamide gel after purification using Bio-Gel P-100 gel chromatography and DEAE-Sepharose ion exchange chromatography and it synthesized insoluble glucan. The linkages of polymers were determined by methylation using Hakomori reagent and following NMR analysis. The glucan was composed of a(1~6) and a(1~3) linkages and the fructan was levan.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권2호
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• pp.100-104
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• 2006

In this study, we investigated the relationship between the morphology and the rheological properties of Penicillium citrinum to improve the production of neo-fructosyltransferase (neo-FTase). In a 2.5 L bioreactor culture of P. citrinum, it was observed that agitation speed and aeration rate had significant effects on the production of neo-FTase and that maximum cell mass and neo-FTase production obtained at 500 rpm and 1.5vvm were 8.14 g/L and $53.2{\times}10^{-3} U/mL$, respectively. Cell mass and neo-FTase production increased to 91.53 and 25.17%, respectively. In the morphology and rheology studies, P. citrinum showed a typical pellet morphology that was explained by a shaving mechanism; this phenomenon was significantly affected by carbon sources. The rheology of neo-FTase fermentation by P. citrinum was dependent on cell growth and fungal morphology.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.188-191
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• 2002

A glucan and a fructan producing enzymes from Leuconostoc mesenteroides NRRL B-1149 were prepared and concentrated from the cu1ture of 1.5% sucrose using polysulfone ultrafiltration hollow fiber in the presence of 0.1% (w/v) Tween 80, 1 mM $CaCl_2$, and 0.02% $NaN_3$. The molecular masses of the enzymes were estimated to be about 213.6 kDa and 180 kDa, respectively, based on the PAS staining for the glucosyltransferase and Mukasa method for fructosyltransferase. Polymers produced by the enzymes showed different solubility; an insoluble glucan and a soluble fructan. The linkages of polymers were determined by methylation using Hakomori reagent and following acid hydrolysis. The glucan was composed of ${\alpha}$-1,6 and 1,3 linkages and the fructan showed similar linkage data of levan.