• 한국식품과학회지
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• 제11권3호
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• pp.192-199
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• 1979

비교적 높은 역가의 포도당 이성화 효소를 생산하는 방사선균을 토양에서 선별하여 이성화 효소의 세포 고정화를 행하였다. 특히 최종 제품(pellet form)의 물리적 견고성을 얻기 위하여 세포를 $65^{\circ}C$로 15분간 열처리하고 선택적 건조를 행하여 얻은 세포 slurry를 가용성 전분과 섞은 후 사출시켜 pellet form으로 만들었다. 5% glutaraldehyde를 가교제로서 pellet 균괴를 3시간 처리함으로 효소의 세포 고정화를 이룩하였다. 최종 제품은 물리적 견고성이 양호하였고 효소의 회수율은 26%였으며 비활성도는 건물 g당 48.1 단위였다. 세포 고정화시킨 이성화 효소는 가용성 효소와 매우 유사한 효소학적 성질을 보여 주었다. 즉 최적 pH ; $7.5{\sim}9.0$, 최적 온도 ; $80{\sim}85^{\circ}C$, 활성화 에너지 ; 10.9 kcal/mole, 포도당에 대한 $K_m$값 ; 10.9 M이었다. 고정화 효소는 열안정과 pH 안정성이 양호함을 보여주었다.

• 한국식품영양학회지
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• 제2권1호
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• pp.1-11
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• 1989

Glucose isomerase (E.C.5.3.1.5) which reversibly catalyzes reaction between D-glucose and D-fructose was demonstrated in cell free extracts of alkalophilic Streptomyces sp. B-2 isolated from soil The optimum temperature, pH, and pH stability were 6$0^{\circ}C$, 10.5, and 7.8, respectively. The production of Gl in xylose and yeast extract was higher than that of other carbon source and nitrogen source. The Gl production was affected by Co2+ and Mg2).

• Preventive Nutrition and Food Science
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• 제1권1호
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• pp.117-120
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• 1996

To enhance cellulose hydrolysis f Humicola insolens cellulase (HIC) was empolyed with immobilized glucose isomerase(IGI). Optimun pH and temperature for HIC were 6.5 and 55$^{\circ}C$, respectively, whereas those for IGI were 7.0 and 60$^{\circ}C$, respectively. Optimun loading size of IGI was 200mg(130 untis) with 15units of HIC. Reaction conditions were determined to be as follows: 55$^{\circ}C$,pH 6.5, HIC 15 units and IGI 130 units. After 24h hydrolysis, more than 65% of avicel was converted to glucose and fructose; in contrast, the conversion ratio of control was 40%.

• Journal of Microbiology
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• 제43권1호
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• pp.34-37
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• 2005

In the present study, the xylA gene encoding a thermostable xylose (glucose) isomerase was cloned from Streptomyces chibaensis J-59. The open reading frame of xylA (1167 bp) encoded a protein of 388 amino acids with a calculated molecular mass of about 43 kDa. The XylA showed high sequence homology (92% identity) with that of S. olivochromogenes. The xylose (glucose) isomerase was expressed in Escherichia coli and purified. The purified recombinant XylA had an apparent molecular mass of 45 kDa, which corresponds to the molecular mass calculated from the deduced amino acid and that of the purified wild-type enzyme. The N-terminal sequences (14 amino acid residues) of the purified protein revealed that the sequences were identical to that deduced from the DNA sequence of the xylA gene. The optimum temperature of the purified enzyme was $85^{\circ}C$ and the enzyme exhibited a high level of heat stability.

• 한국미생물·생명공학회지
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• 제19권4호
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• pp.405-412
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• 1991

토양에서 분리한 glucose isomerase 생산균주인 Streptomyces luteogriseus TH34를 0.05% chitosan과 0.28 glutaraldehyde를 이용하여 고정화시켜 역가가 기존 시제품보다 우수한 535IGIC/g인 효소를 얻었다. 한편 효소를 세포파괴 후 60% $(NH_4)_2S0_4$ fractionatioin, DEAE-Cellulose 및 Sephadex G-150을 이용하여 분리, 정제하여 6.3배 정제된 효소를 얻었고 고정화시킨 효소와 특성을 비교하였다. 효소의 분자량은 140,000이었고 분자량 35,000의 4개 subunits로 구성되어 있으며 최적 반응온도는 정제효소, 고정화효소에서 각각 $75^{\circ}C$, $80^{\circ}C$이고 열안전성은 공정화 효소가 높았으나 두 효소는 다 같이 $80^{\circ}C$이고 열안전성은 고정화 효소가 높았으나 두 효소는 다같이 $80^{\circ}C$에서 20분 처리시 역가 감소가 거의 없었다.

• 한국미생물·생명공학회지
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• 제7권1호
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• pp.9-14
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• 1979

독보리짚을 NaOH로 처리하여 헤미셀로오즈 부분을 추출하여 이것을 Streptomyces flavogriseus에 의한 글루코오스 이성질화효소를 생성하는데 사용하였다. 짚을 1%~24%의 NaOH를 처리함으로써 천연 헤미셀룰로오즈를 농도 25%까지 얻을 수 있었고 헤미셀룰로오즈 수율은 NaOH농도를 4%까지 증가시킬 때까지는 비례적으로 증가하였다. 그러나 증가율은 NaOH 농도가 더 증가하면 낮았다. 독보리짚에서 헤미셀룰로오즈를 추출하는 최적조건은 짚을 4% NaOH로 9$0^{\circ}C$에서 3시간 처리하거나 3$0^{\circ}C$에서 24시간 처리하여 균체를 2% 짚-헤디미셀룰로즈에서 3$0^{\circ}C$, 2일간 키웠을 때, 글루코오스 이성질화 효소활성도(3.04 units/ml 배양액)가 최고값에 달하였다. 또한 균체를 xylan, xylose 또는 짚의 황산가수분해물에 키웠을 때 글루코오스 이성질화 효소를 상당한 량을 생성되었다. 헤미셀룰르오즈를 추출해내고 남은 짚 찌꺼기는 동물 사료로 사용할 수 있는데, 이는 젖을 갖 뗀 초원 들쥐에 그 찌꺼기를 사료로 주었을 때, 처리하지 않은 짚을 준 경우보다 75%나 더 높은 소화가 능도를 나타내며 사료로서의 효율은 20%가 더 높은 것으로 나타났음으로 알 수 있었다.

• 미생물학회지
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• 제18권2호
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• pp.59-66
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• 1980

Two strains S-P and S-P-2, both Streptomyces sp., have been isolated and were found to have relatively high specific enzyme activity compared to other organisms reported. The specific activity of the enzyme produced from these two strains were 0.25 and 0.2 international units respectively. The productivity of the enzyme achieved was about 50 IU/l/hr. Glucose isomerase form these strains was found to be stable under the temperature of heat treatment (at $65^{\circ}C$) for fixation of enzyme inside the dell. This organism has an advantage in that it did not require toxic metalic ion for enzyme activity and could utilize xylan in leu of xylose as an inducer. The optimal temperature and pH of enzymatic reaction purpose of using these data for the optimal operation and designing of enzyme reactor system. The reaction mechanism was found to follow the single substrate reversible reaction kinetics. The kinetic constants determined experimentally are : $K_{mf}=0.33M,\;K_{mb}=1.0M,\;V_{mf}=0.88{\mu}mole\;per\;min.,\;V_{mb}= 2.96{\mu}mole\;per\;min.\;and\;K_{eq}=0.74.

• 미생물학회지
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• 제15권1호
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• pp.9-19
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• 1977

Xylone isomerase (D-xylose ketol-isomerase, EC 5,3,1,5) have been demonstrated in the cell-free extracts of Stroptomuces canus and Streptomuces malachiticus grown in the presence of xylose. Xylose, glucose and ribose served as substrates for the enzymes of the two strains with respective $K_m$ values of 22, 130, 290 mM (S. canus) and 7,83,637 mM(S.malachiticus), and $V_max$ values of 1,000, 0.087, $\0.0222{\mu}moles/min/mg$ protein (S. canus) and 0.312, 0.083, 0.500.$\mu$moles/min/mg protein (S. malachiticus). L-Rhammose was also isomerized by the crude enzyme solutions of the two strains. The maximal activities of the two xylose-isomerases were observed at pH 7.5 and $75^{\circ}C$. The xylose isomerase activities of the two strains were activated two-three times by $Mg^{++}\;and\;Co^{++}$ as that of control, partially activated by $Ba^{++}$ and inhibited by $Ni^{++},\;Ca^{++}\;and\;Zn^{++}\$. Particulary, the addtion of $Mn^{++}$ stimulated xylose-isomerizing activities, but inhibited glucose-isomerizing activities in both strains. However, $Cu^{++}$ inhibited xylose-isomerizing activities, while stimulated glucose-isomerizing activities of the enzymes.

• 미생물학회지
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• 제21권2호
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• pp.51-60
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• 1983

Cultural characteristics of Strptomyces griseolus isolated from the soil were investigated. This strain was disclosed to utilize D-xylose, and D-glactose in preference order as a carbon source with the formation of glucose isomerase. The addition of sweet potato starch also proved effective promoting the total enzyme activity measured at 29% higher than the control. Corn cob, one of waste agricultural resources, was hydrolyzed in 2~3% $H_2SO_4$ solution at $100^{\circ}C$, 3~5 hours to produce a xylose syrup which gave rise to the recovery of 19.9% in a batch system and 28.2% in a repeated system. By the addition of both 2% of xylose syrup(Be'28) prepared by and us 65% of corn steep liquor (total nitrogen 1.2%), enzyme induction was maximized. The enzyme activity was stimulated by the xylose and the cell growth by the C.S.L. Also, remarkable increase of enzyme activity was noticed by the addition of protein acid hydrolysate 86.2% higher than the control. $QO_2$ of the biomass cultured in 30L capacity jarfermentor recorded low oxygen requirement of 251.2 1/hr. Maximum activity of glucose isomerase was observed noted at the 9th hour after inoculation which is 2 hours faster than the stationery was observed noted at the 9th hour after inoculation which is 2 hours faster than the stationery phase of the biomass growth. Glucose isomerase from the strain was activated by adding the $Co^{++}\;and\;Mg^{++}$ with optimum temperature of $73^{\circ}C$ and pH of 7.2. Conversion ratio of 60% glucose to frutose was 42.5% after 70 hours reaction.

• 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.