• Journal of Microbiology and Biotechnology
• /
• v.2 no.2
• /
• pp.78-84
• /
• 1992

Streptomyces sp. No.8, which produced glucose isomerase was isolated from soil samples. The isolated strain, No.8, was identified as belonging to the Genus Streptomyces. A mutant strain, SM 805, showed the greatest ability to produce glucose isomerase. It was developed from the strain, No.8, by mutagenesis induced by NTG and UV treatment. The mutant strain, SM 805, produced about 7 times more glucose isomerase than the parental strain, No.8. This enzyme catalyzed the isomerization of D-xylose, D-glucose and D-ribose. It was inactive in the absence of metal ions, but was activated by the addition of $Mg^{2+}$ or $Co^{2+}$. The optimum temperature and pH for enzyme activity were $80^\circ{C}$ and pH 8.5, respectively. The enzyme was stable in a pH range of 6.0 to 10.0, and it was highly thermostable. There was no activity loss below $80^\circ{C}$, and even above $90^\circ{C}$ about 45% of its activity was retained. The reaction equilibrium was reached when about 53% fructose was present in the reaction mixture. Whole cells containing glucose isomerase from Streptomyces sp. SM 805 were immobilized by glutaraldehyde treatment. The resultant immobilized enzyme pellets showed a relatively long stability during the isomerizing reaction. The half-life of the immobilized enzyme during the operating was 45 days in the presence of 10mM $Mg^{2+}$.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.6
• /
• pp.1002-1010
• /
• 2001

The D-xylose operon in Escherichia coli is known to be regulated by a transcriptional activator protein, XyIR, which is responsible for the expression of both xylAB and xylFGH gene clusters. The XyIR was purified to homogeneity by using the maltose binding protein fusion expression and purification systems involving two chromatography steps. The purified XyIR protein was composed of two subunits of 45 kDa, which was determined by both sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel filtration. The purified XyIR was specifically bounded to the xylA promoter, regardless of adding xylose to the reaction mixture, but binding of XylR was specifically bounded to the xylA promoter, regardless of adding xylose to the reaction mixture, but binding of XylR to the xylA promoter was enhanced by adding xylose. The enhanced binding ability of XyIR in the presence of xylose was not diminished by adding glucose. The presumed XyIR binding site is located between 120 bp to 100 bp upstream the xylA initiation codon.

• Microbiology and Biotechnology Letters
• /
• v.19 no.3
• /
• pp.296-302
• /
• 1991

Glucose isomerase producer, which produces 488 U/ml of glucose isomerase activity in 500 ml flask scale, was isolated among 666 isolates of Actinomycetes from pine forest soil samples. The isolate was identified as Streptomyces luteogriseus through the studies about morphology (spiral aerial mycelia), cell wall type (Type I), spore chains (spiral form), pigment formation (gray melanine pigment) & metabolism (sugar utilization etc). The optimum conditions of fermentation were determined in 500 ml flask scale. The enzyme production was reached maximum after 4 days at pH 6.0~8.0 and 27~$30^{\circ}C$ in the medium containing 1.5~3.0% of xylose; 0.5-0.8% of glucose; 0.1% of $MgSO_4.7H_20$; 0.05% of $CoCI_2-6H_20$; 7.5% of corn steep liquor.

• Korean Journal of Microbiology
• /
• v.18 no.2
• /
• pp.59-66
• /
• 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.

• The Korean Journal of Food And Nutrition
• /
• v.2 no.1
• /
• pp.1-11
• /
• 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).

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 1975.12a
• /
• pp.180.4-181
• /
• 1975

토양에서 분리한 한주인 Streptomyces sp. No.14를 당질인 xylose 및 xylan과 천연배지로 wheat Bran 및 Corn Cob를 함유한 영양배지에 배양한 결과 균체로부터 강력한 glucose isomerase를 생산하였다. 따라서 이 균주의 배양 및 효소적 특성을 몇 가지 조사한 결과는 다음과 같다.(중략)

• 한국생물공학회:학술대회논문집
• /
• 2005.10a
• /
• pp.519-519
• /
• 2005

• Journal of Microbiology and Biotechnology
• /
• v.28 no.4
• /
• pp.606-612
• /
• 2018

The enzyme xylose isomerase (E.C. 5.3.1.5, XI) is responsible for the conversion of an aldose to ketose, especially xylose to xylulose. Owing to the ability of XI to isomerize glucose to fructose, this enzyme is used in the food industry to prepare high-fructose corn syrup. Therefore, we studied the characteristics of XI from Anoxybacillus kamchatkensis G10, a thermophilic bacterium. First, the gene coding for XI (xylA) was inserted into the pET-21a(+) expression vector and the construct was transformed into the Escherichia coli competent cell BL21 (DE3). The expression of recombinant XI was induced in the absence of isopropyl-thio-${\beta}$-galactopyranoside and purified using Ni-NTA affinity chromatography. The optimum temperature of recombinant XI was $80^{\circ}C$ and measurement of the heat stability indicated that 55% of residual activity was maintained after 2 h incubation at $60^{\circ}C$. The optimum pH was found to be 7.5 in sodium phosphate buffer. Magnesium, manganese, and cobalt ions were found to increase the enzyme activity; manganese was the most effective. Additionally, recombinant XI was resistant to the presence of $Ca^{2+}$ and $Zn^{2+}$ ions. The kinetic properties, $K_m$ and $V_{max}$, were calculated as 81.44 mM and $2.237{\mu}mol/min/mg$, respectively. Through redundancy analysis, XI of A. kamchatkensis G10 was classified into a family containing type II XIs produced by the genera Geobacillus, Bacillus, and Thermotoga. These results suggested that the thermostable nature of XI of A. kamchatkensis G10 may be advantageous in industrial applications and food processing.

• Applied Biological Chemistry
• /
• v.39 no.6
• /
• pp.443-448
• /
• 1996

In order to investigate the function of xylA promoter(Pxyl) as regulatory region Pxyl-lacZ fusion gene was constructed by the insertion of xylA promoter to the multiple cloning site of upstream of lacZ gene in a multicopy numbered plasmid pMC1403 containing promoterless lac operon, which was designated pMCX191, and Pxyl-lacZ fragment from pMCX191 was inserted to low copy numbered plasmid pLG339, designated pLGX191. The expressions of ${\beta}-galactosidase$ in these recombinant plasmids containing Pxyl-lacZ fusion gene were induced strongly by the addition of xylose, repressed by the addition of 0.2% glucose in the presence of xylose. The catabolite repressions were derepressed by the addition of 1 mM cAMP as same as native xylA gene. The fragment of xylA promoter was partially deleted from the upstream of xylA promoter by exonuclease III to investigate the regulation site of xylA promoter and the degrees of deletion derivatives of xylA promoter were analyzed by the DNA base sequencing. By the investigations of the induction by xylose, repression by glucose and derepression by cAMP on xylose isomerase production, the regulation site of xylA promoter may be located in segment between -165 and -59 bp upstream from the initiation site of xylA translation.

• Microbiology and Biotechnology Letters
• /
• v.8 no.2
• /
• pp.125-133
• /
• 1980

A microorganism which produced D-glucose isomerase was identified to be similar to Streptomyces antibioticus on the morphological, cultural and physiological characteristics except the spore chain and the utilization of sucrose. D-xylose grown cells of Streptomyces sp. strain K-17 were disrupted by grinding with sea sand. D-glucose isomerase was partially purified with the fractionation by ammonium sulfate, Mn-treatment, DEAE-cellulose column chromatography, DEAE-sephadex (A-50) column chromatography and gel filtration of sephadex G-200. The enzyme was purified about 380 fold with 25 ％ recovery.