• Microbiology and Biotechnology Letters
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• v.18 no.5
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• pp.490-495
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• 1990

The extracellular inulinase from Bacillus spp. was purified to a single protein through a sequence of operations including ammonium sulfate fractionation, heat treatment, DEAE Sepharose C1-6B ion exchange chromatography, Sephadex 6-100 and Sephadex 6-150 gel filtration. The purified enzyme was confirmed to be a $\beta$ -D-fructofuranosidase(EC 3.2.1.26) which was much more active on sucrose than on inulin(I/S = 0.2). The maximal inulinase activity was observed at pH 6.0 and at the temperature of $50^{\circ}C$. The mo1ecular weight of the enzyme was about 56, 000. Tryptophan and histidine residues of the enzyme molecule were found to be essential for its catalytic activity.

• Microbiology and Biotechnology Letters
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• v.22 no.2
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• pp.152-157
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• 1994

Inulinase of Kluyveromyces marxianus origin was produced by recombinant yeast Saccharomyces cerevisiae under the control of GAL1 promoter, to examine the expression and localization of inulinase in a repressed(galactose-free) or derepressed(galactose-containinga) medium. The inulinase gene(INU1A) was constitutively expressed at 6.7 units/ml in a repressed medium. When the cell started to utilize galactose in a derepressed medium, the INU1A gene began to be expressed, and the final expression level reached about 45 units/ml. According to be the nondenaturingPAGE analysis, inulinase produced by S. cerevisiae was found to be less glycosylated than the bakers yeast invertase. In addition, its glycosylation pattern was less heterogeneous than the K. marxianus inulinase. The supplementation of inulin or raffinose into the derepressed medium increased the cell growth rate, while the expression of INU1A was repressed. Regardless of the carbon sources examined, most of inulinase activity (more than 98%) was found in the extracellular medium, indicating excellent secretion efficiency.

• Journal of Microbiology and Biotechnology
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• v.20 no.7
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• pp.1101-1106
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• 2010

Pulsed electric field (PEF) of 1Hz, 1.5 kV, and 1ms increased the activities of catalase and inulinase over the whole range of applied Se concentrations compared with the non-treated cultures. A significant effect of selenium concentration (in the range of 5-14 ${\mu}g/ml$) on both intra- and extracellular enzyme activities was noted. At a Se concentration of 10 ${\mu}g/ml$, the activities of intra- and extracellular inulinases and extracellular catalase in the PEF-treated cultures reached the maximum of 71 U/g d.m., 46 U/g d.m., and approx. 8 U/ml, respectively. The maximum activity of intracellular catalase of approx. 6 U/ml (with and without PEF) was recorded at 5 ${\mu}g$ Se/ml. Further increasing of selenium concentration caused a decrease in the activity of the enzymes.

• Microbiology and Biotechnology Letters
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• v.23 no.5
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• pp.550-555
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• 1995

A strain of Pseudomonas sp. isolated from soil was shown to produce a high level of extracellular endo-inulinase. In this work, the endo-inulinase gene (inu1) of the bacterial strain was cloned into the plasmid pBR322 by using EcoRI restriction endonuclease and E. coli HB101 as a host strain. One out of 7, 000 transformants obtained from the above cloning experiment formed a clear zone around its colony on the selective medium supplemented with 2.0% inulin after a prolonged incubation at 37$\circ$C and subsequent cold shock treatment. The functional clone was found to carry a recombinant plasmid (pKMG50) with a 3.7 kb genomic insert containing the genetic information for the inulinase activity. The inulinase from E. coli HB101/pKMG50 was proved to be an endo-acting enzyme and produced constitutively in the recombinant E. coli cells. Zymogram of the enzyme from the recombinant cells with inulin substrate indicated that the molecular mass of the active protein was 190 Kd, while that of the endo-inulinase from the Pseudomonas strain was 170 Kd. This size discrepancy suggested that the inulinase from the recombinant E. coli HB101 cells might be the initial product of translation, not the mature form produced in the strain of Pseudomonas sp..

• Microbiology and Biotechnology Letters
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• v.16 no.6
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• pp.484-488
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• 1988

Two forms of extracellular endo-inulinase, designated as PIand P II were resolved from a species of Pseudomonas isolated from soil. Both enzymes were glycoproteins with their carbohydrate content of 15% for PIand 2.4% for P II inulinase. Tryptophan residue was proved to be an essential amino acid for their catalytic activity. The molecular weights of PIand P II were estimated to be 210, 000 and 170, 000, respectively. The activity of the two enzymes was strongly inhibited by p-chloromercuribenzoate but the inhibition was nearly completely offset by the addition of the reducing agents such as cysteine or dithiothreitol. On the other hand, the two enzymes were activated about 50-60% of their activities by the presence of Co$^{+2}$ ion, and quite stable at pH values ranging from pH 4.0 to 1.5. They also appeared to be relatively thermostable, and no appreciable inactivation was observed after incubation at 55$^{\circ}C$ for 2 hours. About 70 % hydrolysis rate with PIand 56 % with P II were achieved when inulin was hydrolyzed at 5$0^{\circ}C$ for 12 hours with 60 units of the enzymes in 2 % inulin solution.

• Microbiology and Biotechnology Letters
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• v.16 no.4
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• pp.259-264
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• 1988

Two forms of extracellular inulinase, designated as PI and PII were detected in the crude enzyme preparation from n species of Pseudomonas isolated from soil. PI and PII were purified to homogeneity by ammonium sulfate fractionation, DEAE Sephadex A-50 chromatography, Sephadex G-100 and Sephadex G-200 gel filteration. Both isoenzymes catalyzed specifically and endowise the cleavage of the $\beta$-2,1-fructofranoside linkage of inulin, and displayed no action upon sucrose, raffinose and levan. The optimal pH values for the PI and PII enzyme were pH 5.5 and 6.0, respectively and the highest activity of the two enzymes was observed at 55$^{\circ}C$. The Km values of PI and PII were calculated to be 2$\times$10$^{-3}$M and 5$\times$10$^{-3}$M, respectively.

• KSBB Journal
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• v.11 no.4
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• pp.445-452
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• 1996

To investigate the promoter effect on heterologous gene expression in S. cerevisiae, the recombinant plasmids pYI11, pYI12, pYI10-2, and pYIGP were constructed to contain the inulinase gene (INUI) as a reporter under the control of GAL10, GAL7, GAL1, and GAP promoters, respectively. When the yeasts transformants were cultivated on galactose-containing rich media, the cell growth reached to 36-39 OD600 at 72 hours of cultivation. The specific growth rates of the cells harboring the four different plasmids decreased similarly : they dropped from $0.24 h^{-1}$ during the glucose-consuming period to 0.04 -$0.10 h^{-1}$ during the galactose-consuming period (gene expression phase for GAL promoter system). After the depletion of glucose, the expression of inulinase gene was started and reached to maximal levels of 4.3(GAL1 promoter), 4.0(GAL10 promoter), 3.8(GAL7 promoter), and 1.6(GAP promoter) unit/mL at 72 hours of cultivation. Based on the maximal expression level and activity staining on the plate, the promoter strength was in the order of GAL1, GAL10, GAL7 and GAP promoter. While the GAL-promoter systems showed a high plasmid stabilities of more than 78%, the GAP-promoter plasmid revealed a lower plasmid stability of 55%. Most of inulinase activity (98%) was found in the extracellular medium, indicating that the secretion efficiency of inulinase is independent on the type of promoter.

• Journal of Life Science
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• v.8 no.5
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• pp.614-621
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• 1998

An extracellular inulinase from Penicillium sp. which isolated from soil sample was purified to a single protein th-rough ammonium sulfate fractionation, DEAE-Sephacel ion exchange chromatography and Toyopearl HW 65 F gel filtration. The temperature and pH for the enzyme reaction were around 6$0^{\circ}C$ and 4.0, respectively. The enzyme was stable at 3$0^{\circ}C$-5$0^{\circ}C$ and in the pH range of 4 to 5. $CuCl_2$, $HgCl_2$ and EDTA inhibited the enzyme activity strongly. By contrast, $MnCl_2$ and $CaCl_2$ activated the enzyme activity. The molecular weight of the purified enzyme was esti-mated to be 77,000 dalton by SDS-polyacrylamide gel electrophoresis. The Km values of the enzyme for inulin were calculated to be $2.2\times10^{-3}$M. TLC analysis suggested that purified enzyme is exo-type inulinase. The NH2-terminal amino acid sequences of the purified enzyme was determined to be $NH_2$-X-Glu-Ser-Tyr-Thr-Glu-Lys/Leu-Tyr-Arg-Pro.

• Journal of Microbiology and Biotechnology
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• v.7 no.2
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• pp.121-126
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• 1997

A bacterial strain LC-413, producing an extracellular inulin fructotransferase (depolymerizing) which converts inulin into di-D-fructofuranose dianhydride (DFAIII), was isolated from soil. Inulin fructotransferase from the isolate identified as a strain Flabobacterium sp. was purified from the culture broth by ammonium sulfate precipitation, followed by column chromatograpies on DEAE-Toyopearl 650 M and phenyl-Toyopearl 650 M. The purified enzyme gave a single band on an electrophoretic disc-gel. The molecular weight of the enzyme was estimated to be 44, 000 Da by SDS-polyacrylamide gel electrophoresis, and 45, 000 Da by gel filtration, suggesting the monomeric state of the enzyme. The isoelectric point of the enzyme was about pH 4.5. The optimal pH and temperature for the enzyme reaction were 6.0 and $50^{\circ}C$, respectively. The purified enzyme digested inulin into di-D-fructofuranose-l, 2': 2, 3'-dianhydride, confirming the enzyme was an inulin fructotransferase (inulinase II).

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.921-928
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• 2002

Microorganism producing extracellular CFTase was isolated from soil and designated as Bacillus polymyxa MGL21. The gene encoding the CFTase (cft) from B. polymyxa MGL21 was cloned and sequenced. The ORF of the cf gene was composed of 3,999 nucleotides, encoding a protein (1,333 amino acids) with a predicted molecular mass of 149,375 Da. Sequence analysis indicated that CFTase was divided into five distinct regions. CFTase contained three regions of repeat sequences at the N-terminus and C-terminus. The endo-inulinase region of homology (ERH) of CFTase was similar to that of Pseudomonas mucidolens endo-inulinase ($50\%$ identity, 259 amino acids). Furthermore, CFTase possessed a highly conserved core region, which is considered to be functional for the hydrolysis reaction of inulin. The cft gene was expressed in a His-tagged form in Escherichia coli cells, and the His-tagged CFTase was purified to homogeneity. The optimal temperature and pH for CFTase activity were found to be $50^{\circ}C$ and 9.0, respectively. The enzyme activity was completely inhibited by 10 mM $Ag^+\;and\;Cu^2+$. Thin-layer chromatography analyses indicated that CFTase catalyzed not only the cyclization reaction ut also disproportionation and hydrolysis reactions as well.