• Korean Journal of Microbiology
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• v.45 no.1
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• pp.63-68
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• 2009

The exo-polysaccharide producing microorganism, Aureobasidium pullulans IMS-822, was isolated and identified from soil. The viscosity-average molecular weight of exo-polysaccharide was calculated as $8.9{\times}10^5$ by Mark-Houwink equation. The sugar component of exo-polysaccharide was determined as glucose by HPLC analysis. The IR spectra indicated that the exo-polysaccharide has an absorption peak at 890 $cm^{-1}$ for the ${\beta}-configuration$ of D-glucan. The $^{13}C$ NMR signal at ${\delta}$ 86.62 ppm arose from the substituted C-3 of glucose. The signal at ${\delta}$ 72.11 ppm was assigned to C-6 of branched ${\beta}-(1{\to}3)-D-glucosyl$ residues. Viscosity and Congo red reaction indicated that {\beta}-(1{\to}3)(1{\to}6)-glucan$ produced by A. pullulans IMS-822 has a highly ordered hydrogen-bond dependent conformation in aqueous solution, which collapses in strong alkaline solution.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.171-172
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• 2002

• Proceedings of the Korean Society of Life Science Conference
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• 2006.09a
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• pp.111.2-111.2
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• 2006

• Proceedings of the Korean Society of Life Science Conference
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• 2002.03a
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• pp.75-75
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• 2002

• Proceedings of the Korean Society of Life Science Conference
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• 2002.03a
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• pp.76-76
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• 2002

• Proceedings of the Korean Society of Life Science Conference
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• 2002.03a
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• pp.77-77
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• 2002

• KSBB Journal
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• v.22 no.1
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• pp.1-6
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• 2007

The optimum liquid culture conditions were investigated for cell growth and polysaccharide production from liquid culture of Lentinus edodes. In flask culture, the optimal medium compositions for the polysaccharide production contained glucose 60 g/L, yeast extract 10 g/L, $KH_2PO_4$ 2.0 g/L, and $MgSO_4{\cdot}7H_2O$ 1.0 g/L. The maximum mycelial growth and polysaccharide production were 11.01 g/L and 1.64 g/L, respectively. In bioreactor, through the variation of aeration in order to increase mycelial growth and polysaccharide production, the maximum mycelial growth and polysaccharide production were 55.9 g/L at 8th day and 7.34 g/L at 7th day of cultivation with 1.5 vvm, respectively.

• Korean Journal of Microbiology
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• v.51 no.1
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• pp.68-74
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• 2015

Based on the genomic analysis of Thermococcus pacificus P-4, we identified a putative GH1 ${\beta}$-glucosidase-encoding gene (Tpa-glu). The gene revealed a 1,464 bp encoding 487 amino acid residues, and the deduced amino acid residues exhibited 77% identity with Pyrococcus furiosus ${\beta}$-glucosidase (accession no. NP_577802). The gene was cloned and expressed in Escherichia coli system. The recombinant protein was purified by metal affinity chromatography and characterized. Tpa-Glu showed optimum activity at pH 7.5 and $75^{\circ}C$, and thermostability with a half life of 6 h at $90^{\circ}C$. Tpa-Glu exhibited hydrolyzing activity against various pNP-glycopyranosides, with kcat/Km values in the order of pNP-${\beta}$-glucopyranoside, pNP-${\beta}$-galactopyranoside, pNP-${\beta}$-mannopyranoside, and pNP-${\beta}$-xylopyranoside. In addition, the enzyme exhibited exo-hydrolyzing activity toward ${\beta}$-1,3-linked polysaccharide (laminarin) and ${\beta}$-1,3- and ${\beta}$-1,4-linked oligosaccharides. This is the first description of an enzyme from hyperthermophilic archaea that displays exo-hydrolyzing activity toward ${\beta}$-1,3-linked polysaccharides and could be applied in combination with ${\beta}$-1,3-endoglucanase for saccharification of laminarin.

• The Korean Journal of Mycology
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• v.27 no.4 s.91
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• pp.304-311
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• 1999

Batch kinetics during the exo-polysaccharide (EPS) fermentation of Ganoderma lucidum was investigated as a function of different substrates (glucose and starch), substrate concentration $(1{\sim}7%,\;w/v)$ and subculture (3 times). Logistic model for mycelial growth fitted the experimental data better than Monod and two thirds power model. The Luedeking-Pirt equation was adequate to fit the kinetic data of product formation and substrate consumption. The EPS production was strongly non-growth associated, although it was mixed type. The product formation and sustrate consumption by growth associated mechanism decreased as the concentration of glucose increased, while those of the non-growth associated mechanism increased. However, starch medium increased the growth associated and non-growth associated substrate consumption indicating higher availability of substrate. Also, batch culture in starch medium showed the higher specific growth rate and stability during subculture than those in glucose medium. In conclusion, the enhanced EPS production and stability in the subculture was found to be remarkably improved by use of starch as sole carbon source in medium. The maximum mycelium dry weight and EPS production of 9.463 and 10.410 g/l, respectively, were obtained after shake culture of 7 days at $30^{\circ}C$ from the media containing 7% starch.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.287-292
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• 2005

The crude polysaccharides(C-CPF, C-CPM, C-CPB) derived from fruiting body, mycelia and mycelia free broth of cordyceps militaris were obtained by ethanol precipitation of hot water extracts. After a batch fermentation of C. militaris was carried out in a 5 L jar vessel, endo-polysaccharide and exo-polysaccharide were obtained. They were demonstrated as the hetero polysaccharides which were composed of glucsose, galactose and mannose by performed with HPAEC(high pH anion exchange chromatography) and conformation of random coil by its complex forming ability with congo red reagent. They were purified by ion exchange (DEAE-cellulose) and gel filtration chromatography. They were monitered by phenol-sulfuric acid method and Bradford method. The NO induction activities of crude polysaccharides and purified polysaccharides derived from mycelia free broth were enhanced rather than LPS(lipo polysaccharide) which was used as a general NO inducer. These effects presumably contibute to the antitumor activities. The homogenieties and molecular weights of polysaccharides were determined by using Sepharose CL-6B. The yield, molecular weights and NO induction activities of C-CPFN Fr.III, C-CPMN Fr.III, C-CPBN Fr.II were 0.387, 0.408 and 0.153, 127 K 210 K and 36 K, 40.79%, 88.72%, and 104.17%, respectively.