• Journal of Environmental Science International
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• v.14 no.10
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• pp.973-978
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• 2005

Biodegradable oil gelling agent was prepared, and their oil absorption capacities using light oil, lubricant oil and corn oil were investigated. The result showed that the oil absorption capacity was depended on the amount of surfactant and starch added, and was increased in the order of light oil, lubricant oil and corn oil. Also, the oil-absorption capacity was saturated within 30 min at $18^{\circ}C$. The biodegradability of the prepared biodegradable oil gelling agent was also studied by determination of reduced sugar produced after enzymatic hydrolysis. Their surface morphologies and thermal properties of the prepared biodegradable oil gelling agent were observed by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA), respectively.

• Food Science and Preservation
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• v.13 no.5
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• pp.563-568
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• 2006

The properties of mung bean were investigated depending on hydrolysis condition. The results showed that enzyme treatments (${\alpha}$-amylase and protease each at 0.1% (w/w)) by varying hydrolysis temperature showed better properties than non-pretense treatment (control group). The treatment with 0.08% ${\alpha}$-amylase was best for optimum hydrolysis of mung bean starch The treatment using a mixture of 0.08% (w/w) ${\alpha}$-amylase and 0.12% (w/w) protease was best for optimum hydrolysis of meg bean protein. The effects of Hydrolysis time of mung bean showed that the optimum time was 60 and 90 min and there fore the optimum time was set at 60 min. These result showed that the best hydrolysis conditions of mung bean were the treatment at $60^{\circ}C$ for 60 min using a mixture of 0.08%(w/w) ${\alpha}$-amylase and 0.12% (w/w) pretense, with the sugar level shown at $5.8^{\circ}Brix$, reducing sugar at 2,022.13 mg% and crude protein at 7,666.17 mg%.

• Journal of Microbiology and Biotechnology
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• v.4 no.1
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• pp.41-48
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• 1994

The xylanase from alkali-tolerant Bacillus sp. YA-14 was purified to homogeneity by CM-cellulose, Sephadex G-50, and hydroxyapatite column chromatographies. The molecular weight of the purified enzyme was estimated to be 20, 000 Da by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified enzyme slightly hydrolyzed carboxymethyl cellulose and Avicel, but did not hydrolyze soluble starch, dextran, pullulan, and ${\rho}-nitrophenyl-{\beta}$-D-xylopyranoside. The maximum degree of hydrolysis by enzyme for birchwood xylan and oat spelts xylan were 47 and 40%, respectively. The Michaelis constants for birchwood xylan and oat spelts xylan were calculated to be 3.03 mg/ml and 5.0 mg/ml, respectively. The activity of the xylanase was inhibited reversibly by $HgCl_2$, and showed competitive inhibition by N-bromosuccinimide, which probably indicates the involvement of tryptophan residue in the active center of the enzyme. The Xylanase was identified to be xylose-producing endo-type xylanase and did not show the enzymatic activities which cleave the branch point of the xylan structure.

• Journal of Microbiology and Biotechnology
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• v.17 no.5
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• pp.733-738
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• 2007

An extracellular exoinulinase($2,1-\beta-D$ fructan fructanohydrolase, EC 3.2.1.7), which catalyzes the hydrolysis of inulin into fructose and glucose, was purified 23.5-fold by ethanol precipitation, followed by Sephadex G-100 gel permeation from a cell-free extract of Kluyveromyces marxianus YS-1. The partially purified enzyme exhibited considerable activity between pH 5 to 6, with an optimum pH of 5.5, while it remained stable(100%) for 3 h at the optimum temperature of $50^{\circ}C$. $Mn^{2+}\;and\;Ca^{2+}$ produced a 2A-fold and 1.2-fold enhancement in enzyme activity, whereas $Hg^{2+}\;and\;Ag^{2+}$ completely inhibited the inulinase. A preparation of the partially purified enzyme effectively hydrolyzed inulin, sucrose, and raffinose, yet no activity was found with starch, lactose, and maltose. The enzyme preparation was then successfully used to hydrolyze pure inulin and raw inulin from Asparagus racemosus for the preparation of a high-fructose syrup. In a batch system, the exoinulinase hydrolyzed 84.8% of the pure inulin and 86.7% of the raw Asparagus racemosus inulin, where fructose represented 43.6mg/ml and 41.3mg/ml, respectively.

• Journal of Life Science
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• v.7 no.2
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• pp.95-106
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• 1997

The moderately alkalophilic bacterium, identified as Bacillus sp. S-1 , was isolated from soils and effectively secrete extracellular pullulanase. The isolate was moderately alkalophilic since enzyme production occurred at pHs from 6.0 to 10.0. Extracellular crude enzymes of the isolate gave maltotriose as the major product from soluble starch and pullulan hydrolysis. Compared to other alkalophilic microbes, this isolate secreted extremely high concentration(7.0 units/ml) of pullulanase. The purified pullulanase was moderately alkalophilic and thermoactive; optimal activity was detected at pH 8.0-10.0 and between 50-60$^{\circ}$C. Even at pH 12.0, 10% of S-1 pulluanase activity remained and the strain had broad pH ranges and moderate thermo-stability for their enzyme activities. These results indicate that the new isolate have potential as producer of pullulanase for use in the starch industry.

• Journal of Microbiology and Biotechnology
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• v.18 no.4
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• pp.725-729
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• 2008

An enzyme reactor installed with ultrafiltration membrane was developed to produce ${\alpha}-,\;{\beta}-$, and ${\gamma}$-cyclodextrins (CDs) from soluble starch by Bacillus macerans cyclodextrin glycosyltransferase (CGTase) tagged with 10 lysines at its C-terminus (CGTKIOase). Ultrafiltration membrane YM10 with 10,000 of molecular cutoff was chosen for membrane modification and CD production. A repeated-batch type of the enzyme reaction with free CGTK10ase resulted in a ${\alpha}$-CD yield of 24.0 (${\pm}1.5$)% and a productivity of 4.68 (${\pm}0.88$) g/l-h, which were 7 times higher that those for CGTK10ase immobilized on modified YM10 membrane. Addition of 1-nonanol increased CD yields by 30% relative to the control, which might be due to prevention of the reversible hydrolysis of CDs.

• Korean Journal of Microbiology
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• v.28 no.3
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• pp.229-235
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• 1990

A rapid and sensitive method to detect the extracellular enzymatic activity of bacteria colonies grown on agar plates is described. Selective agar media supplemented with protein, starch, chitin, Tween-80, etc. are conventionally used to detect biochemical properties of bacteria. It has been experimentally demonstrated with bacteria pure cultures that fluorogenic Methylumbelliferyl (MUF)-substrates are excellent substrate analogues for normally occurring polymers. Based on MUF-substrate hydrolysis the new method provides reliable qualitative estimates of extracellular enzymatic properties of bacteria within minutes using pure cultures as well as agar p;ates prepared for colony counts. Extracellular enzyme activities of heterotrophic bacteria from freshwater ecosystems and marine sediment using this method are discussed.

• The Korean Journal of Mycology
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• v.27 no.6 s.93
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• pp.386-393
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• 1999

Ethanol is considered as one of the most suitable substitutes for the petroleum, since it offers attractive functional features at an economical cost. Glucoamylase producing yeasts were isolated and characterized. Based on the morphological character, carbon fermentations, assimilation of carbon and nitrate, growth on vitamine-free medicine, and urease activity, five isolates of Saccharomyces diastaticus, two isolates of Saccharomycopsis fibuligera, and two of Schwanniomyces occidentalis, and each isolate of Ambrosiozyma monospora and Lipomyces kononenkoae were identified. Among 12 isolates, one of the S. diastaticus, E3 showed the highest activity of glucoamylase and identified as Saccharomyces diastaticus. The hydrolysis of starch by the E3 strain showed the release of considerable amount of reducing sugar, along with the reduction in iodine staining capacity. The product of action of glucoamylase, glucose was determined by thin-layer chromatography. The enzyme activity was found to be stable in broad pH range of $5.0{\sim}7.0$ with optimal activity at pH $5.0{\sim}6.0$. The enzyme showed optimal antivity at $50^{\circ}C{\sim}60^{\circ}C$. Soluble starch and glucose were better carbon sources for the enzyme production than xylose and glycerol. $Na^+\;and\;Mg^{2+}$ increased the glucoamylase activity, however $Hg^{2+}\;and\;Ag^{2+}$ inhibited the activity. Soluble starch was the best substrate for the enzyme activity.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.189-194
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• 2003

Rice seeds of 4 cultivars including Whachung-giant embryonic rice and Nampung-giant embryonic rice, as a group of the non-waxy rice cultivars, and Shinsunchal-giant embryonic rice and Whachungchal-giant embryonic rice, as that of the waxy rice cultivars, were germinated at $27^{\circ}C$ for 3 days to compare the changes in some physicochemical properties of the starch granules and the starch-hydrolysing enzyme activities during germination, respectively. ${\alpha}-Amylase$ activity of rices germinated for 3 days found to be higher than that of malt. Especially, Whachung-giant embryonic rice and Shinsunchal-giant embryonic rice were greater in activity than other rice cultivars and possessed the activities double that of malt. In contrast, ${\beta}-amylase$ of germinated rice found to be considerably less active than malt, although the giant embryonic rice group showed prevalent activity as compared o the normal rice group. With the starch granules, the amount of long glucose chains from amylose molecules were reduced in the non-waxy type giant embryonic rices, while the chain length increase was found in the waxy type giant embryonic rices. For the distribution profile of the glucose chain length from amylopectin molecules, we could observed that the chain length with DP (degree of polymerization) ranged 33 to 66 and 14 to 32 increased with the decreasing rate of that above 67 and below 13 regardless of starch waxiness. With non-waxy type of giant embryonic rices, susceptibility for glucoamylase were found to reduce along with germination, however, increase in susceptibility was observed with waxy rice types. In addition, we found the reduction in both initiation and termination temperature, and enthalpy for gelatinization.

• Microbiology and Biotechnology Letters
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• v.16 no.5
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• pp.348-351
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• 1988

The production of extracellular $\alpha$-amylase by Bacillus thuringiensis 19 serotypes was examined by the hydrolysis test of starch. Thirteen serotypes produced the amylase. B. thuringiensis serovar thuringiensis alesti, kurstaki, sotto, kenya, israelensis, morrisoni, entomocidus, tolworthi, thompsoni, toumanoffi, pakistani, and indiana produced tee enzyme. The amylase produced by B. thuringiensis serovar israelensis showed highest activity around pH 6.7 to 7.2 and 55$^{\circ}C$ to $65^{\circ}C$. The high production medium of the amylase was composed of 1% bactopeptone, 0.3% beef-extract, 0.3% yeast ex-tract, 0.5% NaCl, 0.3% $K_2$HPO$_4$, 0.1% KH$_2$PO$_4$, 0.2% Soluble Starch, 0.012% CaCl$_2$.2$H_2O$$_2$, 0.005% MnCl$_2$, and 0.03% MgCl$_2$.7$H_2O$. The highest production of the enzyme was observed at 4 hours culture in the soluble starch (0.6 units/$m\ell$) or glucose (0.43 units/$m\ell$) substrate.