• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.366-374
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• 2017

This study investigates enzyme stabilization in clay-rock bricks through mechanical tests and image processing. Appropriate soil mixtures were designed using clay/crushed rock with ratios of 70/30, 60/40, 50/50, 40/60, and 30/70 by weight to verify the strength of the enzyme brick and soil compaction. The maximum compressive and flexural strengths in the 60/40 ratio mixture were found to be 5MPa and 1.25MPa, respectively; however, the maximum dry unit weight of $2.073g/cm^3$ was found in the 50/50 clay/gravel ratio mixture. Generally, the strength of the enzyme brick was improved by 27%. The paper concludes that in order to achieve optimal strength, soils should be mixed with the 60/40 clay/gravel ratio, which provides an adequate strength, while 50/50 ratio should be used for achieving more compaction. The SEM-EDX observation and Matlab image processing verified how the bond structure appeared after enzyme stabilization. It was found that enzymes created bond with the clay soil and the crushed rock for rendering strength and stability.

• Journal of the Korean Wood Science and Technology
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• v.29 no.3
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• pp.112-122
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• 2001

Laccase enzymes from Cerrena unicolor and Trametes versicolor were immobilized on the activated glass beads (CPG), silica gel (SG) and soil (SL). The heterogeneous matrices were activated by ${\gamma}$-aminopropyltriethoxysilane (APTES) and glutaraldehyde (GA), and their surfaces were coated by keratin (KER) on activated or non-activated CPG, SG and SL. The laccase activities were tested in the aqueous solution for the native and immobilized preparations using different pH and temperature conditions. By keratin coating on supports, in the cases of CPG-KER and SL-KER, the immobilization yield was increased from about 80% to 90%. Moreover, much less protein was immobilized in keratin coated matrices than in inorganic ones alone (e.g. on CPG-KER 57.6%, whereas on CPG alone 80.6%). Laccase immobilization on keratin coated inorganic matrices was generally more effective than that of non-coated matrices. Concerned to pH dependency, the optima pH for immobilized laccases generally shifted towards to higher values, 5.5-5.8 and even 5.9 in the case of keratin for C. unicolor and from 5.3 to 5.7 for T. versicolor, respectively, and decreased less gradually both in acidic and alkaline regions. The immobilized laccase was more stable against thermal denaturation. This seems particularly true at $75^{\circ}C$ in the case of C. unicolor, where the activity of immobilized enzyme is > 50% higher than that of the free enzyme. For T. versicolor the respective values were $65^{\circ}C$, and 50%.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.1
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• pp.34-40
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• 2003

This study was carried out to select the useful bacteria which secret extracellula enzymes for enzymatic deinking agent of old newspaper. CMCase, FPase and xylanase activities of the bacteria liquid culture were measured at optimal growth conditions. Clear zone test was checked on the solid culture. The results of this study were as follow: Eight strains of 28 bacteria isolated from a paper mill soil ground were shown strong CMCase and xylanase activity with the clear zone test. The optimal pH and temperature for culture growth were 6~8 and 26~$34^{\circ}C$, respectively and optimal culture period were less than 60 hours. Based on CMCase, FPase and xylanase activity, strain No. 18, 21, 22 and 28 which were relatively higher than the other strains, were selected for further enzymatic deinking research.

• Microbiology and Biotechnology Letters
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• v.19 no.2
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• pp.109-115
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• 1991

Twenty-five fungal strains producing an extracellular soybean milk clotting enzyme were isolated from 146 soil samples, and identified as 11 species belonging to six genera of Aspergillus oryzae (5 strains), Aspergillus flavus (2 strains), Aspergillus parasiticus (1 strain), Aspergillus tamarii (2 strains), Aspergillus niger (4 strains), Aspergillus fumigatus (2 strains), Mucor hiemalis (2 strains), Wallemia sebi (4 strains), Scopulariopsis condida (1 strain), Fusarium redolens(1 strain) and Verticillum lecanii (1 strain). Among them, Aspergillus oryzae 020 and Aspergillus tamarii 287 showed relatively high soybean milk clotting activity. The coagulabilities of the enzyme from representative strains of those species decreased as the pH of soybean milk increased from 6.0 to 7.0 The optimum temperature for soybean milk clotting enzymes of those strains were 65$^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• v.8 no.1
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• pp.49-52
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• 1998

A fungal strain able to produce filter paper activity (FPase) was isolated from soil by testing the ability to hydrolyze using filter paper. The isolated strain was identified as an Aspergilus sp. judging from its morphological and microscopical characteristics. The cellulase-xylanase system of Aspergillus sp. 8-17 was detected in situ after gel electrophoresis in the presence of SDS and showed that each protein pattern had a distinct polypeptide composition. ${\beta}$-1,4-Glucanase, cellobiohydrolase, and xylanase activity profiles differ from protein patterns. The Aspergillus sp. 8-17 hydrolytic enzymes responsible for the hydrolysis of ${\beta}$-glucan, MUC, and xylan have multiple active forms.

• Microbiology and Biotechnology Letters
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• v.25 no.2
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• pp.151-158
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• 1997

For the production of potent chitinolytic enzyme from bacteria, screening was carried out. Of 100 samples from soil, fresh water and sea water collected from the Kyung-gi area, 7 strains of chitinolytic bacteria were isolated. Among them, Aeromonas hydrophila 5-3K showed the highest chitinolytic activity. Culture conditions of Aeromonas hydrophila for the production of chitinolytic enzyme were inverstigated and lytic enzyme was fractionated by the use of ammonium sulfate and Sephadex G-100. Maximum production of chitinolytic enzyme was obtained at pH 7.0 and 30$\circ$C with chitin concentration between 0.2% and 1.0%. Conditions for the enzyme production were optimized including fermentor cultivation. The chitinolytic system of Aeromonas hydrophila 5-3K was composed of two enzymes, chitinase and chitobiase.

• Microbiology and Biotechnology Letters
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• v.17 no.2
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• pp.109-114
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• 1989

Seventeen bacterial strains producing an extracellular soybean milk clotting enzyme were Isolated from 150 soil samples, and identified as Bacillus cereus(8 strains), Bacillus pumilus(8 strains) and Bacillus licheniformis (1 strain). Among them, Bacillus pumilus strain 118 and Bacillus licheniformis strain 192 showed relatively high soybean milk clotting activity. The coagulability of enzymes from these strains decreased as the pH of soybean milk was increased from 6.0 to 7.0. The optimum temperature for soybean milk clotting activity was $65^{\circ}C$.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.332.2-333
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• 2002

Three alkaline proteases. designated JB-1. JB-2, and JB-3, are extracellular enzymes produced by Bacillus spp. JB411 which was isolated korean soil. They were separated by DEAE-sepharose CL-6B gel. and further purified using ammonium sulfate precipitation. ultra membrane filtration. and Ultrogel AcA gel filtration. The optimun pH values of proteases IB-1. JB-2. and JB-3. were shown to be 9.5. 9.5 and 7.5. respectively. All three proteases were stable in the pH range of 5-11. (omitted)

• Journal of Food Hygiene and Safety
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• v.9 no.4
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• pp.205-211
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• 1994

From 120 soil and activated sludge, the strains able to grow on benzoate and m-Toluate have been isolated after selective enrichment which were later identified as Psudomonas sp. according to its morphological and biochemical characteristics. Ben-2 strain contained two plasmid DNA having about 120 Kb and below 2.0 Kb by agarose gel electrophoresis. Form the comparative investigation of catechol 1,2-oxygenase and catechol 2,3-oxygenase activities in Ben-2 strain and its cured strain, Ben-2 strain has both of these two enzymes while cured strain has catechol 1,2-oxygenase only.

• Mycobiology
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• v.31 no.4
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• pp.209-213
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• 2003

Aspergillus flavus K-03 isolated from poultry forming soil in Korea was studied for its ability to produce extracellular proteases on basal medium containing 2%(w/v) chicken feathers. The fungus was observed to be a potent producer of such enzymes. Keratinolytic enzyme secretion was the best at 15 days of incubation period at pH 9 and temperature $40^{\circ}C$. No relationship existed between the enzyme yield and increase of biomass. Enzyme production was suppressed by exogenous sugars in descending order arabinose>maltose>mannose>fructose. But glucose did not influence the enzyme activity. The keratinolytic enzyme released by the fungus demonstrated the ability to decompose keratin substrates as chicken feather when exogenous glucose was present. The keratinolytic activity was inhibited by $HgCl_2$ and serine-protease inhibitors such as phenymethylsulfonyl fluoride(100%), chymostain(88%), crystalline soybean trypsin inhibtor(80%), antipain(45%) and aprotinin(40%), and was not by cystein-protease and aspartyl-protease inhibitors. The enzyme activity is only partially inhibited by metallo-protease inhibitor. Thus, the enzyme secreted by A. flavus K-03 belongs to the alkaline serine-type protease.