• KSBB Journal
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• v.11 no.6
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• pp.718-725
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• 1996

Old newsprint was deinked with endoglucanase, exoglucanase and their various compositions from Trichoderma viride. The yield decreased with an increase in enzyme concentration. Especially, it was the lowest in the treatment of endo-exo mixture(1:1). It may be regarded as a synergistic actions of the cellulase components. The brightness was the highest in pulp deinked with endo-exo mixture(1:1). Maximum brightness was observed when 0.5mg/mL of the endo-exo mixture was used. The physical strength increased with increasing concentration in exoglucanase. But, it decrease with increasing concentration in endoglucanse and endo-exo mixture(1:1). Also, we investigated the yield, brightness and physical strength of endoglucanase in combination with exoclucanase(12:1, 8:1, 4:l, 1:1, 1:4, 1:8, 1:12). Maximal deinking conditions, obtained at a specific optimal ratio of endoglucanase to exoglucanse are as follow ; 12:1 for yield, 12:1 for brightness, 4:1 for tensile strength, 12:1 for bursting strength, and 8:1 for tearing strength. These results indicated that the deinking depended largely upon the action of endoglucanase. Exoglucanase was occupying more than 60% of the total crude cellulase contents. Therefore, the most effective deinking must repress the action of exoglucanase.

• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.1064-1071
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• 2022

Arabinogalactans have diverse biological properties and can be used as pharmaceutical agents. Most arabinogalactans are composed of β-(1→3)-galactan, so it is particularly important to identify β-1,3-galactanases that can selectively degrade them. In this study, a novel exo-β-1,3-galactanase, named PoGal3, was screened from Penicillium oxalicum sp. 68, and hetero-expressed in P. pastoris GS115 as a soluble protein. PoGal3 belongs to glycoside hydrolase family 43 (GH43) and has a 1,356-bp gene length that encodes 451 amino acids residues. To study the enzymatic properties and substrate selectivity of PoGal3, β-1,3-galactan (AG-P-I) from larch wood arabinogalactan (LWAG) was prepared and characterized by HPLC and NMR. Using AG-P-I as substrate, purified PoGal3 exhibited an optimal pH of 5.0 and temperature of 40℃. We also discovered that Zn²⁺ had the strongest promoting effect on enzyme activity, increasing it by 28.6%. Substrate specificity suggests that PoGal3 functions as an exo-β-1,3-galactanase, with its greatest catalytic activity observed on AG-P-I. Hydrolytic products of AG-P-I are mainly composed of galactose and β-1,6-galactobiose. In addition, PoGal3 can catalyze hydrolysis of LWAG to produce galacto-oligomers. PoGal3 is the first enzyme identified as an exo-β-1,3-galactanase that can be used in building glycan blocks of crucial glycoconjugates to assess their biological functions.

• Applied Biological Chemistry
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• v.30 no.2
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• pp.169-178
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• 1987

The extracellular and intracellular inulases from Kluyveromyces marxianus were purified and characterized. The maximum production of both inulases was achieved at stationary phase in a pH-controlled medium at pH 5 with yeast nitrogen base as organic nitrogen source. Each enzyme was concentrated by tannic acid precipitation and separated into two fractions by DEAF-cellulose chromatography. Electrophoretic analysis showed that the four fractions had three glycoprotein bards each. Only main glycoprotein band, however, had both inulase and invertase activities. There were no significant differences between two enzymes in the optimum pH and temperature. But the intracellular inulases had higher heat stability and less affinity toward inulin than the extracellular enzymes do. All the purified enzymes were considered to be exo-inulases using hydrolyzate analysis with TLC.

• The Korean Journal of Mycology
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• v.11 no.1
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• pp.15-21
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• 1983

Exodextranase from Aspergillus ustus was purified by chromatography and characterized by various conditions. The optimal pH of the purified dextranase was 6.5 and this enzyme was maximally activated at $40^{\circ}C$. The enzyme was stable at the temperature below $50^{\circ}C$. The enzyme was markedly inactivated by $Hg^{2+},\;Cu^{2+},\;KCN\;and\;Co^{2+},\;but\;Ba^{2+},\;Fe^{2+},$ cysteine, EDTA, and ascorbic acid enhanced the activity of the enzyme. The main products from the hydrolysis of dextran incubated with the dextranase were glucose, isomaltotriose and oligosaccharide. When dextran was incubated with the mixture of pullulanase and ${\alpha}-amylase$, it was hydrolyzed into glucose, isomaltose and oligosaccharide. Polysaccharides in the decade teeth powder were hydrolyzed by the dextranase into glucose, isomaltotriose and oligosaccharides. In the hydrolysis of the teeth powder with the mixture of dextranase, pullulanase and ${\alpha}-amylase$, were proved to be similar to the dextran hydrolysates.

• The Korean Journal of Mycology
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• v.26 no.2 s.85
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• pp.281-286
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• 1998

Ganoderma lucidum produced the potent pectolytic enzymes for clarifying cloudy fruit juice. Among the purified polygalacturonases (endo- and exo-polygalacturonase), endo-polygalacturonase had a good effect on juice clarification. The optimum temperature and concentration of endo-polygalacturonase for the juice clarification were $40^{\circ}C$ and 4 unit/5 ml juice, respectively. The apple juice was almost completely clarified at $40^{\circ}C$ for 60 min. It was suggested that culture filtrate of Ganoderma lucidum or it's ammonium sulfate fraction should be used as a good source of pectolytic enzyme for juice clarification.

• Journal of Microbiology and Biotechnology
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• v.9 no.1
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• pp.1-8
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• 1999

Most carbohydrates exist in nature in an insoluble state, which reduces their susceptibility towards various carbohydrases. Accordingly, they require intensive pretreatment for structural modification to enhance an enzyme reaction. The direct conversion of insoluble carbohydrates has distinct advantages for special types of reaction, especially exo-type carbohydrase; however, its application is limited due to structural constraints. This paper introduces two novel heterogeneous enzyme reaction systems for direct conversion of insoluble carbohydrates; one is an attrition coupled enzyme reaction system containing attrition-milling media for enhancing the enzyme reaction, and the other is a heterogeneous enzyme reaction system using extruded starch as an insoluble substrate. The direct conversion of typically insoluble carbohydrates, including cellulose, starch, and chitin with their corresponding carbohydrases, including cellulase, amylase, chitinase, and cyclodextrin glucanotransferase, was carried out using two proposed enzyme reaction systems. The conceptual features of the systems, their reaction characteristics and mechanism, and the industrial applications of the various carbohydrates are analyzed in this review.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.68-73
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• 1999

In order to overcome same disadvantages of acidic solubilization of pectin from apple pomace, enzymatic selective solubilization with exo-polygalacturonase was developed. According to analyses of the effects of temperature, pH and reaction time on extraction yield, the maximum yield by the enzymatic method, shown under the extraction condition of $45^{\circ}C$, pH 7 and 60 hours, was 31.0%, whereas the yield from an acidic method was 8%. Also the quality of pectin extracted by the enzymatic method was to that from acidic solubilization. The purity and methoxyl content of enzyme-extracted pectin were 80.1% and 6.36%, respectively, which were higher than 75.7% and 2.44% of acid-solubilized pectin. Viscosity average molecular weights of enzymic extracted and acid solubilized pectins were $1.50{\times}10^4\;and\;7.66{\times}10^4$, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.542-550
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• 1996

An experiment with alfalfa (Medicago sativa L.) plants was designed to investigate the changes in non-structural carbohydrate (NSC) contents and the activities of amylolytic enzymes during a regrowth period following defoliation. Sampling from hydroponic grown-plants were carried out at intervals during 24 days of regrowth. Shoot regrowth was very slow during the first 10 days and root growth was depressed after defoliation. Defoliation induced a great decrease in both total sugar and starch contents in taproots during the first 10∼14 days. A major recovery of NSC occurred from day 15. Averaged over sampling dates, the activity of exo-amylase was about 400-fold higher than that of endo-amylase. Exo-amylase activity in defoliate plants slightly increased until day 6 (maximum level) and then decreased. Endo-amylase rapidly increased for the first 4 days after defoliation and slightly increased afterwards to a maximum on day 24. These results showed that increase in amylolytic enzyme activity in taproots coincided with the time of starch utilization during regrowth and that indicated it plays an important role in starch degradation.

• 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.29 no.2
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• pp.235-243
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• 2019

A special eosinophilic agarase exo-type ${\beta}$-agarase gene, AgaDL6, was cloned from a marine agar-degrading bacterium, Flammeovirga sp. HQM9. The gene comprised 1,383-bp nucleotides encoding a putative agarase AgaDL6 of 461 amino acids with a calculated molecular mass of 52.8 kDa. Sequence analysis revealed a ${\beta}$-agarase domain that belongs to the glycoside hydrolase family (GH) 16 and a carbohydrate-binding module (CBM_4_9) unique to agarases. AgaDL6 was heterologously expressed in Escherichia coli BL21 (DE3). Enzyme activity analysis of the purified protein showed that the optimal temperature and pH of AgaDL6 were $50^{\circ}C$ and 3.0, respectively. AgaDL6 showed thermal stability by retaining more than 98% of activity after incubation for 2 h at $50^{\circ}C$, a feature quite different from other agarases. AgaDL6 also exhibited outstanding acid stability, retaining 100% of activity after incubation for 24 h at pH 2.0 to 5.0, a property distinct from other agarases. This is the first agarase characterized to have such high acid stability. In addition, we observed no obvious stimulation or inhibition of AgaDL6 in the presence of various metal ions and denaturants. AgaDL6 is an exo-type ${\beta}$-1,4 agarase that cleaved agarose into neoagarotetraose and neoagarohexaose as the final products. These characteristics make AgaDL6 a potentially valuable enzyme in the cosmetic, food, and pharmaceutical industries.