• The Korean Journal of Mycology
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• v.19 no.2
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• pp.143-147
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• 1991

Botryosphaeria dothidea causing apple fruit rot was cultured in pectin-polypectate mine­raI salts or apple mediumss, to investigate pectolytic enzyme production and activity. Exo-polygalactu­ronase(PG) and exo-polymethylgalacturonase (PMG) in apple medium showed maximum of activity to 6.4 and 7.2 units at six days of culture, respectively. Their maximum activity in pectin-polypectate mineral salts medium was 5.9 and 5.3 units at eight days of culture lower than in apple medium respectively. Endo-PG and endo-PMG in pecin-polypectate mineral salts medium were maximum of activity to 4.4 and 16.2 units at six and eight days of culture, respectively, but activities in apple medium were 3.2 and 6.7 units at eight days of culture. Activity of polygalacturonate-trans-­eliminase(PGTE) and pectinmethyl-trans-eliminase(PMTE) was higher in pectin-polypectate mineral salts medium than in apple medium. Fungal growth was maximum at six and eight days of culture in pectin-polypectate mineral salts and apple medium, respectively.

• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.347-355
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• 2016

An exo-β-D-glucosaminidase (AorCsxA) from Aspergillus oryzae FL402 was heterologously expressed and purified. The deduced amino acid sequence indicated that AorCsxA belonged to glycoside hydrolase family 2. AorCsxA digested colloid chitosan into glucosamine but not into chitosan oligosaccharides, demonstrating exo-β-D-glucosaminidase (CsxA) activity. AorCsxA exhibited optimal activity at pH 5.5 and 50℃; however, the enzyme expressed in Pichia pastoris (PpAorCsxA) showed much stronger thermostability at 50℃ than that expressed in Escherichia coli (EcAorCsxA), which may be related to glycosylation. AorCsxA activity was inhibited by EDTA and most of the tested metal ions. A single amino acid mutation (F769W) in AorCsxA significantly enhanced the specific activity and hydrolysis velocity as revealed by comparison of V_max and k_cat values with those of the wild-type enzyme. The three-dimensional structure suggested the tightened pocket at the active site of F769W enabled efficient substrate binding. The AorCsxA gene was heterologously expressed in P. pastoris, and one transformant was found to produce 222 U/ml activity during the high-cell-density fermentation. This AorCsxA-overexpressing P. pastoris strain is feasible for large-scale production of AorCsxA.

• Journal of the Korean Graphic Arts Communication Society
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• v.26 no.1
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• pp.65-72
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• 2008

Kappa number and brightness were more increased with treatment of endo-xylanase than hydrogen-peroxide. In pulp bleaching process, endo-xylanse was most effective in the other enzyme treatment. Exo-xylanase was effective more than 4 unit treatment. Kappa number was tiny increased with enzyme ratio, but less than 4 unit treatment, increased with hydrogen peroxide treatment ratio. In more than 4 unit acetyl-estease treatment, Kappa number and brightness were not influenced with enzyme treatment ratio, but concentration of hydrogen-peroxide.

• Journal of Life Science
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• v.22 no.6
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• pp.837-843
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• 2012

This study was carried out to investigate the morphological and physiological characteristics of six new cultivars of Hypsizygus marmoreus (Hm) and measure endo-, exo-cellular enzyme-specific activity. The domestic wild stain (Hm3-10) and commercial strain in Japan (Hm1-1) were mated by crossing monokaryon mycelia. We gained 58 strains from one of 400 crosses through the $1^{st}$ cultivation experiment, and selected six strains from one of 58 strains through the $2^{nd}$ cultivation experiment. When six of the selected new strains were grown during several spawn culture periods (60, 70, 80, 90, and 100 days), a spawn culture period of more 80 days was considered to be excellent as being shorter than 19~20 days. Therefore, we determined the period of spawn culture as 80 days. Three strains such as Hm15-3, Hm15-4, and Hm17-5 showed an excellent result. When endo-cellular enzyme activity measured eight strains, we obtained a result of that specific activity of ${\alpha}$-amylase at the highest as 73.9~102.2 unit/mg protein, and chitinase is lower than ${\alpha}$-amylase at 8.1~13.1 unit/mg protein. When exo-cellular enzyme activity measured eight strains, we determined the result of that specific activity of ${\alpha}$-amylase is the highest at 5,292~1,184 unit/mg protein, and CMCase and xylanase were 1,140~245 unit/mg protein, 94~575 unit/mg protein, compared to each other. However, the enzyme activity of ${\beta}$-glucosidase and chitinase is low.

• 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.20 no.1
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• pp.20-24
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• 1992

In order to reuse inulinase effectively, a method for immobilizing both endo- and exoinulinase to vinylsulfone activated agarose via covalent bond was investigated. The immobilized enzyme preparation had, respectively, 400 U for exoinulinase activity and 80 U for endoinu- Iinase activity per gram gel. A thermal stability by immobilization had increased in the case of exoinulinase. Optimum pHs for two immobilized enzymes were 4.4 to 5.0. Synergistic effect which depends on mixed ratio of two immobilized enzymes was the best when the mixed ratio of endo/exo lay between 0.1 and 0.5, and its activity of the mixed enzyme increased 1.7 times as compared to that of each immobilized enzyme. Inulinase activities of both of the immobilized enzymes did not change during 20 times experimental runs in a batch reactor.

• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.227-233
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• 2015

Two recombinant arabinosyl hydrolases, α-_L-arabinofuranosidase from Geobacillus sp. KCTC 3012 (GAFase) and endo-(1,5)-α-_L-arabinanase from Bacillus licheniformis DSM13 (BlABNase), were overexpressed in Escherichia coli, and their synergistic modes of action against sugar beet (branched) arabinan were investigated. Whereas GAFase hydrolyzed 35.9% of _L-arabinose residues from sugar beet (branched) arabinan, endo-action of BlABNase released only 0.5% of _L-arabinose owing to its extremely low accessibility towards branched arabinan. Interestingly, the simultaneous treatment of GAFase and BlABNase could liberate approximately 91.2% of _L-arabinose from arabinan, which was significantly higher than any single exo-enzyme treatment (35.9%) or even stepwise exo- after endo-enzyme treatment (75.5%). Based on their unique modes of action, both exo- and endo-arabinosyl hydrolases can work in concert to catalyze the hydrolysis of arabinan to _L-arabinose. At the early stage in arabinan degradation, exo-acting GAFase could remove the terminal arabinose branches to generate debranched arabinan, which could be successively hydrolyzed into arabinooligosaccharides via the endo-action of BlABNase. At the final stage, the simultaneous actions of exo- and endo-hydrolases could synergistically accelerate the _L-arabinose production with high conversion yield.

• Journal of Microbiology and Biotechnology
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• v.33 no.4
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• pp.430-440
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• 2023

The type three secretion system (T3SS) is a major virulence system of Pseudomonas aeruginosa (P. aeruginosa). The effector protein Exotoxin S (ExoS) produced by P. aeruginosa is secreted into the host cells via the T3SS. For the purpose of an experiment on inhibitors with regard to ExoS secretion, we developed a sandwich-type enzyme-linked immunosorbent assay (ELISA) system. Quercetin was selected because it has a prominent ExoS inhibition effect and also is known to have anti-inflammatory and antioxidant effects on mammalian cells. In this study, we investigated the effects of quercetin on the expression and secretion of ExoS using ELISA and Western blot analysis methods. The results showed that the secretion of ExoS was significantly decreased by 10 and 20 µM of quercetin. Also, popB, popD, pscF, and pcrV which are composed of the T3SS needle, are reduced by quercetin at the mRNA level. We also confirmed the inhibitory effect of quercetin on cytokines (IL-6, IL-1β, and IL-18) in P. aeruginosa-infected H292 cells by real-time polymerase chain reaction (PCR) and ELISA. Collectively, quercetin inhibits the secretion of ExoS by reducing both ExoS production and the expression of the needle protein of T3SS. Furthermore, these results suggest that quercetin has the potential to be used as an anti-toxic treatment for the inflammatory disease caused by P. aeruginosa infection.

• The Korean Journal of Mycology
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• v.16 no.2
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• pp.64-69
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• 1988

Isoates with changed pathogenicity were selected among iprodione-resistant Alternaria mali to investigate any relationship between their pectolytie enzyme activity and pathogenicity. In artificial medium, strongly pathogenic isolates $S_1$, and $R_3$ showed higher enzyme activity than weakly pathogenic isolate $R_8$.Activity of endo-polymethylgalacturonase and end-o-polygalacturonase was more than 3 times. But activity of pectin methylesterase and pectin Iyase by isolaste $S_1$ was higher than those by $R_3$ and $R_8$ isolates. In apple medium dialyzed against distilled water, activity of enzyme by each isolate was increased but growth of each isolate was reduced. When iprodione was added to the medium, enzyme activity and growth of isolate $S_1$, were reduced but strongly pathogenic isolate .$R_3$ among iprodione-resistant ones showed increased enzyme activity except for exo-polygalacturonase in dialyzed apple medium.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.971-976
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• 1999

Exo-polygalacturonase (EPG) from Rhizopus sp. was applied to the extraction of pectin from pear pomace because EPG produces pectin by solubilizing protopectin. The content of total galacturonic acid in water-alcohol insoluble pectin (WAIP) was determined as 34.6%. Pear pomace was solubilized by using EPG, with regarding reaction pH, temperature, time and ratio of enzyme to substrate in order to find optimum condition. While the yield by an acidic treatment was 6.2%, the maximum yield by an enzymatic treatment was 23.4% under the extraction condition of pH 7.8, $60^{\circ}C$, 36 hr and 1/10 of enzyme/substrate. At this condition, the purity and methoxyl content of enzyme-extracted pectin were, respectively, 34.7% and 0.7%, while those of acid-extracted pectin were, respectively, 71.1% and 5.0%. Meanwhile, the average molecular weight of pectin extracted by the enzymatic method was $2.5{\times}10^{3}$ while that of acid-solubilized pectin was $8.4{\times}10^{3}$.