• Journal of Microbiology and Biotechnology
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• v.33 no.4
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• pp.533-542
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• 2023

Exo-polygalacturonase (exo-PG) hydrolyzes pectin acids and liberates mono-galacturonate, which plays an important role in juice extraction, and has rarely been reported. Exo-PG (AfumExoPG28A) from Aspergillus fumigatus belongs to the glycoside hydrolase 28 family. In this study, its gene was cloned and the protein was expressed and secreted in Pichia pastoris with a maximal activity of 4.44 U/ml. The optimal temperature and pH of AfumExoPG28A were 55℃ and 4.0, respectively. The enzyme exhibited activity over almost the entire acidic pH range (>20.0% activity at pH 2.5-6.5) and remained stable at pH 2.5-10.0 for 24 h. The K_m and V_max values of AfumExoPG28A were calculated by the substrate of polygalacturonic acid as 25.4 mg/ml and 23.6 U/mg, respectively. Addition of AfumExoPG28A (0.8 U/mg) increased the light transmittance and juice yield of plantain pulp by 11.7% and 9%, respectively. Combining AfumExoPG28A (0.8 U/mg) with an endo-PG (0.8 U/mg) from our laboratory, the enzymes increased the light transmittance and juice yield of plantain pulp by 45.7% and 10%, respectively. Thus, the enzyme's potential value in juice production was revealed by the remarkable acidic properties and catalytic activity in fruit pulp.

• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.52-56
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• 1991

Inulin degradation was examined using patially puriiied enzyme mixtures of the Exo-inulinase from a Bacillus spp. and the Endo-inulinase from a Pseudomonas spp.. The highest synergistic xtion of the two cnzymcs was observcd when the Exo- and the Endo-inulinase werc mixed at the ratio of 1 to 13, and the rate of hydrolysis of the above process was enhanced approximately 1.6 times I1ight.1- than that of the reaction catalysed with a single enzyme of the same units. The enzymc mixture showed the maximal activity at pH 6.0 and $55^{\circ}C$, and in the prescncc of 0.5 mM each of $CO^{2+}$ and $Mn^{2+}$. Under the optimal condition described above fructosu was accumulated with the overitll concentration of 84% after 36 hours of the reiiction.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.3-13
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• 2020

Pseudomonas aeruginosa is a ubiquitous gram-negative bacterium causing serious infections. The P. aeruginosa T3SS is a syringe-like apparatus on the bacterial surface, with 4 effector toxins: ExoS, ExoT, ExoY, and ExoU. Here, we investigated the effect of ExoS and ExoT of the T3SS of P. aeruginosa K strain (PAK). 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 screening the inhibitors with regard to ExoS secretion, we developed the sandwich-type enzyme-linked immunosorbent assay (ELISA) system. PAK clinical strains induce proinflammatory cytokine production through the T3SS, and this involves NF-κB activation in pneumonia mouse models. We tried to confirm the role of the NF-κB transcription factor in ExoS- and ExoT-induced pneumonia mouse models. pro-inflammatory cytokines induction in response to ExoS and ExoT infection relied on NF-κB activation. Our findings highlight the roles of natural poduct in inhibiting proinflammatory cytokine expression during ExoS and ExoT exposure in PAK infections, paving the way for a novel therapeutic approach for the treatment of pulmonary infections.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.3
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• pp.340-348
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• 1993

Cross-synergistic interactions were evaluated with purified enzymes from Trichoderma viride and Penicillium funiculosum cellulase. Different synergistic patterns between enzyme components were observed. Exo-exo type synergism was found to be the most effective for degrading Avicel in all cases. Exo-endo type synergism was found to be slightly less effective. Extended hydrolysis of Avicel was carried out using mixtures of purified enzyme components with the crude cellulase from a different source. Addition of $\beta$-glucosidase from P. funiculosum cellulase to T. viride cellulase provided the great enhancement of Avicel hydrolysis. In addition, exoglucanase from T. viride cellulase was found to enhance P. funiculosum cellulase in degradation of Avicel. In conclusion, it was possible to enhance the hydrolysis of Avicel by altering the proportions of enzyme components by supplementing enzyme components from a different source. Different types of synergisms acted together to achieve maximum conversion.

• The Korean Journal of Mycology
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• v.22 no.4
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• pp.298-308
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• 1994

The properties of polygalacturonase by Ganoderma lucidum in liquid culture were investigated. The enzyme was composed of an endo- and an exo-polygalacturonase. The endo- and exo-polygalacturonase were purified approximately 56 and 9.2-fold, respectively, through ammonium sulfate fractionation, gel filtration on Biogel P-100, anion exchange chromatography on DEAE-cellulose, gel chromatography on Sephadex G-150 and re-gel chromatography on Sephadex G-150. The endo- and exo-polygalacturonase had higher affinity for apple pectin than for citrus pectin or pectic acid. The Km values of the endo- and exo-polygalacturonase for apple pectin, determined on the Lineweaver-Burk plot, were 1.44 and 10.6 mg $ml^{-1}$ for apple pectin, respectively. Purified endo-polygalacturonase was found to be homogeneous electrophoretically and had a molecular weight of 54,000 estimated on SDS polyacrylamide gel. The optimal pH for the activity of the enzymes was 4.0. The endo- and exo-polygalacturonase were stable in the pH range of 4.0 to 6.0 and 3.5 to 5.5, respectively. The optimal temperatures of the endo- and exo-polygalacturonase were 40 and $60^{\circ}C$, respectively. The exo-polygalacturonase was more resistant to heat than the endo-polygalacturonase, requiring heating for 40 min at $80^{\circ}C$ for complete inactivation. The activity of the endo-polygalacturonase was increased by $Ca^{++}$ and $Mn^{++}\;ions$, while that of the exo-polygalacturonase was increased by $Ca^{++}\;ion$ only, and was not affected by $Mn^{++}\;ion$.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.1
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• pp.24-29
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• 2004

Alkaline cellulolytic enzymes from cultured medium of Coprinus cinereus 2249 were purified with gel and ion-exchange chromatography and characteristics of those enzyme proteins were investigated. A fiber length distribution and a crystallinity of cellulose and sugar composition of enzyme treated Mixed Office Wastepaper(MOW) and Unbleached Kraft Pulp(UKP) were analysed. The conclusion could summarized as follows; \circled1 Alkaline and acidic, endo- and exo-glucanases were purified from cultured medium of Coprinus cinereus 2249. \circled2 The approximate molecular weight of alkaline endo-glucanase was 42 kDa, and also that of alkaline exo-glucanase was 50 kDa. A fiber length distribution and a crystallization of cellulose and sugar composition of enzyme treated MOW and UKP were not so much changed with original paper and pulp.

• Korean Journal of Microbiology
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• v.40 no.3
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• pp.230-231
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• 2004

The mycelia of Sparassis crispa DSMZ 5201 were cultivated at $24^{\circ}C$ for 15 days in yeast-malt extract-glucose broth (pH 4.0) and the filtrate was used as crude enzyme solution to determined the extracellular enzyme activity. The specific activity of $\alpha$-amylase was 44.27 unit/protein. The specific activities of protease, CMCase, $\beta$-glucosidase, chitinase, exo-$\beta$-l,4-glucanase were relatively high. However, a very little activity of xylanase was found.

• KSBB Journal
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• v.17 no.6
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• pp.549-554
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• 2002

The hydrolysis of old book(Hanji) was performed using endoglucanase Ⅰ(endo Ⅰ), and exoglucanase II(exe II) and their mixtures purified from Trichoderma viride cellulase. The optimum degradation of old book(Hanji) with endo Ⅰ, exo II and endo-exo mixture(Ⅰ：Ⅰ) were exhibited at pH 4.5, 5.5, 5.0, respectively. Maximum degradations using endo Ⅰ, exo II and endo-exo mixture(Ⅰ：Ⅰ) occurred at 50$\^{C}$. The yield decreased an increasing the enzyme concentration. Especially, the yield was lowest for treatment with the endo Ⅰ-exo II mixture(Ⅰ：Ⅰ), which may be regarded as being due to a synergistic action of the cellulase components. Physical strength increased with increasing exo II concentration, and decreased with increasing concentration of endoglucanase Ⅰ. These results indicated that the degradation of old book(Hanji) depends largely upon the action of endoglucanase. Therefore, the most effective method of conserving paper cultural properties is to repress the action of endoglucanase.

• Journal of Microbiology and Biotechnology
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• v.13 no.2
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• pp.269-275
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• 2003

Chitosan-degrading activity induced by chitosan was founf in culture filtrate of Aspergillus flavus IAM2044. Aspergillus flavus IAM2044 had a higher level of chitosanolytic activity when chitosan was used as a carbon source, and yeast extract and peptone were supplemented as nitrogen sources. One of the chitosan-degrading enzymes was purified to homogeneity by ammonium sulfate precipitation followed by cation-exchange and gel filtration chromatographies. The enzyme was monomeric, and its molecular mass was 45 kDa. The optimum pH and temperature of the enzyme were 5.0 and $50^{\circ}C$, respectively. The activity was stable in the pH range of 3.5 to 7.0 and at a temperature below $50^{\circ}C$. Reaction products analyzed by the viscosimetric assay and thin layer chromatography clearly indicated that the enzyme was an exe-type chitosanase, $exo-{\beta}-D-glucosaminidase$, that released GlcN from the nonreducing ends of the oligosaccharide chains.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.14-19
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• 1992

The xylanase producing microorganisms occurring on rotten woods were selectively isolated on the modified Czapek-Dox medium supplemented with 0.5% xylan as a sole carbon source. Among more than three-hundred isolates of xylanase producing microorganisms, only two bacterial isolates were turned out to be more potent xylanase producer than the reference strain of xylanase producer, Aureobaszdium pullulans NRRL Y-2311. The exo-xylanase producer, bacterial isolate No. 33 was identified as a strain of Pseudomonas sp. on the basis of morphological and biochemical characterizations as well as cellular fatty acid composition. Optima of pH and of temperature for enzyme reactions of xylanase were 5.5 and $50^{\circ}C$ respectively. The enzyme was stable in a range of pH 5.0~7.0 and below $45^{\circ}C$. Among the number of carbohydrate substrates, xylose was turned out to be a potent inducer of Pseudomonas sp. No.33 exo-xylanase. Among the raw materials tested, rice straw was the best material for xylanase production by Pseudomonas sp. strain No. 33.