• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.324-332
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• 1985

Aspergillus niger B-15 with strong Endo-polygalacturonase (Endo-PG) activities was selected out from a total of 1,573 fungal strains isolated from various testing materials. A mutant strain, U-46, was obtained from the Aspergillus niger B-15 by repeated irradition of ultra-violet light. The objectives of the study were to investigate the fungal properties of the parental and mutant strains obtained and to study the condition of enzyme production and reaction. The results obtained are summarized as follows: 1. The size of conidial head of the U-46 mutant was smaller than that of the parental strains, B-15 and the length of the conidiophore was also shorter than that of the parental strains. 2. The optimum conditions for the Endo-PG production of the parental B-15 strain in the wheat bran Koji were obtained when 40% of water was added to the wheat bran and the temperature was 30 to $35^{\circ}C$. However, the best condition for the mutant U-46 strain was attained when 60 to 70% of water was added and the temperature was $35^{\circ}C$. The optimum growing periods were two to three days for both parental and mutant strains. 3. Under the optimum producing conditions of each strains, the enzymatic activity of the mutant U-46 was 20 times higher than the Endo-PG of the parental strain, B-15. 4. When both strains were cultured in the wheat bran Koji containing 60% of water at $35^{\circ}C$ for three days, the mutant strain. U-46, was about 46 times higher in the Endo-PG activity and about 18 times greater in Exo-PG activity than the parental strain, B-15. The activities of cellulase, $\alpha$-amylase, and glucoamylase were also highly increased in the mutant strain. 5. The mutant strain, U-46, increased its Endo-PG activity up to 20% over that of ordinary case when 1.2 to 1.5% of ammonium sulphate was added to the wheat bran. 6. The optimum condition for Endo-PG activity of crude enzyme of the mutant strain, U-46, was attained when pH of reaction solution was 4.0 to 4.5 and the temperature was $50^{\circ}C$.

• The Korean Journal of Mycology
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• v.22 no.4
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• pp.286-297
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• 1994

The optimum nutritional and cultural conditions of polygalacturonase by Ganoderma lucidum in liquid culture were studied. The optimal temperature, pH, and the duration of culture for production of the enzyme was $30^{\circ}C$, 5.5 and 14 days, respectively. The maximal production of the enzyme was obtained in a synthetic medium containing 10 g of pectin, 10 g of soluble starch, 1 g of yeast extract, 2 g of peptone, 1 g of phenylalanine, 2 g of $KH_2PO_4$, 0.2 g of $MgSO_4{\cdot}7H_2O$, 0.05 g of $CaCI_2$ and 100 g of $thiamin{\cdot}HCI$ in 1000 ml of distilled water.

• Journal of Microbiology and Biotechnology
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• v.26 no.6
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• pp.989-998
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• 2016

Acidic endo-polygalacturonases are the major part of pectinase preparations and extensively applied in the clarification of fruits juice, vegetables extracts, and wines. However, most of the reported fungal endo-polygalacturonases are active and stable under narrow pH range and low temperatures. In this study, an acidic endo-polygalacturonase (EPG4) was purified and characterized from a mutant strain of Penicillium oxalicum. The N-terminal amino acid sequence of EPG4 (ATTCTFSGSNGAASASKSQT) was different from those of reported endo-polygalacturonases. EPG4 displayed optimal pH and temperature at 5.0 and 60-70℃ towards polygalacturonic acid (PGA), respectively, and was notably stable at pH 2.2-7.0. When tested against pectins, EPG4 showed enzyme activity over a broad acidic pH range (>15.0% activity at pH 2.2-6.0 towards citrus pectin; and >26.6% activity at pH 2.2-7.0 towards apple pectin). The K_m and V_max values were determined as 1.27 mg/ml and 5,504.6 U/mg, respectively. The enzyme hydrolyzed PGA in endo-manner, releasing oligo-galacturonates from PGA, as determined by TLC. Addition of EPG4 (3.6 U/ml) significantly reduced the viscosity (by 42.4%) and increased the light transmittance (by 29.5%) of the papaya pulp, and increased the recovery (by 24.4%) of the papaya extraction. All of these properties make the enzyme a potential application in the beverage industry.

• Korean Journal of Microbiology
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• v.21 no.2
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• pp.86-94
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• 1983

Polygalacturonase of Byssochlamys fulva was purified and characterized. Specific activity increased from 2.21 units/mg protein to 10.47 units/mg protein through $(NH_4)_2SO_4$ treatment, SephadexG-100 gel filtration, and DEAE-Sephadex ion exchange chromatography. Divalent cations, such as $Ca^{++}\;and\;Cu^{++}$, increased polygalacturonase activity greatly. Added as $10^{-3}M$ concentration, $Ca^{++}$ ion enhanced enzyme activity 9.8folds. Optimum temperature was $50^{\circ}C$ and optimum pH was 5.0. Activation energy of reaction was 8.69 Kcal/mole. Michaelis-Menten $constant(K_M)\;and\;V_{max}$ of reaction were $6.27{\times}10^{-3}mole/l\;and\;2.85{$\mu}moles/min$. Polygalacturonase of Byssochlamys fulva preferred polygalacturonic acid to pectin as substrate and was presumed as endo-type on the basis of the relationship between viscosity reduction and substrate degradation. Molecular weight of polygalacturonase was estimated as 55,000.

• 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.

• Journal of Microbiology and Biotechnology
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• v.25 no.7
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• pp.999-1006
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• 2015

The endo-polygalacturonase gene (endo-pgaA) was cloned from DNA of Aspergillus niger SC323 using the cDNA synthesized by overlapping PCR, and successfully expressed in Saccharomyces cerevisiae EBY100 through fusing the α-factor signal peptide of yeast. The fulllength cDNA consists of 1,113 bp and encodes a protein of 370 amino acids with a calculated molecular mass of 38.8 kDa. After induction by galactose for 48 h, the activity of recombinant endo-PgaA in the culture supernatant can reach up to 1,448.48 U/mg. The recombinant protein was purified to homogeneity by ammonium sulfate precipitation and gel filtration column chromatography and subsequently characterized. The optimal pH and temperature of the purified recombinant enzyme were 5.0 and 50℃, respectively. The Michaelis-Menten constant (K_m) and maximal velocity (V_max) of the enzyme for pectin were 88.54 μmol/ml and 175.44 μmol/mg/min, respectively. The enzyme activity was enhanced by Ca²⁺, Cu²⁺, and Na⁺, and strongly inhibited by Pb²⁺ and Mn²⁺. The pectin hydrolysates were mainly galacturonic acid and other oligo-galacturonates. Therefore, these characteristics suggest that the recombinant endo-PgaA may be of potential use in the food and feed industries.

• Microbiology and Biotechnology Letters
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• v.17 no.6
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• pp.580-586
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• 1989

Penicillium sp. CB-20 was selected for strong polygalacturonase activity among various strains of molds found in soil. The optimum pH for the enzyme activity was 5.0 and optimum temperature was 4$0^{\circ}C$. The enzyme was relatively stable in acidic condition and unstable by heat treatment. The activation energy, Km and V$_{max}$ for the polygalacturonase were 2.499 Kcal/mol, 2.13$\times$10$^{-2}$mol/l, and 104.17 $\mu$mol/min. The activity of polygalacturonase was inhibited by Ag$^{+}$, Cu$^{++}$, Pb$^{++}$, Fe$^{+++}$, $Ca^{++}$, Na$^+$, Mn$^{++}$. The enzyme can be inactivated by the treatment ethylenediamintetra acetic acid, 2,4-dinitrophenol and $H_2O$$_2$. The results indicate the possible involvement of histidine, chelate and terminal amino group as active site. The enzyme was endo-type polygalacturonase.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.163-167
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• 2006

Pectin was enzymatically extracted from industrial lemon pomace by using an endo-polygalacturonase from Aspergillus niger as a processing aid and compared to pectin extraction by hot hydrochloric acid. The yield of pectin was 17.6 and 20.2% with enzymatic and acidic treatments, respectively. The molecular weight distribution did not vary greatly between the samples extracted with enzyme or acid. Large differences in charge density were observed, however, when the samples were analyzed by anionic-exchange chromatography. Pectin extracted by the enzymatic treatment indicated higher charge density than that obtained by hydrochloric acid. The higher charge density could due to the presence of endogenous lemon pectinesterase, which was activated at low pH 4.5 in situ conditions during the process of enzymatic extraction, leading to low methoxylated pectin with a higher charge density.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1976.10a
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• pp.189.3-189
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• 1976

흙으로부터 분리된 곰팡이 144주와 식품공학과에 보존하고 있는 곰팡이 60주로부터 121주가 endo-polygalacturonase의 활성을 나타냈다. 그 중 효소생산이 좋은 Aspergillus sp. A-2를 선정하여 배양생산된 효소에 관하여 연구한 결과는 다음과 같다.(중략)

• Korean Journal of Food Science and Technology
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• v.52 no.6
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• pp.595-603
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• 2020

To elucidate the structure-function relationship of polysaccharides obtained from Colocasia esculenta, the immuno-stimulating polysaccharide, CE-4a was purified to homogeneity from the crude polysaccharide (CE) extracted from the corms of C. esculenta by two subsequent column chromatographies using DEAE-Sepharose FF and Sephadex G-100, and analysis of their immuno-stimulatory activities and structure were conducted. CE-4a showed an increase in anti-complementary activity in a dose-dependent fashion. The molecular mass was estimated to be 182.4 kDa, which mainly consisted of galactose (43.5%) and mannose (18.2%). Methylation analysis indicated that CE-4a comprised at least 10 different glycosyl linkages, such as terminal Galp, 3-linked Galp, and 4-linked Manp, as well as a characteristic linkage, 2,4,6-branched Manp residue. To analyze the fine structure of CE-4a, it was sequentially digested using endo-α-(1→4)-polygalacturonase, exo-α-galactosidase and endo-β-1,4-D-mannanase. These analyses suggested that CE-4a is to be a highly branched galactomannan with a (1→4)-mannan backbone and galactopyranosyl oligosaccharide side chains.