• The Korean Journal of Food And Nutrition
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• v.22 no.4
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• pp.644-649
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• 2009

This study was conducted to determine the influence of cultural conditions such as temperature, time, water content, koji-thickness and agitation on the production of saccharifying amylase by Rhizopus sp. ZB9 isolated from Korean Nuruk during the preparation of rice koji, which is used in brewing Korean rice wines, Takju and Yakju. Rice kojies were made under different cultural conditions, and the saccharifying activities of each koji were tested. The temperature range suitable for the production of saccharifying amylase was $28{\sim}36^{\circ}C$. Based on the saccharifying activity and color, 60 hours of cultivation at $28^{\circ}C$ was believed to produce the optimum results. The water contents of steamed rice suitable for the production of saccharifying amylase were 35~40%. An increase in koji-thickness induced no adverse effects on the production of saccharifying amylase, but agitation-work during cultivation had a harmful effect.

• Microbiology and Biotechnology Letters
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• v.18 no.6
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• pp.547-552
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• 1990

We have been searching microorganisms which produce highly active raw starch saccharifying enzyme and also have a good cultivation characters in submerged culture. About 170 strains of molds isolated from soil and compost were tested for their amylase productivity on plate contained 2% raw corn meal. Thirty-four strains out of 170 strains produced clearance on the plates, and were tested for their raw starch saccharifying activity. Then, 4 strains which had shown relatively high levels of saccharifying activity were selected. Among them, Strain No. 55 was found to have highest level of raw starch saccharifying activity, and selected for the further studies. In this paper, the morphological, physiological and cultural characteristics of Strain No. 55 were described. Based on the results obtained in these experiments, Strain No. 55 was identified to be a similar species to Aspergillus niger.

• The Korean Journal of Food And Nutrition
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• v.3 no.1
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• pp.57-68
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• 1990

In order to obtain the fundamental informations on cellulase of Trichoderma viride QM 9414 for its production and utilization, some physico-chemical properties of the enzyme were reviewed. When T. viride QM 9414 was cultured on wheat bran medium, filter paper-disintegrating and carboxymethyl cellulose-saccharifying activity were increased with the cell growth, and thereafter CMC-saccharifying activity was kept on almost the same leved while filter-paper disintegrating activity was decreased sharply. And B-glucosidase was formed maximally on the late stationary phase of growth. The crude cellulase of cell-free extracts was purified by (NH4)2SO4 fractionation, Sephadex-G 200 column chromatography and DEAE Sephadex A-50 column chromatography. Filter paper-disintegrating, CMC-saccharifying and B-glucosidase activity were purified 10-fold, 47-fold and 38-fold, respectively. The crude enzyme was proved to be a complex of three different enzyme proteins which were showing filter paper-disintegrating, CMC-saccharifying and B-glucosidase activity. The optimal pH of the three enzyme components was alike pH 4.0, and the optimal temperature for CMC-saccharifying, filter paper-disintegrating and B-glucosidase activity were 4$0^{\circ}C$, 45$^{\circ}C$ and 5$0^{\circ}C$ respectively. The Km and Vmax values of CMC saccharifying activity for CMC were 0.485% and 3.10, and the Km and Vmax vallues of B-glucosidase for PNPG were 0.944$\times$10-3M and 0.097, respectively. The Km and Vmax values of filter paper-disintegrating activity for Avicel were determined to be 0.09% and 0.178, respectively. B-Glucosidase activity was competitively inhibited by glucose, and the Ki value for this enzyme was 3.54$\times$10-3M, CMC saccharifying activity was found to be greatly inhibited by cellobiose.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.3
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• pp.417-421
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• 1997

Quality of Sikhe, the Korean conventional rice beverage depended on the characteristics of saccharifying activities of various amylases, intrinsic flavour, budding rate and so on. To improve the quality of Sikhe, characteristics of malt produced with wheat, covered barley and naked barley were evaluated. The germination rate of wheat was 82%, but those of naked and covered barley were 69% and 56% for 6 days, respectively. Malt prepared from germinated grains with 1.5~2.0 times length of buds had the highest saccharifying power. when the extraction of enzyme and reducing sugar was carried out at 5$0^{\circ}C$ for 4 hr, saccarifying power and reducing sugar contents were the highest. Malt of wheat had the highest saccharifying power. Malt of naked barley had higher saccharifying power than that of covered barley. The amylase types of wheat, covered barley and naked barley were similar to $\beta$-amylase.

• Korean Journal of Agricultural Science
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• v.10 no.1
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• pp.166-185
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• 1983

Aspergillus niger IFO 8541 (NRRL 3112) was investigated through a series of UV rays and N-Methyl-N'-Nitro-N-Nitrosoguanidine (NTG) treatments to induce mutants that produce highly active raw starch saccharifying enzyme, and two mutants with strong enzymatic productivity were obtained. The mutants obtained were investigated for their fungal characters, condition of enzyme production, and other activities. Furthermore, the raw starch saccharifying enzyme was purified and the characteristics of purified enzyme were studied. The results obtained were summarized as follows; 1. The color of conidial head of UV-46 mutant obtained from UV rays treatment was changed to tan type and the gelatinated starch saccharifying enzyme productivity and the raw starch saccharifying enzyme productivity increased up to twice and 1.8 times compared to the productivities of original Aspergillus niger IFO 8541 cultured on the wheat bran, respectively. 2. The conidial head color of NG-41 mutant obtained from NTG treatment became lighter than that of parent strain. The gelatinated starch saccharifying enzyme productivity and raw starch saccharifying enzyme productivity increased about 1.8 times, and twice over the Aspergillus niger IFO 8541 parent strain cultured on wheat bran, respectively. The productivity of ${\alpha}$-amylase increased about 3 times more than the parent strain. 3. Two peaks of glucoanlylase and a peak of ${\alpha}$-amylase were obtained when enzyme solution of mutants and parent strain were passed through DEAE-Sephadex A-50 column chromatography. Glucoamylase I showed only gelatinated starch saccharifying enzyme activity. However, glucoamylase II (raw starch saccharifying enzyme) showed both raw starch saccharifying enzyme activity and gelatinated starch saccharifying enzyme activity. 4. Mutant, UV-46 was strengthened in glucoamylase II productivity and mutant NG-41 was strengthened in ${\alpha}$-amylase productivity. 5. Glucoamylase II of mutants and parent strain were appeared to have the same enzymatic properties. 6. Glucoamylase II of mutants and parent strain were recognized as simple enzyme through electrophoresis. 7. The glucoamylase II crystallized showed rhombic board type. 8. The molecular weight, isoelectric point, optimum pH, and optimum temperature of the glucoamylase II crystallized were estimated as 76,000, 3.4, 3.5 and $60^{\circ}C$, respectively.

• Applied Biological Chemistry
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• v.3
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• pp.9-15
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• 1962

1) Among 8 strains of Rhizopus and 7 of Aspergillus species investigated for their producibility of saccharifying amylase, Rhizopus delemar ND 1 and Aspergillus usamii mut. shirousamii were selected as having high saccharifying activity. 2). Since Rh. delemar ND 1 shows high saccharifying activity and slight transglucosidase activity, it likely seems suitable for the production of starch-sugar by enzymic saccharification. Asp. usamii mut. shirousamii exerts low saccharifying but moderate transglucesidase activity and is considered to be usable in producing sugar-syrup with particular flavor and taste. 3). Using the saccharogenic enzyme from Rh. delemar ND 1, a prelimimary trial was done to obtain purified glucose powders.

• Journal of the Korean Society of Food Culture
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• v.9 no.2
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• pp.143-148
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• 1994

'Nochi' is one of Korean traditional panfried rice cakes made from glutinous rice or millet and malt. The optimum conditions for the preparation of 'Nochi' were investigated. The ${\alpha}-amylase$ activity of malt was 62.5 units/g dry malt and ${\beta}-amylase$ 1.43 units/g dry malt. Reducing sugar content of 'Nochi' increased with the content of malt and saccharifying time. Both the hardness and cohesiveness of 'Nochi', measured by rheometer, were decreased with increasing the content of malt, while adhesiveness and hardness increased with saccharifying time, but cohesiveness decreased. The optimum conditions for the preparation of 'Nochi' were 8.0%(w/w) of malt and 1 hour 45 minutes of saccharifying time.

• Microbiology and Biotechnology Letters
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• v.15 no.6
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• pp.408-413
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• 1987

Microorganisms capable of degrading the raw naked barley were isolated from soil, and the amylase productivity of each strain was examined on plate contained 2％ raw naked barley. Of the fungi and actinomycetes tested, 71 strains were subjected to subsequent testing for amylase production, and 4 strains were selected as potent amylase producers. Among them, Strain No. 281 produced the most potent raw naked barley saccharifying enzyme, and was identified as genus Rhizopus from morphological and physiological studies. The ratio of raw starch saccharifying activity (RDA) of the crude enzyme derived from the Rhizopus sp. No. 281 was showed 2-3 fold higher than that of commercial enzyme when the raw naked barley was used as the substrate. In the case of uncooked alcohol fermentation using Rhizopus sp. No. 281 glucoamylase preparation, the alcohol yield of the broth was 2％ higher than that of the commercial enzyme.

• Applied Biological Chemistry
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• v.2
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• pp.17-21
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• 1961

The manufacture of riboflavine fortified Dwen-Jang has been tried with an exceedingly riboflavine productive Aspergillus oryzae #612 mutant which has been developed by the authors. Both the rice and barley koji of this mutant and Aspergillus sojae have been prepared. Their riboflavine production, saccharifying and protease activities have begin compared The riboflavine fortified Dwen-Jang has been manufactured using the barley koji of riboflavine productive mutant. Their riboflavine content and qualities have been studied comparing with an ordinary Dwen-Jang which has been prepared with the barley kojo of A. sojae strain. The following results have been obtained. (1) The baley koji was superior in riboflavine production and protease activity, inferior in saccharifying ability than rice koji both with A. oryzae #612 and A. sojae. (2) In barley koji, the mutant, A. oryzae #612, produces 1.5 times riboflavine than A. sojae and shows stronger saccharifying and protease activities than the latter. (3) The riboflavine fortified Dwen-Jaug manufactured contained $5.2{\gamma}/g$ of riboflavine, about 1.5 times that of A. sojae. The higher contents of free sugar and free amjno nitrogen have been observed than the ordinary Dwen-Jang manufactured with A. sojae.

• Microbiology and Biotechnology Letters
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• v.19 no.2
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• pp.140-146
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• 1991

Mutation experiments were performed to select the mutant of Aspergillus niger 55, which had lost almost all the ability to produce transglucosidases but retained that of high productivity of raw meal saccharifying enzyme, by means of successive induction with N-methyl-N'-nitro-N-nitrosoguanidine(MNNG), ultraviolet(UV) light, and ${\gamma}$-rays. Also, we used the mutant enrichment techniques, such as liquid culture-filtration procedure and differential heat sensitivity of conidia, in order to increase the possibility of obtaining a mutant. The glucoamylase productivity of mutant PFST-38 was 11 times higher than that of the parent strain. The mutant PFST-38 was morphologically identical to the parent strain, except for the size of conidia, the tendency to form conidia and the lenght of conidiophore. Asp. niger mutant PFST-38 apeared to be useful for the submerged production of the raw corn meal saccharifying enzyme.