• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.3
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• pp.238-246
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• 1984

The objective of this experiment was to improve the quality of Kochujang and to shorten the aging time of it by using the Kojis of various Aspergillus strains. During the autumn season Kochujangs were mashed with Koji of Aspergillus oryzae, Aspergillus kawachii and Aspergillus shirousamii. Chemical composition of the Kochujang was determined during the aging period. There was no significant difference in quality and component between the Kochujang made with Aspergillus oryzae cultured Koji and Aspergillus kawachii cultured Koji. But the Kochujang with Aspergillus shirousamii cultured Koji was better in flavor, color and amino nitrogen contents than the Kochujang with Aspergillus oryzae cultured Koji, though two Kochuangs were almost the same in general components. The significant difference between the two tested Kochuangs was observed in pH, and the pH of the Kochujong with Aspergillus shirousamii cultured Koji was extremely low during the aging period. Thus it is presumed that Aspergillus shirousamii Koji can be used for the improvement of quality of Kochujang if a suitable method is applied to prevent pH from lowering.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.4
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• pp.363-369
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• 2004

Three different doengjang(fermented soybean paste) were prepared by using B. subtilis SS103 with high angiotensin converting enzyme(ACE) inhibitory activity, Asp. oryzae and mixed culture of two organisms, respectively. Quality characteristics and the inhibitory activity were compared. $\beta$-Amylase activity rapidly increased during 30 days of fermentation, but lower activity was found in doenjang prepared with B. subtilis. However, $\alpha$-Galactosidase activity decreased for 15 days of fermentation and little activity was observed after that fermentation period. Protease production tended to increase during the fermentation. High protease activity was found only in doengjang prepared with Asp. oryzae, but the doengjang prepared with B. subtilis SS103 showed very low activity. Total isoflavone content at 90 day fermentation was the highest in doengjang prepared with mixture of Asp. oryzae and B. subtilis. ACE inhibitory activity increased during the fermentation period. The highest activity was found in doengjang made with mixture of Asp. oryzae and B. subtilis. Sensory evaluation on doengjang itself and its soup indicated that doengjang made with mixture of Asp. oryzae and B. subtilis showed higher acceptability on taste, flavor and color than those prepared with only Asp. oryzae or B. subtilis, respectively.

• The Plant Pathology Journal
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• v.27 no.1
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• pp.89-92
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• 2011

Cyclic AMP receptor-like protein (Clp), is known to be a global transcriptional regulator for the expression of virulence factors in Xanthomonas campestris pv. campestris (Xcc). Sequence analysis showed that Xanthomonas oryzae pv. oryzae (Xoo) contains a gene that is strongly homologous to the Xcc clp. In order to determine the role of the Clp homolog in Xoo, a marker exchange mutant of $clp_{xoo4158}$ was generated. Virulence and virulence factors, such as the production of cellulase, xylanase, and extracellular polysaccharides (EPS) and swarming motility were significantly decreased in the $clp_{xoo4158}$ mutant. Moreover, the mutation caused the strain to be more sensitive to hydrogen peroxide and to over-produce siderophores. Complementation of the mutant restored the mutation-related phenotypes. Expression of $clp_{xoo4158}$, assessed by reverse-transcription realtime PCR and clp promoter activity, was significantly reduced in the rpfB, rpfF, rpfC, and rpfG mutants. These results suggest that the clp homolog, $clp_{xoo4158}$, is involved in the control of virulence and resistance against oxidative stress, and that expression of the gene is controlled by RpfC and RpfG through a diffusible signal factor (DSF) signal in Xanthomonas oryzae pv. oryzae KACC10859.

• Applied Biological Chemistry
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• v.30 no.4
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• pp.345-350
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• 1987

Three lots of mejues were prepared with three different strains of Aspergillus oryzae, Bacillus natto, Bacillus subtilis and one was made by conventional method. The four different soy bean pastes were analyzed for compositions of free amino acids, sugars and organic acids during the period of fermentation. Amino nitrogen contents in the samples of A. oryzae were higher than others throughout the aging period. The amounts of each amino acids were varied markedly among the samples after 20-days, while glutamic acid, aspartic acid, lysine and phenylalanine were dominant in all samples after 90-days. Glucose contents were found to be in the range of $0.46{\sim}2.66%$ and other sugars of fructose, sucrose, rhamnose and maltose were less than 0.35%. The levels of total free sugar were relatively higher in the samples prepared with B. natto than others. Citric, lactic, malic, acetic and oxalic acids were identified, and the content of lactic acid was higher in the samples of A. oryzae, whereas citric acid was higher in conventional method.

• Microbiology and Biotechnology Letters
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• v.10 no.3
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• pp.227-232
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• 1982

The methods determining the growth rate of mold on beans were investigated in order to compare the growth of Aspergillus oryzae on lupinseed to that on soybean. The growth of A. oryzae on cooked whole or paste form of bean substrates was evaluated by the measurements of colony diameter and hyphae length of the mold. The mold showed characteristic lag times to form the colony on different types of substrate. The growth of colony diameter was coincided with the increase in $\alpha$-amino nitrogen content of the substrate when the moisture level of the substrates was similar each other. The colony diameter and the cultivation time after the lag period showed a straight line relationship, from which the growth rate was estimated. in general, lupinseed paste allowed faster growth of A. oryzae than soybean paste at the initial growth phase. The lag time to form the colony was 24.0 hrs on lupinseed paste and 44.4 hrs on soybean paste. The growth rate after colony formation was, however, 7.05 mm/day for lupinseed paste and 8.83mm/day for soybean paste, which indicated that the growth rate after the lag period was faster on soybean compared to lupinseed. The sporulation time of the mold was related to the lag time for the colony formation. The measurement of hyphae length on whole beans could be used as a simple and rapid method of estimating the growth property of mold on different substrates.11 showed that the growth of A. oryzae was partly hindered by the thick hull of the lupinseed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.2
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• pp.141-147
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• 2008

This study investigated the isoflavone contents and physiological properties of non-fermented soybean (NF) and the fermented soybeans prepared with Asp. oryzae (AO) and B. natto (BN). The total isoflavone contents (daidzin, genistin, daidzein and genistein) of NF, AO and BN were 81.8 mg/100 g, 130.7 mg/100 g and 139.5 mg/100 g, respectively. Especially, the total phenol contents of NF, AO and BN were 2.1%, 4.3% and 7.6%, and the total flavonoid contents were 1.3%, 1.6% and 2.7%, respectively. The nitrite-scavenging abilities of NF, AO and BN were 34.4%, 55.2% and 92.5%, respectively. Antimicrobial activity of BN was shown to be the strongest to Bacillus cereus, Staphylococcus aureus and Escherichia coli. The SOD-like activity was the strongest in AO, whereas the electron donating ability was the strongest in BN. Antioxidant activity of AO at concentration of 0.02% was stronger than BN or NF.

• Food Science and Preservation
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• v.21 no.4
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• pp.573-580
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• 2014

The enzymatic activity of Nuruk and the quality properties of Yakju were investigated according to different fungi. The fungi that were used in this study were Aspergillus kawachii KCCM 32819, Aspergillus niger KCCM 32005, Rhizopus japonicus KCCM 11604, Rhizopus oryzae KCCM 11272, Rhizopus oryzae KCCM 11273, Rhizopus oryzae KCCM 11276, and Mucor rouxii KCCM 60148. The study results are as follows. The saccharogenic power of Rhizopus oryzae KCCM 11272 Nuruk was the highest (3,647.72 SP/g) among all the samples. The ${\alpha}$-amylase production and protease activities were highest (3.76 DU and 4.7 tyrosine mg/min, respectively) in the Rhizopus japonicus KCCM 11604 Nuruk. The pH levels of the Yakju made with commercial Nuruk and Rhizopus japonicus KCCM 11604 Nuruk were 4.14 and 4.07, respectively. The total titratable acid content of the Yakju made with Rhizopus oryzae KCCM 11273 Nuruk was the highest (0.56%) among all the samples. Rhizopus japonicus KCCM 11604 and Rhizopus oryzae KCCM 11272 had the highest ethanol yields (15.18% and 15.10%, respectively). In the sensory evaluation carried out in this study, the panel preferred the Yakju made with Rhizopus japonicus KCCM 11604 Nuruk. Overall, however, the panel did not like the Yakju made with Aspergillus niger KCCM 32005 Nuruk.

• Journal of Applied Biological Chemistry
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• v.51 no.3
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• pp.95-101
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• 2008

The gene encoding a putative esterase of Xanthomonas oryzae pv. oryzae was cloned using PCR technique. The gene was expressed with His6 tag in E. coli. One-step purification of the recombinant esterase with Ni-NTA resin resulted in one band by SDS-PAGE analysis. The purified enzyme showed a molecular weight of 30 kDa, as expected, therefore the enzyme was a mononer. The enzyme was the most active toward p-nitrophenyl (p-NP) acetate and p-NP-butyrate to a lesser extent. However, the enzyme could not hydrolyze p-NP-myristate, palmitate, and stearate. Therefore, the enzyme is considered as an esterase, very different from lipase. The purified esterase had optimal pH at around 8.0 and was stable in a broad range of pH values. The optimal temperature ranged from 30 to $40^{\circ}C$, and the residual activity observed after heat treatment at $55^{\circ}C$ for 20 min was 72 % of the initial activity. The activity was inhibited by the presence of copper and cobalt ions.

• Microbiology and Biotechnology Letters
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• v.29 no.1
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• pp.12-17
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• 2001

Aspergil-lus coreanus NR-15 and Aspergilus oryzae NR-2-5 from traditional Korean Nuruk were selected as parental strains producing starch hydrolysis enzyme. Xll(Arginine-) mutant from A. coreanus NR 15-1 showed high glu-doamylase activity and total acid productivity. Z6(Adenine-) mutant from A. oryzae NR2-5 showed the highest $\alpha$-amylase activity. Therefore, both XII and Z6 mutants were selected and investigated for the optimal conditions of protoplast formation for protoplast fusion. Mixture of equal amount of cellulase and driselase(10mg/ml each) was the most effective as lytic enzymes. The optimal pH and temperature for protoplast formation were 5.0 and $30^{\circ}C$, respectively. The most effective reaction for protoplast formation time was 4 hours. The maximum of protoplst for- mation of Xll mutant and Z6 mutant were $6.54$\times$10^{7}$ protoplasts/ ml and $3.04$\times$10^{ 7}$ protoplasts/ml, and the regen-eration frequencies of the protoplasts were 11.3% and 11.6%, respectively. The size of the protoplasts from X11 and Z6 mutants were 3~6 $\mu\textrm{m}$ and 4~9$\mu\textrm{m}$, respectively.

• Korean Journal Plant Pathology
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• v.3 no.3
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• pp.168-173
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• 1987

The constancy of the patterns of esterase isozymes in the mycelium of Pyricularia oryzae grown under various cultural conditions was observed by $10\~25\%$ polycrylamide gradient slab gel. The position of the isozyme was not affected by cultural age for 24 days. However the intensity of the band was affected. The band patterns were not affected by the carbon sources (glucose, maltose, fructose, sucrose or starch), single spore isolates, successive transfer culture and regenerated isolates from protoplast cultures.