• Korean Journal of Food Science and Technology
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• v.5 no.4
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• pp.224-230
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• 1973

The culture used wheat bran as media for four kind of mold strains such as Aspergillus oryzae, Aspergillus kawachii, Aspergillus usamii and Rhizopus javanicus to examine which strain could higher the activity of amylase most which is used for alcohol fermentation. It also provided three different kind of wheat bran media containing starch of 47%, 51% and 55% respectively for each strain. For each media it also added three different kind of nitrogen sources; ammonium sulfate, casein, and ammonium sulfate and casein equally mixed. Each nitrogen source added was subordinately differentiated into three different percentages, 2%, 4% and 6% respectively, except the 2% for the ammonium sulfate. The results obtained were summarized as follows (1) The activity of ${\alpha}-amylase$ was highest in the media of starch value 47% of wheat bran with 6% of casein added. (2) The activity of ${\beta}-amylase$ was highest in the media of starch value 51% of wheat bran with 2% of the equal mixture of ammonium sulfate and casein added. (3) The activities of both ${\alpha}-amylase$ and ${\beta}-amylase$ of Aspergillus usamii were highest in the media of starch value 47% wheat bran with no addition of nitrogen source. (4) Of the four strains examined, the activities of ${\alpha}-amylase$ and ${\beta}-amylase$ cultured in Rhizopus javanicus were both relatively higher. (5) The activities of ${\alpha}-amylase$ and ${\beta}-amylase$ of the strains examined became lower as the percentage of starch contents increased except in Rhizopus javanicus.

• Mycobiology
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• v.44 no.3
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• pp.155-161
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• 2016

The most economically important species used in a wide range of fermentation industries throughout Asia belong to Aspergillus section Flavi, which are morphologically and phylogenetically indistinguishable, with a few being toxigenic and therefore a major concern. They are frequently isolated from Korean fermentation starters, such as nuruk and meju. The growing popularity of traditional Korean alcoholic beverages has led to a demand for their quality enhancement, therefore requiring selection of efficient non-toxigenic strains to assist effective fermentation. This study was performed to classify the most efficient strains of Aspergillus section Flavi isolated from various types of traditional wheat nuruk, based on a polyphasic approach involving molecular and biochemical evaluation. A total of 69 strains were isolated based on colony morphology and identified as Aspergillus oryzae/flavus based on internal transcribed spacer and calmodulin gene sequencing. Interestingly, none were toxigenic based on PCR amplification of intergenic regions of the aflatoxin cluster genes norB-cypA and the absence of aflatoxin in the culture supernatants by thin-layer chromatography analysis. Saccharification capability of the isolates, assessed through ${\alpha}-amylase$ and glucoamylase activities, revealed that two isolates, TNA24 and TNA15, showed the highest levels of activity. Although the degrees of variation in ${\alpha}-amylase$ and glucoamylase activities among the isolates were higher, there were only slight differences in acid protease activity among the isolates with two, TNA28 and TNA36, showing the highest activities. Furthermore, statistical analyses showed that ${\alpha}-amylase$ activity was positively correlated with glucoamylase activity (p < 0.001), and therefore screening for either was sufficient to predict the saccharifying capacity of the Aspergillus strain.

• Korean Journal of Poultry Science
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• v.32 no.4
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• pp.291-300
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• 2005

Two experiments were carried out to assess the appropriate incubation conditions namely; duration, moisture content and the ideal microbial inoculant for fermented dried food waste(EW) offered to broilers. The nutrient utilization of birds fed the FW diets at varying dietary inclusion rates was also compared with a control diet. In Experiment 1, different moisture contents(MC) of 30, 40, 50 and $60\%$ respectively were predetermined to establish the ideal duration of incubation and the microbial inoculant. A 1mL Aspergillus oryzae(AO) $(1.33\times10^5\;CFU/mL)$ was used as the seed inoculant in FW. This results indicated that the ideal MC for incubation was $40\~50\%$ while the normal incubation time was > 72 hours. Consequently, AO seeds at 0.25, 0.50, 0.75 and 1.00mL were inoculated in FW to determine its effect on AO count. The comparative AO count of FW incubated for 12 and 96 hours, respectively showed no significant differences among varying inoculant dosage rates. The FW inoculated with lower AO seeds at 0.10, 0.05 and 0.01mL were likewise incubated for 72 and 96 hours, respectively and no changes in AO count was detected(p<0.05). The above findings indicated that the incubation requirements for FW should be $%40\~50\%$ for 72 hours with an AO seed incoulant dosage rate of 0.10mL. Consequently, in Experiment II, after determining the appropriate processing condition for the FW, 20 five-week old male Hubbard strain were used in a digestibility experiment. The birds were divided into 4 groups with 5 pens(1 bird per pen). The dietary treatments were; Treatment 1 : Control(Basal diet), Treatment 2 : $60\%$ Basal+4$40\%$ FW, Treatment 3 : $60\%$ $Basal+20\%\;FW+20\%$ AFW(Aspergillus oryzae inoculate dried food-waste diet) and Treatment 4: $60\%$ Basal+$40\%$ Am. Digestibility of treatment 2 was lowed on common nutrients and amino acids compared with control(p<0.05) and on crude fat and phosphorus compared with AFW treatments(T3, T4)(plt;0.05). Digestibility of treatment 3 and 4 increased on crude fiber and crude ash compared treatment 2 (p<0.05). Digestibility of control was high on agrinine, leucine, and phenylalnine of essential amino acids compared with treatment 3 and 4(p<0.05), and diestibility of treatment 3 and 4 was improved on arginine, lysine, and threonine of essential amino acids. Finally, despite comparable nutrient utilization among treatments, birds fed the dietary treatment containing AO tended to superior nutrient digestion to those fed the $60\%$ Basa1+$40\%$ FW.

• Korean Journal of Food Science and Technology
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• v.40 no.1
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• pp.56-62
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• 2008

This study was carried out to investigate the changes in microflora, enzyme activity and sensory quality of four kinds of cheonggukjang during fermentation. Three different kinds of cheonggukjang were prepared with germinated soybeans using rice straw, Bacillus natto, B. natto plus Aspergillus oryzae, and the last one was prepared with non-germinated soybeans using rice straw. The pH values of cheonggukjang prepared with germinated or non-germinated soybeans increased up to 36 hr of fermentation and then decreased. The number of bacteria and molds increased significantly up to 24 hr of fermentation and then leveled off during fermentation. Acidic and neutral protease activities of all cheonggukjang continuously increased significantly during fermentation. ${\alpha}$- and ${\beta}$-Amylase activities of cheonggukjang decreased slightly during fermentation except cheonggukjang prepared with germinated soybeans using the mixed culture. The number of microflora, protease and ${\alpha}$-amylase activities were highest in cheonggukjang prepared with germinated soybeans using B. natto plus A. oryzae. The results of the sensory evaluation revealed that for overall acceptability, the cheonggukjang prepared with germinated soybeans using B. natto plus A. oryzae was similar to the cheonggukjang prepared with non-germinated soybeans using rice straw.

• Journal of Microbiology and Biotechnology
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• v.21 no.12
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• pp.1270-1279
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• 2011

Bealmijang is a short-term aged paste made from meju, which is a brick of fermented soybeans and other ingredients. Different types of bealmijang are available depending on the geographic region or ingredients used. However, no study has clarified the microbial diversity of these types. We identified 17 and 14 fungal species from black soybean meju (BSM) and buckwheat meju (BWM), respectively, on the basis of morphology, culture characteristics, and internal transcribed spacer and ${\beta}$-tubulin gene sequencing. In both meju, Aspergillus oryzae, Rhizopus oryzae, Penicillium polonicum, P. steckii, Cladosporium tenuissimum, C. cladosporioides, C. uredinicola, and yeast species Pichia burtonii were commonly found. Moreover, A. flavus, A. niger, P. crustosum, P. citrinum, Eurotium niveoglaucum, Absidia corymbifera, Setomelanomma holmii, Cladosporium spp. and unclassified species were identified from BSM. A. clavatus, Mucor circinelloides, M. racemosus, P. brevicompactum, Davidiella tassiana, and Cladosporium spp. were isolated from BWM. Fast growing Zygomycetous fungi is considered important for the early stage of meju fermentation, and A. oryae and A. niger might play a pivotal role in meju fermentation owing to their excellent enzyme productive activities. It is supposed that Penicillium sp. and Pichia burtonii could contribute to the flavor of the final food products. Identification of this fungal diversity will be useful for understanding the microbiota that participate in meju fermentation, and these fungal isolates can be utilized in the fermented foods and biotechnology industries.

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1740-1748
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• 2012

A home-made meju sample contaminated naturally with aflatoxins was used for isolation of fungal strains. Overall, 230 fungal isolates were obtained on dichloran rosebengal chloramphenicol (DRBC) and dichloran 18% glycerol (DG18) agar plates. Morphological characteristics and molecular analysis of a partial ${\beta}$-tubulin gene and the internal transcribed spacer (ITS) of rDNA were used for the identification of the isolates. The fungal isolates were divided into 7 genera: Aspergillus, Eurotium, Penicillium, Eupenicillium, Mucor, Lichtheimia, and Curvularia. Three strains from 56 isolates of the A. oryzae/flavus group were found to be aflatoxigenic A. flavus, by the presence of the aflatoxin biosynthesis genes and confirmatory aflatoxin production by high-performance liquid chromatography (HPLC). The predominant isolate from DRBC plates was A. oryzae (42 strains, 36.2%), whereas that from DG18 was A. candidus (61 strains, 53.5%). Out of the 230 isolates, the most common species was A. candidus (34.3%) followed by A. oryzae (22.2%), Mucor circinelloides (13.0%), P. polonicum (10.0%), A. tubingensis (4.8%), and L. ramosa (3.5%). A. flavus and E. chevalieri presented occurrence levels of 2.2%, respectively. The remaining isolates of A. unguis, P. oxalicum, Eupenicillium cinnamopurpureum, A. acidus, E. rubrum, P. chrysogenum, M. racemosus, and C. inaequalis had lower occurrence levels of < 2.0%.

• Korean Journal of Food Science and Technology
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• v.7 no.4
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• pp.229-237
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• 1975

An attempt was made to utilize the enzyme produced by Asp. oryzae as meat tenderizer. The production, purification, and various properties of proteinase produced by Asp. oryzae were investigated. Results obtained are as follow; 1. A strain which had the highest proteolytic activity was selected among 9 Aspergillus species. 2. Culture medium consisted of wheat bran 10g, 2% glucose, 0.03% urea and 0.1% $MgSO_4$ (pH 6.5). Mold was incubated at $30^{\circ}C$ for 3 days. 3. Enzyme extract from culture medium were fractionated with ammonium sulfate and purified by Sephadex G-75 column chromatography. 4. When pH of reaction mixture was controlled, maximal activity of proteinase by Asp. oryzae was obtained at pH 3, pH 6.6, $8.4{\sim}8.5$ and pH 10.0 to 10.5. Those results were interpreted to show that enzyme consists of acid proteinase, neutral proteinase and alkaline proteinase. Enzyme was stable at pH 6 to 10. 5. Opt. temperature for proteinase activity was $50^{\circ}C$, but enzyme was stable up to $40^{\circ}C$. 6. The proteinase was inhibited by $Ag^+$. It was also inhibited by EDTA. 7. When myofibrillar proteins were treated by proteinase from Asp. oryzae, ATPase activities of myofibrillar proteins changed remarkably. Accordingly, it was concluded that proteinase produced by Asp. oryzae were able to be used as meat tenderizer.

• Korean Journal of Poultry Science
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• v.32 no.4
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• pp.281-289
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• 2005

This study investigated the effect of dried food-waste diets(FW) fermented by Aspergillus oryzae(AO), on broiler growth performance, $NH_3$, emission and fecal microflora. Three hundreds broilers, two week old Hubbard strain, were randomly allotted to 4 experiments and fed with standards early boiler diet replaced with FW and AFW. In experiment 1, eighty four broilers were distributed into 7 treatments with 4 pens at 3 birds per replicate(pen). The dietary treatments ; T1 was com-soy bean meal based broiler diet(Control), T2, T3, T4 were for basal diet replaced with dried food waste without AO(FW) at the level of 20, 40 and $60\%$, respectively and T5, T6 and T7 followed the same levels for the basal diet but using Aspergillus oryzae inoculate food-waste(AFW). For experiments 2, 3, 4, seventy two broilers were distributed into 6 treatments with 4 pens at 3 birds per replicate(pen), respectively. The dietary treatments were the com-soy bean meal based broiler diet replacement with different combinations of FW and AFW, 1:0, 3:1, 1:1, 1:3, 0:1. at level of 20, 40 and $60\%$, respectively. In Exp. 1, it tended to be decreased in weight gain, however, there were no statistical differences among treatments except FW $60\%$ level of replacement(p<0.05). Feed intake and feed efficiency was not different among treatments. Total bacterial counts were not different between the control and FW diet, but E. coli decreased as the AFW levels of replacement were increased(p<0.05). There were no differences in weight gain, feed intake and feed efficiency among treatments in Exp. 2 and weight gains were lower fur FW diet compared with the control and AFW diet in Exp. 3(p<0.05). In Exp. 4, there were no differences in feed intakes among treatments, but lower in weight gain and feed efficiency in FW diet than that the control. In experiment 3, the $NH_3$ emission was the highest among treatments in FW/AFW 1:0 diet(p<0.05). From these results, it seems that FW would be supplemented up to $20\%$ in broiler diets and AO culture extract could improve FW value as feed supplements.

• Microbiology and Biotechnology Letters
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• v.26 no.1
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• pp.68-75
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• 1998

The overproduction and high level secretion of Glucose Oxidase (GOD) from A. niger in S. cerevisiae was carried out by cloning GOD gene. For this purpose, using two different strong promoters (ADH1 promoter, GAL10 promoter) and signal sequences (${alpha}$-MF signal sequence of S. cerevisiae and ${alpha}$-amylase signal sequence of A. oryzae) and GAL7- and GOD terminator, four expression vectors were constructed. All the expression vectors were transformed in S. cerevisiae 2805 using auxotroph method. By the flask culture, transformants of pGAL expression vector series containing GAL 10 promotor showed much higher GOD productivity than transformants of pADH expression vector series containing ADH1 promoter Transformants of pGALGO2 containing GAL10 promotor and ${alpha}$-amylase signal sequence has shown the best productivity of GOD ($GOD_{total}$: 10.3 unit/mL, $GOD_{ex}$: 8.7 unit/mL) at 115 hr. This value was three fold higher than that of pGALGO1 containing GAL 10 promotor and ${alpha}$-MF signal sequence, even if the same promotor was involved. Through the ${alpha}$-amylase signal sequence of A. oryzae, GOD was secreted much more than the case of ${alpha}$-MF signal sequence from S. cerevisiae. These results suggest that signal sequence may play a important roles in not only the secretion but also the overproduction of foreign protein. Secretion rate of GOD in pGALGO1 and pGALGO2 was 89% and 84%, respectively, Because of the overglycosylation in S. cerevisiae the molecular weight of recombinant GOD in S. cerevisiae was much larger (250 kDa) than that of nature GOD in A. niger (170 kDa).

• Korean Journal of Microbiology
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• v.7 no.4
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• pp.159-166
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• 1969

It is necessry to develop and strengthen the activity of enzymic source which in low applied for maggerley brewing as an amylolytic and proteolytic starter, recently in this country the active and strong enzymic starter is required for the better brewing and to substitute another starch material for the present wheat flour. In this study, manufacturing method the strong enzymic source have been developed and established with use of raw wheat bran plus fungal strains of Rhizopus sp. and Aspergillus usamii the culture of starter. The results on experimental the activities of enzymic sources (stater) are as following ; 1. Method of making the enzymic source (starter) is to cultivate the strains of Asperguillus orzyae, Asp. kawachii, Asp usamii and Rhizopus sp. in the acid treated raw or heatboiled wheat bran. 2. The saccharogenic pwoer (S.P.) of enzymic source which consisted of raw bran plus fungi and cultured in it is generally stronger than those of heat-boiled bran plus fungi, the strongest power was shown in the culture of Rhizopus plus raw bran, and the next other is in mixture of Asp.usamii and Rhizopus on raw wheat bran. 3. The most strong alpha amylase activity was expressed in the plot of Asp.oryzae on heat-boiled wheat bran, the next was in the culture of Rhizopus nad Aspergillus usamii on raw wheatbran. 4. The most vigourous acidic proteinase activity was expressed in the micture of raw bran plus Asp. usamii and Rhizopus those were independentlu cu;tured before mixing for neutral proteinase activity, it was shown in the mixed culture of Asp. usamii and Rhizopus on raw wheat bran, the msot active alkaline proteinase activity of enzymic source was found in the plot of raw bran material. 5. For poly-preptidase activity in pH 6.5 it is found that the culture of Rhizopus and Asp.usamii on raw bran was most active among them of enzymic sources. 6. Generally, it is concluded that culture of fungi on acid treated raw wheat bran is stronger in its activity than those of heat boiled wheat bran, especially the culture of Rhizopus nad Asp.usamii on raw bran exhibited the most vigorous and non-polarized activity for all aspects, so it is considered to be most desirable enzymic stater in Korean Maggerley brewing and this would be able to substitute brewing material for the present wheat flour because of its strong and wide hand activity of amylolytic and proteolytic action.