• Journal of Microbiology and Biotechnology
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• v.5 no.5
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• pp.274-279
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• 1995

Ethyl caproate, one of the major flavor compounds deciding the quality of sake (Japanese wine), is produced during the brewing by the action of alcohol acyltransferase and esterases of sake yeast and koji mold. Extracellular esterases of Aspergillus oryzae required for ethyl caproate synthesis were purified partially. The enzymes had different optimum pH and affinity toward substrates. Substrate preferences and inhibition features showed the three enzymes to be B-type esterases or carboxylesterases (EC 3.1.1.1).

• Journal of Microbiology and Biotechnology
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• v.9 no.5
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• pp.568-571
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• 1999

Aspergillus oryzae U1521, which was a genetically engineered strain, produced 1,000,600 U per g . glucose of extracellular alkaline protease within 72 h in a submerged fermentation. However, the alkaline protease was not detected during the first 24 h. Northern blot analysis indicated that the enzyme synthesis was repressed at the transcriptional level during the lag period. Both catabolite repression and pH of the growth medium significantly affected the enzyme production. Use of this enzyme as a silver recovery agent from used X-ray film was confirmed by experiments in the shake-flask scale.

• Mycobiology
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• v.40 no.3
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• pp.208-209
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• 2012

The amino acid sequence of the mheA gene of Aspergillus oryzae encodes a putative metallothionein-like protein 1. The size of the mheA transcript was 497 nt and the mheA promoter was induced by glucose, consistent with results of analysis by Northern hybridization and with the pdcA promoter, respectively.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.57-66
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• 2017

Aflatoxins are classified as Group 1 (carcinogenic to humans) by the International Agency for Research on Cancer. In this study, a total of 134 fungal strains were isolated from 65 meju samples, and two fungal isolates were selected as potential aflatoxin $B_1$ ($AFB_1$)-biodetoxification fungi. These fungi were identified as Aspergillus oryzae MAO103 and A. oryzae MAO104 by sequencing the beta-tubulin gene. The two A. oryzae strains were able to degrade more than 90% of $AFB_1$ (initial concentration: $40{\mu}g/l$) in a culture broth in 14 days. The mutagenic effects of $AFB_1$ treated with A. oryzae MAO103 and MAO104 significantly decreased to 5.7% and 6.4%, respectively, in the frame-shift mutation of Ames tests using Salmonella typhimurium TA98. The base-substituting mutagenicity of $AFB_1$ was also decreased by the two fungi. Moreover, $AFB_1$ production by Aspergillus flavus was significantly decreased by the two A. oryzae strains on soybean-based agar plates. Our data suggest that the two $AFB_1$-detoxifying A. oryzae strains have potential application to control $AFB_1$ in foods and feeds.

• The Korean Journal of Mycology
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• v.21 no.4
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• pp.247-272
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• 1993

Forty-eight fungal isolates were collected from the Korean traditional maejus and twenty-eight isolates of them were identified to be a hyphomycetous fungus(three genera and 20 species) Aspergillus flavus, A. flavus var columnaris, A. oryzae, A, oryzae var effusus, A. terreus, Scopula­riosis brevicaulis, Penicillium botryosum, P. gorlenkoanum, P. griseo-purpureum, P. citrinum, P. miczynskii, P. gaditanum, P. turolense, P. funiculosum, P. rubicundum, P. godlewskii, P. jensenii, P. roqueforti, P. volguense, P. verrucosum. Various 14 species of Penicillium were isolated from maejus, but all of them were not considered to be involved in the maeju fermentation. Otherwise, S. brevicaulis was especially collected from the maejus of various located areas, but were also related to the good quality of maejus under labratory conditions. A. flavus, A. oryzae P. tulolense, and P. funiculosum were also observed to be involved in the process of maeju.

• Journal of Microbiology and Biotechnology
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• v.22 no.1
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• pp.100-106
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• 2012

In this study, the metabolite profiles of three Aspergillus strains during rice koji fermentation were compared. In the partial least squares discriminant analysis-based gas chromatography-mass spectrometry data sets, the metabolite patterns of A. oryzae (KCCM 60345) were clearly distinguished from A. kawachii (KCCM 60552) and only marginal differences were observed for A. oryzae (KCCM 60551) fermentation. In the 2 days fermentation samples, the overall metabolite levels of A. oryzae (KCCM 60345) were similar to the A. oryzae (KCCM 60551) levels and lower than the A. kawachii (KCCM 60552) levels. In addition, we identified discriminators that were mainly contributing tyrosinase inhibition (kojic acid) and antioxidant activities (pyranonigrin A) in A. oryzae (KCCM 60345) and A. kawachii (KCCM 60552) inoculated rice koji, respectively. In this study, we demonstrated that the optimal inoculant Aspergillus strains and fermentation time for functional rice koji could be determined through a metabolomics approach with bioactivity correlations.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.1-8
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• 2017

The production of high-value chemicals from natural resources as an alternative for petroleum-based products is currently expanding in parallel with biorefinery. The use of lignocellulosic biomass as raw material is promising to achieve economic and environmental sustainability. Filamentous fungi, particularly Aspergillus species, are already used industrially to produce organic acid as well as many enzymes. The production of lignocellulose-degrading enzymes opens the possibility for direct fungal fermentation towards organic acids such as itaconic acid (IA) and fumaric acid (FA). These acids have wide-range applications and potentially addressable markets as platform chemicals. However, current technologies for the production of these compounds are mostly based on submerged fermentation. This work showed the capacity of two Aspergillus species (A. terreus and A. oryzae) to yield both acids by solid-state fermentation and simultaneous saccharification and fermentation. FA was optimally produced at by A. oryzae in simultaneous saccharification and fermentation (0.54 mg/g wheat bran). The yield of 0.11 mg IA/g biomass by A. oryzae is the highest reported in the literature for simultaneous solid-state fermentation without sugar supplements.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.296-302
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• 2002

Quality characteristics of mash of takju prepared by wheat flour nuruks (conventional and improved style) were investigated during fermentation. Those were cultured with wild microorganism on whole and crushed wheat (wheat nuruk), wheat flour and mixture of rice and wheat flour, and nuruk cultured with Aspergillus oryzae on wheat flour. Ethanol content reached maximum of 10.6-17.4% after 14 days of fermentation. And the ethanol contents of takju were high in order of wheat nuruk, wheat flour nuruk, Aspergillus oryzae nuruk and mixture of wheat flour and rice nuruk. No difference of pH was among the treatments while the wheat flour nuruk cultured with wild microorganisms contained higher amounts of acids than the others. The amount of total sugars ranged from 16.22-17.74% on the starting day of fermentation, and decreased to 4.28-6.10% after 14 days. The amount of total sugars in mashes brewed with wheat flour nuruk cultured with Aspergillus oryzae was measured to be highest at the beginning stage of fermentation. Afterwards no difference was found among the types of nuruks. Glucose was in the range of 2,735-7,842 mg% at initial period of fermentation, afterwards it was rapidly decreased. The total amounts of free sugar for control and the wheat flour nuruk was higher than other treatments. The total amounts of organic acids were the highest in wheat nuruk to 690-2,241 mg% and the contents of lactic acid and succinic acid were high in mixed rice nuruk to 183-1,293 mg%. The contents of lactic acid and succinic acid were higher than those of the other kinds of organic acids in takju.

• Korean Journal of Food Science and Technology
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• v.22 no.7
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• pp.786-792
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• 1990

In order to study the possibility of savoury material production from fish flesh(Alaska pollack), as a substrate of fermentation, three strains of Aspergillus oryzae were applied to the flesh solely or with soybean. The fermented flesh were analyzed their amino acid compositions, nucleotide contents and their sensory acceptability. All strains tested were grown vigorously on both substrates. When fish flesh solely used, amino nitrogen($NH_2-N$) and soluble solid (S.S.) contents were $8{\sim}14\;and\;2{\sim}3$ times higher than those of raw flesh, respectively after 7 days fermentation. In case of fish flesh with 10% soybean used, their $NH_{2}-N$ and S.S. contents were $4{\sim}6\;and\;2.6{\sim}3$ times higher than those of raw flesh respectively. It was belived that increment of $NH_2-N$ and S.S. contents were resulted from degradation of fish flesh protein. On the other hand, the nucleotides and their related compounds of both fermented flesh and with 10% soybean were increased comparing with raw flesh. The content of free amino acids of flesh solely and with 10% soybean were $1,435{\sim}4,326mg%(DB)\;and\;5,563{\sim}6,362mg%(DB)$, which increased to between $4.6{\sim}13.9\;and\;11.6{\sim}13.2$ times, respectively after 7 days fermentation. The four amino acids- glutamic acid, histidine, aspartic acid and lysine were major in both flesh solely and flesh with 10% soybean. In sensory evaluation, fermented flesh extracts was more acceptable than anchovy extract. In review of all results, Aspergillus oryzae KFCC 32343 could be successfully used for production of savoury material from Alaska pollack.

• Food Science and Preservation
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• v.8 no.2
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• pp.199-205
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• 2001

Red mold was isolated from meju prepared by traditional mtehod and characterized. The isolated red mold grew well on potato dextrose agar medium, In microscopic observation, it had a septum in mycelium and ellipsoidal spore. Optimal temperature and pH for growth were 30$\^{C}$ and 6.0, respectively. Enzyme activities such as protease, a-amylase and glucoamulase in ted mold were lower than those in Aspergillus oryzae. A competitive growth between red mold and Asp. oryzae was greatly affecten by cultivation temperature. The growth of isolated red mold on meju was predominant at below 30$\^{C}$ as compared with Asp. oryzae.