• The Korean Journal of Mycology
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• v.12 no.4
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• pp.141-152
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• 1984

Aspergillus niger van Tieghem was cultured by the method of synchronous and submerged culture. Throughout the culture, sporulation was occured. Highly phosphorylated nucleotides in sporulating mycelia were detected to assure whether the eucaryotic Aspergillus niger produce these substances or not during the differentiation. Phosphorylated nucleotides were extracted from the conidiophore, bearing mycelia and spore forming body, these nucleotides were identified by TLC with P.E.I. cellulose. Guanosine tetraphosphate was found in both phialide forming mycelia and spore forming body. The contents of free amino acids were assayed and its level was found to increase at early stage of sporulation. The effects of 8-azaguanine examined, it was found to prevent spore formation and to made abnormal structure. The effects of inosinic monophosphate and guanosine monophosphate on spore formation were examined, spore formation was enhanced by these nucleotides.

• Korean Journal of Food Science and Technology
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• v.13 no.2
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• pp.121-126
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• 1981

An adenine-guanine doubless and $\beta$-alanine requiring mutant, D-1550-40, which had been derived from Brevibacterium ammoniagenes ATCC 6872, produced a copious amount of xanthosine-5'-monophosphate (XMP). The optimum concentration of adenine and guanine for maximal accumulation of XMP was about 75 ml/l and 100 ml/l for growth. Concentrations higher than 100 mg/l of adenine and guanine inhibited cell growth and XMP accumulation strongly. The inhibition, however, could be recovered by adding $100{\mu}g$ of biotin per liter or 0.3% of casamino acids to the culture solution. High concentrations of phosphate and magnesium salts (1.0 to 1.5%(w/v) in media) were found to be indispensable for XMP accumulation, and the presence of manganese in the culture medium stimulated both growth of cells and accumulation of XMP leaving 5'-inosinic acid unaffected. The maximal accumulation of XMP reached to 60.5 mg/l after 4 days of fermentation which had been started with a medium containing 100 mg of adenine-guanine, 5 mg of $MnSO_4{\cdot}H_2O$ and $100{\mu}g$ of biotin per liter. The specific XMP synthesis(mg of XMP/mg of cells) was increased with the increase of the cell growth rate.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.6
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• pp.833-838
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• 2015

To develop a value-added product from individually quick-frozen oyster Crassostrea gigas extract (IQFOE), we prepared two types of oyster sauce (OS): bottled OS (BOS) and retort pouched OS (ROS). We investigated processing conditions, quality metrics and flavor compounds in each type of sauce. We found that the most appropriate base formular for both BOS and ROS consisted of 40.0% IQFOE (Brix $30^{\circ}$), 15.0% sugar, 6.0% salt, 4.0% monosodium glutamate, 4.0% soy sauce, 3.5% starch, 3.0% yeast extract, 3.5% wheat flour and 21.0% water. The crude protein, salinity and amino-nitrogen contents of the BOS and ROS were 8.2 and 8.3%, 9.3 and 9.2%, and 539.2 and 535.2 mg/100 g, respectively. In commercial oyster sauces (COS), these values were 4.7-6.5%, 9.7-12.0%, and 244.7-504.2 mg/100 g, respectively. The total free amino acids content of ROS was 7,346.9 mg/100 g, and the main free amino acids were glutamic acid, taurine, proline, glycine and alanine. The inosinic monophosphate (IMP) content of the ROS was 131.6 mg/100 g, and the primary inorganic ions were Na, K, S and P. The present BOS and ROS have favorable organoleptic qualities and storage stability compared with COS, and are suitable for commercialization as high-flavor seasoning sauces.

• Microbiology and Biotechnology Letters
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• v.7 no.3
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• pp.119-125
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• 1979

As the first step of domestic developmint of the nucleic acid-related compounds, purine base required auxotrophs from Brevibacterium ammoniagenes ATCC 6872 were derived by the ultraviolet irradiation or the treatment of N-methyl-N'-nitro-N-nitroso guanidine (NTG), diethyl sulfate (DES), and ethylme-thyl sulfate (EMS). The optimum conditions of mutation by means of several mutagens were induced respectively. The yield of mutants was 0.083％ by the ultraviolet irradiation, 0.67％ by the NTG treatment, 1.1％ by the DES treatment, and 0.45％ by the EMS treatment. Six strains among 239 auxotrophs were screened out to accumulate 5'-lMP in the culture broth. Cry-stalline 5'-lMP was isolated from the culture broth of Brevifbacterium ammoniagenes adnine-guanine less mutant D-21530 by the use of anion exchange resin, Amberlite IRA-402, and it was identified physically and chemically as 5'-inosinic acid.