• Microbiology and Biotechnology Letters
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• v.6 no.4
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• pp.167-171
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• 1978

When Asp. niger was shaked at 3$0^{\circ}C$ in 500 mι Erlenmeyer flask with 50 ml of the medium containing 14% of Korean local commercial glucose brand, 0.45% of peptone, and mineral, the citric acid was produced at the level of 37~43 gram per liter in 8 days, and the citric acid production at medium containing X glucose brand was better than that containing Y glucose brand. When the contaminated minerals were removed from the local glucose by Ambelite-IR 120 and peptone by potassium ferrocyanide followed by readjustment of ferric ion content in the medium to 10 mg per liter, the citric acid formation reached 53 gram per liter, a production level of three times higher than that with the original Sakaguchi's medium. The further physiological studies and the mutation of isolated Asp. niger will be needed.

• Applied Biological Chemistry
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• v.14 no.1
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• pp.19-27
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• 1971

This experiment was conducted as a preliminary test to invent the quick ripening process for soysauces. The bran koji extract of 2 kinds of mold (Asp. niger and Asp. sojae) was used as enzyme sources in order to improve the rate of enzymatic conversion of raw materials and shorten the ripening period of soysauces. Soybean koji (inoculated Asp. sojae) and steamed soybean were enzymatically decomposed for 8 hours at $40^{\circ}C$, pH 4-6 with stirring at a rate of 1500 rpm. After the enzymatic treatment, soysauces were fermented by 4 kinds of processes with the above-mentioned salt tolerant microorganisms inoculated. After 4 weeks, sensory evolution for these soysauces products and analysis of chemical components were carried out. The results obtained were summarized as follows. 1. Soysauces prepared from decomposed koji by Asp. niger enzyme complex showed higher extractables, such as total nitrogen, amino nitrogen, pure extract and reducing sugar, than any other procedure. Extracted amounts of each components of soysauces prepared from this process during 1 month were similar to those of soysauces made from general procedure (control) for 5 to 6 months. 2. According to sensory evaluation, soysauce prepared from decomposed koji also showed best taste and were similar to that of soysauces prepared by general method for 6 months.

• The Korean Journal of Mycology
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• v.1 no.2
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• pp.9-14
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• 1973

Author investigated fluorence antibody reaction for the antigenic relationships between Asp niger group, Asp flavus and Asp parasiticus which was indicated as follows: 1. It was concluded that there are complete differences in the antigenic properties each other because it has not cross reaction, therefore identification of strains will be simpley classified. 2. A complete cross reaction between Asp flavus and Asp parasitic us in the Asp flavus groups existed, accordingly this reaction could not identified the strain and classified between Asp. flavus and Asp. parasiticus. 3. This experiment also followed with the separated each strains from the origin (Meju, Nuruk, ATCC, NRRL), but there no differences. From the above results, this method could be classified between Asp flavus group and Asp niger group in the genus Aspergillus, but classification of Asp. flavus and Asp. parasiticus should hardely conclude with this method.

• KSBB Journal
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• v.19 no.1
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• pp.42-49
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• 2004

A gene coding for epoxide hydrolase (EH) of Aspergillus niger LK, a fungus possessing the enantioselective hydrolysis activity for racemic epoxides, was characterized by phylogenetic analysis. The deduced protein of A. niger LK epoxide hydrolase shares significant sequence similarity with several bacterial EHs and mammalian microsomal EHs (mEH) and belongs to the a/${\beta}$ hydrolase fold family. EH from A. niger LK had 90.6% identity with 3D crystal structure of lqo7 in Protein Data Bank. Sequence comparison with other source EHs suggested that Asp$\^$l92/, Asp$\^$374/ and His$\^$374/ constituted the catalytic triad. Based on the multiple sequence comparison of the functional and structural domain sequence, the phylogenetic tree between relevant epoxide hydrolases from various species were reconstructed by using Neighbor-Joining method. Genetic distances were so far as 1.841-2.682 but characteristic oxyanion hole and catalytic triad were highly conserved, which means they have diverged from a common ancestor.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.2
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• pp.69-76
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• 1990

To substitute the soy-sauce 'koji' used in fish sauce processing with molded sardine meal(MSM) 'koji', the culture conditions of MSM be inoculated with Aspergillus spp. were investigated. To prepare the MSM, Asp. awamori(KFCC. 11439), Asp. guercinus (KFCC. l1595), Asp. niger(KFCC. 11239), Asp. oryzae(KFCC. 32343), and Asp. sojae(KFCC. 11559) were inoculated upon the chopped sardine with $20\%$ (w/w) corn starch after steriling it at $121^{\circ}C$ for 15min. Sporulation time cultured with Asp. spp. at $30^{\circ}C$ was 48hrs and color of mycelium on the surface of MSM inoculated with Asp. awamari and Asp. oryzae were black, that of MSM inoculated with the other strains were yellowish brown. The activity of protease and lipase from the MSM were increased till the 72hrs of culture at $30^{\circ}C$, while the content of trimethylamine was decreased after 96hrs of culture period at same condition with exception of Asp. niger. Asp. oryzae and Asp. sojae showed superior in pro-tease and lipase activity in comparison with the other strains, and maximum activity of protease and lipase of MSM was observed after 72hrs of culture period. The optimum pH and temperature for the activity of MSM inoculated with Asp. oryzae and Asp. sojae were pH 9.0, $30\~35^{\circ}C$ and pH $6\~7$, $35^{\circ}C$, respectively.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.510-518
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• 1989

Most of orange peels are disposed from orange juice manufacturing process. Thus, our purpose is to utilize these orange peels as fermentation substrate. We have investigated culture conditions and factors influencing citric acid production by an isolated strain, Asp. niger. Citric acid production was much higher in semisolid culture than in submerged culture and the particle size of ground orange peels was favored at 20 mesh in semisolid culture. The optimal pH and temperature were 4.5-5.0 and 3$0^{\circ}C$ respectively and the temperature cycling at 35$^{\circ}C$ for 20 hrs durig exponential phase, 1$0^{\circ}C$ for 4 hrs and 3$0^{\circ}C$ during stationary phase showed higher citric acid production than did at fixed temperature, 3$0^{\circ}C$. The addition of NH$_4$NO$_3$0.2%, MgSO$_4$7$H_2O$ 0.1%, methanol 2.5%, ethanol 1.5%, to culture medium promoted citric acid production but the addition of trace metal ions as nutrients had not effect on the acid production in orange peel medium. Under the optimal culture conditions, maximum yield of citric acid was 80.4% in solid medium. Almost of all original components of citrus peel was consumed by Asp. niger during fermentation.

• Korean Journal of Microbiology
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• v.12 no.4
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• pp.180-187
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• 1974

Of the Asp. spp. isolated by the Institute of Applied Microbiology, Kon-Kuk University, 7 strains were selected for the study of the immunological differencences among them using gel precipitation test. The strains were the following types : 1 type of flavus and 2 types of oryzae were isolated from Meju ; 1 type of flavus from Nuruk ; and each one type of flavus, parasiticus and oryzae from Kokja.Asp.flavus from ATCC, Asp. parasiticus nad Asp. niger NRRL strains were also used in the study as a standard. From this study, several points can be raised ; 1) There was no common antigenic property between Asp. niger and Asp. flavus, because of no formation of reaction line. Therefore, all strains could be easily distinguished. 2) There was common antigenic property, that is, the formation of reaction line between Asp. flavus and Asp. parasticus. Accordingly two strains could not be easily distinguished by the gel precipitation test. 3) Each type of oryzae, parasiticus and flavus of Asp. flavus group had common antigen one another as well as specific antigens only in the difference of the reaction lines, so they could be easily identified in the gel precipitation test. 4) Each isolated strain from Meju and Nuruk appeared to be identical. 5) It was shown that the gel precipitation test of serological methods was very useful for the classification of Asp. spp.

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.477-486
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• 1991

To elucidate enzymatic properties of a-glactosidase (EC 3.2.1.22) from Asp. niger, a-galactosidase from wheat bran culture was purified by ammonium sulfate fractionation, ion exchange chromatography and gel filtration. And then its enzymatic propeties were investigated. The highest level of $\alpha$-galactosidase activity was obtained when Asp. niger was grown on wheat bran medium at $30^{\circ}C$ for 96 hours. The $\alpha$-galactosidase was purified by 23.7 fold by ammonium sulfate fractionation, ion exchange chromatography on DEAE-Celluose and Sephadex A-50, and gel filtration on Sephadex G-150 and its specific activity was 1,229 Unitslmg protein and the yield was 14% of the total activity of wheat bran culture. The purified $\alpha$-galactosidase was found to be homogeneous by polyacrylamide gel electrophoresis and HPLC. The $\alpha$-galactosidase was a tetrameric glycoprotein which consisted of identical subunits with molelcular weight of 28,000 each by SDS-PAGE and isoelectric point was determined analytical isoelectric focusing to be pH 4.6. The optimal temperature and pH for the $\alpha$-galactosidase activity were $40^{\circ}C$ and pH 6.5, respectively, and 54% of its activity was lost by heating at $60^{\circ}C$ for 10 mins, It was appeared to have higher affinty to raffinose than to stachyose. The K, value and activation energy of $\alpha$-galactosidase were 5.0 mM and 8.515 Kcal per mole for p-nitrophenyl- $\alpha$--D-galactopyranoside, respectively.

• Applied Biological Chemistry
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• v.25 no.4
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• pp.252-256
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• 1982

To investigate the influences of biological factors on stored rice and their interactions, the activities of red Hour beetle(Tribolium castaneum) and 2 species of Aspergillus was observed during 6 weeks at $28^{\circ}C{\pm}1^{\circ}C$. It was found that the red flour beetle could complete its life cycle on rice in six weeks. Its activity caused the increse of moisture content of rice(max. 1.3%) after 6 weeks, but the number of mold propagule on the surface of stored rice decreased. The growth of red flour beetle showed a stabilizing tendency on rice inoculated with Asp. repens while it was retarded with Asp. niger.

• Microbiology and Biotechnology Letters
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• v.6 no.1
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• pp.9-16
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• 1978

Effects of the addition of Ginseng extract and it's incubation time on enzyme activity (${\alpha}$-amylase, ${\beta}$-amylase, protease) of Aspergillus app. was investigated. 1. ${\alpha}$-Amylase activity of Asp. oryzae was higher for 48 hours than control, however, the same after 48 hours. ${\beta}$-Amylase activity was stimulated at the concentration of 0.1 to 1.0％, and decreased at the concentration of 3.0 to 5.0％. The acid protease activity was higher than control for 72 hours and in the medium of 120 hours was decreased significantly. The alkaline protease activity was lower than control. However, alkaline protease activity was higher than acid protease activity. 2. ${\alpha}$-Amylase of Asp. niger was increased in proportion to increasing of the extract concentration. ${\beta}$-Amylase was increased at the concentration from 0.5 to 3.0％ and it's activity was depressed in proportion to increasing of the extract concentration for 48 hours and on the contrary it was improved in proportion to increasing of the extract concentration for 72 hours except for 5.0％ concentration with marked decreasing. Alkaline protease activity was increased at lower concentration (0.1∼0.5％) for 24 to 48 hours and it was depressed at higher concentration (1.0 to 5.0), however after 48 hours incubated, it's activity was decreased in preparation to increasing of the extract concentration.