• Mycobiology
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• v.47 no.3
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• pp.301-307
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• 2019

The $11{\alpha}$-hydroxylation of $16{\alpha}$, 17-epoxyprogesterone (EP) catalyzed by Rhizopus nigricans is crucial for the steroid industry. However, lower conversion rate of the biohydroxylation restricts its potential industrial application. The $11{\alpha}$-steroid hydroxylase CYP509C12 from R. oryzae were reported to play a crucial role in the $11{\alpha}$-hydroxylation in recombinant fission yeast. In the present study, the CYP509C12 of R. oryzae (RoCYP) was introduced into R. nigricans using the liposome-mediated mycelial transformation. Heterologous expression of RoCYP resulted in increased fungal growth and improved intracellular reactive oxygen species content in R. nigricans. The $H_2O_2$ levels in RoCYP transformants were approximately 2-folder that of the R. nigricans wild type (RnWT) strain, with the superoxide dismutase activities increased approximately 45% and catalase activities decreased approximately 68%. Furthermore, the $11{\alpha}$-hydroxylation rates of EP in RoCYP transformants (C4, C6 and C9) were 39.7%, 38.3% and 38.7%, which were 12.1%, 8.2% and 9.4% higher than the rate of the RnWT strain, respectively. This paper investigated the effect of heterologous expression of RoCYP in R. nigricans, providing an effective genetic method to construct the engineered strains for steroid industry.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.2
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• pp.125-140
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• 2016

We analyzed the cultural characteristics of isolated brewing fungi for developing fermentation starters. In a previous study, we collected 87 domestic nuruk, from which 481 fungi strains were isolated and 11 were selected showing improved productivity. After culturing these 11 fungi strains in several types of media, temperatures, carbon and nitrogen sources, Rhizopus sp. grew well in MEA, ME20S, PDA medium while Aspergillus sp. grew well in ME20S and YES. Both Rhizopus sp. and Aspergillus sp. survived well at optimal growth temperatures of 30 and $37^{\circ}C$. Rhizopus sp. utilized lactose, glucose and peptone sources while Aspergillus sp. utilized glucose, mannose, fructose and yeast extract sources. ${\alpha}-Amylase$ activity was excellent in L. ramosa CN044, R. oryzae 82-7(MEB), R. oryzae CN174 and A. oryzae 58-11(WEB) culture extracts. This study suggests that R. delemar 26-4, 58-8 and A. oryzae 78-5, 37-7 might be appropriate fungi strains for fermentation starters based on development of large fungi bodies and their good enzyme activities.

• Korean Journal of Microbiology
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• v.20 no.3
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• pp.134-146
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• 1982

This experiment was designed to elucidate the life cycle of 7 species (Rh.nigricans, Rh. delemar, Rh.oryzae, Rh.acidus, Rh.tritici, Rh. formosaensis and Rh. japonicus) in genus Rhizopus isolated from Korean soil, so as to seize the appropriate stage for detecting their chromosomal number and nuclear size under the method of thin layer slide culture using modified Rogers(1965a) medium. The results are summarized as the folowings ; 1. The haploid chromosome number are found 16 in Rh. japonicus are 8, respectively. 2. Comparing the 7 species of Rhizopus with each other, it may be concluded that the basic haploid chromosome number of genus Rhizopus distributed in Korean soil are 8 and that Rh. nigricans is double of the basic hapolid chromosome number (n = 16). Besides them, the other two species (Rh. tritici and Rh. formosaensis) are believed aneuploids.

• Food Science and Preservation
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• v.23 no.1
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• pp.117-126
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• 2016

This study was performed to provide information for improving the quality characteristics of tangerine peel Soksungjang. Tangerine peel Soksungjangs were prepared with 10% tangerine peel powder by addition of different koji such as Rhizopus oligosporus (RS, RTS) and Aspergillus oryzae (AS, ATS). As a result, the moisture content was not changed and crude protein content decreased during fermentation in all samples. The pH of RS (Soksungjang manufactured with Rhizopus oligosporus koji) and RTS (Soksungjang manufactured with Rhizopus oligosporus koji and 10% tangerine peel powder) was not changed, whereas pH of AS (Soksungjang manufactured with Aspergillus oryzae) and ATS (Soksungjang manufactured with Aspergillus oryzae koji and 10% tangerine peel powder) decreased rapidly after 10 days of fermentation. The acidity values of all the samples increased during fermentation. The major free sugars were glucose, fructose, and maltose; while, the major organic acids were citric acid, succinic acid, acetic acid, and lactic acid in all the samples. The amino nitrogen content and protease activity were highest in the AS and ATS. Conversely, the reducing sugar content and ${\alpha}$-amylase activity were highest in the RS and RTS. The major free amino acids in all samples were glutamic acid, lysine, leucine, and arginine. Sixty kinds of volatile flavor compounds were identified from all samples; the majority of which were 21 alcohols, 14 hydrocarbons, 5 esters, and others identifies as acids, ketones, and aldehydes.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.277-288
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• 2017

Rhizomucor miehei NRRL 5282 and Rhizopus oryzae NRRL 1526 can produce lipases with high synthetic activities in wheat bran-based solid-state culture. In this study, the purification and biochemical characterization of the lipolytic activities of these lipases are presented. SDS-PAGE indicated a molecular mass of about 55 and 35 kDa for the purified R. miehei and Rh. oryzae enzymes, respectively. p-Nitrophenyl palmitate (pNPP) hydrolysis was maximal at $40^{\circ}C$ and pH 7.0 for the R. miehei lipase, and at $30^{\circ}C$ and pH 5.2 for the Rh. oryzae enzyme. The enzymes showed almost equal affinity to pNPP, but the $V_{max}$ of the Rh. oryzae lipase was about 1.13 times higher than that determined for R. miehei using the same substrate. For both enzymes, a dramatic loss of activity was observed in the presence of 5 mM $Hg^{2+}$, $Zn^{2+}$, or $Mn^{2+}$, 10 mM N-bromosuccinimide or sodium dodecyl sulfate, and 5-10% (v/v) of hexanol or butanol. At the same time, they proved to be extraordinarily stable in the presence of n-hexane, cyclohexane, n-heptane, and isooctane. Moreover, isopentanol up to 10% (v/v) and propionic acid in 1 mM concentrations increased the pNPP hydrolyzing activity of R. miehei lipase. Both enzymes had 1,3-regioselectivity, and efficiently hydrolyzed p-nitrophenyl (pNP) esters with C8-C16 acids, exhibiting maximum activity towards pNP-caprylate (R. miehei) and pNP-dodecanoate (Rh. oryzae). The purified lipases are promising candidates for various biotechnological applications.

• The Korean Journal of Mycology
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• v.24 no.4 s.79
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• pp.280-292
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• 1996

The fungal isolates of Mucorales, directly collected from Korean traditional raw materials of Nuruk (raw material for Korean rice wine) and Meju (raw material for Korean soysauces), were compared with those of Rhizopus oryzae purchased. The fungal isolates of Rhizopus, Mucor, and Absidia mostly identified as based on the morphological observations, were evaluated with the PCR-polymorphic bands. The PCR-polymorphic bands of the genomic DNA reacted with the primers of OPD series tenmer were various, but showed averaged 4 to 6 in the agarose-electrophoresis. The dissimilarity coefficient (DC) between two isolates were compared by the cluster analyses, dendrogams and polar ordinations. The isolates of R. oryzae known. showed several groupings within the lower value of DC and were divided to two groups of amylo-process and other fungi with other purposes. The isolates unidentified were identified by the DC made of this results. Taxonomy of these isolates made by the morphological observations were consistent with those resulted above in most case but not in all aspects. More works were needed with the isolates known for detail informations of Mucorales.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.759-766
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• 1997

From Nuruks, a traditional Korean starter for rice wine, collected from 42 different areas in Korea, 111 fungal strains were isolated. These isolates were identified as 25 species belonging to seven genera of Rhizopus oryzae(14 strains), R. oligosporus(8 strains), R. nigricans(5 strains), R. arrhizus (5 strains), Aspergillus oryzae(12 strains),Asp. parasiticus(8 strains), Asp. fumigatus(3 strains), Asp. ochraceus(7 strains), Asp. wentii(5 strains), Asp. parasiticus(8 strains), Asp. penicilloides(3 strains), Asp. clavatus(4 strains), Penicillium purpurogenum(2 strains), Pen. glabrum(1 strain), Pen. granulaturm (1 strsin), Pen. fellutanum(1 strain), Geotrichum candidum(2 strains), Absidia corymbifera(12 strains), Mucor racemosus(2 strains), M. plumbeus(2 strains) and Curvularia lunatus(3 strains).

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.243-246
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• 2002

In this study, biological production of fumaric acid by Rhizopus oryzae KCTC 6946 using rotary biofilm contactor was investigated. In study of neutralizing agent on fumaric acid production, $Na_2CO_3$ was more effective than NaOH. After 24 hr of incubation with a rotating speed of 10 rpm at $35^{\circ}C$, biofilm was grown on and around the surface of the disks. The yield and volumetric productivity of rotary biofilm contactor were 33.8% and 0.595 g/L${\cdot}$h, respectively, with the optimum effective disk surface area of 1,583 $cm^2/L$.

• Journal of Microbiology and Biotechnology
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• v.27 no.8
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• pp.1409-1418
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• 2017

Two typical microbial communities from Chinese rice wine fermentation collected in Yichang city and Suzhou city in China were investigated. Both communities could ferment glutinous rice to rice wine in 2 days. The sugar and ethanol contents were 198.67 and 14.47 mg/g, respectively, for rice wine from Yichang city, and 292.50 and 12.31 mg/g, respectively, for rice wine from Suzhou city. Acetic acid and lactic acid were the most abundant organic acids. Abundant fungi and bacteria were detected in both communities by high-throughput sequencing. Saccharomycopsis fibuligera and Rhizopus oryzae were the dominant fungi in rice wine from Suzhou city, compared with R. oryzae, Wickerhamomyces anomalus, Saccharomyces cerevisiae, Mucor indicus, and Rhizopus microsporus in rice wine from Yichang city. Bacterial diversity was greater than fungal diversity in both communities. Citrobacter was the most abundant genus. Furthermore, Exiguobacterium, Aeromonas, Acinetobacter, Pseudomonas, Enterobacter, Bacillus, and Lactococcus were highly abundant in both communities.

• Journal of Microbiology and Biotechnology
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• v.19 no.11
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• pp.1328-1332
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• 2009

An activity-guided fractionation method was used to isolate anticancer components from Nuruk (Rhizopus oryzae KSD-815:KSD-815). Dried powder of KSD-815 was extracted with 80% methanol and partitioned successively using n-hexane, ethyl acetate, n-butanol, and water. The n-hexane and n-butanol fractions showed a strong antimigratory effect on human cancer cells. Both of these fractions were subjected to separation and purification procedures using silica gel, octadecyl silica gel, and Sephadex LH-20 column chromatographies to afford four purified compounds. These were identified as ergosterol peroxide (1), stigmast-5-en-$3\beta$,$7\beta$-diol (2), ergosta-7,22-dien-$3\beta$,$5\alpha$,$6\beta$,$9\alpha$-tetraol (3), and daucosterol (4), respectively, by spectroscopic methods such as nuclear magnetic resonance spectrometry, mass spectrometry, and infrared spectroscopy, and comparison with those in the literature. Compounds 1-4 were isolated from KSD-815 for the first time. Compounds 1 and 4 inhibited the migration of MDA-MB-231 cells at concentrations lower than $20\;{\mu}M$.