• Korean Journal of Environmental Agriculture
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• v.29 no.1
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• pp.86-91
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• 2010

This study was carried out to assess the antifungal potential of R. oligosporus and its ethyl acetate (EtOAc) extract against the fungal pathogens causing anthracnose disease in apple fruits using disc diffusion, antagonistic effect and morphological abnormalities in fungal mycelia. The percentage of inhibition of antifungal effect of the ethyl acetate extract (5 ${\mu}l$ $disc^{-1}$) of the R. oligosporus against C. acutatum KACC 40848, C. gloeosporioides KACC 40897, C. higginsianum KACC 40806, C. orbiculare KACC 40808, C. coccodes KACC 40008, C. musae KACC 40947, C. boninense KACC 40893, C. liliacearum KACC 40981, C. caudatum KACC 41028 and Colletotrichum sp. KACC 40811 was found to be 44.4, 35.5, 40, 31.1, 33.3, 37.7, 40, 51.1, 28.8 and 28.8%, respectively. Also the fungus R. oligosporus showed potential antagonistic effect of antifungal activity against the tested pathogens of Colletotrichum spp. Further, R. oligosporus had a potential detrimental effect on the morphology of the tested fungi of Colletotrichum spp. such as wrinkle abnormalities, abnormal cell formation, lysis of mycelium, empty cell formation, distorted cell formation and breakage of the mycelium. These findings strongly support the role of R. oligosporus to serve as a potential antifungal agent to control plant pathogenic fungi causing anthracnose disease in apple fruits.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.10
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• pp.1369-1379
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• 2010

This study investigated purification and milk-clotting activity of the enzymes produced by Bacillus subtilis var, natto and Rhizopus oligosporus compared with that of commercial rennet. The clotting time, viscosity, tension and microstructure of the curd and electrophoretic patterns of milk proteins were determined. The milk-clotting activity/proteolytic activity ratios (MCA/PA ratio) of B. subtilis, R. oligosporus and commercial rennet were also compared. The results revealed that the curd formed by the commercial rennet had the highest viscosity and curd tension and the shortest clotting time among the three enzymes. However, curd produced by Rhizopus enzymes was ranked as second. From the MCA/PA ratio and electrophoretogram analyses it could be concluded that the enzyme produced by B. subtilis had the highest proteolytic activity, while the commercial rennet had the highest milk-clotting activity. Observations of microstructures of SEM showed that the three-dimensional network for curd formed by commercial rennet was denser, firmer and more smooth. The milk-clotting activity, specific activity, purification ratio and recovery of the purified enzymes produced by both the tested organisms were also determined with ion exchange chromatography and gel filtration.

• The Korean Journal of Mycology
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• v.26 no.4 s.87
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• pp.478-486
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• 1998

The isolates of Rhizopus collected from Korean traditional fermented food meju and nuruk, were compared with the well known species of Rhizopus donated. The isolates of Rhizopus were identified with the numerical analyses calculated from RAPD-DNA bands, and confirmed with the microscopic observations of morphological features on PDA. The isolates of R. oryzae purchased were segregated through the results of RAPD or the morphological features. The species of R. nigricans, known as an illegitimate species, were different from those of R. stolonife and it is estimated that they are species of Rhizopus, again. According to microscopic observations and the result of RAPD, Some isolates of R. oryzae purchased belong to R. nigricans and are completely different from R. oryzae in their growth. The isolates of R. nigricans included with several isolates of R. oryzae identified for the different phenotypes and were heterogenous. The isolate of R. oligosporus were speculated to be different from morphological features of Rhizopus, but to be similar to the species of Absidia on the apophysis of sporangium. Its sporangiophore or mycelium was observed to be dark black, but the sporangia were not in those of R. oligosporus. The isolates collected from Korean traditional nuruk showed genetic diversity, and also considered to be different tastes in Korean rice wines.

• Nutrition Research and Practice
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• v.8 no.5
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• pp.539-543
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• 2014

BACKGROUND/OBJECTIVES: Soy isoflavones are structurally similar to estrogen and bind to estrogen receptors, suggesting that they exhibit estrogenic activities; therefore, they are referred to as phytoestrogens. Fermentation may affect the bioavailability of isoflavones altering soy isoflavone glycosides in the form of aglycones. Thus, this study investigated the effects of fermented soybeans by Rhizopus oligosporus on bone metabolism in both young rats as a pilot test and in ovariectomized (ovx) old rats as a model of menopause. MATERIALS/METHODS: In the pilot test, a total of 24 seven-week-old female Sprague-Dawley (SD) rats were fed one of three diets for a period of four weeks: casein, unfermented soybean product, or fermented soybean product by R. oligosporus. In the ovx rat model, 20-week-old SD rats weighing 260-290 g underwent either sham-operation (n = 10) or bilateral ovariectomy (n = 30) and were then fed the AIN-93M diet for one week. Thereafter, rats were fed sham-casein, ovx-casein, ovx-soybean, or ovx-fermented soybean diet for five weeks. After decapitation, femoral bones were isolated and preserved in 9% formalin for assessment of bone mineral density (BMD), bone mineral content (BMC), and bone-breaking strength (BBS). RESULTS: Ovx rats showed significantly increased weight gain and decreased uterine wet weight. Of particular interest, ovx rats fed fermented soybeans showed increased uterine wet weights compared to control rats. Fermented soybean diet caused a significant increase in plasma 17-${\beta}$ estradiol concentrations in young rats, and 17-${\beta}$ estradiol levels were enhanced in ovx rats to match those of sham-operated ones. Significantly lower femoral BMD and BMC were observed in ovx rats compared to sham-operated controls, whereas bone areas did not differ statistically among the groups. In addition, BBS tended to be increased in ovx rats fed soybeans and fermented soybeans. CONCLUSIONS: Supplementation of fermented soybeans could have preventive and therapeutic effects against osteoporosis in postmenopausal women.

• Journal of Microbiology and Biotechnology
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• v.20 no.8
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• pp.1226-1229
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• 2010

Glyceollins, one of the inducible phytoalexins produced by plants, were induced in a number of varieties of Korean soybean through fungal infection. Of the tested soybean varieties, Tae-Kwang, though not the most productive, was found to be currently the most suitable for the induction of glyceollins. Amongst the fungal species, Rhizopus microsporus var. oligosporus was seen to be the most effective elicitor. Halved soybean seeds produced glyceollins upon fungal infection; however, chopped soybeans and homogenized soybeans did not produce significant quantities of glyceollins.

• 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.

• Food Science and Preservation
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• v.9 no.3
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• pp.315-320
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• 2002

In order to improve some problems such as contamination of undesirable mold, mycotoxin production and excessive drying on the surface of traditional meju. Control meju without koji and capsule type meju(CM) coated with soybean mixture containing 0.5%, 1% and 2%(w/w) R. oligosporus koji were dried at room temperature (10∼15$^{\circ}C$) for 3 days. Control meju I was fermented in outdoor for 27 days. Control meju IIand CMs were fermented in Korean yellow clay room at 25$^{\circ}C$ for 7 days under 80% relative humidity as first step, and then fermented in outdoor (average temp. 2.7$^{\circ}C$, December) for 20 days as second step. The moisture content of CMs were higher than that of control meju I to the range of 2.88∼7.55%(w/w). pH and titratable acidity in CMs were similar to control group. Amino type nitrogen content in CMs(800.80, 816.0, 901.60 mg%) were 2.2∼2.6 times higher than that in control meju I (347.2 mg%). Reducing sugar content in CMs(2.78∼3.13%) was similar to control meiu I (2.10%) and control meju H(2.31%). Lightness(L) value of control meju I was higher than that of control meju IIand CMs.

• 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).