• Food Science and Biotechnology
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• 제17권4호
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• pp.888-891
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• 2008

Twenty-three fungal strains were isolated from meju that had originated from the Sunchang province, the famous location for making fermented soybean foods in Korea. The restriction fragment length polymorphism (RFLP) of the internal transcribed spacer (ITS) region of the rDNA (ITS-RFLP) was applied to differentiate the isolated fungal strains. First, the ITS region by polymerase chain reaction (PCR) with specific primers was amplified and then cleaved the products with different restriction enzymes. Cleavage of the amplified fragments with the restriction enzymes AluI, HaeIII, HhaI, and TaqI revealed extensive polymorphisms. The ITS-RFLP results highly correlated with ITS sequence analysis. All of the 23 fungal strains were classified into 5 groups by ITS-RFLP analysis. Aspergillus oryzae was the major fungal strain isolated from Sunchang meju (12 out of 23), while Aspergillus fumigatus was the next most frequently isolated strain (7 out of 23). In contrast, it was found that Fusarium asiaticum, Aspergillus sydowii, and Arthrinium sp. were the minor fungal strains in meju.

• Journal of Microbiology and Biotechnology
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• 제24권3호
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• pp.334-336
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• 2014

A new species named Aspergillus cumulatus sp. nov. is described in Aspergillus section Aspergillus (Eurotium state). The type strain (KACC $47316^T$) of this species was isolated from rice straw used in meju fermentations in Korea, and other strains were isolated from the air in a meju fermentation room. The species is characterized by growth at a wide range of water activities and the formation of aerial hyphae on malt extract 60% sucrose agar (ME60S) that resemble a cumulus cloud. Furthermore, A. cumulatus produces yellow ascomata containing small lenticular ascospores (5.1-5.7 ${\mu}m$) with a wide furrow, low equatorial crests, and tuberculate convex surface. The species is phylogenetically distinct from the other reported Aspergillus section Aspergillus species based on multilocus sequence typing using rDNA-ITS, ${\beta}$-tubulin, calmodulin, and RNA polymerase II genes.

• Mycobiology
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• 제37권4호
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• pp.251-257
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• 2009

We isolated and identified a strain of Eurotium rubrum from Meju that has not been reported in Korea. This fungus is yellowish brown; reverse dark brown on CYA and PDA while yellow on 2% MEA at $25{^{\circ}C}$. Cleistothecia are first bright yellow and gradually turned brown. Mycerial growth on CYA attained a diameter of 30 mm at $20{^{\circ}C}$, 37 mm at $25{^{\circ}C}$ and 32 mm at $30{^{\circ}C}$ after 15 days. The isolate grew slower on 2% MEA ($<$ 20 mm 15 days at $25{^{\circ}C}$) compared to CYA and PDA ($<$ 40 mm 15 days at $25{^{\circ}C}$). Cleistothecia are superficial, yellow to light brown, globose to subglobose, 40~75 ${\mu}m$ in diameter. Asci are 8-spored and globose to subglobose 8~11 ${\mu}m$. Ascospores are disciform, 4.0~5.0 ${\mu}m$ in length and 4.2~4.5 ${\mu}m$ in width. Conidia are ovate or bacillar, finely roughened to densely spinulose, 4.6~6.0 ${\mu}m$ in length and 3.0~4.3 ${\mu}m$ in width. Compared to known Eurotium rubrum, the Korean isolate showed 99% sequence similarity in ITS rDNA (554 bp) and calmodulin (750 bp) gene and 100% in $\beta$-tubulin (1016 bp) gene. The E. rubrum isolate also had weak $\beta$-glucosidase and protease activities.

• 한국균학회지
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• 제26권4호통권87호
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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.

• Journal of Microbiology and Biotechnology
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• 제22권12호
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• pp.1740-1748
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• 2012

A home-made meju sample contaminated naturally with aflatoxins was used for isolation of fungal strains. Overall, 230 fungal isolates were obtained on dichloran rosebengal chloramphenicol (DRBC) and dichloran 18% glycerol (DG18) agar plates. Morphological characteristics and molecular analysis of a partial ${\beta}$-tubulin gene and the internal transcribed spacer (ITS) of rDNA were used for the identification of the isolates. The fungal isolates were divided into 7 genera: Aspergillus, Eurotium, Penicillium, Eupenicillium, Mucor, Lichtheimia, and Curvularia. Three strains from 56 isolates of the A. oryzae/flavus group were found to be aflatoxigenic A. flavus, by the presence of the aflatoxin biosynthesis genes and confirmatory aflatoxin production by high-performance liquid chromatography (HPLC). The predominant isolate from DRBC plates was A. oryzae (42 strains, 36.2%), whereas that from DG18 was A. candidus (61 strains, 53.5%). Out of the 230 isolates, the most common species was A. candidus (34.3%) followed by A. oryzae (22.2%), Mucor circinelloides (13.0%), P. polonicum (10.0%), A. tubingensis (4.8%), and L. ramosa (3.5%). A. flavus and E. chevalieri presented occurrence levels of 2.2%, respectively. The remaining isolates of A. unguis, P. oxalicum, Eupenicillium cinnamopurpureum, A. acidus, E. rubrum, P. chrysogenum, M. racemosus, and C. inaequalis had lower occurrence levels of < 2.0%.

• 생명과학회지
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• 제22권5호
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• pp.605-612
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• 2012

포자형성균은 사람과 동물용의 프로바이오틱 제제로서 사용되어져 왔다. 포자형성균의 낮은 pH에 대한 안정성과 위내 생육저해 환경에 생존능은 프로바이오틱 제제로서 매력적이다. 본 연구는, 한국 전통 대두 발효 식품의 종균인 BCNU 9028균주를 메주로부터 분리하였다. 생리학적, 생화학적 특성과 16S 리보좀 DNA 염기서열 분석 결과 BCNU 9028균주는 $Bacillus$에 속하는 것을 확인하였다. $Bacillus$ sp. BCNU 9028은 pH 2.5에서 92%의 생존률을 보였으며, 0.3% 담즙산에서도 저항성을 나타냈다. 그리고, 식품 병원성균과의 응집정도와 자가결합능에 의해 $Bacillus$ sp. BCNU 9028는 $Listeria$ $monocytogenes$, $S.$ $aureus$ 및 $E.$ $coli$와 같은 식품 병원성균의 생물막형성과 부착을 저해할 수 있는 것을 확인하였다. BCNU 9028의 소수성 특성(63.3%)은 장관내 부착능이 우수할 것으로 나타났다. 특히, $Bacillus$ sp. BCNU 9028 균주는 그람양성 및 그람음성 병원성균 모두에 항균력을 갖는 것을 확인하였다. 이상의 결과로 $Bacillus$ sp. BCNU 9028균주가 프로바이오틱스로서 이용가능성이 있음을 제시하였다.

• 한국미생물·생명공학회지
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• 제40권2호
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• pp.98-103
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• 2012

경기도 일대에서 수집한 메주 시료에서 지질분해 활성을 나타내는 균주 Y124를 분리하여 동정한 결과 Yarrowia lipolytica와 100% 상동성을 보였다. 분리 균주가 생산하는 lipase의 조효소에 대한 일반적인 특성을 조사한 결과, 탄소원으로 olive oil을 단독으로 사용한 YPO 배지에서 8시간 배양하였을 때 lipase 활성이 가장 높게 나타났다. YPD 배지에서는 lipase 활성이 거의 없었으며, olive oil과 glucose를 모두 포함하는 YPDO 배지에서는 lipase 활성이 YPO 배지 보다 낮았다. 그리고 olive oil 농도에 따른 lipase 활성을 측정한 결과, olive oil 무첨가보다 0.7% 첨가하여 8시간 배양했을 때 lipase 활성이134 U/mL으로 가장 높게 나타나 lipase의 생산이 olive oil의 첨가에 의해 유도되는 것으로 생각된다. 생육온도에 따른 lipase 활성 측정한 결과, $30^{\circ}C$에 배양하였을 때 배양 8시간에 가장 높은 활성이 나타났고, $25^{\circ}C$와 $37^{\circ}C$에 배양하였을 때는 배양 12시간에 활성이 가장 높게 나타났으며, Y124균주의 lipase 활성 최적 온도는 $30^{\circ}C$로 나타났다. 그리고 lipase의 기질 친화도를 확인한 결과 Y124균주가 생산하는 lipase의 경우 p-nitrophenyl octanoate ($C_8$)에서 가장 높은 활성이 나타났다.