• Mycobiology
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• 제44권4호
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• pp.269-276
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• 2016

Aspergillus luchuensis is known as an industrially important fungal species used for making fermented foods such as awamori and shochu in Japan, makgeolli and Meju in Korea, and Pu-erh tea in China. Nonetheless, this species has not yet been widely studied regarding mating-type genes. In this study, we examined the MAT1-1 and MAT1-2 gene ratio in black koji molds (A. luchuensis, Aspergillus niger, and Aspergillus tubingensis) and in Aspergillus welwitschiae isolated from Meju, a fermented soybean starting material for traditional soy sauce and soybean paste in Korea. The number of strains with the MAT1-1 locus was 2 of 23 (A. luchuensis), 6 of 13 (A. tubingensis), 21 of 28 (A. niger), and 5 of 10 (A. welwitschiae). Fungal species A. tubingensis and A. welwitschiae showed a 1 : 1 ratio of MAT1-1 and MAT1-2 mating-type loci. In contrast, A. luchuensis revealed predominance of MAT1-2 (91.3%) and A. niger of MAT1-1 (75%). We isolated and identified 2 A. luchuensis MAT1-1 strains from Meju, although all strains for making shochu in Japan are of the MAT1-2 type. These strains may be a good resource for breeding of A. luchuensis to be used in the Asian fermented-food industry.

• 한국균학회지
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• 제41권2호
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• pp.132-135
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• 2013

검은 Aspergillus 속균은 동양의 발효산업에서 매우 중요한 곰팡이로서 식품산업에 관련된 검은 Aspergillus를 흑국균이라고 한다. 흑국균은 A. luchuensis, A. niger, A. tubingensis로 구성이 되어 있는데 이 중에서 A. luchuensis는 동양의 발효산업에서 매우 중요한 곰팡이로 알려져 있다. 우리나라 전통 된장과 간장의 주요 원료가 되는 메주에서도 검은 Aspergillus가 흔히 발견되었다. 33균주의 검은 Aspergillus가 2008년부터 2011년 사이에 전국적으로 수집한 98개의 완성메주로부터 분리되었고 추가로, 발효과정에 있는 메주로부터 검은 Aspergillus 21균주를 분리하였다. ${\beta}$-tubulin과 calmodulin 유전자 염기서열 분석을 통하여 이들을 동정한 결과 이들은 A. niger 21균주, A. luchuensis 14균주, A. tubingensis 10균주, A. welwitschiae 9균주로 동정되었다. 이 중 A. luchuensis는 생장이 활발하고 단백질, 지방, 탄수화물 분해력이 높은 것으로 조사되어 이들의 산업적 응용에 대한 추가의 연구가 필요한 것으로 사료된다.

• Mycobiology
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• 제44권3호
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• pp.171-179
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• 2016

In the screening of marine mangrove derived fungi for lovastatin productivity, endophytic Aspergillus luchuensis MERV10 exhibited the highest lovastatin productivity (9.5 mg/gds) in solid state fermentation (SSF) using rice bran. Aspergillus luchuensis MERV10 was used as the parental strain in which to induce genetic variabilities after application of different mixtures as well as doses of mutagens followed by three successive rounds of genome shuffling. Four potent mutants, UN6, UN28, NE11, and NE23, with lovastatin productivity equal to 2.0-, 2.11-, 1.95-, and 2.11-fold higher than the parental strain, respectively, were applied for three rounds of genome shuffling as the initial mutants. Four hereditarily stable recombinants (F3/3, F3/7, F3/9, and F3/13) were obtained with lovastatin productivity equal to 50.8, 57.0, 49.7, and 51.0 mg/gds, respectively. Recombinant strain F3/7 yielded 57.0 mg/gds of lovastatin, which is 6-fold and 2.85-fold higher, respectively, than the initial parental strain and the highest mutants UN28 and NE23. It was therefore selected for the optimization of lovastatin production through improvement of SSF parameters. Lovastatin productivity was increased 32-fold through strain improvement methods, including mutations and three successive rounds of genome shuffling followed by optimizing SSF factors.

• Journal of Biomedical and Translational Research
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• 제19권4호
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• pp.103-109
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• 2018

Aspergillus luchuensis 34-1 was inoculated into wheat pellets with different conditions of raw materials to produce nuruk. The degree of substrate reactivity improvement of steam treated raw materials compared with that of non-heat treated was analyzed. The water content of the pellet was adjusted to 25% and 35%, and steam treatment for 10 minutes improved the substrate reactivity at 2.1-fold and 3.1-fold, and sterilization was also possible. The characteristics of improvement pellet nuruk were investigated according to the degree of crushing and water content of raw materials according to the temperatures and humidities ($23^{\circ}C$, $30^{\circ}C$ and RH 60%, RH 80%). The pH of the pellet nuruk was higher depending on the temperature, humidity and moisture content of the koji were lower, and the pH of the flour-pellet nuruk was lower than that of 2 mm milling wheat-pellet nuruk according to milling degree. It can be seen that the milling degree affects the growth of mold. The acidity and amino acid were generally higher as fermentation time increased. Also, the higher the incubation temperature, humidity and moisture content, the higher the value. Glucoamylase activity was significantly the highest in moisture content 35% D2b nuruk, cultured at $30^{\circ}C$ and 80% RH for 38 hours. This is higher than the previous reports on glucoamylase of rice-koji or commercial nuruk using fungi isolated from traditional nuruk. From these study, it is expected that making of improvement pellet nuruk would save the fermentation time considerably compared with traditional nuruks.

• Mycobiology
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• 제43권3호
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• pp.218-224
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• 2015

Aspergillus is an important fungal genus used for the fermentation of Asian foods; this genus is referred to as koji mold in Japan and China. A. oryzae, A. sojae, and A. tamari are used in the production of miso and shoyu in Japan, but a comprehensive taxonomic study of Aspergillus isolated from Meju, a fermented soybean starting material for traditional soy sauce and soybean paste in Korea, has not been conducted. In this study, various Aspergillus species were isolated during a study of the mycobiota of Meju, and the aspergilli were identified based on phenotypic characteristics and sequencing of the ${\beta}$-tubulin gene. Most strains of Aspergillus were found to belong to the following sections: Aspergillus (n = 220), Flavi (n = 213), and Nigri (n = 54). The most commonly identified species were A. oryzae (n = 183), A. pseudoglaucus (Eurotium repens) (n = 81), A. chevalieri (E. chevalieri) (n = 62), A. montevidensis (E. amstelodami) (n = 34), A. niger (n = 21), A. tamari (n = 15), A. ruber (E. rubrum) (n = 15), A. proliferans (n = 14), and A. luchuensis (n = 14); 25 species were identified from 533 Aspergillus strains. Aspergillus strains were mainly found during the high temperature fermentation period in the later steps of Meju fermentation.

• 한국균학회지
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• 제43권3호
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• pp.149-157
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• 2015

장류와 주류 제조를 위하여 국내에서 유통되는 하경발효의 황국균(HK1), 수원발효의 황국균(SW101), 백국균(SW201), 충무발효의 된장용 황국균(CF1001), 간장용 황국균(CF1002), 청주용 황국균(CF1003), 주류용 백국균(CF1005)과 전통 메주에서 분리하여 산업화 준비를 하고 있는 황국균(KACC 93210)의 분류학적 특성과 안전성을 조사하였다. 공시한 6균주의 황국균은 모두 A. oryzae로 동정되었으며 이중 HK1, SW101, CF1001, CF1003은 분생포자를 생성하는 대(stipe)의 길이가 중간크기($711{\sim}1,121{\mu}m$, 중모(中毛))로써 서로 유사한 형태적 및 분자계통학적 특성을 나타내었으나 청주용인 CF1003이 다른 3균주에 비하여 포자를 다소 적게 그리고 균사를 다소 많이 생성하였다. 간장제조용인 CF1002는 대의 길이가 평균 $543{\mu}m$로서 짧았으며(단모(短毛)) omtA 유전자 분석에서 다른 황국균이 ICAo 그룹에 위치하는 반면에 IBLB-그룹에 소속되어 명쾌히 구분되었다. 전통메주에서 분리되어 산업화 과정에 있는 황국균 KACC93210 균주는 대(stipe)가 평균 $270{\mu}m$로 매우 짧았으며(초단모(超短毛)) 다른 황국균이 양털모양의 집락을 형성하는 반면 벨벳모양의 집락을 형성하여 형태적으로 쉽게 구분되었고 omtA 유전자에서도 공시한 황국균은 물론 세계적으로 보고된 어떤 황국균과도 염기서열이 서로 달랐다. 수원발효의 백국균(SW201)과 충무발효의 백국균(CF1005)은 모두 A. luchuensis (또는 A. luchuensis mut. kawachii)로 동정되었으며 집락 형태가 다소 상이하였으나 기타의 형태적 특징과 분자계통학적 특징에서 서로 구분되지 않았다. 황국균 6균주는 aflatoxin, cyclopiazonic acid, sterigmatocystin의 곰팡이 독소를 생성하지 않았고 백국균(A. luchuensis)은 유해한 독소를 생성하지 않는 것으로 이미 보고되었으므로 국내에 유통되는 황국균과 백국균은 모두 곰팡이독소에서 안전한 곰팡이임이 입증되었다.

• 한국식품저장유통학회지
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• 제23권6호
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• pp.797-803
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• 2016

본 연구에서는 전분 및 단백질 분해력이 우수한 토착 발효종균 Aspergillus luchuensis 74-5 및 Aspergillus oryzae 75-2로 제조한 고체종국의 품질 특성을 조사하였다. 액체종국 접종량 5%와 10% 접종하였을 때, pH는 각각 5.78 및 3.85 이하로, 적정산도는 2.12와 8.54 이상, 아미노산도는 1.15 및 2.66 이상으로 균주에 따라 차이를 보였다. 효소활성의 변화는 발효종균에 따라 증감 패턴이 특징적으로 나타났고, 액국 접종량에 따라 A. luchuensis 74-5는 접종량이 증가할수록 ${\alpha}-amylase$와 glucoamylase 활성은 증가하나 acidic protease활성은 감소하였고, A. oryzae 75-2는 5% 접종하였을 때 모든 효소활성이 가장 높게 나타났다. 발효온도는 저온보다 중온(35, $40^{\circ}C$)에서 효소활성이 우수한 것으로 나타났고, 발효시간은 종균에 따라 차이는 있지만 각각 144시간과 120시간일 때 효소활성이 높은 것으로 나타났다. 발효조건에 따른 고체종국의 포자수는 약 $2.0{\times}10^7$, 세균의 오염은 약 $3.0{\times}10^3$으로 나타났으며, 세균에 의한 오염도 저감화 및 효소활성을 유지하기 위하여, 구연산, 종국의 건조법 및 부형제 등의 추가적인 연구가 필요하다.

• Mycobiology
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• 제51권5호
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• pp.288-299
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• 2023

Aspergillus is one of the largest and diverse genera of fungi with huge economical, biotechnological, and social significance. Taxonomically, Aspergillus is divided into six subgenera comprising 27 sections. In this study, 235 strains of Aspergillus subgenus Circumdati (section: Candidi, Circumdati, Flavi, Flavipedes, Nigri, and Terrei) preserved at the Korean Agricultural Culture Collection (KACC) were analyzed and re-identified using a combined dataset of partial b-tubulin (BenA), Calmodulin (CaM) gene sequences and morphological data. We confirmed nineteen species to be priorly reported in Korea (A. neotritici, A. terreus, A. floccosus, A. allahabadii, A. steynii, A. westerdijkiae, A. ochraceus, A. ostianus, A. sclerotiorum, A. luchuensis, A. tubingensis, A. niger, A. welwitschiae, A. japonicus, A. nomius, A. tamarii, A. parasiticus, A. flavi, and A. oryzae). Among the studied strains, three species (A. subalbidus, A. iizukae, and A. uvarum), previously unreported or not officially documented, were discovered in Korea, to the best of our knowledge. We have given a detailed description of the characteristic features of the three species, which remain uncharted in Korea.

• Mycobiology
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• 제35권4호
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• pp.191-195
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• 2007

The colonization pattern and extent of decay produced in paddy stubble by soil inhabiting mycoflora were done by using nylon net bag technique. Among the three methods used for isolation of fungi, dilution plate technique recorded the highest number of fungi followed by damp chamber and direct observation method. Nutrient availability and climatic conditions (temperature, humidity and rainfall) influenced the occurrence and colonization pattern of fungi. Maximum fungal population was recorded in October ($48.99{\times}10^4/g$ dry litter) and minimum in May ($11.41{\times}10^4/g$ dry litter). Distribution of Deuteromycetous fungi was more in comparison to Zygomycetes, oomycetes and ascomycetes. In the early stage of decomposition Mucor racemosus, Rhizopus nigricans, Chaetomium globosum and Gliocladium species were found primarly whereas at later stages of decomposition preponderance of Aspergillus candidus, Torula graminis, Cladosporiun cladosporioides and Aspergillus luchuensis was recorded.

• 한국수산과학회지
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• 제51권4호
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• pp.369-375
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• 2018

This study investigated the effects of selected seaweeds on rice koji preparation (rice inoculated with Aspergillus luchuensis) and enzyme activity. Four types of rice koji were prepared using one of three seaweeds (0.5% laver, 0.5% kelp and 0.5% green laver) or a control for 72 h. The changes in the moisture content, water activity, pH, total mold cell count, amylase and protease activities were measured. During preparation, there was no significant difference in the moisture content among the four kojis, whereas the pH in the kojis made with either laver or green laver decreased rapidly compared with the control (P<0.05). This seemed to result from the seaweeds promoting the growth of mold cells. In terms of the activities of both amylase and protease, the koji with laver was superior. Subsequently, the amylase and protease activities of the koji made with laver were evaluated at various pHs (3 to 9), temperatures ($15-55^{\circ}C$) and NaCl concentrations (0-10%). The activities of both enzymes decreased notably at pH 9 and the protease activity decreased at temperatures above $45^{\circ}C$. Although the activities of both enzymes decreased at greater than 2.5% NaCl, activity was present at 10% NaCl.