• Journal of Microbiology and Biotechnology
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• 제14권5호
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• pp.952-958
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• 2004

Of 23 psychrotrophic bacteria isolated from the west Pacific deep-sea sediments, 19 were assigned to the $\gamma$-Proteobacteria, 3 to the <$\beta$-Proteobacteria, and 1 to the Gram-positive bacteria, as determined by their 16S rDNA sequences. Ten psychrotrophs, affiliated to the Psychrobacter, Pseudoalteromonas, and Pseudomonas genera in the $\gamma$-Proteobacteria group, were screened for lipolytic bacteria. The majority of the lipolytic isolates had growth temperatures between 4-$30^\circ{C}$, and all of them were neutrophilic, aerobic, or facultatively anaerobic, and some were able to produce multiple kinds of ectohydrolytic enzymes. The deep-sea strains Psychrobacter sp. wp37 and Pseudoalteromonas sp. wp27 were chosen for further lipase production analysis. Both strains had the highest lipase production when grown at 10 to $20^\circ{C}$; their highest lipase production occurred at the late-exponential growth stage; and the majority of the enzymes were excreted to the outside of the cells. Lipases from both strains had the same optimal reaction temperature and pH (20-$30^\circ{C}$, pH 7-8) and could retain about 60% of their highest activity at $4^\circ{C}$. Furthermore, SDS-PAGE and an in-gel activity test showed that they had the same high molecular mass of about 85 kDa.

• Journal of Microbiology and Biotechnology
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• 제26권5호
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• pp.883-890
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• 2016

Marine sediments are a microbial biosphere with an unknown physiology, and the sediments harbor numerous distinct phylogenetic lineages of Bacteria and Archaea that are at present uncultured. In this study, the structure of the archaeal and bacterial communities was investigated in the surface and subsurface sediments of Jeju Island using a next-generation sequencing method. The microbial communities in the surface sediments were distinct from those in the subsurface sediments; the relative abundance of sequences for Thaumarchaeota, Actinobacteria, Bacteroides, Alphaproteobacteria, and Gammaproteobacteria were higher in the surface than subsurface sediments, whereas the sequences for Euryarchaeota, Acidobacteria, Firmicutes, and Deltaproteobacteria were relatively more abundant in the subsurface than surface sediments. This study presents detailed characterization of the spatial distribution of benthic microbial communities of Jeju Island and provides fundamental information on the potential interactions mediated by microorganisms with the different biogeochemical cycles in coastal sediments.

• Journal of Microbiology and Biotechnology
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• 제25권3호
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• pp.353-357
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• 2015

A new actinomycete strain NA4 was isolated from a deep-sea sediment collected from the South China Sea and showed promising antifungal activities against soilborne fungal pathogens. It was identified as Streptomyces cavourensis by morphological, physiological, and phylogenetic analyses based on its 16S rRNA gene sequence. The main antifungal components were isolated and identified from the fermentation culture as bafilomycins B1 and C1. These compounds exhibited significant antifungal activities and a broad antifungal spectrum. The results suggest that the Streptomyces cavourensis NA4 and bafilomycins B1 and C1 could be used as potential biocontrol agents for soilborne fungal diseases of plants.

• Journal of Species Research
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• 제9권4호
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• pp.339-345
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• 2020

The Earth contains billions of microbial species, although the vast majority cannot be cultured in laboratories and are thus considered unidentified and uncharacterized. Extremophiles are microorganisms that thrive in extreme conditions, including temperature, salinity, and pH. Extremophilic microorganisms have provided important insights for biological, metabolic, and evolutionary studies. Between 2017 and 2019, as part of a comprehensive investigation to identify bacterial species in Korea, eight bacterial strains were isolated from marine and non-marine environments in Jeju Island. These strains were cultured under extreme salinity or pH conditions. Phylogenetic analysis using 16S ribosomal RNA(rRNA) gene sequencing indicated that all eight strains belonged to the phyla Gammaproteobacteria, Bacilli, and Alphaproteobacteria. Based on their high 16S rRNA gene sequence similarities(>98.7%) and the formation of strong monophyletic clades with their closest related species, all isolated strains were considered as an unrecorded strain, previously unidentified species. Gram stain reaction, culture conditions, colony and cell morphology, biochemical characteristics, isolation source, and National Institute of Biological Resources(NIBR) IDs are described in this article. The characterization of these unrecorded strains provides information on microorganisms living in Korea.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권6호
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• pp.553-556
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• 2006

A cis-1,2-dichloroethylene (cis-DCE)-degrading anaerobic bacterium, Clostridium sp. strain KYT-1, was isolated from a sediment sample collected from a landfill site in Nanji-do, Seoul, Korea. The KYT-1 strain is a gram-positive, endospore-forming, motile, rod-shaped anaerobic bacterium, of approximately $2.5{\sim}3.0\;{\mu}m$ in length. The degradation of cis-DCE is closely related with the growth of the KYT-1 strain, and it was stopped when the growth of the KYT-1 strain became constant. Although the pathway of cis-DCE degradation by strain KYT-1 remains to be further elucidated, no accumulation of the harmful intermediate, vinyl chloride (VC), was observed during anaerobic cis-DCE degradation. Strain KYT-1 proved able to degrade a variety of volatile organic compounds, including VC, isomers of DCE (1,1-dichloroethylene, trans-1,2-dichloroethylene, and cis-DCE), trichloroethylene, tetrachloroethylene, 1,2-dichloroethane, 1,1,1-trichloroethane, and 1,1,2-trichloroethane. Strain KYT-1 degraded cis-DCE at a range of temperatures from $15\;to\;37^{\circ}C$, with an optimum at $30^{\circ}C$, and at a pH range of 5.5 to 8.5, with an optimum at 7.0.

• 한국균학회지
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• 제48권4호
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• pp.423-443
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• 2020

Freshwater fungi are a poly-phylogenetic group of taxonomically diverse organisms. In this study, we isolated diverse fungal strains from various environmental samples obtained from freshwaters in Korea. These strains were identified by performing molecular phylogenetic analyses of rDNA and/or other sequences (beta-tubulin, RNA polymerase II, and translation elongation factor 1). In addition, we examined their morphological characteristics microscopically and cultural characteristics using different media. We identified eleven unrecorded Pezizomycotina species: Cladosporium angulosum, Pseudorobillarda phragmitis, Paraconiothyrium estuarinum, Pseudopithomyces palmicola, Pyrenochaetopsis paucisetosa, Thelebolus globosus, Plagiostoma mejianum, Trichoderma cremeum, Fusarium tanahbumbuense, Coniochaeta endophytica, and Chaetomium tenue. Environmental samples obtained from different freshwater ecosystems in Korea could thus be a good source for isolating and investigating novel fungal species.

• 한국해양학회지
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• 제30권5호
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• pp.442-457
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• 1995

한국산 빗살거미불가사리 속의 3종, Ophiura kinbergi, O. sarsi 그리고 O, sarsi vadicola의 서식처를 파악하고, 남황해에 존재하는 생태적 장벽의 실체를 규명하기 위 하여 무기 환경요인을 이용한 서식처 지위에 관한 연구를 수행하였다. 이들의 분포를 지배하는 환경인자의 추출과정에서, 대상이 되어진 7가지 환경요소, 즉 수심, 저층 수 온, 저층 염분도, 밀도, 저층 용존산소량, 퇴적물의 평균 입도, 그리고 분급도 중 저 층 수온, 염분도 그리고 수심등이 서식처의 차이 규명에 유의한 설명력을 갖는 것으로 나타났다. 무기 환경 요소의 공간 위에서 이들 3종은 저층수의 수온와 염분도 그리고 수심 등에 대해 각기 다른 분포 범위의 폭을 나타내었다. O, sarsi vadicola를 중심으 로 한 서식처 지위의 분석에서, 우선 저층수의 염분도와 수온의 공간에서는 그 적정 서식처 범위(약 6~1$0^{\circ}C$, 31~33.5$\textperthousand$)가 황해 저층 냉수괴와 잘 일치하였으며, 수심에 대해서는 천해와 깊은 곳을 제외한 100~200m 범위에서 높은 존재 확률값이 나타났다. 한편, 본 연구에서 채집된 O. kinbergi와 O. sarsi는 O. sarsi vadicola의 적정 서식 처 범위밖에 서식하는 것으로 나타났으며, 황해산 O. sarsi vadicola의 분포 패턴에 관한 자료 분석의 결과로부터 이른바 황해에서의 저서성 무척추동물 분석의 남방 한계 선을 형성하는 생태적 장벽의 실체는 북위 33$^{\circ}$의 황해 남단에서 겨울철(12월)에 발생 하는 황해 난류(약 34$\textperthousand$<,18$^{\circ}C$)인 것으로 밝혀졌다.

• KSBB Journal
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• 제28권1호
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• pp.60-64
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• 2013

Two strains were isolated from the traditional Deep Blue Sediment Dye of Polygoum tinctoria, Niram, and temporarily named Niram A and Niram B, respectively. The phylogenetic analysis revealed that strain Niram A and B were closely related to the members of the genus Comamonas and Microbacterium, respectively. Strain Niram A exhibited the highest 16S rRNA gene sequence similarity to C. aquatica LMG $2370^T$ (98.06%). Strain Niram B showed 100% homology with M. oxydans DSM 20578T and M. maritypicum DSM $12512^T$. The growth of the strain Niram A and B was not inhibited in Niram medium containing high calcium concentration without free sugar as carbon source. The reducing Niram is greenish. Therefore, the reducing ability on the Niram of the strains Niram A and B were determined with the color difference of the $a^*$ values of Niram fermented-fluids. The $a^*$ value indicates the level of redness (positive value) or greenness (negative value). The green color is increasing towards the negative value. In all samples fermented for 10 days, the $a^*$ values among samples were no significant difference. However, samples fermented for 15 days have an appreciable change. After fermentation for 15 days, the control Niram sample had $-3.96{\pm}0.02$ of the $a^*$ value. On the other hand, the Niram samples fermented with the strain Niram A and B showed $-4.20{\pm}0.02$ of the $a^*$ value and $-7.86{\pm}0.03$ of the $a^*$ value, respectively. In the reducing ability on the Niram, the strain Niram B was significantly better than the strain Niram A.

• 미생물학회지
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• 제47권1호
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• pp.81-86
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• 2011

Xylanase는 선형복합다당인 ${\beta}$-1,4-xylan을 xylose로 가수분해하는 효소의 한 종류이며, 종이제조공정에 응용되고 미래에 바이오 연료의 생산에 사용 될 수 있다. 동해 심층 퇴적물로부터 신종세균으로 보고된 Paenibacillus donghaensis JH8은 배지중의 xylan을 분해한다고 알려져 있으며, 여기에서는 이 효소의 특성을 조사하였다. 효소는 0.1% xylan 존재에서 최고로 유도되었으며, xylanase의 생산은 초기 대수성장기에 효소를 생산하기 시작하여, 정지기에서 약 55 miliunit에 도달하였다. 세포외성 xylanase의 최적온도와 pH는 각각 $40^{\circ}C$와 pH 6.0이였다. Xylanase의 활성은 $Ca^{2+}$ 및 $Mn^{2+}$, $Fe^{2+}$, $Cu^{2+}$, $Al^{3+}$, EDTA의 존재에 의해 억제되었고, $K^+$, $Ag^+$, DTT에 의해 활성화되었다. 이 xylanase는 $40^{\circ}C$에서 120분간 활성을 유지하며 안정하였지만, $60^{\circ}C$에서는 30분에서 거의 모든 활성을 잃어버리는 특성을 보여주었다. 농축된 배양 상등액의 zymography 분석시 42 kDa의 주 밴드와 68과 120 kDa에 두 개의 아주 희미한 밴드를 나타내었다.

• 생명과학회지
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• 제27권3호
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• pp.301-309
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• 2017

본 연구는 경상남도 사천시 용정천에서 하천의 건강도와 식생 구조를 평가하기 위해 하천의 상, 주, 하류에서 물리적 구조와 30곳의 방형구에서 식물 피도를 조사하였다. 2015년 이 하천의 전체 수변식물상은 28과 72속 75종 13변종이었다. 상류 제방의 식생은 초본, 관목, 교목의 혼합 군락이었다. 상류지역의 하안단구 식생은 자연 침식으로 형성된 식물상이었다. 상류에서는 40종의 식물이 동정되었고 우점 군락은 교목이었다. 중류 지역에서 홍수터는 자연식생과 인공식생이 혼재하였다. 제외지는 초지가 우세하였다. 상, 중, 하류의 피도-풍부도(cover-abundance)는 각각 9.26, 7.24, 7.56이었다. 잎이 좁은 초본과 잎이 넓은 광엽 초본의 피도-풍부도는 유사한 비율을 나타내었다. 최근 이 지역의 하첨 주변은 상업 및 산업 시설이 설치되어 제외지 등에서 많은 하천변 식생이 훼손되었다. 따라서 이 하천의 지속 가능한 유지를 위해서는 생물종 다양성에 대한 모니터링이 필요하다고 사료된다.