• Asian-Australasian Journal of Animal Sciences
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• 제7권3호
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• pp.303-316
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• 1994

Microbial digestion of feed in the rumen involves a sequential attack culminating in the formation of fermentation products and microbial cells that can be utilized by the host animal. Most feeds are protected by a cuticular layer which is in effect a microbial barrier that must be penetrated or circumvented for digestion to proceed. Microorganisms gain access to digestible inner plant tissues through damage to the cuticle, or via natural cell openings (e.g., stomata) and commence digestion from within the feed particles. Primary colonizing bacteria adhere to specific substrates, divide to form sister cells and the resultant microcolonies release soluble substrates which attract additional microorganisms to the digestion site. These newly attracted microorganisms associate with primary colonizers to form complex multi-species consortia. Within the consortia, microorganisms combine their metabolic activities to produce the diversity of enzymes required to digest complex substrates (e.g., cellulose, starch, protein) which comprise plant tissues. Feed characteristics that inhibit the microbial processes of penetration, colonization and consortia formation can have a profound effect on the rate and extent of feed digestion in the rumen. Strategies such as feed processing or plant breeding which are aimed at manipulating feed digestion must be based on an understanding of these basic microbial processes and their concerted roles in feed digestion in the rumen.

• Journal of Microbiology and Biotechnology
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• 제9권5호
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• pp.646-649
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• 1999

A thermophilic bacterium producing D-stereospecific dipeptidase was isolated from Korean soil samples. The enzyme hydrolyzed the peptide bond between D-alanyl-D-alanine (D-Ala-D-Ala). The isolated bacterial strain was rod shaped, gram-positive, motile, and formed an endospore. Morphological and physiological characteristics suggested this microorganism a thermophilic Bacillus species, and was named as Bacillus sp. BCS-l. The production of D-stereospecific dipeptidase was growth-associated and optimal at $55^{\circ}C$. The enzyme was applied for the synthesis of D-amino acid-containing peptide, N-benzyloxycarbonyl-L-aspartyl-D-alanine benzyl ester (Z-L-Asp-D-AlaOBzl), as a model reaction. A thermodynamically controlled synthesis of Z-L-Asp-D-AlaOBzl was achieved in an organic solvent.

• 상하수도학회지
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• 제16권6호
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• pp.679-685
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• 2002

The objective of this study was investigated for the microbial community structure and treatment performance of domestic wastewater in lab-scale submerged membrane bioreactor operated with anoxic-oxic cycles. Respiratory quinone profiles were applied as tools for identifying different bacterial populations. The cycle time program of bioreactor was control under anoxic/oxic of 60/90 minutes with an hydraulic retention time of 8.4 hrs. The average $COD_{Cr}$ removal efficiency of domestic wastewater was as high as 93%. The results showed complete nitrification of $NH_4^+$-N generated during oxic period and up to 50% of the total nitrogen could be denitrified. The dominant quinone types of suspended microorganisms in bioreactor were ubiquinone (UQ)-8, -10, followed by menaquinone (MK)-6, and MK-7 for anoxic period, but those for oxic period were UQ-8, MK-6, followed by UQ-10 and MK-7. The microbial diversities of bioreactor at anoxic and oxic periods, calculated based on the composition of all quinones were 10.4 and 12.2-11.8, respectively. The experimental results showed that the microbial community structure in the submerged membrane bioreactor treating domestic wastewater was slightly affected by intermittent aeration.

• 한국지하수토양환경학회지:지하수토양환경
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• 제29권3호
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• pp.1-13
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• 2024

This study investigated the hydrogeochemical and microbiological characteristics of freshwater on Ulleung Island, a volcanic island in the Ulleung Basin on the East Coast of Korea. The shallow groundwater (CSW, NRGW) and the surface water (SISW) samples are classified as Na-HCO₃ type, reflecting an alkaline rock type and an oxidizing environment due to the influence of a highly permeable pyroclastic rock layer. In contrast, the deep groundwater sample (DMW) is classified as Ca-HCO₃ type, suggesting the influence of deep-sourced carbon dioxide and reducing conditions. Microbial communities in the water samples are generally dominated by Proteobacteria, with the relative abundance of major genera varying depending on water quality and environmental conditions. Network analysis reveals the ecological characteristics of microbial communities adapted to specific environments. The presence of pathogenic genera in the shallow groundwater suggests potential groundwater contamination, necessitating appropriate management to ensure its use as drinking water or domestic water. The findings of this study provide valuable insights into the ecological characteristics of Ulleung Island's groundwater resources and can inform future groundwater management strategies.

• Journal of Microbiology and Biotechnology
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• 제27권1호
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• pp.130-140
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• 2017

It is vital to understand the changing characteristics of interphase microbial communities and interspecies synergism during the fermentation of Chinese liquors. In this study, microbial communities in the three indispensable phases (pit mud, zaopei, and huangshui) of Luzhou-flavored liquor manufacturing pits and their shifts during cellars use were first investigated by polyphasic culture-independent approaches. The archaeal and eubacterial communities in the three phases were quantitatively assessed by combined phospholipid ether lipids/phospholipid fatty acid analysis and fluorescence in situ hybridization. In addition, qualitative information regarding the microbial community was analyzed by PCR-denaturing gradient gel electrophoresis. Results suggested that the interphase microbial community profiles were quite different, and the proportions of specific microbial groups evolved gradually. Anaerobic bacteria and gram-positive bacteria were dominant and their numbers were higher in pit mud ($10^9$ cells/g) than in huangshui ($10^7$ cells/ml) and zaopei ($10^7$ cells/g). Hydrogenotrophic methanogenic archaea were the dominant archaea, and their proportions were virtually unchanged in pit mud (around 65%), whereas they first increased and then decreased in zaopei (59%-82%-47%) and increased with pit age in huangshui (82%-92%). Interactions between microbial communities, especially between eubacteria and methanogens, played a key role in the formation of favorable niches for liquor fermentation. Furthermore, daqu (an essential saccharifying and fermentative agent) and metabolic regulation parameters greatly affected the microbial community.

• 한국초지조사료학회지
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• 제42권4호
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• pp.264-269
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• 2022

본 연구에서는 미생물 첨가에 따라 거세한우 비육우 분의 이화학적 특성, 미생물 성상, 가스발생량 및 퇴비 부숙도에 미치는 영향을 규명하고자 수행하였다. 이상의 결과를 종합하면, 4주 후, 미생물 첨가구에서 수분, 유기물, 총질소 함량 및 pH가 낮았으며, 나머지 이화학적 특성에서는 차이가 나타나지 않았다. 유산균과 효모균 수는 증가하였으며, 대장균 수는 감소하였다. 12주 후, 미생물 첨가구에서 유산균과 고초균 수는 높았으나, 수분, 효모 및 대장균 수는 낮게 낮았다. 하지만 암모니아, 황화수소 발생량과 퇴비 부숙도는 미생물 첨가에 의한 효과가 나타나지 않았다. 따라서, 거세한우 분에 미생물을 첨가하면 유익균은 증가하고, 병원성 미생물은 감소하여, 비육우의 생산성은 증진될 것으로 사료되지만, 가스 발생량 및 퇴비 부숙도에 대한 추가적인 연구는 지속적으로 수행되어야 할 것으로 사료된다.

• 생명과학회지
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• 제30권10호
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• pp.896-904
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• 2020

본 연구에서는 가축의 면역증강용 생균제 개발을 위하여 Pediococcus acidilactici SRCM102607의 프로바이오틱스 특성 및 면역활성을 조사하였다. 전통발효식품으로부터 유산균을 분리 하였고, 분리 유산균을 대상으로 가축유해 미생물 5종에 대한 항균활성을 측정하였다. 우수한 결과를 나타내는 5종의 유산균을 1차 선별하였고, 이를 대상으로 생균제 소재 활용 가능성을 확인하기 위해 용혈성, 담즙산염 분해효소, 항산화 활성 분석을 실시하여 최종적으로 SRCM102607을 선별하였으며, 16S rRNA 유전자 염기서열 분석을 통해 Pediococcus acidilactici SRCM102607로 명명하였다. SRCM102607의 pH 2 조건에서 내산성은 1.54×10⁵ CFU/ml의 생균수를 보였으며, 0.5% 이상의 oxgall이 포함된 조건에서도 10⁵ CFU/ml 이상의 높은 생균수를 나타내었다. 또한, 선발균주의 산업적으로 활용할 수 있는 가능성을 검토하기 위해 항생제 내성 및 분해 효소능을 측정하였고 다양한 항생제에 대한 내성과 유해 효소를 생성하지 않음을 확인하였고, 최종적으로 면역 증강제로서의 활용 여부를 확인하기 위해 TNF-α 생성능(171.86±4.00 ng/ml)을 확인하였다. 본 연구를 기반으로 SRCM102607은 가축 생균제 소재로 활용 가능성과 면역활성이 뛰어난 유산균으로 생균제 산업에서의 잠재적 적용 가능성을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제21권2호
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• pp.187-191
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• 2011

Microbial fuel cells (MFCs) were successfully enriched using sludge contaminated with Cr(VI) and their characteristics were investigated. After enrichment, the charge of the final 10 peaks was 0.51 C ${\pm}$ 1.16%, and the anodic electrode was found to be covered with a biofilm. The enriched MFCs removed 93% of 5 mg/l Cr(VI) and 61% of 25 mg/l Cr(VI). 16S rDNA DGGE profiles from the anodic electrode indicated that ${\beta}$-Proteobacteria, Actinobacteria, and Acinetobacter sp. dominated. This study is the first to report that electrochemically active and Cr(VI)-reducing bacteria could be enriched in the anode compartment of MFCs using Cr(VI)-containing sludge and demonstrates the Cr(VI) removal capability of such MFCs.

• Asian-Australasian Journal of Animal Sciences
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• 제16권1호
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• pp.124-135
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• 2003

In order to prevent pollution from animal waste, the excretion of nutrients should be reduced through proper nutritional management. Among the many nutrients of concern, such as N, P, Cu, Zn and K, P is one of the most concerned nutrients to be managed. Seven feeding trials, three with layers and four with broilers, were conducted to determine if microbial phytase supplementation can reduce non-phytate phosphorus (NPP) level in diets and results in concomitant reductions of P excretion. The results showed that microbial phytase can be successfully used to achieve these purposes. Activity of natural phytase in certain plant feedstuffs is high enough to be considered in feed formulation. Three experiments have been conducted to study the characteristics of plant phytase and its application to feeding of broilers. Selected brands of wheat bran could be successfully used as a source of phytase in broiler feeding.

• Archives of Pharmacal Research
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• 제10권2호
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• pp.103-109
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• 1987

To find microorganisms producing esterase inhibitors, microbes were isolated from soil samples that were collected at different locations in Korea and screened for inhibitory activities. One of the inhibitor-producing strains was named strain DMC-498. This strain was found to be a new species of the genus Streptomyces by comparison with the characteristics of morphology and metabolisms of the other species of the genus.