• 생명과학회지
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• 제24권6호
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• pp.694-699
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• 2014

토착 미생물은 친환경적 정화에 중요한 역할을 한다. 원유(crude oil)를 분해하는 80균주를 인천 연안에서 분리하고 oil film collapsing방법을 이용하여 유화능이 있는 12균주를 선별하였다. 이들 균주에 대해 ${\rho}$-nitrophenyl butylrate를 기질로 이용하여 리파아제(lipase)활성과 n-hexanedecane을 기질로 이용하여 유화(emulsification)활성을 측정하여 원유 분해 활성이 좋은 Incheon9를 선별하고 gas chromatography (FID)로 paraffine계 탄화수소를 감소시키는 것을 확인하였다. 이 균주의 16s rRNA유전자 분석을 통해 Acinetobacter sp.로 동정하고 NCBI에 등록하여 accession code (KF548540)를 부여 받았다. Acinetobacter sp. Incheon9의 성장과 유화능이 최적 배양 조건은 $20^{\circ}C$, pH 7, 1% NaCl였으며 대수증식기 기간에 가장 높은 유화능을 보였으며 탄화수소가 짧은 trybutyrin에서 분해능력이 좋았다. 이번 연구결과는 환경오염에 활용 가능한 미생물자원군의 확보를 위한 연구였으며 추후 활용을 위해서는 실제 환경에서 동일한 활성을 가지는지 여부에 대한 연구가 추가로 진행되어야 할 것이다.

• 미생물학회지
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• 제52권2호
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• pp.183-191
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• 2016

유기산을 생산하는 발효미생물을 획득하기 위해 갯벌, 심해, 염전 등의 퇴적토와 해초시료 등의 시료에 대해 methanogen 배지, acetogen 배지, Clostridium용 배지 등을 이용하여 농후 배양을 실시하였다. 총 8개 시료로부터 65주의 혐기성 미생물을 분리하였으며 이 중 신규성이 높거나 활용성이 높다고 알려진 11종에 대해 계통분석, 성장 양식(growth pattern), 유기산 생산 평가 등을 시도하였다. 분석이 수행된 균주 중 Bacteroidia 강에 속하는 1주 외에는 모두 Clostridia 강에 속하였으며 성장속도는 $1.2h^{-1}$ 이상이었다. 분석이 수행된 7종 중 6종은 아세트산을 생성하였으며, 부가적으로 2균주는 부틸산을, 4균주는 개미산을 생산하였다. 또한 MCWD5 균주는 제공된 포도당의 약 40%를 세포외 고분자물질로 전환시키는 것으로 나타났다. 본 연구를 통하여 국내 연안해역에서 분리된 신규 혐기성 미생물들은 유기산, 고분자 다당류를 생산하는 등 높은 응용성을 지님을 확인할 수 있었다.

• 한국환경과학회지
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• 제19권10호
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• pp.1307-1314
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• 2010

This study was conducted to isolate and characterize a novel feather-degrading bacterium producing keratinase activity. A strain K9 was isolated from soil at poultry farm and identified as Xanthomonas sp. K9 by phenotypic characters and 16S rRNA gene analysis. The cultural conditions for the keratinase production were 0.3% fructose, 0.1% gelatin, 0.04% $K_2HPO_4$, 0.06% $KH_2PO_4$, 0.05% NaCl and 0.01% $FeSO_4$ with an initial pH 8.0 at $30^{\circ}C$ and 200 rpm. In an optimized medium containing 0.1% chicken feather, production yield of keratinase was approximately 8-fold higher than the yield in basal medium. The strain K9 effectively degraded chicken feather meal (67%) and duck feather (54%), whereas human nail and human hair showed relatively low degradation rates (13-22%). Total free amino acid concentration in the cell-free supernatant was about 25.799 mg/l. Feather hydrolysate produced by the strain K9 stimulated growth of red pepper, indicating Xanthomonas sp. K9 could be not only used to increase the nutritional value of chicken feather but also a potential candidate for the development of natural fertilizer applicable to crop plant soil.

• 한국환경과학회지
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• 제29권5호
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• pp.435-443
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• 2020

The purpose of this study was to investigate eco-friendly measures to manage major diseases which cause heavy economic damages to ginseng. Morphological, physicochemical, and molecular biological species identification was carried out after isolating useful antagonistic bacteria from ginseng fields. In addition, optimal conditions for mass culture were established, and he efficacy of the bacteria in the prevention of the diseases was verified in the field. The results showed that about 150 bacteria were extracted from 150 ginseng fields in the whole county. Among them, B. pyrrocinia LA101 was finally selected, which had a strong antagonistic potency against Alternaria panax, Botrytis cinerea, Rhizoctonia solani, and Cylindrocarpon destructans on agar media. The B. pyrrocinia LA101 is a baculiform gram-negative bacterium identified as Burkholderia pyrrocinia according to results from an API(Analytical Profile Index) kit, 16S rRNA, and gyrase gene sequencing analysis. It was donated to the microbe bank of the Agricultural Genetic Resources Center at the National Academy of Agriculture Science under the Rural Development Administration on September 28, 2011 (Donation No. KACC91663P). A patent for the mass culture technology was granted in August 2012 (Patent No. 10-1175532).

• KSBB Journal
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• 제26권2호
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• pp.100-106
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• 2011

Strain BCNU 5011 was isolated from forest soil samples collected in the Taebaek mountain in the Gangwon province, Korea. The biochemical, physiological and 16S rRNA sequence analysis strongly indicated that this isolate was most closely related to Paenibacillus polymyxa. A maximum production level of antimicrobial substances of Paenibacillus sp. BCNU 5011 was achieved under aerobic incubation at $30^{\circ}C$ for 3 days in SST broth.Paenibacillus sp. BCNU 5011 showed a broad spectrum of activity against Gram positive and Gram negative bacteria, including methicllinresistant Staphylococcus aureus (MRSA). Paenibacillus sp. BCNU 5011 was also shown to inhibit the growth of different potential human pathogenic bacteria and fungi in vitro. Peptide extract showed better antimicrobial activity than solvent extracts. But active antimicrobial compounds might be included in both peptide extract and solvent extracts. Further separation, purification and identification of active principles leads project to develop antimicrobial agents and anti-MRSA agents.

• 한국식품영양과학회지
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• 제38권4호
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• pp.509-516
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• 2009

메주로부터 곰팡이 및 세균 등에 생육 저해활성을 나타내는 균주 B. polyfermenticus CJ6을 분리 동정하였다. 분리 균주 B. polyfermenticus CJ6는 2단 대수기를 나타내는 생육 곡선상 특이점을 나타내었으며 배양 30시간 이후부터 최대 활성을 나타내었고 사멸기 이후 활성이 다소 감소되었으나 120시간까지 활성을 유지하였다. B. polyfermenticus CJ6의 항진균 활성 물질은 $70^{\circ}C$ 이상에서 활성이 감소되었으나 $121^{\circ}C$에서 15분간 열처리 시 역가가 완전히 소실되지 않았다. pH 안정성 실험에서는 pH $3.0{\sim}9.0$ 구간에서 안정한 활성을 나타내었으며, 각종 효소에 대한 영향에서 항진균 활성물질은 proteinase K, protease, ${\alpha}$-chymotrypsin 등의 단백분해효소 처리로 역가를 상실하거나 일부 감소되어 단백질성 물질임을 추정하였다. 균주의 항진균 활성 물질을 $C_{18}$ Sep-Pak column으로 부분 정제한 후 Tricine-SDS-PAGE 및 direct detection 실험을 통하여 분자량이 약 1.4 kDa의 물질임을 확인하였다. B. polyfermenticus CJ6가 생산하는 항진균 활성 물질은 기존에 거의 보고되지 않은 B. polyfermenticus 유래의 단백질성 항진균 활성 물질로서 천연보존제 및 천연항균제재로 사용이 기대되며, 이를 위하여 항진균 활성 물질들의 정제 및 구조분석 등의 연구가 필요하다.

• Journal of Microbiology and Biotechnology
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• 제9권5호
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• pp.631-636
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• 1999

The thermostable endo-chitosanase gene from the isolated strain Bacillus sp. KFB-C108 was identified on the basis of a phylogenetic analysis of the 16S rRNA gene sequence, and was cloned into plasmid pUCl8 using E. coli $DH5\alpha$ as the host strain. Positive clones carrying recombinant plasmids (pKCHO I and pKCHO II) containing chitosanase activity were selected using the direct activity staining method. Detailed physical maps showed the two plasmid inserts were identical except that the KCHO II insert (2.6 kb) was 1.8 kb smaller than that of the KCHO I. The recombinant plasmids were analyzed to determine the essential region for chitosanase activity, and a 1.3-kb fragment (KCHO-6) was subcloned into pTrc99A using the EcoRI and BamHI sites to construct pTrc99A/KCHO-6(pTrEB13). The resulting plasmid exerted high chitosanase activity upon transformation of E. coli $DH5{\alpha}cells$, overproducing about 20 times more in the cloned cells than in the wild-type cells. The cloned chitosanase protein exhibited the same molecular weight and catalytic activity similar to those of Bacillus sp. KFB-C108. The cloned enzyme was an endo-type that produced a chitosan tetramer as the major reaction product; however, it produced no monomers or dimers.

• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.784-791
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• 2007

The present work aims to use a biofilter technology(aerated submerged filters) for the aerobic transformation at laboratory-scale of olive washing water(OWW) generated in the first steps of olive oil processing, as well as the genetic profiling and identification to the species level of the bacteria involved in the formation of the biofilm, by means of TGGE. Chemical parameters, such as biological oxygen demand at five days($BOD_5$) and chemical oxygen demand(COD), decreased markedly(up to 90 and 85%, respectively) by the biological treatment, and the efficiency of the process was significantly affected by aeration and inlet flow rates. The total polyphenol content of inlet OWW was only moderately reduced(around 50% decrease of the inlet content) after the biofilter treatment, under the conditions tested. Partial 16S rRNA genes were amplified using total DNA extracted from the biofilm and separated by TGGE. Sequences of isolated bands were mostly affiliated to the $\alpha-subclass$ of Proteobacteria, and often branched in the periphery of bacteria] genera commonly present in soil(Rhizobium, Reichenowia, Agrobacterium, and Sphingomonas). The data obtained by the experimentation at laboratory scale provided results that support the suitability of the submerged filter technology for the treatment of olive washing waters with the purpose of its reutilization.

• Journal of Microbiology and Biotechnology
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• 제25권8호
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• pp.1349-1360
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• 2015

The rhizospheric zone abutting plant roots usually clutches a wealth of microbes. In the recent past, enormous genetic resources have been excavated with potential applications in host plant interaction and ancillary aspects. Two Pseudomonas strains were isolated and identified through 16S rRNA and rpoD sequence analyses as P. fluorescens QAU67 and P. putida QAU90. Initial biochemical characterization and their root-colonizing traits indicated their potential role in plant growth promotion. Such aerobic systems, involved in gluconic acid production and phosphate solubilization, essentially require the pyrroloquinoline quinine (PQQ)-dependent glucose dehydrogenase (GDH) in the genome. The PCR screening and amplification of GDH and PQQ and subsequent induction of mutagenesis characterized their possible role as antioxidants as well as in growth promotion, as probed in vitro in lettuce and in vivo in rice, bean, and tomato plants. The results showed significant differences (p ≤ 0.05) in parameters of plant height, fresh weight, and dry weight, etc., deciphering a clear and in fact complementary role of GDH and PQQ in plant growth promotion. Our study not only provides direct evidence of the in vivo role of GDH and PQQ in host plants but also reveals their functional inadequacy in the event of mutation at either of these loci.

• Journal of Microbiology and Biotechnology
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• 제18권5호
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• pp.805-814
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• 2008

Liming of acidic soils can prevent aluminum toxicity and improve crop production. Some maize lines show aluminum (Al) tolerance, and exudation of organic acids by roots has been considered to represent an important mechanism involved in the tolerance. However, there is no information about the impact of liming on the structures of bacterial and fungal communities in Cerrado soil, nor if there are differences between the microbial communities from the rhizospheres of Al-tolerant and Al-sensitive maize lines. This study evaluated the effects of liming on the structure of bacterial and fungal communities in bulk soil and rhizospheres of Al-sensitive and Al-tolerant maize (Zea mays L.) lines cultivated in Cerrado soil by PCR-DGGE, 30 and 90 days after sowing. Bacterial fingerprints revealed that the bacterial communities from rhizospheres were more affected by aluminum stress in soil than by the maize line (Al-sensitive or Al-tolerant). Differences in bacterial communities were also observed over time (30 and 90 days after sowing), and these occurred mainly in the Actinobacteria. Conversely, fungal communities from the rhizosphere were weakly affected either by liming or by the rhizosphere, as observed from the DGGE profiles. Furthermore, only a few differences were observed in the DGGE profiles of the fungal populations during plant development when compared with bacterial communities. Cloning and sequencing of 16S rRNA gene fragments obtained from dominant DGGE bands detected in the bacterial profiles of the Cerrado bulk soil revealed that Actinomycetales and Rhizobiales were among the dominant ribotypes.