• The Korean Journal of Ecology
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• 제26권6호
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• pp.307-312
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• 2003

본 연구는 2000년 7월에 전남 장흥군에서 채집한 불가사리의 장내에 존재하는 종속영양세균의 다양성에 대해서 알아보았다. 불가사리 장내에 존재하는 균체수를 측정하였으며, 순수 분리된 균주를 대상으로 16S rDNA 증폭기법을 이용하여 세균의 다양성을 조사하였다. 불가사리 장내에 분포하는 종속영양세균의 균체수는 8.65${\pm}$0.65${\times}10^3\;dfu\;g^{-1}$이었다. 29 균주의 세균이 순수 분리되었으며, 그 중 그람양성 세균은 분리된 균주의 59% (17균주)를 차지하였다. 불가사리 장내에서 분리된 균주는 Bacillus속, Microbacterium 속, 그리고 Marinobacter 속 등이 우점이었으며, 이외에도 Staphylococcus 속, Psychrobacter 속, Paracoccus 속, Erythrobacter 속, Zoogloea 속, Kocuria 속과 Arthrobacter 속 등이 포함되었다. 분리된 균주 가운데 Bacillus 속에 속하는 8균주 중 3균주는 type strain과 97% 이상의 유사도를 보인 반면, 5 균주는 유사도가 90%로 비교적 낮은 유사도를 보여 현재까지 알려지지 않은 신종일 가능성이 높다고 하겠다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.489-492
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• 2000

The eventual goal of this study is to elucidate roles of plant terpenoids (e.g., cymene, limonene and others) as natural substrates in the cometabolic biodegradation of PCBs and to develop an effective PCB bioremediation technology. The aim of this study was to examine how plant terpenoids, as natural substrates or inducers would affect the biodegradation of PCB congeners. Various PCB degraders that could grow on biphenyl and several terpenoids were tested for their PCB degradation capabilities. The PCB congener degradation activities were first monitored through resting cell assay technique that could detect degradation products of the substrate. The congener removal was also confirmed by concommitant GC analysis. The PCB degraders, Pseudononas sp. P166 and Caynebacterium sp. T104 were found to grow on both biphenyl and terpenoids ((S)-(-) limonene, p-cymene and ${\alpha}-terpinene$) whereas Arthrobacter B1B could not grow on the terpenoids as a sole carbon source. The strain B1B grown on biphenyl showed a good degradation activity for 4,4'-dichlorobiphenyl (DCBp) while strains P166 and T104 gave about 25% of B1B activity. Induction of degradation by cymene, limonene and terpine was hardly detected by the resting cell assay technique. This appeared to be due to relatively lower induction effect of these terpenoids compared with biphenyl. However, a subsequent GC analysis showed that the congener could be removed up to 30% by the resting cells of T104 grown on the terpenoids. This indicates that terpenoids, widely distributed in nature, could be utilized as both growth and/or inducer substrate for PCB biodegradation.

• KSBB Journal
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• 제30권2호
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• pp.69-76
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• 2015

The antibacterial activity of a antimicrobial (organic synthetic or organic natural material) on the bacteria (Bacillus megaterium, Arthrobacter oxydans, Micrococcus luteus, Methylobacterium aquaticum) detected in the automobiles showed 99.9% bacteria decrease rate within 30 min of being in contact with the tested bacteria culture. The MIC of the organic synthetic material based antimicrobials and the organic natural material based antimicrobial on the bacteria were 31~500 mg/mL and 8~250 mg/mL, respectively. The bacteria and biofilms were formed on the surface of aluminum after 5 ~8 days in the case of addition of the organic synthetic material based antimicrobial to the MIC values for the tested bacteria culture. On the other hand, there was no proliferation of bacteria and formation of biofilms on the surface of aluminum even after 30 days in the case of addition of the organic natural material based antimicrobial to the MIC values for the tested bacteria culture. As a result, the organic natural material based antimicrobial was confirmed to be more excellent effect of inhibition of bacterial proliferation and restraint of biofilms formation than the organic synthetic material based antimicrobial.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권3호
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• pp.49-58
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• 2012

Batch experiments using indigenous and commercialized adventive microorganisms were performed to investigate the feasibility of the biodegradation process for the diesel contaminated soil, which was taken in US Military Camp 'Hialeah', Korea. TPH concentration of the soil was determined as 3,819 mg/kg. Four indigenous microorganisms having high TPH degradation activity were isolated from the soil and by 16S rRNA gene sequence analysis, they were identified as Arthrobacter sp., Burkholderia sp., Cupriavidus sp. and Bacillus sp.. Two kinds of commercialized solutions cultured with adventive microorganisms were also used for the experiments. Various biodegradation conditions such as the amount of microorganism, water content and the temperature were applied to decide the optimal bioavailability condition in the experiments. In the case of soils without additional microorganisms (on the natural attenuation condition), 35% of initial TPH was removed from the soil by inhabitant microorganisms in soil for 30 days. When the commercialized microorganism cultured solutions were added into the soil, their average TPH removal efficiencies were 64%, and 54%, respectively, which were higher than that without additional microorganisms. When indigenous microorganisms isolated from the contaminated soil were added into the soil, TPH removal efficiency increased up to 95% (for Bacillus sp.). According to the calculation of the average biodegradation rates for Bacillus sp., the remediation goal (87% of the removal efficiency: 500 mg/kg) for the soil would reach within 24 days. Results suggested that TPH removal efficiency of biodegradation by injecting indigenous microorganisms is better than those by injecting commercialized adventive microorganisms and only by using the natural attenuation.

• Journal of Microbiology and Biotechnology
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• 제15권1호
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• pp.14-21
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• 2005

By using PCR with nirS gene primers, three nirSharboring denitrifying bacteria (strain N6, strain N23, and strain R13) were newly isolated from activated sludge of a weak municipal wastewater treatment plant. Small-subunit rRNA gene-based analysis indicated that strain N6, strain N23, and strain R13 were closely related to Arthrobacter sp.,Staphylococcus sp., and Bacillus sp., respectively. In an attempt to identify their roles in biological nitrate and nitrite removal from sewage, we investigated their specific denitrification rates (SDNRs) for $NO_-^3$ - and $NO_-^2$ - in various cultures. All purecultures of each isolated nirS-harboring bacterial strain could remove $NO_-^3$ - and $NO_-^2$ - simultaneously in high efficiency, and the carbon requirements for $NO_-^3$ - removal of strain N6 and strain R13 were effectively low at 3.1 and 4.1 g COD/g $NO_3N$, respectively. In the case of mix-cultures of the strains (N6+N23, N6+R13, N23+R13, and N6+N23+R13), their SDNRs for $NO_-^3$ - were also effective, and their carbon requirements for $NO_-^3$ - removal were also effective at 3.0- 3.8 g COD/g NO3N. However, all tested mix-cultures accumulated $NO_-^2$ - in their culture media. On the other hand, the continuous culture of activated sludge mixed with strain N6 showed no significant increase of $NO_-^3$ - removal in comparison with strain N6's pure culture. These results suggest that nitrate and nitrite removal in biological wastewater treatment might be dependent on complicated bacterial interactions, including several effective denitrifying bacteria isolated in this study, rather than the specific bacterial types present and the number of bacterial types in activated sludge.

• Journal of Microbiology and Biotechnology
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• 제17권4호
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• pp.560-570
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• 2007

The effective and accurate assessment of the total microbial community diversity is one of the primary challenges in modem microbial ecology, especially for the detection and characterization of unculturable populations and populations with a low abundance. Accordingly, this study was undertaken to investigate the diversity of the microbial community during the biodegradation of cis- and trans-dichloroethenes in soil and wastewater enrichment cultures. Community profiling using PCR targeting the l6S rRNA gene and denaturing gradient gel electrophoresis (PCR-DGGE) revealed an alteration in the bacterial community profiles with time. Exposure to cis- and trans-dichloroethenes led to the disappearance of certain genospecies that were initially observed in the untreated samples. A cluster analysis of the bacterial DGGE community profiles at various sampling times during the degradation process indicated that the community profile became stable after day 10 of the enrichment. DNA sequencing and phylogenetic analysis of selected DGGE bands revealed that the genera Acinetobacter, Pseudomonas, Bacillus, Comamonas, and Arthrobacter, plus several other important uncultured bacterial phylotypes, dominated the enrichment cultures. Thus, the identified dominant phylotypes may play an important role in the degradation of cis- and trans-dichloroethenes.

• Journal of Microbiology and Biotechnology
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• 제20권11호
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• pp.1577-1584
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• 2010

In total, 140 halotolerant bacterial strains were isolated from both the soil of barren fields and the rhizosphere of six naturally growing halophytic plants in the vicinity of the Yellow Sea, near the city of Incheon in the Republic of Korea. All of these strains were characterized for multiple plant growth promoting traits, such as the production of indole acetic acid (IAA), nitrogen fixation, phosphorus (P) and zinc (Zn) solubilization, thiosulfate ($S_2O_3$) oxidation, the production of ammonia ($NH_3$), and the production of extracellular hydrolytic enzymes such as protease, chitinase, pectinase, cellulase, and lipase under in vitro conditions. From the original 140 strains tested, on the basis of the latter tests for plant growth promotional activity, 36 were selected for further examination. These 36 halotolerant bacterial strains were then tested for 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity. Twenty-five of these were found to be positive, and to be exhibiting significantly varying levels of activity. 16S rRNA gene sequencing analyses of the 36 halotolerant strains showed that they belong to 10 different bacterial genera: Bacillus, Brevibacterium, Planococcus, Zhihengliuella, Halomonas, Exiguobacterium, Oceanimonas, Corynebacterium, Arthrobacter, and Micrococcus. Inoculation of the 14 halotolerant bacterial strains to ameliorate salt stress (150 mM NaCl) in canola plants produced an increase in root length of between 5.2% and 47.8%, and dry weight of between 16.2% and 43%, in comparison with the uninoculated positive controls. In particular, three of the bacteria, Brevibacterium epidermidis RS15, Micrococcus yunnanensis RS222, and Bacillus aryabhattai RS341, all showed more than 40% increase in root elongation and dry weight when compared with uninoculated salt-stressed canola seedlings. These results indicate that certain halotolerant bacteria, isolated from coastal soils, have a real potential to enhance plant growth under saline stress, through the reduction of ethylene production via ACC deaminase activity.

• 환경생물
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• 제38권3호
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• pp.433-449
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• 2020

Nine fish and one clam species were collected from freshwater environments in Korea, including four lakes, two streams, and the Nakdong River, to investigate the host-associated bacteria. Hundreds of bacterial strains were isolated from the samples using a cell sorter and a dilution plating method. After identification of the bacterial strains using 16S rRNA gene sequences, 42 strains with greater than 98.7% sequence similarity with validly published species were determined to be unrecorded bacterial species in Korea. These strains were phylogenetically diverse and assigned to four phyla, six classes, 17 orders, 27 families, and 32 genera. At the genus level, the unrecorded species were classified as Corynebacterium, Mycobacterium, Mycolicibacterium, Gordonia, Williamsia, Modestobacter, Brachybacterium, Sanquibacter, Arthrobacter, and Mycolicibacterium of the class Actinobacteria; Empedobacter, and Flavobacterium of the class Flavobacteriia; Fictibacillus, Psychrobacillus, Cohnella, Paenibacillus, Rummeliibacillus, Enterococcus, and Vagococcus of the class Bacilli; Aquamicrobium, Paracoccus, and Sphingomonas of the class Alphaproteobacteria; Achromobacter, Delftia, and Deefgea of the class Betaproteobacteria; and Aeromonas, Providencia, Yersinia, Marinomonas, Acinetobacter, and Pseudomonas of the class Gammaproteobacteria. The 42 unrecorded species were subjected to further taxonomic characterization using gram staining, cellular and colony morphological determination, biochemical analyses, and phylogenetic analyses. This paper provides detailed descriptions of the 42 previously unrecorded bacterial species.

• Journal of Species Research
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• 제9권4호
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• pp.362-374
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• 2020

A total of 35 bacterial strains were isolated from various sediment samples. From 16S rRNA gene sequence similarities higher than 98.7% and the formation of a robust phylogenetic clade with the closest species, it was determined that each strain belonged to independent and predefined bacterial species. No previous official reports have described these 35 species in Korea. The unrecorded species were assigned to 6 phyla, 10 classes, 18 orders, 23 families, and 31 genera. At the genus level, the unrecorded species were affiliated with Terriglobus of the phylum Acidobacteria, as well as with Mycobacterium, Rhodococcus, Kineococcus, Phycicoccus, Agromyces, Cryobacterium, Microbacterium, and Arthrobacter; Catellatospora of the class Actinomycetia; Lacibacter of the class Chitinophagia; Algoriphagus and Flectobacillus of the class Cytophagia; Flavobacterium and Maribacter of the class Flavobacteriia; Bacillus, Cohnella, Fontibacillus, Paenibacillus, Lysynibacillus, and Paenisporosarcina of the class Bacilli; Bradyrhizobium, Gemmobacter, Loktanella, and Altererythrobacter of the class Alphaproteobacteria; Acidovorax of the class Betaproteobacteria; Aliiglaciecola, Cellvibrio, Arenimonas, and Lysobacter of class Gammaproteobacteria; and Roseimicrobium of the class Verrucomicrobia. The selected strains were subjected to further taxonomic characterization, including Gram reaction, cellular and colonial morphology, and biochemical properties. This paper provides detailed descriptions of the 35 previously unrecorded bacterial species.

• 미생물학회지
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• 제36권3호
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• pp.167-172
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• 2000

제주도의 여섯 지역과 인천 작약도 근해의 해수로부터 내염성 그람양성 세균 25균주를 분리하여 화학 분류학적 특징과 표현형적 특성을 조사하였다. 분리된 균주들은 화학 분류학적 특징에 의거하여 4개의 group으로 구분되었다. Group1은 40.~49.9 mol% 의 G+C함량과 MK-7의 menaquinome type, peptidoglycan의 주요 아미노산으로 meso-A2pm을 함유하며 Bacillus pumilus와 Bacillus licheniformis, Bacillu megaterium, bacillus subtilis로 동정되었으며, Group 2는 63.9~66.4 mol% 의 G+C 함량과 MK-8을 함유하는 Arthrobacter속 세균이었으며 , Group 3은 31.0~37.6 mol%의 G+G 함량과 MK-7을 함유하며 Staphylococcus haemolyticus, Staphylococcus saprophyticyus, Staphylococcus intermedius 로 , Group 4는 72.0 mol% 의 G+C 함량과 MK-8을 주요 quinone으로 함유하는 Micrococcus luteus로 동정되었다. 분리된 세균들 중 Bacillus 속 세균들은 68%로 우세한 분포를 나타내었다.