• Journal of Microbiology and Biotechnology
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• 제24권1호
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• pp.13-18
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• 2014

Bacillus subtilis JW-1 was isolated from rhizosphere soil as a potential biocontrol agent of bacterial wilt caused by Ralstonia solanacearum. Seed treatment followed by a soil drench application with this strain resulted in >80% reduction in bacterial wilt disease compared with that in the untreated control under greenhouse conditions. The antibacterial compound produced by strain JW-1 was purified by bioactivity-guided fractionation. Based on mass spectroscopy and nuclear magnetic resonance spectral data ($^1H$, $^{13}C$, $^1H-^1H$ correlation spectroscopies, rotating frame nuclear Overhauser effect spectroscopy, and heteronuclear multiple-bond correlation spectroscopy), the structure of this compound was elucidated as a cyclic lipopeptide composed of a heptapeptide (Gln-Leu-Leu-Val-Asp-Leu-Leu) bonded to a ${\beta}$-hydroxy-iso-hexadecanoic acid arranged in a lactone ring system.

• Mycobiology
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• 제51권5호
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• pp.320-332
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• 2023

Talaromyces is a genus within the phylum Ascomycota (class Eurotiomycetes, order Eurotiales, family Trichocomaceae). Many species in this genus are known to produce diverse secondary metabolites with great potential for agricultural, medical, and pharmaceutical applications. During a survey on fungal diversity in the genus Talaromyces in Korea, six strains were isolated from soil, indoor air, and freshwater environments. Based on morphological, physiological, and multi-locus (ITS, BenA, CaM, and RPB2) phylogenetic analyses, we identified five previously unrecorded species in Korea (T. brevis, T. fusiformis, T. muroii, T. ruber, and T. soli) and a new species (T. echinulatus sp. nov.) belonging to section Talaromyces. Herein, detailed descriptions, illustrations, and phylogenetic tree are provided.

• 한국미생물·생명공학회지
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• 제51권3호
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• pp.303-305
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• 2023

In this study, we report the complete genome sequence of Priestia megaterium strain HyangYak-01, which was isolated from the rhizosphere soil of Centella asiatica. The genome consists of 5,086,279 bp of sequences with 38.2 percent GC content and 5,111 coding genes. The genome contains several important genes related to plant growth-promoting activities, which were also confirmed with in vitro media assays.

• Journal of Microbiology and Biotechnology
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• 제24권1호
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• pp.80-86
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• 2014

Tannase (Tan410) from a soil metagenomic library was immobilized on different supports, including mesoporous silica SBA-15, chitosan, calcium alginate, and amberlite IRC 50. Entrapment in calcium alginate beads was comparatively found to be the best method and was further characterized. The optimum pH of the immobilized Tan410 was shifted toward neutrality compared with the free enzyme (from pH 6.4 to pH 7.0). The optimum temperature was determined to be $45^{\circ}C$ for the immobilized enzyme and $30^{\circ}C$ for the free enzyme, respectively. The immobilized enzyme had no loss of activity after 10 cycles, and retained more than 90% of its original activity after storage for 30 days. After immobilization, the enzyme activity was only slightly affected by $Hg^{2+}$, which completely inhibited the activity of the free enzyme. The immobilized tannase was used to remove 80% of tannins from a green tea infusion on the first treatment. The beads were used for six successive runs resulting in overall hydrolysis of 56% of the tannins.

• Journal of Microbiology
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• 제39권2호
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• pp.139-141
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• 2001

Medium-chain length polyhydrexyalkanoic acids (MCL-PHAs) degrading bacterium was isolated from the soil. The bacterium was identified as Janthinobacterium lividum by its biochemical properties, cell membrane fatty acids composition, and 16S rDNA sequence analysis. The bacterium showed a similarity of 0.911 with J. lividum according to the cell membrane fatty acids analysis and a similarity of 97% in the 16S rDNA requence analysis. Culture supernatant of the bacterium skewed the highest depolymerase activity toward polyhydroxynonanoic acid (PHN) that did not degrade the poly-$\beta$-hydroxybutyric acid (PHB). The esterase activity was also detected with p-nitrophenyl (PNP) esters of fatty acids such as PNP-dodecanoic PNP-dodecanoic acid, PNP-decanoic acid, and PNP-hexanoic acid.

• Journal of Microbiology and Biotechnology
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• 제7권2호
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• pp.121-126
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• 1997

A bacterial strain LC-413, producing an extracellular inulin fructotransferase (depolymerizing) which converts inulin into di-D-fructofuranose dianhydride (DFAIII), was isolated from soil. Inulin fructotransferase from the isolate identified as a strain Flabobacterium sp. was purified from the culture broth by ammonium sulfate precipitation, followed by column chromatograpies on DEAE-Toyopearl 650 M and phenyl-Toyopearl 650 M. The purified enzyme gave a single band on an electrophoretic disc-gel. The molecular weight of the enzyme was estimated to be 44, 000 Da by SDS-polyacrylamide gel electrophoresis, and 45, 000 Da by gel filtration, suggesting the monomeric state of the enzyme. The isoelectric point of the enzyme was about pH 4.5. The optimal pH and temperature for the enzyme reaction were 6.0 and $50^{\circ}C$, respectively. The purified enzyme digested inulin into di-D-fructofuranose-l, 2': 2, 3'-dianhydride, confirming the enzyme was an inulin fructotransferase (inulinase II).

• 한국미생물·생명공학회지
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• 제38권3호
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• pp.329-334
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• 2010

본 연구에서는 유류 분해능이 있고 식물 성장 촉진능력을 가진 Gordonia sp. S2RP-17, 중금속에 내성을 가지며 식물 성장촉진 능력이 있는 Serratia sp. SY5 및 옥수수를 이용하여 유류 및 중금속 오염 토양의 정화 특성을 조사하였다. 유류 및 중금속 오염 토양에서 51일간 재배한 옥수수의 평균 뿌리 건중량은 $1.9{\pm}0.2\;g$이었으나, 근권세균을 접종한 오염 토양에서 재배한 옥수수의 뿌리 건중량은 $5.6{\pm}0.7\;g$로, 근권세균 접종에 의해 옥수수의 뿌리의 중량이 유의적으로 증가함을 알 수 있었다(p<0.01). 초기에는 토양의 TPH 농도는 $21,576{\pm}3,426\;mg-TPH{\cdot}kg-dry\;soil^{-1}$이었는데, 51일 후 옥수수만을 식재한 토양의 잔류 TPH 농도는 $220{\pm}98\;mg-TPH{\cdot}kg-dry\;soil^{-1}$이었고, 옥수수와 함께 근권세균을 접종한 토양의 잔류 TPH 농도는 $20{\pm}41\;mg-TPH{\cdot}kg-dry\;soil^{-1}$이었다. 이러한 결과로부터 옥수수 식재에 의해 대부분의 TPH를 제거할 수 있으며, 옥수수와 함께 근권세균을 접종하면 TPH 효율이 조금 더 향상됨을 알 수 있었다. 그러나, 중금속 제거효율에 미치는 근권세균 접종 효과는 거의 없었다.

• Journal of Microbiology and Biotechnology
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• 제2권1호
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• pp.66-71
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• 1992

The ecological distribution of endomycorrhizas in evergreen woody species native to the evergreen forest ecosystem of Tadohae-haesang National Park in southern Korea in February, 1989 was studied. The abundance and diversity of vesicular-arbuscular (VA) mycorrhizal fungi were also determined. The spore densities ranged from 14 to 326 per 100 g of soil. Most of the spores of mycorrhizal fungi collected from 25 soil samples belonged to the genera Glomus and Gigaspora. The frequency and number of spores in Camellia japonica varied with location. Spores belonging to the genus Gigaspora were not found in Camellia japonica in Yesongri evergreen forests adjacent to the sea. Glomus sp. was the major constituent of the spore assemblage at this site. The most abundant species in Camellia japonica in the Yesongri evergreen forests in Pogildo was Glomus borealis. In the soil of a mountain at Buwhangri, in the central location of the island at an elevation of 250 m, Gigaspora sp. was present and Glomus sp. was a major constituent of the spore assemblage. In the urban area of Haenam spore densities were much higher than in the Pogildo area. The most abundant species in Camellia japonica in the urban area of Haenam was Gigaspora sp..

• Journal of Microbiology and Biotechnology
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• 제18권9호
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• pp.1496-1499
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• 2008

A Gram-negative, aerobic, rod-shaped, nonspore-forming bacterial strain, designated Gsoil $357^T$ was isolated from soil sample of a ginseng field in Pocheon Province (South Korea). The isolate contained Q-8 as the predominant ubiquinone and iso-$C_{16:0}$, iso-$C_{17:1}$ ${\omega}9c$, and iso-$C_{15:0}$ as the major fatty acids. The G+C content of the genomic DNA was 69.3 mol%. A phylogenetic analysis based on 16S rRNA gene sequences revealed that strain Gsoil $357^T$ was most closely related to Lysobacter gummosus (97.6%) and Lysobacter antibioticus (97.6%). However, the DNA-DNA relatedness value between strain Gsoil $357^T$ and its phylogenetically closest neighbors was less than 17%. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain Gsoil 357T should be classified as representing a novel species in the genus Lysobacter, for which the name Lysobacter ginsengisoli sp. novo is proposed. The type strain is Gsoil $357^T$ (=KCTC $12602^T$=DSM $18420^T$).

• Journal of Microbiology and Biotechnology
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• 제16권1호
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• pp.153-157
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• 2006

A soil metagenomic library was constructed using an E. coli-fosmid cloning system with environmental DNAs extracted from Kwangreung forest topsoil. We targeted the genes involved in the biosynthesis of bacterial polyketides. Initially, a total of 36 clone pools (10,800 clones) were explored by the PCR-based method using the metagenomic DNAs from each pool and a degenerate primer set, which has been designed based on the highly conserved regions among ketoacyl synthase (KS) domains in actinomycete type I polyketide synthases (PKS Is). Six clone pools were tentatively selected as positive and further examined through a hybridization-based method for selecting a fosmid clone containing PKS I genes. Colony hybridization was performed against fosmid clones from the 6 positive pools, and finally 4 clones were picked out and confirmed to contain the conserved DNA fragment of KS domains. In this study, we present a simple and feasible sorting method for a desired clone from metagenomic libraries.