• Korean Journal of Environmental Agriculture
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• v.30 no.4
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• pp.424-431
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• 2011

BACKGROUND: Tributyltin chloride is among the most toxic compounds known for aquatic ecosystems. Microorganisms are responsible for removal of TBTCl. Nevertheless, only a limited number of marine bacteria were investigated for biodegradation of TBTCl in Korea. METHODS AND RESULTS: The number of TBTCl resistant bacteria ranged from $2.5{\times}10^3$ to $3.8{\times}10^3$ cfu/mL in the seawater, and ranged from $3.2{\times}10^5$ to $9.1{\times}10^5$ cfu/g in the surface sediment, respectively. The morphological, physiological, and biochemical characteristics of TBTCl resistant bacteria were investigated by API 20NE and other tests. The most abundant species of TBTCl resistant bacteria were Vibrio spp. (19.2%), Bacillus spp. (16.2%), Aeromonas spp. (15.2%), and Pseudomonas spp. (13.1%), etc. Eleven TBTCl resistant isolates also had a resistance to heavy metals (Cd, Cu, Hg, and Zn). Among them, isolate T7 showing the strong TBTCl-resistance was selected. This isolate was identified as the genus Pantoea by 16S rRNA gene sequencing and designated as Pantoea sp. T7. In addition, this bacterium was cultivated up to the growth of 50.7% after 60 hrs at TBTCl concentration of $500{\mu}M$. TBTCl-degrading activity of Pantoea sp. T7 was measured by GC-FPD analysis. As a result of biological TBTCl-degradation at TBTCl concentration of $100{\mu}M$, TBTCl-removal efficiency of Pantoeasp. T7 was 62.7% after 40 hrs. CONCLUSION(S): These results suggest that Pantoea sp. T7 is potentially useful for the bioremediation of TBT contamination.

• Korean Journal of Microbiology
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• v.34 no.4
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• pp.200-206
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• 1998

The distributions and characteristics of bacteria on the deodorizing biofilters were studied as a part of biofiltration research for odor gas removal. The odor gas originated from a currently operating nightsoil treatment plant were mainly nitrogenous compounds of ammonia and amines. The filter media were consisted various ratio of pine bark, nightsoil cast and compost, and were sampled before and after operation of 153 days. Before operation, the level of bacteria on nitrification agar medium, nutrient agar medium and thiosulfate agar medium were around $10^7{\sim}10^8cfu/g$ media. After operation, the level decreased but still high as $10^5{\sim}10^7cfu/g$ media. The bacteria from reactors before and after operations were either rod or coccus after growth on nitrification agar media. The 45 isolated heterotrophic bacteria were further characterized and Pseudomonas, Bacillus, Flavobacterium, Alcaligenes were dominant genera. Genus Alcaligenes was particularly dominant when the isolates were incubated on nitrification agar media first and then transfered to nutrient media. The portion of Alcaligenes in the biofilter increased after operation, and was higher in the media contained nightsoil cast, which showed better treatment than the media with pine bark only.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1169-1175
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• 2011

The soil chemical properties, microbial community structures and biochemical properties of lettuce or cucumber-cultivated greenhouse soil samples were analyzed to assess soil health and characterize microbial distribution in 8 locations in Korea. Although most of chemical properties were within the soil management guidelines, the available phosphate, and the contents of exchangeable potassium and calcium were higher than those of recommended levels. In the culture-dependent analysis, 841 bacterial strains were isolated from the greenhouse soils and were identified at the genus level by 16S rRNA gene sequences analysis. The dominant bacterial genera were Bacillus (35.7%), Microbacterium (9.3%), Arthrobacter (5.7%) and Lysobacter (5.1%). The abundance of pseudomonads was highly variable depending on the soil samples. In the culture-independent analysis, soil microbial community was investigated by using phospholipid fatty acid (PLFA) method. Principal component analysis (PCA) showed that a specific grouping for microbial community structure in the greenhouse soils was not observed based on cultivated crops and investigated sites. The results revealed that the greenhouses soils examined are relatively sound managed in terms of soil chemical contents and microbial properties.

• Journal of Life Science
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• v.31 no.7
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• pp.641-653
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• 2021

The purpose of this study was to confirm the antifungal activity, plant growth-promoting activity, and mineral solubilizing activity of 18 types of bacteria isolated purely from rhizosphere soil. The potential of isolates of the genus Bacillus and Pseudomonas as biocontrol agents was confirmed through the antifungal activity of these isolates. This activity has been determined to be due to various hydrolytic enzymes on the cell wall of plant pathogenic fungi and the production of siderophores in isolates. In addition, most of the isolates have been found to have aminocyclopropane-1-carboxylate deaminase production activity, indole-3-acetic acid production activity, and nitrogen fixation activity. These characteristics are believed to have a positive effect on root development, growth, and the productivity of crops via a reduction in the concentration of ethylene under conditions of environmental stress, to which plants are commonly exposed. In addition, on testing for the solubilizing activity of the isolates for phosphoric acid, silicon, calcium carbonate, and zinc, some isolates were found to have mineral solubilizing activities. Inoculation of these isolates during plant growth is expected to assist plant growth by converting nutrients necessary for growth into usable forms that can be absorbed by plants. The 18 isolated strains can be used as biocontrol agents due to their antifungal activity, plant growthpromoting activity, and mineral solubilizing activity.

• Journal of Microbiology and Biotechnology
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• v.21 no.6
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• pp.545-555
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• 2011

The diversity elucidation by amplified ribosomal DNA restriction analysis and 16S rDNA sequencing of 96 associative diazotrophs, isolated from the feeder roots of tea on enriched nitrogen-free semisolid media, revealed the predominance of Gram-positive over Gram-negative bacteria within the Kangra valley in Himachal Pradesh, India. The Gram-positive bacteria observed belong to two taxonomic groupings; Firmicutes, including the genera Bacillus and Paenibacillus; and Actinobacteria, represented by the genus Microbacterium. The Gram-negative bacteria included ${\alpha}$-Proteobacteria genera Brevundimonas, Rhizobium, and Mesorhizobium; ${\gamma}$-Proteobacteria genera Pseudomonas and Stenotrophomonas; and ${\beta}$-Proteobacteria genera Azospira, Burkholderia, Delftia, Herbaspirillum and Ralstonia. The low level of similarity of two isolates, with the type strains Paenibacillus xinjiangensis and Mesorhizobium albiziae, suggests the possibility of raising species novum. The bacterial strains of different phylogenetic groups exhibited distinct carbon-source utilization patterns and fatty acid methyl ester profiles. The strains differed in their nitrogenase activities with relatively high activity seen in the Gramnegative strains exhibiting the highest similarity to Azospira oryzae, Delftia lacustris and Herbaspirillum huttiense.

• The Plant Pathology Journal
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• v.22 no.1
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• pp.75-89
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• 2006

The actinomycete strain JK-1 that showed strong inhibitory activity against some plant pathogenic fungi and oomycetes was isolated from Jung-bal Mountain in Ko-yang, Korea. The strain JK-1 produced spores singly borne on sporophores and the spores were spherical and 0.9-1.2 11m in diameter. The cell wall of the strain JK-1 contained meso-diaminopimelic acid. The actinomycete strain JK-1 was identified as the genus Micromonospora based on the morphological, physiological, biochemical and chemotaxonomic characteristics. From the 168 rDNA analysis, the strain JK-1 was assigned to M aurantiaca. The antibiotic MA-1 was purified from the culture broth of M aurantiaca JK-1 using various purification procedures, such as Diaion HP20 chromatography, C18 flash column chromatography, silica gel flash column chromatography and Sephadex LH-20 column chromatography. $^{1}H-$, $^{13}C-NMR$ and EI mass spectral analysis of the antibiotic MA-1 revealed that the antibiotic MA-1 is identical to phenylacetic acid. Phenylacetic acid showed in vitro inhibitory effects against fungal and oomycete pathogens Alternaria mali, Botrytis cinerea, Magnaporthe grisea, Phytophthora capsici and yeast Saccharomyces cerevisiae at < 100 $\mug$ $ml^{-1}$. In addition, phenylacetic, acid completely inhibited the growth of Sclerotinia sclerotiorum, Bacillus subtilis, Candida albicans, Xanthomonas campestris pv. vesicatoria at < $\mug$ $ml^{-1}$. Phenylacetic acid strongly inhibited conidial germination and hyphal growth of M grisea and C. orbiculare. Phenylacetic acid showed significantly high levels of inhibitory' effect against rice blast and cucumber anthracnose diseases at 250 $\mug$ $ml^{-1}$. The control efficacies of phenylacetic acid against the two diseases were similar to those of commercial compounds tricyclazole, iprobenfos and chlorothalonil .n the greenhouse.

• Journal of Dairy Science and Biotechnology
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• v.24 no.1
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• pp.19-28
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• 2006

This study was conducted to isolate antilisterial strains of the Bifidobacterium isolates from the infant feces. The bifidobacteria were isolated anaerobically on BL agar and screened for their inhibitory activity on the MRS-cysteine medium against three foodborne pathogens: Listeria monocytogenes, Bacillus cereus, and Staphylococcus aureus. Among the 52 bifidobacterial isolates, 5 strains(A24, Bl, B6, B10, and Bl2) were finally selected based on their stronger antilisterial activity against Listeria monocytogenes than other isolates tested. Morphologically, all the isolates were typically shown Y-and V-shaped under electron microscopic examination. Each isolate was primarily subjected to identification by a polymerase chain reaction(PCR) using a genus-specific primer designed for targeting the 16S rRNA gene sequence, and confirmed the primary identification data using an API-kit(Biomeriuex, France), commercially available product for identification based on biochemical and physiological traits. Of the isolates with antilisterial activity, strain A24 was finally confirmed as the Bifidobacterium longum A24.

• Journal of Microbiology and Biotechnology
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• v.23 no.11
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• pp.1617-1626
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• 2013

The Bacterial community structure and its complexity of the enrichment culture during the isolation and screening of imidacloprid-degrading strain were studied using denaturating gradient gel electrophoresis analysis. The dominant bacteria in the original tea rhizosphere soil were uncultured bacteria, Rhizobium sp., Sinorhizobium, Ochrobactrum sp., Alcaligenes, Bacillus sp., Bacterium, Klebsiella sp., and Ensifer adhaerens. The bacterial community structure was altered extensively and its complexity reduced during the enrichment process, and four culturable bacteria, Ochrobactrum sp., Rhizobium sp., Geobacillus stearothermophilus, and Alcaligenes faecalis, remained in the final enrichment. Only one indigenous strain, BCL-1, with imidacloprid-degrading potential, was isolated from the sixth enrichment culture. This isolate was a gram-negative rod-shaped bacterium and identified as the genus Ochrobactrum based on its morphological, physiological, and biochemical properties and its 16S rRNA gene sequence. The degradation test showed that approximately 67.67% of the imidacloprid (50 mg/l) was degraded within 48 h by strain BCL-1. The optimum conditions for degradation were a pH of 8 and $30^{\circ}C$. The simulation of imidacloprid bioremediation by strain BCL-1 in soil demonstrated that the best performance in situ (tea soil) resulted in the degradation of 92.44% of the imidacloprid (100 mg/g) within 20 days, which was better than those observed in the ex situ simulations that were 64.66% (cabbage soil), 41.15% (potato soil), and 54.15% (tomato soil).

• Journal of Microbiology and Biotechnology
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• v.27 no.8
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• pp.1409-1418
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• 2017

Two typical microbial communities from Chinese rice wine fermentation collected in Yichang city and Suzhou city in China were investigated. Both communities could ferment glutinous rice to rice wine in 2 days. The sugar and ethanol contents were 198.67 and 14.47 mg/g, respectively, for rice wine from Yichang city, and 292.50 and 12.31 mg/g, respectively, for rice wine from Suzhou city. Acetic acid and lactic acid were the most abundant organic acids. Abundant fungi and bacteria were detected in both communities by high-throughput sequencing. Saccharomycopsis fibuligera and Rhizopus oryzae were the dominant fungi in rice wine from Suzhou city, compared with R. oryzae, Wickerhamomyces anomalus, Saccharomyces cerevisiae, Mucor indicus, and Rhizopus microsporus in rice wine from Yichang city. Bacterial diversity was greater than fungal diversity in both communities. Citrobacter was the most abundant genus. Furthermore, Exiguobacterium, Aeromonas, Acinetobacter, Pseudomonas, Enterobacter, Bacillus, and Lactococcus were highly abundant in both communities.

• Korean Journal of Microbiology
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• v.48 no.4
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• pp.246-253
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• 2012

The purpose of this study was to investigate the molecular diversity of rhizobacteria associated with ginseng of varying age levels and their plant benefiting attributes. A total of 143 different isolates belonging to 15 different bacterial genera were recovered. Although variation was found in the rhizobacterial community due to age of the plant, majority of bacteria belong to Firmicutes (58%). In which, Bacillus was found to be the predominant genus irrespective of age of the ginseng. To assess the plant benefiting attributes, 30 representative isolates were selected. The results indicated that some of the isolates could exhibit multiple plant growth promoting traits like secretion of cell wall degrading enzymes, production of indole-3-acetic acid, synthesis of siderophores, solubilization of phosphates and soil pathogens inhibition. It can be suggested that strains of B. subtilis, B. amyloliquefaciens, B. velezensis, and B. licheniformis were positive for all the above traits, which have potential to be used as plant growth promoting inoculants to improve ginseng crop in the future.