• Journal of Species Research
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• v.9 no.4
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• pp.339-345
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• 2020

The Earth contains billions of microbial species, although the vast majority cannot be cultured in laboratories and are thus considered unidentified and uncharacterized. Extremophiles are microorganisms that thrive in extreme conditions, including temperature, salinity, and pH. Extremophilic microorganisms have provided important insights for biological, metabolic, and evolutionary studies. Between 2017 and 2019, as part of a comprehensive investigation to identify bacterial species in Korea, eight bacterial strains were isolated from marine and non-marine environments in Jeju Island. These strains were cultured under extreme salinity or pH conditions. Phylogenetic analysis using 16S ribosomal RNA(rRNA) gene sequencing indicated that all eight strains belonged to the phyla Gammaproteobacteria, Bacilli, and Alphaproteobacteria. Based on their high 16S rRNA gene sequence similarities(>98.7%) and the formation of strong monophyletic clades with their closest related species, all isolated strains were considered as an unrecorded strain, previously unidentified species. Gram stain reaction, culture conditions, colony and cell morphology, biochemical characteristics, isolation source, and National Institute of Biological Resources(NIBR) IDs are described in this article. The characterization of these unrecorded strains provides information on microorganisms living in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.579-584
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• 2013

The study was conducted to investigate changes in the characteristics of inorganic components during fermenting process of organic liquid fertilizers according to the type and ratio of microorganism and the amount of molasses when producing organic liquid fertilizers using sesame oil cake and rice bran. To select appropriate microorganisms, liquid fertilizers were produced through a 90-day fermentation process by adding mag-ggeo-li, yogurt, dried yeast, and leaf mold. The pH in liquid fertilizer was decreased, and then increased in all microorganism samples except the mag-ggeo-li sample. The EC was rapidly increased in all samples until the $10^{th}$ days after production, and showed no changes after the $60^{th}$ days in dried yeast and after the $30^{th}$ days in the other samples. The concentration of $NH_4$-N was generally increased with time. The concentration of $P_2O_5$ was rapidly increased until the $10^{th}$ days after production and was maintained at about 1% regardless of the type of microorganism. In terms of the characteristics of liquid fertilizers according to the ratio of selected dried yeast, the pH was decreased until the $30^{th}$ days after producing the liquid fertilizers, and then was increased regardless of the ratio of dried yeast. The EC was increased with time and showed no differences depending on the amount of dried yeast. The concentration of $NH_4$-N was increased with time and in proportion to the amount of dried yeast. In terms of the characteristics of liquid fertilizers according to the ratio of molasses, the pH was decreased with increasing the molasses. The EC and concentration of $P_2O_5$ were no differences according to the amount of molasses. When 3% molasses was added, the content of $NH_4$-N was 2.6 mg $L^{-1}$ at the beginning and was at 3,025 mg $L^{-1}$ on the $90^{th}$ days.

• The Korean Journal of Ecology
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• v.24 no.1
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• pp.1-7
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• 2001

This study was carried out to examine the recovery of forest ecosystem by changes of soil chemical properties and soil microorganism at the burned areas of coniferous (Mt. Chocdae) and broad leaved forest (Samsinbong in Mt. Chiri). In the soil chemical properties of the burned area of Samsinbong, pH was 5.8, and contents of organic matter, total nitrogen, available P₂O/sub 5/, exchangeable K/sup ＋/, exchangeable Ca/sup ＋＋/ and exchangeable Mg/sup ＋＋/ were 7.42%, 0.73%, 28.5 ㎎/㎏, 1.3 me/100g, 13.3 me/100g and 2.2 me/100g, respectively. But they showed a tendency to decrease with time. In the soil chemical properties of the burned area of Mt. Chocdae, pH was 5.3, and contents of organic matter, total nitrogen, available P2O5, exchangeable K/sup ＋/, exchangeabe Ca/sup ＋＋/ and Exchangeable Mg/sup ＋＋/ were 6.42%, 0.25%, 24.4 ㎎/㎏, 0.7 me/100g, 3.7 me/100g and 2.1 me/100g, respectively, and they also showed a tendency to decrease with time. In contrast, they were not changed with time at the unburned areas. At the burned area of Samsinbong, soil microorganism showed to order of fungi (69×10⁴ CFU), actinomycetes (523×10⁴ CFU) and aerobic bacteria (291×10⁴ CFU), and at the unburned area, showed to order of actinomycetes (745×10⁴ CFU), fungi (594×10⁴ CFUU), and aerobic bacteria (160×10/sup 4/ CFU). At the burned area of Mt. Chocdae, soil microorganism showed to order of fungi (676×10⁴ CFU), actinomycetes (434×10⁴ CFU) and aerobic bacteria (350×10⁴ CFU), and at the unburned area, showed to order of fungi (461 ×10⁴ CFU), aerobic bacteria (328×10⁴ CFU) and actinomycetes (319×10⁴ CFU). Soil microorganisms of the aerobic bacteria, actinomycetes and fungi appeared at the burned areas were much more abundant than unburned areas. The aerobic bacteria appeared at the coniferous forest were also much more than the broad-leaved forest. The actinomycetes and fungi appeared at the broad-leaved forest were much more abundant than the coniferous forest.

• The Plant Pathology Journal
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• v.37 no.6
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• pp.596-606
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• 2021

Soil-borne diseases are the major problems in mono cropping. A mixture (designated LTM-m) composed of agricultural wastes and a beneficial microorganism Streptomyces saraceticus SS31 was used as soil amendments to evaluate its efficacy for managing Rhizoctonia solani and root knot nematode (Meloidogyne incognita). In vitro antagonistic assays revealed that SS31 spore suspensions and culture broths effectively suppressed the growth of R. solani, reduced nematode egg hatching, and increased juvenile mortality. Assays using two Petri dishes revealed that LTM-m produced volatile compounds to inhibit the growth of R. solani and cause mortality to the root knot nematode eggs and juveniles. Pot and greenhouse tests showed that application of 0.08% LTM-m could achieve a great reduction of both diseases and significantly increase plant fresh weight. Greenhouse trials revealed that application of LTM-m could change soil properties, including soil pH value, electric conductivity, and soil organic matter. Our results indicate that application of LTM-m bio-organic amendments could effectively manage soil-borne pathogens.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.162-166
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• 2004

This study investigated tile effect of ozonation on indigenous microorganisms distributed in different size fractions of soil aggregates. Soil was ozonated from 0 to 300 minutes. The treated soils were fractionated into 3 groups (small, <53 $\mu$m; medium, 53-500 $\mu$m; and large, 2000-500 $\mu$m) and total heterotrophic bacteria in the soils were enumerated. Cell number decreased rapidly within 120 minute ozonation and showed slow decrease upon longer ozonation. Abundance of total heterotrophic bacteria in each fraction was in the following order regardless of ozonation time: small>medium>large fractions. Difference in microbial abundance among the fractions was smaller as ozonation time increased.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.297-300
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• 2004

The various microbial tests were performed to determine bioremediation agent capacity for eight strains isolated from the oil contaminated regions. Two tests for isolated strains were conducted such as cell hydrophobicity and emulsifying activity. The biodegradation of SHM (saturated hydrocarbon mixture) and AHM (aromatic hydrocarbon mixture) with the strains also was carried out. The strains having higher cell hydrophobicity and emulsifying activity degraded petroleum oil effectively. The degradation capacity for SHM was represented more than 90% in YS-7 and WLH-1 of isolated strains, and KH3-2 were capable of degrading AHM. Especially, WLH-1 as yeast was shown more than two or three times in the degradation capacity of automobile engine lubricants and the biomonitoring results of contaminated soil for residual oil degrading test showed that the hydrocarbon biodegradation was increased in the second treatment by this strain.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.91-94
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• 2003

A field pilot-scale demonstration of an enhanced SVE using hot air injection and extraction was conducted to remove diesel range compounds from subsurface soils at a site in J-city, Korea. The objective of demonstration was to evaluate field ISR by intrinsic microorganism after an application study of hot air-SVE technology and to calculate each first-order kinetic with soil temperature. TPH concentration of contaminated soil at the site was approximately 2, 000~11, 000 mg/kg (average 6, 900 mg/kg) with depths greater than 5 m bgs. The 1st-order reaction rate constants, k were 0.0438(@about5$0^{\circ}C$), 0.0564(@4$0^{\circ}C$), and 0.0685(@33$^{\circ}C$) d-1 respectively.

• Journal of Microbiology and Biotechnology
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• v.22 no.4
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• pp.563-566
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• 2012

To investigate the possibility of horizontal gene transfer between agricultural microorganisms and soil microorganisms in the environment, Bacillus subtilis KB producing iturin and the PGPR recombinant strain Pseudomonas fluorescens MX1 were used as model microorganisms. The soil samples of cucumber or tomato plants cultivated in pots and the greenhouse for a six month period were investigated by PCR, real-time PCR, Southern hybridization, and terminal restriction fragment length polymorphism (T-RFLP) fingerprinting. Our data from Southern blotting and T-RFLP patterns suggest that the model bacteria do not give significant impacts on the other bacteria in the pots and greenhouse during cultivation.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1996.11a
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• pp.114-117
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• 1996

Biodegradation potential of crude oil has been studied in liquid and soil slurry culture. Studies were performed to optimize the factors affecting metabolic activity. Arabian Light(sulfur content 1%) was used as a representative crude oil and Nocardia sp. was selected as an oil degrading microorganism based on its ability to degrade and emulsify Effects of various nutritional and environmental conditions as well as emulsification and surface tension were observed. Tentative optimization of environmental and nutritional condition were as follow; pH 8, sodium nitrate as inorganic nitrogen source, yeast extract 0.05%, phosphate concentration 0.25% and glucose addition of 1.0% (w/v basis), extent of degradation to 78 %.

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.673-679
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• 2004

A microbial cryoprotectant formulation using a W/O/W multiple emulsion system was developed. The psychrotolerant microorganism, B4, isolated from soil in South Korea, was observed by the drop freezing method, in which the microorganism sample inhibited ice nucleation activity. The antifreeze activity was eliminated when the microorganism sample was treated with protease, indicating that the antifreeze activity was due to the presence of antifreeze protein. The result of the l6S rDNA sequencing indicated the B4 strain was most closely related to a species of the genus Bacillus. Culture broth of B4 strain (Bacillus sp.) and rapeseed oil containing 1 % polyglycerine polyricinolate (PGPR) were used as core and wall material, respectively. The most stable W/O emulsion was prepared at a core/oil ratio of 1:2. The highest W/O/W emulsion stability was achieved when the primary emulsion to external aqueous phase containing 0.5% caster oil polyoxyethylene ether $(COG25^{TM})$ ratio was 1:1. Microcrystalline cellulose showed better W/O/W emulsion stability than other polymer types. The viability of cells in a W/O/W emulsion was higher than free cells during storage at $37^\circ{C}$. An acidic pH and UV exposure decreased the viability of free cells, but cells in W/O/W emulsion were more stable under these conditions.