• Microbiology and Biotechnology Letters
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• v.37 no.3
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• pp.189-196
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• 2009

Bacteria were isolated from roots of plants belonging to family Solanaceae and Gramineae, inhabited in Dokdo island. Fifty six endospore-forming bacteria grown on tryptic soy broth (TSB) agar medium and 23 nitrogen-fixing bacteria (NFB) grown on nitrogen free agar medium were isolated, respectively. The isolates were partially identified by analyzing the 16S rDNA and categorized into phylogenetic groups. The 16S rDNA sequences of each identified isolates were compared with sequences of each type strains to analyze phylogenetic relationship by phylogenetic tree. As a result, endospore-forming bacteria and nitrogen-fixing bacteria were classified into 4 and 6 lineage groups, respectively. Among these isolated, 18 were presumed to be novel species candidates based on the similarity (lower than 98%) analysis of the l6S rDNA sequences.

• Journal of Microbiology
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• v.45 no.2
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• pp.113-121
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• 2007

The bacterial diversity inherent to the biofilm community structure of a modified rotating biological contactor wastewater treatment process, referred to as the Rotating Activated Bacillus Contactor (RABC) process, was characterized in this study, via both culture-dependent and culture-independent methods. On the basis of culture-dependent methods, Bacillus sp. were found to exist in large numbers on the biofilm (6.5% of the heterotrophic bacteria) and the microbial composition of the biofilms was quite simple. Only three phyla were identified-namely, the Proteobacteria, the Actinobacteria (High G+C Gram-positive bacteria), and the Firmicutes (Low G+C Gram-positive bacteria). The culture-independent partial 16S rDNA sequence analysis revealed a considerably more diverse microbial composition within the biofilms. A total of eight phyla were recovered in this case, three of which were major groups: the Firmicutes (43.9%), the Proteobacteria (28.6%), and the Bacteroidetes (17.6%). The remaining five phyla were minor groups: the Planctomycetes (4.4%), the Chlorobi (2.2%), the Actinobacteria (1.1%), the Nitrospirae (1.1%), and the Verrucomicrobia (1.1%). The two most abundant genera detected were the endospore-forming bacteria (31.8%), Clostridium and Bacillus, both of which are members of the Firmicutes phylum. This finding indicates that these endospore-forming bacteria successfully colonized and dominated the RABC process biofilms. Many of the colonies or clones recovered from the biofilms evidenced significantly high homology in the 16S rDNA sequences of bacteria stored in databases associated with advanced wastewater treatment capabilities, including nitrification and denitrification, phosphorus accumulation, the removal of volatile odors, and the removal of chlorohydrocarbons or heavy metals. The microbial community structures observed in the biofilms were found to correlate nicely with the enhanced performance of advanced wastewater treatment protocols.

• Korean Journal of Microbiology
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• v.47 no.1
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• pp.56-65
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• 2011

Culture-independent microscopic observations and 16S rDNA analyses were applied to describe the bacterial community inherent to the biofilm structure of the RABC (Rotating Activated Bacillus Contactors) process for swine butchery wastewater treatment. The ratios of Gram-positive bacterial counts to total bacterial counts of the RABC process were significantly increased in the last aeration tank as well as returned sludge, while those of the existing A2O (Anaerobic-Anoxic-Oxic) process maintained constant from aeration tanks to returned sludge. Totally nine phyla were recovered by 16S rDNA analysis, two of which were major groups: the Proteobacteria (64.1%) and the Actinobacteria (18.4%). The third major group was the endospore-forming Firmicutes (5.4%). The remaining six minor groups are the Bacteroidetes (3.3%), the Chlorobi (2.2%), the Nitrospirae (1.1%), the Chlorofleix (1.1%), the Acidobacteria (1.1%), and the Fusobacteria (1.1%). The ratio of endospore-forming bacteria was 19.4%, which was composed of the members of the Firmicutes phylum (5.4%) and the Intrasporangiaceae family (14.0%) of the Actinobacteria phylum. Nitrifying and denitrifying related- and phosphorus accumulating related-sequences were composed of 6.5% and 5.4% of total community, respectively, these could mean the high capacity of the RABC process to remove odor compounds and reduce eutrophication by efficient removing inorganic nutrients.

• Microbiology and Biotechnology Letters
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• v.23 no.5
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• pp.580-587
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• 1995

In order to produce the bacteriolytic enzyme, bacterial strains capable of excreting a large amount of the enzyme were screened from the coastal sea water samples in Pusan. The bacterial strain SH-1, which showed the highest activity among 43 bacteriolytic enzyme producing bacteria, was finally selected for further studies. The strain SH-1 was an endospore-forming grampositive rod, and the position of spore was paracentral. These morphological characteristics assigned the isolated strain to the morphological group I classified by Gordon. The fatty acid composition of the bacterial stain was analyzed to be consisted of branched chains of iso-Cn and anteiso-Cn. Based on the percent content of the branched chain (93.85%), the isolates could be identified as a species of Bacillus. According to the experimental results of the API system (API 50CHB & API 20E) the strain was identified as Bacillus subtilis. Numerical texonomy, in which 82 major characters were examined using several species of Bacillus as the standard bacteria, indicated that the strain SH-1 showed 90% similarity to Bacillus subtilis. Thus, the isolated strain SH-1 could be identified as Bacillus subtilis.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2199-2210
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• 2017

Soil burial is the most widely used disposal method for infected pig carcasses, but composting has gained attention as an alternative disposal method because pig carcasses can be decomposed rapidly and safely by composting. To understand the pig carcass decomposition process in soil burial and by composting, pilot-scale test systems that simulated soil burial and composting were designed and constructed in the field. The envelope material samples were collected using special sampling devices without disturbance, and bacterial community dynamics were analyzed by high-throughput pyrosequencing for 340 days. Based on the odor gas intensity profiles, it was estimated that the active and advanced decay stages were reached earlier by composting than by soil burial. The dominant bacterial communities in the soil were aerobic and/or facultatively anaerobic gram-negative bacteria such as Pseudomonas, Gelidibacter, Mucilaginibacter, and Brevundimonas. However, the dominant bacteria in the composting system were anaerobic, thermophilic, endospore-forming, and/or halophilic gram-positive bacteria such as Pelotomaculum, Lentibacillus, Clostridium, and Caldicoprobacter. Different dominant bacteria played important roles in the decomposition of pig carcasses in the soil and compost. This study provides useful comparative date for the degradation of pig carcasses in the soil burial and composting systems.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.1
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• pp.103-108
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• 2023

In this study, basic research was conducted to secure microbial resources applicable to autonomous crack healing concrete. To this end, in this experiment, biomineral-forming microorganisms were separated from natural sources, and the ability of survival in cement and calcium carbonate precipitation were compared to secure suitable microbial resources. Bacillus-type bacteria forming endospores were isolated from the sample, and the amount of calcium carbonate produced by the six microorganisms identified by 16S rRNA sequencing was compared. Two types of microorganisms, Bacillus velezensis and Bacillus subtilis, with the highest calcium carbonate precipitation were selected, and the survival of the microorganisms was confirmed through phase contrast microscopy after being cured after being added to the mortar. In addition, it was confirmed that the autonomous crack healing capability by the crack healing material produced by microorganisms was confirmed by artificially generating cracks in the mortar.

• The Korean Journal of Ecology
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• v.21 no.5_2
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• pp.575-583
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• 1998

Physicochemical factors, microbial population size and the properties of the bacterial isolates were assessed to find out the nature of soil ecosystem of Mt. Paektu. Samples were obtained from the surface layer of soils on which specific plant community is developed. Average content of moisture, organic matter and avaiable phosphate of the soils were 21.6%, 17.3% and 2.48mg/100g, respectively. These values were similar to those of developing forest soils, but were slightly lower than those of climax ecosystem such as Piagol in Mt. Chiri. The population size of soil bacteria ranged from 2.7 to $202.5{\times}10^5$ CFU/g.dry soil, and the size is somewhat dependent on the content of moisture and oranic matter of the forest soil. A large number of bacteria was able to decompose macromolecules such as starch, elastin and gelatin. While the distribution rate of resistant bacteria to antibiotics was high, that to toxic chemicals was low. This means that the competition between microorgani는 predominate over the interference with artificial behaviour such as spread of pesticides in the surveyed region. Bacterial species composition of each soil was comparatively simple. Pseudomonas, Agrobacterium, Flavobacterium and Xanthomonas which are Gram-negative short rods were widely distributed in the forest soils. The endospore forming Bacillus species were also main constituents of the soil microflroa. any one of the strains was not identified as Azospirillum or Micrococcus which are known to be one of major constituents of the forest soil. for the correct identification of isolates chemotaxonomic studies will be proceeded, and the strains are to be stored in the Type collection Center.

• Journal of Applied Biological Chemistry
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• v.50 no.4
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• pp.202-210
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• 2007

A total of 45 bacterial strains were isolated from the traditional Korean soybean-fermented food, Chungkookjang. Among these strains, seven strains were selected and identified based on morphological, physiological, and biochemical characteristics, as well as phylogenetic analysis using 16S rDNA sequences. All strains were Gram-positive, aerobic, motile, oxidase-positive, rod-shaped, and endospore-forming bacteria, and produced extracellular enzymes such as amylase, cellulase, lipase, protease, and xylanase. The isolates were grown in the presence of 0-11% (w/v) NaCl. Growth was optimal at pH 6-9 and at temperatures of $30-45^{\circ}C$. According to VITEK automicrobic system tests and supplementary tests, the isolates were similar to several species of the genus Bacillus. The phylogenetic analysis of seven bacterial strains based on comparisons of 16S rDNA sequences, revealed that the strains were closely related to Bacillus species. The identification of strains that produced surfactin was also carried out, based on PCR screening of the sfp gene. Among the seven isolated strains, six yielded a surfactin-positive result with PCR.

• The Korean Journal of Ecology
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• v.21 no.5_3
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• pp.703-712
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• 1998

Physicochemical factors, microbial population size and the properties of the bacterial isolates were estimated to find out the nature of soil ecosystem of Mt. Nam. Samples were obtained from the surface layer of soils on which specific plant community is developed. Average content of moisture and organic matter of the soils were 21.6% and 17.3%, respectively. These values were similar to those of developing forest soils, but were slightly lower than those of climax ecosystem such as Piagol in Mt. Chiri. Chiri. Content of phosphate was higher than those of other forest soils. The population size of soil bacteria ranged from 27.4 to 195.8 ${\times}\;10^5$ CFU/g. duy soil, and the size is somewhat dependent on the moisture and oranic matter content of soils. A large number of bacteria were able to decompose macromolecules such as starch, elastin and gelatin. Bacterial species composition of each soil was comparatively simple. Pseudomonas, Agrobacterium, Flavobacterium and Xanthomonas which are Gram-negative short rods were widely distributed in the forest soils. The endospore forming Bacillus species were also the main constituents of the soil microflroa. Actinomycetes were widely distributed in the forest soils, but the distribution pattern varied in each site. Most of the actinomycetes were also able to decompose organic macromolecules. The rate of resistant actinomycete strains to antibiotics and heavy metals were lower than those from cultivated soils, but higher than those from well-preserved forest soils. Antibiosis pattern of the actinomycete isolates was similiar to the resistance pattern. This means the forest soils of Mt. nam was somewhat interferred by artificial behabiour.

• Research in Plant Disease
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• v.22 no.2
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• pp.81-93
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• 2016

Out of plant-associated bacteria, certain plant growth-promoting bacteria (PGPB) have been reported to increase plant growth and productivity and to elicit induced resistance against plant pathogens. In this study, our objective was to broaden the range of applications of leaf-colonizing PGPB for foliar parts of road tress and pepper. Total 1,056 isolates of endospore-forming bacteria from tree phylloplanes were collected and evaluated for the enzymatic activities including protease, lipase, and chitinase and antifungal capacities against two fungal pathogens, Colletotrichum graminicola and Botrytis cinerea. Fourteen isolates classified as members of the bacilli group displayed the capacity to colonize pepper leaves after spraying inoculation. Three strains, 5B6, 8D4, and 8G12, and the mixtures were employed to evaluate growth promotion, yield increase and defence responses under field condition. Additionally, foliar application of bacterial preparation was applied to the road tress in Yuseong, Daejeon, South Korea, resulted in increase of chlorophyll contents and leaf thickness, compared with non-treated control. The foliar application of microbial preparation reduced brown shot-hole disease of Prunus serrulata L. and advanced leaf abscission in Ginkgo biloba L. Collectively, our results suggest that leaf-colonizing bacteria provide potential microbial agents to increase the performance of woody plants such as tree and pepper through spray application.