• The Korean Journal of Ecology
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• v.26 no.6
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• pp.307-312
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• 2003

To study the diversity of heterotrophic bacteria isolated from intestine of starfish, Asterias amurensis, we collected starfishes from the coastal area near Jangheung-Gun, Jeollanam-Do, Korea during July, 2000. Population density and bacterial diversity in the intestine of starfish were measured. The results were as follows; The population densities of heterotrophic bacteria in the intestine of starfish were 8.65${\pm}$0.65${\times}10^3\;dfu\;g^{-1}$. Gram positive bacteria occupied 59% among 29 isolates. The community structure of dominant heterotrophic bacteria in the intestine of starfish consisted of Bacillaceae in the low G+C gram positive bacteria subphylum, Microbacteriaceae in the high G+C gram positive bacteria subphylum, and Alteromonadaceae in ${\gamma}$-Proteobacteria subphylum. Among eight strains of Bacillus spp., three strains showed more than 97% identity, but five strains showed about 90% identity with type strain on the basis of partial 16S rDNA sequence.

• Microbiology and Biotechnology Letters
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• v.9 no.3
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• pp.145-152
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• 1981

Microorganisms from the waste water of starch industry, were isolated and a strain, Y-124, possessing a powerful enzymic activity was selected and identified as a member of the genus Bacillus. The ideal cultural condition for the formation of $\alpha$-amylase form Bacillus Y-124 and its preservation was investigated in connection with the biotechnological and industrial approach to the bulk enzyme production. High yield of $\alpha$-amylase was observed in medium containing casein as well as calcium pantothenate in this work. Calcium ions were found to have an effect in forming this particular enzyme. Ammonium phosphate dibasic was an important inorganic nitrogen source for the formation of $\alpha$-amylase. And preservation of this enzyme was greatly affected by calcium or sodium salts. The addition of calcium carbonate or sodium sulfate presented the most effective result for the prevention of its denaturation to various factors. The above data was obtained with crude enzyme preparation.

• Applied Biological Chemistry
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• v.40 no.3
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• pp.173-177
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• 1997

Bacillus licheniformis 9945a releases a natural ${\gamma}-poly(glutamic\;acid)({\gamma}-PGA)$ into fermentation broth and shows a mucoid phenotype on the solid agar medium. Transformation of mucoid cells of Bacillus species has not been simple and straightforward. The transpositional activity of Tn10 in B. licheniformis also has not been own either. Thus, a spontaneous non-mucoid derivative of the B. licheniformis was obtained first. Shuttle vector pHV1248 containing mini-Tn10 was introduced into the non-mucoid derivative by the method of protoplast transformation. The resulting transformant was reverted to the wild mucoid phenotype, and then mutated randomly with the mini-transposon by heat induction. Auxotrophs requiring arginine, lysine, or tryptophan were isolated by replica plating method. Southern blotting and DNA-DNA hybridzation analysis showed that these auxotrophs were generated by mini-Tn10 insertion into the chromosomal DNA. This method of transformation and mutation using pHV1248 would be useful for the generation of diverse mutants of B. licheniformis 9945a.(Received January 24,1997; accepted March 10, 1997)

• Microbiology and Biotechnology Letters
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• v.16 no.5
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• pp.343-347
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• 1988

The promoters of alkali-tolerant Bacillus sp. had been cloned in the promoter probe vector pPL703 and recombinant plasmid p-12 had been constructed. As a result of subcloning, two different promoters were found to exist in the cloned 2.9 kb promoter fragment and two recombinant plasmids p-l2B1 and p-l2B2, each harboring different promoter, were constructed. The promoter activity, which was expressed in the CAT specific activity, of p-l2B1 was 7 times higher than that of p-l2B2. The promoter activity as a function of growth revealed that both promoters of p-l2B1 and p-l2B2 were expressed after the late logarithmic growth phase and repressed in the presence of 1.0％ (w/v) glucose.

• The Korean Journal of Mycology
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• v.46 no.1
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• pp.83-90
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• 2018

Melon powdery mildew, caused by Podosphaera fusca, is one of the serious diseases of melon plant in Korea. In this study, we evaluated the effect of selected antagonistic bacteria on the inhibition of mycelial growth of various plant pathogens, and control of melon powdery mildew. Based on the 16S rDNA and gyrA gene sequences, the selected antagonistic bacteria, M09, M70, and M99-1, were identified as Bacillus velezensis. These bacteria not only inhibited the mycelial growth of 47~69% in various plant pathogens, but also significantly reduced the incidence of powdery mildew. The three strains selected in this study could be used as potential biological control agents for various plant diseases as well as melon powdery mildew.

• Korean Journal of Food Science and Technology
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• v.23 no.3
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• pp.349-354
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• 1991

An alkaline amylase-producing Bacillus sp. GM8901 was isolated and some properties of crude enzyme extract were examined. The microbiological and biochemical characteristics of GM8901 were very similar to those of B. licheniformis. The optimal temperature and pH for the cell growth and amylase production were $50^{\circ}C$ and pH 10.5. The crude amylase extract showed that the optimal temperature and pH were $50{\sim}60^{\circ}C\;and\;pH\;10{\sim}12$, respectively, and that the activity of amylase was stable up to $50^{\circ}C$ and in the range of $pH\;3{\sim}12$.

• Journal of agriculture & life science
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• v.43 no.5
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• pp.57-62
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• 2009

This study was conducted to analyze to the applicability of refined saps of Acer mono, A. mono for. rubripes, A. okamotoanum through sap refining system. 1 species of Bacillus genus, 3-4 species of yeast and 2 species of fungi were detected in the origin sap of three Acer spp. The pH in the origin sap were 6.5, and decreased in refining sap as 6.3-6.4. Sucrose in sugar components was detected in the origin and refining sap of Acer spp., but glucose and fructose were not detected. Compared the origin and refining sap, mineral components decreased slightly in refining sap. These results indicate that refining sap of Acer spp. are drinkable with long-term storage.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.197-203
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• 1998

Although biological metabolism in soil is very important for evaluating the soil properties, most of researches have concerned mainly about physical and chemical sides. In this study, biological characteristics were examined to demonstrate the biota in the plastic film house soils. Contents of organic matter and phosphate in soil were increased with cultivation period. ECs of soil cultivated spinach and melon were $3.59dS\;m^{-1}$ and $3.46dS\;m^{-1}$ respectively: these values were higher than that of rose and flower, which were $1.23dS\;m^{-1}$ and $1.32dS\;m^{-1}$ respectively. The population of fluorescent Pseudomonas strains of the soil cultivated flowers: $113.8{\times}10^4{\sim}129.7{\times}10^4cfu\;g^{-1}$ was higher than that of leafy vegetables: $40.7{\times}10^4{\sim}97.9{\times}10^4cfu\;g^{-1}$ and fruiting vegetables: $25.0{\times}10^4{\sim}91.7{\times}10^4cfu\;g^{-1}$. However the number of Fusarium strains of the soil cultivated with flowers: $3.8{\times}10^2{\sim}4.0{\times}10^2cfu\;g^{-1}$ was lower than that of leafy vegetables: $4.3{\times}10^2{\sim}16.3{\times}10^2cfu\;g^{-1}$ and fruiting vegetables: $7.6{\times}10^2{\sim}30.0{\times}10^2cfu\;g^{-1}$. In relation to the cultivation period, the habitation density of aerobic bacteria, mesophilic Bacillus, thermophilic Bacillus, and fluorescent Pseudomonas strains was the highest in the soil cultivated over 11 years, but diversity index showed negative correlation with cultivation period. Microbial biomass C in these soils had positive correlation with each number of microorganisms including aerobic bacteria, actinomycetes, and strains of mesophilic Bacillus as well as the total number of these microorganisms.

• Microbiology and Biotechnology Letters
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• v.48 no.1
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• pp.57-63
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• 2020

Over the past 20 years, global warming has transformed the marine ecosystem of the Jeju Island into a subtropical zone making it conducive to the production of tropical fishes. Recently, the balloon fish (Diodon holoanthus) has been found off the coast of the Jeju Island. In this study, we analyzed the diversity of its intestinal microorganisms as a representative for the surrounding environment. In addition, the isolates were evaluated for their antibacterial activity. A total of 161 strains of various species were identified and isolated using 16S ribosomal RNA gene sequence analysis. They were separated into three groups, of which Phylum Proteobacteria was found to be the most dominant with 91% sequence similarity. This includes the class γ-proteobacteria that is made up of twelve genera and twenty-four hundred species. The second group comprised strains of the genus Vibrio, made up of 35% Photobacteria, 32% Shewanella, and 6% Psychrobacter. It was also determined that 4% of the isolates were Acinetobacter, 3% were Enterovibrio, while Moraxella_g2 accounted for 1% of the total isolates. Class α-proteobactera includes five genera and five species; Brevundimonas, Allorhizobium, Pseudoceanicola and Erythrobcter, each accounting for 1% of the total isolates. The Firmicute strains belonged to six genera and ten species. 5% of the strains were Terribacillus, while Paenibacillus, Salinicoccus, Staphylococcus and Streptococcus accounted for 1% each of the total isolates. Actinobacteria accounted for the final phylum with strains belonging to three genera and ten species with Janibacter, Micrococcus and Isoptericola each accounting for 1% of the total isolates.

• Microbiology and Biotechnology Letters
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• v.26 no.6
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• pp.551-557
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• 1998

Whole soybean cereal was fermented with four Aspergillus strains in pilot meju fermentation system. The pH range of the product was 7.40~7.98, the contents of reducing sugar and amino-nitrogen were 0.04~2.78%, 178~309 mg%, respectively and that of free fatty acid ranged 2.67~5.05%. The components of the amino acid, organic acid, free sugars and fatty acid showed distinctive patterns among four groups of fermented soybean cereals. Amylase activity and carbohydrate degradation rate of A. usami was higher than other strains. But protease and protein degradation rate, lipase and lipid degradation rate were similar in four strains. The odor concentrates of soybean cereals fermented with Aspergillus strains were different from Bacillus strains. Especially, pyrazine components, the main and common flavor chemicals in Bacillus strains, were not determined in this study and Aspergillus specific components were 9-methyl-acridine, dl-limonene and 2,3-butanediol. Soybean paste, made from A. oryzae fermented soybean cereal, showed excellent sensory evaluation.