• Korean Journal of Ecology and Environment
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• v.35 no.4 s.100
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• pp.326-330
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• 2002

A wetland soil was sterilised by two methods and changes in microbial enzyme activities were assessed. The short-term effects were determined by toluene addition, while the longer-term effects of elimination was monitored by ${\gamma}$-radiation. The changes in ${\beta}$- glucosidase, ${\beta}$-xylosidase, cellobiohydrolase, phosphatase, arylsulphatase, and N-acetylglucosaminidase activities were determined by using methylumbelliferyl model substrates and comparing with the activities of control samples. Toluene addition induced different responses of enzymes. For example, phosphatase activity increased by the treatment while ${\beta}$-glucosidase and arylsulphatase activities decreased. In contrast, ${\gamma}$-radiation decreased all enzyme activities compared to control by 40-80%. The overall results of the toluene and ${\gamma}$-radiation experiments indicate that the large amounts of enzymes are stabilised outside of living cells, at least in the short term, but that the persistence of enzymes is maintained by de-novo synthesis of microbes.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.346-356
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• 2011

BACKGROUND: Chemical fungicides not only may pollute the ecosystem but also can be environmentally hazardous, as the chemicals accumulate in soil. Biological control is a frequently-used environment-friendly alternative to chemical pesticides in phytopathogen management. However, the use of microbial products as fungicides has limitations. This study isolated and characterized a three-antifungal-enzyme (chitinase, cellulase, and ${\beta}$-1,3-glucanase)-producing bacterium, and examined the conditions required to optimize the production of the antifungal enzymes. METHOD AND RESULTS: The antifungal enzymes chitinase, cellulase, and ${\beta}$-1,3-glucanase were produced by bacteria isolated from an sawmill in Korea. Based on the 16S ribosomal DNA sequence analysis, the bacterial strain AM50 was identical to Streptomyces sp. And their antifungal activity was optimized when Streptomyces sp. AM50 was grown aerobically in a medium composed of 0.4% chitin, 0.4% starch, 0.2% ammonium sulfate, 0.11% $Na_2HPO_4$, 0.07% $KH_2PO_4$, 0.0001% $MgSO_4$, and 0.0001% $MnSO_4$ at $30^{\circ}C$. A culture broth of Streptomyces sp. AM50 showed antifungal activity towards the hyphae of plant pathogenic fungi, including hyphae swelling and lysis in P. capsici, factors that may contribute to its suppression of plant pathogenic fungi. CONCLUSION(S): This study demonstrated the multiantifungal enzyme production by Streptomyces sp. AM50 for the biological control of major plant pathogens. Further studies will investigate the synergistic effect, to the growth regulations by biogenic amines and antifungal enzyme gene promoter.

• Journal of Korea Soil Environment Society
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• v.4 no.1
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• pp.13-23
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• 1999

In this research, 3-hydroxypyridine(2-HP) metabolic ability of starving Arthrobacter crystallopoietes cell and the effect of humic acid on the metabolism of this starving cell were evaluated. 2-HP metabolic ability of exponential phase cell (acclimated cell) was much higher than that of lag phase cell (unacclimated cell) during starvation period. After 3 days of starvation, 2-HP half-life of the acclimated cell was 14 hours and that of the unacclimated cell was 46.5 hours. Humic acid enhanced the stability of 2-HP monooxygenase of starving co]1 and, after 2 days of starvation, the residual activity rate of this enzyme of the microbial cell starved in humic acid solution was 12% while the rate for control condition was 1.5%. After 14 days of starvation, 2-HP half-life for control condition was 43 hours and that for humic acid condition was 1.25 hour.

• The Korean Journal of Mycology
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• v.13 no.4
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• pp.203-212
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• 1985

Of 450 strains isolated from the soil microbes collected in various locations in Korea, a strain had a strong inhibitory activity against bacterial ${\alpha}-amylase$ and was named strain DMC-72 of the genus Streptomyces. The amylase inhibitory metabolite produced by this strain was purified by means of acetone precipitation, adsorption on Amberlite IRC-50 and SP-Sephadex C-25. The inhibitor was found to be a derivative of oligosaccharides by spectral and chemical data. The inhibitor was stable at the pH range of $1{\sim}13$ and at $100^{\circ}C$ for half an hour, also inhibited other amylases such as salivary ${\alpha}-amylase$, pancreatic ${\alpha}-amylase$, fungal ${\alpha}-amylase$ and glucoamylase. However, it showed no inhibitory activity against ${\alpha}-glucosidase$, ${\beta}-glucosidase$, dextranase, and ${\beta}-amylase$. The kinetic studies of the inhibitor showed that its inhibitory effects on starch hydrolysis by ${\alpha}-amylase$ were noncompetitive.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.2
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• pp.127-134
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• 2017

Bottom ash (BA) has different macro- and micronutrients such as B, Mo, Fe, Ca, and Mg, providing useful resources for plant growth and soil quality. The objective of this study was to evaluate the applicability of artificial top-soil treated with BA in park area as a vegetation base material, especially for turfgrass growth. Collected BA was mixed with peat moss and clay at the ratio of 70:10:20 (w/w). In order to evaluate the park quality and turfgrass growth in park area, the artificial soil was applied with BA along with the control or without BA. Result showed that exchangeable K and P were increased by $11.4mg\;kg^{-1}$ and $163mg\;kg^{-1}$, respectively, compared to the control soil when the artificial soil was treated with BA. Microbial population and enzyme activity (Acid-phosphatase, APA) in artificial soil having BA also increased as 2 times and 10%, respectively, compared to the control soil. Comparing turfgrass growth and yield between general soil and artificial soil, about 2 times higher plant yield (fresh weight) was observed as artificial soil was applied comparing to general soil. Furthermore, nutrient concentration in turfgrass was averaged as 0.440% for $P_2O_5$, 0.456% for CaO, 1.198% for $K_2O$ and 0.188% for MgO that all values are higher than general soil (0.323% for $P_2O_5$, 0.416% for CaO, 0.610% for $K_2O$ and 0.173% for MgO). Application of BA can be useful for vegetation base material in park site.

• Microbiology and Biotechnology Letters
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• v.4 no.4
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• pp.138-144
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• 1976

five strains of Streptomyces spp. with high Productivity of glucose isomerase (15-30 units/ml) were obtained among 280 microbial strains isolated from 150 soil samples. These strains produced glucose isomerase with xylose as an inducer. These 5 strains were also identified to be different strains of Streptomyces spp.：streptomyces sp. K-14, K-53, K-71, K-77 and K-733. It was found that Streptomyces sp. K-14 produced the highest enzyme activity. The spore chains of these strains were rectiflexible and spore surface was smooth except Steptomyces sp. K-77 and K-733, with spiny surface.

• Microbiology and Biotechnology Letters
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• v.28 no.4
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• pp.219-222
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• 2000

To produce and utilize microbial cyclomaltodextrinase being industrially useful, we isolated an alkalophilic Bacillus strain from soil which was capable of degrading cyclodextrins. The newly isolated strain was aerobic, gram-positive, spore-forming, motile, rod shape(0.2~0.4$\times$1.4~4.4 $\mu\textrm{m}$), and 35.8 mol% of DNA base composition. Based on its morphological, phisiological, and biochemical properties, it was identified as alkalophilic Bacillus sp. KJ-133 and cultivated well in the ranges of $30~40^{\circ}C$ and pH 8.0~9.0 . The cyclomaltodextrinase of the strain showed maximal production after 48h of cultivation at $37^{\circ}C$, and the activity was inhibited by Ag2+, Hg2+, Cu2+, and p-chloromercuribenzoate.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.403-412
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• 2021

This study aimed to identify plant growth-promoting activity, phytopathogenic fungi growth inhibitory activity, mineral solubilization ability, and extracellular enzyme activity of the genus Bacillus in soil and the rhizosphere. With regards to antifungal activity against phytopathogenic fungi, DDP257 showed antifungal activity against all 10 pathogenic fungi tested. ANG20 showed the highest ability to produce indole-3-acetic acid, a plant growth-promoting factor (70.97 ㎍/ml). In addition, 10 species were identified to have 1-aminocyclopropane-1-carboxylate deaminase production ability, and most isolates showed nitrogen fixation and siderophore production abilities. Thereafter, the isolated strains' ability to solubilize minerals such as phosphate, calcite, and zinc was identified. With extracellular enzyme activity, the activity appeared in most enzymes. In particular, all the strains showed similar abilities for alkaline phosphatase, esterase (C4), acid phosphatase, and naphtol-AS-BI-phosphohydrolase production. This result was observed because the genus Bacillus secreted various organic substances, antibiotics, and extracellular enzymes. Therefore, through the results of this study, we suggest the possibility of using strains contributing to the improvement of the soil environment as microbial agents.

• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.576-586
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• 2021

The purpose of this study was to evaluate the antifungal activity, plant-growth-promoting activity, and mineral solubilization ability of 10 species of phytopathogenic fungi to select a Bacillus sp. from rhizosphere soils and roots that can be used as a microbial agent. The antifungal activity for phytopathogenic fungi varied based on the Bacillus sp. Among the selected strains, DDP4, DDP16, DDP148, SN56, and SN95 exhibited antifungal activity for nine or more species of phytopathogenic fungi. Regarding nitrogen-fixation ability, all Bacillus sp. showed similar levels of activity, and siderophore production ability was relatively high in ANG42 and DDP427. The indole-3-acetic acid production abilities were in the range of 1.83-67.91 ㎍/ml, with variations in activity based on the Bacillus sp. One strain with a high activity was selected from each species, and their mineral solubilization abilities were examined. Most Bacillus sp. could solubilize phosphoric acid and calcium carbonate, and DDP148 and SN56 could solubilize silicon and zinc, respectively. These results suggested that Bacillus sp. can be considered potential multi-purpose microbial agents for plant growth promotion and disease prevention.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.199-207
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• 2024

We conducted to investigate both plant growth-promoting and plant disease-controlling activities of bacterial strains isolated from soil. Among the 48 isolated strains, SH-23, SH-26, SH-29, and SH-33 were identified as excellent strains for the production of β-glucosidase, cellulase, amylase, and protease. These 4 strains exhibited antifungal activity against plant pathogenic fungi (Botrytis cinerea, Rhizoctonia solani, Fusarium oxysporum, Colletotrichum acutatum). Strain SH-26, which exhibited excellent organic matter decomposition and antifungal activity against plant pathogenic fungi, was selected as the final superior strain. Upon determining the 16S rRNA gene sequence of the selected SH-26 strain, it exhibited 100% similarity with Pseudomonas knackmussii HG322950 B13^T, Pseudomonas citronellolis BCZY01000096 NBRC 103043^T, and Pseudomonas delhiensis jgi.1118306 RLD-1^T. Furthermore, it was confirmed that the Pseudomonas sp. SH-26 exhibited siderophore production, nitrogen fixation ability, and the production of Indole-3-acetic acid.