• Mycobiology
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• v.45 no.4
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• pp.385-391
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• 2017

The ability of Bacillus subtilis, strain ALICA to produce three mycolytic enzymes (chitinase, ${\beta}$-1,3-glucanase, and protease), was carried out by the chemical standard methods. Bacillus subtilis ALICA was screened based on their antifungal activity in dual plate assay and cell-free culture filtrate (25%) against five different phytopathogenic fungi Alternaria alternata, Macrophomina sp., Colletotrichum gloeosporioides, Botrytis cinerea, and Sclerotium rolfesii. The B. subtilis ALICA detected positive for chitinase, ${\beta}$-1,3-glucanase and protease enzymes. Fungal growth inhibition by both strain ALICA and its cell-free culture filtrate ranged from 51.36% to 86.3% and 38.43% to 68.6%, respectively. Moreover, hyphal morphological changes like damage, broken, swelling, distortions abnormal morphology were observed. Genes expression of protease, ${\beta}$-1,3-glucanase, and lipopeptides (subtilosin and subtilisin) were confirmed their presence in the supernatant of strain ALICA. Our findings indicated that strain ALICA provided a broad spectrum of antifungal activities against various phytopathogenic fungi and may be a potential effective alternative to chemical fungicides.

• The Korean Journal of Mycology
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• v.51 no.4
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• pp.265-276
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• 2023

This study aimed to isolate and characterize fungi from freshwater environments in South Korea and evaluate their extracellular enzyme activities. Fungal strains were collected from various freshwater sources and identified using phylogenetic analysis. The isolated fungi included known aquatic hyphomycetes and previously unreported species. Extracellular enzyme, including those of protease, amylase, lipase, cellulase, laccase, and chitinase, activities were evaluated. Among the isolated strains, several showed high enzyme activity, suggesting their potential role in organic matter decomposition in freshwater ecosystems. This research expands our knowledge of the diversity and enzyme activities of the fungi in freshwater environments, contributing to our understanding of their ecological roles.

• The Korean Journal of Malacology
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• v.27 no.1
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• pp.9-14
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• 2011

This study was examined digestive enzyme activity in the crystalline style of the three species of bivalves. Bivalves used in this study were Tegillarca granosa (n=61), Mytilus galloprovincialis (n=30) and Saxidomus purpuratus (n=30) and collected from southern coast of Korea on May 2010. Digestive enzymes activities in the crystalline style were assayed in spectrophotometer. Amylase and cellulase occupied approximately 90% of digestive enzyme in crystalline style of T. granosa, M. galloprovincialis, and S. purpuratus. And protease activity in crystalline style of T. granosa, M. galloprovincialis and S. purpuratus showed the lowest values to 0.02, 0 and 0.08%, respectively. Digestive enzyme activity in crystalline style of three species was measured in the order of cellulase > amylase > chitinase > laminarinase.

• KSBB Journal
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• v.23 no.3
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• pp.219-225
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• 2008

For the production of an antifungal compound, one strain (I-8) was selected from approximately 400 strains isolated from various soil samples. The optimum carbon source, nitrogen source and pH culture conditions for the production of the antifungal compound were investigated. ISP No. 2 medium (yeast extract 0.4%, malt extract 1% and dextrose 0.4%, at pH 8) was determined to be the optimum medium. Strain I-8 showed broad antifungal activity against the plant pathogenic fungi tested, including Sclerotinia sclerotiorum KACC 41065, as well as cellulase and chitinase activities in an agar plate assay. The extraction of antifungal compounds was performed using ethyl ether and ethyl acetate. In a culture broth of strain I-8, the ethyl acetate extract exhibited effective growth inhibition against 14 of the 20 phytopathogenic fungi tested. By mixing the ethyl acetate extract from I-8 with the ethyl ether extract from the fungus 13-16, which shows specific antifungal activity against Colletotrichum orbiculare KACC 40808, the antifungal activity of I-8 against phytopathogenic fungi was confirmed to be slightly increased. Strain I-8 showed strong growth inhibition against 16 phytopathogenic strains in agar plate tests.

• Journal of Life Science
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• v.22 no.6
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• pp.837-843
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• 2012

This study was carried out to investigate the morphological and physiological characteristics of six new cultivars of Hypsizygus marmoreus (Hm) and measure endo-, exo-cellular enzyme-specific activity. The domestic wild stain (Hm3-10) and commercial strain in Japan (Hm1-1) were mated by crossing monokaryon mycelia. We gained 58 strains from one of 400 crosses through the $1^{st}$ cultivation experiment, and selected six strains from one of 58 strains through the $2^{nd}$ cultivation experiment. When six of the selected new strains were grown during several spawn culture periods (60, 70, 80, 90, and 100 days), a spawn culture period of more 80 days was considered to be excellent as being shorter than 19~20 days. Therefore, we determined the period of spawn culture as 80 days. Three strains such as Hm15-3, Hm15-4, and Hm17-5 showed an excellent result. When endo-cellular enzyme activity measured eight strains, we obtained a result of that specific activity of ${\alpha}$-amylase at the highest as 73.9~102.2 unit/mg protein, and chitinase is lower than ${\alpha}$-amylase at 8.1~13.1 unit/mg protein. When exo-cellular enzyme activity measured eight strains, we determined the result of that specific activity of ${\alpha}$-amylase is the highest at 5,292~1,184 unit/mg protein, and CMCase and xylanase were 1,140~245 unit/mg protein, 94~575 unit/mg protein, compared to each other. However, the enzyme activity of ${\beta}$-glucosidase and chitinase is low.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.66-73
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• 2012

Plant growth promoting traits like production of indoleacetic acid (IAA), ammonia, hydrogen cyanide (HCN), siderophore, and like the enzyme activities of catalase, ACC deaminase, cellulase, chitinase and protease were assayed in vitro for twenty one phosphorus solubilizing bacteria isolated from soil isolates. Except SPP-5 and SPP-15 strains, all the other isolated strains produced IAA in various amounts of 10 to $23{\mu}g\;ml^{-1}$. All strains showed positive response for ammonia production and ACC deaminase activity implying that they are capable of growing in a N-free basal medium. Catalase activity was found to be superior in SPP-2, SPP-7, SPP-12 and SPP-17 compared to the other strains tested. HCN production was detected by 15 strains and among them SPP-9, SPP-15, SAph-11, and SAph-24 were found to be strong HCN producers. Except the isolates SPP-10, SPP-12, SPP-13 and SPP-14, all the other isolates produced more than 80% siderophore units. None of the strains showed cellulose and chitinase activity. SAph-8, SAPh-11, SAPh-24 and SPP-15 strains showed 35.84, 50.33, 56.64 and 34.78 U/ml protease activities, respectively. SPP-1, SPP-2, SPP-3, SPP-11, SPP-17, SPP-18, SAph-11 and SAph-24 strains showed positive response for all the tested plant growth promotion traits except cell wall degrading enzyme activities. According to the results, all the tested phosphorus solubilizing isolates could exhibit more than three or four plant growth promoting traits, which may promote plant growth directly or indirectly or synergistically. Therefore, these phosphorus solubilizing strains could be employed as bio-inoculants for agriculture soils.

• The Korean Journal of Mycology
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• v.41 no.1
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• pp.42-46
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• 2013

Burkholderia pyrrocinia CAB08106-4 was parceled out from the Chungnam Agricultural Research and Extension Center, Korea to evaluate the antagonistic activity against garlic white rot caused by Sclerotium cepivorum. The optimum cultural conditions including temperature, pH, enzyme activity, carbon and nitrogen sources were determined. The optimum culture conditions of B. pyrrocinia CAB08106-4 were $286^{\circ}C$, 150 rpm and pH 7. Chitinase only showed activity among several tested enzymes. The highest cell growth was obtained with 1% glucose and 0.1% $(NH_4)_2SO_4$, respectively.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.117-126
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• 2010

A chitinase (CHT) and a protease (PRO) were purified from the culture supernatant of Serratia sp. TKU017, with shrimp shell as the sole carbon/nitrogen source. The molecular masses of CHT and PRO determined by SDS-PAGE were approximately 65 kDa and 53 kDa, respectively. CHT was inhibited by $Mn^{2+}$ and $Cu^{2+}$, and PRO was inhibited by most tested divalent metals and EDTA. The optimum pH, optimum temperature, pH stability, and thermal stability of CHT and PRO were pH 5, $50^{\circ}C$, pH 5-7, and <$50^{\circ}C$, and pH 9, $40^{\circ}C$, pH 5-11, and <$40^{\circ}C$, respectively. PRO retained 95% of its protease activity in the presence of 0.5 mM SDS. The result demonstrates that PRO is an SDS-resistant protease and probably has a rigid structure. The $4^{th}$-day supernatant showed the strongest antioxidant activity (70%, DPPH scavenging ability) and the highest total phenolic content ($196{\pm}6.2\;{\mu}g$ of gallic acid equiv./ml). Significant associations between the antioxidant potency and the total phenolic content, as well as between the antioxidant potency and free amino groups, were found for the supernatant. With this method, we have shown that shrimp shell wastes can be utilized and it is effective in the production of enzymes and antioxidants, facilitating its potential use in industrial applications and functional foods.

• Korean Journal of Food Science and Technology
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• v.25 no.4
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• pp.366-372
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• 1993

This study mainly designed to high quality of mirin production by using protopast fusion. In order to enhance the acid carboxypeptidase (ACPase) activity by the method of protoplast fusion. In order to enhance the acid carboxypeptidase (ACPase) activity by the method of protopalst fusion, the mutants, Aspergillus oryzae 9-12 and Aspergillus shirosamii IFO 6082-60 were selected by mutation among various mutants. Protoplast of Aspergillus oryzae 9-12 and Aspergillus shirousamii IFO 6082-60 were formed effectively by incubation of the mixtures of chitinase (10mg/ml), cellulase (10mg/ml) and zymolase 20T (5mg/ml). For protopalst fusion, the mixture of two mutant were fused to effective under the optimum conditions by solutions containing 30% PEG 6,000, 0.01M $CaCl_2\;2H_2O$, 0.6M KCl and 0.05M glycine. Fusion frequency was 0.71% and fusant, F-50 appeared ACPase activity of 20,800 unit/g which has 1.5 times higher than that of each mutants.

• Korean Journal of Microbiology
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• v.36 no.2
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• pp.97-102
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• 2000

In order to use Metarhizizmn~ anisopliae as a biological pesticide, effect of envrionmental factors on nlycelial growth, spore formation, and extracellular enzyme activity in culture broth of M. anisopliae DGUM 35001 was determined. Optimal temperature was 26^{\circ}C.$ and optimal pH ranged from 5 to 9. Among the complex media tested, MCM and SDPY media were the most favorable for mycelial growth. When Czapek-Dox agar was used as a mnimal medium, glucose and sucrose among the saccharides were very excellent source of carbohydrate. Among the biopolyners tested. chitin was the most favorable source for mycelial growth and produced high aerial inycelia. Urea and ammonium phosphate as an inorganic nitrogen source and bacto-peptone and soytone as an organic nitrogen source enhanced the mycelial growth When serine as a source of amino acid was supplemented, excellent mycelial growth was shown. Large amount of spores could be obtained from the aerial mycelia of starch medium. When the culture broth was filtrated and then the concentrate with ammonium sulfate was used as a crnde enzyme solution, high enzyme activities of amylase and protease were shown. However, lipase and chitinase activities were comparatively low.