• Mycobiology
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• v.46 no.4
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• pp.396-406
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• 2018

A newly isolated white rot fungal strain KU-RNW027 was identified as Trametes polyzona, based on an analysis of its morphological characteristics and phylogenetic data. Aeration and fungal morphology were important factors which drove strain KU-RNW027 to secrete two different ligninolytic enzymes as manganese peroxidase (MnP) and laccase. Highest activities of MnP and laccase were obtained in a continuous shaking culture at 8 and 47 times higher, respectively, than under static conditions. Strain KU-RNW027 existed as pellets and free form mycelial clumps in submerged cultivation with the pellet form producing more enzymes. Fungal biomass increased with increasing amounts of pellet inoculum while pellet diameter decreased. Strain KU-RNW027 formed terminal chlamydospore-like structures in cultures inoculated with 0.05 g/L as optimal pellet inoculum which resulted in highest enzyme production. Enzyme production efficiency of T. polyzona KU-RNW027 depended on fungal pellet morphology as size, porosity, and formation of chlamydospore-like structures.

• 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.

• Mycobiology
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• v.47 no.1
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• pp.50-58
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• 2019

Agarum clathratum, a brown macroalgae species, has recently become a serious environmental problem on the coasts of Korea. In an effort to solve this problem, fungal diversity associated with decaying A. clathratum was investigated and related ${\beta}$-glucosidase and endoglucanase activities were described. A total of 233 fungal strains were isolated from A. clathratum at 15 sites and identified 89 species based on morphology and a multigene analysis using the internal transcribed spacer region (ITS) and protein-coding genes including actin (act), ${\beta}$-tubulin (benA), calmodulin (CaM), and translation elongation factor (tef1). Acremonium, Corollospora, and Penicillium were the dominant genera, and Acremonium fuci and Corollospora gracilis were the dominant species. Fifty-one species exhibited cellulase activity, with A. fuci, Alfaria terrestris, Hypoxylon perforatum, P. madriti, and Pleosporales sp. Five showing the highest enzyme activities. Further enzyme quantification confirmed that these species had higher cellulase activity than P. crysogenum, a fungal species described in previous studies. This study lays the groundwork for bioremediation using fungi to remove decaying seaweed from populated areas and provides important background for potential industrial applications of environmentally friendly processes.

• Mycobiology
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• v.49 no.6
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• pp.559-581
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• 2021

The coastal marine ecosystems of Vietnam are one of the global biodiversity hotspots, but the biodiversity of marine fungi is not well known. To fill this major gap of knowledge, we assessed the genetic diversity (ITS sequence) of 75 fungal strains isolated from 11 surface coastal marine and deeper waters in Nha Trang Bay and Van Phong Bay using a culture-dependent approach and 5 OTUs (Operational Taxonomic Units) of fungi in three representative sampling sites using next-generation sequencing. The results from both approaches shared similar fungal taxonomy to the most abundant phylum (Ascomycota), genera (Candida and Aspergillus) and species (Candida blankii) but were different at less common taxa. Culturable fungal strains in this study belong to 3 phyla, 5 subdivisions, 7 classes, 12 orders, 17 families, 22 genera and at least 40 species, of which 29 species have been identified and several species are likely novel. Among identified species, 12 and 28 are new records in global and Vietnamese marine areas, respectively. The analysis of enzyme activity and the checklist of trophic mode and guild assignment provided valuable additional biological information and suggested the ecological function of planktonic fungi in the marine food web. This is the largest dataset of marine fungal biodiversity on morphology, phylogeny and enzyme activity in the tropical coastal ecosystems of Vietnam and Southeast Asia. Biogeographic aspects, ecological factors and human impact may structure mycoplankton communities in such aquatic habitats.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.47-47
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• 2014

Dokdo island is located in the northeastern part of Ulleungdo, known as volcanic island. In total, 53 fungal isolates were isolated from Dokdo island soil sample, using dilution plate technique. The isolates were identified on the basis of morphological characteristics and rDNA ITS sequence analysis. Out of them, 41 isolates were identified at the level of species. The dominant fungal species and genera included Fusarium spp., Mucor sp., Clonostachys spp., and Trichoderma sp. The % sequence identity (the number of matches/the complete alignment length) values via NCBI BLAST searching of EML-IF9, EML-MF30-1 and EML-DDSF4 represented 97.19% (485/499) with Clonostachys cf. rosea (GenBank accession no. KC313107), 98.33% (472/480) with Metarhizium guizhouense (GenBank accession no. HM055445), and 100% (350/350) with Mortierella oligospora (GenBank accession no. JX976032), respectively. Three species of C. rosea, M. guizhouense and M. oligospora represented new records of fungi from Dokdo island, Korea. The antimicrobial activities of the fungal strains varied with tested. Two isolates (EML-MFS30-1 and EML-IF9) showed antifungal activity against several fungi including Fusarium oxysporum and Rhizotonia solani. Clonostachys rosea (EML-IF9) showed strong hydrolytic enzyme activity. Our results showed that the antagonistic fungi including Clonostachys rosea will be used as potential biocontrol agents for control of fungal diseases.

• The Plant Pathology Journal
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• v.15 no.3
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• pp.144-151
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• 1999

Chitinase activities from Shumard oak tissues were determined to study changes in chitinase activities related to water stress. The enzyme extracted in sodium acetate buffer (0.1M, pH 4.5) was assayed by a colorimetric method. In addition, the fungal hyphae of Hypoxylon atropunctatum in xylem tissues of oak were observed through scanning electron microscopy. The enzyme in oak tissues was mainly endochitinase, and optimum pH for enzyme activity was 5. Specific chitinase activities from both of stems held under high relative humidity (ranges of 0.63-1.11 pKatal/$\mu\textrm{g}$ of protein) and stems held under low relative humidity (ranges of 0.41-0.99 pKatal/$\mu\textrm{g}$ of protein) were significantly increased following fungal inoculation with H. atropunctatum. However, there was no significant difference in chitinase activities between tissues held under high and low humidities, which might be due to fungal chitinase. Scanning electron microscopy showed holes in fungal hyphae in the xylem tissues of stems held under high humidity but not in the stems held under ow humidity, suggesting that hyphae might be hydrolyzed by plant hydolases such as chitinase.

• Microbiology and Biotechnology Letters
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• v.27 no.6
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• pp.466-470
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• 1999

Protease production and its characteristics were investigated with Mucor racemosus f. racemosus PDA 103 which was isolated from Korean traditional meju. Optimum culture conditions of the strain for the production of the protease in basic medium[bean(Baektae):H2O=1:1(w/v)] were as follows: pH 6, 3$0^{\circ}C$ and 72hrs. Optimum pH and temperature for the enzyme activity of the protease produced by Mucor racemosus f. racemosus were pH 5 and 5$0^{\circ}C$, respectively. The enzyme was relatively stable a pH2.0~5.0 and at temperature below 4$0^{\circ}C$. Phenylmethane-sulfonyl fluoride and Ag+ inhibited the enzyme activity. This indicates that the enzyme is serine protease. Km value was 0.9$\times$10-4M and Vmax value was 5.93$\mu\textrm{g}$/min. This enzyme hydrolyzed casein more rapidly than bovine albumin.

• Microbiology and Biotechnology Letters
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• v.27 no.6
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• pp.446-451
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• 1999

The protease produced by Mucor racemosus f. racemosus PDA 103 from meju was purified by precipitating with 80% saturated ammonium sulfate, CM Sephadex C-50 ion-exchange chromatography, and secondary Sephadex G-100 gel filtration chromatography. The specific activity of the purified enzyme was 60.1unit/mg protein and the purification fold of the enzyme was 83.5. The molecular weight of the enzyme was estimated 33,746Da and the enzyme was elucidated as monomer by LC-MS and SDS-PAGE. The number of amino acids was evaluated about 330 residues.

• Journal of Microbiology and Biotechnology
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• v.20 no.4
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• pp.718-726
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• 2010

A selected fungal strain, for production of the raw-starchdigesting enzyme by solid-state fermentation, was improved by two repeated sequential exposures to ${\gamma}$-irradiation of $Co^{60}$, ultraviolet, and four repeated treatments with Nmethyl-N'-nitrosoguanidine. The mutant strain Aspergillus sp. XN15 was chosen after a rigorous screening process, with its production of the raw-starch-digesting enzyme being twice that of usual wild varieties cultured under preoptimized conditions and in an unsupplemented medium. After 17 successive subculturings, the enzyme production of the mutant was stable. Optimal conditions for the production of the enzyme by solid-state fermentation, using wheat bran as the substrate, were accomplished for the mutant Aspergillus sp. XN15. With the optimal fermentation conditions, and a solid medium supplemented with nitrogen sources of 1% urea and 1% $NH_4NO_3$, 2.5 mM $CoSO_4$, 0.05% (v/w) Tween 80, and 1% glucose, the mutant Aspergillus sp. XN15 produced the raw-starch-digesting enzyme in quantities 19.4 times greater than a typical wild variety. Finally, XN15, through simultaneous saccharification and fermentation of a raw rice corn starch slurry, produced a high level of ethanol with $Y_{p/s}$ of 0.47 g/g.

• YAKHAK HOEJI
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• v.43 no.4
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• pp.502-508
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• 1999

Chitin is an important structural component of fungal cell wall and is synthesized by chitin synthase I, II, and III. The chitin synthase II is an essential enzyme for the formation of primary septum in Saccharomyces cerevisiae. Therefore, specific inhibitors of this enzyme might block the formation of fungal cell wall and could be used as effective antifungal agents. To search chitin synthase IIinhibitors from natural products, 67 plants were extracted with methanol and examined for the inhibitory activities against chitin synthase II of S. cerevisiae by our cell free assay system. As a result, the extracts from 16 plants showed more than 70% inhibition at the concentration of $280{\;}\mu\textrm{g}/ml$. Of note, Laurus nobilis (81.4%), Lonicera maackii (81.5%), Berchemia berchemiaefolia (82.9%), Koelreuteria paniculata (87.9%), Chamaecyparis pisifera (86%) and Taxus cuspidata (83.9%) inhibited strogly the chitin synthase IIactivity.