• The Korean Journal of Mycology
• /
• v.25 no.3 s.82
• /
• pp.161-166
• /
• 1997

Occurrence of Hypoxylon truncatum, known as a symbiont of white jelly mushroom, was first noted and described in Korea. Two stromatal forms reported in North American collections of H. truncatum sensu Miller were also observed in Korean collections. Based on evidences from other studies, polymorphic patterns seen in six enzyme digestions of nuclear Internal Transcribed Spacer (ITS) regions of Korean isolates indicated that the two stromatal forms were genetically distinct. Because there was a clear association of stromatal morphology with genetic differences, the different stromatal forms might be different species. In addition, clear species concept on the species H. truncatum would provide aids in selecting proper strain for cultivation of white jelly mushrooms.

• Applied Biological Chemistry
• /
• v.47 no.2
• /
• pp.164-169
• /
• 2004

In the course of our screening for biocontrol agent (BCA) against Streptomyces scabiei and S. turgidiscabies causing potato scab using 5,000 actinomtcete isolates, 9 antagonistic strains were selected as BCA candidates through in vitro and in vivo assay. An antagonistic strain, A020645 was highly resistant to some pesticides and antibiotics such as dazomet and mancozeb and showed high control value in vivo. Two bioactive compounds (compound A, B) were purified by anion exchange chromatography, solid phase (ODS) extraction, TLC and reverse phase HPLC. Their chemical structures are now thought to be nucleoside derivative as determined by $^1H-NMR$ data analysis. Their full chemical structures would be elucidated through $^{13}C-NMR$, HMQC and HMBC analyses. Further studies will be focused on fitness in soil and formulation of the BCA candidates.

• Korean Journal of Food Science and Technology
• /
• v.34 no.6
• /
• pp.1085-1090
• /
• 2002

Leuconostoc mesenteroides, the major bacterium in the initial phase of lactate-fermentation in kimchi, produces lactic acid, acetic acid, mannitol, and $CO_2$. It also secrets dextransucrase, which catalyzes the transfer reaction of glucose from sucrose to maltose, synthesizing mainly panose ($6^_2-{\alpha}-D-glucopyranosylmaltose)$, a probiotic oligosaccharide. To use the strain as a starer culture to produce high amount of panose during kimchi fermentation, we screened psychrotrophic strains showing fast growth rate at low temperature among the isolates of Leuconostoc sp. and selected two strains showing high dextransucrase activity. The strains were identified as Leuconostoc mesenteroides, which can be used as function added-starters for lactate-fermented foods.

• Journal of Dairy Science and Biotechnology
• /
• v.31 no.2
• /
• pp.133-141
• /
• 2013

This study was performed to identify the cheese starter potential of antifungal lactic acid bacteria isolated from Kimchi. Eight fungi were isolated from cheese or the cheese ripening room, and identified as Penicillium and Cladosporium by ITS-5.8S rDNA analysis. Twenty-two lactic acid bacteria species with antifungal activity were isolated from Kimchi, and identified as Lactobacillus and Pediococcus by 16S rRNA sequence analysis. Six lactic acid bacteria species were selected (L. sakei subsp. ALJ011, L. sakei subsp. ALI033, L. sakei subsp. ALGy039, P. pentosaceus ALJ015, P. pentosaceus ALJ024, and P. pentosaceus ALJ026) based on higher antifungal activity from the initial 22 species. Out of the six identified species, L. sakei subsp. ALI033 had the highest antifungal activity. For growth of the six lactic acid bacteria, optimal temperature and pH were $30{\sim}37^{\circ}C$ and 7.0, respectively. Proteolytic activities of the six lactic acid bacteria were almost as strong as the commercial strain Str. thermophilus Body-1. Coagulative activities of L. sakei subsp. ALI033, P. pentosaceus ALJ015, and P. pentosaceus ALJ024 were higher than those of L. sakei subsp. ALJ011, L. sakei subsp. ALGy039, and P. pentosaceus ALJ026. The acid resistance of L. sakei subsp. was higher than that of P. pentosaceus. The major organic acid component of the lactic acid bacteria culture medium was lactic acid.

• Journal of Mushroom
• /
• v.10 no.2
• /
• pp.93-99
• /
• 2012

This study was carried to identify a correct species and asses genetic diversity within the same species of Grifola spp. preserved in Division of applied Microbiology. Contaminated isolates showed different growth rates, morphology and color of hyphae. We have reconstructed the phylogenetic tree of a select group of Grifola spp. using nucleotide sequences of the internal transcribed spacer region(ITS) region. The phylogenetic tree was constructed by using the neighbor-joining method. PELF primers of 20-mer were used to assess genetic diversity of preserved isolates. Sequence analysis showed that four strains were identified completely different nomenclature. According to the analysis of ITS sequences, the genus Grifola clustered into one group, most of which correlated with species-groups identified by RAPD method. Eight isolates included strain GM01 showed high similarity with Grifola frondosa. All isolates were collected in the Japan(GM01, GM02, GM03) was identified as Grifola frondosa and isolates of the China(GM05, GM06, GM08) was identified as Bjerkandera fumosa, Grifola frondosa and Dichomitus squalens, respectively. RAPD analysis of genetic polymorphisms of genus Grifola showed a very different band patterns on the isolat. As the result of RAPD and ITS region sequences analysis for preserved isolates, it seems likely that 4 isolates of Grifola spp. may be need to reclassify or eliminate from preserved catalogue.

• Microbiology and Biotechnology Letters
• /
• v.26 no.6
• /
• pp.476-482
• /
• 1998

Growth sensitivity of bifidobacteria on oxygen hindered their industrial applications so that it was necessary to select oxygen-tolerant strains. Studies on their responses to oxygen might facilitate the effective utilization of bifidobacteria in industry. Oxygen-tolerant strain of Bifidobacterium longum JI-1 was able to remove 3% dissolved oxygen within 10 min whilst oxygen-sensitive strain of B. adolescentis, slime non-former, was not. The ability to remove environmental oxygen seemed to be related to the oxygen-tolerance of bifidobacteria. Mutant B. longum ADJ-1 was induced from the B. longum JI-1 under microaerobic atmosphere. There were no differences in sugar utilization pattern, NADH oxidative enzymes and cellular fatty acid compositions between them. The maximal cell density of the mutant was a little bit reduced to 81% of that of the mother strain. However, the mutant formed thick slime layer around its cell. The layer visualized with confocal scanning laser microscopy from the mutant was 6 ${\mu}{\textrm}{m}$ in diameter but that from the mother strain was only 3 ${\mu}{\textrm}{m}$. Therefore, the improved tolerances of the mutant might come from the slime layer, indicating the increase of the layer might be one of oxygen tolerance mechanisms for bifidobacteria.

• The Korean Journal of Pesticide Science
• /
• v.19 no.4
• /
• pp.402-410
• /
• 2015

The purpose of this study was to estimate the chitinolytic and antifungal activity of Actinomycetes sp.isolated from waste mushroom media. In five kinds of waste mushroom media, Sinyeong mushroom and Yangsongi were the order of the population density of actinomycetes. Totally 91 chitinolytic isolates of Actinomycetes sp. were obtained from waste mushroom media. The isolates were categorized into 3 groups based on chitinolytic activity and antagonisms against Phytophthora capsici, Rhizoctonia solani, Sclerotinia sclerotiorum, Collectotrichum gloeosporioides, and Cladosporium cucumerinum in vitro. CA-23 was selected as a representative isolate of a group showing strong chitinolytic and antagonistic activities to all of the plant pathogens, while AA-65 was selected as a representative isolate showing no chitinolytic activities but strong antagonistic activities to the pathogens. CA-23 and AA-65 were highly effective on control of Phytophthora blight of hot-pepper, powdery mildew and scab of cucumber in a greenhouse tests. Among the isolates tested, CA-23 showed highest control efficacy, while AA-65 not only effectively controlled the diseases but also consistently increased plant growth and yield. Although the isolates are similarly affected on suppression of plant pathogens, the isolates could be differ from each other in modes of action. Further studies on mechanisms and practical applications are being progressed.

• Journal of Dairy Science and Biotechnology
• /
• v.38 no.2
• /
• pp.89-98
• /
• 2020

The purpose of this study was to investigate the probiotic properties of lactic acid bacteria (LAB) isolated from a Korean traditional food kimchi. Gram staining was performed by Macrogen (Macrogen, Inc.) for identification of the LAB. Five strains of LAB were identified, including DKGF9 (Lactobacillus plantarum), DKGF1 (L. paracasei ), DKGF8 (L. casei ), DK207 (L. casei ), and DK211 (L. casei ). The biological activities of the isolated strains were assessed. The results showed that heat resistance of the strains was similar to or higher than the commercial strain L. acidophilus LA-5. Indirect testing of the ability of the strains to attach to the mucin layer revealed that DKGF9, DKGF1, and DKGF8 have high binding affinities for the mucous layer. All strains showed antimicrobial activity similar to or higher than the commercial strain LA-5. In proteolysis experiments, the diameters of proteolysis zones of the five strains increased in the period of 24-72 h, with DKGF1 exhibiting the largest zone diameter. Three strains were selected based on their antioxidant activities. Among the five isolated strains, L. paracasei DKGF1 showed potential probiotic activity, and thus, it may be useful for the development of health-promoting products.

• The Korean Journal of Mycology
• /
• v.37 no.1
• /
• pp.65-72
• /
• 2009

For the breeding purpose, in this study we attempted to select a new Lentinula edodes strain by comparing mycelial growth rate, fruit-body quality and mushroom productivity per substrate weight of hybrid strains with parent strains. Nineteen hybrid strains were made by cross of di-karyotic and mono-karyotic to develop strains suitable for sawdust cultivation of L. edodes. Among the nineteen strains, ten were selected by comparing mycelial growth rate on PDA media and wood rot on sawdust-based substrates. The most mushroom harvesting was achieved by 100 days incubation from KFRI 960, KFRI 961, KFRI 962, KFRI 963, KFRI 964, KFRI 971, KFRI 973 and 125 days from KFRI 968, 970. Experiment of incubation periods with the ten strains showed that there were productivity differences between 100 and 150 days incubations. Through comparison of hybrid strains' mushroom productivity it was found that there was no difference in mushroom productivity through crossing high temperature types with high temperature types, crossing low temperature types with high temperature types and crossing unknown temperature types with high temperature types, but there was difference through crossing middle temperature types with high temperature types. Hybrid strains showed better productivity compared with parent strains. Fruiting temperature type analysis of hybrid strains confirmed that strains of high temperature types have a dominant character.

• Microbiology and Biotechnology Letters
• /
• v.38 no.4
• /
• pp.373-378
• /
• 2010

Studies on standardization and quality upgrade of nuruk which is a basic component in brewing are required to increase the quality level of Korean traditional rice wines and to develop the technology for practical use of it. It is important to isolate best strains, to improve the properties and effectively preserve them for brewing industry. In this study, 16 commercial nuruk samples were obtained from the commercial markets located in Chungcheong areas in Korea. 174 fungal strains were isolated from the samples on DG18 medium using a dilution plating method and then screened for enzyme activity and acid production. The active strains were identified based on the morphological characteristics and ITS sequence analysis. Out of 174 strains, 12 strains showed high amylase activity. Especially, Rhizopus sp. CN084, CN174, Aspergillus sp. CN161 and Mycocladus sp. CN042 showed high saccharogenic power and dextrinogenic enzyme activity on cooked wheat bran medium. On the other hand, Aspergillus sp. CN010, CN161, Rhizopus sp. CN105, CN168 and Rhizomucor sp. CN088 produced high acid production on the same medium. Our results showed that the active strains may be used as microbial sources for nuruk starter with good quality in brewing.