• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.5
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• pp.456-460
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• 2009

Biofilm is a structured community of microorganism encapsulated within a self-developed polymeric matrix and adherent to a living or a solid surface. In this study, we investigated the effects of various substrates on the formation of biofilm in Vibrio parahaemolyticus. We found that biofilm formation profoundly increased in a substrate, that consisted of calcium chloride, calcium nitrate, and calcium sulfate in 1% peptone water. On the other hand, a dramatic reduction in biofilm formation was observed in a substrate, that consisted of glucose and ferric chloride in LB broth. These results suggest that V. parahaemolyticus prefer to form a biofilm on the surface of a crustacean or a clam, where calcium ion is rich, and also where seawater temperature is relatively lower. In contrast, high levels of glucose in a crustacean or a clam body resulting from increased seawater temperature, can make V. parahaemolyticus detach from it and lead to free floating.

• Microbiology and Biotechnology Letters
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• v.24 no.6
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• pp.693-698
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• 1996

Optimal cultural conditions were investigated for the maximal productivity of nucleoside oxidase and peroxidase from Flavobacterium meningosepticum. Sucrose and Polypepton were the best as a carbon source and a nitrogen source. Fe$^{2+}$, Fe$^{3+}$ and Cu$^{2+}$ increased the activities of the two enzymes and were essential in medium containing peptone as a nitrogen source. Nucleoside derivatives such as 2'-deoxyguanosine, 2'-deoxyadenosine, N$^{6}$ -methyladenosine and 1-methyladenosine were effective for the production of the two enzymes. Especially, the addition of N$^{6}$ -methyladenosine and 1-methyladenosine decreased cell growth, but increased the two enzyme activities. High level of oxygen also was an essential factor for formation and/or induction of these enzymes. From the summary of this study about optimal medium and environmental conditions, nucleoside oxidase was biosynthesized in proportion to peroxidase. These results suggested that the role of peroxidase should be degradation of H$_{2}$O$_{2}$ generated by nucleoside oxidase in the cell of Flavobacterium meningosepticum.

• Microbiology and Biotechnology Letters
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• v.24 no.6
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• pp.699-704
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• 1996

About 600 microorganisms isolated from soil, marsh, compost, etc. were examined for their flocculating ability in the kaolin suspension and swine wastewater. Among them, K-199 was the best producer of flocculant and was identified to be a species belong to the genus Corynebacterium. The maximum production of the flocculant from Corynebacterium sp. K-199 was observed in culture medium containing 2% glycerol, 0.4% peptone, 0.3% K$_{2}$HPO$_{4}$, 0.1% CaCO$_{3}$, 0.05% NaCl, 0.1% yeast extract, 0.1% MgSO$_{4}$,7H$_{2}$O and initial pH 7.5 when cultured with rotary shaker controlled at 25$\circ$C and 150 rpm. Under the optimal culture condition with jar fermentor, the maximum production was reached to flocculating activity of 780 units/ml after 4 days. From the results of the activity be fully maintained by periodate oxidization, it suggests that the activity is due to the protein.

• Microbiology and Biotechnology Letters
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• v.27 no.5
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• pp.404-409
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• 1999

The most favorable nitrogen source for the production of protease by Aspergillus oryzae PF was 2% soybean flour among sodium nitrate, ammonium sulfate, defatted soybean, skim milk, casein, peptone, and yeast extract. The production of protease from A. oryzae PF was higher at the concentration of 2% lactose than at variable concentration of glucose, sucrose, soluble starch, corn starch, potato starch, wheat starch, rice starch, cellulose, and gum arabic. Protease production was affected by the concentration of KH2PO4, Triton X-100, CaCo3, and MgSO4, and it was the highest at the highest at the concentration of 3% KH2PO4, 0.01% Triton X-100, 0.3% CaCO3, and 0.06% MGSO4.

• Microbiology and Biotechnology Letters
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• v.27 no.5
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• pp.391-398
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• 1999

A methylotrophic actinomycetes strain MO-16, which produce the antimicrobial compound, was isolated from soil and supposed as Amycolatopsis sp. based on taxonomic studies. The cell-free extract of methanol-grown strain MO-16 showed dehydrogenase activity for methanol and formaldehyde when various electron acceptors were added for oxidation. On the other hand, methanol did not affect the production of antimicrobial compounds, and organic nitrogen sources such as corn steep liquor and peptone were better than inorganic nitrogen sources. These compounds showed broad antimicrobial spectrum to the tested strains such as bacteria and yeast. The antimicrobial comounds were very stable under heat(121$^{\circ}C$), acid(pH2.0), alkali(pH11.0) treatments. These compounds were isolated by ethylacetate extract, silica gel column chromatography and reverse phase HPLC. Two compounds(peak 1 and 2) were detected as antimicrobial compounds through the HPLC analysis. The peak 2 was purified as a single compound and revealed a 98% purity.

• Mycobiology
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• v.33 no.3
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• pp.142-146
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• 2005

To produce a novel antihypertensive angiotensin I-converting enzyme (ACE) inhibitor from yeast, a yeast isolate, designated G-14 showing the highest ACE inhibitory activity was obtained and identified as Malassezia pachydermatis based on morphological, biochemical and cultural characteristics. The maximal extracellular ACE inhibitor production was obtained from M. pachydermatis G-14 when the strain was cultured in YEPD medium containing 0.5% yeast extract, 3.0% peptone and 2.0% glucose at $30^{\circ}C$ for 24 h and the final ACE inhibitory activity was 48.9% under the above condition.

• Mycobiology
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• v.42 no.2
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• pp.198-202
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• 2014

Two new yeast records, Cryptococcus adeliensis YJ19-2 and Cryptococcus uzbekistanensis YJ10-4 were screened from 60 yeasts strains that were isolated and identified from wild flowers in Yokjido, Gyeongsangnam-do, Korea. The morphological and cultural characteristics of the newly recorded yeasts and the physiological functionalities of the supernatants and cell-free extracts obtained from their cultures were investigated. The two newly recorded yeasts did not form ascospores and pseudomycelia. They also grew well in yeast extract-peptone-dextrose broth. C. uzbekistanensis YJ10-4 grew in a vitamin-free medium and was also tolerant to sugar and salt. Antihypertensive angiotensin I-converting enzyme inhibitory activity of the supernatant from C. adeliensis YJ19-2 was high (71.8%) and its cell-free extract also showed very high (81.2%) antidiabetic $\acute{a}$-glucosidase inhibitory activity.

• Journal of Life Science
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• v.6 no.4
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• pp.270-277
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• 1996

Streptococcus sp J-C1 producing bacteriocin was isolated from Kimchi. The optimum conditions for bacteriocin production by Streptococcus sp. J-C1 were evaluated. For the maximum yield of bacteriocin production by Streptococcus sp. J-C1, the cell should be harvested at the late stationary phase and the temperature, pH and NaCl concentration should be 25$\circ$C, pH 8 and without the addition of NaCl, respectively. Sucrose should be used as a carbon source and organic nitrogen such as peptone should be used as a nitorgen source for the best yield. The production of bacteriocin is related to the cell growth of Streptococcus sp. J-C1. The bacteriocin from Streptococcus sp. J-C1 was active for gram positive microorganisms such as Lactobacillus sp., Leuconoctoc sp., Lactococcus sp., Streptococcus mutans, Staphylococcus aureus amd Bacillus subtilis and also active for gram negetive bacteria such as Acetobacter aceti. Antibacterial activity of the bacteriocin was completely disappeared by protease treatment.

• Mycobiology
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• v.33 no.2
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• pp.118-120
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• 2005

Most commonly occurring predacious fungus Arthrobotrys oligospora showed great variation in size and shape of conidia on some media. The formation of larger conidia was recorded on beef extract and nutrient agar media. The length of conidia in Richard's YPSS, Sabouraud's, PDA and com meal agar media was of medium size while smaller conidia were produced on Czapek's, Jensen's, Martin's medium. Maximum width of conidia was recorded on YPSS medium followed by Sabouraud's medium. The average size of spores on nematode infested com meal agar medium was slightly increased than those on com meal agar medium.

• Mycobiology
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• v.29 no.4
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• pp.210-217
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• 2001

Seventy-three species and five varieties belonging to 36 genera were collected from leaf surfaces of banana plants on glucose and cellulose-Czapek's agar at $28^{\circ}C$. The results obtained from leaf surfaces(phyllosphere and phylloplane) were basically similar on the two types of media and the most common fungi were Alternaria, Aspergillus, Chaetomium, Cladosporium, Cochliobolus, Curvularia, Gibberella, Memnoniella, Mycosphaerella, Setosphaeria and Stachybotrys. The monthly counts of these fungi were irregularly fluctuated giving maxima at various months. Chaetomium globosum was in the top of fungi in producing both exo- and endo-$\beta$-l,4-glucanases among the 34 tested isolates obtained from leaves(phylloplane) on cellulose-Czapek's agar. Maximum production of these enzymes by C. globosum was 6 and 8 days after incubation at $25^{\circ}C$ with culture medium containing wheat bran as a carbon source and peptone as a nitrogen source and initially adjusted to pH 6.