• Journal of Life Science
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• v.20 no.1
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• pp.77-81
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• 2010

We separated the bacteria showing protease activity from Reticulitermes speratus which is known as the only termite species in Korea. Then, we collected the best activated strain and studied the optimal culture condition for producing the enzyme. According to the results of observing morphological and physiological characteristics, and the type of 16S rRNA of the strain, it was identified as Serratia marcescens and named S. marcescens strain TM-3215. This strain showed the best activity under conditions of 0.8% (w/v) starch, 0.4% (w/v) peptone, 0.08% (w/v) $MgSO_4{\cdot}7H_2O$, $30^{\circ}C$ and pH 8.0. After being cultivated under optimal conditions for 9 hr, the strain produced 19.8 U/ml of enzyme, an amount 1.8 times greater than the control.

• The Korean Journal of Mycology
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• v.24 no.3 s.78
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• pp.214-222
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• 1996

This study was carried out to obtain the basic data on artificial culture of Phellinus linteus. The optimum condition for the mycelial growth was $25{\sim}30^{\circ}C$ and pH $6.0{\sim}7.0$. The carbon sources such as D-glucose, D-mannose and Dextrose were favorable to mycelial growth. As nitrogen sources, peptone, cassamino acid and glutamic acid appeared to be favorable. The optimum C/N ratio was about 20:1, when 2% of glucose was provided as a carbon source. The better organic acids and vitamin among tested ones were gallic, silicic acids and biotin. The mineral nutrients of $KH_2PO_4,\;FeSO_4{\cdot}7H_2O,\; MgSO_4{\cdot}7H_2O,\;ZnSO_4{\cdot}7H_2O$ were effective and the optimum concentrations were 0.05, 0.001, 0.02 and 0.003%, respectively.

• The Korean Journal of Mycology
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• v.42 no.3
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• pp.225-230
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• 2014

Sclerotinia sclerotiorum, a plant pathogenic fungus, can cause serious yield and quality losses in the winter lettuce field. For biological control of S. sclerotiorum, soil-born microorganisms that inhibit the mycelia growth of S. sclerotiorum and Fusarium oxysporum were isolated from diseased soil. Among the isolates, bacterial isolate, GG95, which was identified as Bacillus subtilis according to the morphological, physiological characteristics and by 16S rRNA similarity, showed the highest level of inhibitory activity. The growth conditions for B. subtilis GG95 were optimized in TSB media (pH 7) by culturing at $28^{\circ}C$ for 24 hrs. Maltose or fructose and peptone were selected as the best carbon and nitrogen sources, respectively. Greenhouse experiment was performed to test effectiveness of B. subtilis GG95 in the control sclerotinia rot. Drench application ($1{\times}10^8cfu/mL$, 3 times) of the bacterial culture broth to lettuce showed an effectiveness value of 88%, suggesting that B. subtilis GG95 would be a promising biocontrol agent for control of sclerotinia rot.

• Applied Biological Chemistry
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• v.50 no.2
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• pp.87-94
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• 2007

A bacterium which has high enzymatic activities such as amylase, cellulase and protease was isolated from Korean traditional soybean food, doenjang. The isolated bacterium was identified to Bacillus subtilis HS25 by the test of morphological and biochemical properties according to Bergey's Manual of Systematic Bacteriology and API 50 CHL kit, and by the 16S rDNA sequence. The isolated B. subtilis HS25 had a potent antibacterial activity against food born causative or pathogenic bacteria. B. subtilis HS25 is endospore forming cell and contained flagella and abundant viscous material at the out layer of cell wall. It was rod type bacterium $(0.5{\sim}0.8{\times}3{\sim}5{\mu}m)$ having biochemical characteristics such as gram staining(+), catalase(+), oxidase(-) and hydrolysis of esculin(+). The optimal medium compositions for production of antibacterial substance in the B. subtilis HS25 were 1% of soluble starch, 0.5% of yeast extract, 0.5% of peptone and 0.05% of MgCl$_2{\cdot}6H_{2}O$. The optimum temperature and pH of the growth of the B. subtilis HS25 was 35$^{\circ}C$ and pH 7.5, respectively. The antibacterial activity was more high in neutral to a little alkaline pH (6.5-10.5) than in acidic pH. The optimal shaking speed to grow and to produce antibacterial substance of the B. subtilis HS25 was 160${\sim}$200 rpm. The optimal culture time for antibacterial activities of the bacterium were shown to be in the range of 12-36 hr.

• Microbiology and Biotechnology Letters
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• v.16 no.2
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• pp.119-125
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• 1988

$\beta$-Glucosidase of Cellulomonas sp. CS1-1 in cellular compartment was localized with cell-bound form while Avicelase and carboxymethylcellulase (CMCase) were appeared with extracellular enzyme. Cell growth on cellulose or CMC minimal broth was increased by glucose addition. $\beta$-Glucosidase production on cellobiose or CMC minimal broth was repressed by the addition of glucose. However, on CMC minimal broth, the enzyme production was specially stimulated by cellobiose addition. $\beta$-Glucosidase production was also induced by CMC, starcth and maltose compared with glycerol, arabinose, xylose and trehalose. From the above results, it was concluded that glucose effect on $\beta$-glucosidase biosynthesis showed catabolite repression, but enzyme production was induced by cellobiose, CMC, and starch, indicating that $\beta$-glucosidase is inducible enzyme. Yeast extract stimulated $\beta$-glucosidase production more than peptone and ammonium sulfate. $\beta$-Glucosidase activity was increased with 50mM MgCl$_2$in 10mM potassium phosphate buffer (pH 7.0). Optimum conditions for enzyme activities were pH 6.0 and 42$^{\circ}C$, Km value of $\beta$-glucosidase for p-nitrophenyl-$\beta$-D-glucosidase was 0.256mM and Ki for $\beta$-D(+)-glucose was 9.0mM.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.631-636
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• 1998

Candida lipolytica(C. lipolytica) FM5 was selected as one of the strong saprophytic yeasts isolated from mackerel (Scomber japonicus). The selected strain could produce extracellular proteolytic enzyme. The effective medium for production of proteolytic enzyme by C. lipolytica FM5 was TPPY broth containing Bacto-tryptone $0.5\%$, proteose peptone $0.5\%$, yeast extract $0.25\%$, NaCl $0.5\%$ and $CaCl_2\;0.2\%$. The pattern of proteolytic enzyme production by C. lipolytica FM5 was the almost same as that of growth curve of the strain. Namely, the enzyme production was begun from the early stage of exponential phase and it was reached the highest at the begining of the stationary phase of the yeast growth. The optimum toeperature of the produced proteolytic enzyme was $35^{\circ}C$ and its activity was not significantly changed by pH between 6.5$\~$9.0 and also it was not significantly affected by several kinds of cations such as $Ca^{2+},\;Cu^{2+},\;Fe^{2+}$ and $Mg^{2+}$ but it was affected negatively by some cations such as $Zn^{2+},\;Mn^{2+}$ and $K^+$.

• KSBB Journal
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• v.24 no.4
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• pp.334-340
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• 2009

For the isolation of a plant growth-promoting rhizobacteria, strain YK-5 was selected from approximately 400 thermostable strains isolated from special soil samples. Strain YK-5 produced an antifungal compound, and optimum carbon and nitrogen sources for the production of the antifungal compound were investigated against Aspergillus flavus as a test strain. Modified LB medium containing 1% peptone, 1% yeast extract and 5% black sugar was determined to be the optimal medium for growth and antifungal compound production. Culture broth of strain YK-5 potently inhibited growth of the phytopathogenic fungus Fusarium oxysporum KACC 40052 for 7 days. The plant growth-promotion function of strain YK-5 was tested against radish and rice in pot trials. Leaf number, plant height and root length in YK-5-treated radish markedly exceeded (> 60%) those of untreated radish. Leaf length and white rootlet development were markedly more prominent than in commercially-treated rice plants. Strain YK-5 was determined to be Bacillus subtilis YK-5 by physiological, chemotaxonomical, and phylogenetical analyses.

• Korean Journal of Plant Resources
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• v.15 no.2
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• pp.135-143
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• 2002

The results of examining characteristics of mycelial growth and culture condition for determining the condition of artificially culturing Inonotus obliqua (chaga) are as follows. 1) Mycelial growth and density oft, oblique were the highest in the medium of BDA (Birch Dextrose Agar; 66.3mm/10d) followed by the order of GDA, PDA, CDA, PODA, ODA, YM, MCM, MEA (pH 7.0), CHA, and MEA (pH 4.7). 2) Optimal temperature for the mycelial growth and density of 1. obliqua were shown to be 30$^{\circ}C$, but the mycelia were dead at 40$^{\circ}C$. the mycelial growth and density of KNAC3005 strains was the highest at 30$^{\circ}C$(66.3mm/10d) followed by the order of 25, 20, 15, 35, 10, and 5$^{\circ}C$. 3) Optimal pH for the mycelial growth and density were revealed to be 6.0 (88.4mm/10d). Above or below pH 6.0, the mycelial growth and density were shown to be retarded. 4) Optimal carbon, nitrogen and organic acid sources for the spawn growth of 40 were maltose (331mg/25$m\ell$/15d), peptone (347mg/25$m\ell$/15d), and glutamic acid (357mg/25$m\ell$/15d), respectively. Optimal level of biotin was 370mg/15d and optimal C/N ratio was 40.

• The Korean Journal of Mycology
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• v.33 no.1
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• pp.22-29
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• 2005

The main objectives of this research were to study the cultural and nutritional characteristics of Tricholoma matsutake and to establish its liquid culture system. The optimum growth of T. matsutake was observed in HA and TMM agar media. Similarly highest growth was observed in PDB and TMM liquid media. The optimal temperature for the mycelial growth was $25^{\circ}C$. The most suitable carbon source was dextrin among 12 different carbon sources tested. Yeast extract and peptone were best nitrogen sources among 17 different sources tested. The optimum mineral salts were $Fe_{2}(SO_{4})_{3}{\cdot}H_{2}O$ and KCl among 9 different sources tested. Shaking culture gave higher mycelial growth compared to stationary culture. Similarly, optimum medium amount for shaking culture was 100 ml per 250 ml flask. The highest mycelial growth was obtained when $5{\sim}7$ mycelial discs were inoculated in 100 ml of medium and incubated for $8{\sim}9$ weeks, respectively. The highest proportion of mycelial growth was observed at 40 : 1 ratio of medium to inoculum volume in 8 l air-lift fermenter.

• The Korean Journal of Mycology
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• v.44 no.3
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• pp.138-144
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• 2016

Twelve unrecorded yeasts, Pseudozyma prolifica HL9-1, Trichosporon coremiiforme NS19-2, Candida cretensis SA4-1, Cryptococcus diffluens TJ4-3, Cryptococcus pinus YB17-2, Candida vartiovaarae DD2-5, Pichia galeiformis DM3-5, Candida pseudolambica JW2-3, Trichosporon xylopini NS5-1, Trichosporon moniliiforme NS5-7, Tetrapisispora iriomotensis NS14-2, and Tetrapisispora nanseiensis SA17-1, were screened among 97 yeasts from soils of Chungcheongnam-do and Daejeon metropolitan city, Korea. These yeasts were oval or ellipsoidal and had a budding system for vegetative reproduction. They grew well in yeast extract-peptone-dextrose (YPD) medium and, in particular, Tetrapisispora iriomotensis NS14-2 and Candida cretensis SA4-1 grew well in 10% NaCl-containing YPD broth. Nine strains, including Trichosporon coremiiforme NS19-2, assimilated xylose and four yeast strains, such as Candida vartiovaarae DD2-5, also assimilated lactose. Physiological functionalities of cell-free extracts and supernatants from two halophilic unrecorded yeasts, Candida cretensis SA4-1 and Tetrapisispora iriomotensis NS14-2, were investigated. Cell-free extracts from Candida cretensis SA4-1 and Tetrapisispora iriomotensis NS14-2 exhibited 71.3% and 68.4% antihypertensive angiotensin I-converting enzyme inhibitory activity.