• Korean Chemical Engineering Research
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• v.47 no.2
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• pp.220-229
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• 2009

Strain improvement and morphology investigation in bioreactor cultures were undertaken in suspended cultures of Phellinus linteus mycelia for mass production of protein-bound polysaccharides(soluble ${\beta}$-D-glucan), a powerful immuno-stimulating agent. Phellineus sp. screened for this research was identified as Phellinus linteues through ITS rDNA sequencing method and blast search, demonstrating 99.7% similarity to other Phellinus linteus strains. Intensive strain improvement program was carried out by obtaining large amounts of protoplasts for the isolation of single cell colonies. Rapid and large screening of high-yielding producers was possible because large numbers of protoplasts ($1{\times}10^5{\sim}10^6\;protoplasts/ml$) formed using the banding filtration method with the cell wall-disrupting enzymes could be regenerated in relatively high regeneration frequency($10^{-2}{\sim}10^{-3}$) in the newly developed regeneration medium. It was demonstrated that the strains showing high performances in the protoplast regeneration and solid growth medium were able to produce 5.8~6.4%(w/w) of ${\beta}$-D-glucan and 13~15 g/L of biomass in stable manners in suspended shake-flask cultures of P. linteus mycelia. In addition, cell mass increase was observed to be the most important in order to enhance ${\beta}$-D-glucan productivity during the course of strain improvement program, since the amount of ${\beta}$-D-glucan extracted from the cell wall of P. linteus mycelia was almost constant on the unit biomass basis. Therefore we fully investigated the fungal cell morphology, generally known as one of the key factors affecting cell growth extent in the bioreactor cultures of mycelial fungal cells. It was found that, in order to obtain as high cell mass as possible in the final production bioreactor cultures, the producing cells should be proliferated in condensed filamentous forms in the growth cultures, and optimum amounts of these filamentous cells should be transferred as active inoculums to the production bioreactor. In this case, ideal morphologies consisting of compacted pellets less than 0.5mm in diameter were successfully induced in the production cultures, resulting in shorter period of lag phase, 1.5 fold higher specific cell growth rate and 3.3 fold increase in the final biomass production as compared to the parallel bioreactor cultures of different morphological forms. It was concluded that not only the high-yielding but also the good morphological characteristics led to the significantly higher biomass production and ${\beta}$-D-glucan productivity in the final production cultures.

• Journal of Mushroom
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• v.13 no.3
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• pp.212-216
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• 2015

A new commercial strain "Mongdol" of oyster mushroom was developed by hyphal anastomosis. It was improved with hybridization between monokaryotic strain derived from Pleurotus ostreatus ASI 0627 and dikaryotic strain derived from P. ostreatus ASI 2929. The optimum temperature of mycelial growth and fruiting body development were $25{\sim}30^{\circ}C$ and $12{\sim}18^{\circ}C$, respectively. When two different media including PDA (potato dextrose agar medium) and MCM (mushroom complete medium) were compared, the mycelial growth of this mushroom was faster in MCM than in PDA. Similar result was observed with the control strain P. ostreatus ASI 2504. Analysis of the genetic characteristics of the new cultivar "Mongdol" showed a different DNA profile as that of the control strain ASI 2504, when RAPD (Random Amplified Polymorphic DNA) primer URP3 and URP6 were used. Fruiting body production per bottle was about 106 g using demonstration farms. The color of pileus was blackish gray and the stipe was long. Therefore, we expect that this new strain "Mongdol" will satisfy the consumer's demand for high quality mushrooms.

• Journal of Korean Society of Forest Science
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• v.86 no.3
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• pp.279-287
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• 1997

This study was carried out to identify the analysis of vegetation-environment relationships of the coniferous forests in subalpine districts of Mt. Chiri by two-way indicaton species analysis(TWINSPAN) and CCA. The results are summarized as follows; The subalpine coniferous forest in Mt. Chin was classified Abies koreana community group by the TWINSPAN method. The Abies koreana community group was classified Abies koreana-Pinus densiflora, Abies koreana-Quercus mongolicd and Abies koreana-Picea jezoensis. The Abies koreana-Quercus mongolica community classified into two subcommunities, typical and Pinus koraiensis subcommunity. The Abies koreana-Picea jezoensis community classified into three subcommunities such as typical, Taxus cuspidate and Cornus controversa subcommunity. The subalpine conifers commnities in Mt. Chiri could be classified into six vegetation units, which consisted of three vegetation communities and five subcommunities. The relationship between vegetation community and influencing environmental factors was analyzed by using the CCA ordination method. It was found that altitude, concentrations of $Ca^{++}$ and $Mg^{++}$ in soil were, major environmental variables, which influence the distribution of vegetation community in the first axis, and $Ca^{++}$ and altitude in the second axis. In the relations of communities and environmental factors by CCA, the optimal ecological habitats of Abies koreana-Pinus densiflora community could be located at low elevations, in which $Ca^{++}$ and $Mg^{++}$ are rich. Abies koreana-Quercus mongolica community prefers the sites in mid-elevation zone, in which $Ca^{++}$ and $Mg^{++}$ are medium level in soil. The optimum site for Abies koreana-Pinus koraiensis community and Abies koreana-Taxus cuspidata community could be high elevations in which $Ca^{++}$ and $Mg^{++}$ are poor. Abies koreana-Cornus controversa community is found in the site at low elevations where $Ca^{++}$ and $Mg^{++}$ are medium.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.465-474
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• 1999

RNase activity of Saccharomyces cerevisiae ATCC 7754 was investigated to obtain strains with high ribonucleic acid (RNA) content. The yeast strain contained two RNase activities; an acidic RNase with a optima of pH $3{\sim}4$ and an alkaline RNase with a optima pH 9. The acidic RNase activity was inhibited by $0.08\;M\;HgCl_{2}$ most drastically. The alkaline RNase activity was inhibited by 2.0 M NaCl or KCl, while enhanced by addition of $0.05\;M\;CaCl_{2},\;0.02\;M\;ZnSO_{4},\;or\;0.008\;M\;HgCl_{2}$. Various mutants of Saccharomyces cerevisiae ATCC 7754 were isolated by ethylmethane sulfonate (EMS) treatment or $\gamma$-ray/ultra violet irradiation. Among the mutants that were sensitive to high concentration of KCl which inhibits alkaline RNase, B24 was selected for high RNA content per culture volume. Growth characteristics of the mutant were comparable to those of the mother strain with optimum growth at pH $4.5{\sim}5.5$. The mutant accumulated higher content of RNA than the mother strain when glucose was used as the carbon source. However, both growth rate and total RNA content of the mutant were higher in molasses medium than in glucose medium. RNA content of the mutant increased rapidly during the early stage of growth, and then decreased gradually until the culture reached stationary phase by a fed-batch culture in a 5 L jar fermenter. Maximal cell harvest and the final RNA content using the mutant B24 were 69.6 g/L culture broth and 19.8 g/100 g of the dry cell while those using the mother strain were 68 g/L culture broth and 16.1 g/100 g of dry cell, respectively.

• Korean Journal of Plant Resources
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• v.10 no.4
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• pp.401-410
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• 1997

This experiment was conducted to investigate the opimum media, media amount and planting density of nutri-culture for the high quality and yield of wild vegetable, Liguliaria fischeri Turez. The fried rice hull was recognized best media among perlite, sand and fried rice hull for nutri-culture of Ligularia fischeri Turcz. The yield on fried rice hull media at early growing stage was lower, but higher than in other media at late growing stage. Therefore, total yield in fried rice hull media was 15-29% higher than that of the existing perlite media. Growth and yield of Ligularia fischeri Turcz. were not significantly different between medium amounts, therefore considering economical efficiency and stability, the optimum medium amount was 105 $\iota/m^3$, Yield by planting density increased in the high density and 50 plants/$m^2$ was considered as proper planting density in nutri-culture of Liguliaria fishcheri Turcz.

• Korean Journal of Plant Resources
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• v.25 no.2
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• pp.225-231
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• 2012

To figure out optimum culturing condition for $in$ $vitro$ yam ($Dioscorea$ $opposita$ Thunb.) production, various media components and environmental controls were evaluated, effective temperature, light condition and timing of the liquid media replacement for multiplication of yam in liquid culture were determined in this study. There was no visible difference detected for $15^{\circ}C$ and $25^{\circ}C$ temperature conditions. At $25^{\circ}C$, continuous light condition was more effective compared to 16 hour light/ 8 hour dark condition. Effect of media replacement was tested, and approximately 5 more microtubers obtained and 70% of increase in weight was detected when media replacement was performed. Timing for media replacement was tested at 2, 4, 6, 8, and 10 weeks after initial culture for 12 weeks. Considering both number and weight of microtubers, replacement of media 6 weeks after initial culture was most effective. In terms of component of media, significant increase in weight of microtubers was observed in MS media containing sucrose $60g{\cdot}L^{-1}$. In summary, the most effective condition for $in$ $vitro$ propagation of chinese yam is replacing medium 6 weeks after initial inoculation with MS medium containing sucrose $60g{\cdot}L^{-1}$ in continuous light condition.

• Polymer(Korea)
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• v.30 no.6
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• pp.498-504
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• 2006

A suspension polymerization of styrene In aqueous phase was employed to study if polystyrene particles ranging from 1 to $20{\mu}m$ can be produced. Hydrophobic silica was selected as a stabilizer and azo-bisisobutyronitrile (AIBN) as an initiator. Polymerization reaction was carried out at a selected temperature in the range of $65{\sim}95^{\circ}C$. Stabilizer concentration was varied from 0.17 to 3.33 wt% compared to the water while the concentration of the initiator was raised from 0.13 to 6.0 wt% compared to the monomer. Dispersion of hydrophobic silica into the water phase was achieved by precise control of pH. Optimum dispersion of silica was obtained at pH 10. Average particle diameter decreased with increasing amounts of stabilizer concentration initially, exhibiting the minimum average diameter at 1.67 wt% of stabilizer concentration, after which it started to Increase. It is speculated that an excessive presence of stabilizer encouraged a secondary reaction in the reaction medium, which led to particle agglomeration, and as a result an increase in average particle diameter. Molecular weight was found to be independent of stabilizer concentration between 0.13 and 1.00 wt% whereas, it increased when stabilizer concentration exceeded 1.67 wt%. Variation of molecular weight was probably caused by the reduced activity and efficiency of initiator due to the high concentration of silica, and the secondary reaction in the reaction medium, as well. An increase in the Initiator concentration and/or reaction temperature resulted in an increase in both reaction rate and particle diameter. Consequently, we have confirmed that spherical polystyrene particles with $1{\sim}20{\mu}m$ in diameter can be prepared by careful selection of the concentration of stabilizer, initiator, pH and reaction temperature.

• Horticultural Science & Technology
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• v.29 no.1
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• pp.16-22
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• 2011

In developing soil wetting agent using polyoxyethylene nonylphenyl ether (PNE) and polyoxyethylene castor oil (1:1; v/v), the effect of application rates on changes in concentration of PNE, initial wetting of peatmoss + perlite (7:3) medium, and growth of hot pepper (Capsicum annuum L. 'Knockwang') plug seedlings were investigated. The elevation of application rates of wetting agent increased the amount of water retained by the root media. The treatment of 2.5 $mL{\cdot}L^{-1}$ showed similar water retention to + control ($AquaGro^L$ 3.0 $mL{\cdot}L^{-1}$). Most of the liquid wetting agent (LWA) incorporated during the medium formulation leached out in the first and second irrigation, then it decreased gradually until 10 times in irrigation. In investigation of the influence of LWA on position of water infiltrating into root media, the vertical water movements in treatments of 0.5, 1.0, and 1.5 $mL{\cdot}L^{-1}$ were much faster than those in 0.0 $mL{\cdot}L^{-1}$ (-control), but relative speed of water movement decreased by the elevation in application rate of LWA to 2.0 or 2.5 $mL{\cdot}L^{-1}$. The evaporative water loss of root media that to contained various rate of LWA and irrigated to reach container capacity was the fastest in -control among the treatments and it delayed as the application rate of LWA was elevated. The plant height of 22.2 cm in 0.5 $mL{\cdot}L^{-1}$ and stem diameter of 3.26 mm in 1.0 $mL{\cdot}L^{-1}$ were the highest among the treatments tested. The treatment of 1.0 $mL{\cdot}L^{-1}$ also had the heaviest fresh and dry weights such among treatments tested as 3.08 g and 0.861 g per plant, respectively. The elevated application rate over than 1.5 $mL{\cdot}L^{-1}$ resulted in decreased seedling growth. The results mentioned above indicate that optimum application rate of LWA is 1.0 $mL{\cdot}L^{-1}$.

• Korean Journal of Agricultural Science
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• v.4 no.2
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• pp.283-316
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• 1977

In an attempt to obtain a basic information to develop an effective integrated system of controlling sheath blight of rice in Korea, the transition of this disease, the variation of cultural characters and pathogenicity of the pathogen, environmental conditions affecting the disease outbreak and varietal resistance have been investigated. 1. Rice sheath blight which has been minor disease in the past was widely spread, especially since 1971. This disease has promptly spread all over the country and infected 65.2% of total rice growing area in 1976. Various factors are considered to be related to such transition of this disease. Above all, increace of application of nitrogenous fertilizer, early season and earlier cultivation of rice, introduction of more susceptible "Tongil" varieties etc. must be important factors influencing the outbreak of this disease. 2. Great variations in cultural characteristics-such as mycelial growth rate, color of the medium, amount of the aerial mycelium, shape and color of the sclerotia- and in the pathogenicity of isolates of the pathogen, Thanatephorus cucumeris Dank were observed. The optimum temperature for mycelial growth also varied with isolates, from $25^{\circ}C$ to $30^{\circ}C$. There were not necessarily any correlation between curtural characteristics and pathogenicity of isolates of Thanatephorus cucumens. 3. Mycelial grow th of isolates of Thanatephorus cucumens on the PDA medium were correlated with the air temperatures of the region where the isolates were collected. The isolates from the regions with high temperature grew well on PDA medium at $35^{\circ}C$ than those from the region with low temperature, on the other hand, the isolates from the regions with the low temperature grew well on the same medium at $12^{\circ}C$ than those from the regions with high temperature. 4. Pectin polygalacturonase (PG) and cellulase (Cx) were most active on the 3rd day after inoculation on the leaves of rice plant with Thanatephorus cucumeris, whereas pectin methylestrase (PE) was most active on the 4th day after inoculation. Relationship between the activities of PE of isolates and the strength of pathogenicity of isolates was obtained, but PG and cellulase activities were not correlated with pathogenicity of isolates. 5. The tolerence of sclerotia from in-vitro culture to low temperature varied with their water content, the dried cultural sclerotia were more tolerent than wet ones, Dried cultural sclerotia maintained almost 100% germinability for 45 days at $-20^{\circ}C$, whereas wet sclerotia lost viability at $-5^{\circ}C$. The germination ratio of the sclerotia after overwintering changed from 18% to 70% according to the water content of the test paddy fields and the ratio was low in wet paddy condition. 6. To investigate the host range of this fungi in and near paddy field, 17 weeds were inoculated with fungi. The lesions of sheath blight disease was obserbed on Sagittaria trifolia L., Echinochloa crusgalli P. Beauv., Monochoria vaginal is Presl, Polygonum Hydropiper L., Eclipta prostrata L., Digitaria sanguinalis Scapoli. 7. When the level of nitrogen applied was doubled over standard level, total nitrogen content in rice sheath increased, ami when silicate was applied, starch content in rice sheath decreased, inducing the rice plants more susceptible to sheath blight disease. Increased dressing of potash ferilizer reduced the incidence of sheat blight disease. 8. The percentage of infected stems in the early period increased more in the narrow hill plot than in the wide hill plot, but in the late period this tendency was inversed; the percentage of infected stems as well as severity in the wide hill plot increased more compared to the narrow hill plot, and the disease severity in the one plant per hill plot was also low. The number of stems in the wide hill plot was more than the number of stems in the narrow hill plot. This indicates that the microclimate, such as the relative humidity, in the narrow hill plot was more favorable for the development of this disease. 9. There was a high negative correlation between the disease severity of varieties to the sheath blight and the maturity of the varieties, that is, the early varieties were more susceptible than the late ones, and much-tillering varieties usually showed more infection than less tillering varieties. 10. No relationship was obtained between the percentage of infected stems in the early period and the severity after heading, whereas a distinct relationship was obtained between former and latter after Aug. 10.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.192-198
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• 2012

Experiments were conducted to investigate the optimum concentration of nutrient solution in hydroponics for strawberry 'Ssanta' bred at Gyongsangbuk-do Agricultural Research & Extension Services. Nutrient solutions for strawberry, which made by Yamazaki, were supplied EC (Electrical Conductivity) 0.6, 0.8, 1.2, and $1.8dS{\cdot}m^{-1}$ after planting on cocopeat medium during experiment period. Growth of shoot of strawberries did not show statistical differences among treatments. Fruit length showed the longest in EC $0.8dS{\cdot}m^{-1}$ in all clusters. In the second flower cluster, fruit length showed longer in EC 0.8 and $1.2dS{\cdot}m^{-1}$ than EC 0.6 and $1.8dS{\cdot}m^{-1}$. In the third flower cluster, it showed the longest in EC 0.8 and $1.2dS{\cdot}m^{-1}$, followed by 0.6 and $1.8dS{\cdot}m^{-1}$. The longest was in EC $0.8dS{\cdot}m^{-1}$ and the shortest in EC $1.8dS{\cdot}m^{-1}$ in the fourth flower cluster. Fruit diameter did not show significant differences among treatments, but longest in EC 0.8 and $1.2dS{\cdot}m^{-1}$ in all clusters. The heaviest mean fruit weight appeared in EC $0.8dS{\cdot}m^{-1}$ in all flower clusters. And heavier in EC $1.2dS{\cdot}m^{-1}$ in the second and third clusters. Also the weight was significantly light in plants grown in EC 0.6 and $1.8dS{\cdot}m^{-1}$ in the second and third cluster. Soluble solids of fruit was the highest in EC $0.6dS{\cdot}m^{-1}$ in all clusters. As the results, we came to the conclusion that the optimum EC for strawberry 'Ssanta' was EC $0.8{\sim}1.2dS{\cdot}m^{-1}$ in this experiment.