• KSBB Journal
• /
• v.4 no.2
• /
• pp.162-166
• /
• 1989

When various strains of Streptomyces griseus and S. galbus were examined for the ability on the production of streptomycin in tryptic soy(TS) broth, S. griseus ATCC 27001 was found to be the best. S. griseus ATCC 12475 and ATCC 23345 showed also good growth and favorable production of streptomycin. Examination of various complex media reported in fermentation literatures for the industrial production of streptomycin indicated that glucose-soybean media-sodium chloride (GSS) broth and K (Chucken) broth gave higher yields of streptomycin than others studied by us. Examination of the ingredients of media producing streptomycin in high yield indicated that some components in soybean activated the production of streptomycin. Addition of meat extract enhanced the yield of streptomycin but it could be substituted with distillers solubles without much effect on the yield. Addition of corn steep liquor decreased the production of streptomycin.

• KSBB Journal
• /
• v.25 no.4
• /
• pp.401-407
• /
• 2010

We established a strategy for bioethanol production using the hydrolysate of rape stem, in which the inhibitor cocktail was added intentionally. The final goal of this study was to circumvent the detoxification process when the hydrolysate of lignocelluloisic biomass contained the toxic substances in high concentration. When six yeast strains were examined, Sacchromyces cerevisiae ATCC 96581 and Pichia stipitis CBS 7126 were relatively resistant to inhibitor cocktail. Then, using strains 96581 and 7126, we designed a process strategy for bioethanol production, assuming that the concentration of toxic substance in the hydrolysate of rape stem was remarkably high. When strains 96581 and 7126 were inoculated simultaneously, it was observed that strain 7126 produced bioethanol as well as strain 96581, although the concentration of inhibitor cocktail was 18.2% (v/v). Finally, throughout this co-cultivation of strains 96581 and 7126, bioethanol was produced about 6.0 (g/L), and bioethanol yield reached at 0.4 (g-bioethanol/g-reducing sugar) (78.4% of theoretical value).

• Journal of Mushroom
• /
• v.19 no.4
• /
• pp.347-352
• /
• 2021

In this study, to select suitable shiitake strains in Jangheung region for domestic strains of Lentinula edodes for log cultivation, a total of five different Korean strains(Chunbaegko, Sanjo 303ho, Poongnyunko, Baekhwahyang, Soohyangko) and two Japanese strains (Mori 290, Moriyujiro) were selected and a cultivation test was conducted to select suitable strains. As a result of the yield, Sanjo 303ho produced 40.9 kg, which was superior to 39.2 kg for Mori 290 and 37.7 kg for Moriyujiro. As for the quality characteristics, it was confirmed that Baekhwahyang had a hemispherical shape, and high quality fruit bodies. In conclusion, Sanjo 303ho, which has excellent production, and Baekhwahyang, which is advantageous for producing high-quality shiitake, were selected in Jangheung region for domestic strains.

• Earthquakes and Structures
• /
• v.9 no.4
• /
• pp.831-849
• /
• 2015

Seismic-design procedures for walls require that the confinement in the critical (plastic hinge) regions should extend over a length in the compression zone of the cross section at the wall base where concrete strains in the Ultimate Limit State (ULS) exceed the limit of 0.0035. In a performance-based framework, confinement is linked to required curvature ductility so that the drift demand at the performance point of the structure for the design earthquake may be met. However, performance of flexural walls in the recent earthquakes in Chile (2010) and Christchurch (2011) indicates that the actual compression strains in the critical regions of many structural walls were higher than estimated, being responsible for several of the reported failures by toe crushing. In this study, the method of estimating the confined region and magnitude of compression strain demands in slender walls are revisited. The objective is to account for a newly identified kinematic interaction between the normal strains that arise in the compression zone, and the lumped rotations that occur at the other end of the wall base due to penetration of bar tension yielding into the supporting anchorage. Design charts estimating the amount of yield penetration in terms of the resulting lumped rotation at the wall base are used to quantify the increased demands for compression strain in the critical section. The estimated strain increase may exceed by more than 30% the base value estimated from the existing design expressions, which explains the frequently reported occurrence of toe crushing even in well confined slender walls under high drift demands. Example cases are included in the presentation to illustrate the behavioral parametric trends and implications in seismic design of walls.

• ALGAE
• /
• v.28 no.2
• /
• pp.203-211
• /
• 2013

Dunaliella salina and Dunaliella bardawil are well known for carotenogenesis, the overproduction of carotenoids, under stress conditions. The effect of high light (HL) and low light (LL) on the growth, morphology, photosynthetic efficiency, and the ${\beta}$-carotene and zeaxanthin production of D. salina CCAP 19/18 and D. bardawil was investigated and compared. Both strains showed similar growth kinetics under LL growth condition, but D. salina CCAP 19/18 was faster. As the light intensity increased, D. salina CCAP 19/18 cells were elongated and D. bardawil cells became larger. Both strains showed decrease of the maximum quantum yield of PSII ($F_v/F_m$) and election transport rate (ETR) under HL growth condition and D. salina CCAP 19/18 was less liable to the light stress. Both strains had about 1.8 and 5 times difference in the $O_2$ evolution rate at LL and HL conditions, respectively. The ${\beta}$-carotene and zeaxanthin production were increased as the light intensity increased in both strains. D. bardawil was more sensitive to light intensity than D. salina CCAP 19/18. The possible application of D. salina CCAP 19/18 as a carotenogenic strain will be discussed.

• Journal of Microbiology and Biotechnology
• /
• v.31 no.12
• /
• pp.1722-1731
• /
• 2021

The genus Streptomyces is intensively studied due to its excellent ability to produce secondary metabolites with diverse bioactivities. In particular, adequate precursors of secondary metabolites as well as sophisticated post modification systems make some high-yield industrial strains of Streptomyces the promising chassis for the heterologous production of natural products. However, lack of efficient genetic tools for the manipulation of industrial strains, especially the episomal vector independent tools suitable for large DNA fragment deletion, makes it difficult to remold the metabolic pathways and streamline the genomes in these strains. In this respect, we developed an efficient deletion system independent of the episomal vector for large DNA fragment deletion. Based on this system, four large segments of DNA, ranging in length from 10 kb to 200 kb, were knocked out successfully from three industrial Streptomyces strains without any marker left. Notably, compared to the classical deletion system used in Streptomyces, this deletion system takes about 25% less time in our cases. This work provides a very effective tool for further genetic engineering of the industrial Streptomyces.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.21 no.5
• /
• pp.493-504
• /
• 2008

This paper presents a computation of nonlinear elastic strains that may occur in the leaflet of the Edwards MIRA mechanical heart valve by the applied high blood pressure using the finite element analysis methodology. By adopting numerical analysis techniques of the commercial finite element analysis code, NISA, structural analyses of the Edwards MIRA mechanical heart valve are performed for the slight variation of leaflet thickness to get the elastic strains occurring in the leaflet while the high blood fluid pressures are applied to the leaflet surface in order that the maximum stress occurring in the leaflet may be less than the yield stress of the leaflet material(Si-Alloyed PyC). And so, only the geometric non-linearity is assumed because large geometric nonlinear elastic strains are expected rather than material nonlinear strains due to the applied high blood pressure. Computed linear and nonlinear elastic strains are compared to make sure the non-linearity of the computed elastic strain. The comparison result shows that large elastic strains occur clearly in the very thin leaflets as high blood pressures are applied. However, only the linear elastic strains occur for low blood pressures, and also for thick leaflets even for the high blood pressures. Hence the nonlinear structural analysis is very required in the structural design of a mechanical heart valve.

• Journal of Korean Society of Forest Science
• /
• v.85 no.2
• /
• pp.309-315
• /
• 1996

Selective breeding and hybridization were attempted to improve shiitake(Lentinus edodes) strains for bed-log cultivation, and the results obtained are as follows. 1. Thirty five strains collected in Korea and abroad were cultivated for one generation(five years) and fruit body yields were estimated by the amounts produced from $1m^3$ of oak tree(Quercus mongolica) logs. Thus, three high-temperature type strains including FRI 177 showing productivity of $139kg/m^3log$, two mid-temperature type strains including FRI 188 of $120kg/m^3log$, and seven low-temperature type strains including FRI 187 of $96kg/m^3log$ were selected as superior strains. 2. Twelve hybrid strains confirmed as independent strains through indoor-test with hybrid strains made by Di-mon mating method were cultivated for five years(one generation). Among them, FRI 182 and FRI 184 were turned out to be superior strains. FRI 182 of high-temperature type showed the yield of 108kg per $1m^3logs$ and FRI 184 of low-temperature type produced $103kg/m^3log$. 3. There were no significant differences in productivity among high-, mid- and low-temperature types, but some differences appeared among strain groups. The correlation was not shown in productivities between bed-log and sawdust cultivations.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.12
• /
• pp.2009-2018
• /
• 2018

Leuconostoc mesenteroides can be used to produce mannitol by fermentation, but the mannitol productivity is not high. Therefore, in this study we modified the chromosome of Leuconostoc mesenteroides by genetic methods to obtain high-yield strains for mannitol production. In this study, gene knock-out strains and gene knock-in strains were constructed by a two-step homologous recombination method. The mannitol productivity of the pat gene (which encodes phosphate acetyltransferase) deletion strain (${\Delta}pat::amy$), the fk gene (which encodes fructokinase) deletion strain (${\Delta}fk::amy$) and the stpk gene (which encodes serine-threonine protein kinase) deletion strain (${\Delta}stpk::amy$) were all increased compared to the wild type, and the productivity of mannitol for each strain was 84.8%, 83.5% and 84.1%, respectively. The mannitol productivity of the mdh gene (which encodes mannitol dehydrogenase) knock-in strains (${\Delta}pat::mdh$, ${\Delta}fk::mdh$ and ${\Delta}stpk::mdh$) was increased to a higher level than that of the single-gene deletion strains, and the productivity of mannitol for each was 96.5%, 88% and 93.2%, respectively. The multi-mutant strain ${\Delta}dts{\Delta}ldh{\Delta}pat::mdh{\Delta}stpk::mdh{\Delta}fk::mdh$ had mannitol productivity of 97.3%. This work shows that multi-gene knock-out and gene knock-in strains have the greatest impact on mannitol production, with mannitol productivity of 97.3% and an increase of 24.7% over wild type. This study used the methods of gene knock-out and gene knock-in to genetically modify the chromosome of Leuconostoc mesenteroides. It is of great significance that we increased the ability of Leuconostoc mesenteroides to produce mannitol and revealed its broad development prospects.

• Korean Journal of Poultry Science
• /
• v.45 no.3
• /
• pp.175-182
• /
• 2018

The carcass and meat quality of new native chicken strains (A, C, and D) being developed in the Golden Seed Project for Samgyetang were compared with a commercial native chicken (Hanhyup No. 3, H) and Baeksemi (white semi broiler, W) strains. In total, 250 male chicks were raised under the same feeding and raising conditions for 5 weeks. After slaughter, the carcass weight and percentage yield of parts from each strain were measured and the physicochemical quality traits (general composition, color values, fatty acid composition, and sensory evaluation) of breast muscles were comparatively analyzed. The carcass weight (875.10 g) of the W strain was significantly heavier than that of the other native chicken strains, while that of A strain (537.54 g) was the lowest. The percentage yield of breast meat was also higher in the W strain than in the other strains. The fat content of W strain was higher than that of the other native chicken strains. The new native chicken strains (A, C, D) had higher contents of linoleic acid (C18:2) than the H strain. The A and D strains especially showed relatively high content of arachidonic acid (C20:4), a characteristic fatty acid in native chicken meats. On the other hand, the fatty acid composition of C strain was similar to that of the W strain. This study provides important information on specific quality characteristics than can be used to select new native chicken lines for breeding program.