• Journal of Mushroom
• /
• 제20권4호
• /
• pp.235-240
• /
• 2022

This study aimed to replace the imported Chinese complete medium for Lentinula edodes with a newly-developed complete medium that is suitable for export as well. Three media compositions that supported fast mycelium growth and higher density, compared to that in the control, were chosen. Culture in the T13 medium reduced the incubation period for 'Nongjingo' by 12 days and for 'Cham-aram' by 10 days, compared to that required for the control; in addition, the number of days required for browning was greatly reduced for both varieties. The quantity of each mixed medium was increased according to the composition from the 1^st to the 5^th cycle by 5.9% for 'Nongjingo' and 12.6% for 'Cham-aram' in T13, compared to that in the control. A mixed medium comprising oak sawdust + Douglas fir sawdust + corn flour (40:40:20, v/v) was selected as the most suitable complete medium.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제8권2호
• /
• pp.83-88
• /
• 2003

A cellulose-producing strain isolated from rotten apples was identified as Gluconacetobacter hansenii based on its physiological properties and the 16S rDNA complete sequencing method, and specifically named Gluconacetobacter hansenii PJK. The amount of bacterial cellulose (BC) produced by G. hansenii PJK in a shaking incubator was 1.5 times higher than that produced in a static culture. The addition of ethanol to the medium during cultivation enhanced the productivity of bacterial cellulose, plus the supplementation of 1% ethanol into the culture medium made the produced BC aggregate into a big lump and thus protected the bacterial-cellulose-producing G. hansenii PJK cells in the shear stress field from being converted into non-cellulose-producing (Cel) mutants. Cells subcultured three times in a medium containing ethanol retained their ability to produce BC without any loss in the production yield.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• 제54권6호
• /
• pp.409-416
• /
• 2005

For broadband high-data-rate power line communication with the allocated frequency bandwidth from 2 to 30 MHz on medium voltage (MV) distribution power lines, a signal coupling unit is developed. The coupling unit is composed of a coupling capacitor for coupling communication signal, a drain coil, and an impedance matching part. The coupling capacitor made of ceramic capacitor is designed for transmission property of better than 1 dB in the frequency range. The drain coil is used for preventing low frequency high voltage from junction of medium voltage power line in case that a coupling capacitor is not working properly any more. Also, using ferrite core, a novel broadband impedance matching transformer is developed. A complete coupling unit with a coupling capacitor, a drain coil, and a matching transformer is housed by polymer for good isolation and distinguishing from high voltage electric facilities. Each is fabricated and its frequency behavior is tested. Finally, complete signal couplers are equipped in a MV PLC test bed and their performance are measured. The measurement shows that the coupling capacitor works excellently.

• Microbiology and Biotechnology Letters
• /
• 제24권6호
• /
• pp.749-755
• /
• 1996

From the soil collected from provincial area of South Korea, a microorganisms which have been shown good growth in the minimal poultry feces extract medium was isolated. Supplement of glucose to the poultry feces extract medium helped the complete uptake of soluble protein by microorganism. Uric acid in the poultry feces extract medium could be completely degraded during the microbial growth. Maximum cell growth (3.8 $\times$ 10$^{9}$ CFU/ml) obtained at 36 hours of incubation after inoculation. Uric acid was degraded faster in minimal medium than in the glucose complement medium. VFA (volatile fatty acid), which are known as major compounds of poultry feces odor, were almost removed from the minimal poultry feces extract medium. Glucose supplement to the minimal medium enhanced the growth of microbial cells. Addition of 4% of glucose and 4% of neopeptone to the minimal poultry feces extract medium helped the maximal growth of cells.

• Journal of the Korea Society for Simulation
• /
• 제12권2호
• /
• pp.75-89
• /
• 2003

This paper describe numerical experiments with solitary beams in a self focusing Kerr medium with fast response. Through formal analogies, it compare this results on the phase sensitivity of beam collision with known predictions about one dimensional soliton interaction. For incoherent oblique beam interaction, there occurs a non-periodic coupled-mode type transfer of energy, resulting in complete transmission each beam through the other one.

• Structural Engineering and Mechanics
• /
• 제38권5호
• /
• pp.593-618
• /
• 2011

This paper deals with the problem of the determination of the response of a viscoelastic Bernoulli-Navier beam, which is resting on an elastic medium. Assuming uniaxial bending, the displacement of the beam axis is governed by an integro-differential equation. The compatibility of the displacements between the beam and the elastic medium is imposed through an integral equation. In general and in particular in the case of a Boussinesq medium, the solution has to be pursued numerically. On the contrary, in the case of a Winkler's medium the compatibility equation becomes a linear finite relationship, which allows finding an original analytical solution of the problem for both hereditary and aging behavior of the beam. Some numerical examples complete the paper, in which a comparison is made between the hereditary and the aging model for the creep of the beam.

• Mycobiology
• /
• 제38권3호
• /
• pp.189-194
• /
• 2010

This study investigated the cultural characteristics of Shimizuomyces paradoxus in different nutritional and environmental conditions. The highest mycelial growth was observed in Schizophyllum (mushroom) genetics complete medium plus yeast extract agar medium, and the optimal temperature and pH were $25^{\circ}C$ and pH 8.0, respectively. The optimal carbon and nitrogen sources were 1% dextrose and 1% peptone in agar. However, in liquid culture the highest dry mycelium weight was found for the potato dextrose agar and potato sucrose agar broths. The optimum inoculum size was five mycelial discs (5 mm) per 100 mL of broth, and the optimum liquid culture period was 25 days. This is the first ever report of S. paradoxus cultural characteristics.

• Journal of Microbiology and Biotechnology
• /
• 제19권4호
• /
• pp.409-415
• /
• 2009

Galactomyces geotrichum MTCC 1360 degraded the Scarlet RR(100 mg/l) dye within 18 h, under shaking conditions(150 rpm) in malt yeast medium. The optimum pH and the temperature for decolorization were pH 12 and $50^{\circ}C$, respectively. Enzymatic studies revealed an induction of the enzymes, including flavin reductase during the initial stage and lignin peroxidase after complete decolorization of the dye. Decolorization of the dye was induced by the addition of $CaCO_3$ to the medium. EDTA had an inhibitory effect on the dye decolorization along with the laccase activity. The metabolites formed after complete decolorization were analyzed by UV-VIS, HPLC, and FTIR. The GC/MS identification of 3 H quinazolin-4-one, 2-ethylamino-acetamide, 1-chloro-4-nitro-benzene, N-(4-chloro-phenyl)-hydroxylamine, and 4-chloro-pheny-lamine as the final metabolites corroborated with the degradation of Scarlet RR. The phytotoxicity study revealed the nontoxic nature of the final metabolites. A possible degradation pathway is suggested to understand the mechanism used by G. geotrichum and thereby aiding development of technologies for the application of this organism to the cleaning-up of aquatic and terrestrial environments.

• Korean Journal of Microbiology
• /
• 제22권3호
• /
• pp.135-142
• /
• 1984

The effect of biotin on the growth and sporulation of Bacillus subtilis SNU816 was investigated. When B. subtilis SNU816 was cultured on glucose as a sole carbon source, the growth was retarded markedly and usually ceased at early log phawe. But by addition of biotin to this medium, normal, rapid growth was restored. The growth rate was increased proportionally according to the concentration of exogenous biotin until it reached to 0.05㎍/ml, at which about three fold rapid growth was achieved. Also biotin was required for optimum sporulation for it facilitated the complete utilization of both glucose(Glc) and glutamic acid(Glu). Without biotin in Glc+Glu medium, about 40% of glutamic acid was remained unutilized. The dipicolinic acid content of cells cultured in Glc+Glu medium without biotin was markedly small and sporulation was suppressed before free spore release. Since biotin could be partiallyreplaced by one of TCA cycle intermediates such as oxalacetic acid, citric acid, or glutamic acid in enhancing growth in Glc medium, it was postulated that this strain might have a defect in converting pyruvate to oxalacetate which process is known to be mediated by pyruvate carboxylase that requires biotin as a cofactor.

• Reproductive and Developmental Biology
• /
• 제29권4호
• /
• pp.241-245
• /
• 2005

Porcine oviduct epithelial cells (POEC) are widely used in co-culture experiments to improve early embryonic development, in vitro fertilization in embryo transfer programs for domestic animals and in vitro maturation of immature germ cells. POEC were mechanically isolated and cultured in tissue culture medium 199. Cells grew continuously, and confluent monolayers were formed after 7 days. After forming confluent monolayer of epithelial cells, supernatant was collected as the condition medium for maturing round spermatids in vitro. Round spermatids were also separated mechanically and cultured in the POEC condition medium. In this study we observed that $20\%$ of round spermatid cultured were matured into elongating spermatid after 24 h, and about $10\%$ of round spermatid cultured showed complete elongation (elongated spermatid) within $24\~48$ h of in vitro culture. No further development was observed within $50\~72$ h and transformed cells lost their viability after 72 h. These preliminary findings suggest that the condition medium from POEC may be possible to overcome the round spermatid block by improving the milieu of culture system.