• Microbiology and Biotechnology Letters
• /
• v.26 no.3
• /
• pp.244-249
• /
• 1998

An extracellular polysaccharide, methylan, was produced under the specific conditions by Methylobacterium organophilum from methanol. The specific growth rate of cells was approximately constant regardless of C/N ratio and the specific product yield was maximum at a C/N ratio of 30. Methylan production was suppressed by the deficiency of mineral ions such as Mn$^{++}$ or Fe$^{++}$ ion. The optimal pH for cell growth and methylan production was 7. Whereas the optimal temperature for cell growth was found to be 37$^{\circ}C$, that for methylan production was 3$0^{\circ}C$. The methanol concentration above 4% completely inhibited the cell growth. The initial methanol concentration for the maximal production of methylan was 0.5% (v/v) and above this concentration, methylan production was markedly inhibited. To overcome the substrate toxicity and inhibition for both cell growth and methylan production, a fed-bach culture of intermittent feeding within 5 g/l methanol was conducted under the optimal culture condition. Methylan production of was stimulated by nitrogen limitation and methylan was accumulated up to 8.7 g/1 and cell mass also increased up to 12.4 g/l.

• Ocean and Polar Research
• /
• v.38 no.1
• /
• pp.47-57
• /
• 2016

Effects of environmental factors on the zoospore release and germling growth of Chaetomorpha linum were examined. Zoospore release and germling growth experiments were carried out under a combination of temperatures ${\times}$ irradiances, and a single factor of irradiances, salinities, daylength and nutrients (nitrogen, phosphorus). Zoospore release was maximal under condition of $20^{\circ}C{\times}100{\mu}mol\;photons\;m^{-2}s^{-1}$ in a factorial experiment (temperatures ${\times}$ irradiances), at $100{\mu}mol\;photons\;m^{-2}s^{-1}$ in irradiance experiment and at 34 psu in salinity conditions. After 24 days in culture, germling growth was maximal at $25^{\circ}C{\times}100{\mu}mol\;photons\;m^{-2}s^{-1}$ in temperatures ${\times}$ irradiances and at normal seawater (34 psu) in salinity. Germling growth is faster at higher irradiance under same temperature condition and it increased with increasing daylengths (8-16 h). Chaetomorpha linum grew in wide range of N and P concentrations. The growth of germling was maximal at $50{\mu}M\;{PO_4}^{3-}$ and $40{\mu}M\;{NH_4}^+$. Germling growth was more effective under nitrogen addition than phosphorus addition in culture. In conclusion, optimal environmental conditions for zoospore release were $20^{\circ}C$, $100{\mu}mol\;photons\;m^{-2}s^{-1}$, and 34 psu. In addition, the optimal germling growth was observed at $25^{\circ}C$, $100{\mu}mol\;photons\;m^{-2}s^{-1}$, 34 psu, 16 h, $50{\mu}M\;({PO_4}^{3-})$ and $40{\mu}M\;{(NH_4}^+)$.

• Horticultural Science & Technology
• /
• v.35 no.4
• /
• pp.439-445
• /
• 2017

Transplant production in a plant factory with artificial lighting provides several benefits; (1) rapid and uniform transplant production, (2) high production rate per unit area, and (3) production of disease free transplants production. To improve the growth of runner plants when strawberry transplants are produced in a plant factory, we conducted two experiments to investigate (1) the effect of different light intensity for stock and runner plants on the growth of runner plants, and (2) the effect of different container volume for runner plants on their growth. When the stock and runner plants were grown under nine different light conditions composed of three different light intensities (100, 200, and $400{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPF) for each stock and runner plants, increasing the light intensity for stock plants promoted the growth of runner plants, however, the growth of runner plants was not enhanced by increasing the light intensity for runner plants under same light intensity condition for stock plants. We also cultivated runner plants using plug trays with four different container volumes (21, 34, 73, and 150 mL) for 20 days after placing the stock plants, and found that using plug trays with lager container volume did not enhance the growth of runner plants. These results indicate that providing optimal condition for stock plants, rather than the runner plants, is more important for increasing the growth of the runner plants and that the efficiency of strawberry transplant production in a plant factory can be improved by decreasing light intensity or container volume for runner plants.

• Journal of Microbiology and Biotechnology
• /
• v.4 no.2
• /
• pp.126-133
• /
• 1994

A Pseudomonas putida strain able to accumulate high amount of polyesters of medium-chain-length 3-hydroxyalkanoic acids ($PHA_{MCL)$) was isolated from soil in a landfill site using an enrichment technique. Culture condition of the isolated strain for polyester production in a one-step culture was optimized in a mineral-salts medium against pH and concentrations of ammonium sulfate, carbon source(e.g., octanoate), and phosphate. The optimal values for maximal cell growth and PHA accumulation were: pH; 7$\sim$8, $(NH_4)_2SO_4$; 8 mM, octanoate; 40 mM. The optimum temperature was in the range of $20\sim30^{\circ}C$, which was rather broader than in other bacteria. Cell growth was strongly inhibited by the phosphate limitation to less than 1 mM. An increase of phosphate concentration above 1 mM showed little effect on cell growth and polyester accumulation. When the strain was grown on octanoate under this optimized condition it produced 3.4 g dry biomass per liter and yielded 1.7 g PHA per liter amounting to 53 wt% of dry cells. The monomer units composing the polyester synthesized from octanoate were 3-hydroxyoctanoate (3HO), 3-hydroxycaproate (3HC), and 3-hydroxybutyrate (3HB) (85:13:2, mole ratio). Other low linear $C_3\simC_{10}$ monocarboxylic acids were also tested for polyester production.

• Korean Journal of Medicinal Crop Science
• /
• v.10 no.4
• /
• pp.243-248
• /
• 2002

The effects of basal media, carbon, nitrogen, phosphate and some major macro elements on growth and shikonin production in Lithospermum erythrorhizon hairy root culture were studied. Among examined media, growth of hairy root cultured in B5 liquid medium was rapid, whereas shikonin production was high in MS liquid medium. Under B5 basal medium, sucrose concentration for optimal growth and shikonin production was 9% and 4% respectively. The growth and shikonin production on pH changes in B5 medium resulted little effect in pH 5.8 to pH 8.8 ranges, whereas growth was decreased dramatically in both above 8.8 and under 5.8. Nitrogen source and concentration effected on the growth and shikonin production. The highest growth rate was in B5 medium (50 mM $KNO_3$ and 1 mM $NaH_2PO_4)$, whereas the highest shikonin production was in the condition supplemented with 5 mM $KNO_3$ and 10 mM $NaH_2PO_4$.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.11
• /
• pp.3415-3423
• /
• 1996

The compact tension specimen geometry has been widely used for measuring fatigue crack growth rates at elevated temperature when the fatigue load is under tension/tension condition. However, most of the elevated temperature components which have significant crack growth life experience fatigue load under tension/compression conditions. Thus test techniques are required since the compact tension specimen cannot be used for tension/compression loading. In this paper, a simplified test procedure for measureing fatigue crack growth rates is proposed, which employs a round bar specimen with a small surface crack. Fatigue crack growth rates under tension/ tension loading conditions at elevated temperature were measured according to the proposed procedure and compared with those previously measured by C/(T) specimens. Since both the measured crack growth rates were comparable, the fatigue crack growth rates under tension/ compression load can be reliably measured by the proposed procedure. For monitoring crack depth. DC electric potential method is employed and an optimal probe location and current input conditions were proposed.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.337-337
• /
• 2017

Accurate and optimal water supply to cereal crop is critical in growing stalks and producing maximum yields. Excessive soil moisture may cause nutrient deficiencies and oxygen deficiency. Excessive soil water during crop growth stages results in decrease of yields. In Korea, the largest agricultural lands are paddy fields. Recently, upland crops are cultivated in paddy field soils to reduce overproduced rice in Korea. In order to success this policy, it is necessary to fully understand crop response to excessive soil moisture condition from paddy field soils. Adzuki bean is one of major legumes which provide protein in daily diet. Adzuki bean has been well know its weakness to excessive soil moisture condition, In order to obtain optimal yields of adzuki bean from paddy field cultivation, it is necessary to understand response of adzuki bean under different soil moisture conditions. This study investigated characteristics of growths, yields and response degree of water stress from adzuki bean. Three cultivars were selected for this study; Chungju, Hongeon, and Arari. All adzuki beans were cultivated in a paddy field which was divided into three sections with different soil moistures. The paddy field was located in Milyang, Gyeongsangnam during 2016. One section of the paddy field had the greatest average soil moisture content as 35.1% during adzuki bean cultivation (very poor). The second greatest soil moisture section had 32.6% (somewhat poor) and the smallest soil moisture section had 28.9% of soil moisture (somewhat well). During cultivation of three cultivar adzuki beans, soil moisture contents and groundwater levels were monitored. All the characteristics of growth and yield components were measured; height, thickness, 100 seed weights etc. Stress index values were calculated by Stress Day Index (SDI). All cultivars had the greatest yields from somewhat well section. Chungju had the greatest yields throughout all three sections compared to other cultivars. Chungju had 81% greater yield than Hongeon which had the smallest yield from somewhat well section. Arari set in middle from all sections. However there was no significant differences yields from very poor and somewhat poor sections. Leaf SPAD values tended to decrease and stable carbon isotope values increased as soil moisture increased. However, Chungju had no difference across different soil moistures in SPAD and stable carbon isotope values, while Hongeon had the greatest differences across sections. These trends followed by SDI values. Chungju had the smallest SDI values compared to other cultivars, which meant that Chungju was the strongest tolerance against excessive soil moisture than other cultivars. All three cultivars showed severe decrease of yields from very poor and somewhat poor sections. Arari and Hongeon showed great decrease from somewhat well section compared to yields from upland soil. These two cultivars may not be proper cultivating in paddy fields. In conclusion, adzuki bean is very sensitive to soil moisture condition and detailed soil managements are required to obtain optimal yields of adzuki bean from paddy field cultivation.

• Mycobiology
• /
• v.38 no.3
• /
• pp.195-202
• /
• 2010

Coriolus versicolor, is one of the most popular medicinal mushrooms due its various biologically active components. This study was conducted to obtain basic information regarding the mycelial culture conditions of C. versicolor. Based on the culture, and MCM media were suitable for the mycelial growth of the mushroom. The optimum carbon and nitrogen sources were dextrin and yeast extract, respectively, and the optimum C/N ratio was 10 to 2 when 2% glucose was used. Other minor components required for optimal growth included thiamine-HCl and biotin as vitamins, succinic acid, lactic acid and citric acid as organic acids, as well as $MgSO_4{\cdot}7H_2O$ as mineral salts.

• Korean Journal of Pharmacognosy
• /
• v.27 no.4
• /
• pp.301-308
• /
• 1996

Hairy roots induced from stems of Rubia cordifolia var. pratensis were cultured in the liquid medium under a variety of auxins to find the optimal condition for the growth and production of pigments. Culture of the hairy roots on NN liquid medium containing NAA 0.5 mg/l was best for growth of hairy roots. Production of yellow anthraquinone derivatives and purpurin in hairy roots was enhanced by the culture on NN liquid medium without auxins. Effects of L-phenylalanine, L-tyrosine and juglone, synthesized via the shikimic acid pathway, on growth and production of pigments in hairy roots were studied in the present study. Concentration of exogeneous L-phenylalanine. L-tyrosine and juglone in liquid culture system of hairy root containing NAA 0.1 mg/l was decreased quickly in its early stages of the culture period. Addition of juglone to NN liquid medium containing NAA 0.1 mg/l enhanced the productivity of pigments in hairy roots.

• Microbiology and Biotechnology Letters
• /
• v.26 no.4
• /
• pp.303-308
• /
• 1998

A bacterial strain which utilizes phenol under denitrifying condition was isolated from the industrial waste water collected from the Chong-ju Industrial Complex. The strain was identified as Pseudomonas species from the morphological, physiological, and biochemical characteristics and designated as HL100. The strain can utilize phenol as the sole source of carbon and energy when nitrate is provided as the terminal electron acceptor. The isolated strain completely degraded 3 mM of phenol within 110 hour with concomitant reduction of nitrate to nitrite. The observed maximum doubling time was 20 hours. Under appropriate condition, complete reduction of nitrate to atmospheric N$_2$ was observed indicating that the isolated strain could perform complete steps of denitrification. The strain showed optimal growth at pH 7.0 and temperature of 37$^{\circ}C$ under denitrifying phenol-degrading condition. The strain can also utilize toluene as the sole carbon and energy source under the same growth condition. However, no growth was detected on xylene and benzene.