• The Korean Journal of Ecology
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• 제18권1호
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• pp.43-54
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• 1995

Effects of environmental factors of N, P, pH, moisture, temperature and oxygen on growth and nitrogen fixation activity of kummerowia striate (Thunb.) Schindler seedling, bearing symbiotic root nodules, were quantitatively analyzed during the growing period. The specific nitrogenase activity (ARA) of nodules showed the maximum value of 187 μmol C₂H₄g fr wt-1 h-1 6 weeks after seeds were germinated. The total nitrogenase activities per plant attained as 1.56, 0.85, 0.09 and 4.0, 1.11, 0.04 μmol C₂H₄hr-1, respectively for the treatments of 1, 3 and 5 mM NO₃￣and NH₄＋ on the 60th day. While the plant grown in N-free media for 20 days after treatments of 5 mM NH₄+for 40 days resulted in 30 mg fr wt of nodule formation and exhibited the relative activities of 152％ and 162％ for total and specific ARA in comparison with those of control plant grown with N-free for 60 days. Total biomass and ARA was by 70％ and 86％ lower in N and P deficiency, respectively. The N and P deficient plot showed 70％ and 86％ decreases of total biomass and ARA in comparison with those of control. The plant grown with N-free for 20 days after pretreatment with N and P free media for 40 days showed the relative values of 77％, 118％ and 150％, respectively for nodule biomass, total and specific ARA in comparison with those of control. The treatment with acid or alkali gradients resulted in significant decreases of nodule biomass and ARA. The optimum temperature and pO₂for ARA were 30°C and 40 kPa, respectively. Two peaks of diurnal variation appeared at 11:00 and 23:00 o'clocks by the continuous light condition. The plants with water stress by temporary wilting point rsulted in 95~97％ inhibition for nodule respiration, transpiration and specific ARA. Transpiration and ARA ware recovered to 88％ and 38％ of those of water unstressed plants, respectively, 6 hours after the plants were rewatered from water stressed condition.

• KSBB Journal
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• 제6권4호
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• pp.413-424
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• 1991

Bitid"bactcria를 이용한 요구르트 제조를 위하여 B. bitidwη의 우유내에서 최시 배양조간과 B. bitidum. L. acidophilus 및 Str. thermophihilus의 혼합배양시의 최적 조건을 조사하고 요구르트 제조에 적합한 조건을 조사하여 다음과 같은 결과을 얻었다. B. bitidum의 성장을 위한 탈지유아 농도는,15% 농도가 12%농도보다 산진전은 잘 되었으나 균의 생존력에서 12% 농도가 적합한 것으보 나타났다. B. bifidum 의 성장에 대한 L-cysteine.HCl, yeast extract, glucose와 BIOS 2000의 성장촉진물 침가효과는 BIOS 2000을 첨가한 것이 산 진전면과 균수 유지면에서 B. bhifidum익 성장에 큰 효과가 있었다. B. bifidum, L.acidophilus와 Str. thermophilus를 혼합하여 배양한 것이 산 진전과 균수면에서 B. bifidum 단독 배양한 것보다 좋게 나타났다. B. bifidum. L. acidophilus 와 SIr. thermophilus의 세 균주 혼합배양액을 이용한 요구르트 제조시 접송량은 5%. 배양온도는 $37^{\circ}C$와 배양시간은 8시간이 석당하였다 . 이 경우 세 균주의 비율은 B. bifidu: L. acidophilus. Str. thermophilus가 2:1:1의 비율이 균수유지와 산 진전면에서 가상 좋은 결과를 보였다.

• 한국식품과학회지
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• 제18권3호
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• pp.210-214
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• 1986

수소세균을 단세포단백질자원으로 이용하기 위한 기초연구로서 수소를 에너지원으로 이산화탄소를 탄소원으로 하는 autotrophic condition에서 수소세균 Alcaligenes eutrophus ATCC 17697의 배양조건 및 균체성분을 조사하였다. 균체성장을 위한 최적 pH와 온도는 각각 7.0과 $30^{\circ}C$ 이었으며 0.059atm부터 0.27atm까지의 산소분압범위에서 균체성장에 대한 산소분압의 영향을 본 결과 산소분압 0.11atm$(H_2:O_2:CO_2=7\;:\;1\;:\;1)$에서 최대비증식속도 ${\mu}max\;=0.31hr^{-1}$를 보였다. 건조균체의 조단백, 핵산, 회분함량은 각각 69.2%, 17.6%, 3.62%이었다.

• 아시안잔디학회지
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• 제15권1호
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• pp.15-20
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• 2001

Two types of annual bluegrass have been reported, and those consist of annual type (Poa annua ssp. annua) and perennial type (Poa annua ssp. reptans). As a weed, annual bluegrasses are commonly found in putting greens and fairways in many golf courses. Due to its strong competitiveness such as tremendous seed reproduction rate a year, prostrate growth habit, and no herbicide availability, annual bluegrasses have been considered as one of the most hard-to-control weeds in turf management systems. A growth chamber study was conducted to determine seed dormancy and to understand seed germination characteristics of annual bluegrass (Poa annua ssp. annua). Freshly harvested seeds showed 80 and 55% germination at 30 and $35^{\circ}C$, respectively, indicating that the optimum temperature of annual bluegrass is $30^{\circ}C$. However, the seed germination occurred only under light condition at any given temperature. This result demonstrated that light is prerequisite for the seed germination, and no primary dormancy of annual bluegrass seed exists. Secondary seed dormancy induced by unfavorable temperatures and dark condition was broken through 4 to 6 wk-storage at $4^{\circ}C$ with moisture, and the stored seeds germinated at $20^{\circ}C$ even under the dark. In red and far-red light trial, fresh seeds resulted in 40% germination under red while no seed germination occurred under far-red light condition, indicating that phytochrome Pr and Pfr could be related to annual bluegrass seed germination. When the far-red light replaced the red the germination was recovered, but this reversibility did not reach to the germination level under the red light only. This result implied that other lights than red and far-red would play an important role on seed germination of annual bluegrass.

• 한국수산과학회지
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• 제16권1호
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• pp.37-43
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• 1983

식중독 원인균으로 알려져 있는 Bacillus cereus 균의 포자를 cooked rice homogenate 배지에 접종하여 pH, 식염과 솔빈산 칼륨의 농도를 변화시키면서 배양할 때 포자의 발아에 미치는 영향을 실험한 결과를 요약하면 다음과 같다. 1. 포자의 발아범위는 pH $4.5{\sim}10.0$이었으며 발육최적 pH는 7.0 부근으로 $32^{\circ}C$에서 배양 5시간만에 $10^7/ml$에 도달하였다. 2. 식염농도 $2\%$일 때 포자의 발아는 가장 활발하였고, $5\%$ 이상에서는 농도와 비례하여 감소되었다. 이에 반하여 포자형성율은 $2\%$에서 제일 낮았고 $10\%$에서 가장 높은 값을 나타내었다. 3. 솔빈산 칼륨의 농도가 증가될수록 포자의 발아율은 감소하였고 포자형성율은 약간 증가하였다.

• 생명과학회지
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• 제13권5호
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• pp.705-711
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• 2003

Pseudomonas elodea ATCC 31461에 의해 생산되는 미생물 다당류인 gellan의 최적 조건을 확립하기 위해 flask상에서 inoculum size, 탄소원 종류 및 농도, 질소원 종류, C/N ratio등을 조사하였다. Gellan 생산을 위한 최적 inoculum size는 5%(v/v)로 나타났으며, 1.0%(w/v)의 glucose에서 2.22의 최대 specific yield 와 $0.03 g/\ell$의 생산성을 얻을 수 있었다. 또한 ammonium nitrate가 없을 때 최대 생산을 얻을 수 있어, gellan 생산을 위해서 nitrogen limitation이 필요함을 알 수 있었다 Glucose와 bactopeptone을 이용하여 C/N ratio를 조사한 결과 20에서 gellan 생산이 가장 높게 나왔다.

• Journal of the Korean Wood Science and Technology
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• 제48권4호
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• pp.548-561
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• 2020

Paecilomyces japonica is widely cultured to produce mycelium for medicinal and health food use. Illumination is an important factor in the growth and production of mycelium in submerged culture. The effects of different light-emitting diode (LED) combinations on the growth and cordycepin content as bioactive substances of mycelium were investigated. The results showed that the mycelium dry weights were lower under dark condition and red LED treatments. Dark condition, fluorescent light, and ultraviolet-A failed to increase the cordycepin content. Blue light was necessary to increase the cordycepin content, and a red-to-blue ratio of 3:7 induced the highest cordycepin content. The cordycepin contents of mycelium in submerged culture were significantly higher in a 12 h/day illumination time under red and blue (red-to-blue ratio of 3:7) LED treatments, showing an increase of up to 38% compared with those under the fluorescent-light control condition. The results demonstrated the roles of light with different wavelengths on the biosynthesis of cordycepin as bioactive substances. The low-heat release and replacement of traditional fluorescent lights with low-energy-consuming LEDs could increase the contents of bioactive substances. After optimization of the cordycepin production using response surface methodology (Box-Behnken design) to its canonical form, the optimum combination was found to be as follows: illumination time = 17.7 h/day, sugar content in the medium = 9.7 g/50 mL, and incubation time = 61.2 h. The model predicted a maximum response of 3779.2 ㎍/mL cordycepin yield.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.26-26
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• 2009

Vertically aligned arrays of mm-long multi-walled carbon nanotubes (MWCNTs) on Si substrates have been synthesized by water-assisted thermal chemical vapor deposition (CVD). The growth of CNTs was investigated by changing the experimental parameters such as growth temperature, growth time, gas composition, annealing time, catalyst thickness, and Al underlayer thickness. The 0.5-nm-thick Fe served as catalyst, underneath which Al was coated as a catalyst support as well as a diffusion barrier on the Si substrate. We grew CNTs by adding a little amount of water vapor to enhance the activity and the lifetime of the catalyst. Al was very good at producing the nm-size catalyst particles by preventing "Ostwald ripening". The Al underlayer was varied over the range of 15~40 nm in thickness. The optimum conditions for the synthesis parameters were as follows: pressure of 95 torr, growth temperature of $815^{\circ}C$, growth for 30 min, 60 sccm Ar + 60 sccm $H_2$ + 20 sccm $C_2H_2$. The water vapor also had a great effect on the growth of CNTs. CNTs grew 5.03 mm long for 30 min with the water vapor added while CNTs were 1.73 mm long without water vapor at the same condition. As-grown CNTs were characterized by using scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and Raman spectroscopy. High-resolution transmission electron microscopy showed that the as-grown CNTs were of ~3 graphitic walls and ~6.6 nm in diameter.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1989년도 춘계학술대회 논문집
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• pp.43-46
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• 1989

Epoxy, noticed as a new insulation material for electrical equipments, may become an excellent cured material from the crosslink reaction with some curing agents and accelerators. The characteristics of cured epoxy is determined by the method of lattice formation according to curing method. The purpose of this paper, varing the process of lattice formation by various surrounding temperatures and heating time during the curing process, is to obtain the optimum cured condition for electrical insulation from the results of investigation on the physical and dielectric properties of cured epoxy. In this investigation, it is found that the excessive temperature and heating time brings on the growth of metamorphic methyl and the insulating properties of cured epoxy is decreased by this phenomenon. As a result, it is concluded that the optimum dielectric characteristics can be obtained when cured at a curing temperature at 14$0^{\circ}C$ for one hour.

• 한국식품과학회지
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• 제21권3호
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• pp.399-403
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• 1989

A. cylindracea의 균사 성장을 위한 영양배지 조성 및 배양조건을 최적화하였다. 최적 영양배지 조성은 starch 20.0g/l, bacto-soytone 4.0g/l, 그리고 yeast extract 6.0g/l였다. 무기염류 $KH_2PO_4\;0.46g/l,\;K_2HPO_4\;1.0g/l,\;MgSO_47H_2O\;0.5g/l$을 첨가한 배지의 pH는 5.8로_ 완충되었으며 무기염류를 첨가하지 않은 배지보다 균사성장이 양호하였다. 균사의 최적 배양온도는 $28^{\circ}C$였으며 최적 생장 pH는 6.0이었다. 균사 성장 온도범위는 $10-35^{\circ}C$로서 $40^{\circ}C$ 이상에서는 균사가 사멸하였다.