• Applied Biological Chemistry
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• v.51 no.1
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• pp.1-5
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• 2008

Salt accumulation in soils of greenhouse due to the massive application of nitrogen fertilizers causes salt stress on the various crops, a serious problem in domestic agriculture. Since the majority of the salinity is nitrate, the excess nitrate should be removed; therefore, a bacterial strain having high capacity of nitrate uptake and identified as Enterobacter amnigenus GG0461 was isolated from the soils of greenhouse. Optimum conditions for the bacterial growth and nitrate uptake were investigated. GG0461 was able to grow without nitrate; however, nitrate facilitated the growth. The rate of nitrate uptake increased at alkaline pH and both growth and nitrate uptake were maximal at pH 8-9. When the initial pH of culture medium was increased to pH 8 or 9, it was decreased to neutral upon bacterial growth and nitrate uptake. These results imply that the major factor mediating bacterial nitrate uptake is a nitrate/proton antiporter. The fact was supported by the effect of nitrate addition in the absence of nitrate, since the addition of nitrate greatly increased the nitrate uptake and rapidly decreased pH of media.

• Journal of Applied Biological Chemistry
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• v.54 no.4
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• pp.252-257
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• 2011

To remove excess nitrate from the agricultural environments, Enterobacter amnigenus GG0461 has been isolated as a bacterial strain having high capability of nitrate uptake activity. This strain was able to remove nitrate more than 3,000 ppm (50 mM) in the Pseudomonas agar F (PAF) medium. Therefore, it could be a candidate strain for a nitrate scavenger in the various contaminated environments, such as agricultural soils, livestock sewage, and industrial wastewater. In order to develop medium for the large-scale production of the strain GG0461, each component of PAF medium was replaced with the corresponding commercial product and the optimal conditions for bacterial growth and nitrate uptake activity were measured. Glycerol was replaced with the commercially available product and the nitrogen source was substituted with commercial tryptone, yeast extract, soybean meal, and fermented fish extract. Bacterial growth and nitrate uptake activity were maximal in the media containing 2% tryptone, followed by yeast extract, soybean meal, and fermented fish extract. The pH of the growth medium containing 2% tryptone was decreased by the bacterial nitrate uptake, suggesting that the nitrate uptake is mediated by a nitrate/proton antiporter. This result shows that the medium containing commercial tryptone was good enough for the physiological activity of the strain GG0461. Each component of PAF medium was successfully replaced with the corresponding commercial product except peptone. In conclusion, the composition of medium for the cultivation of the strain GG0461 was determined as 2% tryptone, 1% glycerol, plus required salts according to the composition of PAF medium.

• Journal of Applied Biological Chemistry
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• v.54 no.2
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• pp.79-83
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• 2011

Over-application of nitrogen fertilizer keeps increasing the salinity in the soils of greenhouse in domestic agriculture. In order to remove the excess amounts of soil nitrate, soil microorganisms which have high capacity of nitrate uptake were isolated from the upland soils and their nitrate uptake activities were measured. Strain GS2 was able to remove 50 mM nitrate within 12 h. After sequence comparison analysis of 16S rRNA gene, the strain was identified and named as Bacillus sp. GS2. When the growth and nitrate uptake activities were measured, maximal values were obtained at $30-40^{\circ}C$ and $37^{\circ}C$, respectively; however, both were optimal at pH 6-8. In the media containing 50 mM nitrate, Bacillus sp. GS2 removed 43 mM nitrate which is corresponding to 86% removal. Similar amounts of nitrate removal were observed at the nitrate concentrations up to 300 mM, showing a saturation in nitrate uptake at concentrations above 50 mM. These results imply that Bacillus sp. GS2 can be a good candidate for the microbial remediation of accumulated environmental nitrate because of its excellent growth and nitrate uptake activity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.782-793
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• 1997

To study the physiological adaptation (shift-up) of phytoplankton under the simulated upwelling conditions, nitrate uptake capacity of Dunaliella tertiolecta batch culture was measured in the laboratory using the stable isotope $^{15}N-KNO_3$. Contrary to the expected, there was no significant relationship between the maximum $V_{NO3}$ (nitrogen specific nitrate uptake rate) and the initial nitrate concentration. However, there was a strong relationship between the maximum $\rho_{NO3}$ (nitrate transport rate) and the initial nitrate concentration of $<25\;{\mu}M$, which was also influenced by the physiological status of the culture. The increase in $V_{NO3}$ was mainly due to the increase in PON (particulate organic nitrogen) concentration and partly due to the increase in $V_{NO3}$. When the phytoplankton population was severely shifted-down, the physiological adaptation of nitrate uptake was significantly inhibited at high initial nitrate concentrations. The timing of the maximum $V_{NO3}$ or $\rho_{NO3}$ was related to the initial nitrate concentration. At higher initial nitrate concentrations, maxima in $V_{NO3}$ and $\rho_{NO3}$ occurred 1 or 2 days later than at lower nitrate concentrations. This relationship was the opposite to the prediction from the shift-up model of Zimmerman et al. (1987), The shift-up process is apparently controlled by an internal time sequence and the initial nitrate concentration, but the magnitude of $V_{NO3}$ was affected little by changes in nitrate concentration.

• Korean Journal of Environmental Agriculture
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• v.21 no.1
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• pp.69-73
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• 2002

Lettuce (Lactuca sativa L.) plants were grown under hydroponic system to characterize the diurnal change of nitrate concentration and nitrate uptake rate and to examine the effect of short term cold treatment to rhizosphere on nitrate concentration and uptake rate in lettuce plant. The nitrate concentrations in midrib were two times higher than those in leaf. Nitrate concentration in the shoot reached to minimum (8.7 mg-N/GDW) at 14:00 and, thereafter, increased continuously until 23:00. During 11:00$\sim$17:00, nitrate uptake by lettuce plant was maximum (4.8 mg-N/GDW-Root/hr). Short term cold treatment reduced nitrate concentration in the shoot by 14$\sim$18%, and nitrate uptake rate by 50$\sim$55%, respectively. These results showed that short term cold treatment before harvest could be applied for the purpose of reduction of nitrate concentration in the leaf under hydroponic culture.

• Journal of Applied Biological Chemistry
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• v.56 no.4
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• pp.241-244
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• 2013

Nitrate is one of the major nutrients in plants, and nitrate fertilizer often overused for the high yields of crops. Nitrate deposit in soil became one of the major reasons causing salt stress. Specially, salt stress is a serious problem in the soils of plastic film or glass houses. In this study, six microorganisms have been isolated from the wet soils near the disposals of livestock farms and their nitrate uptake activities were investigated. These bacteria were able to remove nitrate as high as 1,000-3,000 ppm (10-50 mM). The strain PCE3 showed the highest nitrate uptake activity and it removed more than 3,700 ppm. In order to identify these bacteria, genes of 16S rRNA were sequenced and analyzed. Phylogenetic trees were constructed with the neighbor-joining methods. Among these bacteria, strain PCE3 was identified as Bacillus species. When the growth and nitrate uptake activities were measured, both were maximal at $37^{\circ}C$ and optimal pH was pH 7-9. Bacillus sp. PCE3 removed nitrate up to 40-60 mM (2,500-3,700 ppm) depending on the nitrate concentration in media. Therefore, Bacillus sp. PCE3 can be a good candidate for the microbial remediation of nitrate-deposited soils in glass and plastic film houses.

• Journal of the Korean Society of Tobacco Science
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• v.7 no.2
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• pp.141-149
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• 1985

뿌리에서 흡수된 질소는 대부분이 질산태이온으로 잎의 엽맥까지 도달하나 엽육에서 급격히 환원되어 유기태질소로 동화한다. 잎의 주맥을 통과하여 세맥까지 질산태질소로 이동되며 전질소의 1/2이상의 양까지 다다르나 엽육에서는 전질소함량이 엽맥의 5배까지 증가되어도 질산태질소는 $10^{-2}$ 정도로 급격히 환원되었다. 칼륨은 엽맥까지 질소와 동반 이동하나 엽육에서의 질산태질소환원에 의하여 이동이 차단되는 현상을 보였다. 엽육에 축적된 칼륨은 능금산의 축전을 촉진하였고 질산환원효소의 활성이 왕성하게 일어나는 하위엽에 높은 농도로 축적되었다.

• Journal of The Korean Society of Grassland and Forage Science
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• v.20 no.3
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• pp.199-206
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• 2000

This experiment was conducted to evaluate the effect of winter forage rye and green manure hairy vetch on soil mineral nitrogen and corn nitrogen uptake. Soil nitrate at corn seeding decreased slightly with cultivation of winter rye, but soil nitrate did not decreased by cultivation of winter hairy vetch. Soil nitrate nitrogen increased 60~70 kgN/ha higher by hairy vetch green manure than winter rye and fallow at 6-leaf and harvest stage of corn, respectively, and much soil nitrate nitrogen such as 85, 125 kgN/ha was remained at N fertilizer 100, 200 kgN/ha of hairy vetch green manure at harvesting time, respectively. Corn yield was not different among treatments of winter crop and N rate, but nitrogen concentration of corn stover increased by hairy vetch green manure. Increase of total corn nitrogen uptake by hairy vetch green manure was 50~60 kgN/ha compared with winter rye and fallow. It is thought that basal fertilizer nitrogen 100 kgN/ha could be reduced by hairy vetch green manure in considering soil nitrate and nitrogen uptake at harvesting time.

• 비료회보
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• s.402
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• pp.28-49
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• 1991

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2007.05a
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• pp.383-389
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• 2007

호기시간 변경에 따른 SBR에서의 영양염류제거특성과 MLVSS의 변화를 본 이번 연구에서는 다음과 같은 결론을 얻었다. 1) 충분하지 못한 산소의 공급은 미생물의 wash-out으로 인한 영양염류 제거 효율의 저조를 나타냈다. 2) 산소 공급량이 $0.045m^3$였던 R2에서 저조산 질산화가 나타났으나, 인을 과다 축적하는 EBPR(Enhanced Biological Phosphorus Removal)을 나타냈다. 3) 산소 공급량이 $0.06m^3$이상이었던 R3, R4에서는 60%이상의 질산화 및 탈질화와 약 100%에 달하는 인 제거 효율을 나타내었다. 4) 단위 미생물당 $1.5{\sim}1.8ml/mg$의 공급 산소량이 인 흡수에 유리한 것으로 나타났다. 5) 공급되는 산소에 있어 유기물 분해>인흡수>질산화에 우선적으로 소모되는 것으로 나타났다.