• Environmental Engineering Research
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• 제11권4호
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• pp.173-180
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• 2006

Autotrophic nitrogen removal and its microbial community from a laboratory scale upflow anaerobic sludge bed reactor were characterized with dynamic behavior of nitrogen removal and sequencing result of molecular technique (DNA extraction, PCR and amplification of 16S rDNA), respectively. In the experiment treating inorganic wastewater, the anaerobic granular sludge from a full-scale UASB reactor treating industrial wastewater was inoculated as seed biomass. The operating results revealed that an addition of hydroxylamine would result in lithoautotrophic ammonium oxidation to nitrite/nitrate, and also hydrazine would play an important role for the success of sustainable nitrogen removal process. Total N and ammonium removal of 48% and 92% was observed, corresponding to nitrogen conversion of 0.023 g N/L-d. The reddish brown-colored granular sludge with a diameter of $1{\sim}2\;mm$ was observed at the lower part of sludge bed. The microbial characterization suggests that an anoxic ammonium oxidizer and an anoxic denitrifying autotrophic nitrifier contribute mainly to the nitrogen removal in the reactor. The results revealed the feasibility on development of high performance lithoautotrophic nitrogen removal process with its microbial granulation.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.665-670
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• 2003

우라늄 변환시설 내의 lagoon 슬러지의 처리 공정에서 발생하는 고농도 질산염 폐액의 처리를 위해 질산염 폐액의 열역학 및 열분해 특성을 조사하였다. 열역학적 특성은 고농도 질산염 폐액의 조성을 바탕으로 COACH와 GEMINKI II를 사용하여 조사하였으며, 열분해 특성은 TG/DTA, XRD 분석을 통하여 실제 질산염 폐액에 대하여 조사하였다. 폐액 내 함유 성분 중 $NH_4NO_3$는 $^250{\circ}C$에서 모두 분해되었으며, 잔류물의 대부분을 차지하는 $NaNO_3$는 $730^{\circ}C$에서 분해되는 것으로 나타났다. $NaNO_3$의 분해생성물인 불안정한 $Na_2O$를 안정한 화합물로 변화시켜 주기 위하여 $Al_2O_3$를 첨가할 경우 $NaNO_3$는 $450^{\circ}C$의 낮은 온도에서 분해 가능하였다. 이 같은 열역학 및 열분해 특성을 바탕으로 고농도 질산염 폐액의 처리 공정도를 제시하였으며, 특성 자료는 공정 모사의 기초 자료로 활용될 것이다.

• Journal of Ginseng Research
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• 제47권3호
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• pp.469-478
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• 2023

Background: Nitrogen (N) is an essential macronutrient for plant growth and development. To support agricultural production and enhance crop yield, two major N sources, nitrate and ammonium, are applied as fertilizers to the soil. Although many studies have been conducted on N uptake and signal transduction, the molecular genetic mechanisms of N-mediated physiological roles, such as the secondary growth of storage roots, remain largely unknown. Methods: One-year-old P. ginseng seedlings treated with KNO₃ were analyzed for the secondary growth of storage roots. The histological paraffin sections were subjected to bright and polarized light microscopic analysis. Genome-wide RNA-seq and network analysis were carried out to dissect the molecular mechanism of nitrate-mediated promotion of ginseng storage root thickening. Results: Here, we report the positive effects of nitrate on storage root secondary growth in Panax ginseng. Exogenous nitrate supply to ginseng seedlings significantly increased the root secondary growth. Histological analysis indicated that the enhancement of root secondary growth could be attributed to the increase in cambium stem cell activity and the subsequent differentiation of cambium-derived storage parenchymal cells. RNA-seq and gene set enrichment analysis (GSEA) revealed that the formation of a transcriptional network comprising auxin, brassinosteroid (BR)-, ethylene-, and jasmonic acid (JA)-related genes mainly contributed to the secondary growth of ginseng storage roots. In addition, increased proliferation of cambium stem cells by a N-rich source inhibited the accumulation of starch granules in storage parenchymal cells. Conclusion: Thus, through the integration of bioinformatic and histological tissue analyses, we demonstrate that nitrate assimilation and signaling pathways are integrated into key biological processes that promote the secondary growth of P. ginseng storage roots.

• 한국환경과학회지
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• 제11권6호
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• pp.519-528
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• 2002

This study was to evaluate the impact of river runoff and salt intrusion by tide on nutrient balance of estuary during a complete tidal cycle. 24 hours time series survey was carried out during a spring tide July 2001 on a tidal estuary in the Keum river. Three stations(A,B,C) were set along a transect line of about 10km, which linked the lower part of estuary dyke to the subtidal zone. Surface water was sampled simultaneously at each station every hours f3r the determination of nutrients. Water temperature, pH and dissolved oxygen were measured in situ. Riverine input of silicate and nitrate during ebb tide significantly increased the concentration of all stations. Conversely, during high tide, nutrient concentration were lowered by the mixing of fresh water with sea water Ammonium nitrogen concentration were higher at intertidal zone(Stn.B) due to sewage inflow to Kyeongpo stream and ammonium release under anaerobic conditions. Also, these results was discussed as a biological component that influences the processes of nutrient regeneration within the estuary. Best correlations were found at lower part of estuary dyke(Stn.A) for salinity against DIN(Y=0.121 Sal.+4.97, r2=0.956) and silicate(Y=0.040 Sal.+2.62, r2=0.785). But no significant correlation was found between salinity and ammonium. Unbalanced elemental ratio(N/P, Si/N and Si/P) depended significantly on the import of nutrients (silicate & nitrate nitrogen) from river and stream. The effect of the tidal cycle and river runoff is important that in determining the extend of the variations in nutrient concentrations at all station.

• 한국수산과학회지
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• 제46권4호
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• pp.424-436
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• 2013

Organic enrichment was investigated in surface sediments from the Yeoja and Gangjin Bays of Korea, which contain dense shellfish farms, in order to evaluate the contamination status and temporal changes in shellfish farming along these coasts. The degree of organic enrichment was determined using geochemical indicators (chemical oxygen demand, ignition loss, acid volatile sulfide, total organic carbon in sediments, and total nitrogen in sediments, ammonium and nitrate in pore water, and bioluminescence inhabitation for sediments). Temporal changes in organic enrichment conditions were detected by comparing our 2012 data to those previously reported from a survey conducted in 1999/2000. Organic enrichment was significantly higher in September than in May and July, in Gangjin Bay than in Yeoja Bay, and significantly higher in shellfish farms than in reference sites not used to culture shellfish. Ammonium concentrations in pore water were two orders of magnitude greater than nitrate concentrations, suggesting that these bays represent nitrogen-reducing environments.

• 한국미생물·생명공학회지
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• 제15권6호
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• pp.369-374
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• 1987

하상 오니 및 토양으로부터 D-$\alpha$-Amino-$\varepsilon$-Caprolactam(DAC)의 자화능이 우수한 균을 분리하여 Alcaligenes eutrophus로 동정하였다. Alcaligenes eutrophus A52의 생육을 위한 배양조건은 배양 초기 최적 pH가 6.0, 최적온도는 3$0^{\circ}C$, 최적 DAC 농도는 0.2%로서 50시간 배양으로 0.2% DAC를 거의 다 자화하여 정지기에 도달하였다. 본 균은 탄소원으로 glucose와 fructose, 질소원으로는 NH$_4$Cl, NH$_4$NO$_3$, (NH$_4$)$_2$SO$_4$ 및 NaNO$_3$를 잘 자화하였다. 탄소원 및 질소원으로 Iysine, glutamate를 잘 이용하였으나 그 밖의 아미노산 자화능은 낮았다. 균체로부터 추출한 3.1mg의 단백질에 상당하는 무세포 추출 액으로 0.5% DAC를 55%에서 12시간 반응시킨 생성물은 약 98% L-Iysine으로 확인되었다.

• 한국토양비료학회지
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• 제10권2호
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• pp.85-92
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• 1977

인산감수성(燐酸感受性)이 다른 9개대두재배종(個大豆栽培種) Lee, Hill, Harosoy, Clark-63, Chippewa 및 R56-49을 서로 다른 질소원(窒素源)으로 수경재배(水耕栽培)하여 엽중유리당(葉中遊離糖)과 유기산(有機酸)을 gas chronatograph로 조사(調査)하여 미동정(未同定)의 X, Y peak와 Sucrose peak가 주(主) peak로 나타났다. X 화합물(化合物)은 NO3-N 급여(給與)경우 흔적으로 나타난데 반하여 NH4-N나 urea 급여(給與)경우에 다량(多量)나타났다. Y 화합물(化合物)을 Urea 급여(給與)경우 감소하는 경향이었다. Sucrose는 NH4-N 급여(給與)에서 흔적으로 나타나고 Urea에서 NO3-N에서보다 높았다. X 화합물(化合物)은 erythrose에서 유래(由來)한 4 탄소(炭素) 산성당(酸性糖)이거나 Purine이나 Pyrimidine에서 유래(由來)한 환상화합물(環狀化合物)로 Y 화합물(化合物)은 glycolysis path에서 유래(由來)한 6 탄당(炭糖)으로 추정(推定)되었다. Y/X 치(値)는 인산감수성(燐酸感受性)의 좋은 지표(指標)가 되므로(역관계(逆關係)) 이 두 화합물(化合物)은 ammonia 독작용(毒作用) 및 인산감수성(燐酸感受性) 기작(機作)에 관여(關與)하는 요인화합물(要因化合物)로 보였다.

• 한국미생물·생명공학회지
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• 제47권1호
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• pp.11-19
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• 2019

The properties of microalgae as bioresources for biodiesel production can be improved by adding nitrogen sources into the culture medium. Thus, Nannochloropsis oceanica CCAP 849/10 was cultured in f/2 media supplemented with five different forms of nitrogen at $0.88mmol-N\;l^{-1}$ each: ammonium bicarbonate ($NH_4HCO_3$), ammonium sulfate ($(NH_4)_2SO_4$), sodium nitrate ($NaNO_3$), ammonium nitrate ($NH_4NO_3$), and urea. The cell density, lipid content, and fatty acid profile of the microalga were determined after 15 days of cultivation. The growth of N. oceanica based on cell number was lowest in the medium with $NH_4NO_3$, and increased significantly in the medium with $NH_4HCO_3$. Cells treated with $(NH_4)_2SO_4$, and $NH_4NO_3$ produced the highest total lipid contents (i.e., 65% and 62% by dry weight, respectively). The fatty acid profiles of the microalga were significantly different in the various nitrogen sources. The major fatty acids detected in cultures supplemented with $NH_4HCO_3$, $(NH_4)_2SO_4$, $NH_4NO_3$, or urea were C14:0, C16:0, C16:1, C18:0, C18:1, C18:2, C20:5, and C22:6. However, the C16:1 content in the $NaNO_3$-supplemented culture was very low. This study highlights that the nitrogen source can strongly influence lipid production in N. oceanica and its fatty acid composition.

• 한국해양학회지:바다
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• 제7권2호
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• pp.60-67
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• 2002

황해 대륙붕 해역의 전 수주(whole water column)의 질소 섭취율 중 무광대(aphotic zone)내 식물플랑크톤에 의한 질소 섭취율의 기여도를 파악하기 위하여 상부의 유광대(euphotic zone)와 하부의 무광대에서 식물플랑크톤에 의한 질소 섭취율의 크기를 측정하였다. 1997년 5월과 11월에 유광대와 무광대에서 일정량의 해수를 채취하여 선상에서 식물플랑크톤의 질산염과 암모늄 섭취율 측정을 $^{15}N$으로 표지하여 추적하였다. 전 유광대내의 질산염 및 암모늄 섭취율은 각각 1.8${\sim}$15.3 mg N $m^{-2}$ $d^{-1}$과 5.0${\sim}$132.2 mg N $m^{-2}$ $d^{-1}$의 범위이며, 대체로 암모늄 섭취율이 질산염 섭취율보다 우세하였다(1.9${\sim}$19.4배). 전 수주내의 질산염 및 암모늄 섭취율은 각각 2.9${\sim}$22.0 mg N$m^{-2}$ $d^{-1}$과 15.7${\sim}$175.5 mg N$m^{-2}$ $d^{-1}$의 범위를 나타냈다. 전 수주내의 총 질소 섭취율 중 무광대의 식물플랑크톤에 의한 질소 섭취율이 차지하는 비율은 질산염의 경우에 13.0${\sim}$86.2%, 암모늄의 경우에는 13.8${\sim}$67.8%로서, 무광대에서 식물플랑크톤에 의한 질소 섭취가 상당함이 발견되었다. 본 연구의 결과는 무광대내에서 상당한 양으로 활발하게 질소를 섭취하는 식물플랑크톤이 물리적 작용들(예를 들면, 와류 혼합, 수온약층의 수직이동 등)에 의해 유광대로 다시 편입(entrainment)될 경우 유광대의 물질 순환에 크게 기여할 가능성이 있음을 시사한다. 그리고, 본 연구 결과는 황해에서 신생산(new production)의 크기가 질산염 섭취로만 추정될 경우 과소평가될 가능성이 있으며, 암모늄 섭취에 기초한 재생산(regenerated production)의 일부가 신생산에 포함되어야 함을 제시한다.

• 생물환경조절학회지
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• 제15권1호
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• pp.84-90
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• 2006

This study was conducted to anticipate nitrate reduction state in tree through measurement of nitrate reductase activity (NRA) and investigate the effect of nitrogen concentrations (100, 200, 400, and 600 $mg\;L^{-1}$) on growth, the nitrogen content of various tissue, and NRA of pear (Pyrus pyrifolia cv. Niitaka) seedlings in sand culture. Nutrient solutions used in this experiment were adjusted to pH 6.5 and fixed the ratio of ammonium and nitrate to 1:3 and trickle-irrigated 3 times a day. Tree height and dry weight of various organs in seedlings were higher in low nitrogen concentration (100 and 200 $mg\;L^{-1}$) than in high nitrogen concentration (400 and 600 $mg\;L^{-1}$). The shoot growth in 600 $mg\;L^{-1}$ was extremely poor by nitrogen over supply. Increasing the nitrogen concentration, the concentration of nitrate-N in leaves and roots were insignificantly changed but that of stems increased. The accumulation of total and reduced nitrogen in all organs with increasing concentrations of nitrogen supply were increased at 30 days after treatment but those of all organs at 60 and 90 days after treatment were highest in 600 $mg\;L^{-1}$, whereas there were no significant changes among other nitrogen concentration. The in vivo (${+NO_3}^-$) NRA of all organs did not relate to nitrogen concentration but the in vivo (${-NO_3}^-$) NRA of leaves except roots increased with increasing the nitrogen concentration. Therefore, the proper nitrogen concentration to promote growth and nitrate reduction of pear tree was 200 $mg\;L^{-1}$.