• 환경생물
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• 제37권4호
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• pp.618-624
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• 2019

This study aimed to determine the growth and carbon storage of planted Haloxylon aphyllum in the Aralkum Desert in Kazakhstan. Six sites afforested in 2000, 2005, 2009, 2010, 2013, and 2017 were selected. The root collar diameter(cm) and height(m) were measured for all H. aphyllum in 30 m×44 m plots. Biomass accumulation (g m^-2) and carbon storage(C g m^-2) were calculated using allometric equations and the carbon concentration data of Haloxylon species. The diameters varied from 2.5 cm to 4.3 cm and the height varied from 106.2 cm to 223.7 cm. The growth of H. aphyllum was not linearly related to the afforestation year or soil properties. Tree growth might have been influenced by variations in the microclimate, such as temperature, precipitation, and dust storms. The mean total biomass accumulation was 20.57g m^-2 and ranged from 2.42 g m^-2 to 64.53 g m^-2. The mean carbon storage was 9.70C g m^-2 and ranged from 1.12 C g m^-2 to 30.61 C g m^-2. These biomass and carbon storage estimates were smaller than those reported for other Central Asian deserts, but afforestation enabled the generation of vegetative cover and consequently, carbon sequestration in the manmade Aralkum Desert.

• 한국환경과학회지
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• 제11권8호
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• pp.773-781
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• 2002

The natural carbon cycle has been perturbed since the mid-19th century by anthropogenic CO$_2$emissions from fossil fuel combustion and deforestation due to population growth and industrialization. The current study simulated the global carbon cycle for the past 42 years using an eight-box carbon cycle model. The results showed that since the terrestrial biospheric carbon sink was roughly offset by the deforestation source, the fossil fuel emission source was partitioned between the atmospheric and oceanic sinks. However, the partitioning ratio between the atmosphere and the ocean exhibited a change, that is, the carbon accumulation rate was faster in the atmosphere than in the ocean, due to a decrease in the so-called ocean buffering capacity. It was found that the ocean buffering capacity to take up excess CO$_2$decreased by 50% in terms of the buffer factor over the past 42 years. Accordingly, these results indicate that if the current CO$_2$emission trend continues, the future rate of increase in the atmospheric CO$_2$concentration will accelerate.

• 한국환경과학회지
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• 제19권12호
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• pp.1335-1341
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• 2010

Voltammetric diagnostics of pesticide thiram was studied in plant leafs in vivo fluid with DNA immobilized on a carbon nanotube electrode (DCE). Sensor properties of carbon nanotube (CE) and DNA immobilized nanotube were compared. DCE was more effective than CE in target detecting. The parameters such as pH strength, stripping accumulation, amplitude, and increment potential were examined to find the optimum condition for detection of pesticide thiram in a sesame leaf. The optimized conditions were as follows 550 Hz frequency, 0.15 V amplitude, 0.005 V increment potential, -1.2 V initial potential, 4.78 pH, 500 sec accumulation time. Under optimum condition, the detection limit of thiram was attained at 0.01ng/L.

• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.543-546
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• 2007

Herein, a new electrochemical method was described for the determination of ciprofloxacin based on the enhancement effect of an anionic surfactant: sodium dodecyl benzene sulfonate (SDBS). In pH 4.0 phosphate buffer and in the presence of 1.0 × 10-4 mol/L SDBS, ciprofloxacin yields a well-defined and sensitive oxidation peak at the carbon paste electrode (CPE). Compared with that in the absence of SDBS, the oxidation peak current of ciprofloxacin remarkably increases in the presence of SDBS. The experimental parameters, such as supporting electrolyte, concentration of SDBS, and accumulation time, were optimized for ciprofloxacin determination. The oxidation peak current is proportional to the concentration of ciprofloxacin over the range from 8.0 × 10-8 to 5.0 × 10-6 mol L-1. The detection limit is 2.0 × 10-8 mol L-1 after 2 min of accumulation. This new voltammetric method was successfully used to detect ciprofloxacin in drugs.

• 한국물환경학회지
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• 제22권1호
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• pp.134-139
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• 2006

Partial nitirification and denitrification process has been reported to be technically feasible and economically favorable, especially for wastewater treatment with high ammonium concentration or low Carbon/Nitrogen ratio. This research was performed to survey nitrite accumulation by nitritation in treating ADEPT effluent of piggery wastewater, which contains highly concentrated ammonia. To estimate the possibility of nitrite accumulation, DO concentration and SRT were investigated as key operational parameters. This result proved that nitritation to nitrite was steadily obtained under short sludge retention time. Oxygen limitation was proved to be just a subsidiary parameter. Energy efficiency of nitritation-denitritation process was higher than complete nitrification-denitrification because external carbon requirement for denitritation could be saved. Though the influent contained significant nonbiodegradable organic substrate, total nitrogen removal efficiency was more than 51% in nitritation-denitritation system.

• Journal of Microbiology and Biotechnology
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• 제1권1호
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• pp.75-78
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• 1991

The carotenoid biosynthesis of a red oleaginous yeast, Rhodotorula glutinis was significantly changed when the yeast was grown on different carbon substrates. The highest carotenoid production was obtained on culture medium containing glucose when the carbon to nitrogen ratio (C/N ratio) was adjusted to 25.7. Galactose stimulated the biosynthetic rate of torularhodin, a xanthophyll component of the yeast. With decreasing C/N ratio of the medium, significant changes of $\gamma$-carotene and torularhodin were observed such that increase in the torularhodin concentration was nearly equal to the decrease in $\gamma$-carotene. It was speculated that the nature of carbon substrate affected the metabolic rate of the cell, and accompanied by the different pattern of carotenoid accumulation in the cell.

• Journal of Forest and Environmental Science
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• 제15권1호
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• pp.71-76
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• 1999

본 연구는 춘천시의 도심지와 자연지 토양을 표본추출하여 그것의 물리화학적 특성과 탄소저장량을 비교 분석하였다. 토양산도는 도심지에서 평균 6.6, 자연지에서는 그보다 낮은 5.0이었고, 따라서 치환성양이온도 자연지에서 약간 더 낮았다. 유기물함량과 양이온치환능은 자연지에서 도심지보다 각각 1.4배, 1.7배 높은 반면, 유효태인산은 도심지에서 약 3.2배 높았다. 유기탄소저장량은 도심지 평균 $24.8{\pm}1.6$(표준오차) t/ha, 자연지 $31.6{\pm}1.6t/ha$로서, 자연지가 도심지보다 약 1.3배 더 많았다. 수목의 낙엽, 낙지 및 낙근에 의한 연간 탄소유입량에서 분해에 의한 연간 탄소유출량을 제감한 자연지 토양내 단위면적당 연간 탄소축적량은 1.3 t/ha/yr이었다. 춘천시 토양에 저장된 총탄소량은 연간탄소배출량 (245,590 t/yr)의 약 31%에 해당하였다.

• 자원ㆍ환경경제연구
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• 제30권2호
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• pp.347-364
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• 2021

국내의 탄소중립 정책은 다분히 온실가스 감축정책 위주로 구성되어 있는 것에 반해 미국, 영국, 중국 등 탄소중립을 선언한 국가는 경제성장과 기후변화를 동시에 달성하겠다는 목표를 갖고 있다. 본 논문은 온실가스 배출의 넷제로를 의미하는 탄소중립 개념을 램지의 경제성장 모형에 포함함으로써 탄소중립 정책이 자본축적의 장기적 동태적 과정에 미치는 효과를 분석하였다. 아울러 지속가능한 경제성장을 달성하기 위한 이른바 하트윅 규칙을 내포하였다. 넷제로의 탄소중립이 자본과 소비 경로의 정상상태와 더불어 나타날 때의 정상상태 균형을 분석하였다. 분석 결과를 보면, 램지 모형에 탄소중립과 하트윅 규칙을 포함할 경우 자본의 축적이 저규모 수준에서 정상상태에 도달하는 것으로 나타났다. 또한 재생에너지 확대가 다수의 이해집단에 의해 지대추구 대상이 될 때에는 자본축적 규모가 보다 더 악화될 수 있기 때문에, 에너지 전환과정에 공정한 시장제도 설계가 중요함을 알 수 있다.

• Journal of Microbiology and Biotechnology
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• 제4권2호
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• pp.146-150
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• 1994

Production of poly-$\beta$-hydroxybutyrate (PHB) in fed-batch fermentation was studied. Utilization of carbon for PHB biosynthesis was investigated by using feeding solutions with different ratios of carbon to nitrogen (C/N). It was observed that at a high C/N ratio carbon source was more preferably utilized for PHB accumulation while its consumption for cellular metabolism appeared to be more favored at a low C/N value. A high cell concentration (184 g/l) was achieved when ammonium hydroxide solution was fed to control the pH, which was also utilized as the sole nitrogen source. For the mass production of PHB, two-stage fed-batch operations were carried out where PHB accumulation was observed to be stimulated by switching the ammonium feeding mode to the nitrogen limiting condition. A large amount of PHB (108 g/l) was obtained with cellular content of 80% within 50 hrs of operation.

• Journal of Microbiology and Biotechnology
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• 제24권1호
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• pp.59-69
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• 2014

One of the major challenges in metabolic engineering for enhanced synthesis of value-added chemicals is to design and develop new strains that can be translated into well-controlled fermentation processes using bioreactors. The aim of this study was to assess the influence of various fed-batch strategies in the performance of metabolically engineered Pseudomonas putida strains, ${\Delta}gcd$ and ${\Delta}gcd-pgl$, for improving production of medium-chain-length polyhydroxyalkanoates (mcl-PHAs) using glucose as the only carbon source. First we developed a fed-batch process that comprised an initial phase of biomass accumulation based on an exponential feeding carbon-limited strategy. For the mcl-PHA accumulation stage, three induction techniques were tested under nitrogen limitation. The substrate-pulse feeding was more efficient than the constant-feeding approach to promote the accumulation of the desirable product. Nonetheless, the most efficient approach for maximum PHA synthesis was the application of a dissolved-oxygen-stat feeding strategy (DO-stat), where P. putida ${\Delta}gcd$ mutant strain showed a final PHA content and specific PHA productivity of 67% and $0.83g{\cdot}l^{-1}{\cdot}h^{-1}$, respectively. To our knowledge, this mcl-PHA titer is the highest value that has been ever reported using glucose as the sole carbon and energy source. Our results also highlighted the effect of different fed-batch strategies upon the extent of realization of the intended metabolic modification of the mutant strains.