• 한국대기환경학회지
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• 제14권6호
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• pp.599-606
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• 1998

Removal of toluene vapor from airstreams was studied in a biological reactor known as a biofilter. The biofilter was packed porous ceramic inoculated with thickened activated sludge (MLVSS 17,683 mg/L). The lab-scale biofilter was operated for 42 days under various experimental conditions including inlet toluene concentrations and flow rates of the contaminated air streams. Removal efficiency reached up 96.6% after 4 days from start up. Nutrient limitation was proposed as a reason for the decrease in biofilter performence. Biofilter performance decreased substantially, coincident with the buildup of back pressure due to accumulation of excess VSS within the medium bed. Practically, the bed needs to be backwashed when the overall pressure drop is greater than 460.6 Pa at SV (Space Velocity) 100 h-1. Periodic backwashing of the biofilter was necessary for removing excess biomass and attaining stable long -term high removal efficiency The removal efficiency of toluene in the biofilter decreased as the gas velocity and toluene concentration in the inlet gas increased. The maximum elimination capacity of ceramic biofilter could reach up to 444.85 g/m3. hr. When the loading of toluene exceed this critical value, substrate inhibition occurred.

• Ocean and Polar Research
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• 제23권4호
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• pp.401-410
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• 2001

Global climate change will alter many such properties of the Southern Ocean as temperature, circulation, stratification, and sea-ice extent. Such changes are likely to influence the species composition and activity of Antarctic marine microorganisms (protists and bacteria) which playa major role in deter-mining the concentration of atmospheric $CO_2$ and producing precursors of cloud condensation nuclei. Direct impacts of climate change on Antarctic marine microorganisms have been determined for very few species. Increasing water temperature would be expected to result in a southward spread of pelagic cyanobacteria, coccolithophorids and others. Growth rates of many species would be expected to increase slightly but nutrient limitation, especially micronutrients, is likely to result in a negligible increase in biomass. The extent of habitats would be reduced for those organisms presently living close to the upper limit of their thermal tolerance. Increased UVB irradiance is likely to favour the growth of those organisms tolerant of UVB and may change the trophic structure of marine communities. Indirect effects, especially those as a consequence of a diminution of the amount of sea-ice and increased upper ocean stratification, are predicted to lead to a change in species composition and impacts on both trophodynamics and vertical carbon flux.

• 한국물환경학회지
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• 제28권2호
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• pp.300-304
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• 2012

It has a limitation to satisfy the phosphorus effluent criteria of 0.2 mg/L which will be reinforced from 2012 with the Biological Nutrient Removal (BNR) process. The chemical coagulation process has been operated in parallel with the biological treatment process for advanced treatment of phosphorous in the developed countries including Europe. However, the coagulation process has some disadvantages such as the desired goal may not be achieved without injecting the optimum dosage of the coagulant. This study developed the automatic control system to inject the optimum dosage of phosphorous coagulant into the coagulation process. The adopted coagulant was 10% Poly Aluminum Chloride (PAC) in this study. The automatic control system developed in this study was adopted for the treatment of the phosphorus from the effluent in SBR process. The automatic control system was composed of the data receiving part, the optimum coagulant dosage control part and the data transmit part. The result of the phosphorous advanced treatment of the SBR effluent using the automatic control system showed the removing efficiency over 95% consistently with the phosphorous concentration under 0.02 ~ 0.15 mg/L. The reproducibility analysis for checking the safety of automatic control system showed more than 95% correlation.

• 한국환경과학회지
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• 제17권3호
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• pp.269-273
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• 2008

The objective of this study was to evaluate the relationship between nutrients and phytoplankton. This study was done by the comparison to two costal areas Mokpo, which inflow fresh water, and Wando. In August, salinity of the sea water decreased by 3.5-4.5%o in Mokpo coastal area, but was not nearly decreased in Wando coastal area. This suggests a lot of fresh water inflow in Mokpo coastal area. DIN and DIP were decreased by water temperature increasing in Wando. However, in Mokpo, DIN and DIP were increased greatly during the summer season. Nitrogen was limited to a 10 NIP ratio especially during the summer season in Wando coastal area while phosphorus in Mokpo coastal area was limited with over 28 N/P ratio in all the seasons. Coefficient of determination$(r^2)$ between DIP and Chl.-a was 0.91 in Mokpo coastal area. On the other hand, Coefficient of determination$(r^2)$ between Chl.-a and DIN, DIP were 0.93 and 0.89, respectively, in Wando coastal area. These results suggest DIP in Mokpo and DIN and DIP in Wando might be limited at the increase of phytoplankton.

• 한국지역사회생활과학회지
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• 제17권1호
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• pp.87-99
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• 2006

The purpose of this study was to explore the relationship between self-rated health and Activity of Daily Living (ADL) and self-care behavior of rural elderly in Korea, focused on the difference among three distinctive living arrangements; living alone, living only with his/her spouse, and living with their married children. For this purpose, data were gathered from a nationwide survey, a total of 586 elderly aged 65 or older and living in rural area, using the structured questionnaire. Also, self-care behavior were categorized into 4 groups; life-style practice, medical self-care, adaption to functional limitation, and emotional management. The major findings are as follows; 1) Rural elderly perceived their health little and more 'bad' but their ADL capacity were 'not difficult', especially among elderly living with spouse. 2) The level of 20 items in self-care behavior ($1{\sim}5$score) was ranged from 2.51 to 3.81 score. The behavior level of regular exercise, setting up additional phone, taking a nutrient, and testing BP or pulse regularly were low but that of taking a medicine according to prescription, close contact with other people, and regular eating were proportionally high. 3) The majority of self-care behavior were correlated with subjective health positively but medical self-care behavior were correlated with subjective health or ADL negatively. Based on these results, policy implications are discussed.

• Journal of Microbiology and Biotechnology
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• 제14권4호
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• pp.859-862
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• 2004

An isolate of Pseudomonas putida has been found to aggressively colonize root tips and induce plant resistance to Fusarium wilt. However, P. putida mutants lacking Fe-superoxide dismutase (SOD) or both FeSOD and MnSOD activities are less competitive in root tip colonization. In the current study, the growth of an FeSOD mutant was found to be more sensitive than that of the wild-type or a MnSOD mutant to oxidative stress imposed by paraquat treatment and culturing with the soil fungus Talaromyces flavus, which generates reactive oxygen species. Also, the loss of culturability with an aging stationary-phase culture was greater for a double SOD mutant than an FeSOD mutant, while no reduction in culturability was observed with the wild-type and a MnSOD mutant under the same protracted stationary-phase conditions. Accordingly, it was concluded that FeSOD activity is the major form of SOD in P. putida and plays an essential role in survival under stress conditions when increased oxidative stress is encountered.

• 미생물학회지
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• 제42권4호
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• pp.239-245
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• 2006

Leucine-responsive Regulatory Protein (Lrp)는 global 조절 단백질로서 아미노산의 합성 및 분해 작용과 pilin 생합성을 포함하는 다양한 대사기능을 조절하는데 관여한다. 또한 Lrp가 대장균의 성장 정지기의 유전자 발현에 매우 중요한 역할을 하는 것으로 최근의 여러 실험 결과에서 밝혀지고 있다. 따라서 본 총설에서는 세균들이 영양부족 등의 환경적인 스트레스상황을 어떻게 인지하고 유전자 발현 조절에 그 정보를 반영해 나가는지를 제시해 주는 종은 모텔 시스템으로서 Lrp의 생화학적 특성을 기술하였다.

• ALGAE
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• 제21권2호
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• pp.253-259
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• 2006

Organic substances are released from phytoplankton cells during all phases of growth. The type and amounts of organic substance excreted and the effects of nutrient limitation are often highly species-specific. Dinoflagellate, Cochlodinium polykrikoides grown in batch culture produced an exopolysaccharide. Exopolysaccharide and intracellular polysaccharide concentrations increased as C. polykrikoides cultures progressed from exponential phase, through stationary phase, to declining phase. In the exponential phase, the concentration of exopolysaccharide was relatively low, but in the stationary phase, it showed a rapid increase which seemed to coincide with the depletion of nitrate from the medium. Of the 20 amino acids analyzed, proline dominated in the organic matter of all cultures ranging from 48.2 to 79.9 nmol L–1, and constituting the 20-90% of total amino acids, and followed by histamine varying from 0.7 to 47.5 nmol L–1. Leucine and cysteine were also abundant in the stationary phase. The release rates of exopolysaccharide and intracellualr polysaccharide were higher the end of stationary phase than in the exponential phase. Exopolysaccharide concentration per cell was more than two times higher during the end of stationary phase than that in exponential phase. C. polykrikoides produced extracellular polysaccharide at a rate of 47.04 pg cell–1 day–1.

• 한국염색가공학회지
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• 제34권4호
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• pp.302-311
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• 2022

Increase of population, lack of land, and decrease in fertility of soil have caused the limitation of food production across the globe. This leads to developing alternative foods, at the same time, vegan society have been got bigger. They argue for animal's right to life and happiness, dissent from breeding and improving livestock, and proscribe eating meat. Emerging problem concerns their health as many turn to vegan society. Only intaking vegetable protein can cause health problems, leading to the development of novel food replacing meat. The most promising candidate is non-slaughtered cultured meat which can be produced in a laboratory. The cultured meat enables it to keep its texture, nutrient, and taste while also addressing the problems of breeding stock and slaughter. We have discussed the cultured meat industry from the perspective of a vegan society, and the prospects were considered from various aspects of awareness and preference.

• 생태와환경
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• 제39권1호통권115호
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• pp.119-130
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• 2006

연속배양의 평형 정상상태 조건에서 담수조류 Microcystis aeruginosa의 최대생장률 (${\mu}_m$)과 세포내 영양염의농도(Q)의 관계, 질소 결핍 상태에서 액체배지에서 영양염 농도(S)와 홉수율(V)의 관계를 각각 조사하였다. 질소제한조건에서 M. aeruginosa의 세포 당 $Q_{0N}$은 0.04 pmol $cell^{-1}$. ${\mu}_m$은 1.1 $day^{-1}$였고, 제한조건에서 최저값 $Q_{0N}$과 충분조건에서 $Q_N$을 탄소기준하여 각각 6.1 ${\mu}mol$ mg $C^{-1}$ 및 9.5${\sim}$12.4 ${\mu}mol$ mg $C^{-1}$였다. 다른 미세조류와 비교f'1면 세포의 질소 함량이 매우 높았고 질소 결핍시에도 그 함량이 높게 유지되어 질소 요구도가 높은 종이었다 질소 제한조건에서 영양염 홉수 측정 결과에서 반포화계수($K_s$)와 최대흡수율 ($V_m$)은 각각 36 ${\sim}$ 61 ${\mu}M$ 및 0.28 ${\sim}$ 0.35 ${\mu}mol\;cell\;{\cdot}\;hr^{-1}$ 범위였다. M. aeruginosa의 $K_5$값은 매우 높았고 $V_m$도 높은 편이었다. $K_s$와 흡수력 $V_m$은 미세조류의 영양상태 즉 영양염의 세포내 함량(Q)이나 제한영양염의 결핍의 강도의 영향을 받고 미세조류 생장균과도 관련이 있다. M. aeruginosa는 다른 미세조류에 비하여 세포내 질소 함량과 생장률이 높기 매문에 질소와 인에 대한 횹수율이 높을 것이다. 그러나 질소 흡수력의 반포화계수 $K_s$값이 높고 $V_m/K_s$비율은 낮아 수게에서 질소가 저농도 일 때에는 다른 미세조류와 비교하면 경쟁력이 떨어지고 질소에 대한 기질 친화력은 약한 것으로 나타났다. 낙동강 하류지역에서 M. aeruginosa가 대발생하는 시기에 수중 영양염의 농도 변동은 M. aeruginosa의 영양생리 kinetics 특성과 잘 부합하는 것으로 나타났다.