• 생물환경조절학회지
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• 제10권3호
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• pp.197-206
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• 2001

오존층 파괴에 의해 지표면에 도달하는 자외선, 특히 UV-B(ultraviolet-B radiation, 280∼320nm)의 방사량이 증가하고 있다. UV-B는 유전자의 직접적인 손상, 호르몬 분해, 광합성 억제 등 생리·생화학적 대사기구에 영향을 미쳐 육상 생태계와 안정된 식량 확보에 큰 위협이 되고 있다. 그러나 식물은 UV-B에 대한 방어 기능을 갖고 있으며 형태적 적응, 광 회복 기능, UV-흡수물질의 생합성 촉진 등을 통해 UV-B로부터 생체를 보호한다.

• 한국물환경학회지
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• 제27권6호
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• pp.754-759
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• 2011

A sequencing batch reactor (SBR) was operated under different pH conditions to better understand the influence of pH to granulation in enhanced biological phosphorus removal systems. Granules from the SBR were also investigated using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Considerable decreases in the amount of phosphorus released per substrate provided under anaerobic conditions and the content of biomass polyphosphate under aerobic conditions were observed when pH was changed from 7.5 to 7.0, followed by 6.5. Aerobic granulation was also observed at pH 7.0. A number of bacteria with the typical morphological traits of tetrad-forming organisms (TFOs) were observed at pH 7.0, including large members of cluster. Filamentous bacteria were also there in large numbers. The occurrence and growth of granules were further enhanced at pH 6.5. A SEM analysis showed that the aerobic granules had a compact microbial structure with shaperical shape and morphologically consisted of aggregates of small coccoid bacteria and filamentous bacteria encapsulated by extracellular polymeric substance. The main material ions identified by EDX moreover revealed that the structural materials for polyphosphate in the granules include phosphorus, potassium and calcium. Therefore, these results strongly suggested that PAOs are a dominant population in the microbial community of the aerobic granules.

• Journal of Plant Biotechnology
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• 제50권
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• pp.215-224
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• 2023

Disinfecting water containing pathogenic microbes is crucial to the food safety of fresh green agricultural products. The UV-activated peracetic acid (UV/PAA) treatment process is an efficient advanced oxidation process (AOP) and a versatile approach to disinfecting waterborne pathogens. However, its effects on plant growth remain largely unknown. This study found that low-dose UV/PAA treatment induced moderate oxidative stress but enhanced the innate immunity of Arabidopsis against Pseudomonas syringae pv. (Pst) DC3000. When applied as water sources, 5- and 10-ppm UV/PAA treatments slightly reduced biomass and root elongation in Arabidopsis seedlings grown under hydroponic conditions. Meanwhile, treatments of the same doses enhanced defense against Pst DC3000 infection in leaves. Accumulation of hydrogen peroxide and callose increased in UV/PAA-treated Arabidopsis samples, and during the post-infection period, UV/PAA-treated seedlings maintained vegetative growth, whereas untreated seedlings showed severe growth retardation. Regarding molecular aspects, priming-related defense marker genes were rapidly and markedly upregulated in UV/PAA-treated Arabidopsis samples. Conclusively, UV/PAA treatment is an efficient AOP for disinfecting water and protecting plants against secondary pathogenic attacks.

• 대한환경공학회지
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• 제31권12호
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• pp.1075-1080
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• 2009

혐기성 소화 시 산발효 단계에서 지질 성분이 부분적으로 분해되고 지질 내 이중 결합이 포화됨을 통해 후단의 메탄발효 효율이 향상됨이 보고된 바 있다. 본 연구에서는 혐기성 연속 회분식 반응조(anaerobic sequencing batch reactor, 이하 ASBR) 및 연속 흐름 교반 반응조(continuously stirred tank reactor, 이하 CSTR) 형태의 산생성조를 각각 운전하여 지질 분해 및 독성 저감 효율을 살펴보았다. 기질로는 두 가지 불포화(oleate and linoleate), 두 가지 포화(palmitate and stearate) 지방산(long-chain fatty acids, 이하 LCFA)로 구성된 LCFA 혼합물을 사용하였다. 반응조 내의 높은 미생물 보유량에 의해 ASBR이 수리학적 체류시간(hydraulic retention time, 이하 HRT) 12 hr 이하에서 우월한 성능을 보였다. HRT 9시간에서 ASBR은 36.7%의 LCFA 분해, 14.3%의 이중결합 포화, 43.8%의 산생성 효율을 보였으며, 이는 HRT 15시간의 CSTR 보다 각각 19%, 10%, 21% 높은 수치였다. 지질 함유 폐수의 혐기성 소화 시 ASBR을 이용한 산발효가 효과적일 것으로 판단된다.

• Journal of Microbiology and Biotechnology
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• 제30권1호
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• pp.136-145
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• 2020

Chlorella sp. HS2, which previously showed excellent performance in phototrophic cultivation and has tolerance for wide ranges of salinity, pH, and temperature, was cultivated heterotrophically. However, this conventional medium has been newly optimized based on a composition analysis using elemental analysis and ICP-OES. In addition, in order to maintain a favorable dissolved oxygen level, stepwise elevation of revolutions per minute was adopted. These optimizations led to 40 and 13% increases in the biomass and lipid productivity, respectively (7.0 and 2.25 g l^-1d^-1 each). To increase the lipid content even further, 12 h heat shock at 50℃ was applied and this enhanced the biomass and lipid productivity up to 4 and 17% respectively (7.3 and 2.64 g l^-1d^-1, each) relative to the optimized conditions above, and the values were 17 and 14% higher than ordinary lipid-accumulating N-limitation (6.2 and 2.31 g l^-1d^-1). On this basis, heat shock was successfully adopted in novel Chlorella sp. HS2 cultivation as a lipid inducer for the first time. Considering its fast and cost-effective characteristics, heat shock will enhance the overall microalgal biofuel production process.

• KSBB Journal
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• 제4권2호
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• pp.87-93
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• 1989

불용성 기질인 섬유소의 고효율 효소당화에 적합한 분쇄마찰매체함유 반응장치의 개발을 목표로 섬유소-효소-분쇄마찰매체함유 반응장치의 개발을 목표로 섬유소-효소-분쇄마찰매체의 혼합액을 통자체를 회전시켜 교반마찰시키는 tumnling drum type bioreactor를 제작하여 그 효용성을 검토하였다. 반응조 내부의 구조 및 제반 운전조건하에서의 당생성 효울을 분쇄마찰매체의 교반에 소요되는 에너지와 비교분석 검토함으로써 공업적 규모의 활용을 위한 기술적, 경제적 타당성을 평가하였다. 3L규모의 장치의 경우 반응조내경과 baffle의 크기의 비가 1:0.05이고 8개의 baffle을 설치한 반응조에서 3mm glass bead를 600g/l로 첨가하여 100rpm으로 교반할 때 가장 우수한 결과를 얻었다. Tumbling drum type bioreactor는 매우 효율적인 attrition coupled된 당화장치로 판단되며, 특히 산업적 규모로 scale-up하기 용이한 구조를 갖고 있어 이에 대한 구체적 연구가 요망된다.

• ALGAE
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• 제37권3호
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• pp.213-226
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• 2022

Aquaculture is one of the fastest growing food producing sectors; however, intensive farming techniques of finfish have raised environmental concerns, especially through the release of excessive nutrients into surrounding waters. Biodiversity has been widely shown to enhance ecosystem functions and services, but there has been limited testing or application of this key ecological relationship in aquaculture. This study tested the applicability of the biodiversity-function relationship to integrated multi-trophic aquaculture (IMTA), asking whether species richness can enhance the efficiency of macroalgal bioremediation of wastewater from finfish aquaculture. Five macroalgal species (Chondrus crispus, Fucus serratus, Palmaria palmata, Porphyra dioica, and Ulva sp.) were cultivated in mono- and polyculture in water originating from a lumpfish (Cyclopterus lumpus) hatchery. Total seaweed biomass production, specific growth rates (SGR), and the removal of ammonium (NH₄⁺), total oxidised nitrogen (TON), and phosphate (PO₄^3-) from the wastewater were measured. Species richness increased total seaweed biomass production by 11% above the average component monoculture, driven by an increase in up to 5% in SGR of fast-growing macroalgal species in polycultures. Macroalgal species richness further enhanced ammonium uptake by 25%, and TON uptake by nearly 10%. Phosphate uptake was not improved by increased species richness. The increased uptake of NH₄⁺ and TON with increased macroalgal species richness suggests the complementary use of different nitrogen forms (NH₄⁺ vs. TON) in macroalgal polycultures. The results demonstrate enhanced bioremediation efficiency by increased macroalgal species richness and show the potential of integrating biodiversity-function research to improve aquaculture sustainability.

• Carbon letters
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• 제25권
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• pp.103-112
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• 2018

Hierarchically porous, chemically activated carbon materials are readily derived from biomass using hydrothermal carbonization (HTC) and chemical activation processes. In this study, empty fruit bunches (EFB) were chosen as the carbon source due to their sustainability, high lignin-content, abundance, and low cost. The lignin content in the EFB was condensed and carbonized into a bulk non-porous solid via the HTC process, and then transformed into a hierarchical porous structure consisting of macro- and micropores by chemical activation. As confirmed by various characterization results, the optimum activation temperature for supercapacitor applications was determined to be $700^{\circ}C$. The enhanced capacitive performance is attributed to the textural property of the extremely high specific surface area of $2861.4m^2\;g^{-1}$. The prepared material exhibited hierarchical porosity and surface features with oxygen functionalities, such as carboxyl and hydroxyl groups, suitable for pseudocapacitance. Finally, the as-optimized nanoporous carbons exhibited remarkable capacitive performance, with a specific capacitance of $402.3F\;g^{-1}$ at $0.5A\;g^{-1}$, a good rate capability of 79.8% at current densities from $0.5A\;g^{-1}$ to $10A\;g^{-1}$, and excellent life cycle behavior of 10,000 cycles with 96.5% capacitance retention at $20A\;g^{-1}$.

• ALGAE
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• 제21권3호
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• pp.333-341
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• 2006

The productivities of Chlorella ovalis and Dunaliella parva were influenced by the rates of medium compositions obtained from the fermented animal wastewater (BM: bacteria mineral water) including a natural substitute chelator for EDTA (etylenediaminetetraacetic acid). The most favorable medium was -E+50 adding 50% BM in f/2 medium instead of EDTA, a chemical chelator, which increased more 19-fold of cell density in C. ovalis and 7-fold in D. parva than cells cultured on f/2 medium as well as the enhancements of chlorophyll a (f/2-E: 0.26 g L–1, -E+50: 1.5 g L–1 in C. ovalis; f/2-E: 2.7 g L–1, -E+50: 15 g L–1 in D. parva) and the increase of maximal PSII quantum yields. These results were verified that the BM could play an important part as a natural chelator substituted for EDTA. In the fields of biotechnology, food organisms in fishery and eco-industries of CO2 sequestration in air and nutrient removal in water, the natural chelator of BM could be applied to enhance the biomass of the other microalgae.

• 상하수도학회지
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• 제30권1호
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• pp.99-104
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• 2016

This study was performed to develop a new process technology for advanced wastewater treatment using a modified Rotating Activated Bacillus Contactor (RABC) process that adopts anoxic-oxic suspended biomass tanks to enhance nutrients removal. A modified lab-scale RABC process was applied to examine its applicability and to obtain the design factors for the optimum operation of the system. The modified RABC process showed a little more stable and high nutrients removal efficiency than the prototype RABC process: about 70% of nitrogen and 55% of phosphorous removal when the low organic loading (influent COD 200mg/L). However, the processing efficiency of nutrients removal rates was enhanced to great extent when high organic loading: nitrogen 90% and phosphorous 85% (influent COD 500mg/L). High organic loading stimulated extremely good biomass attachment on the reticular carrier RABC stage and the excellent nutrients removal, nevertheless with almost no offensive odor.