• 한국토양비료학회지
• /
• 제49권6호
• /
• pp.776-782
• /
• 2016

Salinity has been a threat to agriculture in some parts of the world; and recently, the threat has grown. Plant growth-promoting rhizobacteria (PGPR) may benefit plant growth, either by improving plant nutrition or producing plant growth hormones. The effects of rhizobacterial strains to attenuate the salinity stress on the germination of Chinese cabbage seeds were tested using four different concentrations of NaCl (50, 100, 150, and 200 mM). Also, PGPR strains were tested to enhance the early germination of Chinese cabbage seeds under normal conditions. Azotobacter chroococcum performed best with enhancing the radicle length of 4.0, 1.2, and 1.0 times at treatments of 50, 100, and 150 mM of NaCl, respectively. Additionally, significant differences were found in plumule length, A. chroococcum and Lactobacillus sp. showed remarkable activation either in normal or under stress conditions. Co-inoculation by three rhizobacterial strains (LAPmix) indicated synergistic effect to enhance the early germination of the seeds. The results of this study are promising for application of rhizobacterial strains that possess plant growth promoting traits to enhance the plant tolerance against salinity.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제22권2호
• /
• pp.17-25
• /
• 2017

The efficiency and mechanism of electrochemical phenol oxidation using persulfate (PS) and nanosized zero-valent iron (NZVI) were investigated. The pseudo-first-order rate constant for phenol removal by the electrochemical/PS/NZVI ($1mA^*cm^{-2}/12$ mM/6 mM) process was $0.81h^{-1}$, which was higher than those of the electrochemical/PS and PS/NZVI processes. The electrochemical/PS/NZVI system removed 1.5 mM phenol while consuming 6.6 mM PS, giving the highest stoichiometric efficiency (0.23) among the tested systems. The enhanced phenol removal rates and efficiencies observed for the electrochemical/PS/NZVI process were attributed to the interactions involving the three components, in which the electric current stimulated PS activation, NZVI depassivation, phenol oxidation, and PS regeneration by anodic or cathodic reactions. The electrochemical/PS/NZVI process effectively removed phenol oxidation products such as hydroquinone and 1,4-benzoquinone. Since the electric current enhances the reactivities of PS and NZVI, process performance can be optimized by effectively manipulating the current.

• 한국약용작물학회지
• /
• 제25권2호
• /
• pp.115-120
• /
• 2017

Background: The study aimed to obtain data on the effects of cultivation and soil reduction of green manure crop on the quantity and quality of organically cultivated Cynanchum wilfordii Hemsley. Methods and Results: The experiment comprised four treatments: control, hairy vetch, barley, and hairy vetch + barley (3 : 2). The plant height in the hairy vetch treatment (86.3 cm) was significantly different from that in the other treatments, whereas the stem diameter leaf area, and special product analysis division (SPAD) value did not differ across the treatments. The largest soil reduction of green manure crop was recorded in the barley treatment (440 kg/10 a), whereas the smallest was recorded in the single treatment with hairy vetch (80 kg/10 a). The hairy vetch + barley (60 : 40) treatment showed 63% more soil microorganisms than control. Radical scavenging activity estimation revealed that the total polyphenol content was highest (1,740 mg/kg), and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) was 92.6% in the barley treatment. The 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) activation was highest in the control (51.1%), and the root yield was the highest in the barley treatment (310 kg/10 a). Conclusions: The root yield, total polyphenol content, and antioxidant activity of Cynanchum wilfordii (Maxim.) Hemsley increased in presence of the green manure crop barley.

• 한국산학기술학회논문지
• /
• 제13권12호
• /
• pp.6151-6158
• /
• 2012

친환경 하천사업의 활성화로 식생매트의 사용은 증가하고 있으나 수리적 안정성에 대한 평가는 미흡한 실정이다. 본 연구는 호안용 식생매트 제품의 객관적인 수리안정성 시험 기법 개발을 위해 수행하였다. 이를 위해서 식생매트 2종에 대한 실규모 실험을 수행하여 수리량을 측정하고 분석하여 작용 소류력을 계산하였다. 1차원 부정류 모형을 이용하여 최적 조도계수를 결정하고 작용 소류력을 계산하였다. 각 유량의 시험 후에는 매트 표면 및 기반층의 변동 여부를 기록하여 평가하였으며 이에 따라 매트표면의 손상 유형 3가지 및 기반층의 손상 유형 2가지를 제시하였다. 본 연구에서는 식생매트의 표면 변동이 있더라도 하부 기반층의 유실이 발생하지 않는 경우에는 안정한 상태로 제안하였다. 이에 따라 실험체 2종의 허용소류력을 평가하였으며 철망으로 보강된 식생매트가 허용 소류력 측면에서 효과가 있는 것을 확인할 수 있었다.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제26권1호
• /
• pp.54-64
• /
• 2021

The chemical warfare agents (CWAs) have been developed for offensive or defensive purposes and used as chemical weapons in war and terrorism. The CWAs are exposed to the natural environment, transported through the water system and then eventually contaminate soil and groundwater. Therefore, effective decontamination technology to remediate CWAs are needed. The CWAs are extremely dangerous and prodution is strictly prohibited, therefore, it is difficult to use CWAs even in experimental purpose. In this study, 2,4-dichlorophenoxyacetic acid (2,4-D) was chosen as a model representative CWA because it is a simulant of anti-plant CWAs and one of the major component of agent orange. The optimum degradation conditions such as oxidant:activator ratio were determined. The effects of hydroxylamine and chelating agents such as citric acid (CA), oxalic acid (OA), malic acid (MA), and EDTA addition to increase Fe2+ activation were also investigated. Scavenger experiments using tert-butyl alcohol (TBA) and ethanol confirmed that although both sulfate (SO4•-) and hydroxyl radical (•OH) existed in Fe2+-persulfate system, sulfate radical was the predominant radical. To promote the Fe2+ activator effect, the effect of hydroxylamine as a reducing agent was investigated. In chelating agents assisted Fe2+-persulfate oxidation, the addition of 2 mM of CA and MA enhanced 2,4-D degradation. In contrast, EDTA and OA inhibited the 2,4-D removal due to steric hindrance effect.

• 한국미생물·생명공학회지
• /
• 제23권2호
• /
• pp.243-248
• /
• 1995

Agrochemicals for the plant-disease control are criticized severely for causing environmental pollution and residual problems, and consequently microbial disease control agents are expected to be safer and more economical for sustainable agriculture. Treatment of biological control agents to seed requires the use of effective delivery systems that allow full expression of the benefical qualities of the bioprotectant. For the activation and establishment of bioprotectant around the plant seed which are able protect the seeds and seedlings from pathogen attack, the optimal liquid coating formulation was obtained using 2% sodium carboxymethyl cellulose (binder), 20% sesame dregs (solid particulate material), and dried spore of Bacillus subtilis YBL-7 (bioprotectants, 10 mg/g of seed). Suppressive of root rot was demonstrated in pot trials with coated kidney bean (Phaseolus vulgaris L.) seeds. Coated seeds with B. subtilis YBL-7 spore in F. solani-infested soil reduced disease incidence by 85% to 90% after 30 days.

• 한국미생물·생명공학회지
• /
• 제22권1호
• /
• pp.65-72
• /
• 1994

Purification and characterization of pectate lyase from Bacillus sp HSA-925. Bacillus sp. HSA-925 isolated from soil produced constitutively an extracellular pectate lyase when cultivated in LB broth. The pectate lyase(EC 4.2.2.2) was purified from the cuylture broth by preciptation with ammonium sulfate, followed by column chromatography on CM-cellulose C-50 and repeated gel filtration on Sephadex G-75G. The enzyme had a molecular weight of 32-33 kDa. The activity was mazimum at pH 9.5 AND 45$\CIRC $C. The enzume activity was stable at 55$\circ $C for 15 min and between pH7-12. The activation energy, Km and V$_{max}$ for the pectate lyase were 5.8779 kcal/mol, 6.33$\times $10$^{-2}$ mol/ml and 2.09$\times $10$^{2}$ $\mu $mol/min respectively. The enzyme was activated by Ca$^{2+}$, Cu$^{2+}$ and inhibited by Li$^{+}$, Hg$^{2+}$, EDTA.

• 한국식품영양학회지
• /
• 제7권2호
• /
• pp.119-123
• /
• 1994

Aspergillus sp. BY-54 which produced a strong dextran hydrolyzing enzyme was isolated from soil. Using this strain, the optimal cultural conditions, enzyme purification and characterization were studied. The results are as follows : The optimal concentration of dextran as carbon source was l%. and the optimum temperature and the initial pH for enzyme production was 3$0^{\circ}C$, and 7.0, respectively. Dextranase was purified by DEAE-cellulose column chromatography with a linear gradient increase in NaCl. Km value of dextranase was 0.222%, and several glucans containing various types of glucosidic linkages such as DEAE-sephadex, CM-sephadex and sephadex G-100 were almost digested to a large extent with this dextranase. The enzyme was strongly inhibited by sodium fluoride, KMnO4 and p-CMB, while KCN caused 20% of activation.

• 식물병연구
• /
• 제30권2호
• /
• pp.181-188
• /
• 2024

Southern blight, caused by the soil-borne fungus Sclerotium rolfsii, is a serious disease that affects many economically important crops. In this study, we selected Bacillus subtilis GJ6-14, from a total of 260 strains, to control Southern blight in pepper plants. In both seedling and plant tests, GJ6-14 significantly suppressed disease incidence and severity compared to control, furthermore, GJ6-14 demonstrated efficient colonization in the rhizosphere by maintaining the population from log 5.41 to log 3.92 in the pathogen-inoculated plants, indicating its potential as a biocontrol agent. Molecular analysis revealed up-regulation of defense-related genes, such as a 7.6-fold increase in LOX1 and 15.5-fold increase in PR1, at 72 hr after inoculation of S. rolfsii in GJ6-14-treated plants, suggesting activation of plant defense mechanisms. Overall, our findings highlight the promising role of B. subtilis GJ6-14 as a potential biocontrol agent in sustainable management of Southern blight in pepper plants.

• 한국지반공학회논문집
• /
• 제34권6호
• /
• pp.17-24
• /
• 2018

순환 유동층 보일러의 연소재를 고로슬래그의 알칼리 활성화 반응 자극제로 활용하여 개발한 새로운 매입말뚝의 주면고정액(ZA-Soil)을 시멘트밀크 공법의 주면고정액으로 사용한 말뚝에 대하여 정재하시험 및 동재하시험을 실시하여 보통 포틀랜드시멘트(OPC)와 비교하여 성능을 평가하였다. 정재하시험을 수행한 결과 말뚝의 허용하중은 1,350kN로 보통 포틀랜드시멘트를 매입말뚝의 주면고정액으로 사용한 결과와 동일하였고, 전 침하량은 6.97mm, 순 침하량은 1.48mm로 보통 포틀랜트시멘트의 전 침하량 7.825mm, 순 침하량 2.005mm와 유사한 결과를 보이는 것으로 나타났다. 동재하시험 및 CAPWAP분석을 실시한 결과, 새로운 매입말뚝의 주면고정액(ZA-Soil)의 주면 마찰력은 375.0kN, 선단 지지력은 3,045.9kN, 허용지지력은 1,368.36kN으로 나타났고, 포틀랜드시멘트를 매입말뚝의 주면고정액으로 사용한 결과와 유사한 결과를 보이는 것으로 나타났다.