• 유기물자원화
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• 제16권3호
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• pp.75-82
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• 2008

상향류 혐기성 슬러지 블랭킷 반응조을 이용한 프로피온산의 처리시 고농도 황산염의 영향을 조사하였다. 반응조의 평균 유기물 부하와 수리학적 체류시간은 $1.2kg \;COD/m^3{\cdot}d$와 1.6일로 유지하였다. 황산염이 없는 조건에서 UASB 반응조의 경우 95%의 COD 제거율을 보였으며 황산염이 $2,000mgSO_4^{2-}/L$로 존재하는 경우 용존 황화물의 영향으로 COD 제거율이 83%로 감소하였다. 메탄 생성균과 황산염 환원균의 경쟁관계를 평가하기 위하여 미생물의 상호작용에 관해 조사하였다. $COD/SO_4^{2-}$ 비가 1인 경우 이용 가능한 전자 수용체의 평균 58%가 메탄 생성균에 의해 이용되며 나머지가 황산염 환원균에 의해 사용되었다. 초산과 프로피온산을 기질로 이용한 비메탄 활성도의 경우 미생물이 기질에 적응함에 따라 증가하였다.

• 한국대기환경학회지
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• 제27권6호
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• pp.703-710
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• 2011

Odor emission from domestic sewer systems has become a serious environmental problem. An investigation on a sewer manhole revealed that anaerobic decay of sediment organic matters (SOMs) and related declines of oxidation reduction potential (ORP) in the sediment layer were the main reason of the production of volatile sulfur compounds. In addition, as the anaerobic decaying period continued, the odor intensity rapidly increased with increasing concentrations of $H_2S$ and dimethyl sulfide. As a feasible method to control SOMs and to minimize odor emission potentials, an electrolytic oxidation process has been employed to the sediment sludge phase. In this study, voltages applied to the electrolytic oxidation process were varied as a main system parameter, and its effects on odor removal efficiencies and reaction characteristics were investigated. At the applied voltages greater than 20 V, the system efficiently oxidized the organic matter, and the ORP in the sludge phase increased rapidly. As a consequence, the removal efficiency of hydrogen sulfide was found to be >99% within 60 minutes of the electrolytic oxidation. Overall, the electrolytic oxidation process can be an alternative to control odor emission from sewer systems, and a threshold input energy needs to be determined to achieve effective operation of the process.

• 대한화학회지
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• 제17권3호
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• pp.188-192
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• 1973

Trimethylsilylethylsulfide, trimethylsilylphenylsulfide, triethylstannylethylsulfide 그리고 triethylstannylphenysulfide를 10일간 여러온도에서 isocyanate와 각각 반응시켰다. 이들 Si-S와 Sn-S결합 유기금속화합물들은 phenylisocyanate의 이량체, 삼량체, diphenylcarbodiimide 및 1,3,5-triphenyl-4-phenyliminohexahydro-1,3,5-triazine-2,6-dione의 생성 촉매로 작용하였다. 반면 이 화합물들은 ethylisocyanate로부터는 삼량체인 triethylisocyanurate만을 생성하였다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.532-535
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• 2003

Indigenous bacterial mediation of As in contaminated sediment after biostimulation with a variety of carbon sources was investigated under aerobic and anaerobic conditions. Under the aerobic condition with lactate supply, indigenous bacteria increased the amount of total As extracted from the sediment and most dissolved As existed as As(V). Under the anaerobic, glucose-supplied condition, dissolved As diminished with time likely due to production of As sulfide(s) and subsequent precipitation, which resulted from bacterial reduction of ${SO_4}^{2-}$. The results implied that bacterial natural attenuation of As in subsurface has a potential to be practically applied.

• 환경생물
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• 제18권4호
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• pp.441-446
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• 2000

Trichoderma harzianum is an aggressive causal agent of green mold disease on mushroom cultivation. Some bacterial strains isolated, from oyster mushroom compost in Wonju, were found to have in vitro antifungal activity against Trichoderma harzianum ATCC 6385, 6504, and our isolates Trichoderma spp. Y and G. Further in vitro antifungal studies on several strains of phytopathogenic fungi showed that all of 12 phytopathogenic fungal strains were significantly inhibited by the isolated antifungal bacteria in Petri dishes. Of these, KATB 99121 showed the broadest inhibiting effect and displayed as negative coagulase, negative sulfide production and rod shape. KATB 99121 was resistant to ampicillin, chlorampenicol, and kanamycin. Identification of isolates was determined by Biolog GN system, and KATB 99121 was identified as Photobacterium logei because of 96 probability, 0.65 similarity, and 4.97 disturbance. With electron microscopy, thin section of KATB 99121 strain revealed typical rod-like shaped cell (0.6-0.8${\mu}{\textrm}{m}$$\times$1.5-2.0${\mu}{\textrm}{m}$) with prokaryotic structure and organization.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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• pp.111-114
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• 2006

The effects of indigenous bacteria on geochemical behavior of As in As-contaminated sediments (Hwachon mine and Myoungbong mine) after biostimulation with a variety of carbon sources were investigated under anaerobic condition. In Hwachon sediment, As was dramatically extracted from nonsterile sediment with time, reaching the highest concentration of $500{\mu}g/L$. The As leaching was likely caused by microbial dissolution of Fe oxides/oxyhydroxides with which As had been coprecipitated. However, in the case of Myoungbong sediment supplied with glucose, dissolved As decreased with time likely due to production of As sulfide(s) and subsequent precipitation, which resulted from bacterial reduction of $SO_4^{2-}$. The results implied that bacterial in-situ stabilization of As In subsurface has a potential to be practically applied.

• Natural Product Sciences
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• 제26권1호
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• pp.10-27
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• 2020

Endophytes are defined as microorganisms that spend part of lifetime interior of plant tissues without causing negative effects. They have been used for agricultural purpose, biofuel production, bioremediation, medication, etc. In particular, endophytes have been emerged as a good source for bioactive secondary metabolites. A large number of secondary metabolites are currently being reported. In this report, we focus on the secondary metabolites that were originated from endophytic fungi inhabiting medicinal plants. They were classified into several groups such as nitrogenous compounds, steroids, sulfide-containing metabolites, terpenoids, polyketides, and miscellaneous for discussion of chemical structures and biological activities.

• 한국분말재료학회지
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• 제25권1호
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• pp.60-68
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• 2018

The design and fabrication of photoelectrochemical (PEC) electrodes for efficient water splitting is important for developing a sustainable hydrogen evolution system. Among various development approaches for PEC electrodes, the chemical vapor deposition method of atomic layer deposition (ALD), based on self-limiting surface reactions, has attracted attention because it allows precise thickness and composition control as well as conformal coating on various substrates. In this study, recent research progress in improving PEC performance using ALD coating methods is discussed, including 3D and heterojunction-structured PEC electrodes, ALD coatings of noble metals, and the use of sulfide materials as co-catalysts. The enhanced long-term stability of PEC cells by ALD-deposited protecting layers is also reviewed. ALD provides multiple routes to develop improved hydrogen evolution PEC cells.

• Ocean and Polar Research
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• 제44권1호
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• pp.1-11
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• 2022

Hypoxia can affect water-atmosphere methane flux by controlling the production and consumption processes of methane in coastal areas. Seasonal methane concentration and fluxes were quantified to evaluate the effects of seasonal hypoxia in Dangdong Bay (Gyeongsangnamdo, Jinhae Bay, South Korea). Sediment-water methane flux increased more than 300 times during hypoxia (normoxia and hypoxia each 6, 1900 µmol m^-2 d^-1), and water-atmospheric methane flux and bottom methane concentration increased about 2, 10 times (normoxia and hypoxia each 190, 420 µmol m^-2 d^-1; normoxia and hypoxia each 22, 230 nM). Shoaling of anaerobic decomposition of organic matter in the sediments during the hypoxia (August) was confirmed by the change of the depth at which the maximum hydrogen sulfide concentration was detected. Shoaling shortens the distance between the water column and methanogenesis section to facilitate the inflow of organic matter, which can lead to an increase in methane production. In addition, since the transport distance of the generated methane to the water column is shortened, consumption of methane will be reduced. The combination of increased production and reduced consumption could increase sediment-aqueous methane flux and dissolved methane, which is thought to result in an increase in water-atmospheric methane flux. We could not observe the emission of methane accumulated during the hypoxia due to stratification, so it is possible that the estimated methane flux to the atmosphere was underestimated. In this study, the increase in methane flux in the coastal area due to hypoxia was confirmed, and the necessity of future methane production studies according to oxygen conditions in various coastal areas was demonstratedshown in the future.

• 콘크리트학회논문집
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• 제20권4호
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• pp.495-502
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• 2008

본 연구에서는 황산화세균의 생장과 이에 따른 콘크리트의 생화학적 부식의 단계적인 개연성을 실증적으로 분석하기 위해 고안된 생화학적 부식 시뮬레이션 시험 및 장치를 구축하였으며, 황산화세균인 Thiobacillus novellus의 생장 활성화를 위해 여러 기본조건을 설정하였다. 또한 세균의 이식 방법과 황화수소농도 조건에 따라 크게 2종류의 시험이 진행되었으며, 이에 따른 Thiobacillus novellus의 생장특성과 항균금속의 첨가에 따른 항균성능을 검증할 수 있었다. 우선 황화수소 120 ppm의 조건하에서 시험체를 세균배양액에 침지시켜 Thiobacillus novellus을 간접적으로 이식한 시뮬레이션 시험의 경우, 사슬형태의 대단위 군집을 형성하는 Thiobacillus novellus의 급속한 생장과 높은 황원소의 검출을 관찰할 수 있었으나 장기적으로 Thiobacillus novellus의 생장을 유도하기는 곤란하였다. 황화수소 50 ppm의 조건하에서 황산화세균인 Thiobacillus novellus를 직접 이식한 시뮬레이션 시험의 경우, Thiobacillus novellus의 비교적 장기적인 개별생장이 관찰되었으며, 항균금속을 첨가한 시험체에서 세포막과 내부 조직이 파괴된 Thiobacillus novellus의 개체가 관찰되어 항균금속 성분에 의한 Thiobacillus novellus의 생장억제 성능을 실증적으로 검증하는 것이 가능하였다.