• Title/Summary/Keyword: Biological degradation

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A Study on Microbial Degradation for Removal of Toluene Vapour by Biofilter (Bio 필터를 이용한 Toluene 제거에서 미생물분해에 관한 연구)

  • 하상안;강신묵
    • Journal of environmental and Sanitary engineering
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    • v.14 no.1
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    • pp.24-30
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    • 1999
  • A biological filter for treatment of toluene among volatile organic compounds was studied. The investigation was conducted using specially built stainless steel columns packed with granular activated carbon and cold for removal of toluene. The G.A. and mold as filter material was also coated with Pseudomonas putida microorganisms.The biofilter unit was operated in the condition of moisture content vairation at gas loading rate of 12.5 l/min. Gaseous toluene taken from tedlar bag was analyzed by the use of G.C equipped with F.I.d detector. The removal efficiency of gaseous toluene was 95% at average inlet concentration of 950 ppm during bio-degradation operating condition. Effective removal efficiency was obtained with moisture content 27.5% at activated carbon and 32% at mold in this study. The effective operating condition were obtained with pH 6-8, temperature 28-42℃ for microbial degradation at gas loading rate of 12.5 l/min in packed material.

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Aeration Factor Used To Design The Container Type of Biopile Systems for Small-Scale Petroleum-Contaminated Soil Projects

  • Jung, Hyun-Gyu
    • Korean Journal of Soil Science and Fertilizer
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    • v.44 no.2
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    • pp.316-319
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    • 2011
  • Biopiles which offer the potential for cost-effective treatment of contaminated soils are above-ground, engineered systems that use oxygen to stimulate the growth and reproduction of aerobic bacteria for degradation of the petroleum constituents adsorbed to soil in excavated soils. This technology involves heaping contaminated soils into piles and stimulating aerobic microbial activity within the soils through the aeration and/or addition of minerals, nutrients, and moisture. Inside the biopile, microbially mediated reactions by blowing or extracting air through the pipes can enhance degradation of the organic contaminants. The influence of a aeration system on the biopile performance was investigated. Air pressure made to compare the efficiency of suction in the pipes showed that there were slightly significant difference between the two piles in the total amount of TPH biodegradation. The normalised degradation rate was, however, considerably higher in the aeration system than in the normal system without aeration, suggesting that the vertical venting method may have improved the efficiency of the biological reactions in the pile.

Biodegradation Characteristics of Nitrogen-containing Aromatic Compounds in Activated Sludge (활성슬러지를 이용한 질소방향족화합물의 생물학적 분해 특성)

  • Jo, Kwan-Hyung
    • Journal of Environmental Health Sciences
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    • v.36 no.3
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    • pp.222-228
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    • 2010
  • Biological degradation of nitrogen-containing aromatic compounds was investigated in activated sludge previously adapted to mineralize low concentrations of nitrogen-containing aromatic compounds. Normally, the time required for 95% degradation of 10 mg/l dinitrophenol (DNP) under aerobic conditions was less than 4 hours without any lag, and with mixed liquor suspended solid (MLSS) levels from 600 to 1,000 mg/l. However, when the initial DNP concentration was increased to 75 mg/l, lags and even complete inhibition of DNP degradation were observed. The length of the lag was found to increase proportionally with decreasing MLSS levels. When dilute activated sludge was incubated for extended periods (192 hours), degradation of 75 mg/l DNP did eventually occur after lag periods of 37 to 144 hours, depending on the MLSS concentration. DNP was degradable in high concentrations if MLSS concentrations were sufficiently high to allow growth of bacteria resistant to the toxic effects of DNP.

The In Vitro Translocation of Escherichia coli Ribose-binding Protein via Various Targeting Routes

  • Lee, Byoung-Chul;Kim, Hyoung-Nan;Hwang, Yong-Il
    • BMB Reports
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    • v.34 no.2
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    • pp.118-122
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    • 2001
  • The translocation of ribose-binding protein (RBP) into the inverted membrane vesicles (IMV) of Escherichia coli and eukaryotic microsomes was studied using the in vitro translation/translocation system. It was found that RBP was translocated into heterologous eukaryotic microsomes co-translationally, as well as post-translationally However, RBP was translocated only past-translationally into IMV. Degradation fragments of RBP with the molar mass of 14 and 16 kDa were produced during the translocation into IMV However, the amount of the degradation products decreased and the mature form of RBP appeared in the presence of phenylmethylsulfonyl fluoride (PMSF). PMSF and GTP accelerated the translocation of RBF It was also found that SecB enhanced the post-translational translocation of RBP It appears that RBP is translocated via at least two targeting paths.

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Degradation of Polyvinyl Alcohol by Brevibacillus laterosporus: metabolic Pathway of Polyvinyl Alcohol to Acetate

  • Lim, Joong-Gyu;Park, Doo-Hyun
    • Journal of Microbiology and Biotechnology
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    • v.11 no.6
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    • pp.928-933
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    • 2001
  • Approximately 0.1 mg/ml of polyvinyl alcohol (PVA) was degraded by the growing cell, Brevibacillus laterospours, for 30 h, and 0.2 mg/ml of PVA was degraded by the cell-free extract that was isolated from Brevibacillus laterosporus. Approximately $0.29{\mu}g$/ml of acetic acid was produced from PVA by using the cell-free extract as a catalyst for 40 min. $V_{max}\;and\;K_m$ value of purified PAV-degradation enzyme was 3.75g/l and 2.75 g/l/min in reaction with EDTA and 3.99 g/l and 2.98 g/l/min in reaction without EDTA, respectively. Molecular weight of the purified enzyme determined by SDS-PAGE was 63,000 Da. Alcohol dehydrogenase and aldehyde dehydrogenase activities were qualitatively detected on a native acrylamide gel by an active staining method, indicating the existence of the metabolic pathway to use PVA as a substrate.

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Autophagy in Neurodegenerative Diseases: From Mechanism to Therapeutic Approach

  • Nah, Jihoon;Yuan, Junying;Jung, Yong-Keun
    • Molecules and Cells
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    • v.38 no.5
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    • pp.381-389
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    • 2015
  • Autophagy is a lysosome-dependent intracellular degradation process that allows recycling of cytoplasmic constituents into bioenergetic and biosynthetic materials for maintenance of homeostasis. Since the function of autophagy is particularly important in various stress conditions, perturbation of autophagy can lead to cellular dysfunction and diseases. Accumulation of abnormal protein aggregates, a common cause of neurodegenerative diseases, can be reduced through autophagic degradation. Recent studies have revealed defects in autophagy in most cases of neurodegenerative disorders. Moreover, deregulated excessive autophagy can also cause neurodegeneration. Thus, healthy activation of autophagy is essential for therapeutic approaches in neurodegenerative diseases and many autophagy-regulating compounds are under development for therapeutic purposes. This review describes the overall role of autophagy in neurodegeneration, focusing on various therapeutic strategies for modulating specific stages of autophagy and on the current status of drug development.

Isolation and Characterization of 2-Methyl-4-Chlorophenoxyacetic Acid-Degrading Bacteria from Agricultural Soils

  • Cho, Seung-Hee;Ka, Jong-Ok
    • Journal of Applied Biological Chemistry
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    • v.42 no.2
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    • pp.57-61
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    • 1999
  • Seven numerically dominant 2-methyl-4-chlorophenoxyacetic acid (MCPA)-degrading bacteria were isolated from agricultural soils. The isolates utilized the herbicide MCPA as a sole carbon source, producing significant biomass in MCPA mineral medium. They exhibited diverse herbicide degradation capabilities, but most of them grew very slowly in mineral medium containing herbicide. The chromosomal DNA patterns of the isolates obtained by polymerase chain reaction amplification of repetitive extragenic palindromic sequences were distinct from each other. One isolate, SH3, which was identified as Sphingomonas species by fatty acid methyl ester analysis, was able to degrade 5 different phenoxyacetic acid herbicides within 4 days. This strain contains two plasmids, and the smaller one has a crucial role in herbicide degradation. MCPA treated into agricultural soils without indigenous MCPA-degraders persisted for a long time, but the application of the isolate SH3 resulted in rapid decline of MCPA concentration in the soil.

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Conservation of Biodiversity and Forest Resources in Nepal -Degradation and Threats-

  • Ghimire, Bimal Kumar;Islam, Mohammad Saiful;Chun, Su-Kyoung
    • Journal of the Korea Furniture Society
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    • v.19 no.4
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    • pp.300-306
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    • 2008
  • Nepal is rich country in terms of its vast array of biological diversity. The relationship between local communities and the biological diversity in Nepal is a very entangle one, whereby two-thirds of our population are heavily dependent upon the biodiversity for their survival. The destruction of biodiversity signifies the destruction of people's livelihoods and survival. Biodiversity and genetic resources conservation has been a most significant part of the Nepalese society due to its socio-economic and cultural importance and provides the human race trees for timber, fuel, food, industrial raw materials, pharmaceuticals, beverages and environmental stabilization. Threats to biodiversity at global level is of greater concern, specially, human activities are the greatest factor currently affecting biodiversity, through the use of natural resources by industry, agriculture, hunting, and energy generation.

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Electro-optical Characteristics of the Degraded Functional Layer in an Alternating- Current Plasma Display Panel

  • Lee, Kyung Ae;Min, Booki;Son, Chang Gil;Byeon, Yong S.;Yoon, Sang Ho;Choi, Eun Ha
    • Applied Science and Convergence Technology
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    • v.24 no.6
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    • pp.232-236
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    • 2015
  • The electro-optical characteristics of several functional layers over the MgO protective layer were studied during the continuous discharge of an AC-PDP. In order to observe the degradation of each functional layer on the MgO protection layer, we measured the surface morphology, cathodoluminescence (CL) spectrum, the secondary electron emission coefficient (${\gamma}$) and the discharge characteristics after 500 hours of discharge during the operation of the AC-PDP.

Service life of concrete culverts repaired with biological sulfate-resisting mortars

  • Hyun-Sub, Yoon;Keun-Hyeok, Yang;Nguyen, Van Tuan;Seung-Jun, Kwon
    • Computers and Concrete
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    • v.30 no.6
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    • pp.409-419
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    • 2022
  • The purpose of this study is to examine the effectiveness of biological repairing mortars on restoring the structural performance of a sewage culvert deteriorated by sulfate attack. The biological mortars were developed for protecting concrete structures exposed to sulfate attack based on the block membrane action of the bacterial glycocalyx. The diffusion coefficient of sulfate ions in the biological mortars was determined from the natural diffusion cell tests. The effect of sulfate-attack-induced concrete deterioration on the structural performance of culverts was examined by using the moment-curvature relationship predicted based on the nonlinear section lamina approach considering the sulfuric-acid-induced degradation of the structure. Typical analytical assessments showed that biological mortars were quite effective in increasing the sulfate-resistant service life of sewage culverts.