• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.303-311
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• 2000

This study was conducted to find an optimal TNT transformation condition with the addition of different carbon and energy sources in a batch reactor. When TNT and nitrate were present in the medium, the cell growth and TNT transformation was slower because nitrate and TNT was competitively served as electron acceptor. Transformation of TNT was faster when TNT in the medium was nitrogen source and acetate as a carbon source. Cell growth and nitrate transformation was slower when yeast extract was not present in the medium. The proposed intermediates of TNT biotransformation from the earlier studies was not detected in this experiment but the intermediates are tentatively proposed as nitro and amino-free compounds. These results should be helpful for the operation of the munition waste treatment in the future.

• Applied Biological Chemistry
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• v.35 no.4
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• pp.242-247
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• 1992

Twenty strains of pentachlorophnol (PCP) resistant bacteria were isolated from activated sludge of the sewage treatment plant of Jung Lang Chun, Seoul. The predominant strains were Bacillus spp. including B. sphaericus and E. schlegelii. The other strains were identified as Corynebacterium spp., Staphylococcus aureus, Arthrobacter spp. and Aeromonas spp. The resistant strains could be grouped into two categories; PCP-degrading and PCP-adsorbing/absorbing ones. PCP-degrading strains degraded $75{\sim}90%$ of PCP in the medium containing 100 ppm PCP during the first 24 hours of growth. At the initial period the PCP-adsorbing/absorbing strains removed PCP from the medium but started to release PCP after 24 or 72 hours of growth. PCP degradation products from the culture broth of PCP-degrading strains were identified by comparing their $R_f$ values with those of the reference compounds. 2-chlorophenol and 2.4-dichlorophenol were presumed to be the intermediate products of PCP degradation.

• Korean Journal of Microbiology
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• v.37 no.1
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• pp.66-71
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• 2001

An aerobic microbiological process was tested in 1.5 L stirred tank reactors for the treatment of dinitrotoluenes (DNTs)[e.g., 2.4-dinitrotoluene (2,4-DNT), 2,6-dinitrotoluene (2,6-DNT)] in the test culture of Stenotrophomonas maltophilia, which had previously characterized. Both 2,4-DNT and 2,6-DNT were completely degraded within 10 days and 14 days of incubation, respectively. Addition of the secondary carbon was essential to degrade DNTs, and little degradation was achieved in the absence of the secondary carbons. The effect of additional nitrogens on the degradation of DNTs was evaluated. Complete degradation of DNTs was observed in the absence of any additional nitrogens, whereas DNTs were partially degraded in the growth media with additional nitrogens. Both HPLC and GC-MS were used to detect and verify the residual DNTs and their intermediates. As the results, the HPLC and GC-MS chromatograms demonstrated that the both parent compounds, 2, 4-DNT and 2,6-DNT, and respective intermediates, 2-amino-4-nitrotoluene and 2-amino-6-nitrotoluene, could be successfully identified under the analytical conditions.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.159-160
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• 2015

본 연구에서는 구리 도금액 구동 과정에서 SPS의 분해와 분해 산물의 영향에 대해 고찰하였고 이를 실시간으로 관찰하기 위한 전기화학적 모니터링법을 제시하였다.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.826-837
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• 2015

In this study, we produced bioethanol from the original hydrolysate obtained during oxalic acid pretreatment of lignocellulosic biomass. The bioethanol was separated and concentrated by pervaporation and the residue after pervaporation was evaluated for its antioxidant activity. Xylose ($37.28g/{\ell}$) was the major product in the original hydrolysate. The original hydrolysate contained acetic acid, furfural and total phenolic compounds (TPC) as fermentation inhibitors. Acetic acid was removed by electrodialysis (ED), and $12.21g/{\ell}$ of bioethanol was produced from ED-treated hydrolysate. The TPC of ethyl acetate extracts from the residue obtained (OA-E) during pervaporation was 86.81 mg/100 g (extract). The $IC_{50}$ values of DPPH and ABTS radical scavenging activities, and reducing power of OA-E were $0.87mg/m{\ell}$, $0.85mg/m{\ell}$, and $0.59mg/m{\ell}$, respectively. Sugar degradation products and the phenolic compounds in OA-E were determined by GC-MS.

• Korean Journal of Environmental Agriculture
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• v.19 no.4
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• pp.300-308
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• 2000

The degradation of herbicide $^{14}C-bifenox$ was studied in soils under anaerobic conditions. $^{14}C-bifenox$ was treated in silty loam and sandy loam soils, respectively at a rate of 2.1 mg/kg, and the soil was incubated under anaerobic conditions at $25^{\circ}C$ for 180 days. The mineralization, solvent extractable and non-extractable residues, degradation products of bifenox were investigated during the experiments. The relative amounts of $^{14}CO_2$ were 1.97 and 0.9% of applied $^{14}C$ in silty loam and sandy loam soils, respectively. The non-extractable residues of sandy loam soil increased dramatically up to 79.12% of applied $^{14}C$, and were higher than those of silt loam soil, suggesting physico-chemical properties and especially organic matter contributed to the difference of $^{14}C$ between two soils. The non-extractable residues were formed mainly humin fraction and increased with time. The major metabolites were nitrofen, 5-(2,4-dichlorophenoxy)-2-Nitrobenzoate, 2,4-dichlorophenoxy aniline and methyl 5-(2,4-dichlorophenoxy) anthranilate by GC/MS analysis. From the results of volatilization, mineralization and degradation of bifenox, bifenox was stable chemically and biologically in soil.

• Applied Biological Chemistry
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• v.34 no.4
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• pp.299-306
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• 1991

When $[U-^{14}C]$ 3,3', 4,4'-tetrachloroazobenzene$([U-^{14}C]\;TCAB)$ was added to the $MM_2$ medium as a sole carbon source for the isolated microorganisms and incubated, some radioactive metabolites were detected by autoradiography. No $^{14}CO_2$ was evolved from $[U-^{14}C]\;TCAB$ which was added as a sole carbon source to an organic matter-free soil inoculated by the isolates, wetted with the $MM_2$ salt medium, and incubated at $30^{\circ}C$. One of the metabolites in pure culture of Achromobacter group VD, which was isolated and identified, was tentatively identified as a compound of m/z 250 by means of GC/MS. The possible pathways for its formation are thought to include dechlorination from the TCAB structure, hydroxylation, ortho fission of the two benzene rings, and reduction of the resulting carboxyl group.

• Journal of Life Science
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• v.18 no.1
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• pp.103-108
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• 2008

An agar-degrading marine bacterium, strain AS-1 was isolated from the seawater. The strain AS-1 was identified as Sphingomonas paucimobilis (90% probability) by VITEK. The optimum medium for agarase activity of the isolated strain was determined to be marine medium, marine broth 2216 containing 0.1% agar as carbon source. An extracellular agarase was purified 104-fold from the culture supernatant by ammonium sulfate precipitation, ion exchange chromatography and gel filtration methods. The molecular weight of the purified enzyme was estimated to be 80 kDa by SDS-PAGE. The optimum pH and temperature for activity were 7.0 and $40^{\circ}C$, respectively. Antioxidative activity of the strain AS- was 72% in the supernatant cultured for 12 h. The culture supernatant of the strain AS-1 showed antibacterial activity against bacteria causing putrefaction and food poisoning such as Escherichia coli, Staphylococcus aureus and Proteus vulgaris. However, the cell growth of the lactic aicd forming strain, Lactobacillus plantarium was promoted by the treatment of 10% culture supernatant of an agar-degrading strain.

• Current Research on Agriculture and Life Sciences
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• v.5
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• pp.27-32
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• 1987

To isolate and identify degradation products of propanil in solution which propanil concentration was 2000ppm with a certain temperature, degradation products and pathway were investigated every 2 weeks for 12 weeks. Extracted mixture was developed with benzene on TLC plate, and Rf values of isolated DCA and TCAB were 0.65 and 0.94 respectively. At the GC analysis, propanil and its degradation products could seperate at the column temperature $200^{\circ}C$, but in order to more good resolution, the column temperature of DCA and TCAB was $140^{\circ}C$ and $250^{\circ}C$ respectively. Functional group of OCA was determined by IR spectrum $3400cm^{-1}$ and $800cm^{-1}$. Proton peaks of OCA were NMR spectrum $6.7{\delta}$ and $3.7{\delta}$. As the results, the major degradation products of propanil in solution were seperated on TLC plate, and thus identified by the analysis of GC, IR and NMR. Proposed degradation pathway of propanil in solution was from DCA to TCAB.

• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.26-30
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• 2000

Degradabilities of the dicamba by microorganisms isolated from soil and by enzymes in the turfgrass, Zoysia Japonica S. were investigated. Five species of dicamba-deading microorganisms including Acidovorax sp., Alcaligenes sp., and Variovorax sp. were isolated from soils by enrichment culture. All strains in nutrient-free inorganic medium treated with 10 ppm of dicamba degraded average 90% of the dicamba 21 days after incubation. 5-Hydroxydicamba, major metabolite, was detected from the culture broth. The half life of dicamba in the phosphate buffer extracts of Zoysia Japonica S. was 2.5 to 2.7 days. Trace amounts of 4- and 5-hydroxydicamba were detected in the extracts.