• Journal of Microbiology and Biotechnology
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• 제33권1호
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• pp.1-14
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• 2023

Polyethylene terephthalate (PET) is a plastic material commonly applied to beverage packaging used in everyday life. Owing to PET's versatility and ease of use, its consumption has continuously increased, resulting in considerable waste generation. Several physical and chemical recycling processes have been developed to address this problem. Recently, biological upcycling is being actively studied and has come to be regarded as a powerful technology for overcoming the economic issues associated with conventional recycling methods. For upcycling, PET should be degraded into small molecules, such as terephthalic acid and ethylene glycol, which are utilized as substrates for bioconversion, through various degradation processes, including gasification, pyrolysis, and chemical/biological depolymerization. Furthermore, biological upcycling methods have been applied to biosynthesize value-added chemicals, such as adipic acid, muconic acid, catechol, vanillin, and glycolic acid. In this review, we introduce and discuss various degradation methods that yield substrates for bioconversion and biological upcycling processes to produce value-added biochemicals. These technologies encourage a circular economy, which reduces the amount of waste released into the environment.

• Journal of Applied Biological Chemistry
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• 제49권3호
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• pp.101-105
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• 2006

Degradation of the herbicide butachlor was investigated using laboratory-synthesized zerovalent iron ($Fe^0$). The synthesized zerovalent iron was determined to be nanoscale powder by scanning electron microscopic analysis. To investigate degradation of butachlor using the synthesized nanoscale zerovalent iron, time-course batch experiments were conducted by treating the solution of butachlor formulation with the iron. More than 90% degradation of butachlor was observed by iron treatment within 24 h. The synthesized nanoscale zerovalent iron showed an increase in particle aggregation in the batch tests. Green rust formation and a pH drop in solutions were observed, suggesting that the oxidation of the iron occurred. When the iron was extracted with dichloromethane, a negligible concentration was found in the extract, suggesting that butachlor did not bind to the iron particles. GC/MS analysis detected the dechlorinated product as a major degradation product of butachlor in the solutions. The data indicate that laboratory-synthesized zerovalent iron functioned as a reductant to remove electron-withdrawing chlorine, giving the dechlorinated product.

• Journal of Applied Biological Chemistry
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• 제50권4호
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• pp.281-287
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• 2007

Microorganisms were isolated from earthworm intestine and examined for their ability to degrade 3-methyl-4-nitrophenol (MNP), a main degradation product of the insecticide fenitrothion. An isolate that showed the best degradation of MNP was selected for further study. The 16S rRNA analysis showed that the isolate belongs to the genus of Burkholderia, close to phenanthrene-degrading Burkholderia sp. S4.9, and is named Burkholderia sp. SH-1. When time-course degradation of MNP by SH-1 was examined by high performance liquid chromatographic analysis, almost complete degradation of MNP was observed within 26 h. Colony forming unit value assays indicated that the isolate SH-1 was capable of utilizing MNP as a sole carbon source. SH-1 could also degrade p-nitrophenol (PNP) but could not degrade ortho-substituted nitroaromatics such as 2,4-, 2,6- and 2,5-dinitrophenol. Catechol was detected as the main degration product of MNP and PNP. SH-1 was also found in the soil from which earthworms were obtained. These results suggest that the dispersal of Burkholderia sp. SH-1 into different environment with the aid of earthworms is likely to play a role in bioremediation of the soil contaminated with MNP.

• Applied Biological Chemistry
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• 제40권6호
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• pp.519-524
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• 1997

우렁쉥이 껍질로부터 추출한 카로테노이드 색소의 식품첨가물로서의 이용 가능성을 알아보기 위하여 SDE(simultaneous distillation and extraction/concentration) 장치를 이용하여 휘발성 화합물을 추출하였다. 이를 GC 및 GC-MS로 분석하여 총 63성분의 휘발성 화합물을 동정하였고, 대부분의 화합물이 카로테노이드의 가열분해로 생성되어지는 것으로 나타났다. 동정된 화합물중 대표적인 화합물은 1,3,5-trimethylbenzene, 3,5,5-trimethyl-3-cyclohexen-1-ol, 3,5,5-trimethyl-3-cyclohexen-1-one, 1,1,2,3-tetramethyl-2-cyclohexen-5-ol, 1,1,2,3-tetramethyl-2-cyclohexen-5-one, 2,3,4,4-tetramethyl-6-hydroxy-2-cyclohexene-1-one, 1,2,3,8-tetrahydro-3,3,6-trimethyl-1-naphtol, dihydroacetinidolide, ${\beta}-ionone$, 2-(1,1,5-trimethyl-3-hydroxy-5-cyclohexen-6-yl)-1-to-lylethene, 2,6-dimethyl-8-(1,1,5-trimethyl-3-hydroxy-5-cyclohexen-6-yl)-1,3,5-octatriene-7-yne 등 이었다. 이중 몇가지 화합물의 생성기작도 추정해 보았다.

• Applied Biological Chemistry
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• 제33권2호
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• pp.138-142
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• 1990

담수토양중(湛水土壤中) 살균제(殺菌劑) IBP, 살충제(殺蟲劑) fenitrthion, 살초제(殺草劑) butachlor의 분해(分解)에 미치는 각종중금속(各種重金屬) Cd, Cu, Cr, Ni, Zn의 영향(影響)에 대하여 연구검토(硏究檢討)하였다. 토양중(土壤中) 3농약(農藥)의 분해(分解)는 5종(種)의 중금속첨가(重金屬添加)에 의하여 현저히 억제(抑制)되었으며, 억제(抑制)된 정도(程度)는 butachlor>IBP>fenitrothion순(順)이었다. MPN법에 의하여 계측(計測)한 fenitrothion과 butachlor 분해균(分解菌)의 균수(菌數)은 중금속(重金屬) 첨가(添加) 토양(土壤)에서가 무첨가토양(無添加土壤)에서보다 적었다. 토양중(土壤中) 3농약(農藥)의 분해(分解)에 미치는 영향정도(影響程度)는 중금속(重金屬)의 종류(種類) 및 농도(濃度), 농약(農藥)의 종류(種類)에 따라 현저한 차이(差異)를 나타내어, fenitrothion의 분해(分解)를 Cr>Zn>Cd>Ni>Cu순(順)으로 억제(抑制)시켰다. IBP의 분해(分解)는 $Cr>Cu{\geqq}Zn{\geqq}Cu$순(順)으로 억제(抑制)받았으나, Ni는 분해(分解)에 거의 영향(影響)을 주지 않았다. 그리고 butachlor의 분해(分解)는 Cr>Cu>Cd>Ni>Zn순(順)으로 억제(抑制)되었다.

• Applied Biological Chemistry
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• 제33권2호
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• pp.125-128
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• 1990

저온에서 완두유묘 줄기의 유리 IAA 수준과 그 전구체인 트립토판 수준이 저하하므로, IAA수준의 조절 메커니즘을 규명하기 위하여 IAA분해효소계에 미치는 저온의 영향을 조사하였다. $25^{\circ}C$에서 키운 백색 관두유표를 $5^{\circ}C$의 저온으로 옮기면 IAA oxidase와 peroxidase의 수준은 증가하였으며 catalase의 수준은 저하되었고 과산화수소는 축적되어, 전체적으로 IAA분해계가 저온에서 강화되었다. 저온에 놓였던 유묘를 상온으로 옮기면 IAA 분해계는 다시 대조구 수준으로 회복하였다.

• Applied Biological Chemistry
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• 제31권2호
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• pp.200-204
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• 1988

토양중(土壤中)에 있어서 제초제(除草劑) pretilachlor의 분해성(分解性)에 미치는 토성(土性), 유기물함량(有機物含量), 온도(溫度), 수분상태(水分狀態)의 영향(影響)에 대하여 연구(硏究)하였다. 토양중(土壤中) pretilachlor의 잔효기간(殘?期間)은 60g a.i./10a 처리수준(處理水準)에서 약(約) 50일(日)였으며, 피에 대하여 GR 50치(値)까지 달하는 기간(期間)은 약(約) $25{\sim}27$일(日)이었다. pretilachlor의 분해속도(分解速度)는 사양토(砂壤土)에서 보다 유기물(有機物)과 점토(粘土)의 함량(含量)이 높았든 사질식양토(砂質植壤土)에서 빨랐다. 토양중(土壤中) pretilachlor의 분해(分解)는 유기물첨가(有機物添加)에 의하여 촉진(促進)되였으며, $20^{\circ}C$에서 보다 $30^{\circ}C$에서, 습윤조건하(濕潤條件下)에서보다 담수조건하(湛水條件下)에서 빨랐다.

• Journal of Microbiology and Biotechnology
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• 제15권6호
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• pp.1207-1213
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• 2005

In a search for bacteria capable of degrading styrene better than previously isolated strains, bacterium IS-3 was isolated from activated sludge and found to be most closely related to Pseudomonas sp. Styrene degradation by this strain was tested in liquid cultures and polyurethane-packed biofilters. In liquid cultures, the rate of styrene degradation by this bacterium increased from 24.93 to $76.53\;{\mu}mol\;g^{-1}\;DCW\;H^{-1}$ for an initial mass range from 8.7 to $34.8{\mu}mol$. The maximum styrene elimination capacity was 580-635 $g/m^{3}\cdot$h at a space velocity (SV) of 50-200/h. The critical elimination capacities guaranteeing $95\%$ removal of the input styrene were determined to be 635, 170, and 38 $g/m^{3}\cdot$h, respectively, at SVs of 50, 100, and 200/h. Kinetic analysis revealed that the maximum styrene elimination velocity ($V_{m}$) for this biofilter was 1,000 g/m$\cdot$h, and the saturation constant ($K_{m}$) was 454 ppmv. Together, these results suggest that a polyurethane biofilter containing Pseudomonas sp. IS-3 could have potential practical applications for the effective removal of styrene gas.

• Applied Biological Chemistry
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• 제25권3호
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• pp.126-134
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• 1982

$^{14}C-2$, 6-Diethylaniline을 토양중에서 호기적으로 21 주간 배양시 발생된 $^{14}CO_2$는 살균하지 않은 A토양(clay loam)과 B토양(coarse sandy loam)에서 각각 6.5%와 10.1%이었다. Methanol로 토양을 추출시 A토양에서는 3.1%, B토양에서는 13.5%의 토양방사능이 추출되었다. 토양중에서의 분해산물은 2, 6-diethylacetanilide 이었으며 Chaetomium globosum은 순수배양시 분해산물로 2, 6-diethyl-p-benzoquinone을 생성하였고 이의 생성경로는 2, 6-DEA의 p-hydroxylation, quinoneimine의 형성 그리고 암모니아 발생을 수반하는 가수분해 등으로 제안하였다.

• 공업화학
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• 제24권5호
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• pp.518-524
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• 2013

본 연구에서는 유전체 배리어 방전 플라즈마를 이용한 상수원의 이취미 및 독성물질 분해에 대하여 조사하였다. 이취미 물질로 지오스민(geosmin)과 2-methyl isoborneol (2-MIB)을 사용하였고, 독성물질로는 microcystin-LR (MC-LR), microcystin-RR (MC-RR), microcystin-YR (MC-YR), 그리고 anatoxin-a를 사용하였다. 플라즈마 반응기의 유입기체에 따른 분해 효율(반응시간 150 s 기준)은 지오스민의 경우 산소(100%) > 건조공기(96%) > 질소(5%) 순이었으며, 2-MIB의 경우에도 산소(100%) > 건조공기(94%) > 질소(2%) 순이었다. 이 결과는 이취미 물질이 주로 플라즈마 방전에 의해 생성된 산화성 성분, 특히 수명이 긴 오존에 의해 분해된다는 것을 나타낸다. 산소를 사용했을 때 지오스민과 2-MIB는 150 s 이내, microcystin류는 10 s 이내, anatoxin-a는 30 s 이내에 모두 분해되었다. 실제 호소수를 사용한 경우 증류수에서보다 이취미 및 독성물질의 분해효율보다 높게 나타났다.