Purification and Characterization of Methyl Mercaptan Oxidase from Thiobacillus thioparus for Mercaptan Detection

Lee, Hyun-Ho,Kim, Sang-Joon,Shin, Hyun-Jae,Park, Ji-Yeon,Yang, Ji-Won The Korean Society for Biotechnology and Bioengine 2002 Biotechnology and Bioprocess Engineering Vol.7 No.6

Methyl mercaptan oxidase was successfully induced in Thiobacillus thioparus TK-m using methyl mercaptan gas, and was purified for the detection of mercaptans. The purification procedure Involved a DEAE (diethylaminoethyl) -Sephacel, or Superose 12, column chromatography with recovery yields of 47.5 and 48.5%, and specific activities of 374 and 1240.8 units/mg-protein, respectively, The molecular weight of the purified methyl mercaptan oxidase was 66.1kDa, as determined by SDS-PAGE. The extract, from gel filtration chromatography oxidizes methyl mercaptan, producing formaldehyde, which can be easily detected by the purpald-coloring method. The optimized temperature for activity was found to be at 55$\^{C}$. This enzyme was inhibited by both NH$_4$Cl and (NH$_4$)$_2$SO$_4$, but was unaffected by either KCl or NaCl at less than 200 mM. With K$_2$SO$_4$, the activity decreased at 20 mM, but recovered at 150 mM. In the presence of methanol, full activity was maintained, but decreased in the presence of glycerin, ethanol and acetone 43, 78 and 75%, respectively.

Isolation and Purification of Methyl Mercaptan Oxidase from Rhodococcus rhodochrous for Mercaptan Detection

Kim, Sang-Joon,Shin, Hyun-Jae,Kim, Yeu-Chun,Lee, Dae-Sil,Yang, Ji-Won The Korean Society for Biotechnology and Bioengine 2000 Biotechnology and Bioprocess Engineering Vol.5 No.6

Methyl mercaptan oxidase was successfully induced from Rhodococcus rhodochrous IGTS8 using methyl mercaptan gas and purified to homogeneity for the detection of mercaptans. The purification procedure involved DEAE-Sephacel and Superose 12 column chromatography with recovery yields of 85.8 and 83.3%, and a specific activity of 92.7 and 303.4 units/mg-protein, respectively. The molecular weight of purified methyl mercaptan oxidase was determined to be 64.5 kDa by SDS-PAGE. The extract from gel filtration chromatography oxidizes methyl mercaptan to produce formaldehyde, which can be easily detected by the purpald-coloring method. Optimum temperature for activity was achieved at 60$^{\circ}C$. This enzyme was inhibited by both K$_2$SO$_4$and NaCl at concentration of less than 100mM and recovered to original activity at concentration of 200mM. In the presence of methanol, the activity decreased by 33%.

현미의 산패 억제를 위한 항산화 및 산소제거능 향낭 개발

이정수,한재준 한국포장학회 2015 한국포장학회지 Vol.21 No.1

The objective of this study was to evaluate quality properties including acid value (AV) and peroxide value (POV) of brown rice packaged with antioxidant allyl mercaptan sachet or oxygen scavenging sachet. To prepare the antioxidant allyl mercaptan sachet, allyl mercaptan was encapsulated by rice flour and put in small roll paper pouch. The oxygen scavenging sachet consists of diatomite, sodium L-ascorbate and activated carbon. The results of this study showed that antioxidant allyl mercaptan sachet had no antioxidant effect on deterioration of brown rice, but oxygen scavenging sachet effectively inhibited rancidity of brown rice. Therefore, the developed oxygen scavenging sachet can be effectively utilized in food packaging system for quality stability.

산으로 개질된 활성탄의 메틸 메르캅탄 흡착특성

김대중,김상채,서성규 國立麗水大學校 環境問題硏究所 2004 環境硏究論文集 Vol.6 No.-

Adsorption characteristics of methyl mercaptan on virgin activated carbon(VAC) and modified activated carbons with acidic chemicals have been investigated in the present work. CAC, NAC, AAC and SAC were activated carbons modified with HCl, HNO₃, CH₃COOH and H₂SO₄, respectively. The pore structures and surface characteristics of virgin activated carbon and modified activated carbons were evaluated using nitrogen isotherm, EA, pH of carbon surface and acid value from Boehm titration. respectively. The modification of activated carbon with acidic chemicals resulted in decrease in BET surface area, micropore volume and surface pH, but an increase in acid value. In case of adsorption of methyl mercaptan. The order of the adsorption capacity of activated carbons was NAC>AAC>SAC>CAC>VAC. and in agreement with that of acid value of activated carbons, whereas in disagreement with that of micropore volume of activated carbons. It appeared that chemical adsorption played an important role in methyl mercaptan on modified activated carbons with acidic chemicals compared to virgin activated carbon. These results suggest that the adsorption of methyl mercaptan depends on the surface chemistry rather than the pore structure in modified activated carbons.

Mercaptan계와 Diamine계를 이용한 저수축,절삭력이 우수한 Epoxy Putty의 개발 및 물성에 관한 연구

오승준 ( Seung Jun Oh ),위광철 ( Koang Chul Wi ) 한국접착및계면학회 2015 접착 및 계면 Vol.16 No.4

본 연구에서는 현재 문화재 보존 처리에 사용되고 있는 합성수지를 대체하여 금속, 목재, 도자기, 토기, 석재 유물 등 재질별 문화재 복원 작업에 활용할 수 있는 다목적용 접합, 복원재료인 에폭시퍼티(epoxy putty)를 개발하고자 하였다. 기존에 사용되고 있는 합성수지는 높은 강도로 인한 절삭력의 문제, 긴 경화 시간으로 인한 처짐 현상, 도구나 장갑에 묻어 유물의 표면을 오염시키는 현상, 재료의 황변 현상으로 인한 재처리 등의 문제점을 보이고 있다. 이를 해결하기 위해, 1차적으로 문화재 보존 처리 현장에서 가장 많이 사용되고 있는 페이스트(paste)형태의 복원 재료를 선정하여 물성을 파악한 후이를 비교 대상으로 선택하고, 주제 및 경화제와 충전제의 종류에 따른 에폭시 퍼티를 개발하였다. 개발된 에폭시 퍼티는 기존 재료의 문제점 해결 및 유사한 물성을 지니기 위해 성상(性狀)이 다른 주제와 경화제를 각각 선정하여 물성 실험을 실시하였다. 연구 결과 2종 모두 페이스트 형태로 경화 시간은 5~10min 내외로 기존 재료에 비해 약 3~10배 정도 짧아 작업의 편리성과 처짐 현상을 개선하였으며, 절삭력을 높이기 위한 마모율은 약 3배 정도 향상시켜 쉽게 성형할 수 있도록 하였다. 또한 작업 중 발생하는 표면 오염 등의 단점을 보완하기 위해 충전제로 탈크(talc)와 백색의 micro-balloon을 첨가하여 사용 중손에 묻어 나와 끈적거리는 현상을 줄여주었을 뿐만 아니라 컬러링(coloring), 경량성, 절삭력 등이 높은 저수축, 저황변, 절삭력이 우수한 다목적 복원 재료를 개발하였다. This study aimed to develop epoxy putty as a multi-purpose connection and restoration material that can be used for material-specific restoration work such as metal, wood, ceramics, earthenware and stone artifacts by replacing synthetic resins currently being used for preservation treatment of cultural assets. Existing synthetic resins have the issue of cutting force resulting from high strength, deflection resulting from long hardening time, contaminating the surface of artifacts through staining on tools or gloves and need for re-treatment resulting from material discoloration. Accordingly, paste type restoration material most widely being used in the field of cultural assets preservation treatment was selected and examined the property to select it as an object of comparison. Based on such process, epoxy putty was developed according to the kind of agent, hardener and filler. For the purpose of solving the issues of existing material and allowing the epoxy putty developed to have similar property, property experiments were conducted by selecting agents and hardeners with different characteristics and conditions. The study findings showed that both kinds are paste type that improved work convenience and deflection issue as a result of their work time of within 5~10 minutes that are about 3~10 times shorter than that of existing material. In regards to wear rate for increasing cutting force, it improved by about 3 times, thereby allowing easy molding. For the purpose of improving the issue of surface contamination that occurs during work process, talc and micro-ballon were added as filler to reduce the issue of stickiness and staining on hand. Furthermore, a multi-purpose restoration material with low shrinkage, low discoloration and high cutting force was developed with excellent coloring, lightweight and cutting force features.

Purification and deodorizing activity against methyl mercaptan of polyphenol oxidase from lettuce (Lactuca sativa L.)

이양봉,김선봉,Eui-Cheol Shin 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.12

Polyphenol oxidase (PPO) from lettuce was isolated to determine the effect of its involvement in deodorizingactivity by measuring the reduction in the amount of methyl mercaptan. The enzyme and deodorizing activities of PPOfrom lettuce were evaluated using different substrates, temperatures, and pH levels. The molecular weight of purifiedPPO from lettuce was estimated to be 56 kDa. The PPO and deodorizing activities were highest at the pH range of6.0 at 20 oC and 5.0 at 10 oC, respectively. The deodorizing and PPO activities were greater for ortho-diphenols thanmonophenols and polyphenol. Especially, (+)-catechin, one of ortho-diphenols was shown in 100% PPO activity, andchlorogenic acid and caffeic acid eliminated a methylmercaptan odor up to 95%. The deodorizing activity was highestin Cu2+solution, but ascorbic acid and sodium hydrosulfite inhibited deodorizing activity. These basic data will providean optimum manufacturing condition for commercial products using lettuce extracts.

Template-free hydrothermal synthesis of hollow alumina microspheres and its excellent catalytic properties for thiolation

WeiMing Wang,Shuai Peng,XinTian Chen,YingMing Chen,Chuang Peng,Dong Zeng,Jun Xiong,Hao Liu,XiXian Yang,Ming Li 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.118 No.-

In view of the important industrial application value of alumina supports in the field of oil refining andreforming, it is of great significance to develop a simple and economical synthesis method for the hierarchicalporous alumina. Herein, the hollow microsphere alumina was hydrothermally synthesized withouttemplate. The surface of the hollow microsphere alumina supports has a raised fluffy structure, themicrosphere diameter is about 5 8 lm, and the thickness of the shell is about 1 lm. The morphologyevolution process from solid microspheres to core–shell microspheres with spindle-shaped nanoclusters,and then to hollow fluffy microspheres with protruding surface was observed by investigating the effectof hydrothermal synthesis temperature on the morphology of microspheres. Because of its specific morphologyand surface characteristics, the microsphere can better disperse the active component KW toprepare KW/Al2O3 catalyst and used in the thiolation to methyl mercaptan. Compared with our previouslyused catalysts prepared from commercial alumina, this KW/Al2O3 catalyst was not only able togreatly reduce the amount of active component, but also exhibited higher CH3SH selectivity. On the10KW/Al catalyst, the CH3SH selectivity reached 66.2 % at 340 C, which was about 10 % higher than thatof the previous commercial alumina catalyst. This work can provide theoretical basis and practical guidancefor the reasonable design of new alumina support and high efficiency methyl mercaptan catalyst.

Mercaptan 경화제에 의한 저온속경화 에폭시의 경화거동에 관한 연구

엄세연(Se Yeon Eom),서상범(Sang Bum Seo),이기윤(Kee Yoon Lee) 한국고분자학회 2013 폴리머 Vol.37 No.2

본 연구에서는 DGEBA(diglycidyl ether of bisphenol A)를 사용한 에폭시/mercaptan 경화제의 경화 반응 거동을 에폭시/아민 유도체형 경화제와 비교하여 연구하였다. 경화 반응 거동은 DSC 분석에 의해 승온 및 등온의 조건에서 경화되는 과정을 연구하였다. DSC의 승온 실험에서는 Kissinger 법을 이용하였으며, 등온 실험에서는 Kamal의 속도모델을 이용하여 분석하였다. 결과적으로 활성화 에너지는 아민 유도체형 경화제를 사용하였을 때 약 40 kcal/mol이고, mercaptan 경화제를 사용하였을 때 약 28에서 19 kcal/mol로 -SH 관능기가 증가할수록 감소하였다. 에폭시/아민 유도체형 경화제는 약 90℃ 이상에서 경화 반응이 개시되는 반면, 에폭시/mercaptan 경화제에서는 경화 반응 개시 온도가 약 80℃ 이내로 낮아지고, 반응 속도가 상승하여 반응 시간이 10분 이내로 단축되었다. 또한 에폭시/mercaptan 경화제계는 자기 촉매 반응 모델을 따르는 것을 확인하였고 약 20∼40%의 경화도에서 최대 반응 속도를 나타내었다. The curing behaviors of diglycidyl ether of bisphenol A (DGEBA) with mercaptan hardener were studied by the comparison with amine-adduct type hardener. Curing behaviors were evaluated by DSC at dynamic and isothermal conditions. In the DSC, the dynamic experiments were based on the method of Kissinger`s equation, and the isothermal experiments were fitted to the Kamal`s kinetic model. Activation energy of epoxy/amine-adduct type hardener was ca. 40 kcal/mol. As the functional group of mercaptan hardener, -SH increased, on epoxy/mercaptan hardeners, the activation energies decreased from 28 to 19 kcal/mol. Epoxy/amine-adduct type hardener was initiated at 90℃ or higher. However, epoxy/mercaptan hardeners reduced the initiation temperatures below 80℃ and shortened the durations of curing reaction within 10 min. We found out that the reaction kinetics of epoxy with mercaptan hardener followed the autocatalytic reaction models, and the maximum reaction rates were shown at the conversions of 20∼40%.

Experimental and modeling studies for intensification of mercaptans extraction from LSRN using a microfluidic system

Mohammad Reza Mirani,Alireza Fazlali,Masoud Rahimi 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.5

We investigated the performance of a T-type microchannel for mercaptan extraction from light straightrun naphtha (LSRN) with sodium hydroxide solution. The aim of this work is to introduce the microfluidic system as a potential tool for mercaptan extraction from light petroleum products. Modeling the extraction process of mercaptan from LSRN has not been carried out previously. In this regard, mercaptan extraction was modeled by response surface methodology (RSM) and artificial neural network (ANN) to analyze the effect of operating parameters on the mercaptan extraction process. The independent variables are considered as temperature, sodium hydroxide concentration, and the volume ratio of sodium hydroxide to LSRN. Two models were compared based on error analysis of the predicted data. Root mean square error, mean relative error, and determination coefficient for the neural network were 0.5650, 0.4341, and 0.9862, respectively. The values of these parameters for the RSM model were 0.6854, 0.7648, and 0.9798. The results showed that the prediction accuracy for both models is appropriate, but the precision of the neural network model is slightly higher than that of the RSM model. The genetic algorithm (GA) technique determined the optimal values of the independent variables with the aim of maximizing the extraction percentage. The mercaptan extraction percentage value of 85.08% was achieved at 303.15 K, the sodium hydroxide concentration of 20 wt%, and the volume ratio of sodium hydroxide to LSRN of 0.128. Furthermore, results showed a higher mercaptan extraction percentage of the microfluidic system compared to a conventional extractor at the same process condition.

Mercaptan 경화제에 의한 저온속경화 에폭시의 열적 기계적 물성

이기윤(Kee Yoon Lee),김원영(Won Young Kim),엄세연(Se Yeon Eom),서상범(Sang Bum Seo) 한국고분자학회 2013 폴리머 Vol.37 No.5

본 연구에서는 DGEBA(diglycidyl ether of bisphenol A)와 mercaptan 경화제계의 경화 후 열에 의한 팽창특성과 역학 거동을 에폭시/아민 유도체형 경화제계와 비교하여 연구하였다. 열팽창계수와 역학거동은 각각 TMA (thermo mechanical analysis)와 역학 거동은 DMA(dynamic mechanical ananlysis)를 이용하여 분석하였다. 아민 유도체형 경화제를 사용한 에폭시 경화물의 유리전이온도와 열팽창계수는 각각 82.6 ℃와 71.2 ppm/℃의 값을 나타냈다. Mercaptan 경화제를 사용한 에폭시 경화물의 경우 -SH 관능기가 증가할수록 유리전이온도는 급격히 감소하였다가점차 증가하여 약 80 ℃ 이상의 값을 갖는 경향을 보였고, 유리전이온도 이하에서 열팽창률은 약 80 ppm/℃에서 최대200 ppm/℃까지 증가하였다가 약 100 ppm/℃로 다시 감소하는 경향을 보였다. 아민 유도체형 경화제를 사용한 에폭시 경화물은 약 1.5 mol/cm3의 가교밀도를 나타냈고, mercaptan 경화제를 사용한 에폭시 경화물은 약 1.0 mol/cm3에서 약 1.7 mol/cm3로 관능기가 증가할수록 가교밀도가 증가했다. 또한 30 ℃에서 2700 MPa 이상의 저장 탄성률을가질 수 있음을 확인하였다. The thermal expansion and mechanical properties of diglycidyl ether of bisphenol A (DGEBA) with mercaptan hardeners were studied by a comparative method with an amine-adduct type hardener. Thermal expansion and dynamic mechanical properties were measured by thermo mechanical analysis (TMA) and dynamic mechanical ananlysis (DMA),respectively. The Tg and the coefficient of thermal expansion (CTE) of epoxy/amine-adduct type hardener system were 82.6 ℃ and 71.2 ppm/℃, respectively. As the number of -SH functional group of mercaptan hardener increased, the Tg rapidly decreased and gradually increased up to ca. 80 ℃ and the CTE under the Tg rapidly increased to ca. 200 ppm/℃ from 80 ppm/℃ and decreased to ca. 100 ppm/℃. The crosslinking density of epoxy with amine-adduct type hardener was ca.1.5 mol/cm3, while that of epoxy with mercaptan hardeners increased from 1.0 to 1.7 mol/cm3, as the number of -SH functional group increased. The storage modulus can increase up to 2700MPa at 30 ℃.