• Biotechnology and Bioprocess Engineering:BBE
• /
• v.5 no.6
• /
• pp.465-468
• /
• 2000

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%.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.7 no.6
• /
• pp.375-379
• /
• 2002

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.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.20 no.5
• /
• pp.221-226
• /
• 2010

Quartz crystal microbalance (QCM) gas sensor to detect methyl mercaptan ($CH_3SH$) gas was fabricated by depositing $TiO_2$ nanoparticles and polyelectrolyte on the electrode of QCM. The $TiO_2$/poly(sodium 4-styrenesulfonate) (PSS) thin film fabricated by a layer-by-layer self-assembly (LBL-SA) method showed a high surface area and increased the sensitivity of gas sensor. When the QCM sensors coated with triethanolamine (TEA) or ($TiO_2$/PSS) were exposed to methyl mercaptan gas (1.0 ppm), the frequency shifts of QCM with TEA casting film and $TiO_2$/PSS thin film were ca. 9 Hz and ca. 24 Hz, respectively. As the bilayer number of ($TiO_2$/PSS) increased, the frequency shift of QCM sensor with ($TiO_2$/PSS) thin film was gradually increased. In addition, the frequency shift of QCM sensor was gradually increased as the concentration of methyl mercaptan gas increased from 0.5 ppm to 2.0 ppm. In this study, the surface morphology and sensor property of QCM sensor coated with ($TiO_2$/PSS) thin film were measured.

• Journal of Korean society of Dental Hygiene
• /
• v.11 no.2
• /
• pp.263-275
• /
• 2011

Objectives : This study was performed analysis of Halitosis components following by subjective cognition of halitosis and Oral State in order to provide basic data for halitosis prevention and establish a device to efficiently eliminate halitosis and analyze the factors that affect the halitosis. Methods : 80 adults were participated who visited at the Dental Clinic in Kyoung-gi do, on the period of the March to September in 2010. The obtained results, through the oral examination, halitosis check and interview, Individually, were as followings. Results : According to the ammonia level was a high relationship between sex, CPI, Tongue plaque, DMFT index which were statistically significant (p<0.05). Total oral gas level was a relationship between VAS, tongue plaque, DMFT index(p<0.05). The Correlation coefficient between the Hydrogen sulfide level and Methyl mercaptan was estimated as r=0.534(p<0.01). As for the multiple regression analysis result, there have been selected dimethyl sulfide and Tongue plaque, Gingival index as factors affecting Bridge, Methyl mercaptan level is as factors affecting Hydrogen sulfide level. Conclusions : There was relationship between the periodontal disease and Ammonia gas component, hydrogen sulfide, dimethyl sulfide, methyl mercaptan. Which were statistically significant total oral gas level and oral variables. Such dental caries as the prevention or early treatment of periodontal disease.

• Journal of Korean Society for Atmospheric Environment
• /
• v.18 no.E3
• /
• pp.165-174
• /
• 2002

A dual -column biofilter system with two different composts was used to investigate the macro-kinetics of dim-ethyl disulfide (DMDS) degradation. The biofilter columns were filled with compost mixtures up to one meter, The gas How rate and DMDS concentration to the biofilters were varied to study their effect on the removal characteris-tics of DMDS. It was found that the biodegradation of DMDS was governed by zero-order reaction -limited macro-kinetics for inlet DMDS concentrations between 10 and 55 ppmv. The overall average zero-order kinetic coeffi-cient for DMDS removal by compost was 0.50 ($\pm$0.1) ppm/sec for both compost mixtures studied. Variations in individual kinetic coefficients were observed due to varying environmental conditions, such as pH and temperature. The kinetic coefficients determined are specific to the system discussed in this work. During high acidity conditions in the filter beds, methyl mercaptan (MM) was observed in the gas samples collected. Appearance of MM was pro-bably due to decreased microbial activity in the lower portions of the biofilter. Considering the neutral pH range required and the presence of methyl mercaptan, it is likely that the microorganisms present in the biofilters used in this research are similar to the T. thioparus (strain E6) species.

• Journal of Environmental Science International
• /
• v.16 no.1
• /
• pp.33-38
• /
• 2007

The concentrations of offensive odorous compounds emitted from the two chemical plants in Chongju and Yeosu industrial complex in Korea were determined by uv/vis spectroscopy, gas chromatography, and high performance liquid chromatography. The odorous compounds examined in this study are ammonia, trimethyl amine, formaldehyde, acetaldehyde, propion aldehyde, butyl aldehyde, n-valeric aldehyde, iso-valeric aldehyde, hydrogen sulfide, methyl mercaptan, dimethyl sulfide and dimethyl disulfide. The concentrations of those were determined from the 10 sampling points of the two plants, respectively. The emission concentrations of all odorous com-pounds examined in the two plants were lower than those of the regulation standard levels of industrial complex in Korea, respectively. The propion aldehyde, n-valeric aldehyde, methyl mercaptan and dimethyl disulfide in Chongju and Yeosu plants, and butyl aldehyde and iso-valeric aldehyde in Yeosu plant were not detected at any sampling points examined.

• KSBB Journal
• /
• v.22 no.3
• /
• pp.151-156
• /
• 2007

Increasing public concerns over odors and air regulations necessitates the remediation of a wide range of odorous compounds for industrial purpose. Currently, wet scrubbing technique by neutralization using essential oils is utilized to treat methyl mercaptan odor. The chemical analysis is performed to analyze the composition of an essential oil by GC-MS. The objective of this study is to clarify the possibility of the neutralization of odors sprayed in the fixed bed and determine the removal efficiencies in the misty aerosol by different input odor concentration. It is found that methyl mercaptan is significantly removed in the wet scrubber, and their removal efficiency of methyl mercaptan is obtained by 98%.

• Korean Journal of Food Science and Technology
• /
• v.34 no.4
• /
• pp.559-564
• /
• 2002

Volatile odor components of ripened and ripened/freeze-dried kimchi were analyzed by gas chromatograph. As ripening temperature of kimchi increased, pH of kimchi decreased, viable cell count of lactic acid bacteria of kimchi increased up to ripening temperature of $15^{\circ}C$, and sensory properties of kimchi gradually decreased. Allyl mercaptan, methyl allyl sulfide, dimethyl disulfide, diallyl sulfide, diallyl disulfide, and ethanol were detected in ripened kimchi and ripened/freeze-dried kimchi. The amounts of allyl mercaptan, methyl allyl sulfide, diallyl sulfide, and ethanol increased as the ripening temperature increased, while those of dimethyl disulfide and diallyl disulfide decreased. Freeze-drying for 24 hr removed most of the above-mentioned volatile odor components, which were further removed by freeze-drying for 48 hr.

• Journal of environmental and Sanitary engineering
• /
• v.22 no.2
• /
• pp.35-40
• /
• 2007

It disposes positively in the air pollution damage which is serious, in order help period the place where it improves the quality of existence and life of the local residents. It removed the offensive odor regulation material and the technique it will be able to prevent to sleep it researched it did. After scattering the GNC solution which develops the offensive odor regulation material which occurs from the food and trash treatment plant which is located to the S from the H, company after scattering the GNC solution which it develops collection it did a control criminal record control kind air and it analyzed. In this study, we investigated the emission concentrations of offensive odorous compounds of hydrogen sulfide, methyl mercaptan, dimethyl sulfide and dimethyl disulfide, trimethylamine, formaldehyde, acetaldehyde, propionaldehyde, buthylaldehyde, iso-valeric aldehyde, n-valeric aldehyde, ammonia. The concentrations of odorous compounds are determined by gas chromatography, HPLC and uv-vis spectroscopy. Hydrogen sulfide, methyl mercaptan, dimethyl sulfide and dimethyl disulfide were not detected at any point examined.

• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.8
• /
• pp.541-548
• /
• 2012

The objective of this study was to investigate emission characteristics of odorous compounds from the pneumatic waste collection plants (namely, A and B sites). The air samples were collected from each site, at a carrier gas inside the plant and an exhaust gas, to analyze complex odor and 22 odorous compounds. Ammonia, sulfur compounds, and acetaldehyde were the critical odorous components generated in the plants studied. Characteristics of odor at exhaust outlet varied according to the type of odor control engineering. In the analysis of the odor contribution degree of odor components based on odor threshold, site A shows that the odor contribution of dimethyl sulfide was found to be 26%, acetaldehyde 18%, and methyl mercaptan 14%. For site B, methyl mercaptan was 56% and both hydrogen sulfide and dimethyl sulfide were 15%.