[Investigations on atmospheric pollution in the city of Milan. I. Methods for the determination of sulfur compounds (sulfur dioxide, hydrogen sulfide, etc)].
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Air Pollution↗
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Results for “Sulfur Compounds”
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Discrimination between 34S and 32S during bacterial metabolism of inorganic sulfur compounds.
Sulfur isotope effects during the oxidation of thiosulfate by Thiobacillus versutus were found to be negligible. This result is considered in relation to other oxidative and reductive processes to assess which reactions are most likely to control the isotopic compositions of sulfur compounds in microbial sulfureta.
Oxidation-Reduction↗
Production of carbonyl compounds and sulfur compounds on irradiation of amino acids.
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Amino Acids↗
Development and validation of a plate technique for screening of microorganisms that produce volatile sulfur compounds.
Volatile sulfur compounds (VSCs) are of major importance for flavor development in foodstuffs such as cheeses. Such compounds originate from the amino acid l-methionine, which can be degraded to methanethiol (MTL), a common precursor to a variety of other VSCs. A plate assay based on double-layer petri dishes containing 5,5'-dithio-bis-2-nitrobenzoic acid (DTNB), a chemical used for the estimation of free thiols, in the upper layer provides an easy and reliable detection method for thiol-producing, cheese-ripening microorganisms. MTL production was quantitated by measuring the yellow-orange color intensity resulting from reaction with DTNB. Using this method, 18 Geotrichum candidum strains isolated from cheeses were compared, and the color intensity was found to be correlated with the production of microbial VSCs as measured by gas chromatographic analysis.
Cheese↗
Microbial desulfurization of organic sulfur compounds in petroleum.
Sulfur removal from petroleum is important from the standpoint of the global environment because the combustion of sulfur compounds leads to the production of sulfur oxides, which are the source of acid rain. As the regulations for sulfur in fuels become more stringent, the existing chemical desulfurizations are coming inadequate for the "deeper desulfurization" to produce lower-sulfur fuels without new and innovative processes. Biodesulfurization is rising as one of the candidates. Several microorganisms were found to desulfurize dibenzothiophene (DBT), a representative of the organic sulfur compounds in petroleum, forming a sulfur-free compound, 2-hydroxybiphenyl. They are promising as biocatalysts in the microbial desulfurization of petroleum because without assimilation of the carbon content, they remove only sulfur from the heterocyclic compounds which is refractory to conventional chemical desulfurization. Both enzymological and molecular genetic studies are now in progress for the purpose of obtaining improved desulfurization activity of organisms. The genes involved in the sulfur-specific DBT desulfurization were identified and the corresponding enzymes have been investigated. From the practical point of view, it has been proved that the microbial desulfurization proceeds in the presence of high concentrations of hydrocarbons, and more complicated DBT analogs are also desulfurized by the microorganisms. This review outlines the progress in the studies of the microbial desulfurization from the basic and practical point of view.
Biodegradation, Environmental↗
The effect of an oral hygiene program on oral levels of volatile sulfur compounds (VSC).
Volatile sulfur compounds (VSCs) produced by bacteria in niches of the oral cavity play a major role in the etiology of bad breath, and can be easily detected by a portable sulfide monitor (Halimeter). To investigate the effect of an oral hygiene program on VSC levels, Halimeter readings were taken from 55 healthy dental students during a course in oral hygiene training, including instruction on brushing, flossing and professional tooth cleaning. Ten students who received no oral hygiene training served as a negative control. The oral hygiene status was measured using the papillary bleeding index (PBI). PBI and VSC values did not show significant changes during the study period of 10 weeks in the control group. In the test group, PBI values significantly decreased compared to baseline and the control, indicating that the oral hygiene program had a benefit on the oral hygiene status. The VSC values also decreased significantly during the study period compared to baseline and the control. It was concluded that in a group of dental students, a thorough oral hygiene training program was capable of reducing the oral level of VSC Halimeter readings.
Adult↗
Effects of inhibitors and NaCl on the oxidation of reduced inorganic sulfur compounds by a marine acidophilic, sulfur-oxidizing bacterium, Acidithiobacillus thiooxidans strain SH.
The effect of NaCl and the pathways of the oxidation of reduced inorganic sulfur compounds were studied using resting cells and cell-free extracts of Acidithiobacillus thiooxidans strain SH. This isolate specifically requires NaCl for growth. The oxidation of sulfur and sulfite by resting cells was strongly inhibited by 2-heptyl-4-hydroxyquinoline-N-oxide. Carbonylcyanide m-chlorophenyl-hydrazone and monensin were also relatively strong inhibitors. Thiosulfate-oxidizing activity was not inhibited by these uncouplers. Valinomycin did not inhibit the oxidation of sulfur compounds. NaCl stimulated the sulfur- and sulfite-oxidizing activities in resting cells but not in cell-free extracts. The tetrathionate-oxidizing activity in resting cells was slightly stimulated by NaCl, whereas it did not influence the thiosulfate-oxidizing activity. Sulfide oxidation was biphasic, suggesting the formation of intermediate sulfur. The initial phase of sulfide oxidation was not affected by NaCl, whereas the subsequent oxidation of sulfur in the second phase was Na+-dependent. A model is proposed for the role of NaCl in the metabolism of reduced sulfur compounds in A. thiooxidans strain SH.
Acidithiobacillus thiooxidans↗
Toxicology of thiono-sulfur compounds.
Thiono-sulfur-containing compounds cause a wide variety of toxic effects in mammals. These toxic effects of thiono-sulfur-containing compounds appear to be at least partially the result of their metabolism to reactive intermediates by the cytochrome P-450-containing monooxygenase enzyme systems. Covalent binding of (atomic) sulfur released in the cytochrome P-450 monooxygenase catalyzed metabolism of certain thiono-sulfur compounds appears to be responsible for the inhibition of monooxygenase activity and the loss of cytochrome P-450 seen on administration of these thiono-sulfur compounds in vivo or incubation with cytochrome P-450 monooxygenase enzymes in vitro. Liver necrosis and perhaps the induction of lung edema and neoplasia as well as other effects of thiono-sulfur-containing compounds are more likely the result of the covalent binding of the electrophilic S-oxides or S-dioxides or carbene derivatives of these S-oxides and S-dioxides to tissue macromolecules. The rationale for implicating metabolites of thiono-sulfur compounds other than atomic sulfur in these effects derives from the experiments with thioacetamide and the fact that atomic sulfur is highly reactive and appears to bind predominantly or exclusively to cytochrome P-450. It is difficult to rationalize why binding to and inhibition of cytochrome P-450 would lead to the production of, for examples, liver necrosis.
Animals↗
[Thermal sulfur compounds and esthetic dermatology].
Sulfur compounds are involved in a variety of ways in cosmetics and topical surface treatments. The criterium to be kept in mind is the natural skin-friendliness of sulfur (Comel) and the tangible possibility to influence the morphology and function of the skin by sulfur compounds. Thermal sulfur resources--above all fanghi and baregines--appear to have the appropriate properties for use in aesthetic dermatology. Further basic and clinical studies are needed in order to find scientific support for the indications and uses that are at present contemplated with good reason.
Balneology↗
[Urinary excretion of sulfur compounds following administration of sulfur drugs].
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Dermatologic Agents↗
[Determination of sulfur compounds in fluid catalytic cracking gasoline by gas chromatography with a sulfur chemiluminescence detector].
A method for the separation and determination of sulfur compounds in fluid catalytic cracking gasoline (FCC gasoline) by gas chromatography with a sulfur chemiluminescence detector (GC-SCD) was established. Fifty eight sulfur compounds including mercaptan, sulfide, disulfide, thiophene, alkyl thiophenes, benzothiophene and alkyl benzothiophenes were identified based on their retention indexes and the data obtained from gas chromatography with an atomic emission detector (GC-AED). The effects of flow rate of carrier gas and oven temperature were discussed. Detection reproducibilities of main sulfur compounds (thiophene, n-butyl mercaptan, 2-methylthiophene, 3-methylthiophene, 2,4-dimethylthiophene) in FCC gasoline were satisfactory (RSDs were no more than 5.0%) and detection limit for sulfur was 0.1 mg/L. Using thiophene and benzothiophene as testing samples, it was determined that response factor was independent of the molecular structure of sulfur compounds. The linear range was 0.5-800.0 mg/L sulfur with a correlation coefficient of 0.999.
Catalysis↗
[Analysis of sulfur compounds in residue fluid catalytic cracking gasoline].
Sulfur compounds in residue fluid catalytic cracking (RFCC) gasolines from Refinery of SINOPEC Beijing Yanshan Company and Refinery of Shijiazhuang were analyzed by gas chromatograph connected with flame photometric detector (FPD) and atomic emission detector (AED). Twelve and 26 kinds of sulfur compounds were detected by AED in RFCC gasolines from Yanshan and Shijiazhuang respectively. Only 0 and 19 kinds of sulfur compounds were found by FPD in these two gasolines respectively. The experimental results demonstrated that AED is more sensitive and selective to sulfur compounds than FPD. It also indicated that thiophenes were the major sulfur compounds in the RFCC gasoline. In addition, mercaptan, sulfoether and disulfide species were found.
English Abstract↗
Growth of sulfate-reducing bacteria and methanogenic archaea with methylated sulfur compounds: a commentary on the thermodynamic aspects.
Methylated sulfur compounds such as dimethylsulfoniopropionate, dimethylsulfide, methanethiol, and other methylated sulfur compounds can act as sources of carbon and energy for the growth under anoxic conditions of a number of sulfate-reducing bacteria and methanogenic archaea. We summarise the range of degradative reactions that do or might occur in such organisms, and present thermodynamic data for these processes. These data enable estimates of the feasibility of the reactions as growth-supporting systems, and of the possible maximum growth yields of the bacteria and archaea catalysing them. We compare our new estimates with the few data that are currently available from the literature, and show that some published growth-yield assessments need reevaluation.
3-Mercaptopropionic Acid↗
[Destructive action of copper on various organic sulfur compounds].
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Copper↗
Diversity of sulfur compound production in lactic acid bacteria.
Volatile sulfur compounds such as methanethiol, dimethyl disulfide, dimethyl trisulfide, and hydrogen sulfide constitute an important fraction of Cheddar cheese flavor. These compounds are products of the catabolism of methionine and cysteine by bacteria in the cheese matrix. The objectives of this study were to examine the levels and types of volatile sulfur compounds produced from methionine by lactic acid bacteria frequently used in cheese making and to investigate cystathionine degrading activity, which may be responsible for the liberation of these compounds. Gas chromatography with headspace sampling was used to determine volatile sulfur compounds (VSC) produced by whole cells of 24 strains of lactobacilli and 13 strains of lactococci incubated with methionine. Total VSC production varied widely in the species and subspecies tested. Nearly all strains produced VSC from methionine, but the enzyme responsible for this activity remains unclear. Cystathionine-degrading ability and the effect of methionine concentration on this ability of some of the strains was investigated. Increasing the concentrations of methionine inhibited the cystathionine-degrading ability of lactococci, but not of lactobacilli. Lactococci were found to require methionine for growth, while lactobacilli required both methionine and cysteine. Because of the low level of cystathionine-degrading activity in lactobacilli and the inhibition of this activity by methionine in lactococci, VSC production is likely due to enzymes other than cystathionine beta- and gamma-lyase in whole cells.
Cheese↗
Sensitive quantification of sulfur compounds in wine by headspace solid-phase microextraction technique.
A sensitive solid-phase microextraction and gas chromatography-pulsed flame photometric detection technique was developed to quantify volatile sulfur compounds in wine. Eleven sulfur compounds, including hydrogen sulfide, methanethiol, ethanethiol, dimethyl sulfide, diethyl sulfide, methyl thioacetate, dimethyl disulfide, ethyl thioacetate, diethyl disulfide, dimethyl trisulfide and methionol, can be quantified simultaneously by employing three internal standards. Calibration curves were established in a synthetic wine, and linear correlation coefficients (R2) were greater than 0.99 for all target compounds. The quantification limits for most volatile sulfur compounds were 0.5 ppb or lower, except for methionol which had a detection limit of 60 ppb. The recovery was studied in synthetic wine as well as Pinot noir, Cabernet Sauvignon, Pinot Grigio, and Chardonnay wines. Although the sulfur compounds behaved differently depending on the wine matrix, recoveries of greater than 80% were achieved for all sulfur compounds. This technique was applied to analyze volatile sulfur compounds in several commercial wine samples; methionol concentrations were found at the ppm level, while the concentrations for hydrogen sulfide, methanethiol, and methyl thioacetate were at ppb levels. Only trace amounts of disulfides and trisulfides were detected, and ethanethiol was not detected.
Calibration↗
[Determination of sulfur compounds in catalytic diesel oil by gas chromatography with atomic emission detector and its applications].
The method for separation and determination of sulfur compounds in catalytic diesel oil by gas chromatography with atomic emission detector (GC-AED) was established. More than 130 sulfur compounds (including alkyl thiophenes, benzothiophene, alkyl benzothiophenes, dibenzothiophene, alkyl dibenzothiophenes) in catalytic diesel oil were qualified based on the retention time of some pure sulfur compounds and the retention indexes of sulfur compounds. The effects of oven temperature, heating rate and sample amount on resolution and effective plate number were investigated. Retention indexes of different sulfur compounds under temperature programmed condition were calculated. The relative standard deviations of peak areas of main sulfur compounds in catalytic diesel oil were no more than 5.0%, detection limit for sulfur was 0.1 mg/L under chosen conditions. Because response factor was independent on the molecule structure of the sulfur-containing compound, the content of each sulfur compound was determined quantitatively using thiophene as sulfur standard sample. The linear range was 2 mg/L-1,000 mg/L sulfur, and the correlation coefficient was 0.997. The method is successfully applied for the determination of the contents of sulfur compounds in six different catalytic diesel oils (Fujian catalytic diesel oil, Yanshan catalytic diesel oil, Zhongdong diesel oil, Zhenhai catalytic diesel oil, Zhenhai Changsan oil and Zhenhai Changer oil). Distributions of sulfur compounds in different catalytic diesel oils were obtained by GC-AED.
English Abstract↗
Odorous Sulfur Compounds Emitted during Production of Compost Used as a Substrate in Mushroom Cultivation.
Large-scale composting facilities are known to cause environmental problems, mainly through pungent air emitted by composting material. In air samples taken above stacks set up to prepare compost used as a substrate in mushroom cultivation, several volatile compounds were identified by means of the coupled techniques of gas chromatography and mass spectrography. Among the compounds identified, sulfur-containing compounds [H(2)S, COS, CH(3)SH, CS(2), (CH(3))(2)S, (CH(3))(2)S(2), and (CH(3))(2)S(3)] are the most conspicuous in causing a nuisance. Quantification of these compounds was performed by concentrating a relatively small air sample on Tenax GC. The sampling method appeared to be very useful under field conditions. During the composting process, the concentration of the volatile sulfur compounds in emitted air ranged from 1 to 35 mumol/m. The highest concentrations were obtained at the end of the outdoor process. Total sulfur emission amounted to 8.3 mg of sulfur per kg (fresh weight) of compost. The end product still contained 2.58 g of sulfur per kg (fresh weight) of compost. Suggestions about the origin of the volatile sulfur compounds are made.
Journal Article↗