Organic Sulfur Compounds Research Articles

Sulfide mineral dissolution microbes: Community structure and function in industrial bioleaching heaps

Heap bioleaching is one of the most clean and economical processes for recovery of low-grade and complex ores, because the sulfide minerals are natural habitats for acidophiles capable of iron- and sulfur-oxidation. The most exciting advances in heap bioleaching are occurring in the field of microbiology, especially with the development of advanced molecular biology approaches. These chemolithotrophic microorganisms living in the acid mine environment fix N2 and CO2 and obtain energy for growth from soluble ferrous iron and reduced inorganic sulfur compounds during oxidation of sulfide minerals. The ferric iron as oxidant and sulfuric acid are a result of microbial activity and provide favorable conditions for the dissolution of sulfide minerals. Various microbial consortia were applied successfully in commercial bioleaching heaps around the world, and microbial community and activity were adapted related to the local climatic conditions, ore characteristics and engineering configuration. This review focuses on diversity of bioleaching microbes, their role in heap bioleaching processes, their community structure and function in industrial heaps and the relation to the ore characteristics and the engineering configuration, to give implications for optimizing leaching efficiency of heap bioleaching.

A comparative study of the emission of volatile organic compounds (VOCs) from different sulfur content crude oils

ABSTRACTA new lab-made passive sampler method was employed to collect volatile organic compounds (VOCs) and volatile sulfur compounds (VSCs) which they were emitted from the spill of two different sulfur content crude oils. In this study, two different models have been used to represent of spill crude oil in two different areas, a laboratory and field model for spill crude oil on the surface area and pipeline leak respectively. The effective meteorological parameters such as rain, wind speed, and air temperature were controlled. The results show that the emitted VOCs were inversely proportional to the sulfur content crude oils.

Origin of polar organic sulfur compounds in immature crude oils revealed by ESI FT-ICR MS

Organic sulfur compounds (OSCs) are abundant in immature crude oils, including “polar” OSCs that are defined here as compounds containing one or more heteroatom(s) in addition to sulfur atoms having sufficient polarity to be analyzable by electrospray ionization (ESI) without derivatization. An understanding of the origins of polar OSCs in crude oils has been hampered by limitations in their analytical characterization. In this paper, we employed a high field (9.4 T) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) coupled with ESI to study the sulfur-rich immature crude oils from the Jianghan Basin in China. The results show that the polar OSCs usually have non-sulfur counterparts, i.e., heteroatom-containing compounds without sulfur, with similar carbon number ranges, but slightly lower DBE (double bond equivalence) distributions. The similar or even identical carbon number distributions of the polar OSCs and their non-sulfur counterparts indicate their inheritance from the same precursors. The sulfur rings in polar OSCs are formed by intramolecular sulfurization that leads to the increases in DBEs compared to their non-sulfur counterparts. The results also indicate that the number of sulfur rings that can be formed in polar OSCs is largely controlled by the number of available reactive functional groups in their precursors. This paper extends our knowledge of intramolecular sulfurization during early diagenesis, especially for polar heteroatom-containing compounds.

Treatment of Saos-2 osteosarcoma cells with diallyl trisulfide is associated with an increase in calreticulin expression.

Diallyl trisulfide (DATS) is a natural organic sulfur compound that may be isolated from garlic and has strong anticancer activity. DATS has been demonstrated to upregulate the expression of calreticulin (CRT) in various types of human cancers, which is associated with the prognosis of cancer and its response to therapy. However, whether DATS has the same effect on human osteosarcoma cells is not known. Therefore, in the present study, Saos-2 human osteosarcoma cells were cultured with different concentrations of DATS (0, 25, 50 and 100 µmol/l) for 24 h, or with 50 µmol/l DATS for different time periods (0, 12, 24 and 36 h). Reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blotting and immunofluorescent staining were used to detect CRT mRNA and protein in the Saos-2 cells. Exposure to DATS changed the morphology and inhibited the growth of the Saos-2 cells, and its effects appeared to be concentration- and exposure time-dependent. The optimum concentration and exposure time of DATS were 50 µmol/l and 24 h, respectively. The levels of CRT mRNA and protein in the Saos-2 cells were significantly upregulated following exposure to DATS. The upregulation of CRT expression by DATS may be a mechanism underlying the ability of DATS to inhibit the growth of human osteosarcoma Saos-2 cells.

A XANES Study of Sulfur Speciation and Reactivity in Cokes for Anodes Used in Aluminum Production

Availability of anode raw materials in the growing aluminum industry results in a wider range of petroleum cokes being used to produce carbon anodes. The boundary between anode grade cokes and what previously was considered non-anode grades are no longer as distinct as before, leading to introduction of cokes with higher sulfur and higher trace metal impurity content in anode manufacturing. In this work, the chemical nature of sulfur in five industrial cokes, ranging from 1.42 to 5.54 wt pct S, was investigated with K-edge XANES, while the reactivity of the cokes towards CO2 was measured by a standard mass loss test. XANES identified most of the sulfur as organic sulfur compounds. In addition, a significant amount is identified (16 to 53 pct) as S-S bound sulfur. A strong inverse correlation is observed between CO2-reactivity and S-S bound sulfur in the cokes, indicating that the reduction in reactivity is more dependent on the amount of this type of sulfur compound rather than the total amount of sulfur or the amount of organic sulfur.

Optimization of Substrate and Starter Cell Concentrations for Dibenzothiopene Biodegradation by Indigeneous Marine Bacteria <i>Mauricauda olearia</i> LBF-1-0009, <i>Alcanivorax xenomutants</i> LBF-1-0018, and <i>Stakelama pacifica</i> LBF-1-0031

Dibenzothiophene (DBT) and its derivatives have been widely used as model organic sulfur compounds in petroleum, included their biodegradation process. The abilities of microorganisms to degrade pollutants are significantly influenced by various factors such as microbial species, nutrients and environmental parameters. In this research, we carried out further study to determine optimal condition for DBT biodegradation regarding with substrate and strains cell concentration by several indigenous marine bacteria from Indonesia. These three isolates were belong to Mauricauda olearia, Alcanivorax xenomutants, and Stakelama pacifica, with homology result 99% each. Optimal dibenzothiophene as substrate reached by all isolates is 100 ppm, while cell concentration or microbial numbers that gave highest growth for all isolates is 20 based on conversion of OD600 nm measurement.

Peatland Acidobacteria with a dissimilatory sulfur metabolism

Sulfur-cycling microorganisms impact organic matter decomposition in wetlands and consequently greenhouse gas emissions from these globally relevant environments. However, their identities and physiological properties are largely unknown. By applying a functional metagenomics approach to an acidic peatland, we recovered draft genomes of seven novel Acidobacteria species with the potential for dissimilatory sulfite (dsrAB, dsrC, dsrD, dsrN, dsrT, dsrMKJOP) or sulfate respiration (sat, aprBA, qmoABC plus dsr genes). Surprisingly, the genomes also encoded DsrL, which so far was only found in sulfur-oxidizing microorganisms. Metatranscriptome analysis demonstrated expression of acidobacterial sulfur-metabolism genes in native peat soil and their upregulation in diverse anoxic microcosms. This indicated an active sulfate respiration pathway, which, however, might also operate in reverse for dissimilatory sulfur oxidation or disproportionation as proposed for the sulfur-oxidizing Desulfurivibrio alkaliphilus. Acidobacteria that only harbored genes for sulfite reduction additionally encoded enzymes that liberate sulfite from organosulfonates, which suggested organic sulfur compounds as complementary energy sources. Further metabolic potentials included polysaccharide hydrolysis and sugar utilization, aerobic respiration, several fermentative capabilities, and hydrogen oxidation. Our findings extend both, the known physiological and genetic properties of Acidobacteria and the known taxonomic diversity of microorganisms with a DsrAB-based sulfur metabolism, and highlight new fundamental niches for facultative anaerobic Acidobacteria in wetlands based on exploitation of inorganic and organic sulfur molecules for energy conservation.

Draft Genome Sequence of Acidithiobacillus sp. Strain SH, a Marine Acidophilic Sulfur-Oxidizing Bacterium.

ABSTRACTWe announce here the genome sequence of a marine acidophilic sulfur-oxidizing bacterium, Acidithiobacillus sp. strain SH. The bacterium has potential for use in bioleaching of sulfide ores from seawater and contains a noble gene for thiosulfate quinone oxidoreductase in addition to specific genes for the oxidation of reduced inorganic sulfur compounds.

Resuspendable Powders of Lyophilized Chalcogen Particles with Activity against Microorganisms.

Many organic sulfur, selenium and tellurium compounds show considerable activity against microorganisms, including bacteria and fungi. This pronounced activity is often due to the specific, oxidizing redox behavior of the chalcogen-chalcogen bond present in such molecules. Interestingly, similar chalcogen-chalcogen motifs are also found in the elemental forms of these elements, and while those materials are insoluble in aqueous media, it has recently been possible to unlock their biological activities using naturally produced or homogenized suspensions of respective chalcogen nanoparticles. Those suspensions can be employed readily and often effectively against common pathogenic microorganisms, still their practical uses are limited as such suspensions are difficult to transport, store and apply. Using mannitol as stabilizer, it is now possible to lyophilize such suspensions to produce solid forms of the nanoparticles, which upon resuspension in water essentially retain their initial size and exhibit considerable biological activity. The sequence of Nanosizing, Lyophilization and Resuspension (NaLyRe) eventually provides access to a range of lyophilized materials which may be considered as easy-to-handle, ready-to-use and at the same time as bioavailable, active forms of otherwise insoluble or sparingly substances. In the case of elemental sulfur, selenium and tellurium, this approach promises wider practical applications, for instance in the medical or agricultural arena.

The investigation on the removal mechanism of organic sulphur in coal under the external energy

In order to explore the removal mechanism of organic sulphur in coal with microwave. The desulfurisation experiment of high sulphur coal with microwave and the response experiments of organic sulphur compounds to microwave are carried out respectively. The change regularity of the organic sulphur compounds in coal under the different external energy are studied with the density functional theory. The results show that the chemical activity of the organic sulphur change with the electric field close to the microwave energy, and the external energy can impact on the molecular internal energy. Comparing molecular transformation of the different organic sulphur compounds under the external energy, the test results of microwave desulfurisation and the theoretical calculation of electric dipole moment change under the external energy, it can get that the difficulty of the microwave desulfurisation corresponds to the molecular polarity. It illustrates why the thiophenic sulphur in coal is difficult to remove. [Received: February 9, 2017; Accepted: September 1, 2017]

Chemical compositional analysis of the Tamarix hispida aerial part extract obtained in ethanol solutions of different concentration

In this article, extracts from aerial part of Tamarix hispida Wild harvested in 2016 in the Ile District of the Almaty Region during the flowering period are considered. A comparative analysis of chemical composition of extracts obtained with three extracting agents constituting ethyl alcohol solutions concentrated differently (96%, 70%, 50%) has been made; the extracts were studied by high-performance liquid chromatography with a mass-selective detector Aligent Technologies 6400 Series Triple Quadrupole LC/MS, and were identified by mass spectra and retention times using the NIST library and Wiley LC/MS. In all the three extracts, various phthalic esters are dominant compounds, those are: Phthalicacid, octyl 2-pentylester in 96% extract, 1,2-Benzenedicarboxylicacid, decyloctylester in 70% extract, and Phthalicacid, hexadecyl 2-methylbutylester in 50% extract; also, a high content of alkaloids of various groups was identified in all the extracts, for example, 4-t-Butyl-2-(4-methoxy-phenyl)-6-p-tolyl-pyridine in 96% extract, Morphinan- 4,6-diol, N-formyl-6-acetate (ester) in 70% extract, and 7-Methylthieno [3,2-b] pyridine in 50% extract. All of the above parameters are quite high for alkaloids in wild plants growing in Central Asia, while it should be noted that the highest alkaloid content is found in 70% alcohol extracts from aerial part of Tamarix hispida. Nitrogen-containing compounds are present in all the three extracts with the largest variety of compounds, with both nitrogen-containing dyes and alkaloids present therein. Apart from the above, a number of noteworthy metabolites containing halogens, such as Methyl (((1E)-2-(4-chlorophenyl)-3-[4-(2-furoyl)-1-piperazinyl]-3-thioxo-1-propenyl) amino) acetate (4,4%), Alclometasone Dipropionate have been identified in the 50% Tamarix hispida aerial part extract. Analysis of the literature data allows for a conclusion that a high content of nitrogen-containing compounds is characteristic of the Chenopodioídeae; thus, for example, plants of the Sueda genus, Halostachys and Ephedra are sources of alkaloids of the piperidine and pyrrole, pyrolidinium and morphine groups; however, the content of organic sulfur and organochlorine compounds in the Tamarix genus was not previously reported, although these classes are quite common in the Embryophytes.

Experimental study of inhibitory effects of diallyl trisulfide on the growth of human osteosarcoma Saos-2 cells by downregulating expression of glucose-regulated protein 78.

BackgroundDiallyl trisulfide (DATS) is a natural organic sulfur compound isolated from garlic that has good anticancer activity according to many previous reports. There are many studies pointing out that DATS can downregulate expression of the glucose-regulated protein 78 (GRP78), which is associated with poor prognosis and drug resistance in various types of human cancers. However, it remains unknown whether DATS has the same effect on human osteosarcoma cells. This study attempted to clarify the potential molecular mechanisms of the action of DATS in human osteosarcoma Saos-2 cells.MethodsWe used an inverted phase microscope and immunofluorescent staining to observe the morphological changes of Saos-2 cells after being cultured in different concentrations of DATS (0, 25, 50, and 100 μM) for 24 h, or for four time periods (24, 48, 72, and 96 h) in the same DATS concentration (50 μM). Quantitative real-time polymerase chain reaction and Western blot were used to detect the expression level of GRP78 mRNA and proteins in Saos-2 cells. GRP78 expression was suppressed in Saos-2 cells by utilizing small-interfering RNA, and the cells were subsequently used to study the anti-proliferative effects of DATS treatment.ResultsThe expression level of GRP78 mRNA and proteins was significantly downregulated due to the increased concentration and effective times of DATS (P<0.05). In addition, there were significant associations between GRP78 silencing and cell proliferation (P<0.05) of DATS treatment.ConclusionThese results indicate that DATS inhibits the growth of human osteosarcoma Saos-2 cells by downregulating the expression of GRP78.

UJI AKTIVITAS EKSTRAK ETANOL BAWANG PUTIH (Alliumsativum L.)YANG DIHITAMKAN SEBAGAI ANTI INFLAMASI YANG DIINDUKSI OLEH KARAGENAN TERHADAP Mus musculus

One of the plants used as an alternative to traditional medicine is Garlic (Allium sativum L.). Garlic which is rich in organic organo sulfur compounds (amino acids and essential oils) in the form of allin has many benefits in treating various types of diseases. One of the processed forms of garlic is black garlic. Black garlic is a heating product from garlic that is heated at a temperature of 70oC with a relative humidity of 70-80%. This study aims to determine the use of black garlic as an anti-inflammatory, how to make black garlic and at what concentration black garlic has an anti-inflammatory effect. The method used in this research is a pure experimental method. The results of the %R measurement, the negative control group had the highest level of inflammation and the lowest was the black garlic extract group with a concentration of 60%. Meanwhile, in the %IR measurement, the black garlic extract group with a concentration of 60% had the greatest ability to block inflammation. From the tests that have been carried out, black garlic is obtained from heating results and the results of measuring the effectiveness of its anti-inflammatory activity, namely black garlic extract with a concentration of 60% have a better anti-inflammatory effect compared to other concentrations and diclofenac sodium.

Optimization of Substrate and Starter Cell Concentrations for Dibenzothiopene Biodegradation by Indigeneous Marine Bacteria Mauricauda olearia LBF-1-0009, Alcanivorax xenomutants LBF-1-0018, and Stakelama pacifica LBF-1-0031

Dibenzothiophene (DBT) and its derivatives have been widely used as model organic sulfur compounds in petroleum, included their biodegradation process. The abilities of microorganisms to degrade pollutants are significantly influenced by various factors such as microbial species, nutrients and environmental parameters. In this research, we carried out further study to determine optimal condition for DBT biodegradation regarding with substrate and strains cell concentration by several indigenous marine bacteria from Indonesia. These three isolates were belong to Mauricauda olearia, Alcanivorax xenomutants, and Stakelama pacifica, with homology result 99% each. Optimal dibenzothiophene as substrate reached by all isolates is 100 ppm, while cell concentration or microbial numbers that gave highest growth for all isolates is 20 based on conversion of OD600 nm measurement.

Genome-wide identification and cadmium induced expression profiling of sulfate transporter (SULTR) genes in sorghum (Sorghum bicolor L.).

Sulfur is an essential element for all living organisms. Plants can convert inorganic sulfur into organic sulfur compounds by complex enzymatic steps. In this study, we conducted agenome-wide analysis of sulfate transporter genes (SULTRs) in the sorghum (Sorghum bicolor) genome and examined expression profiles of SbSULTR genes under 200µM cadmium (Cd) exposure. As a result of sorghum genome analysis, 11 SULTR genes were identified, including SbSULTR1;1, SbSULTR1;2, SbSULTR1;3, SbSULTR2;1, SbSULTR2;2, SbSULTR3;1, SbSULTR3;2, SbSULTR3;3, SbSULTR3;4, SbSULTR3;5, and SbSULTR4. Given names are based on phylogeny and chromosomal locations. Except SbSULTR4, all SbSULTR proteins contained Sulfate_transp (PF00916), STAS (PF01740) domains and 12 trans-membrane domains. Phylogenetic analysis revealed that four major groups were identified such as SULTR1, 2, 3, and 4 groups and SULTR4 group was separated to other SULTR groups. In promotor sequences of SbSULTR genes, many diverse cis-acting elements were found mainly related with physiological processes such as light, stress and hormone responsiveness. The expression profiles of SbSULTR genes showed that SULTR1;2, 1;3, 3;3, and 3;5 genes up-regulated in root, while expression level of SULTR4 decreased under 200µM Cd exposure. The predicted 3D structures of SULTR proteins showed some conformational changes, suggesting functional diversities of SbSULTRs. Finally, results of this study may contribute towards understanding SbSULTR genes and their regulations and roles in Cd stress in sorghum.

Oxygenation of Hypoxic Coastal Baltic Sea Sediments Impacts on Chemistry, Microbial Community Composition, and Metabolism.

The Baltic Sea has undergone severe eutrophication during the last century, resulting in increased algal blooms and the development of hypoxic bottom waters. In this study, we sampled oxygen deficient sediment cores from a Baltic Sea coastal bay and exposed the bottom water including the sediment surface to oxygen shifts via artificial addition of air during laboratory incubation. Surface sediment (top 1 cm) from the replicate cores were sliced in the field as well as throughout the laboratory incubations and chemical parameters were analyzed along with high throughput sequencing of community DNA and RNA. After oxygenation, dissolved iron decreased in the water overlying the sediment while inorganic sulfur compounds (thiosulfate and tetrathionate) increased when the water was kept anoxic. Oxygenation of the sediment also maintained RNA transcripts attributed to sulfide and sulfur oxidation as well as nitrogen fixation in the sediment surface. Based on 16S rRNA gene and metatranscriptomic analyses it was found that oxygenation of the sediment surface caused a bloom of the Epsilonproteobacteria genus Arcobacter. In addition, the formation of a thick white film was observed that was likely filamentous zero-valent sulfur produced by the Arcobacter spp. Based on these results, sulfur cycling and nitrogen fixation that were evident in the field samples were ongoing during re-oxygenation of the sediment. These processes potentially added organic nitrogen to the system and facilitated the re-establishment of micro- and macroorganism communities in the benthic zone.

Development of PCR primer systems for amplification of 16S-rDNA to detect of Thiobacillus spp.

Thiobacillus is a genus of Gram-negative, rod-shaped and autotrophic Betaproteobacteria. They catalyze the dissimilatory oxidation of elemental sulfur and reduced inorganic sulfur compounds. Whereas more than 30 species have been known in this genus, most were never reliably or effectively published. The rest were either reclassified into Thiomonas, Paracoccus, Starkeya, Sulfuriferula, Halothiobacillus, Thermithiobacillus or Acidithiobacillus, were lost from culture. Most of Thiobacillus species are obligate autotrophs via elementary sulfur, thiosulfate or polythionates as energy sources. Based on 16S ribosomal RNA sequence analysis, many members of Thiobacillus have been reclassified. A system was developed for the detection of Thiobacillus bacteria by the amplification of specific 16S ribosomal RNA sequence gene (16S rDNA) fragments with PCR. Primer sequences were designed for the amplification of fragments of 16S rDNA.

Experimental investigation on thermochemical sulfate reduction in the presence of 1-pentanethiol at 200 and 250 °C: Implications for in situ TSR processes occurring in some MVT deposits

Organic sulfur compounds are ubiquitous in natural oil and gas fields and moderate-low temperature sulfide ore deposits. Previous studies have shown that organic sulfur compounds are important in enhancing the rates of thermochemical sulfate reduction (TSR) reactions, but the details of these reaction mechanisms remain unclear. In order to assess the extent of sulfate reduction in the presence of labile sulfur species at temperature conditions near to those where TSR occurs in nature, we conducted a series of experiments using the fused silica capillary capsule (FCSS) method. The tested systems containing labile sulfur species are MgSO4 + 1-pentanethiol (C5H11SH) + 1-octene (C8H16), MgSO4+1-octene (C8H16), MgSO4+1-pentanethiol (C5H11SH), 1-pentanethiol (C5H11SH)+H2O, and MgSO4 + 1-pentanethiol (C5H11SH) + ZnBr2 systems. Our results show that: (1) intermediate oxidized carbon species (ethanol and acetic acid) are formed during TSR simulation experiments when 1-pentanethiol is present; (2) in the presence of ZnBr2, 1-pentanethiol can be oxidized by sulfate to CO2 at 200 °C, which is within the temperature range observed in natural TSR; and (3) the precipitation of sulfide minerals may significantly promote the rate of TSR, indicating that the rates of in situ TSR reactions in ore deposits could be much faster than previously thought. This may be important for understanding the possibility of in situ TSR as a mechanism for the precipitation of metal sulfides in some ore deposits. These findings provide important experimental evidence for understanding the role of organic sulfur compounds in TSR reactions and the pathway of TSR reactions initiated by organic sulfur compounds under natural conditions.

Emissions of volatile sulfur compounds (VSCs) throughout wastewater biosolids processing

Volatile sulfur compounds (VSCs) are important contributors to nuisance odours from the processing of wastewater sludge and biosolids. However, emission characteristics are difficult to predict as they vary between sites and are likely to be affected by biosolids processing configuration and operation. VSC emissions from biosolids throughout 6 wastewater treatment plants (WWTPs) in Sydney, Australia were examined in this study. H2S was the VSC found at the highest concentrations throughout the WWTPs, with concentrations ranging from 7 to 39,000μg/m3. Based on odour activity values (OAVs), H2S was typically also the most dominant odorant. However, methyl mercaptan (MeSH) was also found to be sensorially important in the biosolids storage areas given its low odour detection threshold (ODT). High concentrations of VOSCs such as MeSH in the storage areas were shown to potentially interfere with H2S measurements using the Jerome 631-X H2S sensor and these interferences should be investigated in more detail. The VSC composition of emissions varied throughout biosolids processing as well as between the different WWTPs. The primary sludge and biosolids after dewatering and during storage, were key stages producing nuisance odours as judged by the determination of OAVs. Cluster analysis was used to group sampling locations according to VSC emissions. These groups were typically the dewatered and stored biosolids, primary and thickened primary sludge, and waste activated sludge (WAS), thickened WAS, digested sludge and centrate. Effects of biosolids composition and process operation on VSC emissions were evaluated using best subset regression. Emissions from the primary sludge were dominated by H2S and appeared to be affected by the presence of organic matter, pH and Fe content. While volatile organic sulfur compounds (VOSCs) emitted from the produced biosolids were shown to be correlated with upstream factors such as Fe and Al salt dosing, anaerobic digestion and dewatering parameters.

Sulfur Transformation Characteristics and Mechanisms during Hydrogen Production by Coal Gasification in Supercritical Water

Coal supercritical water gasification (SCWG) is famous for generating clean gas without SOx pollutant. Study of sulfur transformation characteristics can provide the basis of sulfur removal during hydrogen production by coal gasification in supercritical water (SCW) at the source. In this work, two coals produced from Linfen and Zhangjiamao in China (hereinafter to be referred as L-coal and Z-coal), were chosen as experimental feedstocks to investigate sulfur transformation characteristics during hydrogen production by coal gasification in SCW (550–750 °C, 20 min, 25 MPa). Sulfur transformation pathway and sulfur forms in the products were complex but detected comprehensively. H2S was the only gaseous product instead of SOx, whereas SO42– was the main liquid–sulfur product. Inorganic and organic sulfur compounds were used to investigate sulfur transformation mechanisms. H2S had three sources as follows. First, among inorganic sulfur of raw coal, FeS2 (Pyrite) was chemically stable in SCW lacking of hydrog...