Isolation and identification of the <Emphasis Type="Italic">thermophilic alkaline desulphuricant</Emphasis> strain

A desulfurization strain that belongs to the thermophilic alkaline desulphuricant is designated as strain GDJ-3 and isolated from Inner Mongolia, China. The colony of the strain shows tiny, yellow, or white-yellow, and it becomes henna with the protracting of cultivated time. The cells are bacilliform (0.3−0.6 × 1.0−1.2 μm), motive, and Gram negative. The strain GDJ-3 is able to utilize respectively the thiosulphate, sulfate, sulfite, or sulfide as sulfur source, utilize the carbon dioxide as the carbon source, and utilize the ammonium or nitrate as the nitrogen source. According to GenBank data, 16s RNA results of GDJ-3 are in good agreement with Alpha proteobacterrium sp. (97%) and Ochrobactrum sp. (98%). For GDJ-3, the optimum growth temperature is at 45°C, the optimum pH is at 8.5–8.8, and the optimum rocking speed of sorting table is at 150 r/min. Under the optimum culture condition, the cells of the strain can live for about 18 h. In the desulfurization solution, which is prepared according to the composition of DDS solution, the objectionable constituents of sodium thiosulphate and sodium sulfide were added factitiously, and the bacterial cell concentration was set at 10⁷/mL. After the regeneration of the above desulfurization solution by the strain cells, the concentration of sodium thiosulphate was decreased by 14.75 g/L (percentage loss of content 13.21%), the concentration of sodium sulfide was decreased by 0.76 g/L (percentage loss of content 87.36%) in the desulfurization solution in 9.5 hours, and sulfur appeared. Maybe, this kind of strain can be used as the regeneration’s bacterial source of DDS solution.     

Deep oxidative desulfurization of benzothiophene and dibenzothiophene with a peroxophosphotungstate–ionic liquid brush assembly

A novel, efficient and reusable heterogeneous catalytic assembly of peroxophosphotungstate held in an ionic liquid brush was synthesized and an extraction and catalytic oxidative desulfurization (ECODS) procedure was developed for a model oil of benzothiophene (BT) and dibenzothiophene (DBT) using 30 wt% hydrogen peroxide as terminal oxidant and methanol as solvent under mild conditions. Several factors that affect sulfur removal were investigated in detail. The highest sulfur removal can reach 100% for BT in 7 h at 70 °C when the molar ratio of H₂O₂, S and catalyst is 10:1:0.025. The sulfur removal for DBT can also reach 100% in 4 h at 50 °C with the same molar ratio of H₂O₂, S and catalyst. The experimental results demonstrate that this ECODS process has no apparent scale‐up effect. The catalyst can be easily recovered (via simple filtration) and recycled five times without a significant decrease in activity. Copyright © 2015 John Wiley & Sons, Ltd.     

Enhancement of Dibenzothiophene Desulfurization by Gordonia alkanivorans Strain 1B Using Sugar Beet Molasses as Alternative Carbon Source

There are several problems limiting an industrial application of fossil fuel biodesulfurization, and one of them is the cost of culture media used to grow the microorganisms involved in the process. In this context, the utilization of alternative carbon sources resulting from agro-industrial by-products could be a strategy to reduce the investment in the operating expenses of a future industrial application. Recently, Gordonia alkanivorans 1B was described as a fructophilic desulfurizing bacterium, and this characteristic opens a new interest in alternative carbon sources rich in fructose. Thus, the goal of this study was to evaluate the utilization of sugar beet molasses (SBM) in the dibenzothiophene (DBT) desulfurization process using strain 1B. SBM firstly treated with 0.25 % BaCl₂ (w/v) was used after sucrose acidic hydrolysis or in a simultaneous saccharification and fermentation process with a Zygosaccharomyces bailii Talf1 invertase (1 %), showing promising results. In optimal conditions, strain 1B presented a μ _max of 0.0795 h^?1, and all DBT was converted to 2-hydroxybiphenyl (250 μM) within 48 h with a maximum production rate of 7.78 μM h^?1. Our results showed the high potential of SBM to be used in a future industrial fossil fuel biodesulfurization process using strain 1B.     

Biodesulfurization of Model Compounds and De-asphalted Bunker Oil by Mixed Culture

In this study, complicated model sulfur compounds in bunker oil and de-asphalted bunker oil were biodesulfurized in a batch process by microbial consortium enriched from oil sludge. Dibenzothiophene (DBT) and benzo[b]naphtho[1,2-d]thiophene (BNT1) were selected as model sulfur compounds. The results show that the mixed culture was able to grow by utilizing DBT and BNT1 as the sole sulfur source, while the cell density was higher using DBT than BNT1 as the sulfur source. GC-MS analysis of their desulfurized metabolites indicates that both DBT and BNT1 could be desulfurized through the sulfur-specific degradation pathway with the selective cleavage of carbon–sulfur bonds. When DBT and BNT1 coexisted, the biodesulfurization efficiency of BNT1 decreased significantly as the DBT concentrations increased (>0.1 mmol/L). BNT1 desulfurization efficiency also decreased along with the increase of 2-hydroxybiphenyl as the end product of DBT desulfurization. For real bunker oil, only 2.8 % of sulfur was removed without de-asphalting after 7 days of biotreatment. After de-asphalting, the biodesulfurization efficiency was significantly improved (26.2–36.5 %), which is mainly attributed to fully mixing of the oil and water due to the decreased viscosity of bunker oil.     

Sulfur-Selective Desulfurization of Dibenzothiophene and Diesel Oil by Newly Isolated Rhodococcus erythropolis NCC-1

A dibenzothiophene （DBT）-desulfurizing bacteria strain was isolated from oil-contaminated soils and identified as Rhodococcus erythropolis NCC-1. Strain NCC-1 was found to convert DBT to hydroxybiphenyl （2-HBP） via the 4S pathway and also be able to use organic sulfur compounds other than DBT as a sole sulfur source. The strain could desulfurize 4,6-dimethyldibenzothiophene （4,6-DMDBT）, which is one of the most recalcitrant dibenzothiophene derivatives to hydrodesulfurization. When two type of oils, a model oil [n-hexadecane （n-C16） containing DBT] and a hydrodesulfurized diesel oil with various organic sulfur compounds, were treated with Rhodococcus erythropolis NCC-1 cells, the total sulfur content significantly decreased, from 150 to 20 mg/L for n-C16 and from 554 to 274 mg/L for diesel oil. The newly isolated strain NCC-1 is considered to have good potential for application in the biodesulfurization of fossil fuels.     

Bio-regeneration of π-complexation desulfurization adsorbents

The coupling of adsorption desulfurization and biodesulfurization is a new approach to produce clean fuels. Sulfur compounds are firstly adsorbed on adsorbents, and then the adsorbents are regenerated by microbial conversion. п-Complexation adsorbent, Cu(l)-Γ, was obtained by ion exchanging Γ-type zeolite with Cu²⁺ and then by auto-reduction in helium at 450°C for 3 h. Dibenzothiophene (DBT) was used as a model compound. The effects of cell concentration, volume of oil phase, the ratio of aqueous phase to adsorbent on DBT desorption by a bacterium were studied. The amounts of DBT desorbed and 2-HBP produced can be apparently increased with addition of n-octane. BDS activity can be improved by increasing cell concentration and the ratio of water-to-adsorbent. 89% of DBT desorbed from the adsorbents can be converted to 2-HBP within 6 h and almost 100% within 24 h, when the volume ratio of oil-to-water was 1/5 mL/mL, the cell concentration was 60 g·L^-1, and the ratio of adsorbent-to-oil was 0.03 g- mL^-1. The amount of 2-HBP produced was strongly dependent on the volume ratio of oil-to-water, cell concentration and amount of adsorbent. Adsorption capacity of the regenerated adsorbent is 95% that of the fresh one after being desorbed with Pseudomonas delafieldii R-8, washed with n-octane, dried at 100°C for 24 h and auto-reduced in He.     

Enhanced Dibenzothiophene Biodesulfurization by Immobilized Cells of Brevibacterium lutescens in n-Octane–Water Biphasic System

In this study, it was the first report that the Brevibacterium lutescens CCZU12-1 was employed as a sulfur removing bacteria. Using dibenzothiophene (DBT) as the sole sulfur source, B. lutescens could selectively degrade DBT into 2-hydroxybiphenyl (2-HBP) via the “4S” pathway. In the basal salt medium (BSM) supplemented with 0.25 mM DBT and 0.5 g/L Tween-80, high desulfurization rate (100 %) was obtained by growth cells after 60 h. Furthermore, the n-octane–water (10:90, v/v) biphasic system was built for the biodesulfurization by resting cells. Moreover, a combination of magnetic nano Fe₃O₄ particles with calcium alginate immobilization was used for enhancing biodesulfurization. In this n-octane–water biphasic system, immobilized B. lutescens cells could be reused for not less than four times. Therefore, B. lutescens CCZU12-1 shows high potential in the biodesulfurization.     

Selection of adsorbents for <Emphasis Type="Italic">in-situ</Emphasis> coupling technology of adsorptive desulfurization and biodesulfurization

In-situ coupling of adsorptive desulfurization and biodesulfurization is a new desulfurization technology for fossil oil. It has the merits of high-selectivity of biodesulfurization and high-rate of adsorptive desulfurization. It is carried out by assembling nano-adsorbents onto surfaces of microbial cells. In this work, In-situ coupling desulfurization technology of widely used desulfurization adsorbents of γ-Al₂O₃, Na-Y molecular sieves, and active carbon with Pseudomonas delafieldii R-8 were studied. Results show that Na-Y molecular sieves restrain the activity of R-8 cells and active carbon cannot desorb the substrate dibenzothiophene (DBT). Thus, they are not applicable to in-situ coupling desulfurization technology. Gamma-Al₂O₃ can adsorb DBT from oil phase quickly, and then desorb it and transfer it to R-8 cells for biodegradation, thus increasing desulfurization rate. It is also found that nano-sized γ-Al₂O₃ increases desulfurization rate more than regular-sized γ-Al₂O₃. Therefore, nano-γ-Al₂O₃ is regarded as the better adsorbent for this in-situ coupling desulfurization technology. Supported by National Basic Research Program of China (Grant No: 2006CB202507) and National High-tech R&D Program (Grant No: 2006AA02Z209)     

MoO3/介孔Al2O3催化氧化脱除模拟油中的硫

以环己烷为溶剂,二苯并噻吩（DBT）、苯并噻吩（BT）、4,6-二甲基二苯并噻吩（4,6-DMDBT）、噻吩（Th）作为模型含硫化合物配制成模拟油,在MoO3/介孔Al2O3-H2O2体系中对模拟油催化氧化脱硫进行了研究. 考察了MoO3负载量、氧化剂用量、催化剂用量、氧化反应温度及反应时间对DBT脱除效果的影响. 实验结果表明：在MoO3负载量为20%,催化剂用量为1.5%,氧化剂H2O2与模拟油中硫的摩尔比为4,反应温度为60℃,反应时间为40分钟时DBT脱除率最高,达99.4%,几乎可以被完全脱除;在此条件下模型化合物的氧化反应活性顺序为：DBT > 4,6-DMDBT >BT>Th.     

Synthesis and non-parametric evaluation studies on high performance of catalytic oxidation-extraction desulfurization of gasoline using the novel TBAPW11Zn@TiO2@PAni nanocomposite

In this work, the new catalyst (assigned as TBAPW₁₁Zn@TiO₂@PAni) was successfully designed and synthesized on the basis of quaternary ammonium salt of zinc monosubstituted phosphotungstate [(n-C₄H₉)₄N][PW₁₁ZnO₃₉] (TBAPW₁₁Zn), titanium dioxide (TiO₂), and polyaniline (PAni). This study reports the catalytic oxidation-extraction desulfurization (ECODS) of sulfur-containing molecules from real and the simulated (Th, BT, and DBT) gasoline using new organic–inorganic hybrid catalyst (TBAPW₁₁Zn@TiO₂@PAni). The ECODS results were shown that the concentration of sulfur compounds (SCs) of real gasoline was lowered from 0.4992 to 0.0122 wt.% with 97% efficiency at 35 °C after 1 h. Furthermore, the synthesized heterogeneous nanocatalyst showed high stability and reusability after five times without significant loss of activity. The high performance of TBAPW₁₁Zn@TiO₂@PAni/H₂O₂/CH₃CO₂H system can be a promising route with a superb potential in the generation of ultra-low-sulfur gasoline. Also the Mann–Whitney U-test results show that there is not a significant difference between the mean of sulfur percentage for DBT & BT, BT & Th and DBT & Th in the presence of the catalyst. Based on the Kruskal–Wallis test results, we can conclude that the temperature, time and amount of catalyst have a significant effect on ECODS efficiency of TBAPW₁₁Zn@TiO₂@PAni nanocomposite.     

Influence of the Carbon Source on Gordonia alkanivorans Strain 1B Resistance to 2-Hydroxybiphenyl Toxicity

The viability of bacteria plays a critical role in the enhancement of fossil fuels biodesulfurization efficiency since cells are exposed to toxic compounds such as 2-hydroxybiphenyl (2-HBP), the end product of dibenzothiophene (DBT) biodesulfurization. The goal of this work was to study the influence of the carbon source on the resistance of Gordonia alkanivorans strain 1B to 2-HBP. The physiological response of this bacterium, pre-grown in glucose or fructose, to 2-HBP was evaluated using two approaches: a growth inhibition toxicity test and flow cytometry. The results obtained from the growth inhibition bioassays showed that the carbon source has an influence on the sensitivity of strain 1B growing cells to 2-HBP. The highest IC₅₀ value was obtained for the assay using fructose as carbon source in both inoculum growth and test medium (IC₅₀-48 h?=?0.464 mM). Relatively to the evaluation of 2-HBP effect on the physiological state of resting cells by flow cytometry, the results showed that concentrations of 2-HBP >1 mM generated significant loss of cell viability. The higher the 2-HBP concentration, the higher the toxicity effect on cells and the faster the loss of cell viability. In overall, the flow cytometry results highlighted that strain 1B resting cells grown in glucose-SO₄ or glucose-DBT are physiologically less resistant to 2-HBP than resting cells grown in fructose-SO₄ or fructose-DBT, respectively.     

Regulating sulfur removal efficiency of fuels by Lewis acidity of ionic liquids

It is urgent to develop a new deep desulfurization process of fuels as the environmental pollution increases seriously. In this work, a series of Lewis acidic ionic liquids (ILs) [C₄³MPy]Cl/nZnCl₂ (n=1, 1.5, 2, 3) were synthesized and used in extraction and catalytic oxidative desulfurization (ECOD) of the fuels. The effects of the Lewis acidity of ILs, the molar ratio of H₂O₂/sulfur, temperatures, and different substrates including dibenzothiophene (DBT), benzothiophene (BT) and thiophene (TS), on sulfur removal were investigated. The results indicated that [C₄³MPy]Cl/₃ZnCl₂ presented near 100% DBT removal of model oil under conditions of 323 K, H₂O₂/DBT molar ratio 6:1. Kinetics for the removal of DBT, BT and TS by the [C₄³MPy]Cl/₃ZnCl₂-H₂O₂ system at 323 K is first-order with the apparent rate constants of 1.1348, 0.2226 and 0.0609 h^-1, and the calculated apparent activation energies for DBT, BT and TS were 61.13, 60.66, and 68.14 kJ/mol from 298 to 308 K, respectively. After six cycles of the regenerated [CC₄³MPy]Cl/₃ZnCl₂, the sulfur removal had a slight decrease. [CC₄³MPy]Cl/₃ZnCl₂ showed a good desulfurization performance under optimal conditions.     

Deep desulfurization of diesel by selective oxidation using amphiphilic paradodecatungstate catalyst

An amphiphilic paradodecatungstate catalyst, [(C₁₈H₃₇)₂N(CH₃)₂]₉[NaH₂W₁₂O₄₂] was prepared and characterized by Fourier transform infrared spectroscopy, UV–visible spectrum, differential thermal analysis, and thermogravimetric analysis. The amphiphilic catalyst exhibits very high catalytic activity that dibenzothiophene (DBT) in model diesel can be oxidized into dibenzothiophene sulfones using hydrogen peroxide as an oxidant. The reactivity of sulfur compounds decreased in the order of DBT > 4,6-DMDBT > BT > 5-MBT. The reaction rates of these sulfur compounds are sensitive to the electron density on sulfur atoms and the steric hindrance of the substituted groups of sulfur compounds. The sulfur level of a commercial diesel after desulfurization can drop from 200 ppm to about 12 ppm.     

利用两种微生物的协同作用进行柴油的深度脱硫

红串红球菌通过4S途径降解二苯并噻吩(DBT)产生 和2-羟基联苯(2-HBP). 和2-HBP的存在对红串红球菌的进一步脱硫有抑制作用, 加入脱 和2-HBP 的菌株可以解除 和2-HBP对红串红球菌脱硫反应的抑制, 使该反应继续向生成产物的方向移动, 从而提高其脱硫率. 在脱硫菌和专一性降解 的水解好氧菌(代号: PYS)的协同作用下可以使高浓度的DBT从1.142 mmol/L降到0.0468 mmol/L, 降解率达到95.9%, 比没有加PYS时提高32%的脱除率. 在油水比为1∶9的条件下, 可以将柴油中的硫从554 mg/mL降到306 mg/mL, 降解率达到44.8%.     

Biodesulfurization of a System Containing Synthetic Fuel Using Rhodococcus erythropolis ATCC 4277

The burning of fossil fuels has released a large quantity of pollutants into the atmosphere. In this context, sulfur dioxide is one of the most noxious gas which, on reacting with moist air, is transformed into sulfuric acid, causing the acid rain. In response, many countries have reformulated their legislation in order to enforce the commercialization of fuels with very low sulfur levels. The existing desulfurization processes cannot remove such low levels of sulfur and thus a biodesulfurization has been developed, where the degradation of sulfur occurs through the action of microorganisms. Rhodococcus erythropolis has been identified as one of the most promising bacteria for use in the biodesulfurization. In this study, the effectiveness of the strain R. erythropolis ATCC 4277 in the desulfurization of dibenzothiophene (DBT) was evaluated in a batch reactor using an organic phase (n-dodecane or diesel) concentrations of 20, 80, and 100 % (v/v). This strain was able to degrade 93.3, 98.0, and 95.5 % of the DBT in the presence of 20, 80, and 100 % (v/v) of dodecane, respectively. The highest value for the specific DBT degradation rate was 44?mmol DBT?·?kg DCW^?1?·?h^?1, attained in the reactor containing 80 % (v/v) of n-dodecane as the organic phase.     

Efficient Extractive Desulfurization of Fuel Oils Using N‐Pyrrolidone/Alkylphosphate‐Based Ionic Liquids

Four BrØsted acid ionic liquids (ILS) [MMP][DMP], [MEP][DEP], [HMP][DMP] and [HEP][DEP] were synthesized and used as extractants for desulfurization of aromatic sulfur compounds in model oil. The mutual solubility of four ILs were investigated. The extraction equilibrium of four ILs could be reached in as soon as 5 min and the extraction capability followed the order [MMP][DMP]>[MEP][DEP]>[HEP][DEP]>[HMP][DMP]. The S extraction showed the highest efficiency under the conditions of 30°C, 30 min and 1:1 (V/V) IL:oil. Under the optimal condition, 70.9% of thiophene (TS), 76.9% of benzothiophene (BT) and 87.5% of dibenzothiophene (DBT) in n‐octane could be efficiently removed by [MMP][DMP]. The multiple extraction and regeneration performance of [MMP][DMP] for TS was also investigated and the results were satisfying. These results suggest that [MMP][DMP] has the best extraction capability and can serve as a promising solvent for extractive desulfurization of fuel oils.     

Deep extractive desulfurization of diesel fuels by FeCl3/ionic liquids

The extractive desulfurization of dibenzothiophene（DBT）,benzothiophene（BT）,and 4,6-dimethyldi-benzothiophene （4,6-DMDBT） in model oil was carried out using anhydrous FeCl₃ and 1-methyl-3-octylimidazolium chloride system（[Omim|Cl·2FeCl₃）.This new system exhibited high extractive efficiency and the sulfur removal of DBT in model oil(V_IL/V_oil=1/20) could reach 99.4%at room temperature for 30 min,which was obviously superior to single[Omim]Cl as extractant（22.9%）.When the[Omim|CI·2FeCl₃ was used,the S-removal of 4,6-DMDBT and BT could also be up to 99.3%and 96.2%, respectively.Moreover,the ionic liquid could be recycled five times without a significant decrease in extractive ability.     

Isolation and characterization of thermophilic benzothiophene-degrading Mycobacterium sp.

A bacterial strain, SWU-4, capable of using benzothiophene (BT) as a sole carbon and energy source was isolated from a petroleum-contaminated site in Thailand and identified by 16S rRNA gene sequence analysis to be in the genus of Mycobacterium. The strain was Gram-positive, nonspore former, and grew at 50° C. Colonies of the strain on nutrient agar were rod-shaped, smooth with a convex surface, slightly mucoid, and yellow pigmented. The thermophilic Mycobacterium sp. strain SWU-4 rapidly degraded 2% (w/v) BT at 50°C. Interestingly, this strain was able to degrade a wide variety of organosulfur compounds including thiophene, bromo(α)thiophene, and 3-methylthiophene in liquid minimum medium at 50°C, which will be beneficial for industrial applications.     

Inactivation of Botrytis cinerea during thermophilic composting of greenhouse tomato plant residues

The effectiveness of in-vessel thermophilic composting on the inactivation of Botrytis cinerea was evaluated. The bioreactor operated on an infected mixture of tomato plant residues, wood shavings, and municipal solid compost (1∶1.5∶0.28). Tap water and urea were added to adjust the moisture content and C∶N ratio to 60% and 30∶1, respectively. Used cooking oil was added as a bioavailable carbon source to compensate for heat losses from the system and extend the thermophilic compositing stage. The controlled thermophilic composting process was successful in inactivating B. cinerea. During all experiments, the average reactor temperature increased gradually, reaching its peak after 31 h of operation. Temperatures in the range of 62.6–63.9°C were maintained during the thermophilic stage by the intermittent addition of used cooking oil. The results of the enzyme-linked immunosorbent assay test indicated that the initial concentration of B. cinerea in the compost samples (14.6 μg of dried mycelium/g of compost) was reduced to 12.9, 8.8, and 2.4 μg/g after 24, 48, and 72 h of thermophilic composting, respectively. Plating assay indicated that the mold was completely inactivated in samples after 48 h of thermophilic composting. No significant reduction in B. cinerea was observed during the transient phase (first 30 h of rising temperature) because the temperature reached the lethal level of 55°C after 23 h, thus allowing only 7 h of exposure to temperatures higher than 55°C during this phase. The relatively short time required for complete inactivation of B. cinerea was achieved by maintaining a constant high temperature and a uniform distribution of temperature and extending the duration of the thermophilic stage by the addition of the proper amount of bioavailable carbon (used cooking oil).     

Interactions of thiophenes with C300 Basolite MOF in solution by the temperature-programmed adsorption and desorption,spectroscopy and simulations

Aromatic sulfur compounds, e.g. thiophene (T), benzothiophene (BT), dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT) are present in petroleum and fossil fuels, and cause air pollution, degradation of catalytic converters, deactivation of fuel-reforming catalysts. In this paper, we report kinetic, thermodynamic, spectroscopic and computational studies of adsorption of T, BT, DBT, and 4,6-DMDBT from solution in n-alkane on metal–organic framework (MOF) Basolite C300 at 25–115 °C. The novel temperature-programmed adsorption/desorption method allows the in situ measurement of an adsorption capacity at the variable temperature, and after the cycle “adsorption/desorption”. Adsorption of BT, DBT and 4,6-DMDBT at 25 °C occurs via the formation of the stoichiometric 1:1 adsorption complexes. BT adsorbs reversibly, while 4,6-DMDBT adsorbs irreversibly. The formation of the adsorption complex of the aromatic sulfur compound with MOF is confirmed by the fluorescence spectroscopy for the first time. The DFT computations of the geometry and energy of dispersive versus electronic interactions of T and DBT with the structural units of the C300 MOF are reported for the first time. The mechanism of adsorption is proposed as a combination of dispersive and electronic interactions of the aromatic sulfur compounds with BTC linker and Cu(II) CUS of C300 MOF.