Long-term repeated biodesulfurization by immobilized Rhodococcus erythropolis KA2-5-1 cells

Naito, M.; Kawamoto, Takuo; Fujino, Kazuhito; Kobayashi, Morio; Maruhashi, Kenji; Tanaka, Atsuo

doi:10.1007/s002530000527

Cited by 62 publications

(37 citation statements)

References 13 publications

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“…So far, only a few reports on the use of biocatalyst immobilization, such as entrapment or adsorption on Celite in biodesulfurization, have been published (4,10,15). However, the methods have some limitations, such as a mass transfer problem, loss of cells, and separation of biocatalysts from the treated oils.…”

Section: Discussionmentioning

confidence: 99%

Biodesulfurization of Dibenzothiophene by Microbial Cells Coated with Magnetite Nanoparticles

Shan

Xing

Zhang

et al. 2005

Appl Environ Microbiol

179

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Section: Discussionmentioning

confidence: 99%

Biodesulfurization of Dibenzothiophene by Microbial Cells Coated with Magnetite Nanoparticles

Shan

Xing

Zhang

et al. 2005

Appl Environ Microbiol

179

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“…It has been suggested that the formation of a stable water/oil emulsion should be avoided in order to facilitate oil recovery (Ayala & Vazquez-Duhalt, 2004). A BDS process using immobilized cells has been also described (Naito et al, 2001;Lee et al, 2005); by this method it is possible to devise a two-phase system (immobilized cells and oil) to desulfurize oil without any particle-stabilized emulsion formation. It has been reported that the desulfurizing activity in the two-phase system is lower than that of the three-phase system, probably due to the interference of the support with the diffusion of substrates and products (Alaya & Vazquez-Duhalt, 2004).…”

Section: Discussionmentioning

confidence: 99%

Stabilization of water/gas oil emulsions by desulfurizing cells of Gordonia alkanivorans RIPI90A

et al. 2007

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It has been previously reported that resting-cells, non-proliferating cells, of Gordonia alkanivorans RIPI90A can convert dibenzothiophene (DBT) to 2-hydroxybiphenyl (2-HBP) via the 4S pathway in a biphasic system. The main goal of the current work was to study the behaviour of resting-cells of this strain in biphasic organic media. Resting-cells showed strong affinity for sulfurous organic substrates and were able to stabilize water/gas oil emulsions by attaching to the interface without decreasing the surface tension of their environment. This was consistent with the behaviour of the whole cells but not the surfactants, suggesting that microbial cell-mediated emulsification occurs. It was found that the emulsion-stabilizing activity of the resting-cells was influenced by the growth stage, but was not directly influenced by the metabolic activity of the resting-cells. This activity may be related to cell-surface hydrophobicity, which results from the unique chemical structure of the cell surface. In some biphasic biodesulfurization (BDS) bioreactors, emulsions are created without addition of any surfactant. Cell surface-mediated stabilization helps prolong the emulsions and therefore overcomes mass-transfer limitations in bioreactors. The simultaneous occurrence of emulsion-stabilizing and desulfurization activities of resting-cells was observed for what is believed to be the first time. The results suggest that this strain may have potential for the BDS of diesel oils.

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“…Cells were immobilized by entrapment with calcium alginate, carrageenan, agar, polyvinyl alcohol, polyacrylamide, and gelatin-glutaraldehyde. We found that calcium alginate-immobilized cells had the highest DBT desulfurization activity, and therefore calcium alginate was selected as the biosupport material for this study (3,26). Bacteria were cultured in MAM containing 0.5 mM DBT or 1 mM dimethyl sulfoxide as the sole sulfur source at 45°C.…”

Section: Methodsmentioning

confidence: 99%

Microbial Desulfurization of Gasoline in a Mycobacterium goodii X7B Immobilized-Cell System

Feng

et al. 2005

Appl Environ Microbiol

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Mycobacterium goodii X7B, which had been primarily isolated as a bacterial strain capable of desulfurizing dibenzothiophene to produce 2-hydroxybiphenyl via the 4S pathway, was also found to desulfurize benzothiophene. The desulfurization product was identified as o-hydroxystyrene by gas chromatography (GC)-mass spectrometry analysis. This strain appeared to have the ability to remove organic sulfur from a broad range of sulfur species in gasoline. When Dushanzi straight-run gasoline (DSRG227) containing various organic sulfur compounds was treated with immobilized cells of strain X7B for 24 h, the total sulfur content significantly decreased, from 227 to 71 ppm at 40°C. GC flame ionization detection and GC atomic emission detection analysis were used to qualitatively evaluate the effects of M. goodii X7B treatment on the contents of gasoline. In addition, when immobilized cells were incubated at 40°C with DSRG275, the sulfur content decreased from 275 to 54 ppm in two consecutive reactions. With this excellent efficiency, strain X7B is considered a good potential candidate for industrial applications for the biodesulfurization of gasoline.Sulfur oxides released from fossil fuel combustion contribute to acid rain and air pollution (11,24). With the increasing demands for energy and more stringent environmental policies, deep desulfurization of petroleum is becoming more and more desired. In terms of available technologies, the sulfur content in gasoline can be reduced to Ͻ30 ppm by current hydrotreatment processes. The major problem with deep desulfurization of gasoline is that conventional hydrodesulfurization (HDS) technology results in a significant reduction in the octane number due to the saturation of olefins in naphtha from fluid catalytic cracking, which also causes more hydrogen consumption (21). However, thiophenic compounds such as benzothiophene (BTH) and thiophene (T) and their derivates, as well as thiol, are major sulfur compounds in gasoline (23). If biodesulfurization (BDS) can be applied effectively to gasoline, the refiner will be offered a less expensive alternative to HDS that also avoids the drawback of octane degradation (20). Several studies on BTH-and dibenzothiophene (DBT)-desulfurizing bacteria have been reported (8,13,14,22,30,31).The desulfurization pathway of Rhodococcus erythropolis IGTS8 (9) has been characterized. The dszA, -B, and -C genes, which are responsible for DBT desulfurization, have been cloned and sequenced, and their products have been characterized (5,6,16,17,19,27). In addition, the BTH desulfurization pathway has been demonstrated for six bacteria: Gordonia sp. strain 213E (8), Rhodococcus sp. strain T09 (22), Paenibacillus sp. strain A11-2 (14), Sinorhizobium sp. strain KT55 (31), Rhodococcus sp. strain KT 462 (30), and Rhodococcus sp. strain WU-K2R (13). Furthermore, the desulfurization of both DBT and BTH by a single bacterium has only been reported for Paenibacillus sp. strain A11-2 (14) and Rhodococcus sp. strain KT462 (30). On the other hand, since distillate...

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Long-term repeated biodesulfurization by immobilized Rhodococcus erythropolis KA2-5-1 cells

Cited by 62 publications

References 13 publications

Biodesulfurization of Dibenzothiophene by Microbial Cells Coated with Magnetite Nanoparticles

Biodesulfurization of Dibenzothiophene by Microbial Cells Coated with Magnetite Nanoparticles

Stabilization of water/gas oil emulsions by desulfurizing cells of Gordonia alkanivorans RIPI90A

Microbial Desulfurization of Gasoline in a Mycobacterium goodii X7B Immobilized-Cell System

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