Degradation and desulfurization of dibenzothiophene sulfone and other sulfur compounds by Agrobacterium MC501 and a mixed culture

Recent advances in molecular biology have extended our understanding of the metabolic processes related to microbial transformation of petroleum hydrocarbons. The physiological responses of microorganisms to the presence of hydrocarbons, including cell surface alterations and adaptive mechanisms for uptake and efflux of these substrates, have been characterized. New molecular techniques have enhanced our ability to investigate the dynamics of microbial communities in petroleum-impacted ecosystems. By establishing conditions which maximize rates and extents of microbial growth, hydrocarbon access, and transformation, highly accelerated and bioreactor-based petroleum waste degradation processes have been implemented. Biofilters capable of removing and biodegrading volatile petroleum contaminants in air streams with short substrate-microbe contact times (<60 s) are being used effectively. Microbes are being injected into partially spent petroleum reservoirs to enhance oil recovery. However, these microbial processes have not exhibited consistent and effective performance, primarily because of our inability to control conditions in the subsurface environment. Microbes may be exploited to break stable oilfield emulsions to produce pipeline quality oil. There is interest in replacing physical oil desulfurization processes with biodesulfurization methods through promotion of selective sulfur removal without degradation of associated carbon moieties. However, since microbes require an environment containing some water, a two-phase oil-water system must be established to optimize contact between the microbes and the hydrocarbon, and such an emulsion is not easily created with viscous crude oil. This challenge may be circumvented by application of the technology to more refined gasoline and diesel substrates, where aqueous-hydrocarbon emulsions are more easily generated. Molecular approaches are being used to broaden the substrate specificity and increase the rates and extents of desulfurization. Bacterial processes are being commercialized for removal of H2S and sulfoxides from petrochemical waste streams. Microbes also have potential for use in removal of nitrogen from crude oil leading to reduced nitric oxide emissions provided that technical problems similar to those experienced in biodesulfurization can be solved. Enzymes are being exploited to produce added-value products from petroleum substrates, and bacterial biosensors are being used to analyze petroleum-contaminated environments

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“…Other aerobic selective desulfurizing microbes include Nocardia spp., Agrobacterium sp. strain MC501 (130), Mycobacterium spp. (452), Gordona sp.…”

Section: Microbial Desulfurizationmentioning

confidence: 99%

Recent Advances in Petroleum Microbiology

Hamme¹,

Singh

Ward

2003

Microbiol Mol Biol Rev

1,193

640

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“…Other DBT-desulphurizing isolates have been classified as Agrobacterium strain MC501 (Constanti et al, 1996), Mycobacterium strain G3 (Nekodzuka et al, 1997) and Paenibacillus strain All-2 (Konishi et al, 1997). All of these isolates are reported to desulphurize DBT to HBP, but are otherwise poorly characterized.…”

Section: Introductionmentioning

confidence: 99%

Isolation of a unique benzothiophene-desulphurizing bacterium, Gordona sp. strain 213E (NCIMB 40816), and characterization of the desulphurization pathway

Gilbert¹,

Morton²,

Buchanan³

et al. 1998

Microbiology

107

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Gordona sp. strain 213E (NCIMB 40816) grew in pure culture in a mineral salts medium containing fructose as a source of carbon and energy, and benzothiophene (BTH) as the sole source of sulphur. During growth a phenolic compound accumulated, as indicated by the production of a blue colour on addition of Gibb's reagent. Therefore this pathway is analogous to the dibenzothiophene (DBT) desulphurization pathway of Rhodococcus sp. strain IGTS8, in which 2-hydroxybiphenyl accumulates during growth with DBT as the sole sulphur source. Ethyl acetate extraction of the culture medium yielded the metabolites benzothiophene S-oxide (BTHO), benzothiophene S,S-dioxide (BTHO2), benzo[c][1,2]oxathiin 6-oxide (BcOTO), 2-(2'-hydroxyphenyl)ethan 1-al (HPEal) and benzofuran (BFU). The deduced pathway for BTH desulphurization is BTH ? BTHO ? BTHO2 ? HPESi- ? HPEal. HPESi- is (Z)-2-(2'-hydroxyphenyl)ethen 1-sulphinate, the stable aqueous-solution form of BcOTO. It was concluded that HPEal was the Gibb's-reagent-reactive phenolic compound which accumulated in the culture medium of strain 213E during growth, and that the presence of BFU was due to partial condensation of HPEal during the ethyl acetate extraction procedure. Gordona sp. strain 213E was unable to grow in a mineral salts medium containing fructose as a source of carbon and energy and DBT as the sole sulphur source. BTH-desulphurization-active cells (grown using BTH as sole sulphur source) were unable to desulphurize DBT. Likewise Rhodococcus sp. strain IGTS8 was unable to grow using BTH as the sole sulphur source, and DBT-desulphurization-active cells of strain IGTS8 (grown using DBT as sole sulphur source) were unable to desulphurize BTH. This absence of cross-reactivity is discussed in terms of fundamental differences in the chemistry of the DBT- and BTH-desulphurization reactions.

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“…The gasoline oxygenate MTBE (99.8%) was obtained from Sigma-Aldrich Chemical Company. The composition of the mineral medium (MM) used for isolate cultivation was: KH 2 PO 4 1 g/l, MgCl 2 Á6H 2 O 1 g/l, NH 4 Cl 2 g/l, CaCl 2 0.001 mg/l, FeSO 4 Á7H 2 O 0.001 g/l (Constantí et al 1996), supplemented with yeast extract (0.5-0.1 g/l), MTBE (100 mg/l) or agar (20 g/l) when needed.…”

Section: Methodsmentioning

confidence: 99%

Biodegradation of methyl tert-butyl ether by newly identified soil microorganisms in a simple mineral solution

Barberà

Mateo

Monkaityte

et al. 2010

World J Microbiol Biotechnol

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Methyl tert-butyl ether (MTBE) is a widely used fuel ether, which has become a soil and water contaminant. In this study, 12 microbial strains were isolated from gasoline-contaminated soils and selected because of their capacity to grow in MTBE. The strains were identified by 16S/ITS rDNA gene sequencing and screened for their ability to consume MTBE aerobically in a simple mineral solution. Solid phase microoextraction and gas chromatography were used to detect MTBE degradation. High levels of MTBE biodegradation were obtained using resting cells of the bacteria Achromobacter xylosoxidans MCM1/1 (78%), Enterobacter cloacae MCM2/1 (50%), and Ochrobactrum anthropi MCM5/1 (52%) and the fungus Exophiala dermatitidis MCM3/4 (14%). Our phylogenetic analysis clearly shows that bacterial MTBE biodegraders belong to the clade of Proteobacteria. For further insight, MTBE-degrader strains were profiled by denaturing gel gradient electrophoresis (DGGE) of PCRamplified 16S rRNA gene sequences. This approach could be used to analyse microbial community dynamics in bioremediation processes.

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Degradation and desulfurization of dibenzothiophene sulfone and other sulfur compounds by Agrobacterium MC501 and a mixed culture

Cited by 39 publications

References 16 publications

Recent Advances in Petroleum Microbiology

Recent Advances in Petroleum Microbiology

Isolation of a unique benzothiophene-desulphurizing bacterium, Gordona sp. strain 213E (NCIMB 40816), and characterization of the desulphurization pathway

Biodegradation of methyl tert-butyl ether by newly identified soil microorganisms in a simple mineral solution

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