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Sharma R, Singh J, Verma N. A novel spectrophotometric method for simultaneous estimation of dibenzothiophene and 2-hydroxybiphenyl in their mixed spectrum and its application in screening of specific biodesulfurizing microbes. 3 Biotech 2020; 10:153. [PMID: 32181115 DOI: 10.1007/s13205-020-2138-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 02/14/2020] [Indexed: 10/24/2022] Open
Abstract
The desulfurization of fuel is currently enforced to meet environmental legislation and prevent pollution. The use of specific biodesulfurizing microbes with a unique 4S pathway allows the desulfurization without compromising the quality of fuel. These specific microbes can be screened by the detection of 2-hydroxybiphenol (2-HBP) in desulfurizing mixture of dibenzothiophene (DBT). At present, colorimetric Gibb's assay is the most commonly employed screening method which requires a specific reagent, i.e., 2,6-dichloroquninone-4-chloramide. In the present study, a novel and simple spectrophotometric method was developed for the detection of 2-HBP for screening purpose based on dual wavelength method. The developed method facilitates the simultaneous analysis of DBT desulfurization and 2-HBP production in a sample by merely measuring the absorbance differences at two specified wavelengths, i.e., ΔA (λ 320-λ 247) for DBT and ΔA (λ 286-λ 324) for 2-HBP. The developed method was used to screen 57 microbes and two specific desulfurizing microbes Bacillus flexus MS-5 and Bacillus cereus BR-31 were selected based on 2-HBP production. The outcomes of developed method were validated by HPLC analysis. The strains MS-5 and BR-31 were employed in biodesulfurization and resulted in 54.88 ± 1.12% and 55.72 ± 1.32% desulfurization of 1.0 mM DBT, respectively. The developed method for screening of specific desulfurizing microbes does not require any specific reagent or sophisticated instrument in spite of being quick and reliable. The microbes selected by developed method exhibited excellent potential for biodesulfurization of fuel.
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Anteneh YS, Franco CMM. Whole Cell Actinobacteria as Biocatalysts. Front Microbiol 2019; 10:77. [PMID: 30833932 PMCID: PMC6387938 DOI: 10.3389/fmicb.2019.00077] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 01/15/2019] [Indexed: 12/25/2022] Open
Abstract
Production of fuels, therapeutic drugs, chemicals, and biomaterials using sustainable biological processes have received renewed attention due to increasing environmental concerns. Despite having high industrial output, most of the current chemical processes are associated with environmentally undesirable by-products which escalate the cost of downstream processing. Compared to chemical processes, whole cell biocatalysts offer several advantages including high selectivity, catalytic efficiency, milder operational conditions and low impact on the environment, making this approach the current choice for synthesis and manufacturing of different industrial products. In this review, we present the application of whole cell actinobacteria for the synthesis of biologically active compounds, biofuel production and conversion of harmful compounds to less toxic by-products. Actinobacteria alone are responsible for the production of nearly half of the documented biologically active metabolites and many enzymes; with the involvement of various species of whole cell actinobacteria such as Rhodococcus, Streptomyces, Nocardia and Corynebacterium for the production of useful industrial commodities.
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Affiliation(s)
- Yitayal Shiferaw Anteneh
- College of Medicine and Public Health, Medical Biotechnology, Flinders University, Bedford Park, SA, Australia
- Department of Medical Microbiology, College of Medicine, Addis Ababa University, Addis Ababa, Ethiopia
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Su T, Su J, Liu S, Zhang C, He J, Huang Y, Xu S, Gu L. Structural and Biochemical Characterization of BdsA from Bacillus subtilis WU-S2B, a Key Enzyme in the "4S" Desulfurization Pathway. Front Microbiol 2018; 9:231. [PMID: 29497411 PMCID: PMC5819316 DOI: 10.3389/fmicb.2018.00231] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 01/30/2018] [Indexed: 11/13/2022] Open
Abstract
Dibenzothiophene (DBT) and their derivatives, accounting for the major part of the sulfur components in crude oil, make one of the most significant pollution sources. The DBT sulfone monooxygenase BdsA, one of the key enzymes in the “4S” desulfurization pathway, catalyzes the oxidation of DBT sulfone to 2′-hydroxybiphenyl 2-sulfonic acid (HBPSi). Here, we determined the crystal structure of BdsA from Bacillus subtilis WU-S2B, at the resolution of 2.2 Å, and the structure of the BdsA-FMN complex at 2.4 Å. BdsA and the BdsA-FMN complex exist as tetramers. DBT sulfone was placed into the active site by molecular docking. Seven residues (Phe12, His20, Phe56, Phe246, Val248, His316, and Val372) are found to be involved in the binding of DBT sulfone. The importance of these residues is supported by the study of the catalytic activity of the active site variants. Structural analysis and enzyme activity assay confirmed the importance of the right position and orientation of FMN and DBT sulfone, as well as the involvement of Ser139 as a nucleophile in catalysis. This work combined with our previous structure of DszC provides a systematic structural basis for the development of engineered desulfurization enzymes with higher efficiency and stability.
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Affiliation(s)
- Tiantian Su
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, China
| | - Jing Su
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, China.,Faculty of Light Industry, Province Key Laboratory of Microbial Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Shiheng Liu
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, China
| | - Conggang Zhang
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, China
| | - Jing He
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, China
| | - Yan Huang
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, China
| | - Sujuan Xu
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, China
| | - Lichuan Gu
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, China
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Hino T, Hamamoto H, Suzuki H, Yagi H, Ohshiro T, Nagano S. Crystal structures of TdsC, a dibenzothiophene monooxygenase from the thermophile Paenibacillus sp. A11-2, reveal potential for expanding its substrate selectivity. J Biol Chem 2017; 292:15804-15813. [PMID: 28768765 DOI: 10.1074/jbc.m117.788513] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/23/2017] [Indexed: 11/06/2022] Open
Abstract
Sulfur compounds in fossil fuels are a major source of environmental pollution, and microbial desulfurization has emerged as a promising technology for removing sulfur under mild conditions. The enzyme TdsC from the thermophile Paenibacillus sp. A11-2 is a two-component flavin-dependent monooxygenase that catalyzes the oxygenation of dibenzothiophene (DBT) to its sulfoxide (DBTO) and sulfone (DBTO2) during microbial desulfurization. The crystal structures of the apo and flavin mononucleotide (FMN)-bound forms of DszC, an ortholog of TdsC, were previously determined, although the structure of the ternary substrate-FMN-enzyme complex remains unknown. Herein, we report the crystal structures of the DBT-FMN-TdsC and DBTO-FMN-TdsC complexes. These ternary structures revealed many hydrophobic and hydrogen-bonding interactions with the substrate, and the position of the substrate could reasonably explain the two-step oxygenation of DBT by TdsC. We also determined the crystal structure of the indole-bound enzyme because TdsC, but not DszC, can also oxidize indole, and we observed that indole binding did not induce global conformational changes in TdsC with or without bound FMN. We also found that the two loop regions close to the FMN-binding site are disordered in apo-TdsC and become structured upon FMN binding. Alanine substitutions of Tyr-93 and His-388, which are located close to the substrate and FMN bound to TdsC, significantly decreased benzothiophene oxygenation activity, suggesting their involvement in supplying protons to the active site. Interestingly, these substitutions increased DBT oxygenation activity by TdsC, indicating that expanding the substrate-binding site can increase the oxygenation activity of TdsC on larger sulfur-containing substrates, a property that should prove useful for future microbial desulfurization applications.
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Affiliation(s)
- Tomoya Hino
- From the Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyamacho-minami, Tottori 680-8552, Japan
| | - Haruka Hamamoto
- From the Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyamacho-minami, Tottori 680-8552, Japan
| | - Hirokazu Suzuki
- From the Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyamacho-minami, Tottori 680-8552, Japan
| | - Hisashi Yagi
- From the Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyamacho-minami, Tottori 680-8552, Japan
| | - Takashi Ohshiro
- From the Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyamacho-minami, Tottori 680-8552, Japan
| | - Shingo Nagano
- From the Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyamacho-minami, Tottori 680-8552, Japan
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Wang J, Butler RR, Wu F, Pombert JF, Kilbane JJ, Stark BC. Enhancement of Microbial Biodesulfurization via Genetic Engineering and Adaptive Evolution. PLoS One 2017; 12:e0168833. [PMID: 28060828 PMCID: PMC5218467 DOI: 10.1371/journal.pone.0168833] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 12/07/2016] [Indexed: 11/19/2022] Open
Abstract
In previous work from our laboratories a synthetic gene encoding a peptide (“Sulpeptide 1” or “S1”) with a high proportion of methionine and cysteine residues had been designed to act as a sulfur sink and was inserted into the dsz (desulfurization) operon of Rhodococcus erythropolis IGTS8. In the work described here this construct (dszAS1BC) and the intact dsz operon (dszABC) cloned into vector pRESX under control of the (Rhodococcus) kstD promoter were transformed into the desulfurization-negative strain CW25 of Rhodococcus qingshengii. The resulting strains (CW25[pRESX-dszABC] and CW25[pRESX-dszAS1BC]) were subjected to adaptive selection by repeated passages at log phase (up to 100 times) in minimal medium with dibenzothiophene (DBT) as sole sulfur source. For both strains DBT metabolism peaked early in the selection process and then decreased, eventually averaging four times that of the initial transformed cells; the maximum specific activity achieved by CW25[pRESX-dszAS1BC] exceeded that of CW25[pRESX-dszABC]. Growth rates increased by 7-fold (CW25[pRESX-dszABC]) and 13-fold (CW25[pRESX-dszAS1BC]) and these increases were stable. The adaptations of CW25[pRESX-dszAS1BC] were correlated with a 3-5X increase in plasmid copy numbers from those of the initial transformed cells; whole genome sequencing indicated that during its selection processes no mutations occurred to any of the dsz, S1, or other genes and promoters involved in sulfur metabolism, stress response, or DNA methylation, and that the effect of the sulfur sink produced by S1 is likely very small compared to the cells’ overall cysteine and methionine requirements. Nevertheless, a combination of genetic engineering using sulfur sinks and increasing Dsz capability with adaptive selection may be a viable strategy to increase biodesulfurization ability.
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Affiliation(s)
- Jia Wang
- Department of Biology, Illinois Institute of Technology, Chicago IL, United States of America
| | - Robert R. Butler
- Department of Biology, Illinois Institute of Technology, Chicago IL, United States of America
| | - Fan Wu
- Department of Biology, Illinois Institute of Technology, Chicago IL, United States of America
| | - Jean-François Pombert
- Department of Biology, Illinois Institute of Technology, Chicago IL, United States of America
| | - John J. Kilbane
- Department of Biology, Illinois Institute of Technology, Chicago IL, United States of America
| | - Benjamin C. Stark
- Department of Biology, Illinois Institute of Technology, Chicago IL, United States of America
- * E-mail:
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Complete Genome Sequences of Two Interactive Moderate Thermophiles, Paenibacillus napthalenovorans 32O-Y and Paenibacillus sp. 32O-W. GENOME ANNOUNCEMENTS 2016; 4:4/1/e01717-15. [PMID: 26868401 PMCID: PMC4751325 DOI: 10.1128/genomea.01717-15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Microorganisms with the capability to desulfurize petroleum are in high demand with escalating restrictions currently placed on fuel purity. Thermophilic desulfurizers are particularly valuable in high-temperature industrial applications. We report the whole-genome sequences of Paenibacillus napthalenovorans 32O-Y and Paenibacillus sp. 32O-W, which can and cannot, respectively, metabolize dibenzothiophene.
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Mohamed MES, Al-Yacoub ZH, Vedakumar JV. Biocatalytic desulfurization of thiophenic compounds and crude oil by newly isolated bacteria. Front Microbiol 2015; 6:112. [PMID: 25762990 PMCID: PMC4327732 DOI: 10.3389/fmicb.2015.00112] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 01/29/2015] [Indexed: 12/23/2022] Open
Abstract
Microorganisms possess enormous highly specific metabolic activities, which enable them to utilize and transform nearly every known chemical class present in crude oil. In this context, one of the most studied biocatalytic processes is the biodesulfurization (BDS) of thiophenic sulfur-containing compounds such as benzothiophene (BT) and dibenzothiophene (DBT) in crude oils and refinery streams. Three newly isolated bacterial strains, which were affiliated as Rhodococcus sp. strain SA11, Stenotrophomonas sp. strain SA21, and Rhodococcus sp. strain SA31, were enriched from oil contaminated soil in the presence of DBT as the sole S source. GC-FID analysis of DBT-grown cultures showed consumption of DBT, transient formation of DBT sulfone (DBTO2) and accumulation of 2-hydroxybiphenyl (2-HBP). Molecular detection of the plasmid-borne dsz operon, which codes for the DBT desulfurization activity, revealed the presence of dszA, dszB, and dszC genes. These results point to the operation of the known 4S pathway in the BDS of DBT. The maximum consumption rate of DBT was 11 μmol/g dry cell weight (DCW)/h and the maximum formation rate of 2-HBP formation was 4 μmol/g DCW/h. Inhibition of both cell growth and DBT consumption by 2-HBP was observed for all isolates but SA11 isolate was the least affected. The isolated biocatalysts desulfurized other model DBT alkylated homologs. SA11 isolate was capable of desulfurizing BT as well. Resting cells of SA11 exhibited 10% reduction in total sulfur present in heavy crude oil and 18% reduction in total sulfur present in the hexane-soluble fraction of the heavy crude oil. The capabilities of the isolated bacteria to survive and desulfurize a wide range of S compounds present in crude oil are desirable traits for the development of a robust BDS biocatalyst to upgrade crude oils and refinery streams.
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Affiliation(s)
| | - Zakariya H Al-Yacoub
- Biotechnology, Research and Development Center, Saudi Aramco, Dhahran Saudi Arabia
| | - John V Vedakumar
- Biotechnology, Research and Development Center, Saudi Aramco, Dhahran Saudi Arabia
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Derikvand P, Etemadifar Z. Improvement of Biodesulfurization Rate of Alginate Immobilized Rhodococcus erythropolis R1. Jundishapur J Microbiol 2014; 7:e9123. [PMID: 25147685 PMCID: PMC4138657 DOI: 10.5812/jjm.9123] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 01/28/2013] [Accepted: 03/03/2013] [Indexed: 12/03/2022] Open
Abstract
Background: Sulfur oxides released from the burning of oil causes severe environmental pollution. The sulfur can be removed via the 4S pathway in biodesulfurization (BDS). Immobilization approaches have been developed to prevent cell contamination of oil during the BDS process. Objectives: The encapsulation of Rhodococcus erythropolis R1 in calcium alginate beads was studied in order to enhance conversion of dibenzothiophene (DBT) to 2-hydroxy biphenyl (2-HBP) as the final product. Also the effect of different factors on the BDS process was investigated. Materials and Methods: Calcium alginate capsules were prepared using peristaltic pumps with different needle sizes to control the beads sizes. Scanning electron microscopy and flow cytometry methods were used to study the distribution and viability of encapsulated cells, respectively. Two non-ionic surfactants and also nano Ƴ-Al2O3were used with the ratio of 0.5% (v/v) and 1:5 (v/v) respectively to investigate their BDS efficiency. In addition, the effect of different bead sizes and different concentrations of sodium alginate in BDS activity was studied. Results: The 2% (w/v) sodium alginate beads with 1.5mm size were found to be the optimum for beads stability and efficient 2-HBP production. The viability of encapsulated cells decreased by 12% after 20 h of desulfurization, compared to free cells. Adding the non-ionic surfactants markedly enhanced the rate of BDS, because of increasing mass transfer of DBT to the gel matrix. In addition, Span 80 was more effective than Tween 80. The nanoƳ-Al2O3 particles could increase BDS rate by up to two-folds greater than that of the control beads. Conclusions: The nano Ƴ-Al2O3 can improve the immobilized biocatalyst for excellent efficiency of DBT desulfurization. Also the BDS activity can be enhanced by setting the other explained factors at optimum levels.
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Affiliation(s)
- Peyman Derikvand
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, IR Iran
| | - Zahra Etemadifar
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, IR Iran
- Corresponding author: Zahra Etemadifar, Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, IR Iran. Tel: +98-3117932367, Fax: +98-3117932456, E-mail:
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C-S targeted biodegradation of dibenzothiophene by Stenotrophomonas sp. NISOC-04. Appl Biochem Biotechnol 2011; 165:938-48. [PMID: 21750993 DOI: 10.1007/s12010-011-9310-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Accepted: 06/19/2011] [Indexed: 10/18/2022]
Abstract
Crude oil-contaminated soil samples were gathered across Khuzestan oilfields (National Iranian South Oil Company, NISOC) consequently experienced a screening procedure for isolating C-S targeted dibenzothiophene-biodegrading microorganisms with previously optimized techniques. Among the isolates, a bacterial strain was selected due to its capability of biodegrading dibenzothiophene in a C-S targeted manner in aqueous phases and medium mostly consisting of separately biphasic water-gasoline. The 16S rDNA of the isolate was amplified using eubacterial-specific primers and then sequenced. Based on sequence data analysis, the microorganism, designated NISOC-04, clustered most closely with the members of the genus Stenotrophomonas. Gas chromatography indicated that Stenotrophomonas sp. NISOC-04 utilizes 82% of starting 0.8 mM dibenzothiophene within a 48-h-long exponential growth phase. Growth curve analysis revealed the inability of Stenotrophomonas sp. NISOC-04 to utilize dibenzothiophene (DBT) as the exclusive carbon or carbon/sulfur source. Gibbs' assay showed no 2-hydroxy biphenyl accumulation, but HPLC confirmed the presence of 2-hydroxy biphenyl as the final product of DBT desulfurization. Under sulfur starvation, Stenotrophomonas sp. NISOC-04 produced a huge biomass with untraceable sulfur and utilized atmospheric insignificant sulfur levels.
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Bhatia S, Sharma D. Biodesulfurization of dibenzothiophene, its alkylated derivatives and crude oil by a newly isolated strain Pantoea agglomerans D23W3. Biochem Eng J 2010. [DOI: 10.1016/j.bej.2010.04.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Novel reactivity of dibenzothiophene monooxygenase from Bacillus subtilis WU-S2B. Biosci Biotechnol Biochem 2009; 73:2128-30. [PMID: 19734655 DOI: 10.1271/bbb.90284] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Dibenzothiophene monooxygenase (BdsC) from Bacillus subtilis WU-S2B utilized aromatic compounds not having sulfur atoms as substrates. It acted on indole and its derivatives to form indigoid pigments, and also utilized indoline and phenoxazine. In addition, BdsC exhibited activity toward benzothiophene (BT) derivatives but not BT, suggesting that it shows wide reactivity toward aromatic compounds.
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Alcon A, Martin A, Santos V, Gomez E, Garcia-Ochoa F. Kinetic model for DBT desulphurization by resting whole cells of Pseudomonas putida CECT5279. Biochem Eng J 2008. [DOI: 10.1016/j.bej.2007.11.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Santos V, Galdeano C, Gomez E, Alcon A, Garcia-Ochoa F. Oxygen uptake rate measurements both by the dynamic method and during the process growth of Rhodococcus erythropolis IGTS8: Modelling and difference in results. Biochem Eng J 2006. [DOI: 10.1016/j.bej.2006.09.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Srinivasaraghavan K, Sarma PM, Lal B. Comparative analysis of phenotypic and genotypic characteristics of two desulfurizing bacterial strains, Mycobacterium phlei SM120-1 and Mycobacterium phlei GTIS10. Lett Appl Microbiol 2006; 42:483-9. [PMID: 16620207 DOI: 10.1111/j.1472-765x.2006.01842.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM To compare few phenotypic and genotypic characteristics of two desulfurizing bacterial strains, Mycobacterium phlei SM120-1 and Mycobacterium phlei GTIS10. METHODS AND RESULTS In the present study, dibenzothiophene (DBT) desulfurizing activity, composition of fatty acids of cell membranes, DBT sulfone monoxygenase gene (bdsA) and the selection pressure applied during the growth and enrichment of the bacterial strains M. phlei SM120-1 and M. phlei GTIS10 were compared in our laboratory. The DBT desulfurization activity of M. phlei SM120-1 was found to be 0.17 +/- 0.02 micromol 2-HBP min(-1) (gram dry cell weight)(-1) and that of the bacterial strain M. phlei GTIS10 was 1.09 +/- 0.05 micromol 2-HBP min(-1) (gram dry cell weight)(-1). Fatty acid methyl ester analysis of cell membranes of these two bacterial strains in the presence of light gas oil showed that both the strains had different fatty acid profiles in their cell membranes. Comparison of the full gene sequences of the desulfurization gene bdsA in the two bacterial strains showed significant difference in the bdsA gene sequences. There was a significant difference observed in the selection pressure applied during the growth and enrichment of the two bacterial strains. CONCLUSIONS The results of the comparative study of the bacterial strains, M. phlei SM120-1 and M. phlei GTIS10 showed that there were considerable differences in the phenotypic and genotypic characteristics of these two strains. SIGNIFICANCE AND IMPACT OF STUDY The present study would broaden the understanding of biodesulfurization trait at intra-species level.
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Affiliation(s)
- K Srinivasaraghavan
- Center of Bioresources and Biotechnology, TERI school of Advanced Studies, New Delhi, India
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Rashtchi M, Mohebali G, Akbarnejad M, Towfighi J, Rasekh B, Keytash A. Analysis of biodesulfurization of model oil system by the bacterium, strain RIPI-22. Biochem Eng J 2006. [DOI: 10.1016/j.bej.2005.08.034] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Modeling the production of a Rhodococcus erythropolis IGTS8 biocatalyst for DBT biodesulfurization: Influence of media composition. Enzyme Microb Technol 2005. [DOI: 10.1016/j.enzmictec.2004.06.016] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Van Hamme JD, Fedorak PM, Foght JM, Gray MR, Dettman HD. Use of a novel fluorinated organosulfur compound to isolate bacteria capable of carbon-sulfur bond cleavage. Appl Environ Microbiol 2004; 70:1487-93. [PMID: 15006770 PMCID: PMC368330 DOI: 10.1128/aem.70.3.1487-1493.2004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The vacuum residue fraction of heavy crudes contributes to the viscosity of these oils. Specific microbial cleavage of C-S bonds in alkylsulfide bridges that form linkages in this fraction may result in dramatic viscosity reduction. To date, no bacterial strains have been shown conclusively to cleave C-S bonds within alkyl chains. Screening for microbes that can perform this activity was greatly facilitated by the use of a newly synthesized compound, bis-(3-pentafluorophenylpropyl)-sulfide (PFPS), as a novel sulfur source. The terminal pentafluorinated aromatic rings of PFPS preclude growth of aromatic ring-degrading bacteria but allow for selective enrichment of strains capable of cleaving C-S bonds. A unique bacterial strain, Rhodococcus sp. strain JVH1, that used PFPS as a sole sulfur source was isolated from an oil-contaminated environment. Gas chromatography-mass spectrometry analysis revealed that JVH1 oxidized PFPS to a sulfoxide and then a sulfone prior to cleaving the C-S bond to form an alcohol and, presumably, a sulfinate from which sulfur could be extracted for growth. Four known dibenzothiophene-desulfurizing strains, including Rhodococcus sp. strain IGTS8, were all unable to cleave the C-S bond in PFPS but could oxidize PFPS to the sulfone via the sulfoxide. Conversely, JVH1 was unable to oxidize dibenzothiophene but was able to use a variety of alkyl sulfides, in addition to PFPS, as sole sulfur sources. Overall, PFPS is an excellent tool for isolating bacteria capable of cleaving subterminal C-S bonds within alkyl chains. The type of desulfurization displayed by JVH1 differs significantly from previously described reaction results.
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Abbad-Andaloussi S, Lagnel C, Warzywoda M, Monot F. Multi-criteria comparison of resting cell activities of bacterial strains selected for biodesulfurization of petroleum compounds. Enzyme Microb Technol 2003. [DOI: 10.1016/s0141-0229(02)00320-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Kirimura K, Furuya T, Sato R, Ishii Y, Kino K, Usami S. Biodesulfurization of naphthothiophene and benzothiophene through selective cleavage of carbon-sulfur bonds by Rhodococcus sp. strain WU-K2R. Appl Environ Microbiol 2002; 68:3867-72. [PMID: 12147483 PMCID: PMC124047 DOI: 10.1128/aem.68.8.3867-3872.2002] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Naphtho[2,1-b]thiophene (NTH) is an asymmetric structural isomer of dibenzothiophene (DBT), and in addition to DBT derivatives, NTH derivatives can also be detected in diesel oil following hydrodesulfurization treatment. Rhodococcus sp. strain WU-K2R was newly isolated from soil for its ability to grow in a medium with NTH as the sole source of sulfur, and growing cells of WU-K2R degraded 0.27 mM NTH within 7 days. WU-K2R could also grow in the medium with NTH sulfone, benzothiophene (BTH), 3-methyl-BTH, or 5-methyl-BTH as the sole source of sulfur but could not utilize DBT, DBT sulfone, or 4,6-dimethyl-DBT. On the other hand, WU-K2R did not utilize NTH or BTH as the sole source of carbon. By gas chromatography-mass spectrometry analysis, desulfurized NTH metabolites were identified as NTH sulfone, 2'-hydroxynaphthylethene, and naphtho[2,1-b]furan. Moreover, since desulfurized BTH metabolites were identified as BTH sulfone, benzo[c][1,2]oxathiin S-oxide, benzo[c][1,2]oxathiin S,S-dioxide, o-hydroxystyrene, 2-(2'-hydroxyphenyl)ethan-1-al, and benzofuran, it was concluded that WU-K2R desulfurized NTH and BTH through the sulfur-specific degradation pathways with the selective cleavage of carbon-sulfur bonds. Therefore, Rhodococcus sp. strain WU-K2R, which could preferentially desulfurize asymmetric heterocyclic sulfur compounds such as NTH and BTH through the sulfur-specific degradation pathways, is a unique desulfurizing biocatalyst showing properties different from those of DBT-desulfurizing bacteria.
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Affiliation(s)
- Kohtaro Kirimura
- Department of Applied Chemistry, School of Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 169-8555, Japan.
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