1
|
Chen Y, Ren H, Kong X, Wu H, Lu Z. A multicomponent propane monooxygenase catalyzes the initial degradation of methyl tert-butyl ether in Mycobacterium vaccae JOB5. Appl Environ Microbiol 2023; 89:e0118723. [PMID: 37823642 PMCID: PMC10617536 DOI: 10.1128/aem.01187-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 08/30/2023] [Indexed: 10/13/2023] Open
Abstract
Methyl tert-butyl ether (MTBE) has been recognized as a groundwater contaminant due to its widespread distribution and potential threat to human health. The limited understanding of the enzymes catalyzing MTBE degradation restricts their application in MTBE bioremediation. In this study, an MTBE-degrading soluble di-iron monooxygenase that clusters phylogenetically with a known propane monooxygenase (PRM) encoded by the prmABCD gene cluster was identified and functionally characterized, revealing their role in MTBE metabolism by Mycobacterium vaccae JOB5. Transcriptome analysis demonstrated that the expression of prmABCD was upregulated when JOB5 was induced by MTBE. Escherichia coli Rosetta heterologously expressing prmABCD from JOB5 could transform MTBE, indicating that the PRM of JOB5 is capable of the initial degradation of MTBE. The loss of the gene encoding the oxygenase α-subunit or β-subunit, the coupling protein, or the reductase disrupted MTBE transformation by the recombinant E. coli Rosetta. In addition, the catalytic capacity of PRM is likely affected by residue G95 in the active site pocket and residues I84, P165, A269, and V270 in the substrate tunnel structure. Mutation of amino acids in the active site and substrate tunnel resulted in inefficiency or inactivation of MTBE degradation, and the activity in 1,4-dioxane (1,4-D) degradation was diminished less than that in MTBE degradation.IMPORTANCEMulticomponent monooxygenases catalyzing the initial hydroxylation of MTBE are important in MTBE biodegradation. Previous studies of MTBE degradation enzymes have focused on P450s, alkane monooxygenase and MTBE monooxygenase, but the vital role of soluble di-iron monooxygenases has rarely been reported. In this study, we deciphered the essential catalytic role of a PRM and revealed the key residues of the PRM in MTBE metabolism. Our findings provide new insight into the MTBE-degrading gene cluster and enzymes in bacteria. This characterization of the PRM associated with MTBE degradation expands our understanding of MTBE-degrading gene diversity and provides a novel candidate enzyme for the bioremediation of MTBE-contaminated sites.
Collapse
Affiliation(s)
- Yiyang Chen
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- Cancer Center, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hao Ren
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- Cancer Center, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiangyu Kong
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- Cancer Center, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hao Wu
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- Cancer Center, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zhenmei Lu
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- Cancer Center, Zhejiang University, Hangzhou, Zhejiang, China
| |
Collapse
|
2
|
Huizenga JM, Semprini L. Influence of growth substrate and contaminant mixtures on the degradation of BTEX and MTBE by Rhodococcus rhodochrous ATCC strain 21198. Biodegradation 2023; 34:461-475. [PMID: 37329399 PMCID: PMC10803100 DOI: 10.1007/s10532-023-10037-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 05/30/2023] [Indexed: 06/19/2023]
Abstract
The degradation of the prevalent environmental contaminants benzene, toluene, ethylbenzene, and xylenes (BTEX) along with a common co-contaminant methyl tert-butyl ether (MTBE) by Rhodococcus rhodochrous ATCC Strain 21198 was investigated. The ability of 21198 to degrade these contaminants individually and in mixtures was evaluated with resting cells grown on isobutane, 1-butanol, and 2-butanol. Growth of 21198 in the presence of BTEX and MTBE was also studied to determine the growth substrate that best supports simultaneous microbial growth and contaminants degradation. Cells grown on isobutane, 1-butanol, and 2-butanol were all capable of degrading the contaminants, with isobutane grown cells exhibiting the most rapid degradation rates and 1-butanol grown cells exhibiting the slowest. However, in conditions where BTEX and MTBE were present during microbial growth, 1-butanol was determined to be an effective substrate for supporting concurrent growth and contaminant degradation. Contaminant degradation was found to be a combination of metabolic and cometabolic processes. Evidence for growth of 21198 on benzene and toluene is presented along with a possible transformation pathway. MTBE was cometabolically transformed to tertiary butyl alcohol, which was also observed to be transformed by 21198. This work demonstrates the possible utility of primary and secondary alcohols to support biodegradation of monoaromatic hydrocarbons and MTBE. Furthermore, the utility of 21198 for bioremediation applications has been expanded to include BTEX and MTBE.
Collapse
Affiliation(s)
- Juliana M Huizenga
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, 105 SW 26th St, Corvallis, OR, 97331, USA
| | - Lewis Semprini
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, 105 SW 26th St, Corvallis, OR, 97331, USA.
| |
Collapse
|
3
|
Mahor D, Cong Z, Weissenborn MJ, Hollmann F, Zhang W. Valorization of Small Alkanes by Biocatalytic Oxyfunctionalization. CHEMSUSCHEM 2022; 15:e202101116. [PMID: 34288540 DOI: 10.1002/cssc.202101116] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/18/2021] [Indexed: 06/13/2023]
Abstract
The oxidation of alkanes into valuable chemical products is a vital reaction in organic synthesis. This reaction, however, is challenging, owing to the inertness of C-H bonds. Transition metal catalysts for C-H functionalization are frequently explored. Despite chemical alternatives, nature has also evolved powerful oxidative enzymes (e. g., methane monooxygenases, cytochrome P450 oxygenases, peroxygenases) that are capable of transforming C-H bonds under very mild conditions, with only the use of molecular oxygen or hydrogen peroxide as electron acceptors. Although progress in alkane oxidation has been reviewed extensively, little attention has been paid to small alkane oxidation. The latter holds great potential for the manufacture of chemicals. This Minireview provides a concise overview of the most relevant enzyme classes capable of small alkanes (C<6 ) oxyfunctionalization, describes the essentials of the catalytic mechanisms, and critically outlines the current state-of-the-art in preparative applications.
Collapse
Affiliation(s)
- Durga Mahor
- National Innovation Center for Synthetic Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- Indian Institute of Science Education and Research Berhampur, Odisha, 760010, India
| | - Zhiqi Cong
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences, Qingdao, Shandong, 266101, P. R. China
| | - Martin J Weissenborn
- Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle, Saale), Germany
| | - Frank Hollmann
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ, Delft, The Netherlands
| | - Wuyuan Zhang
- National Innovation Center for Synthetic Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
| |
Collapse
|
4
|
Li S, Wang D, Du D, Qian K, Yan W. Characterization of co-metabolic biodegradation of methyl tert-butyl ether by a Acinetobacter sp. strain. RSC Adv 2019; 9:38962-38972. [PMID: 35540635 PMCID: PMC9076015 DOI: 10.1039/c9ra09507a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 11/20/2019] [Indexed: 11/21/2022] Open
Abstract
Co-metabolic bioremediation is a promising approach for the elimination of methyl tert-butyl ether (MTBE), which is a common pollutant found worldwide in ground water. In this paper, a bacterial strain able to co-metabolically degrade MTBE was isolated and named as Acinetobacter sp. SL3 based on 16S rRNA gene sequencing analysis. Strain SL3 could grow on n-alkanes (C5–C8) accompanied with the co-metabolic degradation of MTBE. The number of carbons present in the n-alkane substrate significantly influenced the degradation rate of MTBE and accumulation of tert-butyl alcohol (TBA), with n-octane resulting in a higher MTBE degradation rate (Vmax = 36.7 nmol min−1 mgprotein−1, Ks = 6.4 mmol L−1) and lower TBA accumulation rate. A degradation experiment in a fed-batch reactor revealed that the efficiency of MTBE degradation by Acinetobacter sp. strain SL3 did not show an obvious decrease after nine rounds of MTBE replenishment ranging from 0.1–0.5 mmol L−1. The results of this paper reveal the preferable properties of Acinetobacter sp. SL3 for the bioremediation of MTBE via co-metabolism and leads towards the development of new MTBE elimination technologies. Acinetobacter sp. SL3 could co-metabolically degrade MTBE when grown on n-alkanes. An extremely low TBA accumulation were achieved on n-octane. The fed-batch reactor degradation revealed continuous MTBE degradation capacity by Acinetobacter sp. SL3.![]()
Collapse
Affiliation(s)
- Shanshan Li
- Department of Environmental Science & Engineering
- Xi'an Jiaotong University
- Xi'an
- China
| | - Dan Wang
- Department of Environmental Science & Engineering
- Xi'an Jiaotong University
- Xi'an
- China
| | - Dan Du
- Department of Environmental Science & Engineering
- Xi'an Jiaotong University
- Xi'an
- China
| | - Keke Qian
- Department of Environmental Science & Engineering
- Xi'an Jiaotong University
- Xi'an
- China
| | - Wei Yan
- Department of Environmental Science & Engineering
- Xi'an Jiaotong University
- Xi'an
- China
| |
Collapse
|
5
|
Biodegradation of Methyl tert-Butyl Ether by Co-Metabolism with a Pseudomonas sp. Strain. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 13:ijerph13090883. [PMID: 27608032 PMCID: PMC5036716 DOI: 10.3390/ijerph13090883] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/17/2016] [Accepted: 08/30/2016] [Indexed: 11/24/2022]
Abstract
Co-metabolic bioremediation is supposed to be an impressive and promising approach in the elimination technology of methyl tert-butyl ether (MTBE), which was found to be a common pollutant worldwide in the ground or underground water in recent years. In this paper, bacterial strain DZ13 (which can co-metabolically degrade MTBE) was isolated and named as Pseudomonas sp. DZ13 based on the result of 16S rRNA gene sequencing analysis. Strain DZ13 could grow on n-alkanes (C5-C8), accompanied with the co-metabolic degradation of MTBE. Diverse n-alkanes with different carbon number showed a significant influence on the degradation rate of MTBE and accumulation of tert-butyl alcohol (TBA). When Pseudomonas sp. DZ13 co-metabolically degraded MTBE with n-pentane as the growth substrate, a higher MTBE-degrading rate (Vmax = 38.1 nmol/min/mgprotein, Ks = 6.8 mmol/L) and lower TBA-accumulation was observed. In the continuous degradation experiment, the removal efficiency of MTBE by Pseudomonas sp. Strain DZ13 did not show an obvious decrease after five times of continuous addition.
Collapse
|
6
|
Bennett K, Sadler NC, Wright AT, Yeager C, Hyman MR. Activity-Based Protein Profiling of Ammonia Monooxygenase in Nitrosomonas europaea. Appl Environ Microbiol 2016; 82:2270-2279. [PMID: 26826234 PMCID: PMC4959501 DOI: 10.1128/aem.03556-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 01/27/2016] [Indexed: 11/20/2022] Open
Abstract
Nitrosomonas europaea is an aerobic nitrifying bacterium that oxidizes ammonia (NH3) to nitrite (NO2 (-)) through the sequential activities of ammonia monooxygenase (AMO) and hydroxylamine dehydrogenase (HAO). Many alkynes are mechanism-based inactivators of AMO, and here we describe an activity-based protein profiling method for this enzyme using 1,7-octadiyne (17OD) as a probe. Inactivation of NH4 (+)-dependent O2 uptake by N. europaea by 17OD was time- and concentration-dependent. The effects of 17OD were specific for ammonia-oxidizing activity, andde novoprotein synthesis was required to reestablish this activity after cells were exposed to 17OD. Cells were reacted with Alexa Fluor 647 azide using a copper-catalyzed azide-alkyne cycloaddition (CuAAC) (click) reaction, solubilized, and analyzed by SDS-PAGE and infrared (IR) scanning. A fluorescent 28-kDa polypeptide was observed for cells previously exposed to 17OD but not for cells treated with either allylthiourea or acetylene prior to exposure to 17OD or for cells not previously exposed to 17OD. The fluorescent polypeptide was membrane associated and aggregated when heated with β-mercaptoethanol and SDS. The fluorescent polypeptide was also detected in cells pretreated with other diynes, but not in cells pretreated with structural homologs containing a single ethynyl functional group. The membrane fraction from 17OD-treated cells was conjugated with biotin-azide and solubilized in SDS. Streptavidin affinity-purified polypeptides were on-bead trypsin-digested, and amino acid sequences of the peptide fragments were determined by liquid chromatography-mass spectrometry (LC-MS) analysis. Peptide fragments from AmoA were the predominant peptides detected in 17OD-treated samples. In-gel digestion and matrix-assisted laser desorption ionization-tandem time of flight (MALDI-TOF/TOF) analyses also confirmed that the fluorescent 28-kDa polypeptide was AmoA.
Collapse
Affiliation(s)
- Kristen Bennett
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, USA
| | - Natalie C Sadler
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Aaron T Wright
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Chris Yeager
- Biosciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Michael R Hyman
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, USA
| |
Collapse
|
7
|
Li S, Li D, Yan W. Cometabolism of methyl tert-butyl ether by a new microbial consortium ERS. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:10196-10205. [PMID: 25697553 DOI: 10.1007/s11356-015-4211-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 02/04/2015] [Indexed: 06/04/2023]
Abstract
The release of methyl tert-butyl-ether (MTBE) into the environment has increased the worldwide concern about the pollution of MTBE. In this paper, a microbial consortium was isolated from the soil sample near an oil station, which can degrade MTBE directly with a low biomass yield and MTBE degrading efficiency. Further research has indicated that this consortium can degrade MTBE efficiently when grown on n-octane as the cometabolic substrate. The results of 16S rDNA based on phylogenetic analysis of the selected operating taxonomic units (OTUs) involved in the consortium revealed that one OTU was related to Pseudomonas putida GPo1, which could cometabolically degrade MTBE on the growth of n-octane. This may help explain why n-octane could be the optimal cometabolic substrate of the consortium for MTBE degradation. Furthermore, the degradation of MTBE was observed along with the consumption of n-octane. Different K s values for MTBE were observed for cells grown with or without n-octane, suggesting that different enzymes are responsible for the oxidation of MTBE in cells grown on n-octane or MTBE. The results are discussed in terms of their impacts on our understanding of MTBE biodegradation and cometabolism.
Collapse
Affiliation(s)
- Shanshan Li
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China
| | | | | |
Collapse
|
8
|
Bravo AL, Sigala JC, Le Borgne S, Morales M. Expression of an alkane monooxygenase (alkB) gene and methyl tert-butyl ether co-metabolic oxidation in Pseudomonas citronellolis. Biotechnol Lett 2014; 37:807-14. [DOI: 10.1007/s10529-014-1737-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 11/20/2014] [Indexed: 11/30/2022]
|
9
|
Lee DG, Chu KH. Effects of growth substrate on triclosan biodegradation potential of oxygenase-expressing bacteria. CHEMOSPHERE 2013; 93:1904-1911. [PMID: 23890965 DOI: 10.1016/j.chemosphere.2013.06.069] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 06/10/2013] [Accepted: 06/24/2013] [Indexed: 06/02/2023]
Abstract
Triclosan is an antimicrobial agent, an endocrine disrupting compound, and an emerging contaminant in the environment. This is the first study investigating triclosan biodegradation potential of four oxygenase-expressing bacteria: Rhodococcus jostii RHA1, Mycobacterium vaccae JOB5, Rhodococcus ruber ENV425, and Burkholderia xenovorans LB400. B. xenovorans LB400 and R. ruber ENV425 were unable to degrade triclosan. Propane-grown M. vaccae JOB5 can completely degrade triclosan (5 mg L(-1)). R. jostii RHA1 grown on biphenyl, propane, and LB medium with dicyclopropylketone (DCPK), an alkane monooxygenase inducer, was able to degrade the added triclosan (5 mg L(-1)) to different extents. Incomplete degradation of triclosan by RHA1 is probably due to triclosan product toxicity. The highest triclosan transformation capacity (Tc, defined as the amount of triclosan degraded/the number of cells inactivated; 5.63×10(-3) ng triclosan/16S rRNA gene copies) was observed for biphenyl-grown RHA1 and the lowest Tc (0.20×10(-3) ng-triclosan/16S rRNA gene copies) was observed for propane-grown RHA1. No triclosan degradation metabolites were detected during triclosan degradation by propane- and LB+DCPK-grown RHA1. When using biphenyl-grown RHA1 for degradation, four chlorinated metabolites (2,4-dichlorophenol, monohydroxy-triclosan, dihydroxy-triclosan, and 2-chlorohydroquinone (a new triclosan metabolite)) were detected. Based on the detected metabolites, a meta-cleavage pathway was proposed for triclosan degradation.
Collapse
Affiliation(s)
- Do Gyun Lee
- Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843-3136, USA
| | | |
Collapse
|
10
|
Enhanced biodegradation of methyl tert-butyl-ether by a microbial consortium. Curr Microbiol 2013; 68:317-23. [PMID: 24162446 DOI: 10.1007/s00284-013-0480-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 09/15/2013] [Indexed: 10/26/2022]
Abstract
The widespread use of Methyl tert-butyl-ether (MTBE) as a gasoline additive has resulted in a higher detection rate of MTBE in groundwater systems. Therefore, the researchers show more concern about the bioremediation of MTBE-impacted aquifers. In this paper, a MTBE-direct-degrading bacterial consortium was enriched (named RS1) and further studied. In order to identify the microbial community of the consortium, 17 and 12 different single strains were isolated from nutrient medium and MSM media (with MTBE as the sole carbon source), respectively. 16S rDNA-based phylogenetic analysis revealed that these diverse bacteria belonged to 14 genera, in which Pseudomonas was dominant. Several strains which can grow with MTBE as the sole carbon and energy source were also identified, such as M1, related to MTBE-degrading Arthrobacter sp. ATCC27778. Furthermore, the appropriate addition of certain single strain in consortium RS1 (M1:RS1 = 1:2) facilitates MTBE degradation by increasing the quantity of efficient MTBE-degrading bacteria. This work will provide microbial source and theoretical fundament for further bioremediation of MTBE-contaminated aquifers, which has applied potential and environmental importance.
Collapse
|
11
|
Key KC, Sublette KL, Duncan K, Mackay DM, Scow KM, Ogles D. Using DNA-Stable Isotope Probing to Identify MTBE- and TBA-Degrading Microorganisms in Contaminated Groundwater. GROUND WATER MONITORING & REMEDIATION 2013; 33:57-68. [PMID: 25525320 PMCID: PMC4267322 DOI: 10.1111/gwmr.12031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Although the anaerobic biodegradation of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) has been documented in the laboratory and the field, knowledge of the microorganisms and mechanisms involved is still lacking. In this study, DNA-stable isotope probing (SIP) was used to identify microorganisms involved in anaerobic fuel oxygenate biodegradation in a sulfate-reducing MTBE and TBA plume. Microorganisms were collected in the field using Bio-Sep® beads amended with 13C5-MTBE, 13C1-MTBE (only methoxy carbon labeled), or13C4-TBA. 13C-DNA and 12C-DNA extracted from the Bio-Sep beads were cloned and 16S rRNA gene sequences were used to identify the indigenous microorganisms involved in degrading the methoxy group of MTBE and the tert-butyl group of MTBE and TBA. Results indicated that microorganisms were actively degrading 13C-labeled MTBE and TBA in situ and the 13C was incorporated into their DNA. Several sequences related to known MTBE- and TBA-degraders in the Burkholderiales and the Sphingomonadales orders were detected in all three13C clone libraries and were likely to be primary degraders at the site. Sequences related to sulfate-reducing bacteria and iron-reducers, such as Geobacter and Geothrix, were only detected in the clone libraries where MTBE and TBA were fully labeled with 13C, suggesting that they were involved in processing carbon from the tert-butyl group. Sequences similar to the Pseudomonas genus predominated in the clone library where only the methoxy carbon of MTBE was labeled with 13C. It is likely that members of this genus were secondary degraders cross-feeding on 13C-labeled metabolites such as acetate.
Collapse
Affiliation(s)
- Katherine C. Key
- Department of Chemical Engineering, University of Tulsa, Tulsa, OK, USA
| | - Kerry L. Sublette
- Department of Chemical Engineering, University of Tulsa, Tulsa, OK, USA
| | - Kathleen Duncan
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK
| | - Douglas M. Mackay
- Department of Land, Air, and Water Resources, University of California at Davis, Davis, CA
| | - Kate M. Scow
- Department of Land, Air, and Water Resources, University of California at Davis, Davis, CA
| | | |
Collapse
|
12
|
Rosell M, Gonzalez-Olmos R, Rohwerder T, Rusevova K, Georgi A, Kopinke FD, Richnow HH. Critical evaluation of the 2D-CSIA scheme for distinguishing fuel oxygenate degradation reaction mechanisms. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:4757-4766. [PMID: 22455373 DOI: 10.1021/es2036543] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Although the uniform initial hydroxylation of methyl tert-butyl ether (MTBE) and other oxygenates during aerobic biodegradation has already been proven by molecular tools, variations in carbon and hydrogen enrichment factors (ε(C) and ε(H)) have still been associated with different reaction mechanisms (McKelvie et al. Environ. Sci. Technol. 2009, 43, 2793-2799). Here, we present new laboratory-derived ε(C) and ε(H) data on the initial degradation mechanisms of MTBE, ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME) by chemical oxidation (permanganate, Fenton reagents), acid hydrolysis, and aerobic bacteria cultures (species of Aquincola, Methylibium, Gordonia, Mycobacterium, Pseudomonas, and Rhodococcus). Plotting of Δδ(2)H/ Δδ(13)C data from chemical oxidation and hydrolysis of ethers resulted in slopes (Λ values) of 22 ± 4 and between 6 and 12, respectively. With A. tertiaricarbonis L108, R. zopfii IFP 2005, and Gordonia sp. IFP 2009, ε(C) was low (<|-1|‰) and ε(H) was insignificant. Fractionation obtained with P. putida GPo1 was similar to acid hydrolysis and M. austroafricanum JOB5 and R. ruber DSM 7511 displayed Λ values previously only ascribed to anaerobic attack. The fractionation patterns rather correlate with the employment of different P450, AlkB, and other monooxygenases, likely catalyzing ether hydroxylation via different transition states. Our data questions the value of 2D-CSIA for a simple distinguishing of oxygenate biotransformation mechanisms, therefore caution and complementary tools are needed for proper interpretation of groundwater plumes at field sites.
Collapse
Affiliation(s)
- Mònica Rosell
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig, Germany.
| | | | | | | | | | | | | |
Collapse
|
13
|
Salazar M, Morales M, Revah S. Biodegradation of methyl tert-butyl ether by cometabolism with hexane in biofilters inoculated with Pseudomonas aeruginosa. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2012; 47:1017-1026. [PMID: 22486671 DOI: 10.1080/10934529.2012.667319] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Biodegradation of methyl tert-butyl ether (MTBE) vapors by cometabolism with gaseous hexane (n-hexane > 95%) was investigated using Pseudomonas aeruginosa utilizing short chain aliphatic hydrocarbon (C(5)-C(8)). Kinetic batch experiments showed that MTBE was degraded even when hexane was completely exhausted with a cometabolic coefficient of 1.06 ± 0.16 mg MTBE mg hexane(-1). Intermediate tert-butyl alcohol (TBA) accumulation was observed followed by its gradual consumption. A maximum MTBE elimination capacity (EC(MAX)) of 35 g m(-3) h(-1) and removal efficiency (RE) of 70% were attained in mineral medium amended biofilters having an empty bed residence time (EBRT) of 1 min. For these experimental conditions, a maximum hexane EC of approximately 60 g m(-3) h(-1) was obtained at a load of 75 g m(-3) h(-1). Experiments under transient conditions revealed a competitive substrate interaction between MTBE and hexane. Biomass densities between 5.8 and 12.6 g L(biofilter) (-1) were obtained. Nevertheless, production of biopolymers caused non-uniform distribution flow rates that reduced the performance. Residence time distribution profiles showed an intermediate dispersion flow rate with a dispersion coefficient of 0.8 cm(2) s(-1).
Collapse
Affiliation(s)
- Margarita Salazar
- Universidad Autónoma Metropolitana-Cuajimalpa, Departamento de Procesos y Tecnología, México, Distrito Federal, México
| | | | | |
Collapse
|
14
|
Chen SC, Chen CS, Zhan KV, Yang KH, Chien CC, Shieh BS, Chen WM. Biodegradation of methyl tert-butyl ether (MTBE) by Enterobacter sp. NKNU02. JOURNAL OF HAZARDOUS MATERIALS 2011; 186:1744-1750. [PMID: 21227585 DOI: 10.1016/j.jhazmat.2010.12.079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 11/27/2010] [Accepted: 12/15/2010] [Indexed: 05/30/2023]
Abstract
We previously isolated and identified Enterobacter sp. NKNU02 as a methyl tert-butyl ether (MTBE)-degrading bacterial strain from gasoline-contaminated water. In this study, tert-butyl alcohol, acetic acid, 2-propanol, and propenoic acid were detected using gas chromatography/mass spectrometry when MTBE was degraded by rest cells of Enterobacter sp. NKNU02 cells. We also found that biodegradation of MTBE was decreased, but not totally inhibited in mixtures of benzene, toluene, ethylbenzene and xylene. The effects of MTBE on the biology of Enterobacter sp. NKNU02 were elucidated using 2D proteomic analysis. The cytoplasmic proteins isolated from these MTBE-treated and -untreated cells were carried out for proteomic analysis. Results showed that there were 6 differential protein spots and 8 differential protein spots, respectively, as compared to their corresponding control (without MTBE addition), at the indicated incubation times when 40% and 60% of 100 mg/L of MTBE had been removed, Among these proteins, nine were successfully identified with matrix-assisted laser desorption ionization-time of flight-mass spectrometry. Proteins identified included extracellular solute-binding protein, periplasmic-binding protein ytfQ, cationic amino acid ABC transporter, isocitrate dehydrogenase, cysteine synthase A, alkyl hydroperoxide reductase (AhpC), transaldolase, and alcohol dehydrogenase. Based on these differential proteins, we discuss the bacterial responses to MTBE at the molecular level.
Collapse
Affiliation(s)
- Ssu Ching Chen
- Department of Life Sciences, National Central University, Jhongli City, Taoyuan County, Taiwan.
| | | | | | | | | | | | | |
Collapse
|
15
|
Identification of tertiary butyl alcohol (TBA)-utilizing organisms in BioGAC reactors using 13C-DNA stable isotope probing. Biodegradation 2011; 22:961-72. [DOI: 10.1007/s10532-011-9455-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 01/10/2011] [Indexed: 11/26/2022]
|
16
|
Biodegradation of methyl tert-butyl ether by newly identified soil microorganisms in a simple mineral solution. World J Microbiol Biotechnol 2010. [DOI: 10.1007/s11274-010-0522-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
17
|
Smith CA, Hyman MR. Oxidation of gasoline oxygenates by closely related non-haem-iron alkane hydroxylases in Pseudomonas mendocina KR1 and other n-octane-utilizing Pseudomonas strains. ENVIRONMENTAL MICROBIOLOGY REPORTS 2010; 2:426-432. [PMID: 23766116 DOI: 10.1111/j.1758-2229.2010.00155.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Pseudomonas mendocina KR1 oxidizes the gasoline oxygenate methyl tertiary butyl ether (MTBE) to tertiary butyl alcohol (TBA) during growth on C5 -C8 n-alkanes. We have further explored oxidation of ether oxygenates by this strain to help identify the enzyme that catalyses these reactions. High levels of MTBE-oxidizing activity occurred in resting cells grown on C5 -C8 n-alkanes. Lower activities occurred in cells grown on longer-chain n-alkanes (C9 -C11 ) and 1°-alcohols (C5 -C10 ). N-octane-grown cells also oxidized tertiary amyl methyl ether (TAME) to tertiary amyl alcohol (TAA), but did not oxidize ethyl tertiary butyl ether (ETBE), TBA or TAA. A 39 kDa polypeptide in whole cell extracts of n-octane-grown cells strongly cross-reacted with an anti-AlkB polyclonal antiserum in an SDS-PAGE/immunoblot. This polypeptide was absent or less abundant in cells grown on dextrose, dextrose plus dicyclopropylketone or 1-octanol. N-octane-grown cells of Pseudomonas aeruginosa strains KSLA-473 and ATCC 17423 oxidized MTBE and TAME but not ETBE. N-hexadecane-grown cells of these strains and strain PAO1 did not oxidize any of the oxygenates tested. Our results indicate ether oxygenate-degrading activity in alkane-utilizing pseudomonads is consistently observed with close homologues of the GPo1 non-haem-iron alkane hydroxylases but is otherwise not a consistent catalytic feature of these diverse enzymes.
Collapse
Affiliation(s)
- Christy A Smith
- Department of Microbiology, North Carolina State University, Raleigh, NC 27607, USA
| | | |
Collapse
|
18
|
Eixarch H, Constantí M. Biodegradation of MTBE by Achromobacter xylosoxidans MCM1/1 induces synthesis of proteins that may be related to cell survival. Process Biochem 2010. [DOI: 10.1016/j.procbio.2009.12.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
19
|
House AJ, Hyman MR. Effects of gasoline components on MTBE and TBA cometabolism by Mycobacterium austroafricanum JOB5. Biodegradation 2009; 21:525-41. [DOI: 10.1007/s10532-009-9321-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 11/26/2009] [Indexed: 11/28/2022]
|
20
|
Morales M, Nava V, Velásquez E, Razo-Flores E, Revah S. Mineralization of methyl tert-butyl ether and other gasoline oxygenates by Pseudomonads using short n-alkanes as growth source. Biodegradation 2008; 20:271-80. [PMID: 18814038 DOI: 10.1007/s10532-008-9219-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Accepted: 09/05/2008] [Indexed: 12/01/2022]
Abstract
Biodegradation of methyl tert-butyl ether (MTBE) by cometabolism has shown to produce recalcitrant metabolic intermediates that often accumulate. In this work, a consortium containing Pseudomonads was studied for its ability to fully degrade oxygenates by cometabolism. This consortium mineralized MTBE and TBA with C3-C7 n-alkanes. The highest degradation rates for MTBE (75 +/- 5 mg g(protein) (-1) h(-1)) and TBA (86.9 +/- 7.3 mg g(protein) (-1) h(-1)) were obtained with n-pentane and n-propane, respectively. When incubated with radiolabeled MTBE and n-pentane, it converted more than 96% of the added MTBE to (14)C-CO(2). Furthermore, the consortium degraded tert-amyl methyl ether, tert-butyl alcohol (TBA), tert-amyl alcohol, ethyl tert-butyl ether (ETBE) when n-pentane was used as growth source. Three Pseudomonads were isolated but only two showed independent MTBE degradation activity. The maximum degradation rates were 101 and 182 mg g(protein) (-1) h(-1) for Pseudomonas aeruginosa and Pseudomonas citronellolis, respectively. The highest specific affinity (a degrees (MTBE)) value of 4.39 l g(protein) (-1) h(-1) was obtained for Pseudomonas aeruginosa and complete mineralization was attained with a MTBE: n-pentane ratio (w/w) of 0.7. This is the first time that Pseudomonads have been reported to fully mineralize MTBE by cometabolic degradation.
Collapse
Affiliation(s)
- Marcia Morales
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Artificios # 40 Col Miguel Hidalgo, Mexico, DF, Mexico.
| | | | | | | | | |
Collapse
|
21
|
Involvement of a novel enzyme, MdpA, in methyl tert-butyl ether degradation in Methylibium petroleiphilum PM1. Appl Environ Microbiol 2008; 74:6631-8. [PMID: 18791002 DOI: 10.1128/aem.01192-08] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methylibium petroleiphilum PM1 is a well-characterized environmental strain capable of complete metabolism of the fuel oxygenate methyl tert-butyl ether (MTBE). Using a molecular genetic system which we established to study MTBE metabolism by PM1, we demonstrated that the enzyme MdpA is involved in MTBE removal, based on insertional inactivation and complementation studies. MdpA is constitutively expressed at low levels but is strongly induced by MTBE. MdpA is also involved in the regulation of tert-butyl alcohol (TBA) removal under certain conditions but is not directly responsible for TBA degradation. Phylogenetic comparison of MdpA to related enzymes indicates close homology to the short-chain hydrolyzing alkane hydroxylases (AH1), a group that appears to be a distinct subfamily of the AHs. The unique, substrate-size-determining residue Thr(59) distinguishes MdpA from the AH1 subfamily as well as from AlkB enzymes linked to MTBE degradation in Mycobacterium austroafricanum.
Collapse
|
22
|
Biodegradability of 2-ethylhexyl nitrate (2-EHN), a cetane improver of diesel oil. Biodegradation 2008; 20:85-94. [DOI: 10.1007/s10532-008-9202-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Accepted: 06/11/2008] [Indexed: 10/21/2022]
|
23
|
Skinner KM, Martinez-Prado A, Hyman MR, Williamson KJ, Ciuffetti LM. Pathway, inhibition and regulation of methyl tertiary butyl ether oxidation in a filamentous fungus, Graphium sp. Appl Microbiol Biotechnol 2008; 77:1359-65. [DOI: 10.1007/s00253-007-1268-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Revised: 10/29/2007] [Accepted: 10/29/2007] [Indexed: 11/29/2022]
|
24
|
Schäfer F, Breuer U, Benndorf D, von Bergen M, Harms H, Müller R. Growth ofAquincola tertiaricarbonis L108 ontert-Butyl Alcohol Leads to the Induction of a Phthalate Dioxygenase-related Protein and its Associated Oxidoreductase Subunit. Eng Life Sci 2007. [DOI: 10.1002/elsc.200700011] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
25
|
Hristova KR, Schmidt R, Chakicherla AY, Legler TC, Wu J, Chain PS, Scow KM, Kane SR. Comparative transcriptome analysis of Methylibium petroleiphilum PM1 exposed to the fuel oxygenates methyl tert-butyl ether and ethanol. Appl Environ Microbiol 2007; 73:7347-57. [PMID: 17890343 PMCID: PMC2168209 DOI: 10.1128/aem.01604-07] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
High-density whole-genome cDNA microarrays were used to investigate substrate-dependent gene expression of Methylibium petroleiphilum PM1, one of the best-characterized aerobic methyl tert-butyl ether (MTBE)-degrading bacteria. Differential gene expression profiling was conducted with PM1 grown on MTBE and ethanol as sole carbon sources. Based on microarray high scores and protein similarity analysis, an MTBE regulon located on the megaplasmid was identified for further investigation. Putative functions for enzymes encoded in this regulon are described with relevance to the predicted MTBE degradation pathway. A new unique dioxygenase enzyme system that carries out the hydroxylation of tert-butyl alcohol to 2-methyl-2-hydroxy-1-propanol in M. petroleiphilum PM1 was discovered. Hypotheses regarding the acquisition and evolution of MTBE genes as well as the involvement of IS elements in these complex processes were formulated. The pathways for toluene, phenol, and alkane oxidation via toluene monooxygenase, phenol hydroxylase, and propane monooxygenase, respectively, were upregulated in MTBE-grown cells compared to ethanol-grown cells. Four out of nine putative cyclohexanone monooxygenases were also upregulated in MTBE-grown cells. The expression data allowed prediction of several hitherto-unknown enzymes of the upper MTBE degradation pathway in M. petroleiphilum PM1 and aided our understanding of the regulation of metabolic processes that may occur in response to pollutant mixtures and perturbations in the environment.
Collapse
Affiliation(s)
- Krassimira R Hristova
- Department of Land Air and Water Resources, Plant and Environmental Sciences Building, University of California, Davis, Davis, CA 95616.
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Lopes Ferreira N, Mathis H, Labbé D, Monot F, Greer CW, Fayolle-Guichard F. n-Alkane assimilation and tert-butyl alcohol (TBA) oxidation capacity in Mycobacterium austroafricanum strains. Appl Microbiol Biotechnol 2007; 75:909-19. [PMID: 17347817 DOI: 10.1007/s00253-007-0892-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Revised: 02/09/2007] [Accepted: 02/11/2007] [Indexed: 11/27/2022]
Abstract
Mycobacterium austroafricanum IFP 2012, which grows on methyl tert-butyl ether (MTBE) and on tert-butyl alcohol (TBA), the main intermediate of MTBE degradation, also grows on a broad range of n-alkanes (C2 to C16). A single alkB gene copy, encoding a non-heme alkane monooxygenase, was partially amplified from the genome of this bacterium. Its expression was induced after growth on n-propane, n-hexane, n-hexadecane and on TBA but not after growth on LB. The capacity of other fast-growing mycobacteria to grow on n-alkanes (C1 to C16) and to degrade TBA after growth on n-alkanes was compared to that of M. austroafricanum IFP 2012. We studied M. austroafricanum IFP 2012 and IFP 2015 able to grow on MTBE, M. austroafricanum IFP 2173 able to grow on isooctane, Mycobacterium sp. IFP 2009 able to grow on ethyl tert-butyl ether (ETBE), M. vaccae JOB5 (M. austroaafricanum ATCC 29678) able to degrade MTBE and TBA and M. smegmatis mc2 155 with no known degradation capacity towards fuel oxygenates. The M. austroafricanum strains grew on a broad range of n-alkanes and three were able to degrade TBA after growth on propane, hexane and hexadecane. An alkB gene was partially amplified from the genome of all mycobacteria and a sequence comparison demonstrated a close relationship among the M. austroafricanum strains. This is the first report suggesting the involvement of an alkane hydroxylase in TBA oxidation, a key step during MTBE metabolism.
Collapse
|
27
|
Kane SR, Chakicherla AY, Chain PSG, Schmidt R, Shin MW, Legler TC, Scow KM, Larimer FW, Lucas SM, Richardson PM, Hristova KR. Whole-genome analysis of the methyl tert-butyl ether-degrading beta-proteobacterium Methylibium petroleiphilum PM1. J Bacteriol 2007; 189:1931-45. [PMID: 17158667 PMCID: PMC1855728 DOI: 10.1128/jb.01259-06] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Accepted: 11/29/2006] [Indexed: 11/20/2022] Open
Abstract
Methylibium petroleiphilum PM1 is a methylotroph distinguished by its ability to completely metabolize the fuel oxygenate methyl tert-butyl ether (MTBE). Strain PM1 also degrades aromatic (benzene, toluene, and xylene) and straight-chain (C(5) to C(12)) hydrocarbons present in petroleum products. Whole-genome analysis of PM1 revealed an approximately 4-Mb circular chromosome and an approximately 600-kb megaplasmid, containing 3,831 and 646 genes, respectively. Aromatic hydrocarbon and alkane degradation, metal resistance, and methylotrophy are encoded on the chromosome. The megaplasmid contains an unusual t-RNA island, numerous insertion sequences, and large repeated elements, including a 40-kb region also present on the chromosome and a 29-kb tandem repeat encoding phosphonate transport and cobalamin biosynthesis. The megaplasmid also codes for alkane degradation and was shown to play an essential role in MTBE degradation through plasmid-curing experiments. Discrepancies between the insertion sequence element distribution patterns, the distributions of best BLASTP hits among major phylogenetic groups, and the G+C contents of the chromosome (69.2%) and plasmid (66%), together with comparative genome hybridization experiments, suggest that the plasmid was recently acquired and apparently carries the genetic information responsible for PM1's ability to degrade MTBE. Comparative genomic hybridization analysis with two PM1-like MTBE-degrading environmental isolates (approximately 99% identical 16S rRNA gene sequences) showed that the plasmid was highly conserved (ca. 99% identical), whereas the chromosomes were too diverse to conduct resequencing analysis. PM1's genome sequence provides a foundation for investigating MTBE biodegradation and exploring the genetic regulation of multiple biodegradation pathways in M. petroleiphilum and other MTBE-degrading beta-proteobacteria.
Collapse
Affiliation(s)
- Staci R Kane
- Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
|
29
|
|
30
|
Kotani T, Kawashima Y, Yurimoto H, Kato N, Sakai Y. Gene structure and regulation of alkane monooxygenases in propane-utilizing Mycobacterium sp. TY-6 and Pseudonocardia sp. TY-7. J Biosci Bioeng 2006; 102:184-92. [PMID: 17046531 DOI: 10.1263/jbb.102.184] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Accepted: 05/30/2006] [Indexed: 11/17/2022]
Abstract
Mycobacterium sp. TY-6 and Pseudonocardia sp. TY-7 were isolated from soil samples as propane-utilizing bacteria and were found to be able to utilize various gaseous and liquid n-alkanes as carbon and energy sources. One gene cluster, M-prmABCD, and two gene clusters, P-prm1ABCD and P-prm2ABCD, were cloned from the genomes of Mycobacterium sp. TY-6 and Pseudonocardia sp. TY-7, respectively. These gene clusters are homologous to the gene cluster encoding the multicomponent propane monooxygenase (prmABCD) of Gordonia sp. TY-5. The expression of prm gene clusters in Mycobacterium sp. TY-6 and Pseudonocardia sp. TY-7 was shown to be induced by gaseous n-alkanes (C2-C4) except methane, suggesting that the products of these genes are involved in gaseous n-alkane oxidation. Homologous genes for an alkane hydroxylase system (alk system) involved in liquid n-alkane oxidation were also cloned from the genomic DNA of Mycobacterium sp. TY-6. The alk gene cluster was transcribed in response to liquid n-alkanes (C11-C15). These results indicate that Mycobacterium sp. TY-6 has two distinct gene clusters for multicomponent monooxygenases involved in alkane oxidation. Whole-cell reactions revealed that propane is oxidized to 1-propanol through terminal oxidation in Mycobacterium sp. TY-6 and that propane is oxidized to 1-propanol and 2-propanol through both terminal and subterminal oxidations in Pseudonocardia sp. TY-7. This study reveals the diversity of propane metabolism present in microorganisms.
Collapse
Affiliation(s)
- Tetsuya Kotani
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake, Kyoto, Japan
| | | | | | | | | |
Collapse
|
31
|
Lopes Ferreira N, Malandain C, Fayolle-Guichard F. Enzymes and genes involved in the aerobic biodegradation of methyl tert-butyl ether (MTBE). Appl Microbiol Biotechnol 2006; 72:252-62. [PMID: 16804692 DOI: 10.1007/s00253-006-0494-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Revised: 05/04/2006] [Accepted: 05/04/2006] [Indexed: 10/24/2022]
Abstract
Fuel oxygenates, mainly methyl tert-butyl ether (MTBE) but also ethyl tert-butyl ether (ETBE), are added to gasoline in replacement of lead tetraethyl to enhance its octane index. Their addition also improves the combustion efficiency and therefore decreases the emission of pollutants (CO and hydrocarbons). On the other hand, MTBE, being highly soluble in water and recalcitrant to biodegradation, is a major pollutant of water in aquifers contaminated by MTBE-supplemented gasoline during accidental release. MTBE was shown to be degraded through cometabolic oxidation or to be used as a carbon and energy source by a few microorganisms. We have summarized the present state of knowledge about the microorganisms involved in MTBE degradation and the MTBE catabolic pathways. The role of the different enzymes is discussed as well as the rare and recent data concerning the genes encoding the enzymes involved in the MTBE pathway. The phylogeny of the microorganisms isolated for their capacity to grow on MTBE is also described.
Collapse
Affiliation(s)
- Nicolas Lopes Ferreira
- Biotechnology and Biomass Chemistry Department, Institut Français du Pétrole, 1-4 avenue de Bois-Préau, 92852, Rueil-Malmaison, France
| | | | | |
Collapse
|
32
|
Ferreira NL, Labbé D, Monot F, Fayolle-Guichard F, Greer CW. Genes involved in the methyl tert-butyl ether (MTBE) metabolic pathway of Mycobacterium austroafricanum IFP 2012. Microbiology (Reading) 2006; 152:1361-1374. [PMID: 16622053 DOI: 10.1099/mic.0.28585-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Methyltert-butyl ether (MTBE) is a persistent pollutant of surface and groundwater, and the reasons for its low biodegradability are poorly documented. Using one of the rare bacterial strains able to grow in the presence of MTBE,Mycobacterium austroafricanumIFP 2012, the protein profiles of crude extracts after growth in the presence of MTBE and glucose were compared by SDS-PAGE. Ten proteins with molecular masses of 67, 64, 63, 55, 50, 27, 24, 17, 14 and 11 kDa were induced after growth in the presence of MTBE. Partial amino acid sequences of N-terminal and internal peptide fragments of the 64 kDa protein were used to design degenerate oligonucleotide primers to amplify total DNA by PCR, yielding a DNA fragment that was used as a probe for cloning. A two-step cloning procedure was performed to obtain a 10 327 bp genomic DNA fragment containing seven ORFs, including a putative regulator,mpdR, and four genes,mpdC,orf1,mpdBandorf2, in the same cluster. The MpdB protein (64 kDa) was related to a flavoprotein of the glucose–methanol–choline oxidoreductase family, and the MpdC protein (55 kDa) showed a high similarity with NAD(P) aldehyde dehydrogenases. Heterologous expression of these gene products was performed inMycobacterium smegmatismc2 155. The recombinant strain was able to degrade an intermediate of MTBE biodegradation, 2-methyl 1,2-propanediol, to hydroxyisobutyric acid. This is believed to be the first report of the cloning and characterization of a cluster of genes specifically involved in the MTBE biodegradation pathway ofM. austroafricanumIFP 2012.
Collapse
MESH Headings
- Bacterial Proteins/analysis
- Bacterial Proteins/isolation & purification
- Biodegradation, Environmental
- Cloning, Molecular
- DNA, Bacterial/chemistry
- DNA, Bacterial/genetics
- Electrophoresis, Polyacrylamide Gel
- Flavoproteins/genetics
- Gene Expression Regulation, Bacterial
- Genes, Bacterial
- Glucose/metabolism
- Hydroxybutyrates/metabolism
- Methyl Ethers/metabolism
- Molecular Sequence Data
- Molecular Weight
- Mycobacterium/genetics
- Mycobacterium/growth & development
- Mycobacterium/metabolism
- Mycobacterium smegmatis/genetics
- Mycobacterium smegmatis/metabolism
- Open Reading Frames
- Oxidoreductases/genetics
- Propylene Glycols/metabolism
- Proteome/analysis
- Proteome/isolation & purification
- Sequence Analysis, DNA
- Sequence Analysis, Protein
- Sequence Homology, Amino Acid
Collapse
Affiliation(s)
- Nicolas Lopes Ferreira
- Biotechnology Research Institute, NRCC, 6100 Royalmount Avenue, Montreal, Quebec, Canada H4P2R2
- Institut Français du Pétrole, 1-4, avenue de Bois-Préau, F-92852 Rueil-Malmaison, France
| | - Diane Labbé
- Biotechnology Research Institute, NRCC, 6100 Royalmount Avenue, Montreal, Quebec, Canada H4P2R2
| | - Frédéric Monot
- Institut Français du Pétrole, 1-4, avenue de Bois-Préau, F-92852 Rueil-Malmaison, France
| | | | - Charles W Greer
- Biotechnology Research Institute, NRCC, 6100 Royalmount Avenue, Montreal, Quebec, Canada H4P2R2
| |
Collapse
|
33
|
Abstract
Propane and n-butane inhibit methyl tertiary butyl ether oxidation by n-alkane-grown Pseudomonas putida GPo1. Here we demonstrate that these gases are oxidized by this strain and support cell growth. Both gases induced alkane hydroxylase activity and appear to be oxidized by the same enzyme system used for the oxidation of n-octane.
Collapse
Affiliation(s)
- Erika L Johnson
- Department of Microbiology, North Carolina State University, Raleigh, NC 27695-7615, USA
| | | |
Collapse
|