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Oakley CE, Barton TS, Oakley BR. Identification of the chaA and fwA Spore Color Genes of Aspergillus nidulans. J Fungi (Basel) 2024; 10:104. [PMID: 38392776 PMCID: PMC10890192 DOI: 10.3390/jof10020104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 02/24/2024] Open
Abstract
Wild-type Aspergillus nidulans asexual spores (conidia) are green due to a pigment that protects the spores against ultraviolet light. The pigment is produced by a biosynthetic pathway, the genes of which are dispersed in the genome. The backbone molecule of the pigment is a polyketide synthesized by a polyketide synthase encoded by the wA gene. If wA is not functional, the conidia are white. The polyketide is modified by a laccase encoded by the yA gene and inactivation of yA in an otherwise wild-type background results in yellow spores. Additional spore color mutations have been isolated and mapped to a locus genetically, but the genes that correspond to these loci have not been determined. Spore color markers have been useful historically, and they remain valuable in the molecular genetics era. One can determine if a transforming fragment has been successfully integrated at the wA or yA locus by simply looking at the color of transformant conidia. The genes of the potentially useful color loci chaA (chartreuse conidia) and fwA (fawn conidia) have not been identified previously. We chose a set of candidate genes for each locus by comparing the assembled genome with the genetic map. By systematically deleting these candidate genes, we identified a cytochrome P450 gene (AN10028) corresponding to chaA. Deletions of this gene result in chartreuse conidia and chartreuse mutations can be complemented in trans by a functional copy of this gene. With fwA, we found that the existing fawn mutation, fwA1, is a deletion of 2241 base pairs that inactivates three genes. By deleting each of these genes, we determined that fwA is AN1088, an EthD domain protein. Deletion of AN1088 results in fawn conidia as expected. Neither deletion of chaA nor fwA restricts growth and both should be valuable target loci for transformations. Combinations of deletions have allowed us to investigate the epistasis relationships of wA, yA, chaA and fwA.
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Affiliation(s)
- C Elizabeth Oakley
- Department of Molecular Biosciences, University of Kansas, 1200 Sunnyside Ave., Lawrence, KS 66045, USA
| | - Thomas S Barton
- Department of Molecular Biosciences, University of Kansas, 1200 Sunnyside Ave., Lawrence, KS 66045, USA
| | - Berl R Oakley
- Department of Molecular Biosciences, University of Kansas, 1200 Sunnyside Ave., Lawrence, KS 66045, USA
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Zhang ST, Li T, Deng SK, Spain JC, Zhou NY. A cytochrome P450 system initiates 4-nitroanisole degradation in Rhodococcus sp. strain JS3073. JOURNAL OF HAZARDOUS MATERIALS 2023; 458:131886. [PMID: 37348368 DOI: 10.1016/j.jhazmat.2023.131886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/13/2023] [Accepted: 06/16/2023] [Indexed: 06/24/2023]
Abstract
Nitroanisoles are used widely as synthetic intermediates and explosives. Although bacteria have been reported to degrade 4-nitroanisole (4NA) under aerobic conditions, the key enzymes and the catalytic mechanism have remained elusive. Rhodococcus sp. strain JS3073 was isolated for its ability to grow on 4NA as the sole carbon and energy source. In this study, whole cell biotransformation experiments indicated that 4NA degradation is initiated by O-demethylation to form 4-nitrophenol (PNP), which undergoes subsequent degradation by a previously established pathway involving formation of 1,2,4-benzenetriol and release of nitrite. Based on comparative transcriptomics and heterologous expression, a novel three-component cytochrome P450 system encoded by pnaABC initiates the O-demethylation of 4NA to yield formaldehyde and PNP. The pnaABC genes encode a phthalate dioxygenase type reductase (PnaA), a cytochrome P450 monooxygenase (PnaB), and an EthD family protein (PnaC) with putative function similar to ferredoxins. This unusual P450 system also has a broad substrate specificity for nitroanisole derivatives. Sequence analysis of PnaAB revealed high identity with multiple self-sufficient P450s of the CYP116B subfamily. The findings revealed the molecular basis of the catabolic pathway for 4NA initiated by an unusual O-demethylase PnaABC and extends the understanding of the diversity among P450s and their electron transport chains.
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Affiliation(s)
- Shu-Ting Zhang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Tao Li
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shi-Kai Deng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jim C Spain
- Center for Environmental Diagnostics and Bioremediation, University of West Florida, 11000 University Parkway, Pensacola, FL 32514-5751, USA
| | - Ning-Yi Zhou
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
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Parthasarathy A, Miranda RR, Eddingsaas NC, Chu J, Freezman IM, Tyler AC, Hudson AO. Polystyrene Degradation by Exiguobacterium sp. RIT 594: Preliminary Evidence for a Pathway Containing an Atypical Oxygenase. Microorganisms 2022; 10:microorganisms10081619. [PMID: 36014041 PMCID: PMC9416434 DOI: 10.3390/microorganisms10081619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/06/2022] [Accepted: 08/07/2022] [Indexed: 11/16/2022] Open
Abstract
The widespread use of plastics has led to their increasing presence in the environment and subsequent pollution. Some microorganisms degrade plastics in natural ecosystems and the associated metabolic pathways can be studied to understand the degradation mechanisms. Polystyrene (PS) is one of the more recalcitrant plastic polymers that is degraded by only a few bacteria. Exiguobacterium is a genus of Gram-positive poly-extremophilic bacteria known to degrade PS, thus being of biotechnological interest, but its biochemical mechanisms of degradation have not yet been elucidated. Based solely on genome annotation, we initially proposed PS degradation by Exiguobacterium sp. RIT 594 via depolymerization and epoxidation catalyzed by a ring epoxidase. However, Fourier transform infrared (FTIR) spectroscopy analysis revealed an increase of carboxyl and hydroxyl groups with biodegradation, as well as of unconjugated C-C double bonds, both consistent with dearomatization of the styrene ring. This excludes any aerobic pathways involving side chain epoxidation and/or hydroxylation. Subsequent experiments confirmed that molecular oxygen is critical to PS degradation by RIT 594 because degradation ceased under oxygen-deprived conditions. Our studies suggest that styrene breakdown by this bacterium occurs via the sequential action of two enzymes encoded in the genome: an orphan aromatic ring-cleaving dioxygenase and a hydrolase.
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Affiliation(s)
- Anutthaman Parthasarathy
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY 14623, USA
- School of Chemistry and Biosciences, University of Bradford, Bradford BD7 1DP, UK
| | - Renata Rezende Miranda
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - Nathan C. Eddingsaas
- School of Chemistry and Materials Science, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - Jonathan Chu
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - Ian M. Freezman
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - Anna C. Tyler
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - André O. Hudson
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY 14623, USA
- Correspondence: ; Tel.: +1-585-475-4259
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Wang X, Lu H, Li Q, Zhou Y, Zhou J. Comparative genome and transcriptome of Rhodococcus pyridinivorans GF3 for analyzing the detoxification mechanism of anthraquinone compounds. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 237:113545. [PMID: 35453018 DOI: 10.1016/j.ecoenv.2022.113545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 04/15/2022] [Accepted: 04/17/2022] [Indexed: 06/14/2023]
Abstract
Anthraquinone compounds (ACs) could be efficiently degraded and detoxified by bacteria. However, the molecular mechanism of bacterial degradation and detoxification of ACs remains unclear. In this study, 1-aminoanthraquinone-2-sulfonate (ASA-2) was used as a model anthraquinone compound, the response mechanism of Rhodococcus pyridinivorans GF3 to ASA-2 using genomics and transcriptomics techniques was investigated. Comparative genome analysis showed that strain GF3 owned an especial gene region (Genes 1337-1399) containing the genes encoding cytochrome P450, monooxygenase, dehydrogenase and oxidoreductase, which did not commonly exist in Rhodococcus genus. The amino acid sequences of these genes were similar to those of the cleavage enzymes of anthraquinone ring in Aspergillus genus. Moreover, the transcriptions of Genes 1392-1394 (cytochrome 450 gene cluster) displayed 1.8-3.1-fold up-regulation under ASA-2 exposure. Meanwhile, as an intermediate product of ASA-2, catechol was degraded to acetyl-CoA, succinyl-CoA and pyruvate, resulting in the enhanced tricarboxylic acid cycle and ATP generation. This process also promoted the up-regulation of the genes encoding resistance, efflux, transporter and anti-oxidation pressure proteins, which were involved in resisting ASA-2 and maintaining the homeostasis of cells. These results provided us with a further understanding of the molecular mechanism of degradation and detoxification of ACs.
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Affiliation(s)
- Xiaolei Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Hong Lu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
| | - Qiansheng Li
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Yang Zhou
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China; School of Civil and Environmental Engineering, Harbin Institute of Technology, Shenzhen 518055, China
| | - Jiti Zhou
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
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Cheng M, Chen D, Parales RE, Jiang J. Oxygenases as Powerful Weapons in the Microbial Degradation of Pesticides. Annu Rev Microbiol 2022; 76:325-348. [PMID: 35650666 DOI: 10.1146/annurev-micro-041320-091758] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Oxygenases, which catalyze the reductive activation of O2 and incorporation of oxygen atoms into substrates, are widely distributed in aerobes. They function by switching the redox states of essential cofactors that include flavin, heme iron, Rieske non-heme iron, and Fe(II)/α-ketoglutarate. This review summarizes the catalytic features of flavin-dependent monooxygenases, heme iron-dependent cytochrome P450 monooxygenases, Rieske non-heme iron-dependent oxygenases, Fe(II)/α-ketoglutarate-dependent dioxygenases, and ring-cleavage dioxygenases, which are commonly involved in pesticide degradation. Heteroatom release (hydroxylation-coupled hetero group release), aromatic/heterocyclic ring hydroxylation to form ring-cleavage substrates, and ring cleavage are the main chemical fates of pesticides catalyzed by these oxygenases. The diversity of oxygenases, specificities for electron transport components, and potential applications of oxygenases are also discussed. This article summarizes our current understanding of the catalytic mechanisms of oxygenases and a framework for distinguishing the roles of oxygenases in pesticide degradation. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Minggen Cheng
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs and Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China;
| | - Dian Chen
- State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Rebecca E Parales
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California, USA
| | - Jiandong Jiang
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs and Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China;
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Nicholls HCG, Rolfe SA, Mallinson HEH, Hjort M, Spence MJ, Bonte M, Thornton SF. Distribution of ETBE-degrading microorganisms and functional capability in groundwater, and implications for characterising aquifer ETBE biodegradation potential. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:1223-1238. [PMID: 34350568 PMCID: PMC8724112 DOI: 10.1007/s11356-021-15606-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
Microbes in aquifers are present suspended in groundwater or attached to the aquifer sediment. Groundwater is often sampled at gasoline ether oxygenate (GEO)-impacted sites to assess the potential biodegradation of organic constituents. However, the distribution of GEO-degrading microorganisms between the groundwater and aquifer sediment must be understood to interpret this potential. In this study, the distribution of ethyl tert-butyl ether (ETBE)-degrading organisms and ETBE biodegradation potential was investigated in laboratory microcosm studies and mixed groundwater-aquifer sediment samples obtained from pumped monitoring wells at ETBE-impacted sites. ETBE biodegradation potential (as determined by quantification of the ethB gene) was detected predominantly in the attached microbial communities and was below detection limit in the groundwater communities. The copy number of ethB genes varied with borehole purge volume at the field sites. Members of the Comamonadaceae and Gammaproteobacteria families were identified as responders for ETBE biodegradation. However, the detection of the ethB gene is a more appropriate function-based indicator of ETBE biodegradation potential than taxonomic analysis of the microbial community. The study shows that a mixed groundwater-aquifer sediment (slurry) sample collected from monitoring wells after minimal purging can be used to assess the aquifer ETBE biodegradation potential at ETBE-release sites using this function-based concept.
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Affiliation(s)
- Henry C G Nicholls
- Groundwater Protection and Restoration Group, Department of Civil and Structural Engineering, University of Sheffield, S1 3JD, Sheffield, UK
| | - Stephen A Rolfe
- Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, S10 2TN, Sheffield, UK
| | - Helen E H Mallinson
- Groundwater Protection and Restoration Group, Department of Civil and Structural Engineering, University of Sheffield, S1 3JD, Sheffield, UK
| | - Markus Hjort
- Concawe, Boulevard du Souverain 165, 1160, Brussels, Belgium
| | - Michael J Spence
- Concawe, Boulevard du Souverain 165, 1160, Brussels, Belgium
- British Geological Survey, Environmental Science Centre, Keyworth, Nottingham, NG12 5GG, UK
| | - Matthijs Bonte
- Concawe, Boulevard du Souverain 165, 1160, Brussels, Belgium
- Shell Global Solutions International B.V., Rijswijk, 2288GK, The Netherlands
- Ministry of Infrastructure and Water Management, The Hague, The Netherlands
| | - Steven F Thornton
- Groundwater Protection and Restoration Group, Department of Civil and Structural Engineering, University of Sheffield, S1 3JD, Sheffield, UK.
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Wei G, Shu X, Yao Y, Zhang K, Zhang J, Gao SS. Heterologous Production of Unnatural Flavipucine Family Products Provides Insights into Flavipucines Biosynthesis. Org Lett 2021; 23:7708-7712. [PMID: 34554766 DOI: 10.1021/acs.orglett.1c02566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Heterologous expression of the flavipucine biosynthetic gene cluster in Aspergillus nidulans led to the production of flavipucine (1) and dihydroisoflavipucine (3), as well as six unusual flavipucine related products containing three classes of heterocycles. This combined with gene inactivation, chemical complementation, and transcriptome analysis demonstrated unprecedented ways to form 2-pyridone and 2-pyrone structures by the oxidative rearrangements of pyrrolinone precursors as well as provided insights into the biosynthesis of this important class of natural products.
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Affiliation(s)
- Guangzheng Wei
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China.,University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Xian Shu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China.,University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Yongpeng Yao
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Kexin Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China.,University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Jun Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Shu-Shan Gao
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
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8
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Alonso-Reyes DG, Galván FS, Portero LR, Alvarado NN, Farías ME, Vazquez MP, Albarracín VH. Genomic insights into an andean multiresistant soil actinobacterium of biotechnological interest. World J Microbiol Biotechnol 2021; 37:166. [PMID: 34463818 PMCID: PMC8405860 DOI: 10.1007/s11274-021-03129-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/14/2021] [Indexed: 12/01/2022]
Abstract
Central-Andean Ecosystems (between 2000 and 6000 m above sea level (masl) are typical arid-to-semiarid environments suffering from the highest total solar and ultraviolet-B radiation on the planet but displaying numerous salt flats and shallow lakes. Andean microbial ecosystems isolated from these environments are of exceptional biodiversity enduring multiple severe conditions. Furthermore, the polyextremophilic nature of the microbes in such ecosystems indicates the potential for biotechnological applications. Within this context, the study undertaken used genome mining, physiological and microscopical characterization to reveal the multiresistant profile of Nesterenkonia sp. Act20, an actinobacterium isolated from the soil surrounding Lake Socompa, Salta, Argentina (3570 masl). Ultravioet-B, desiccation, and copper assays revealed the strain's exceptional resistance to all these conditions. Act20's genome presented coding sequences involving resistance to antibiotics, low temperatures, ultraviolet radiation, arsenic, nutrient-limiting conditions, osmotic stress, low atmospheric-oxygen pressure, heavy-metal stress, and toxic fluoride and chlorite. Act20 can also synthesize proteins and natural products such as an insecticide, bacterial cellulose, ectoine, bacterial hemoglobin, and even antibiotics like colicin V and aurachin C. We also found numerous enzymes for animal- and vegetal-biomass degradation and applications in other industrial processes. The resilience of Act20 and its biotechnologic potential were thoroughly demonstrated in this work.
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Affiliation(s)
- Daniel Gonzalo Alonso-Reyes
- Laboratorio de Microbiología Ultraestructural y Molecular, Centro Integral de Microscopía Electrónica (CIME), Facultad de Agronomía y Zootecnia, UNT y CONICET, San Miguel de Tucumán, Tucumán, Argentina
| | - Fátima Silvina Galván
- Laboratorio de Microbiología Ultraestructural y Molecular, Centro Integral de Microscopía Electrónica (CIME), Facultad de Agronomía y Zootecnia, UNT y CONICET, San Miguel de Tucumán, Tucumán, Argentina
| | - Luciano Raúl Portero
- Laboratorio de Microbiología Ultraestructural y Molecular, Centro Integral de Microscopía Electrónica (CIME), Facultad de Agronomía y Zootecnia, UNT y CONICET, San Miguel de Tucumán, Tucumán, Argentina
| | - Natalia Noelia Alvarado
- Laboratorio de Microbiología Ultraestructural y Molecular, Centro Integral de Microscopía Electrónica (CIME), Facultad de Agronomía y Zootecnia, UNT y CONICET, San Miguel de Tucumán, Tucumán, Argentina
| | - María Eugenia Farías
- Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas (LIMLA), Planta Piloto de Procesos Industriales y Microbiológicos (PROIMI), CCT, CONICET, San Miguel de Tucumán, Tucumán, Argentina
| | - Martín P Vazquez
- HERITAS-CONICET, Ocampo 210 bis, Predio CCT, 2000, Rosario, Santa Fe, Argentina
| | - Virginia Helena Albarracín
- Laboratorio de Microbiología Ultraestructural y Molecular, Centro Integral de Microscopía Electrónica (CIME), Facultad de Agronomía y Zootecnia, UNT y CONICET, San Miguel de Tucumán, Tucumán, Argentina.
- Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, San Miguel de Tucumán, Tucumán, Argentina.
- Centro Integral de Microscopía Electrónica (CIME, CONICET, UNT), Camino de Sirga s/n. FAZ, Finca El Manantial, 4107, Yerba Buena, Tucumán, Argentina.
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Liu HM, Yuan M, Liu AM, Ren L, Zhu GP, Sun LN. A bifunctional enzyme belonging to cytochrome P450 family involved in the O-dealkylation and N-dealkoxymethylation toward chloroacetanilide herbicides in Rhodococcus sp. B2. Microb Cell Fact 2021; 20:61. [PMID: 33663497 PMCID: PMC7934444 DOI: 10.1186/s12934-021-01544-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 02/18/2021] [Indexed: 11/22/2022] Open
Abstract
Background The chloroacetamide herbicides pretilachlor is an emerging pollutant. Due to the large amount of use, its presence in the environment threatens human health. However, the molecular mechanism of pretilachlor degradation remains unknown. Results Now, Rhodococcus sp. B2 was isolated from rice field and shown to degrade pretilachlor. The maximum pretilachlor degradation efficiency (86.1%) was observed at a culture time of 5 d, an initial substrate concentration 50 mg/L, pH 6.98, and 30.1 °C. One novel metabolite N-hydroxyethyl-2-chloro-N-(2, 6-diethyl-phenyl)-acetamide was identified by gas chromatography-mass spectrometry (GC–MS). Draft genome comparison demonstrated that a 32,147-bp DNA fragment, harboring gene cluster (EthRABCDB2), was absent from the mutant strain TB2 which could not degrade pretilachlor. The Eth gene cluster, encodes an AraC/XylS family transcriptional regulator (EthRB2), a ferredoxin reductase (EthAB2), a cytochrome P450 monooxygenase (EthBB2), a ferredoxin (EthCB2) and a 10-kDa protein of unknown function (EthDB2). Complementation with EthABCDB2 and EthABDB2, but not EthABCB2 in strain TB2 restored its ability to degrade chloroacetamide herbicides. Subsequently, codon optimization of EthABCDB2 was performed, after which the optimized components were separately expressed in Escherichia coli, and purified using Ni-affinity chromatography. A mixture of EthABCDB2 or EthABDB2 but not EthABCB2 catalyzed the N-dealkoxymethylation of alachlor, acetochlor, butachlor, and propisochlor and O-dealkylation of pretilachlor, revealing that EthDB2 acted as a ferredoxin in strain B2. EthABDB2 displayed maximal activity at 30 °C and pH 7.5. Conclusions This is the first report of a P450 family oxygenase catalyzing the O-dealkylation and N-dealkoxymethylation of pretilachlor and propisochlor, respectively. And the results of the present study provide a microbial resource for the remediation of chloroacetamide herbicides-contaminated sites.![]()
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Affiliation(s)
- Hong-Ming Liu
- The Research Center of Life Omics and Health, Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, Anhui Normal University, Wuhu, 241000, Anhui, People's Republic of China
| | - Meng Yuan
- The Research Center of Life Omics and Health, Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, Anhui Normal University, Wuhu, 241000, Anhui, People's Republic of China
| | - Ai-Min Liu
- The Research Center of Life Omics and Health, Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, Anhui Normal University, Wuhu, 241000, Anhui, People's Republic of China
| | - Lei Ren
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Guo-Ping Zhu
- The Research Center of Life Omics and Health, Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, Anhui Normal University, Wuhu, 241000, Anhui, People's Republic of China.
| | - Li-Na Sun
- Eco-Environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, People's Republic of China.
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Thornton SF, Nicholls HCG, Rolfe SA, Mallinson HEH, Spence MJ. Biodegradation and fate of ethyl tert-butyl ether (ETBE) in soil and groundwater: A review. JOURNAL OF HAZARDOUS MATERIALS 2020; 391:122046. [PMID: 32145642 DOI: 10.1016/j.jhazmat.2020.122046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 12/07/2019] [Accepted: 01/07/2020] [Indexed: 06/10/2023]
Abstract
This review summarises the current state of knowledge on the biodegradation and fate of the gasoline ether oxygenate ethyl tert-butyl ether (ETBE) in soil and groundwater. Microorganisms have been identified in soil and groundwater with the ability to degrade ETBE aerobically as a carbon and energy source, or via cometabolism using alkanes as growth substrates. Aerobic biodegradation of ETBE initially occurs via hydroxylation of the ethoxy carbon by a monooxygenase enzyme, with subsequent formation of intermediates which include acetaldehyde, tert-butyl acetate (TBAc), tert-butyl alcohol (TBA), 2-hydroxy-2-methyl-1-propanol (MHP) and 2-hydroxyisobutyric acid (2-HIBA). Slow cell growth and low biomass yields on ETBE are believed to result from the ether structure and slow degradation kinetics, with potential limitations on ETBE metabolism. Genes known to facilitate transformation of ETBE include ethB (within the ethRABCD cluster), encoding a cytochrome P450 monooxygenase, and alkB-encoding alkane hydroxylases. Other genes have been identified in microorganisms but their activity and specificity towards ETBE remains poorly characterised. Microorganisms and pathways supporting anaerobic biodegradation of ETBE have not been identified, although this potential has been demonstrated in limited field and laboratory studies. The presence of co-contaminants (other ether oxygenates, hydrocarbons and organic compounds) in soil and groundwater may limit aerobic biodegradation of ETBE by preferential metabolism and consumption of available dissolved oxygen or enhance ETBE biodegradation through cometabolism. Both ETBE-degrading microorganisms and alkane-oxidising bacteria have been characterised, with potential for use in bioaugmentation and biostimulation of ETBE degradation in groundwater.
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Affiliation(s)
- S F Thornton
- Groundwater Protection and Restoration Group, Dept of Civil and Structural Engineering, University of Sheffield, Sheffield S1 3JD, UK
| | - H C G Nicholls
- Groundwater Protection and Restoration Group, Dept of Civil and Structural Engineering, University of Sheffield, Sheffield S1 3JD, UK
| | - S A Rolfe
- Dept of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Sheffield S10 2TN, UK
| | - H E H Mallinson
- Groundwater Protection and Restoration Group, Dept of Civil and Structural Engineering, University of Sheffield, Sheffield S1 3JD, UK
| | - M J Spence
- Concawe, Environmental Science for European Refining, Boulevard du Souverain 165, 1160 Brussels, Belgium
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Nicholls HCG, Mallinson HEH, Rolfe SA, Hjort M, Spence MJ, Thornton SF. Influence of contaminant exposure on the development of aerobic ETBE biodegradation potential in microbial communities from a gasoline-impacted aquifer. JOURNAL OF HAZARDOUS MATERIALS 2020; 388:122022. [PMID: 31962211 DOI: 10.1016/j.jhazmat.2020.122022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 12/14/2019] [Accepted: 01/02/2020] [Indexed: 06/10/2023]
Abstract
Aerobic biodegradation of ethyl tert butyl ether (ETBE) in a gasoline-impacted aquifer was investigated in laboratory microcosms containing groundwater and aquifer material from ETBE-impacted and non-impacted locations amended with either ETBE, or ETBE plus methyl tert butyl ether (MTBE). As sole substrate, ETBE was biodegraded (maximum rate of 0.54 day-1) without a lag in ETBE-impacted microcosms but with a lag of up to 66 days in non-impacted microcosms (maximum rate of 0.38 day-1). As co-substrate, ETBE was biodegraded preferentially (maximum rate of 0.25 and 0.99 day-1 in non-impacted and impacted microcosms, respectively) before MTBE (maximum rate of 0.24 and 0.36 day-1 in non-impacted and impacted microcosms, respectively). Further addition of ETBE and MTBE reduced lags and increased biodegradation rates. ethB gene copy numbers increased significantly (>100 fold) after exposure to ETBE, while overall cell numbers remained constant, suggesting that ethB-containing microorganisms come to dominate the microbial communities. Deep sequencing of 16S rRNA genes identified members of the Comamonadaceae family that increased in relative abundance upon exposure to ETBE. This study demonstrates the potential for ETBE biodegradation within the unsaturated and saturated zone, and that ETBE biodegrading capability is rapidly developed and maintained within the aquifer microbial community over extended timescales.
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Affiliation(s)
- H C G Nicholls
- Groundwater Protection and Restoration Group, Dept of Civil and Structural Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom
| | - H E H Mallinson
- Groundwater Protection and Restoration Group, Dept of Civil and Structural Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom
| | - S A Rolfe
- Dept of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - M Hjort
- Concawe, Environmental Science for European Refining, Boulevard du Souverain 165, 1160 Brussels, Belgium
| | - M J Spence
- Concawe, Environmental Science for European Refining, Boulevard du Souverain 165, 1160 Brussels, Belgium
| | - S F Thornton
- Groundwater Protection and Restoration Group, Dept of Civil and Structural Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom.
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12
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Kan J, Peng T, Huang T, Xiong G, Hu Z. NarL, a Novel Repressor for CYP108j1 Expression during PAHs Degradation in Rhodococcus sp. P14. Int J Mol Sci 2020; 21:ijms21030983. [PMID: 32024188 PMCID: PMC7037279 DOI: 10.3390/ijms21030983] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/27/2020] [Accepted: 01/30/2020] [Indexed: 12/18/2022] Open
Abstract
Rhodococcus sp. P14 was isolated from crude-oil-contaminated sediments, and a wide range of polycyclic aromatic hydrocarbons (PAHs) could be used as the sole source of carbon and energy. A key CYP450 gene, designated as cyp108j1 and involved in the degradation of PAHs, was identified and was able to hydroxylate various PAHs. However, the regulatory mechanism of the expression of cyp108j1 remains unknown. In this study, we found that the expression of cyp108j1 is negatively regulated by a LuxR (helix-turn-helix transcription factors in acyl-homoserine lactones-mediated quorum sensing) family regulator, NarL (nitrate-dependent two-component regulatory factor), which is located upstream of cyp108j1. Further analysis revealed that NarL can directly bind to the promoter region of cyp108j1. Mutational experiments demonstrated that the binding site between NarL and the cyp108j1 promoter was the palindromic sequence GAAAGTTG-CAACTTTC. Together, the finding reveal that NarL is a novel repressor for the expression of cyp108j1 during PAHs degradation.
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Affiliation(s)
- Jie Kan
- Department of Biology, Shantou University, Shantou 515063, China; (J.K.); (T.P.); (T.H.)
| | - Tao Peng
- Department of Biology, Shantou University, Shantou 515063, China; (J.K.); (T.P.); (T.H.)
| | - Tongwang Huang
- Department of Biology, Shantou University, Shantou 515063, China; (J.K.); (T.P.); (T.H.)
| | - Guangming Xiong
- Institute of Toxicology and Pharmacology for Natural Scientists, University Medical School Schleswig-Holstein, 24103 Kiel, Germany;
| | - Zhong Hu
- Department of Biology, Shantou University, Shantou 515063, China; (J.K.); (T.P.); (T.H.)
- Correspondence:
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13
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Distinct Bacterial Consortia Established in ETBE-Degrading Enrichments from a Polluted Aquifer. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9204247] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ethyl tert-butyl ether (ETBE) is a gasoline additive that became an important aquifer pollutant. The information about natural bacterial consortia with a capacity for complete ETBE degradation is limited. Here we assess the taxonomical composition of bacterial communities and diversity of the ethB gene (involved in ETBE biodegradation) in ETBE-enrichment cultures that were established from a gasoline-polluted aquifer, either from anoxic ETBE-polluted plume water (PW), or from an upstream non-polluted water (UW). We used a 16S rRNA microarray, and 16S rRNA and ethB gene sequencing. Despite the dissimilar initial chemical conditions and microbial composition, ETBE-degrading consortia were obtained from both PW and UW. The composition of ETBE-enrichment cultures was distinct from their initial water samples, reflecting the importance of the rare biosphere as a reservoir of potential ETBE degraders. No convergence was observed between the enrichment cultures originating from UW and PW, which were dominated by Mesorhizobium and Hydrogenophaga, respectively, indicating that distinct consortia with the same functional properties may be present at one site. Conserved ethB genes were evidenced in both PW and UW ETBE-enrichment cultures and in PW water. Our results suggest that the presence of ethB genes rather than the taxonomical composition of in situ bacterial communities indicate the potential for the ETBE degradation at a given site.
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14
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Draft Genome Sequence of Mycolicibacterium sp. Strain CH28, a Potential Degrader of Diisopropyl Ether, Isolated from Pharmaceutical Wastewater. Microbiol Resour Announc 2019; 8:8/37/e00682-19. [PMID: 31515342 PMCID: PMC6742793 DOI: 10.1128/mra.00682-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycolicibacterium sp. strain CH28 is a novel bacterial isolate belonging to a group of rapidly growing mycobacteria. Here, we report the draft genome sequence of strain CH28 and provide insights into the genetic background of its potential diisopropyl ether-degrading capability.
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15
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Microbial Community Analysis Provides Insights into the Effects of Tetrahydrofuran on 1,4-Dioxane Biodegradation. Appl Environ Microbiol 2019; 85:AEM.00244-19. [PMID: 30926731 DOI: 10.1128/aem.00244-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 03/20/2019] [Indexed: 11/20/2022] Open
Abstract
Tetrahydrofuran (THF) is known to induce the biodegradation of 1,4-dioxane (dioxane), an emerging contaminant, but the mechanisms by which THF affects dioxane biodegradation in microbial communities are not well understood. To fill this knowledge gap, changes in the microbial community structure in microcosm experiments with synthetic medium and landfill leachate were examined over time using 16S rRNA gene amplicon sequencing and functional gene quantitative PCR assays. The overarching hypothesis being tested was that THF promoted dioxane biodegradation by increasing the abundance of dioxane-degrading bacteria in the consortium. The data revealed that in experiments with synthetic medium, the addition of THF significantly increased the abundance of Pseudonocardia, a genus with several representatives that can grow on both dioxane and THF, and of Rhodococ cus ruber, a species that can use THF as the primary growth substrate while cometabolizing dioxane. However, in similar experiments with landfill leachate, only R. ruber was significantly enriched. When the THF concentration was higher than the dioxane concentration, THF competitively inhibited dioxane degradation since dioxane degradation was negligible, while the dioxane-degrading bacteria and the corresponding THF/dioxane monooxygenase gene copies increased by a few orders of magnitude.IMPORTANCE Widespread in groundwater and carcinogenic to humans, 1,4-dioxane (dioxane) is attracting significant attention in recent years. Advanced oxidation processes can effectively remove dioxane but require high energy consumption and operation costs. Biological removal of dioxane is of particular interest due to the ability of some bacteria to mineralize dioxane at a low energy cost. Although dioxane is generally considered recalcitrant to biodegradation, more than 20 types of bacteria can degrade dioxane as the sole electron donor substrate or the secondary electron donor substrate. In the latter case, tetrahydrofuran (THF) is commonly studied as the primary electron donor substrate. Previous work has shown that THF promotes dioxane degradation at a low THF concentration but inhibits dioxane degradation at a high THF concentration. Our work expanded on the previous work by mechanically examining the effects of THF on dioxane degradation in a microbial community context.
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16
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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.![]()
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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
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17
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Purswani J, Guisado IM, Coello-Cabezas J, González-López J, Pozo C. Social microbial inocula confer functional stability in a methyl tert-butyl ether extractive membrane biofilm bioreactor. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 244:855-860. [PMID: 30390459 DOI: 10.1016/j.envpol.2018.10.100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/19/2018] [Accepted: 10/24/2018] [Indexed: 06/08/2023]
Abstract
Methyl tert-butyl ether (MTBE) degradation technologies based on two-phase partitioning systems such as extractive membrane biofilm reactors (EMBFR) permit separation of biological and contaminant compartments, thus allowing optimization of the biological section. In this study, we set-up an EMBFR with three MTBE-degrading and cooperating strains (termed social biofilm: Agrobacterium sp. MS2, Paenibacillus etheri SH7T and Rhodococcus ruber EE6). The removal efficiency of the social-biofilm EMBFR was 80%, and functional stability was observed in the reactor, i.e. more efficient than previous studies (single-strain inoculated EMBFR, <50% removal efficiency and unstable function). Metabolite tert-butyl alcohol was not observed, and the EC50 values were higher than those observed in single-strain EMBFRs. Comparative analysis of the MTBE enzymatic pathway and the social-biofilm was performed, where the mechanism of cooperation observed within the social-biofilm is likely due to enzymatic redundancy. Functional outcomes were equal to previous batch tests, hence 100% scalability was obtained. Overall, higher functional and stability outcomes are obtained with the use of the social-biofilm in an MTBE-EMBFR.
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Affiliation(s)
- Jessica Purswani
- Environmental Microbiology Group, Institute of Water Research, University of Granada, Granada, Spain; Department of Microbiology, University of Granada, Granada, Spain.
| | - Isabel M Guisado
- Environmental Microbiology Group, Institute of Water Research, University of Granada, Granada, Spain; Department of Microbiology, University of Granada, Granada, Spain
| | - Julio Coello-Cabezas
- Environmental Microbiology Group, Institute of Water Research, University of Granada, Granada, Spain
| | - Jesús González-López
- Environmental Microbiology Group, Institute of Water Research, University of Granada, Granada, Spain; Department of Microbiology, University of Granada, Granada, Spain
| | - Clementina Pozo
- Environmental Microbiology Group, Institute of Water Research, University of Granada, Granada, Spain; Department of Microbiology, University of Granada, Granada, Spain
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18
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van der Waals MJ, Plugge C, Meima-Franke M, de Waard P, Bodelier PLE, Smidt H, Gerritse J. Ethyl tert-butyl ether (EtBE) degradation by an algal-bacterial culture obtained from contaminated groundwater. WATER RESEARCH 2019; 148:314-323. [PMID: 30391860 DOI: 10.1016/j.watres.2018.10.050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 10/16/2018] [Accepted: 10/17/2018] [Indexed: 06/08/2023]
Abstract
EtBE is a fuel oxygenate that is synthesized from (bio)ethanol and fossil-based isobutylene, and replaces the fossil-based MtBE. Biodegradation of EtBE to harmless metabolites or end products can reduce the environmental and human health risks after accidental release. In this study, an algal-bacterial culture enriched from contaminated groundwater was used to (i) assess the potential for EtBE degradation, (ii) resolve the EtBE degradation pathway and (iii) characterize the phylogenetic composition of the bacterial community involved in EtBE degradation in contaminated groundwater. In an unamended microcosm, algal growth was observed after eight weeks when exposed to a day-night light cycle. In the fed-batch reactor, oxygen produced by the algae Scenedesmus and Chlorella was used by bacteria to degrade 50 μM EtBE replenishments with a cumulative total of 1250 μM in a day/night cycle (650 lux), over a period of 913 days. The microbial community in the fed-batch reactor degraded EtBE, using a P450 monooxygenase and 2-hydroxyisobutyryl-CoA mutase, to tert-butyl alcohol (TBA), ethanol and CO2 as determined using 13C nuclear magnetic resonance spectroscopy (NMR) and gas chromatography. Stable isotope probing (SIP) with 13C6 labeled EtBE in a fed-batch vessel showed no significant difference in community profiles of the 13C and 12C enriched DNA fractions, with representatives of the families Halomonadaceae, Shewanellaceae, Rhodocyclaceae, Oxalobacteraceae, Comamonadaceae, Sphingomonadaceae, Hyphomicrobiaceae, Candidatus Moranbacteria, Omnitrophica, Anaerolineaceae, Nocardiaceae, and Blastocatellaceae. This is the first study describing micro-oxic degradation of EtBE by an algal-bacterial culture. This algal-bacterial culture has advantages compared with conventional aerobic treatments: (i) a lower risk of EtBE evaporation and (ii) no need for external oxygen supply in the presence of light. This study provides novel leads towards future possibilities to implement algal-bacterial consortia in field-scale groundwater or wastewater treatment.
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Affiliation(s)
- Marcelle J van der Waals
- Deltares, Subsurface and Groundwater Systems, Daltonlaan 600, 3584 BK, Utrecht, the Netherlands; Wageningen University & Research, Laboratory of Microbiology, Stippeneng 4, 6708 WE, Wageningen, the Netherlands.
| | - Caroline Plugge
- Wageningen University & Research, Laboratory of Microbiology, Stippeneng 4, 6708 WE, Wageningen, the Netherlands
| | - Marion Meima-Franke
- The Netherlands Institute of Ecology (NIOO-KNAW), Department of Microbial Ecology, Droevendaalsesteeg 10, 6708 PB, Wageningen, the Netherlands
| | - Pieter de Waard
- Wageningen University & Research, BioNanoTechnology, Bornse Weilanden 9, 6700 EK, Wageningen, the Netherlands
| | - Paul L E Bodelier
- The Netherlands Institute of Ecology (NIOO-KNAW), Department of Microbial Ecology, Droevendaalsesteeg 10, 6708 PB, Wageningen, the Netherlands
| | - Hauke Smidt
- Wageningen University & Research, Laboratory of Microbiology, Stippeneng 4, 6708 WE, Wageningen, the Netherlands
| | - Jan Gerritse
- Deltares, Subsurface and Groundwater Systems, Daltonlaan 600, 3584 BK, Utrecht, the Netherlands
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19
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Purswani J, Romero-Zaliz RC, Martín-Platero AM, Guisado IM, González-López J, Pozo C. BSocial: Deciphering Social Behaviors within Mixed Microbial Populations. Front Microbiol 2017; 8:919. [PMID: 28596759 PMCID: PMC5442188 DOI: 10.3389/fmicb.2017.00919] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Accepted: 05/08/2017] [Indexed: 12/01/2022] Open
Abstract
Ecosystem functionality depends on interactions among populations, of the same or different taxa, and these are not just the sum of pairwise interactions. Thus, know-how of the social interactions occurring in mixed-populations are of high interest, however they are commonly unknown due to the limitations posed in tagging each population. The limitations include costs/time in tediously fluorescent tagging, and the number of different fluorescent tags. Tag-free strategies exist, such as high-throughput sequencing, but ultimately both strategies require the use of expensive machinery. Our work appoints social behaviors on individual strains in mixed-populations, offering a web-tool (BSocialhttp://m4m.ugr.es/BSocial.html) for analyzing the community framework. Our quick and cheap approach includes the periodic monitoring of optical density (OD) from a full combinatorial testing of individual strains, where number of generations and growth rate are determined. The BSocial analyses then enable us to determine how the addition/absence of a particular species affects the net productivity of a microbial community and use this to select productive combinations, i.e., designate their social effect on a general community. Positive, neutral, or negative assignations are applied to describe the social behavior within the community by comparing fitness effects of the community against the individual strain. The usefulness of this tool for selection of optimal inoculum in biofilm-based methyl tert-butyl ether (MTBE) bioremediation was demonstrated. The studied model uses seven bacterial strains with diverse MTBE degradation/growth capacities. Full combinatorial testing of seven individual strains (triplicate tests of 127 combinations) were implemented, along with MTBE degradation as the desired function. Sole observation of highest species fitness did not render the best functional outcome, and only when strains with positive and neutral social assignations were mixed (Rhodococcus ruber EE6, Agrobacterium sp. MS2 and Paenibacillus etheri SH7), was this obtained. Furthermore, the use of positive and neutral strains in all its combinations had a significant higher degradation mean (x1.75) than exclusive negative strain combinations. Thus, social microbial processes benefit bioremediation more than negative social microbial combinations. The BSocial webtool is a great contributor to the study of social interactions in bioremediation processes, and may be used in other natural or synthetic habitat studies.
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Affiliation(s)
- Jessica Purswani
- Environmental Microbiology Group, Institute of Water Research, University of GranadaGranada, Spain.,Department of Microbiology, University of GranadaGranada, Spain
| | - Rocío C Romero-Zaliz
- M4Mlab, Department of Computer Science and Artificial Intelligence, University of GranadaGranada, Spain
| | | | - Isabel M Guisado
- Environmental Microbiology Group, Institute of Water Research, University of GranadaGranada, Spain.,Department of Microbiology, University of GranadaGranada, Spain
| | - Jesús González-López
- Environmental Microbiology Group, Institute of Water Research, University of GranadaGranada, Spain.,Department of Microbiology, University of GranadaGranada, Spain
| | - Clementina Pozo
- Environmental Microbiology Group, Institute of Water Research, University of GranadaGranada, Spain.,Department of Microbiology, University of GranadaGranada, Spain
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20
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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.
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21
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Acharya G, Kaur G, Subramanian S. Evolutionary relationships between heme-binding ferredoxin α + β barrels. BMC Bioinformatics 2016; 17:168. [PMID: 27089923 PMCID: PMC4835899 DOI: 10.1186/s12859-016-1033-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 04/12/2016] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The α + β barrel superfamily of the ferredoxin-like fold consists of a functionally diverse group of evolutionarily related proteins. The barrel architecture of these proteins is formed by either homo-/hetero-dimerization or duplication and fusion of ferredoxin-like domains. Several members of this superfamily bind heme in order to carry out their functions. RESULTS We analyze the heme-binding sites in these proteins as well as their barrel topologies. Our comparative structural analysis of these heme-binding barrels reveals two distinct modes of packing of the ferredoxin-like domains to constitute the α + β barrel, which is typified by the Type-1/IsdG-like and Type-2/OxdA-like proteins, respectively. We examine the heme-binding pockets and explore the versatility of the α + β barrels ability to accommodate heme or heme-related moieties, such as siroheme, in at least three different sites, namely, the mode seen in IsdG/OxdA, Cld/DyP/EfeB/HemQ and siroheme decarboxylase barrels. CONCLUSIONS Our study offers insights into the plausible evolutionary relationships between the two distinct barrel packing topologies and relate the observed heme-binding sites to these topologies.
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Affiliation(s)
- Giriraj Acharya
- CSIR-Institute of Microbial Technology (IMTECH), Sector 39-A, Chandigarh, India
| | - Gurmeet Kaur
- CSIR-Institute of Microbial Technology (IMTECH), Sector 39-A, Chandigarh, India
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22
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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.
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Affiliation(s)
- Shanshan Li
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China
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23
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Involvement of the cytochrome P450 system EthBAD in the N-deethoxymethylation of acetochlor by Rhodococcus sp. strain T3-1. Appl Environ Microbiol 2015; 81:2182-8. [PMID: 25595756 DOI: 10.1128/aem.03764-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)-acetamide] is a widely applied herbicide with potential carcinogenic properties. N-Deethoxymethylation is the key step in acetochlor biodegradation. N-Deethoxymethylase is a multicomponent enzyme that catalyzes the conversion of acetochlor to 2'-methyl-6'-ethyl-2-chloroacetanilide (CMEPA). Fast detection of CMEPA by a two-enzyme (N-deethoxymethylase-amide hydrolase) system was established in this research. Based on the fast detection method, a three-component enzyme was purified from Rhodococcus sp. strain T3-1 using ammonium sulfate precipitation and hydrophobic interaction chromatography. The molecular masses of the components of the purified enzyme were estimated to be 45, 43, and 11 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Based on the results of peptide mass fingerprint analysis, acetochlor N-deethoxymethylase was identified as a cytochrome P450 system, composed of a cytochrome P450 oxygenase (43-kDa component; EthB), a ferredoxin (45 kDa; EthA), and a reductase (11 kDa; EthD), that is involved in the degradation of methyl tert-butyl ether. The gene cluster ethABCD was cloned by PCR amplification and expressed in Escherichia coli BL21(DE3). Resting cells of a recombinant E. coli strain showed deethoxymethylation activity against acetochlor. Subcloning of ethABCD showed that ethABD expressed in E. coli BL21(DE3) has the activity of acetochlor N-deethoxymethylase and is capable of converting acetochlor to CMEPA.
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Auffret MD, Yergeau E, Labbé D, Fayolle-Guichard F, Greer CW. Importance of Rhodococcus strains in a bacterial consortium degrading a mixture of hydrocarbons, gasoline, and diesel oil additives revealed by metatranscriptomic analysis. Appl Microbiol Biotechnol 2014; 99:2419-30. [PMID: 25343979 DOI: 10.1007/s00253-014-6159-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 10/12/2014] [Indexed: 11/29/2022]
Abstract
A bacterial consortium (Mix3) composed of microorganisms originating from different environments (soils and wastewater) was obtained after enrichment in the presence of a mixture of 16 hydrocarbons, gasoline, and diesel oil additives. After addition of the mixture, the development of the microbial composition of Mix3 was monitored at three different times (35, 113, and 222 days) using fingerprinting method and dominant bacterial species were identified. In parallel, 14 bacteria were isolated after 113 days and identified. Degradation capacities for Mix3 and the isolated bacterial strains were characterized and compared. At day 113, we induced the expression of catabolic genes in Mix3 by adding the substrate mixture to resting cells and the metatranscriptome was analyzed. After addition of the substrate mixture, the relative abundance of Actinobacteria increased at day 222 while a shift between Rhodococcus and Mycobacterium was observed after 113 days. Mix3 was able to degrade 13 compounds completely, with partial degradation of isooctane and 2-ethylhexyl nitrate, but tert-butyl alcohol was not degraded. Rhodococcus wratislaviensis strain IFP 2016 isolated from Mix3 showed almost the same degradation capacities as Mix3: these results were not observed with the other isolated strains. Transcriptomic results revealed that Actinobacteria and in particular, Rhodococcus species, were major contributors in terms of total and catabolic gene transcripts while other species were involved in cyclohexane degradation. Not all the microorganisms identified at day 113 were active except R. wratislaviensis IFP 2016 that appeared to be a major player in the degradation activity observed in Mix3.
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Affiliation(s)
- Marc D Auffret
- Institut Français du Pétrole (IFP), 1-4 Avenue de Bois-Préau, 92852, Rueil-Malmaison, France,
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Le Digabel Y, Demanèche S, Benoit Y, Fayolle-Guichard F, Vogel TM. Ethyl tert-butyl ether (ETBE)-degrading microbial communities in enrichments from polluted environments. JOURNAL OF HAZARDOUS MATERIALS 2014; 279:502-510. [PMID: 25108826 DOI: 10.1016/j.jhazmat.2014.07.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 06/06/2014] [Accepted: 07/03/2014] [Indexed: 06/03/2023]
Abstract
The ethyl tert-butyl ether (ETBE) degradation capacity and phylogenetic composition of five aerobic enrichment cultures with ETBE as the sole carbon and energy source were studied. In all cases, ETBE was entirely degraded to biomass and CO2. Clone libraries of the 16S rRNA gene were prepared from each enrichment. The analyses of the DNA sequences obtained showed different taxonomic compositions with a majority of Proteobacteria in three cases. The two other enrichments have different microbiota with an abundance of Acidobacteria in one case, whereas the microbiota in the second was more diverse (majority of Actinobacteria, Chlorobi and Gemmatimonadetes). Actinobacteria were detected in all five enrichments. Several bacterial strains were isolated from the enrichments and five were capable of degrading ETBE and/or tert-butyl alcohol (TBA), a degradation intermediate. The five included three Rhodococcus sp. (IFP 2040, IFP 2041, IFP 2043), one Betaproteobacteria (IFP 2047) belonging to the Rubrivivax/Leptothrix/Ideonella branch, and one Pseudonocardia sp. (IFP 2050). Quantification of these five strains and two other strains, Rhodococcus sp. IFP 2042 and Bradyrhizobium sp. IFP2049, which had been previously isolated from one of the enrichments was carried out on the different enrichments based on quantitative PCR with specific 16S rRNA gene primers and the results were consistent with the hypothesized role of Actinobacteria and Betaproteobacteria in the degradation of ETBE and the possible role of Bradyrhizobium strains in the degradation of TBA.
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Affiliation(s)
- Yoann Le Digabel
- Environmental Microbial Genomics, CNRS UMR 5005, Laboratoire Ampère, École Centrale de Lyon, Université de Lyon, 36 avenue Guy de Collongue, 69134 Ecully, France; Institut Français du Pétrole Energies Nouvelles (IFPEN), Biotechnology Departement, 1-4 avenue de Bois-Préau, 92852 Rueil-Malmaison, France
| | - Sandrine Demanèche
- Environmental Microbial Genomics, CNRS UMR 5005, Laboratoire Ampère, École Centrale de Lyon, Université de Lyon, 36 avenue Guy de Collongue, 69134 Ecully, France
| | - Yves Benoit
- Institut Français du Pétrole Energies Nouvelles (IFPEN), Biotechnology Departement, 1-4 avenue de Bois-Préau, 92852 Rueil-Malmaison, France
| | - Françoise Fayolle-Guichard
- Institut Français du Pétrole Energies Nouvelles (IFPEN), Biotechnology Departement, 1-4 avenue de Bois-Préau, 92852 Rueil-Malmaison, France.
| | - Timothy M Vogel
- Environmental Microbial Genomics, CNRS UMR 5005, Laboratoire Ampère, École Centrale de Lyon, Université de Lyon, 36 avenue Guy de Collongue, 69134 Ecully, France
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Biodegradation of fuel oxygenates and their effect on the expression of a newly identified cytochrome P450 gene in Achromobacter xylosoxidans MCM2/2/1. Process Biochem 2014. [DOI: 10.1016/j.procbio.2013.09.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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González-Fernández R, Aloria K, Valero-Galván J, Redondo I, Arizmendi JM, Jorrín-Novo JV. Proteomic analysis of mycelium and secretome of different Botrytis cinerea wild-type strains. J Proteomics 2013; 97:195-221. [PMID: 23811051 DOI: 10.1016/j.jprot.2013.06.022] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 06/10/2013] [Accepted: 06/13/2013] [Indexed: 01/14/2023]
Abstract
UNLABELLED The necrotrophic fungus Botrytis cinerea is a very damaging phytopathogen of wide host range and environmental persistence. It is difficult to control because of its genetic versatility, expressed in the many phenotypical differences among isolates. The genomes of the B. cinerea B05.10 and T4 strains have been recently sequenced, becoming a model system for necrotrophic pathogens, and thus opening new alternatives for functional genomics analysis. In this work, the mycelium and secreted proteome of six wild-type strains with different host range, and grown in liquid minimal medium, have been analyzed by using complementary gel-based (1-DE and 2-DE) and gel-free/label-free (nUPLC-MS(E)) approaches. We found differences in the protein profiles among strains belonging to both the mycelium and the secretome. A total of 47 and 51 variable proteins were identified in the mycelium and the secretome, respectively. Some of them, such as malate dehydrogenase or peptidyl-prolyl cis-trans isomerase from the mycelium, and endopolygalacturonase, aspartic protease or cerato-platanin protein from the secretome have been reported as virulence factors, which are involved in host-tissue invasion, pathogenicity or fungal development. BIOLOGICAL SIGNIFICANCE The necrotrophic fungus Botrytis cinerea is an important phytopathogen of wide host range and environmental persistence, causing substantial economic losses worldwide. In this work, the mycelium and secreted proteome of six B. cinerea wild-type strains with different host range have been analyzed by using complementary gel-based and gel-free/label-free approaches. Fungal genetic versatility was confirmed at the proteome level for both mycelium proteome and secreted proteins. A high number of hypothetical proteins with conserved domains related to toxin compounds or to unknown functions were identified, having qualitative differences among strains. The identification of hypothetical proteins suggests that the B. cinerea strains differ mostly in processes involved in adaptation to a particular environment or a growth condition, rather than in essential metabolic reactions. Proteomics can help in the identification of variable proteins related to the infection and colonization of host plant tissues, as well as of virulence and aggressiveness factors among different B. cinerea wild-type strains. This article is part of a Special Issue entitled: Trends in Microbial Proteomics.
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Affiliation(s)
- Raquel González-Fernández
- Agroforestry and Plant Biochemistry and Proteomics Research Group, Dpt. of Biochemistry and Molecular Biology, University of Cordoba, Agrifood Campus of International Excellence (ceiA3), 14071 Córdoba, Spain.
| | - Kerman Aloria
- Proteomics Core Facility-SGIKER, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain
| | - José Valero-Galván
- Agroforestry and Plant Biochemistry and Proteomics Research Group, Dpt. of Biochemistry and Molecular Biology, University of Cordoba, Agrifood Campus of International Excellence (ceiA3), 14071 Córdoba, Spain; Dpt. of Chemistry-Biology, Biomedical Sciences Institute, Autonomous University of Ciudad Juárez, 32300 Ciudad Juárez, Chihuahua, Mexico. http://www.uco.es/botrytis/
| | - Inmaculada Redondo
- Agroforestry and Plant Biochemistry and Proteomics Research Group, Dpt. of Biochemistry and Molecular Biology, University of Cordoba, Agrifood Campus of International Excellence (ceiA3), 14071 Córdoba, Spain. http://www.uco.es/botrytis/
| | - Jesús M Arizmendi
- Dpt. of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain
| | - Jesús V Jorrín-Novo
- Agroforestry and Plant Biochemistry and Proteomics Research Group, Dpt. of Biochemistry and Molecular Biology, University of Cordoba, Agrifood Campus of International Excellence (ceiA3), 14071 Córdoba, Spain. http://www.uco.es/botrytis/
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Ethyl tert-butyl ether (ETBE) biodegradation by a syntrophic association of Rhodococcus sp. IFP 2042 and Bradyrhizobium sp. IFP 2049 isolated from a polluted aquifer. Appl Microbiol Biotechnol 2013; 97:10531-9. [DOI: 10.1007/s00253-013-4803-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 02/20/2013] [Accepted: 02/21/2013] [Indexed: 11/26/2022]
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Constitutive expression of the cytochrome P450 EthABCD monooxygenase system enables degradation of synthetic dialkyl ethers in Aquincola tertiaricarbonis L108. Appl Environ Microbiol 2013; 79:2321-7. [PMID: 23354715 DOI: 10.1128/aem.03348-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Rhodococcus ruber IFP 2001, Rhodococcus zopfii IFP 2005, and Gordonia sp. strain IFP 2009, the cytochrome P450 monooxygenase EthABCD catalyzes hydroxylation of methoxy and ethoxy residues in the fuel oxygenates methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). The expression of the IS3-type transposase-flanked eth genes is ETBE dependent and controlled by the regulator EthR (C. Malandain et al., FEMS Microbiol. Ecol. 72:289-296, 2010). In contrast, we demonstrated by reverse transcription-quantitative PCR (RT-qPCR) that the betaproteobacterium Aquincola tertiaricarbonis L108, which possesses the ethABCD genes but lacks ethR, constitutively expresses the P450 system at high levels even when growing on nonether substrates, such as glucose. The mutant strain A. tertiaricarbonis L10, which is unable to degrade dialkyl ethers, resulted from a transposition event mediated by a rolling-circle IS91-type element flanking the eth gene cluster in the wild-type strain L108. The constitutive expression of Eth monooxygenase is likely initiated by the housekeeping sigma factor σ(70), as indicated by the presence in strain L108 of characteristic -10 and -35 binding sites upstream of ethA which are lacking in strain IFP 2001. This enables efficient degradation of diethyl ether, diisopropyl ether, MTBE, ETBE, TAME, and tert-amyl ethyl ether (TAEE) without any lag phase in strain L108. However, ethers with larger residues, n-hexyl methyl ether, tetrahydrofuran, and alkyl aryl ethers, were not attacked by the Eth system at significant rates in resting-cell experiments, indicating that the residue in the ether molecule which is not hydroxylated also contributes to the determination of substrate specificity.
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Hyman M. Biodegradation of gasoline ether oxygenates. Curr Opin Biotechnol 2012; 24:443-50. [PMID: 23116604 DOI: 10.1016/j.copbio.2012.10.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 09/17/2012] [Accepted: 10/03/2012] [Indexed: 10/27/2022]
Abstract
Ether oxygenates such as methyl tertiary butyl ether (MTBE) are added to gasoline to improve fuel combustion and decrease exhaust emissions. Ether oxygenates and their tertiary alcohol metabolites are now an important group of groundwater pollutants. This review highlights recent advances in our understanding of the microorganisms, enzymes and pathways involved in both the aerobic and anaerobic biodegradation of these compounds. This review also aims to illustrate how these microbiological and biochemical studies have guided, and have helped refine, molecular and stable isotope-based analytical approaches that are increasingly being used to detect and quantify biodegradation of these compounds in contaminated environments.
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Affiliation(s)
- Michael Hyman
- Department of Microbiology, North Carolina State University, Raleigh, NC 27695, USA.
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Kim DK, O'Shea KE, Cooper WJ. Oxidative degradation of alternative gasoline oxygenates in aqueous solution by ultrasonic irradiation: mechanistic study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2012; 430:246-259. [PMID: 22647393 DOI: 10.1016/j.scitotenv.2011.09.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 09/06/2011] [Accepted: 09/07/2011] [Indexed: 06/01/2023]
Abstract
Widespread pollution has been associated with gasoline oxygenates of branched ethers methyl tert-butyl ether (MTBE), di-isopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), and tert-amyl ether (TAME) which enter groundwater. The contaminated plume develops rapidly and treatment for the removal/destruction of these ethers is difficult when using conventional methods. Degradation of MTBE, with biological methods and advanced oxidation processes, are rather well known; however, fewer studies have been reported for degradation of alternative oxygenates. Degradation of alternative gasoline oxygenates (DIPE, ETBE, and TAME) by ultrasonic irradiation in aqueous oxygen saturation was investigated to elucidate degradation pathways. Detailed degradation mechanisms are proposed for each gasoline oxygenate. The common major degradation pathways are proposed to involve abstraction of α-hydrogen atoms by hydroxyl radicals generated during ultrasound cavitation and low temperature pyrolytic degradation of ETBE and TAME. Even some of the products from β-H abstraction overlap with those from high temperature pyrolysis, the effect of β-H abstraction was not shown clearly from product study because of possible 1,5 H-transfer inside cavitating bubbles. Formation of hydrogen peroxide and organic peroxides was also determined during sonolysis. These data provide a better understanding of the degradation pathways of gasoline oxygenates by sonolysis in aqueous solutions. The approach may also serve as a model for others interested in the details of sonolysis.
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Affiliation(s)
- Duk Kyung Kim
- Department of Physical Science, Auburn University Montgomery, Montgomery, AL 36117, United States
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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: 12] [Impact Index Per Article: 1.0] [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.
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Affiliation(s)
- Mònica Rosell
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig, Germany.
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Fayolle-Guichard F, Durand J, Cheucle M, Rosell M, Michelland RJ, Tracol JP, Le Roux F, Grundman G, Atteia O, Richnow HH, Dumestre A, Benoit Y. Study of an aquifer contaminated by ethyl tert-butyl ether (ETBE): site characterization and on-site bioremediation. JOURNAL OF HAZARDOUS MATERIALS 2012; 201-202:236-243. [PMID: 22177017 DOI: 10.1016/j.jhazmat.2011.11.074] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 10/18/2011] [Accepted: 11/22/2011] [Indexed: 05/31/2023]
Abstract
Ethyl tert-butyl ether (ETBE) was detected at high concentration (300mgL(-1)) in the groundwater below a gas-station. No significant carbon neither hydrogen isotopic fractionation of ETBE was detected along the plume. ETBE and BTEX biodegradation capacities of the indigenous microflora Pz1-ETBE and of a culture (MC-IFP) composed of Rhodococcus wratislaviensis IFP 2016, Rhodococcus aetherivorans IFP 2017 and Aquincola tertiaricarbonis IFP 2003 showed that ETBE and BTEX degradation rates were in the same range (ETBE: 0.91 and 0.83 mg L(-1)h(-1) and BTEX: 0.64 and 0.82 mg L(-1)h(-1), respectively) but tert-butanol (TBA) accumulated transiently at a high level using Pz1-ETBE (74 mg L(-1)). An on-site pilot plant (2m(3)) filled with polluted groundwater and inoculated by MC-IFP, successfully degraded four successive additions of ETBE and gasoline. However, an insignificant ETBE isotopic fractionation was also accompanying this decrease which suggested the involvement of low fractionating-strains using EthB enzymes, but required of additional proofs. The ethB gene encoding a cytochrome P450 involved in ETBE biodegradation (present in R. aetherivorans IFP 2017) was monitored by quantitative real-time polymerase chain reaction (q-PCR) on DNA extracted from water sampled in the pilot plant which yield up to 5×10(6) copies of ethB gene per L(-1).
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Bacterial degradation of tert-amyl alcohol proceeds via hemiterpene 2-methyl-3-buten-2-ol by employing the tertiary alcohol desaturase function of the Rieske nonheme mononuclear iron oxygenase MdpJ. J Bacteriol 2011; 194:972-81. [PMID: 22194447 DOI: 10.1128/jb.06384-11] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Tertiary alcohols, such as tert-butyl alcohol (TBA) and tert-amyl alcohol (TAA) and higher homologues, are only slowly degraded microbially. The conversion of TBA seems to proceed via hydroxylation to 2-methylpropan-1,2-diol, which is further oxidized to 2-hydroxyisobutyric acid. By analogy, a branched pathway is expected for the degradation of TAA, as this molecule possesses several potential hydroxylation sites. In Aquincola tertiaricarbonis L108 and Methylibium petroleiphilum PM1, a likely candidate catalyst for hydroxylations is the putative tertiary alcohol monooxygenase MdpJ. However, by comparing metabolite accumulations in wild-type strains of L108 and PM1 and in two mdpJ knockout mutants of strain L108, we could clearly show that MdpJ is not hydroxylating TAA to diols but functions as a desaturase, resulting in the formation of the hemiterpene 2-methyl-3-buten-2-ol. The latter is further processed via the hemiterpenes prenol, prenal, and 3-methylcrotonic acid. Likewise, 3-methyl-3-pentanol is degraded via 3-methyl-1-penten-3-ol. Wild-type strain L108 and mdpJ knockout mutants formed isoamylene and isoprene from TAA and 2-methyl-3-buten-2-ol, respectively. It is likely that this dehydratase activity is catalyzed by a not-yet-characterized enzyme postulated for the isomerization of 2-methyl-3-buten-2-ol and prenol. The vitamin requirements of strain L108 growing on TAA and the occurrence of 3-methylcrotonic acid as a metabolite indicate that TAA and hemiterpene degradation are linked with the catabolic route of the amino acid leucine, including an involvement of the biotin-dependent 3-methylcrotonyl coenzyme A (3-methylcrotonyl-CoA) carboxylase LiuBD. Evolutionary aspects of favored desaturase versus hydroxylation pathways for TAA conversion and the possible role of MdpJ in the degradation of higher tertiary alcohols are discussed.
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Purswani J, Juárez B, Rodelas B, Gónzalez-López J, Pozo C. Biofilm formation and microbial activity in a biofilter system in the presence of MTBE, ETBE and TAME. CHEMOSPHERE 2011; 85:616-624. [PMID: 21774959 DOI: 10.1016/j.chemosphere.2011.06.106] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 06/22/2011] [Accepted: 06/26/2011] [Indexed: 05/31/2023]
Abstract
Emerging water contaminants derived from unleaded gasoline such as methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME), are in need of effective bioremediation technologies for restoring water resources. In order to design the conditions of a future groundwater bioremediating biofilter, this work assesses the potential use of Acinetobacter calcoaceticus M10, Rhodococcus ruber E10 and Gordonia amicalis T3 for the removal of MTBE, ETBE and TAME in consortia or as individual strains. Biofilm formation on an inert polyethylene support material was assessed with scanning electron microscopy, and consortia were also analysed with fluorescent in situ hybridisation to examine the relation between the strains. A. calcoaceticus M10 was the best coloniser, followed by G. amicalis T3, however, biofilm formation of pair consortia favoured consortium M10-E10 both in formation and activity. However, degradation batch studies determined that neither consortium exhibited higher degradation than individual strain degradation. The physiological state of the three strains was also determined through flow cytometry using propidium iodide and 3'-dihexylocarbocyanine iodide thus gathering information on their viability and activity with the three oxygenates since previous microbial counts revealed slow growth. Strain E10 was observed to have the highest physiological activity in the presence of MTBE, and strain M10 activity with TAME was only maintained for 24 h, thus we believe that biotransformation of MTBE occurs within the active periods established by the cytometry analyses. Viable cell counts and oxygenate removal were determined in the presence of the metabolites tert-butyl alcohol (TBA) and tert-amyl alcohol (TAA), resulting in TBA biotransformation by M10 and E10, and TAA by M10. Our results show that A. calcoaceticus M10 and the consortium M10-E10 could be adequate inocula in MTBE and TAME bioremediating technologies.
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Affiliation(s)
- Jessica Purswani
- Environmental Microbiology Group, Institute of Water Research, Department of Microbiology, University of Granada, C/Ramón y Cajal no. 4, 18071 Granada, Spain
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Formation of alkenes via degradation of tert-alkyl ethers and alcohols by Aquincola tertiaricarbonis L108 and Methylibium spp. Appl Environ Microbiol 2011; 77:5981-7. [PMID: 21742915 DOI: 10.1128/aem.00093-11] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial degradation pathways of fuel oxygenates such as methyl tert-butyl and tert-amyl methyl ether (MTBE and TAME, respectively) have already been studied in some detail. However, many of the involved enzymes are still unknown, and possible side reactions have not yet been considered. In Aquincola tertiaricarbonis L108, Methylibium petroleiphilum PM1, and Methylibium sp. strain R8, we have now detected volatile hydrocarbons as by-products of the degradation of the tert-alkyl ether metabolites tert-butyl and tert-amyl alcohol (TBA and TAA, respectively). The alkene isobutene was formed only during TBA catabolism, while the beta and gamma isomers of isoamylene were produced only during TAA conversion. Both tert-alkyl alcohol degradation and alkene production were strictly oxygen dependent. However, the relative contribution of the dehydration reaction to total alcohol conversion increased with decreasing oxygen concentrations. In resting-cell experiments where the headspace oxygen content was adjusted to less than 2%, more than 50% of the TAA was converted to isoamylene. Isobutene formation from TBA was about 20-fold lower, reaching up to 4% alcohol turnover at low oxygen concentrations. It is likely that the putative tert-alkyl alcohol monooxygenase MdpJ, belonging to the Rieske nonheme mononuclear iron enzymes and found in all three strains tested, or an associated enzymatic step catalyzed the unusual elimination reaction. This was also supported by the detection of mdpJK genes in MTBE-degrading and isobutene-emitting enrichment cultures obtained from two treatment ponds operating at Leuna, Germany. The possible use of alkene formation as an easy-to-measure indicator of aerobic fuel oxygenate biodegradation in contaminated aquifers is discussed.
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Linking low-level stable isotope fractionation to expression of the cytochrome P450 monooxygenase-encoding ethB gene for elucidation of methyl tert-butyl ether biodegradation in aerated treatment pond systems. Appl Environ Microbiol 2010; 77:1086-96. [PMID: 21148686 DOI: 10.1128/aem.01698-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multidimensional compound-specific stable isotope analysis (CSIA) was applied in combination with RNA-based molecular tools to characterize methyl tertiary (tert-) butyl ether (MTBE) degradation mechanisms occurring in biofilms in an aerated treatment pond used for remediation of MTBE-contaminated groundwater. The main pathway for MTBE oxidation was elucidated by linking the low-level stable isotope fractionation (mean carbon isotopic enrichment factor [ε(C)] of -0.37‰ ± 0.05‰ and no significant hydrogen isotopic enrichment factor [ε(H)]) observed in microcosm experiments to expression of the ethB gene encoding a cytochrome P450 monooxygenase able to catalyze the oxidation of MTBE in biofilm samples both from the microcosms and directly from the ponds. 16S rRNA-specific primers revealed the presence of a sequence 100% identical to that of Methylibium petroleiphilum PM1, a well-characterized MTBE degrader. However, neither expression of the mdpA genes encoding the alkane hydroxylase-like enzyme responsible for MTBE oxidation in this strain nor the related MTBE isotope fractionation pattern produced by PM1 could be detected, suggesting that this enzyme was not active in this system. Additionally, observed low inverse fractionation of carbon (ε(C) of +0.11‰ ± 0.03‰) and low fractionation of hydrogen (ε(H) of -5‰ ± 1‰) in laboratory experiments simulating MTBE stripping from an open surface water body suggest that the application of CSIA in field investigations to detect biodegradation may lead to false-negative results when volatilization effects coincide with the activity of low-fractionating enzymes. As shown in this study, complementary examination of expression of specific catabolic genes can be used as additional direct evidence for microbial degradation activity and may overcome this problem.
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Assessment of MTBE biodegradation pathways by two-dimensional isotope analysis in mixed bacterial consortia under different redox conditions. Appl Microbiol Biotechnol 2010; 88:309-17. [DOI: 10.1007/s00253-010-2730-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 06/02/2010] [Accepted: 06/12/2010] [Indexed: 11/27/2022]
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Identification and analysis of the biosynthetic gene cluster encoding the thiopeptide antibiotic cyclothiazomycin in Streptomyces hygroscopicus 10-22. Appl Environ Microbiol 2010; 76:2335-44. [PMID: 20154110 DOI: 10.1128/aem.01790-09] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thiopeptide antibiotics are an important class of natural products resulting from posttranslational modifications of ribosomally synthesized peptides. Cyclothiazomycin is a typical thiopeptide antibiotic that has a unique bridged macrocyclic structure derived from an 18-amino-acid structural peptide. Here we reported cloning, sequencing, and heterologous expression of the cyclothiazomycin biosynthetic gene cluster from Streptomyces hygroscopicus 10-22. Remarkably, successful heterologous expression of a 22.7-kb gene cluster in Streptomyces lividans 1326 suggested that there is a minimum set of 15 open reading frames that includes all of the functional genes required for cyclothiazomycin production. Six genes of these genes, cltBCDEFG flanking the structural gene cltA, were predicted to encode the enzymes required for the main framework of cyclothiazomycin, and two enzymes encoded by a putative operon, cltMN, were hypothesized to participate in the tailoring step to generate the tertiary thioether, leading to the final cyclization of the bridged macrocyclic structure. This rigorous bioinformatics analysis based on heterologous expression of cyclothiazomycin resulted in an ideal biosynthetic model for us to understand the biosynthesis of thiopeptides.
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Malandain C, Fayolle-Guichard F, Vogel TM. Cytochromes P450-mediated degradation of fuel oxygenates by environmental isolates. FEMS Microbiol Ecol 2010; 72:289-96. [PMID: 20337704 DOI: 10.1111/j.1574-6941.2010.00847.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The degradation of fuel oxygenates [methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME)] by Rhodococcus ruber IFP 2001, Rhodococcus zopfii IFP 2005 and Gordonia sp. IFP 2009 (formerly Mycobacterium sp.) isolated from different environments was compared. Strains IFP 2001, IFP 2005 and IFP 2009 grew on ETBE due in part to the activity of a cytochrome P450, CYP249. All of these strains were able to degrade ETBE to tert-butyl alcohol and are harboring the CYP249 cytochrome P450. They were also able to degrade MTBE and TAME, but ETBE was degraded in all cases most efficiently, with degradation rates measured after growth on ETBE of 2.1, 3.5 and 1.6 mmol ETBE g(-1) dry weight h(-1) for strains IFP 2001, IFP 2005 and IFP 2009, respectively. The phylogenetic relationships between the different ethR (encoding the regulator) and ethB (encoding the cytochrome P450) genes were determined and showed high identity between different ethB genes (>99%). Only ETBE was able to induce the expression of ethB in strains IFP 2001 and IFP 2005 as measured by reverse transcriptase quantitative PCR. Our results are a first indication of the possible role played by the ethB gene in the ecology of ETBE degradation.
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Ehrlich KC, Chang PK, Scharfenstein LL, Cary JW, Crawford JM, Townsend CA. Absence of the aflatoxin biosynthesis gene, norA, allows accumulation of deoxyaflatoxin B1 in Aspergillus flavus cultures. FEMS Microbiol Lett 2010; 305:65-70. [PMID: 20158523 DOI: 10.1111/j.1574-6968.2010.01914.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Biosynthesis of the highly toxic and carcinogenic aflatoxins in select Aspergillus species from the common intermediate O-methylsterigmatocystin has been postulated to require only the cytochrome P450 monooxygenase, OrdA (AflQ). We now provide evidence that the aryl alcohol dehydrogenase NorA (AflE) encoded by the aflatoxin biosynthetic gene cluster in Aspergillus flavus affects the accumulation of aflatoxins in the final steps of aflatoxin biosynthesis. Mutants with inactive norA produced reduced quantities of aflatoxin B(1) (AFB(1)), but elevated quantities of a new metabolite, deoxyAFB(1). To explain this result, we suggest that, in the absence of NorA, the AFB(1) reduction product, aflatoxicol, is produced and is readily dehydrated to deoxyAFB(1) in the acidic medium, enabling us to observe this otherwise minor toxin produced in wild-type A. flavus.
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Affiliation(s)
- Kenneth C Ehrlich
- Southern Regional Research Center, ARS/USDA, New Orleans, LA 70179, USA.
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Auffret M, Labbé D, Thouand G, Greer CW, Fayolle-Guichard F. Degradation of a mixture of hydrocarbons, gasoline, and diesel oil additives by Rhodococcus aetherivorans and Rhodococcus wratislaviensis. Appl Environ Microbiol 2009; 75:7774-82. [PMID: 19837842 PMCID: PMC2794095 DOI: 10.1128/aem.01117-09] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Accepted: 10/06/2009] [Indexed: 11/20/2022] Open
Abstract
Two strains, identified as Rhodococcus wratislaviensis IFP 2016 and Rhodococcus aetherivorans IFP 2017, were isolated from a microbial consortium that degraded 15 petroleum compounds or additives when provided in a mixture containing 16 compounds (benzene, toluene, ethylbenzene, m-xylene, p-xylene, o-xylene, octane, hexadecane, 2,2,4-trimethylpentane [isooctane], cyclohexane, cyclohexanol, naphthalene, methyl tert-butyl ether [MTBE], ethyl tert-butyl ether [ETBE], tert-butyl alcohol [TBA], and 2-ethylhexyl nitrate [2-EHN]). The strains had broad degradation capacities toward the compounds, including the more recalcitrant ones, MTBE, ETBE, isooctane, cyclohexane, and 2-EHN. R. wratislaviensis IFP 2016 degraded and mineralized to different extents 11 of the compounds when provided individually, sometimes requiring 2,2,4,4,6,8,8-heptamethylnonane (HMN) as a cosolvent. R. aetherivorans IFP 2017 degraded a reduced spectrum of substrates. The coculture of the two strains degraded completely 13 compounds, isooctane and 2-EHN were partially degraded (30% and 73%, respectively), and only TBA was not degraded. Significant MTBE and ETBE degradation rates, 14.3 and 116.1 mumol of ether degraded h(-1) g(-1) (dry weight), respectively, were measured for R. aetherivorans IFP 2017. The presence of benzene, toluene, ethylbenzene, and xylenes (BTEXs) had a detrimental effect on ETBE and MTBE biodegradation, whereas octane had a positive effect on the MTBE biodegradation by R. wratislaviensis IFP 2016. BTEXs had either beneficial or detrimental effects on their own degradation by R. wratislaviensis IFP 2016. Potential genes involved in hydrocarbon degradation in the two strains were identified and partially sequenced.
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Affiliation(s)
- Marc Auffret
- Institut Français du Pétrole (IFP), 1-4 Avenue de Bois-Préau, F-92852 Rueil-Malmaison, France, National Research Council, Biotechnology Research Institute (NRC-BRI), 6100 Royalmount Avenue, Montréal, Québec H4P 2R2, Canada, Université de Nantes, UMR CNRS GEPEA, IUT 18, Boulevard Gaston Deferre, F-85035 La Roche-sur-Yon, France
| | - Diane Labbé
- Institut Français du Pétrole (IFP), 1-4 Avenue de Bois-Préau, F-92852 Rueil-Malmaison, France, National Research Council, Biotechnology Research Institute (NRC-BRI), 6100 Royalmount Avenue, Montréal, Québec H4P 2R2, Canada, Université de Nantes, UMR CNRS GEPEA, IUT 18, Boulevard Gaston Deferre, F-85035 La Roche-sur-Yon, France
| | - Gérald Thouand
- Institut Français du Pétrole (IFP), 1-4 Avenue de Bois-Préau, F-92852 Rueil-Malmaison, France, National Research Council, Biotechnology Research Institute (NRC-BRI), 6100 Royalmount Avenue, Montréal, Québec H4P 2R2, Canada, Université de Nantes, UMR CNRS GEPEA, IUT 18, Boulevard Gaston Deferre, F-85035 La Roche-sur-Yon, France
| | - Charles W. Greer
- Institut Français du Pétrole (IFP), 1-4 Avenue de Bois-Préau, F-92852 Rueil-Malmaison, France, National Research Council, Biotechnology Research Institute (NRC-BRI), 6100 Royalmount Avenue, Montréal, Québec H4P 2R2, Canada, Université de Nantes, UMR CNRS GEPEA, IUT 18, Boulevard Gaston Deferre, F-85035 La Roche-sur-Yon, France
| | - Françoise Fayolle-Guichard
- Institut Français du Pétrole (IFP), 1-4 Avenue de Bois-Préau, F-92852 Rueil-Malmaison, France, National Research Council, Biotechnology Research Institute (NRC-BRI), 6100 Royalmount Avenue, Montréal, Québec H4P 2R2, Canada, Université de Nantes, UMR CNRS GEPEA, IUT 18, Boulevard Gaston Deferre, F-85035 La Roche-sur-Yon, France
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Amouric A, Quéméneur M, Grossi V, Liebgott PP, Auria R, Casalot L. Identification of different alkane hydroxylase systems inRhodococcus ruberstrain SP2B, an hexane-degrading actinomycete. J Appl Microbiol 2009; 108:1903-16. [DOI: 10.1111/j.1365-2672.2009.04592.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Ehrlich KC. Predicted roles of the uncharacterized clustered genes in aflatoxin biosynthesis. Toxins (Basel) 2009; 1:37-58. [PMID: 22069531 PMCID: PMC3202775 DOI: 10.3390/toxins1010037] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 09/22/2009] [Accepted: 09/24/2009] [Indexed: 11/21/2022] Open
Abstract
Biosynthesis of the toxic and carcinogenic aflatoxins (AFs) requires the activity of more than 27 enzymes. The roles in biosynthesis of newly described enzymes are discussed in this review. We suggest that HypC catalyzes the oxidation of norsolorinic acid anthrone; AvfA (AflI), the ring-closure step in formation of hydroxyversicolorone; HypB, the second oxidation step in conversion of O-methylsterigmatocystin to AF; and HypE and NorA (AflE), the final two steps in AFB(1) formation. HypD, an integral membrane protein, affects fungal development and lowers AF production while AflJ (AflS), has a partial methyltransferase domain that may be important in its function as a transcriptional co-activator.
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Affiliation(s)
- Kenneth C Ehrlich
- Southern Regional Research Center, ARS, USDA/1100 Robert E. Lee Blvd, New Orleans, LA 70124, USA.
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Sequence analysis and heterologous expression of a new cytochrome P450 monooxygenase from Rhodococcus sp. for asymmetric sulfoxidation. Appl Microbiol Biotechnol 2009; 85:615-24. [PMID: 19633839 DOI: 10.1007/s00253-009-2118-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2009] [Revised: 06/15/2009] [Accepted: 06/30/2009] [Indexed: 10/20/2022]
Abstract
In this study, a 3.7-kb DNA fragment was cloned from Rhodococcus sp. ECU0066, and the sequence was analyzed. It was revealed that the largest one (2,361 bp) of this gene fragment encodes a protein consisting of 787 amino acids, with 73% identity to P450RhF (accession number AF45924) from Rhodococcus sp. NCIMB 9784. The gene of this new P450 monooxygenase (named as P450SMO) was successfully expressed in Escherichia coli BL21 (DE3), and the enzyme was also purified and characterized. In the presence of reduced nicotinamide adenine dinucleotide phosphate, the enzyme showed significant sulfoxidation activity towards several sulfides, with (S)-sulfoxides as the predominant product. The p-chlorothioanisole, p-fluorothioanisole, p-tolyl methyl sulfide, and p-methoxythioanisole showed relatively higher activities than the other sulfides, but the stereoselectivity for p-methoxythioanisole was much lower. The optimal activity of the purified enzyme toward p-chlorothioanisole occurred at pH 7.0 and 30 degrees C. The current study is the first to report a recombinant cytochrome P450 enzyme of Rhodococcus sp. which is responsible for the asymmetric oxidation of sulfides. The new enzymatic activity of P450SMO on the above compounds makes it an attractive biocatalyst for asymmetric synthesis of enantiopure sulfoxides.
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Müller RH, Rohwerder T, Harms H. Degradation of fuel oxygenates and their main intermediates by Aquincola tertiaricarbonis L108. MICROBIOLOGY-SGM 2008; 154:1414-1421. [PMID: 18451050 DOI: 10.1099/mic.0.2007/014159-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Growth of Aquincola tertiaricarbonis L108 on the fuel oxygenates methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME), as well as on their main metabolites tert-butyl alcohol (TBA), tert-amyl alcohol (TAA) and 2-hydroxyisobutyrate (2-HIBA) was systematically investigated to characterize the range and rates of oxygenate degradation by this strain. The effective maximum growth rates for MTBE, ETBE and TAME at pH 7 and 30 degrees C were 0.045 h(-1), 0.06 h(-1) and 0.055 h(-1), respectively, whereas TAA, TBA and 2-HIBA permitted growth at rates up to 0.08 h(-1), 0.1 h(-1) and 0.17 h(-1), respectively. The experimental growth yields with all these substrates were high. Yields of 0.55 g dry mass (dm) (g MTBE)(-1), 0.53 g dm (g ETBE)(-1), 0.81 g dm (g TAME)(-1), 0.48 g dm (g TBA)(-1), 0.76 g dm (g TAA)(-1) and 0.54 g dm (g 2-HIBA)(-1) were obtained. Maximum specific degradation rates were 0.92 mmol MTBE h(-1) (g dm)(-1), 1.11 mmol ETBE h(-1) g(-1), 0.66 mmol TAME h(-1) g(-1), 1.19 mmol TAA h(-1) g(-1), 2.82 mmol TBA h(-1) g(-1), and 3.27 mmol 2-HIBA h(-1) g(-1). The relatively high rates with TBA, TAA and 2-HIBA indicate that the transformations of these metabolites did not limit the metabolism of MTBE and the related ether compounds. Despite the fact that these metabolites still carry a tertiary carbon atom that is commonly suspected to confer recalcitrance to the ether oxygenates, the transformation rates were in the same range as those with succinate and fructose. With MTBE, strain L108 grew at pHs between 5.5 and 8.0 at near-maximal rate, whereas no growth was found below pH 5.0 and above pH 9.0. The optimum growth temperature was 30 degrees C, but at 5 degrees C still about 15 % of the maximum rate remained, whereas no growth occurred at 42 degrees C. This indicates that MTBE metabolites are valuable substrates and that A. tertiaricarbonis L108 is a good candidate for bioremediation purposes. The possible origin of its exceptional metabolic capability is discussed in terms of the evolution of enzymic activities involved in the conversion of compounds carrying tertiary butyl groups.
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Affiliation(s)
- Roland H Müller
- UFZ, Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstr. 15, D-04318 Leipzig, Germany
| | - Thore Rohwerder
- Aquatic Biotechnology, Biofilm Centre, University Duisburg-Essen, Geibelstr. 41, D-47057 Duisburg, Germany
| | - Hauke Harms
- UFZ, Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstr. 15, D-04318 Leipzig, Germany
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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]
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Soanes DM, Alam I, Cornell M, Wong HM, Hedeler C, Paton NW, Rattray M, Hubbard SJ, Oliver SG, Talbot NJ. Comparative genome analysis of filamentous fungi reveals gene family expansions associated with fungal pathogenesis. PLoS One 2008; 3:e2300. [PMID: 18523684 PMCID: PMC2409186 DOI: 10.1371/journal.pone.0002300] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Accepted: 04/15/2008] [Indexed: 12/30/2022] Open
Abstract
Fungi and oomycetes are the causal agents of many of the most serious diseases of plants. Here we report a detailed comparative analysis of the genome sequences of thirty-six species of fungi and oomycetes, including seven plant pathogenic species, that aims to explore the common genetic features associated with plant disease-causing species. The predicted translational products of each genome have been clustered into groups of potential orthologues using Markov Chain Clustering and the data integrated into the e-Fungi object-oriented data warehouse (http://www.e-fungi.org.uk/). Analysis of the species distribution of members of these clusters has identified proteins that are specific to filamentous fungal species and a group of proteins found only in plant pathogens. By comparing the gene inventories of filamentous, ascomycetous phytopathogenic and free-living species of fungi, we have identified a set of gene families that appear to have expanded during the evolution of phytopathogens and may therefore serve important roles in plant disease. We have also characterised the predicted set of secreted proteins encoded by each genome and identified a set of protein families which are significantly over-represented in the secretomes of plant pathogenic fungi, including putative effector proteins that might perturb host cell biology during plant infection. The results demonstrate the potential of comparative genome analysis for exploring the evolution of eukaryotic microbial pathogenesis.
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Affiliation(s)
- Darren M. Soanes
- School of Biosciences, Geoffrey Pope Building, University of Exeter, Exeter, United Kingdom
| | - Intikhab Alam
- School of Computer Science, University of Manchester, Manchester, United Kingdom
| | - Mike Cornell
- School of Computer Science, University of Manchester, Manchester, United Kingdom
| | - Han Min Wong
- School of Biosciences, Geoffrey Pope Building, University of Exeter, Exeter, United Kingdom
| | - Cornelia Hedeler
- School of Computer Science, University of Manchester, Manchester, United Kingdom
| | - Norman W. Paton
- School of Computer Science, University of Manchester, Manchester, United Kingdom
| | - Magnus Rattray
- School of Computer Science, University of Manchester, Manchester, United Kingdom
| | - Simon J. Hubbard
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Manchester, United Kingdom
| | - Stephen G. Oliver
- Department of Biochemistry, University of Cambridge, Sanger Building, Cambridge, United Kingdom
| | - Nicholas J. Talbot
- School of Biosciences, Geoffrey Pope Building, University of Exeter, Exeter, United Kingdom
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Sasaki M, Tsuchido T, Matsumura Y. Molecular cloning and characterization of cytochrome P450 and ferredoxin genes involved in bisphenol A degradation in Sphingomonas bisphenolicum strain AO1. J Appl Microbiol 2008; 105:1158-69. [PMID: 18492046 DOI: 10.1111/j.1365-2672.2008.03843.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To clone and characterize the genes bisdA and bisdB, encoding Ferredoxin(bisd) (Fd(bisd)) and cytochrome P450(bisd) (P450(bisd)), respectively, from the bisphenol A (BPA) degrading Sphingomonas bisphenolicum strain AO1. METHODS AND RESULTS The 3.7 kb region containing bisdA and bisdB was cloned by genome walking and colony hybridization. The deduced N-terminal amino acid sequences of bisdA and bisdB were consistent with those of Fd(bisd) and P450(bisd) proteins characterized in our previous report. Two transposase genes, tnpA1 and tnpA2, were also located upstream and downstream of bisdAB. From amino acid sequence analysis, P450(bisd) has two conserved regions corresponding to the oxygen and heme binding regions of the bacterial cytochrome P450 family. Fd(bisd) was similar to putidaredoxin-type [2Fe-2S] ferredoxins. Escherichia coli BL21 (DE3) cells bearing bisdB- and bisdAB-recombinant pET19b were able to degrade BPA. A spontaneous mutant, strain AO1L, which was unable to degrade BPA, was isolated from the stock culture, and it was confirmed that strain AO1L had no bisdAB region. CONCLUSIONS P450(bisd) monooxygenase sytem, encoded by bisdAB, is one system required for BPA hydroxylation in S. bisphenolicum strain AO1. SIGNIFICANCE AND IMPACT OF THE STUDY Our results indicate that bisdAB are key genes for BPA degradation in S. bisphenolicum strain AO1.
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Affiliation(s)
- M Sasaki
- Department of Life Science and Biotechnology, Kansai University, Suita, Osaka, Japan
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50
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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
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