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Sharma M, Khurana H, Singh DN, Negi RK. The genus Sphingopyxis: Systematics, ecology, and bioremediation potential - A review. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 280:111744. [PMID: 33280938 DOI: 10.1016/j.jenvman.2020.111744] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 11/22/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
The genus Sphingopyxis was first reported in the year 2001. Phylogenetically, Sphingopyxis is well delineated from other genera Sphingobium, Sphingomonas and Novosphingobium of sphingomonads group, family Sphingomonadaceae of Proteobacteria. To date (at the time of writing), the genus Sphingopyxis comprises of twenty validly published species available in List of Prokaryotic Names with Standing in Nomenclature. Sphingopyxis spp. have been isolated from diverse niches including, agricultural soil, marine and fresh water, caves, activated sludge, thermal spring, oil and pesticide contaminated soil, and heavy metal contaminated sites. Sphingopyxis species have drawn considerable attention not only for their ability to survive under extreme environments, but also for their potential to degrade number of xenobiotics and other environmental contaminants that impose serious threat to human health. At present, genome sequence of both cultivable and non-cultivable strains (metagenome assembled genome) are available in the public databases (NCBI) and genome wide studies confirms the presence of mobile genetic elements and plethora of degradation genes and pathways making them a potential candidate for bioremediation. Beside genome wide predictions there are number of experimental evidences confirm the degradation potential of bacteria belonging to genus Sphingopyxis and also the production of different secondary metabolites that help them interact and survive in their ecological niches. This review provides detailed information on ecology, general characteristic and the significant implications of Sphingopyxis species in environmental management along with the bio-synthetic potential.
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Affiliation(s)
- Monika Sharma
- Fish Molecular Biology Laboratory, Department of Zoology, University of Delhi, Delhi-110007, India
| | - Himani Khurana
- Fish Molecular Biology Laboratory, Department of Zoology, University of Delhi, Delhi-110007, India
| | - Durgesh Narain Singh
- Bacterial Pathogenesis Laboratory, Department of Zoology, University of Delhi, Delhi-110007, India
| | - Ram Krishan Negi
- Fish Molecular Biology Laboratory, Department of Zoology, University of Delhi, Delhi-110007, India.
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García-Romero I, Nogales J, Díaz E, Santero E, Floriano B. Understanding the metabolism of the tetralin degrader Sphingopyxis granuli strain TFA through genome-scale metabolic modelling. Sci Rep 2020; 10:8651. [PMID: 32457330 PMCID: PMC7250832 DOI: 10.1038/s41598-020-65258-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/30/2020] [Indexed: 11/23/2022] Open
Abstract
Sphingopyxis granuli strain TFA is an α-proteobacterium that belongs to the sphingomonads, a group of bacteria well-known for its degradative capabilities and oligotrophic metabolism. Strain TFA is the only bacterium in which the mineralisation of the aromatic pollutant tetralin has been completely characterized at biochemical, genetic, and regulatory levels and the first Sphingopyxis characterised as facultative anaerobe. Here we report additional metabolic features of this α-proteobacterium using metabolic modelling and the functional integration of genomic and transcriptomic data. The genome-scale metabolic model (GEM) of strain TFA, which has been manually curated, includes information on 743 genes, 1114 metabolites and 1397 reactions. This represents the largest metabolic model for a member of the Sphingomonadales order thus far. The predictive potential of this model was validated against experimentally calculated growth rates on different carbon sources and under different growth conditions, including both aerobic and anaerobic metabolisms. Moreover, new carbon and nitrogen sources were predicted and experimentally validated. The constructed metabolic model was used as a platform for the incorporation of transcriptomic data, generating a more robust and accurate model. In silico flux analysis under different metabolic scenarios highlighted the key role of the glyoxylate cycle in the central metabolism of strain TFA.
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Affiliation(s)
- Inmaculada García-Romero
- Centro Andaluz de Biología del Desarrollo, CSIC-Universidad Pablo de Olavide, ES-41013, Seville, Spain
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, BT9 7BL, United Kingdom
| | - Juan Nogales
- Department of Systems Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), 28049, Madrid, Spain
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), Madrid, Spain
| | - Eduardo Díaz
- Department of Microbial and Plant Biotechnology. Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CIB-CSIC), 28040, Madrid, Spain
| | - Eduardo Santero
- Centro Andaluz de Biología del Desarrollo, CSIC-Universidad Pablo de Olavide, ES-41013, Seville, Spain
| | - Belén Floriano
- Department of Molecular Biology and Biochemical Engineering. Universidad Pablo de Olavide, ES-41013, Seville, Spain.
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Ullah M, Weng CH, Li H, Sun SW, Zhang H, Song AH, Zhu H. Degradation of polyvinyl alcohol by a novel bacterial strain Stenotrophomonas sp. SA21. ENVIRONMENTAL TECHNOLOGY 2018; 39:2056-2061. [PMID: 28669293 DOI: 10.1080/09593330.2017.1349189] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
UNLABELLED In this study, polyvinyl alcohol (PVA)-degrading bacteria were screened from oil sludge using PVA as a sole source of carbon in the culture medium. A novel strain, SA21, was obtained and identified as a member of the Stenotrophomonas genus based on the analysis of a partial 16S rDNA nucleotide sequence, morphological and biochemical characteristics, and phylogenetic analysis. This Stenotrophomonas isolate had not previously been reported as a PVA-degrading bacterium. Stenotrophomonas sp. strain SA21 degraded 90% of the PVA present in the culture medium after 4 days. The effect of nitrogen sources on the production of PVA-degrading enzyme involved in the biodegradation process was significant, and the enzymatic activity reached 82 U/ml when ammonium nitrate or urea was used in the optimized medium. The information obtained in this study will provide a foundation for improving industrial wastewater treatment. ABBREVIATIONS DCW: dry cell weight; FTIR: Fourier Transform Infrared Spectroscopy; NCBI: National Center for Biotechnology Information; PCR: polymerase chain reaction; PVA: polyvinyl alcohol; SEM: scanning electron microscope.
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Affiliation(s)
- Munzer Ullah
- a Centre for Bioengineering and Biotechnology , China University of Petroleum (East China) , Qingdao , People's Republic of China
| | - Cai-Hong Weng
- a Centre for Bioengineering and Biotechnology , China University of Petroleum (East China) , Qingdao , People's Republic of China
| | - Hui Li
- a Centre for Bioengineering and Biotechnology , China University of Petroleum (East China) , Qingdao , People's Republic of China
| | - Shi-Wei Sun
- a Centre for Bioengineering and Biotechnology , China University of Petroleum (East China) , Qingdao , People's Republic of China
| | - Hong Zhang
- a Centre for Bioengineering and Biotechnology , China University of Petroleum (East China) , Qingdao , People's Republic of China
| | - Ai-Huan Song
- b Marine Biology Institute of Shandong Province , Qingdao , People's Republic of China
| | - Hu Zhu
- a Centre for Bioengineering and Biotechnology , China University of Petroleum (East China) , Qingdao , People's Republic of China
- c College of Chemistry and Chemical Engineering , Fujian Normal University , Fuzhou , People's Republic of China
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Bioinformatics Analysis and Characterization of Highly Efficient Polyvinyl Alcohol (PVA)-Degrading Enzymes from the Novel PVA Degrader Stenotrophomonas rhizophila QL-P4. Appl Environ Microbiol 2017; 84:AEM.01898-17. [PMID: 29079625 DOI: 10.1128/aem.01898-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 10/23/2017] [Indexed: 01/24/2023] Open
Abstract
Polyvinyl alcohol (PVA) is used widely in industry, and associated environmental pollution is a serious problem. Herein, we report a novel, efficient PVA degrader, Stenotrophomonas rhizophila QL-P4, isolated from fallen leaves from a virgin forest in the Qinling Mountains. The complete genome was obtained using single-molecule real-time (SMRT) technology and corrected using Illumina sequencing. Bioinformatics analysis revealed eight PVA/vinyl alcohol oligomer (OVA)-degrading genes. Of these, seven genes were predicted to be involved in the classic intracellular PVA/OVA degradation pathway, and one (BAY15_3292) was identified as a novel PVA oxidase. Five PVA/OVA-degrading enzymes were purified and characterized. One of these, BAY15_1712, a PVA dehydrogenase (PVADH), displayed high catalytic efficiency toward PVA and OVA substrate. All reported PVADHs only have PVA-degrading ability. Most importantly, we discovered a novel PVA oxidase (BAY15_3292) that exhibited higher PVA-degrading efficiency than the reported PVADHs. Further investigation indicated that BAY15_3292 plays a crucial role in PVA degradation in S. rhizophila QL-P4. Knocking out BAY15_3292 resulted in a significant decline in PVA-degrading activity in S. rhizophila QL-P4. Interestingly, we found that BAY15_3292 possesses exocrine activity, which distinguishes it from classic PVADHs. Transparent circle experiments further proved that BAY15_3292 greatly affects extracellular PVA degradation in S. rhizophila QL-P4. The exocrine characteristics of BAY15_3292 facilitate its potential application to PVA bioremediation. In addition, we report three new efficient secondary alcohol dehydrogenases (SADHs) with OVA-degrading ability in S. rhizophila QL-P4; in contrast, only one OVA-degrading SADH was reported previously.IMPORTANCE With the widespread application of PVA in industry, PVA-related environmental pollution is an increasingly serious issue. Because PVA is difficult to degrade, it accumulates in aquatic environments and causes chronic toxicity to aquatic organisms. Biodegradation of PVA, as an economical and environment-friendly method, has attracted much interest. To date, effective and applicable PVA-degrading bacteria/enzymes have not been reported. Herein, we report a new efficient PVA degrader (S. rhizophila QL-P4) that has five PVA/OVA-degrading enzymes with high catalytic efficiency, among which BAY15_1712 is the only reported PVADH with both PVA- and OVA-degrading abilities. Importantly, we discovered a novel PVA oxidase (BAY15_3292) that is not only more efficient than other reported PVA-degrading PVADHs but also has exocrine activity. Overall, our findings provide new insight into PVA-degrading pathways in microorganisms and suggest S. rhizophila QL-P4 and its enzymes have the potential for application to PVA bioremediation to reduce or eliminate PVA-related environmental pollution.
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Ghobadi S, Mehraeen S, Bakhtiari R, Shamloo B, Sadhu V, Papila M, Cebeci FÇ, Gürsel SA. PVA/PANI/rGO ternary electrospun mats as metal-free anti-bacterial substrates. RSC Adv 2016. [DOI: 10.1039/c6ra16785c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Successful performance of biocompatible hybrid systems in various biomedical applications such as wound healing patches, and scaffolds for stem cell preparation have been reported.
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Affiliation(s)
- Sajjad Ghobadi
- Faculty of Engineering and Natural Sciences
- Sabanci University
- 34956 Istanbul
- Turkey
| | - Shayan Mehraeen
- Faculty of Engineering and Natural Sciences
- Sabanci University
- 34956 Istanbul
- Turkey
| | - Rokhsareh Bakhtiari
- Faculty of Engineering and Natural Sciences
- Sabanci University
- 34956 Istanbul
- Turkey
| | - Bahar Shamloo
- Faculty of Engineering and Natural Sciences
- Sabanci University
- 34956 Istanbul
- Turkey
| | - Veera Sadhu
- Sabanci University Nanotechnology Research and Application Center (SUNUM)
- Sabanci University
- 34956 Istanbul
- Turkey
| | - Melih Papila
- Faculty of Engineering and Natural Sciences
- Sabanci University
- 34956 Istanbul
- Turkey
| | - Fevzi Çakmak Cebeci
- Faculty of Engineering and Natural Sciences
- Sabanci University
- 34956 Istanbul
- Turkey
- Sabanci University Nanotechnology Research and Application Center (SUNUM)
| | - Selmiye Alkan Gürsel
- Faculty of Engineering and Natural Sciences
- Sabanci University
- 34956 Istanbul
- Turkey
- Sabanci University Nanotechnology Research and Application Center (SUNUM)
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Complete Genome Sequence of Polyvinyl Alcohol-Degrading Strain Sphingopyxis sp. 113P3 (NBRC 111507). GENOME ANNOUNCEMENTS 2015; 3:3/5/e01169-15. [PMID: 26472829 PMCID: PMC4611681 DOI: 10.1128/genomea.01169-15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Strain 113P3 was isolated from activated sludge and identified as a polyvinyl alcohol (PVA)-degrading Pseudomonas species; it was later reidentified as Sphingopyxis species. Only three genes are directly relevant to the metabolism of PVA and comprise the pva operon, which was deposited as accession no. AB190228. Here, we report the complete genome sequence of strain 113P3, which has been conserved as a stock culture (NBRC 111507) at the Biological Resource Center, National Institute of Technology and Evaluation (NITE) (Tokyo, Japan). The genome of strain 113P3 is composed of a 4.4-Mb circular chromosome and a 243-kb plasmid. The whole finishing was conducted in silico except for four PCRs. The sequence corresponding to AB190288 exists on the chromosome.
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Stolz A. Degradative plasmids from sphingomonads. FEMS Microbiol Lett 2013; 350:9-19. [DOI: 10.1111/1574-6968.12283] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/05/2013] [Accepted: 09/09/2013] [Indexed: 12/15/2022] Open
Affiliation(s)
- Andreas Stolz
- Institut für Mikrobiologie; Universität Stuttgart; Stuttgart Germany
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Wongwongsee W, Chareanpat P, Pinyakong O. Abilities and genes for PAH biodegradation of bacteria isolated from mangrove sediments from the central of Thailand. MARINE POLLUTION BULLETIN 2013; 74:95-104. [PMID: 23928000 DOI: 10.1016/j.marpolbul.2013.07.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 07/11/2013] [Accepted: 07/12/2013] [Indexed: 06/02/2023]
Abstract
PAH-degrading bacteria, including Novosphingobium sp. PCY, Microbacterium sp. BPW, Ralstonia sp. BPH, Alcaligenes sp. SSK1B, and Achromobacter sp. SSK4, were isolated from mangrove sediments. These isolates degraded 50-76% of 100 mg/l phenanthrene within 2 weeks. Strains PCY and BPW also degraded pyrene at 98% and 71%, respectively. Furthermore, all of them probably produced biosurfactants in the presence of hydrocarbons. Interestingly, PCY has a versatility to degrade various PAHs. Molecular techniques and plasmid curing remarkably revealed the presence of the alpha subunit of pyrene dioxygenase gene (nidA), involving in its pyrene/phenanthrene degrading ability, located on megaplasmid of PCY which has never before been reported in sphingomonads. Moreover, genes encoding ferredoxin, reductase, extradiol dioxygenase (bphA3A4C) and exopolysaccharide biosynthetase, which may be involved in PAH degradation and biosurfactant production, were also found in PCY. Therefore, we conclude that these isolates, especially PCY, can be the candidates for use as inoculums in the bioremediation.
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Affiliation(s)
- Wanwasan Wongwongsee
- Microbiology Program in Science, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand.
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Jia D, Li J, Liu L, Zhang D, Yang Y, Du G, Chen J. High-level expression, purification, and enzymatic characterization of truncated poly(vinyl alcohol) dehydrogenase in methylotrophic yeast Pichia pastoris. Appl Microbiol Biotechnol 2012; 97:1113-20. [PMID: 22406863 DOI: 10.1007/s00253-012-3986-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 02/11/2012] [Accepted: 02/17/2012] [Indexed: 11/30/2022]
Abstract
A 1,965-bp fragment encoding a poly(vinyl alcohol) dehydrogenase (PVADH) from Sphingopyxis sp. 113P3 was synthesized based on the codon bias of the methylotrophic yeast Pichia pastoris. The fragment was then amplified by polymerase chain reaction and inserted into the site between EcoRI and NotI sites in pPIC9K, which was under the control of the AOX1 promoter and α-mating factor signal sequence from Saccharomyces cerevisiae. The recombinant plasmid, designated as pPIC9K-PVADH, was linearized using SalI and transformed into P. pastoris GS115 by electroporation. The PVADH activity reached 55 U/mL in a shake flask and 902 U/mL in a 3-L bioreactor. Surprisingly, the sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis and N-terminal sequencing indicated that the secreted PVADH was truncated, and it had only 548 amino acid residues (an 81-amino acid sequence from the secreted protein was cleaved). The optimum pH and temperature ranges for the truncated PVADH were 7.0-8.0 and 41-53 °C, respectively. The activation energy of the recombinant truncated PVADH was approximately 10.36 kcal/mol between 29 and 41 °C. Both Ca(2+) and Mg(2+) had stimulating effects on the activity of PVADH. With PVA1799 as the substrate, the truncated PVADH had a Michaelis constant (K (m)) of 1.89 mg/mL and a maximum reaction rate (V (max)) of 34.9 nmol/(min mg protein). To the best of our knowledge, this is the first report on the expression of PVADH in P. pastoris, and the achieved PVADH yield is the highest ever reported.
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Affiliation(s)
- Dongxu Jia
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
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Expression and fermentation optimization of oxidized polyvinyl alcohol hydrolase in E. coli. ACTA ACUST UNITED AC 2012; 39:99-104. [DOI: 10.1007/s10295-011-1004-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Accepted: 06/08/2011] [Indexed: 10/18/2022]
Abstract
Abstract
Oxidized polyvinyl alcohol (PVA) hydrolase (OPH) is a key enzyme in the degradation of PVA, suggesting that OPH has a great potential for application in textile desizing processes. In this study, the OPH gene from Sphingopyxis sp. 113P3 was modified, by artificial synthesis, for overexpression in Escherichia coli. The OPH gene, lacking the sequence encoding the original signal peptide, was inserted into pET-20b (+) expression vector, which was then used to transform E. coli BL21 (DE3). OPH expression was detected in culture medium in which the transformed E. coli BL21 (DE3) was grown. Nutritional and environmental conditions were investigated for improved production of OPH protein by the recombinant strain. The highest OPH activity measured was 47.54 U/mL and was reached after 84 h under optimal fermentation conditions; this level is 2.64-fold higher that obtained under sub-optimal conditions. The productivity of recombinant OPH reached 565.95 U/L/h. The effect of glycine on the secretion of recombinant OPH was examined by adding glycine to the culture medium to a final concentration of 200 mM. This concentration of glycine reduced the fermentation time by 24 h and increased the productivity of recombinant OPH to 733.17 U/L/h. Our results suggest that the recombinant strain reported here has great potential for use in industrial applications.
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Amann M, Minge O. Biodegradability of Poly(vinyl acetate) and Related Polymers. SYNTHETIC BIODEGRADABLE POLYMERS 2011. [DOI: 10.1007/12_2011_153] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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Tang B, Liao X, Zhang D, Li M, Li R, Yan K, Du G, Chen J. Enhanced production of poly(vinyl alcohol)-degrading enzymes by mixed microbial culture using 1,4-butanediol and designed fermentation strategies. Polym Degrad Stab 2010. [DOI: 10.1016/j.polymdegradstab.2009.12.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Klankeo P, Nopcharoenkul W, Pinyakong O. Two novel pyrene-degrading Diaphorobacter sp. and Pseudoxanthomonas sp. isolated from soil. J Biosci Bioeng 2009; 108:488-95. [DOI: 10.1016/j.jbiosc.2009.05.016] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 05/19/2009] [Accepted: 05/25/2009] [Indexed: 01/30/2023]
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Biochemistry of microbial polyvinyl alcohol degradation. Appl Microbiol Biotechnol 2009; 84:227-37. [DOI: 10.1007/s00253-009-2113-6] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2009] [Revised: 06/23/2009] [Accepted: 06/23/2009] [Indexed: 11/25/2022]
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Molecular characteristics of xenobiotic-degrading sphingomonads. Appl Microbiol Biotechnol 2008; 81:793-811. [PMID: 19002456 DOI: 10.1007/s00253-008-1752-3] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 10/06/2008] [Accepted: 10/15/2008] [Indexed: 10/21/2022]
Abstract
The genus Sphingomonas (sensu latu) belongs to the alpha-Proteobacteria and comprises strictly aerobic chemoheterotrophic bacteria that are widespread in various aquatic and terrestrial environments. The members of this genus are often isolated and studied because of their ability to degrade recalcitrant natural and anthropogenic compounds, such as (substituted) biphenyl(s) and naphthalene(s), fluorene, (substituted) phenanthrene(s), pyrene, (chlorinated) diphenylether(s), (chlorinated) furan(s), (chlorinated) dibenzo-p-dioxin(s), carbazole, estradiol, polyethylene glycols, chlorinated phenols, nonylphenols, and different herbicides and pesticides. The metabolic versatility of these organisms suggests that they have evolved mechanisms to adapt quicker and/or more efficiently to the degradation of novel compounds in the environment than members of other bacterial genera. Comparative analyses demonstrate that sphingomonads generally use similar degradative pathways as other groups of microorganisms but deviate from competing microorganisms by the existence of multiple hydroxylating oxygenases and the conservation of specific gene clusters. Furthermore, there is increasing evidence for the existence of plasmids that only can be disseminated among sphingomonads and which undergo after conjugative transfer pronounced rearrangements.
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