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Bhattacharyya M, Dhar R, Basu S, Das A, Reynolds DM, Dutta TK. Molecular evaluation of the metabolism of estrogenic di(2-ethylhexyl) phthalate in Mycolicibacterium sp. Microb Cell Fact 2023; 22:82. [PMID: 37101185 PMCID: PMC10134610 DOI: 10.1186/s12934-023-02096-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 04/12/2023] [Indexed: 04/28/2023] Open
Abstract
BACKGROUND Di(2-ethylhexyl) phthalate (DEHP) is a widely detected plasticizer and a priority pollutant of utmost concern for its adverse impact on humans, wildlife and the environment. To eliminate such toxic burden, biological processes are the most promising ways to combat rampant environmental insults under eco-friendly conditions. The present study investigated the biochemical and molecular assessment of the catabolic potential of Mycolicibacterium sp. strain MBM in the assimilation of estrogenic DEHP. RESULTS A detailed biochemical study revealed an initial hydrolytic pathway of degradation for DEHP followed by the assimilation of hydrolyzed phthalic acid and 2-ethylhexanol to TCA cycle intermediates. Besides the inducible nature of DEHP-catabolic enzymes, strain MBM can efficiently utilize various low- and high-molecular-weight phthalate diesters and can grow under moderately halotolerant conditions. Whole genome sequence analysis exhibited a genome size of 6.2 Mb with a GC content of 66.51% containing 6,878 coding sequences, including multiple genes, annotated as relevant to the catabolism of phthalic acid esters (PAEs). Substantiating the annotated genes through transcriptome assessment followed by RT-qPCR analysis, the possible roles of upregulated genes/gene clusters in the metabolism of DEHP were revealed, reinforcing the biochemical pathway of degradation at the molecular level. CONCLUSIONS A detailed co-relation of biochemical, genomic, transcriptomic and RT-qPCR analyses highlights the PAE-degrading catabolic machineries in strain MBM. Further, due to functional attributes in the salinity range of both freshwater and seawater, strain MBM may find use as a suitable candidate in the bioremediation of PAEs.
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Affiliation(s)
- Mousumi Bhattacharyya
- Department of Microbiology, Bose Institute, EN-80, Sector V, Salt Lake, Kolkata, West Bengal, 700091, India
| | - Rinita Dhar
- Department of Microbiology, Bose Institute, EN-80, Sector V, Salt Lake, Kolkata, West Bengal, 700091, India
| | - Suman Basu
- Department of Microbiology, Bose Institute, EN-80, Sector V, Salt Lake, Kolkata, West Bengal, 700091, India
| | - Avijit Das
- Department of Microbiology, Bose Institute, EN-80, Sector V, Salt Lake, Kolkata, West Bengal, 700091, India
| | - Darren M Reynolds
- Centre for Research in Biosciences, Department of Applied Sciences, University of the West of England, Bristol, BS16 1QY, UK
| | - Tapan K Dutta
- Department of Microbiology, Bose Institute, EN-80, Sector V, Salt Lake, Kolkata, West Bengal, 700091, India.
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Fructose-Based Production of Short-Chain-Length and Medium-Chain-Length Polyhydroxyalkanoate Copolymer by Arctic Pseudomonas sp. B14-6. Polymers (Basel) 2021; 13:polym13091398. [PMID: 33925903 PMCID: PMC8123457 DOI: 10.3390/polym13091398] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 04/19/2021] [Accepted: 04/22/2021] [Indexed: 02/06/2023] Open
Abstract
Arctic bacteria employ various mechanisms to survive harsh conditions, one of which is to accumulate carbon and energy inside the cell in the form of polyhydroxyalkanoate (PHA). Whole-genome sequencing of a new Arctic soil bacterium Pseudomonas sp. B14-6 revealed two PHA-production-related gene clusters containing four PHA synthase genes (phaC). Pseudomonas sp. B14-6 produced poly(6% 3-hydroxybutyrate-co-94% 3-hydroxyalkanoate) from various carbon sources, containing short-chain-length PHA (scl-PHA) and medium-chain-length PHA (mcl-PHA) composed of various monomers analyzed by GC-MS, such as 3-hydroxybutyrate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate, 3-hydroxydodecenoic acid, 3-hydroxydodecanoic acid, and 3-hydroxytetradecanoic acid. By optimizing the PHA production media, we achieved 34.6% PHA content using 5% fructose, and 23.7% PHA content using 5% fructose syrup. Differential scanning calorimetry of the scl-co-mcl PHA determined a glass transition temperature (Tg) of 15.3 °C, melting temperature of 112.8 °C, crystallization temperature of 86.8 °C, and 3.82% crystallinity. In addition, gel permeation chromatography revealed a number average molecular weight of 3.6 × 104, weight average molecular weight of 9.1 × 104, and polydispersity index value of 2.5. Overall, the novel Pseudomonas sp. B14-6 produced a polymer with high medium-chain-length content, low Tg, and low crystallinity, indicating its potential use in medical applications.
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Photoheterotrophic Assimilation of Valerate and Associated Polyhydroxyalkanoate Production by Rhodospirillum rubrum. Appl Environ Microbiol 2020; 86:AEM.00901-20. [PMID: 32651203 DOI: 10.1128/aem.00901-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/02/2020] [Indexed: 02/06/2023] Open
Abstract
Purple nonsulfur bacteria are increasingly recognized for industrial applications in bioplastics, pigment, and biomass production. In order to optimize the yield of future biotechnological processes, the assimilation of different carbon sources by Rhodospirillum rubrum has to be understood. As they are released from several fermentation processes, volatile fatty acids (VFAs) represent a promising carbon source in the development of circular industrial applications. To obtain an exhaustive characterization of the photoheterotrophic metabolism of R. rubrum in the presence of valerate, we combined phenotypic, proteomic, and genomic approaches. We obtained evidence that valerate is cleaved into acetyl coenzyme A (acetyl-CoA) and propionyl-CoA and depends on the presence of bicarbonate ions. Genomic and enzyme inhibition data showed that a functional methylmalonyl-CoA pathway is essential. Our proteomic data showed that the photoheterotrophic assimilation of valerate induces an intracellular redox stress which is accompanied by an increased abundance of phasins (the main proteins present in polyhydroxyalkanoate [PHA] granules). Finally, we observed a significant increase in the production of the copolymer P(HB-co-HV), accounting for a very high (>80%) percentage of HV monomer. Moreover, an increase in the PHA content was obtained when bicarbonate ions were progressively added to the medium. The experimental conditions used in this study suggest that the redox imbalance is responsible for PHA production. These findings also reinforce the idea that purple nonsulfur bacteria are suitable for PHA production through a strategy other than the well-known feast-and-famine process.IMPORTANCE The use and the littering of plastics represent major issues that humanity has to face. Polyhydroxyalkanoates (PHAs) are good candidates for the replacement of oil-based plastics, as they exhibit comparable physicochemical properties but are biobased and biodegradable. However, the current industrial production of PHAs is curbed by the production costs, which are mainly linked to the carbon source. Volatile fatty acids issued from the fermentation processes constitute interesting carbon sources, since they are inexpensive and readily available. Among them, valerate is gaining interest regarding the ability of many bacteria to produce a copolymer of PHAs. Here, we describe the photoheterotrophic assimilation of valerate by Rhodospirillum rubrum, a purple nonsulfur bacterium mainly known for its metabolic versatility. Using a knowledge-based optimization process, we present a new strategy for the improvement of PHA production, paving the way for the use of R. rubrum in industrial processes.
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Diverse metabolic pathways in the degradation of phenylalkanoic acids and their monohydroxylated derivatives in Cupriavidus sp. strain ST-14. Process Biochem 2018. [DOI: 10.1016/j.procbio.2018.08.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Elvir L, Duclot F, Wang Z, Kabbaj M. Epigenetic regulation of motivated behaviors by histone deacetylase inhibitors. Neurosci Biobehav Rev 2017; 105:305-317. [PMID: 29020607 DOI: 10.1016/j.neubiorev.2017.09.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 09/26/2017] [Accepted: 09/27/2017] [Indexed: 12/15/2022]
Abstract
Growing evidence has begun to elucidate the contribution of epigenetic mechanisms in the modulation and maintenance of gene expression and behavior. Histone acetylation is one such epigenetic mechanism, which has been shown to profoundly alter gene expression and behaviors. In this review, we begin with an overview of the major epigenetic mechanisms including histones acetylation. We next focus on recent evidence about the influence of environmental stimuli on various motivated behaviors through histone acetylation and highlight how histone deacetylase inhibitors can correct some of the pathologies linked to motivated behaviors including substance abuse, feeding and social attachments. Particularly, we emphasize that the effects of histone deacetylase inhibitors on motivated behaviors are time and context-dependent.
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Affiliation(s)
- Lindsay Elvir
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306-1270, USA; Program of Neuroscience, Florida State University, Tallahassee, FL 32306-1270, USA
| | - Florian Duclot
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306-1270, USA; Program of Neuroscience, Florida State University, Tallahassee, FL 32306-1270, USA
| | - Zuoxin Wang
- Department of Psychology, Florida State University, Tallahassee, FL 32306-1270, USA; Program of Neuroscience, Florida State University, Tallahassee, FL 32306-1270, USA
| | - Mohamed Kabbaj
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306-1270, USA; Program of Neuroscience, Florida State University, Tallahassee, FL 32306-1270, USA.
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Chanasit W, Hodgson B, Sudesh K, Umsakul K. Efficient production of polyhydroxyalkanoates (PHAs) from Pseudomonas mendocina PSU using a biodiesel liquid waste (BLW) as the sole carbon source. Biosci Biotechnol Biochem 2016; 80:1440-50. [DOI: 10.1080/09168451.2016.1158628] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Abstract
Conditions for the optimal production of polyhydroxyalkanoate (PHA) by Pseudomonas mendocina PSU using a biodiesel liquid waste (BLW) were determined by response surface methodology. These were an initial carbon to nitrogen ratio (C/N) of 40 (mole/mole), an initial pH of 7.0, and a temperature of 35 °C. A biomass and PHA concentration of 3.65 g/L and about 2.6 g/L (77% DCW), respectively, were achieved in a growth associated process using 20 g/L glycerol in the BLW after 36 h of exponential growth. The PHA monomer compositions were 3HB (3-hydroxybutyrate), a short-chain-length-PHA, and the medium-chain-length-PHA e.g. 3-hydroxyoctanoate and 3-hydroxydecanoate. Both the phbC and phaC genes were characterized. The phbC enzyme had not been previously detected in a Pseudomonas mendocina species. A 2.15 g/L of an exopolysaccharide, alginate, was also produced with a similar composition to that of other Pseudomonas species.
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Affiliation(s)
- Wankuson Chanasit
- Faculty of Science, Department of Microbiology, Prince of Songkla University, Songkhla, Thailand
| | - Brian Hodgson
- Faculty of Pharmaceutical Sciences, Prince of Songkla University, Songkhla, Thailand
| | - Kumar Sudesh
- Ecobiomaterial Research Laboratory, School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia
| | - Kamontam Umsakul
- Faculty of Science, Department of Microbiology, Prince of Songkla University, Songkhla, Thailand
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Tajima K, Iwamoto K, Satoh Y, Sakai R, Satoh T, Dairi T. Advanced functionalization of polyhydroxyalkanoate via the UV-initiated thiol-ene click reaction. Appl Microbiol Biotechnol 2016; 100:4375-83. [PMID: 26743654 DOI: 10.1007/s00253-015-7252-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 12/12/2015] [Accepted: 12/14/2015] [Indexed: 10/22/2022]
Abstract
Polyhydroxyalkanoates (PHAs) incorporating vinyl-bearing 3-hydroxyalkanoates were prepared in 8.5-12.9 g L(-1) yield. The molar ratios (0-16 mol%) of the vinyl-bearing 3-hydroxyalkanoate derivatives were controlled by the continuous feeding of undecylenate at various concentrations. Subsequently, the PHAs were functionalized by UV-initiated thiol-ene click reaction and chemical modification. (1)H NMR spectra suggested that 3-mercaptopropionic acid and 2-aminoethanethiol were successfully introduced into the vinyl-bearing PHA. Subsequently, chemical modification using fluorescein or a fibronectin active fragment (GRGDS) was attempted. The former yielded a PHA derivative capable of emitting fluorescence under UV irradiation, which was useful for determining the miscibility of PHA in a composite film comprising poly-ʟ-lactic acid (PLLA) and PHA. In the latter case, PHA bearing GRGDS peptides exhibited cell adhesiveness, suggesting that its biocompatibility was improved upon peptide introduction. Taken together, the UV-initiated thiol-ene click reaction was demonstrated to be useful in PHA modification.
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Affiliation(s)
- Kenji Tajima
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo, 060-8628, Japan.
| | - Kosuke Iwamoto
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo, 060-8628, Japan
| | - Yasuharu Satoh
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo, 060-8628, Japan
| | - Ryosuke Sakai
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo, 060-8628, Japan.,Department of Materials Chemistry, Asahikawa National College of Technology, Asahikawa, 071-8142, Japan
| | - Toshifumi Satoh
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo, 060-8628, Japan
| | - Tohru Dairi
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo, 060-8628, Japan.
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Chen YJ, Huang YC, Lee CY. Production and characterization of medium-chain-length polyhydroxyalkanoates by Pseudomonas mosselii TO7. J Biosci Bioeng 2014; 118:145-52. [DOI: 10.1016/j.jbiosc.2014.01.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 01/24/2014] [Accepted: 01/27/2014] [Indexed: 11/25/2022]
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Abdel-Mawgoud AM, Lépine F, Déziel E. A stereospecific pathway diverts β-oxidation intermediates to the biosynthesis of rhamnolipid biosurfactants. ACTA ACUST UNITED AC 2013; 21:156-64. [PMID: 24374163 DOI: 10.1016/j.chembiol.2013.11.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 10/29/2013] [Accepted: 11/04/2013] [Indexed: 10/25/2022]
Abstract
Rhamnolipids are multipurpose surface-active molecules produced by the bacterium Pseudomonas aeruginosa from L-rhamnose and R-3-hydroxyalkanoate (C₁₀±₂) precursors. R-3-hydroxyalkanoate precursor is believed to be synthesized de novo. We demonstrate, however, that β-oxidation is the predominant source of this precursor. Inhibition of β-oxidation sharply decreases rhamnolipids production, even when using a nonfatty acid carbon source (glycerol). Isotope tracing shows that β-oxidation intermediates are direct precursors of rhamnolipids. A mutant-based survey revealed an operon coding for enoyl-CoA hydratases/isomerases (ECH/I), named RhlYZ, implicated in rhamnolipids production via an axial role in 3-hydroxyalkanoate synthesis. In vitro, RhlZ is an R-ECH/I transforming 2-decenoyl-CoA, a β-oxidation intermediate, into R-3-hydroxydecanoyl-CoA, the potential rhamnolipids precursor. Interestingly, polyhydroxyalkanoates share with rhamnolipids the RhlYZ-generated R-3-hydroxyalkanoates pool, as demonstrated by the decrease of polyhydroxyalkanoates upon mutation of rhlYZ and the increase of rhamnolipids in a polyhydroxyalkanoates-defective mutant.
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Affiliation(s)
| | | | - Eric Déziel
- INRS-Institut Armand-Frappier, Laval, QC H7V 1B7, Canada.
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Agnew DE, Pfleger BF. Synthetic biology strategies for synthesizing polyhydroxyalkanoates from unrelated carbon sources. Chem Eng Sci 2013; 103:58-67. [DOI: 10.1016/j.ces.2012.12.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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11
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Gutierrez M, Choi MH, Tian B, Xu J, Rho JK, Kim MO, Cho YH, Yoon SC. Simultaneous inhibition of rhamnolipid and polyhydroxyalkanoic acid synthesis and biofilm formation in Pseudomonas aeruginosa by 2-bromoalkanoic acids: effect of inhibitor alkyl-chain-length. PLoS One 2013; 8:e73986. [PMID: 24023921 PMCID: PMC3762805 DOI: 10.1371/journal.pone.0073986] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 07/25/2013] [Indexed: 11/19/2022] Open
Abstract
Pseudomonas aeruginosa, an opportunistic human pathogen is known to synthesize rhamnolipid and polyhydroxyalkanoic acid (PHA) of which the acyl-group precursors (e.g., (R)-3-hydroxydecanoic acid) are provided through RhlA and PhaG enzyme, respectively, which have 57% gene sequence homology. The inhibitory effect of three 2-bromo-fatty acids of 2-bromohexanoic acid (2-BrHA), 2-bromooctanoic acid (2-BrOA) and 2-bromodecanoic acid (2-BrDA) was compared to get an insight into the biochemical nature of their probable dual inhibition against the two enzymes. The 2-bromo-compounds were found to inhibit rhamnolipid and PHA synthesis simultaneously in alkyl-chain-length dependent manner at several millimolar concentrations. The separate and dual inhibition of the RhlA and PhaG pathway by the 2-bromo-compounds in the wild-type cells was verified by investigating their inhibitory effects on the rhamnolipid and PHA synthesis in P. aeruginosa ΔphaG and ΔrhlA mutants. Unexpectedly, the order of inhibition strength was found 2-BrHA (≥90% at 2 mM) > 2-BrOA > 2-BrDA, equally for all of the rhamnolipids and PHA synthesis, swarming motility and biofilm formation. We suggest that the novel strongest inhibitor 2-BrHA could be potentially exploited to control the rhamnolipid-associated group behaviors of this pathogen as well as for its utilization as a lead compound in screening for antimicrobial agents based on new antimicrobial targets.
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Affiliation(s)
- Merced Gutierrez
- Nano-Biomaterials Science Laboratory, Division of Applied Life Sciences, Graduate School, Gyeongsang National University, Jinju, Republic of Korea
- National Research Foundation Funded Pioneer Research Center for Alzheimer Disease Control, Gyeongsang National University, Jinju, Republic of Korea
| | - Mun Hwan Choi
- National Research Foundation Funded Pioneer Research Center for Alzheimer Disease Control, Gyeongsang National University, Jinju, Republic of Korea
| | - Baoxia Tian
- Nano-Biomaterials Science Laboratory, Division of Applied Life Sciences, Graduate School, Gyeongsang National University, Jinju, Republic of Korea
- National Research Foundation Funded Pioneer Research Center for Alzheimer Disease Control, Gyeongsang National University, Jinju, Republic of Korea
| | - Ju Xu
- Nano-Biomaterials Science Laboratory, Division of Applied Life Sciences, Graduate School, Gyeongsang National University, Jinju, Republic of Korea
| | - Jong Kook Rho
- Nano-Biomaterials Science Laboratory, Division of Applied Life Sciences, Graduate School, Gyeongsang National University, Jinju, Republic of Korea
| | - Myeong Ok Kim
- National Research Foundation Funded Pioneer Research Center for Alzheimer Disease Control, Gyeongsang National University, Jinju, Republic of Korea
- Neurobiology Laboratory, Division of Applied Life Sciences, Graduate School, Gyeongsang National University, Jinju, Republic of Korea
| | - You-Hee Cho
- Laboratory of Antiinfective Agents and Phage Therapy, College of Pharmacy, CHA University, Gyeonggi-do, Republic of Korea
| | - Sung Chul Yoon
- Nano-Biomaterials Science Laboratory, Division of Applied Life Sciences, Graduate School, Gyeongsang National University, Jinju, Republic of Korea
- National Research Foundation Funded Pioneer Research Center for Alzheimer Disease Control, Gyeongsang National University, Jinju, Republic of Korea
- * E-mail:
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Abstract
Long-chain-length hydrophobic acyl residues play a vital role in a multitude of essential biological structures and processes. They build the inner hydrophobic layers of biological membranes, are converted to intracellular storage compounds, and are used to modify protein properties or function as membrane anchors, to name only a few functions. Acyl thioesters are transferred by acyltransferases or transacylases to a variety of different substrates or are polymerized to lipophilic storage compounds. Lipases represent another important enzyme class dealing with fatty acyl chains; however, they cannot be regarded as acyltransferases in the strict sense. This review provides a detailed survey of the wide spectrum of bacterial acyltransferases and compares different enzyme families in regard to their catalytic mechanisms. On the basis of their studied or assumed mechanisms, most of the acyl-transferring enzymes can be divided into two groups. The majority of enzymes discussed in this review employ a conserved acyltransferase motif with an invariant histidine residue, followed by an acidic amino acid residue, and their catalytic mechanism is characterized by a noncovalent transition state. In contrast to that, lipases rely on completely different mechanism which employs a catalytic triad and functions via the formation of covalent intermediates. This is, for example, similar to the mechanism which has been suggested for polyester synthases. Consequently, although the presented enzyme types neither share homology nor have a common three-dimensional structure, and although they deal with greatly varying molecule structures, this variety is not reflected in their mechanisms, all of which rely on a catalytically active histidine residue.
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Affiliation(s)
- Annika Röttig
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität, Münster, Germany
| | - Alexander Steinbüchel
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität, Münster, Germany
- Environmental Sciences Department, King Abdulaziz University, Jeddah, Saudi Arabia
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Muhr A, Rechberger EM, Salerno A, Reiterer A, Malli K, Strohmeier K, Schober S, Mittelbach M, Koller M. Novel Description of mcl-PHA Biosynthesis by Pseudomonas chlororaphis from Animal-Derived Waste. J Biotechnol 2013; 165:45-51. [DOI: 10.1016/j.jbiotec.2013.02.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 02/04/2013] [Accepted: 02/06/2013] [Indexed: 10/27/2022]
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Sarkar J, Chowdhury PP, Dutta TK. Complete degradation of di-n-octyl phthalate by Gordonia sp. strain Dop5. CHEMOSPHERE 2013; 90:2571-2577. [PMID: 23211327 DOI: 10.1016/j.chemosphere.2012.10.101] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 10/26/2012] [Accepted: 10/29/2012] [Indexed: 06/01/2023]
Abstract
The present study describes the assimilation of di-n-octyl phthalate by an aerobic bacterium, isolated from municipal waste-contaminated soil sample utilizing di-n-octyl phthalate as the sole source of carbon and energy. The isolate was identified as Gordonia sp. based on the morphological, nutritional and biochemical characteristics as well as 16S rRNA gene sequence analysis. A combination of chromatographic and spectrometric analyses revealed a complete di-n-octyl assimilation pathway. In the degradation process, mono-n-octyl phthalate, phthalic acid, protocatechuic acid and 1-octanol were identified as the degradation products of di-n-octyl phthalate. Furthermore, phthalic acid was metabolized via protocatechuic acid involving protocatechuate 3,4-dioxygenase while 1-octanol was metabolized by NAD(+)-dependent dehydrogenases to 1-octanoic acid, which was subsequently degraded via β-oxidation, ultimately, leading to tricarboxylic acid cycle intermediates. Apart from phthalic acid and 1-octanol metabolizing pathway enzymes, two esterases, di-n-octyl phthalate hydrolase and mono-n-octyl phthalate hydrolase involved in di-n-octyl phthalate degradation were found to be inducible in nature. This is the first report on the metabolic pathway involved in the complete degradation of di-n-octyl phthalate by a single bacterial isolate, which is also capable of efficiently degrading other phthalate esters of environmental concern having either shorter or longer alkyl chains.
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Affiliation(s)
- Jayita Sarkar
- Department of Microbiology, Bose Institute, P-1/12, C.I.T. Scheme VII M, Kolkata, India
| | - Piyali Pal Chowdhury
- Department of Microbiology, Bose Institute, P-1/12, C.I.T. Scheme VII M, Kolkata, India
| | - Tapan K Dutta
- Department of Microbiology, Bose Institute, P-1/12, C.I.T. Scheme VII M, Kolkata, India.
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15
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Choi MH, Xu J, Gutierrez M, Yoo T, Cho YH, Yoon SC. Metabolic relationship between polyhydroxyalkanoic acid and rhamnolipid synthesis in Pseudomonas aeruginosa: Comparative 13C NMR analysis of the products in wild-type and mutants. J Biotechnol 2011; 151:30-42. [DOI: 10.1016/j.jbiotec.2010.10.072] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 09/16/2010] [Accepted: 10/19/2010] [Indexed: 11/28/2022]
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16
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Choi MH, Xu J, Rho JK, Zhao XP, Yoon SC. Enhanced production of longer side-chain polyhydroxyalkanoic acid with omega-aromatic group substitution in phaZ-disrupted Pseudomonas fluorescens BM07 mutant through unrelated carbon source cometabolism and salicylic acid beta-oxidation inhibition. BIORESOURCE TECHNOLOGY 2010; 101:4540-4548. [PMID: 20153638 DOI: 10.1016/j.biortech.2010.01.082] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 01/14/2010] [Accepted: 01/20/2010] [Indexed: 05/28/2023]
Abstract
The deletion of the intracellular polyhydroxyalkanoate (PHA) depolymerase gene (phaZ) in Pseudomonas fluorescens BM07 was found to increase more efficiently the levels of longer medium-chain-length (MCL) omega-aromatic monomer-units than in the wild-type strain when the cells were grown with a mixture of fructose and MCL omega-aromatic fatty acid in the presence of salicylic acid that is known as a beta-oxidation inhibitor in BM07 strain. When 11-phenoxyundecanoic acid was used as co-carbon source, the longest monomer-unit 3-hydroxy-11-phenoxyundecanoate, not reported in literature yet, was incorporated into the polymer chain up to approximately 10 mol%. An advantage of salicylic acid inhibition technique is that salicylic acid is not metabolized in BM07 strain, thus, the effective concentration of the inhibitor remaining constant throughout the cultivation. In conclusion, this new technique could be exploited for the enhanced production of side-chain modulated functional MCL-PHA with improved physicochemical properties in P. fluorescens BM07.
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Affiliation(s)
- Mun Hwan Choi
- Nano-Biomaterials Science Laboratory, Division of Applied Life Sciences (BK21), Graduate School and Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Republic of Korea
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Xu J, Zhao XP, Choi MH, Yoon SC. Isolation and characterization of a transposon mutant ofPseudomonas fluorescens BM07 enhancing the production of polyhydroxyalkanoic acid but deficient in cold-induced exobiopolymer production. FEMS Microbiol Lett 2010; 305:91-9. [DOI: 10.1111/j.1574-6968.2010.01903.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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FadD from Pseudomonas putida CA-3 is a true long-chain fatty acyl coenzyme A synthetase that activates phenylalkanoic and alkanoic acids. J Bacteriol 2009; 191:7554-65. [PMID: 19820085 DOI: 10.1128/jb.01016-09] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A fatty acyl coenzyme A synthetase (FadD) from Pseudomonas putida CA-3 is capable of activating a wide range of phenylalkanoic and alkanoic acids. It exhibits the highest rates of reaction and catalytic efficiency with long-chain aromatic and aliphatic substrates. FadD exhibits higher k(cat) and K(m) values for aromatic substrates than for the aliphatic equivalents (e.g., 15-phenylpentadecanoic acid versus pentadecanoic acid). FadD is inhibited noncompetitively by both acrylic acid and 2-bromooctanoic acid. The deletion of the fadD gene from P. putida CA-3 resulted in no detectable growth or polyhydroxyalkanoate (PHA) accumulation with 10-phenyldecanoic acid, decanoic acid, and longer-chain substrates. The results suggest that FadD is solely responsible for the activation of long-chain phenylalkanoic and alkanoic acids. While the CA-3DeltafadD mutant could grow on medium-chain substrates, a decrease in growth yield and PHA accumulation was observed. The PHA accumulated by CA-3DeltafadD contained a greater proportion of short-chain monomers than did wild-type PHA. Growth of CA-3DeltafadD was unaffected, but PHA accumulation decreased modestly with shorter-chain substrates. The complemented mutant regained 70% to 90% of the growth and PHA-accumulating ability of the wild-type strain depending on the substrate. The expression of an extra copy of fadD in P. putida CA-3 resulted in increased levels of PHA accumulation (up to 1.6-fold) and an increase in the incorporation of longer-monomer units into the PHA polymer.
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Choi MH, Xu J, Rho JK, Shim JH, Yoon SC. Shifting of the distribution of aromatic monomer-units in polyhydroxyalkanoic acid to longer units by salicylic acid in Pseudomonas fluorescens BM07 grown with mixtures of fructose and 11-phenoxyundecanoic acid. Biotechnol Bioeng 2009; 102:1209-21. [PMID: 18958860 DOI: 10.1002/bit.22149] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Medium-chain-length-polyhydroxyalkanoic acids (MCL-PHAs) formed in Pseudomonas spp. have a rather broad distribution of monomer-units whose precursors are supplied via beta-oxidation degradation of MCL fatty acids fed as the carbon source and/or via PhaG enzyme catalyzing the acyl-group transfer from 3-hydroxyacyl-ACPs derived from acetyl-CoA to coenzyme A. It was found that salicylic acid (SA), in a concentration dependent manner, suppressed the accumulation of PHA in Pseudomonas fluorescens BM07 from fructose as well as shifted the distribution of monomer-units derived from a MCL fatty acid co-added as carbon source (e.g., 11-phenoxyundecanoic acid (11-POU)) to longer monomer-units. Both SA and acrylic acid were found to induce high accumulations of 3-ketohexanoic acid in BM07 wild-type cells grown with n-hexanoic acid as well as to inhibit the formation of acetyl-CoA from acetoacetyl-CoA by BM07 cell extract, suggesting that 3-ketoacyl-CoA thiolase is their common beta-oxidation target. The structural motif of acrylic acid present in the molecular structure of SA may self-explain the similar actions of the two inhibitors. A comparison of monomer modulation between BM07 wild-type and DeltaphaG mutant cells grown on the mixtures of fructose and 11-POU revealed that both PhaG and beta-oxidation inhibitor may play a critical role in the synthesis of PHA with longer side-chain omega-functional substitutions.
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Affiliation(s)
- Mun Hwan Choi
- Nano-Biomaterials Science Laboratory, Division of Applied Life Sciences (BK21), Graduate School Gyeongsang National University, Jinju 660-701, South Korea
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Xu J, Choi MH, Natarajan S, Rho JK, Cho YH, Yoon SC. Effect of 2-bromooctanoic acid on the production of rhamnolipid and polyhydroxyalkanoic acid by Pseudomonas aeruginosa PA14 and PAO1. J Biotechnol 2008. [DOI: 10.1016/j.jbiotec.2008.07.1065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Enhanced biosorption of mercury(II) and cadmium(II) by cold-induced hydrophobic exobiopolymer secreted from the psychrotroph Pseudomonas fluorescens BM07. Appl Microbiol Biotechnol 2008; 80:531-44. [PMID: 18679675 DOI: 10.1007/s00253-008-1621-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2007] [Revised: 07/12/2008] [Accepted: 07/14/2008] [Indexed: 10/21/2022]
Abstract
The cells of psychrotrophic Pseudomonas fluorescens BM07 were found to secrete large amounts of exobiopolymer (EBP) composed of mainly hydrophobic (water insoluble) polypeptide(s) (as contain approximately 50 mol% hydrophobic amino acids, lacking cysteine residue) when grown on fructose containing limited M1 medium at the temperatures as low as 0-10 degrees C but trace amount at high (30 degrees C, optimum growth) temperature. Two types of nonliving BM07 cells (i.e., cells grown at 30 degrees C and 10 degrees C) as well as the freeze-dried EBP were compared for biosorption of mercury (Hg(II)) and cadmium (Cd(II)). The optimum adsorption pH was found 7 for Hg(II) but 6 for Cd(II), irrespective of the type of biomass. Equilibrium adsorption data well fitted the Langmuir adsorption model. The maximum adsorption (Q(max)) was 72.3, 97.4, and 286.2 mg Hg(II)/g dry biomass and 18.9, 27.0, and 61.5 mg Cd(II)/g dry biomass for cells grown at 30 degrees C and 10 degrees C and EBP, respectively, indicating major contribution of heavy metal adsorption by cold-induced EBP. Mercury(II) binding induced a significant shift of infrared (IR) amide I and II absorption of EBP whereas cadmium(II) binding showed only a very little shift. These IR shifts demonstrate that mercury(II) and cadmium(II) might have different binding sites in EBP, which was supported by X-ray diffraction and differential scanning calorimetric analysis and sorption results of chemically modified biomasses. This study implies that the psychrotrophs like BM07 strain may play an important role in the bioremediation of heavy metals in the temperate regions especially in the inactive cold season.
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Rojas-Rosas O, Villafaña-Rojas J, López-Dellamary FA, Nungaray-Arellano J, González-Reynoso O. Production and characterization of polyhydroxyalkanoates in Pseudomonas aeruginosa ATCC 9027 from glucose, an unrelated carbon source. Can J Microbiol 2008; 53:840-51. [PMID: 17898839 DOI: 10.1139/w07-023] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The production and characterization of polyhydroxyalkanoic acids (PHAs) from glucose in Pseudomonas aeruginosa ATCC 9027 is described. We determined that the synthesis of PHAs was not due to a complete lack of nitrogen source, as previously reported for other microorganisms. The synthesis of PHAs was observed during exponential growth and it depended on the carbon/nitrogen ratio in the culture. More significantly, the specific PHA accumulation rate in this phase was higher than that observed in the storage phase. This phenomenon was a consequence of higher extracellular production rates of gluconate and 2-ketogluconate detected during the storage phase. Therefore, the production of those acids decreased the synthesis of PHAs in P. aeruginosa. The maximum percentage of PHA accumulation obtained was 10.8% of the cell dry matter when all the glucose was consumed. The monomer composition of this PHA consisted only of saturated 3-hydroxy fatty acids (octanoic, decanoic, and dodecanoic acids) as shown by gas chromatography - mass spectroscopy and nuclear magnetic resonance analyses, where 3-hydroxydecanoic acid was the main component because of the high affinity of its PhaC synthase for this monomer. The physical properties of this PHA were determined by differential scanning calorimetry and gel permeation chromatography.
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Affiliation(s)
- Oscar Rojas-Rosas
- Department of Chemical Engineering, CUCEI, University of Guadalajara, Boulevard Marcelino Garcia-Barragan # 1451, Guadalajara, Jalisco 44430, Mexico
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Chatterjee S, Dutta TK. Complete degradation of butyl benzyl phthalate by a defined bacterial consortium: role of individual isolates in the assimilation pathway. CHEMOSPHERE 2008; 70:933-41. [PMID: 17669462 DOI: 10.1016/j.chemosphere.2007.06.058] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Revised: 06/22/2007] [Accepted: 06/24/2007] [Indexed: 05/16/2023]
Abstract
Two bacterial strains, in consortium, were isolated by enrichment techniques from municipal waste-contaminated soil, which utilized butyl benzyl phthalate (BBP) as the sole carbon source. One of the isolates was identified as Arthrobacter sp. strain WY and the other one as Acinetobacter sp. strain FW based on the morphological, nutritional and biochemical characteristics and 16S rRNA sequence analysis. Various metabolites of BBP engendered by Arthrobacter sp. strain WY were isolated and identified by a combination of chromatographic and spectrophotometric analyses, which revealed a pathway involving monobutylphthalate (MBuP), monobenzyl phthalate (MBzP), phthalic acid and protocatechuic acid. The protocatechuic acid in turn was processed by ortho-cleavage dioxygenase to form beta-carboxy-cis,cis-muconate, ultimately leading to the TCA cycle. The Arthrobacter sp. strain WY could not utilize the hydrolyzed alcohols of BBP. On the other hand, the Acinetobacter sp. strain FW, which by itself could not utilize BBP as the sole carbon source, is capable of utilizing the hydrolyzed alcohols of BBP. Benzyl alcohol was found to be metabolized by the Acinetobacter sp. strain FW via benzaldehyde, benzoic acid and catechol. Catechol was further degraded by ortho-cleavage dioxygenase to cis,cis-muconic acid and subsequently to muconolactone leading to beta-ketoadipate pathway. Moreover, the Acinetobacter sp. strain FW metabolized 1-butanol through butyraldehyde and butyric acid leading to the tricarboxylic acid cycle via beta-oxidation pathway. This is the first report on the complete degradation of BBP by a defined consortium describing the role of its individual constituents in the BBP assimilation pathway.
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Affiliation(s)
- Subhankar Chatterjee
- Department of Microbiology, Bose Institute, P-1/12 C.I.T. Scheme VII M, Kolkata 700 054, India
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The production of a cold-induced extracellular biopolymer by Pseudomonas fluorescens BM07 under various growth conditions and its role in heavy metals absorption. Process Biochem 2007. [DOI: 10.1016/j.procbio.2007.02.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Tobin KM, O'Connor KE. Polyhydroxyalkanoate accumulating diversity of Pseudomonas species utilising aromatic hydrocarbons. FEMS Microbiol Lett 2006; 253:111-8. [PMID: 16260095 DOI: 10.1016/j.femsle.2005.09.025] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Revised: 09/14/2005] [Accepted: 09/17/2005] [Indexed: 11/27/2022] Open
Abstract
A number of Pseudomonas strains accumulated polyhdroxyalkanoate (PHA) from a variety of aromatic hydrocarbons. In many strains the level of PHA accumulation was dependent on the side chain length of the phenylalkanoic acid provided for growth. 4 of the 8 strains accumulated increased levels of PHA as the side chain length of the phenylalkanoic acid substrate increased. PHA accumulated from styrene and phenylacetic acid was composed of aliphatic monomers only. The PHA accumulated from any one of the phenylalkanoic acids with 5 carbons or more in their side chain (n>or=5) was almost identical for all strains with PHA composed of both aromatic and aliphatic monomers. The predominant monomers accumulated were 3-hydroxyphenylvaleric acid and 3-hydroxyphenylhexanoic acid. The addition of the metabolic pathway inhibitors acrylic acid and 2-bromoctanoic acid resulted in decreased levels of PHA from phenylacetic acid, suggesting a role for both beta-oxidation and fatty acid synthesis in PHA accumulation from phenylacetic acid.
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Affiliation(s)
- Karen M Tobin
- Department of Industrial Microbiology, Centre for Synthesis and Chemical Biology, Conway Institute for Biomolecular and Biomedical Research, National University of Ireland, University College Dublin, Belfield, Dublin 4, Republic of Ireland
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Chatterjee S, Mallick S, Dutta TK. Pathways in the Degradation of Hydrolyzed Alcohols of Butyl Benzyl Phthalate in Metabolically Diverse Gordonia sp.Strain MTCC 4818. J Mol Microbiol Biotechnol 2005; 9:110-20. [PMID: 16319500 DOI: 10.1159/000088841] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In the present study, the metabolic pathways involved in the degradation of benzyl alcohol and 1-butanol, the hydrolyzed products of butyl benzyl phthalate, were investigated by the Gordonia sp. strain MTCC 4818. The strain can utilize both benzyl alcohol and 1-butanol individually as sole carbon sources, where benzyl alcohol was found to be metabolized via benzaldehyde, benzoic acid and catechol, which was further degraded by ortho-cleavage dioxygenase to cis,cis-muconic acid and subsequently to muconolactone leading to tricarboxylic acid cycle. On the other hand, 1-butanol was metabolized via butyraldehyde and butyric acid, which was channeled into the tricarboxylic acid cycle via the beta-oxidation pathway. Numbers of dehydrogenases, both NAD+-dependent and NAD+-independent, were found to be involved in the degradation of benzyl alcohol and 1-butanol, where several dehydrogenases exhibited relaxed substrate specificity. Both 2,3- and 3,4-dihydroxybenzoic acids were utilized by the test organism for growth and metabolized by the ortho-cleavage pathway by the cell-free extract of benzoate-grown cells, similar to catechol, suggesting possible broad substrate specificity of the ring cleavage dioxygenase. Moreover, the test organism can utilize various primary and secondary alcohols, aliphatic aldehydes and acids in the C2-C5 range besides n-hexadecane, 1,4-butanediol and cyclohexanol individually as the sole carbon sources indicating metabolic diversity in the Gordonia sp. strain MTCC 4818.
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Fernández D, Rodríguez E, Bassas M, Viñas M, Solanas A, Llorens J, Marqués A, Manresa A. Agro-industrial oily wastes as substrates for PHA production by the new strain Pseudomonas aeruginosa NCIB 40045: Effect of culture conditions. Biochem Eng J 2005. [DOI: 10.1016/j.bej.2005.04.022] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Ward PG, de Roo G, O'Connor KE. Accumulation of polyhydroxyalkanoate from styrene and phenylacetic acid by Pseudomonas putida CA-3. Appl Environ Microbiol 2005; 71:2046-52. [PMID: 15812037 PMCID: PMC1082534 DOI: 10.1128/aem.71.4.2046-2052.2005] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas putida CA-3 is capable of converting the aromatic hydrocarbon styrene, its metabolite phenylacetic acid, and glucose into polyhydroxyalkanoate (PHA) when a limiting concentration of nitrogen (as sodium ammonium phosphate) is supplied to the growth medium. PHA accumulation occurs to a low level when the nitrogen concentration drops below 26.8 mg/liter and increases rapidly once the nitrogen is no longer detectable in the growth medium. The depletion of nitrogen and the onset of PHA accumulation coincided with a decrease in the rate of substrate utilization and biochemical activity of whole cells grown on styrene, phenylacetic acid, and glucose. However, the efficiency of carbon conversion to PHA dramatically increased once the nitrogen concentration dropped below 26.8 mg/liter in the growth medium. When supplied with 67 mg of nitrogen/liter, the carbon-to-nitrogen (C:N) ratios that result in a maximum yield of PHA (grams of PHA per gram of carbon) for styrene, phenylacetic acid, and glucose are 28:1, 21:1, and 18:1, respectively. In cells grown on styrene and phenylacetic acid, decreasing the carbon-to-nitrogen ratio below 28:1 and 21:1, respectively, by increasing the nitrogen concentration and using a fixed carbon concentration leads to lower levels of PHA per cell and lower levels of PHA per batch of cells. Increasing the carbon-to-nitrogen ratio above 28:1 and 21:1 for cells grown on styrene and phenylacetic acid, respectively, by decreasing the nitrogen concentration and using a fixed carbon concentration increases the level of PHA per cell but results in a lower level of PHA per batch of cells. Increasing the carbon and nitrogen concentrations but maintaining the carbon-to-nitrogen ratio of 28:1 and 21:1 for cells grown on styrene and phenylacetic acid, respectively, results in an increase in the total PHA per batch of cells. The maximum yields for PHA from styrene, phenylacetic acid, and glucose are 0.11, 0.17, and 0.22 g of PHA per g of carbon, respectively.
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Affiliation(s)
- Patrick G Ward
- Department of Industrial Microbiology, Centre for Synthesis and Chemical Biology, Conway Institute for Biomolecular and Biomedical Research, National University of Ireland, University College Dublin, Belfield, Dublin 4, Republic of Ireland
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Ward PG, O'Connor KE. Bacterial synthesis of polyhydroxyalkanoates containing aromatic and aliphatic monomers by Pseudomonas putida CA-3. Int J Biol Macromol 2005; 35:127-33. [PMID: 15811466 DOI: 10.1016/j.ijbiomac.2005.01.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2004] [Revised: 01/07/2005] [Accepted: 01/07/2005] [Indexed: 10/25/2022]
Abstract
Pseudomonas putida CA-3 has the ability to accumulate to high levels unique polyhydroxyalkanoate (PHA) heteropolymers composed of aromatic and aliphatic monomers. The majority of monomers are aromatic making up 98% of the polymer. (R)-3-hydroxyphenylvalerate and (R)-3-hydroxyphenylhexanoate are the most abundant monomers found in polymers accumulated from phenylalkanoic acids with an uneven and even number of carbons on the acyl side chain respectively. PHAs accumulated from phenylvaleric and phenylhexanoic acid were partially crystalline while all other PHAs were amorphous. Significant differences in the yield and PHA content of the cells occurred when different phenylalkanoic acids were supplied as growth substrates. Increasing the initial concentration of the growth substrate increased both the PHA content of the cells and the overall yield (g PHA/g carbon supplied) of PHA accumulated by P. putida CA-3 cells. The highest PHA content (% cell dry wt.) from an aromatic carbon source was 59% when 15mM phenylvaleric acid was supplied as the sole source of carbon and energy. This corresponded to a maximum PHA yield of 0.42 g PHA/g carbon supplied. In and attempt to increase the level of PHA accumulated from related growth substrates acrylic acid was added to the growth medium. However, the addition of various concentrations of acrylic acid to the growth medium had either no effect or decreased the PHA content of the cell accumulated from phenylalkanoic acids by P. putida CA-3.
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Affiliation(s)
- Patrick G Ward
- Department of Industrial Microbiology, Centre for Synthesis and Chemical Biology, Conway Institute for Biomolecular and Biomedical Research, National University of Ireland, University College Dublin, Belfield, Dublin 4, Ireland
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Xu J, Guo B, Zhang Z, Wu Q, Zhou Q, Chen J, Chen G, Li G. A mathematical model for regulating monomer composition of the microbially synthesized polyhydroxyalkanoate copolymers. Biotechnol Bioeng 2005; 90:821-9. [PMID: 15858793 DOI: 10.1002/bit.20487] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A mathematical model is proposed for predicting the copolymer composition of the microbially synthesized polyhydroxyalkanoate (PHA) copolymers. Based on the biochemical reactions involved in the precursor formation and polymerization pathways, the model correlates the copolymer composition with the cultivation conditions, the enzyme levels and selectivity, and the metabolic pathways. It suggests the following points: (1) in the case of a sole carbon source, the copolymer composition depends mainly on the topology of the metabolic pathways and the selectivity of both the enzymes involved in the precursor formation and the polymerization route; (2) the copolymer composition can be varied in a wide range via alteration of the flux ratio of different types of monomers channeled from two or more independent and simultaneous pathways; (3) the enzymes which should be over-expressed or inhibited to obtain the desired copolymer composition can be predicted. For example, inhibition of the beta-oxidation pathway will increase the content of the monomer units with longer chain length. To test the model, various experiments were envisaged by varying cultivation time, concentration and chain length of the sole carbon source, and molar ratio of the cosubstrates. The predictions from the model agree well with the experimental results. Therefore, the proposed model will be useful in predicting the PHA copolymer composition under different biochemical reaction conditions. In other words, it can provide a guide for the synthesis of desired PHA copolymers.
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Affiliation(s)
- Jun Xu
- Institute of Polymer Science and Engineering, Department of Chemical Engineering, School of Material Science and Engineering, Tsinghua University, Beijing 100084, China
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Richard A, Margaritis A. Empirical modeling of batch fermentation kinetics for poly(glutamic acid) production and other microbial biopolymers. Biotechnol Bioeng 2004; 87:501-15. [PMID: 15286988 DOI: 10.1002/bit.20156] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
An empirical kinetic model is proposed for the batch production of poly(glutamic acid) from Bacillus subtilis IFO 3335. In addition, the proposed model was used to fit the kinetic data of poly(glutamic acid) production from other bacterial strains using different media, as well as kinetic data from different strains for the production of the exocellular biopolymers dextran, hyaluronic acid, xanthan, alginate, and the endocellular biopolymer polyhydroxybutyrate. The empirical model treats the biopolymer as a component of the biomass and fits the experimental biomass data using a sigmoidal relationship that includes the maximum specific growth rate, mu(max), and the substrate saturation parameter, K(S). An empirical parameter, the relative coefficient (r), quantifies, in relative terms, the degree of nongrowth-associated biopolymer formation.
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Affiliation(s)
- Andrew Richard
- Department of Chemical and Biochemical Engineering, The University of Western Ontario, London, Ontario, Canada, N6A 5B9
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