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Bertelmann C, Mock M, Schmid A, Bühler B. Efficiency aspects of regioselective testosterone hydroxylation with highly active CYP450-based whole-cell biocatalysts. Microb Biotechnol 2024; 17:e14378. [PMID: 38018939 PMCID: PMC10832557 DOI: 10.1111/1751-7915.14378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 11/12/2023] [Indexed: 11/30/2023] Open
Abstract
Steroid hydroxylations belong to the industrially most relevant reactions catalysed by cytochrome P450 monooxygenases (CYP450s) due to the pharmacological relevance of hydroxylated derivatives. The implementation of respective bioprocesses at an industrial scale still suffers from several limitations commonly found in CYP450 catalysis, that is low turnover rates, enzyme instability, inhibition and toxicity related to the substrate(s) and/or product(s). Recently, we achieved a new level of steroid hydroxylation rates by introducing highly active testosterone-hydroxylating CYP450 BM3 variants together with the hydrophobic outer membrane protein AlkL into Escherichia coli-based whole-cell biocatalysts. However, the activity tended to decrease, which possibly impedes overall productivities and final product titres. In this study, a considerable instability was confirmed and subject to a systematic investigation regarding possible causes. In-depth evaluation of whole-cell biocatalyst kinetics and stability revealed a limitation in substrate availability due to poor testosterone solubility as well as inhibition by the main product 15β-hydroxytestosterone. Instability of CYP450 BM3 variants was disclosed as another critical factor, which is of general significance for CYP450-based biocatalysis. Presented results reveal biocatalyst, reaction and process engineering strategies auguring well for industrial implementation of the developed steroid hydroxylation platform.
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Affiliation(s)
| | - Magdalena Mock
- Department of Solar MaterialsLeipzigGermany
- Present address:
Department of Mechanical Engineering and Material SciencesGeorg Agricola University of Applied SciencesBochumGermany
| | | | - Bruno Bühler
- Department of Solar MaterialsLeipzigGermany
- Department of Microbial BiotechnologyHelmholtz Centre for Environmental Research GmbH–UFZLeipzigGermany
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2
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Fan J, Zhang Y, Wu P, Zhang X, Bai Y. Enhancing cofactor regeneration of cyanobacteria for the light-powered synthesis of chiral alcohols. Bioorg Chem 2021; 118:105477. [PMID: 34814084 DOI: 10.1016/j.bioorg.2021.105477] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 12/12/2022]
Abstract
Cyanobacteria Synechocystis sp. PCC 6803 was exploited as green cell factory for light-powered asymmetric synthesis of aromatic chiral alcohols. The effect of temperature, light, substrate and cell concentration on substrate conversions were investigated. Under the optimal condition, a series of chiral alcohols were synthesized with conversions up to 95% and enantiomer excess (ee) > 99%. We found that the addition of Na2S2O3 and Angeli's Salt increased the NADPH content by 20% and 25%, respectively. As a result, the time to reach 95% substrate conversion was shortened by 12 h, which demonstrated that the NADPH regeneration and hence the reaction rates can be regulated in cyanobacteria. This blue-green algae based biocatalysis showed its potential for chiral compounds production in future.
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Affiliation(s)
- Jianhua Fan
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China; Department of Applied Biology, East China University of Science and Technology, Shanghai 200237, PR China
| | - Yinghui Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China; Department of Applied Biology, East China University of Science and Technology, Shanghai 200237, PR China
| | - Ping Wu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China; Department of Applied Biology, East China University of Science and Technology, Shanghai 200237, PR China
| | - Xiaoyan Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China; Department of Bioengineering, East China University of Science and Technology, Shanghai 200237, PR China
| | - Yunpeng Bai
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China; Department of Bioengineering, East China University of Science and Technology, Shanghai 200237, PR China.
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3
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Jodlbauer J, Rohr T, Spadiut O, Mihovilovic MD, Rudroff F. Biocatalysis in Green and Blue: Cyanobacteria. Trends Biotechnol 2021; 39:875-889. [PMID: 33468423 DOI: 10.1016/j.tibtech.2020.12.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 12/14/2020] [Accepted: 12/15/2020] [Indexed: 12/17/2022]
Abstract
Recently, several studies have proven the potential of cyanobacteria as whole-cell biocatalysts for biotransformation. Compared to heterotrophic hosts, cyanobacteria show unique advantages thanks to their photoautotrophic metabolism. Their ability to use light as energy and CO2 as carbon source promises a truly sustainable production platform. Their photoautotrophic metabolism offers an encouraging source of reducing power, which makes them attractive for redox-based biotechnological purposes. To exploit the full potential of these whole-cell biocatalysts, cyanobacterial cells must be considered in their entirety. With this emphasis, this review summarizes the latest developments in cyanobacteria research with a strong focus on the benefits associated with their unique metabolism. Remaining bottlenecks and recent strategies to overcome them are evaluated for their potential in future applications.
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Affiliation(s)
- Julia Jodlbauer
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/OC-163, 1060 Vienna, Austria
| | - Thomas Rohr
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/OC-163, 1060 Vienna, Austria
| | - Oliver Spadiut
- Institute of Chemical Engineering, research area Biochemical Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060 Vienna, Austria
| | - Marko D Mihovilovic
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/OC-163, 1060 Vienna, Austria
| | - Florian Rudroff
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/OC-163, 1060 Vienna, Austria.
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4
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Kutyła M, Fiedurek J, Gromada A, Jędrzejewski K, Trytek M. Mutagenesis and Adaptation of the Psychrotrophic Fungus Chrysosporium pannorum A-1 as a Method for Improving β-pinene Bioconversion. Molecules 2020; 25:E2589. [PMID: 32498456 PMCID: PMC7321369 DOI: 10.3390/molecules25112589] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 05/31/2020] [Accepted: 06/01/2020] [Indexed: 11/17/2022] Open
Abstract
Mutagenesis and adaptation of the psychrotrophic fungus Chrysosporium pannorum A-1 to the toxic substrate β-pinene were used to obtain a biocatalyst with increased resistance to this terpene and improved bioconversion properties. Mutants of the parental strain were induced with UV light and N-methyl-N'-nitro-N-nitrosoguanidine. Mutants resistant to β-pinene were isolated using agar plates with a linear gradient of substrate concentrations. Active mutants were selected based on their general metabolic activity (GMA) expressed as oxygen consumption rate. Compared to the parental strain, the most active mutant showed an enhanced biotransformation ability to convert β-pinene to trans-pinocarveol (315 mg per g of dry mycelium), a 4.3-fold greater biocatalytic activity, and a higher resistance to H2O2-induced oxidative stress. Biotransformation using adapted mutants yielded twice as much trans-pinocarveol as the reaction catalyzed by non-adapted mutants. The results indicate that mutagenesis and adaptation of C. pannorum A-1 is an effective method of enhancing β-bioconversion of terpenes.
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Affiliation(s)
| | | | | | | | - Mariusz Trytek
- Department of Industrial and Environmental Microbiology, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland; (M.K.); (J.F.); (A.G.); (K.J.)
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5
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Volmer J, Lindmeyer M, Seipp J, Schmid A, Bühler B. Constitutively solvent‐tolerantPseudomonas taiwanensisVLB120∆C∆ttgVsupports particularly high‐styrene epoxidation activities when grown under glucose excess conditions. Biotechnol Bioeng 2019; 116:1089-1101. [DOI: 10.1002/bit.26924] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 12/17/2018] [Accepted: 01/06/2019] [Indexed: 01/08/2023]
Affiliation(s)
- Jan Volmer
- Department of Biochemical and Chemical EngineeringTU Dortmund UniversityDortmund Germany
| | - Martin Lindmeyer
- Department of Biochemical and Chemical EngineeringTU Dortmund UniversityDortmund Germany
- Department of Solar MaterialsHelmholtz Centre for Environmental Research GmbH–UFZLeipzig Germany
| | - Julia Seipp
- Department of Biochemical and Chemical EngineeringTU Dortmund UniversityDortmund Germany
| | - Andreas Schmid
- Department of Solar MaterialsHelmholtz Centre for Environmental Research GmbH–UFZLeipzig Germany
| | - Bruno Bühler
- Department of Solar MaterialsHelmholtz Centre for Environmental Research GmbH–UFZLeipzig Germany
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6
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Screening of organic solvents for bioprocesses using aqueous-organic two-phase systems. Biotechnol Adv 2018; 36:1801-1814. [DOI: 10.1016/j.biotechadv.2018.05.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 05/04/2018] [Accepted: 05/29/2018] [Indexed: 01/10/2023]
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7
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Fiedurek J, Trytek M, Szczodrak J. Strain improvement of industrially important microorganisms based on resistance to toxic metabolites and abiotic stress. J Basic Microbiol 2017; 57:445-459. [DOI: 10.1002/jobm.201600710] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/04/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Jan Fiedurek
- Department of Industrial Microbiology; Institute of Microbiology and Biotechnology; Maria Curie-Skłodowska University; Lublin Poland
| | - Mariusz Trytek
- Department of Industrial Microbiology; Institute of Microbiology and Biotechnology; Maria Curie-Skłodowska University; Lublin Poland
| | - Janusz Szczodrak
- Department of Industrial Microbiology; Institute of Microbiology and Biotechnology; Maria Curie-Skłodowska University; Lublin Poland
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Schmutzler K, Kupitz K, Schmid A, Buehler K. Hyperadherence of Pseudomonas taiwanensis VLB120ΔC increases productivity of (S)-styrene oxide formation. Microb Biotechnol 2016; 10:735-744. [PMID: 27411543 PMCID: PMC5481534 DOI: 10.1111/1751-7915.12378] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 06/14/2016] [Accepted: 06/15/2016] [Indexed: 01/11/2023] Open
Abstract
The attachment strength of biofilm microbes is responsible for the adherence of the cells to surfaces and thus is a critical parameter in biofilm processes. In tubular microreactors, aqueous‐air segmented flow ensures an optimal oxygen supply and prevents excessive biofilm growth. However, organisms growing in these systems depend on an adaptation phase of several days, before mature and strong biofilms can develop. This is due to strong interfacial forces. In this study, a hyperadherent mutant of Pseudomonas taiwanensis VLB120ΔCeGFP possessing an engineered cyclic diguanylate metabolism, was applied to a continuous biofilm process for the production of (S)‐styrene oxide. Cells of the mutant P. taiwanensis VLB120ΔCeGFP Δ04710, showing the same specific activity as the wild type, adhered substantially stronger to the substratum. Adaptation to the high interfacial forces was not necessary in these cases. Thereby, 40% higher final product concentrations were achieved and the maximal volumetric productivity of the parent strain was significantly surpassed by P. taiwanensis VLB120ΔCeGFP Δ04710. Applying mutants with strong adhesion in biofilm‐based catalysis opens the door to biological process control in future applications of catalytic biofilms using other industrially relevant strains.
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Affiliation(s)
- Karolin Schmutzler
- Laboratory of Chemical Biotechnology, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Strasse 66, 44227, Dortmund, Germany.,Department of Solar Materials, Helmholtz-Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318, Leipzig, Germany
| | - Katharina Kupitz
- Laboratory of Chemical Biotechnology, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Strasse 66, 44227, Dortmund, Germany
| | - Andreas Schmid
- Department of Solar Materials, Helmholtz-Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318, Leipzig, Germany
| | - Katja Buehler
- Department of Solar Materials, Helmholtz-Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318, Leipzig, Germany
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9
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Volmer J, Schmid A, Bühler B. Guiding bioprocess design by microbial ecology. Curr Opin Microbiol 2015; 25:25-32. [DOI: 10.1016/j.mib.2015.02.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/26/2015] [Accepted: 02/26/2015] [Indexed: 12/20/2022]
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10
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Guidelines for development and implementation of biocatalytic P450 processes. Appl Microbiol Biotechnol 2015; 99:2465-83. [PMID: 25652652 DOI: 10.1007/s00253-015-6403-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 01/09/2015] [Accepted: 01/12/2015] [Indexed: 01/17/2023]
Abstract
Biocatalytic reactions performed by cytochrome P450 monooxygenases are interesting in pharmaceutical research since they are involved in human drug metabolism. Furthermore, they are potentially interesting as biocatalysts for synthetic chemistry because of the exquisite selectivity of the chemistry they undertake. For example, selective hydroxylation can be undertaken on a highly functionalized molecule without the need for functional group protection. Recent progress in the discovery of novel P450s as well as protein engineering of these enzymes strongly encourages further development of their application, including use in synthetic processes. The biological characteristics of P450s (e.g., cofactor dependence) motivate the use of whole-cell systems for synthetic processes, and those processes implemented in industry are so far dominated by growing cells and native host systems. However, for an economically feasible process, the expression of P450 systems in a heterologous host with sufficient biocatalyst yield (g/g cdw) for non-growing systems or space-time yield (g/L/h) for growing systems remains a major challenge. This review summarizes the opportunities to improve P450 whole-cell processes and strategies in order to apply and implement them in industrial processes, both from a biological and process perspective. Indeed, a combined approach of host selection and cell engineering, integrated with process engineering, is suggested as the most effective route to implementation.
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11
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Engineering of Pseudomonas taiwanensis VLB120 for constitutive solvent tolerance and increased specific styrene epoxidation activity. Appl Environ Microbiol 2014; 80:6539-48. [PMID: 25128338 DOI: 10.1128/aem.01940-14] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The application of whole cells as biocatalysts is often limited by the toxicity of organic solvents, which constitute interesting substrates/products or can be used as a second phase for in situ product removal and as tools to control multistep biocatalysis. Solvent-tolerant bacteria, especially Pseudomonas strains, are proposed as promising hosts to overcome such limitations due to their inherent solvent tolerance mechanisms. However, potential industrial applications suffer from tedious, unproductive adaptation processes, phenotypic variability, and instable solvent-tolerant phenotypes. In this study, genes described to be involved in solvent tolerance were identified in Pseudomonas taiwanensis VLB120, and adaptive solvent tolerance was proven by cultivation in the presence of 1% (vol/vol) toluene. Deletion of ttgV, coding for the specific transcriptional repressor of solvent efflux pump TtgGHI gene expression, led to constitutively solvent-tolerant mutants of P. taiwanensis VLB120 and VLB120ΔC. Interestingly, the increased amount of solvent efflux pumps enhanced not only growth in the presence of toluene and styrene but also the biocatalytic performance in terms of stereospecific styrene epoxidation, although proton-driven solvent efflux is expected to compete with the styrene monooxygenase for metabolic energy. Compared to that of the P. taiwanensis VLB120ΔC parent strain, the maximum specific epoxidation activity of P. taiwanensis VLB120ΔCΔttgV doubled to 67 U/g of cells (dry weight). This study shows that solvent tolerance mechanisms, e.g., the solvent efflux pump TtgGHI, not only allow for growth in the presence of organic compounds but can also be used as tools to improve redox biocatalysis involving organic solvents.
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12
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Schrewe M, Julsing MK, Bühler B, Schmid A. Whole-cell biocatalysis for selective and productive C-O functional group introduction and modification. Chem Soc Rev 2014; 42:6346-77. [PMID: 23475180 DOI: 10.1039/c3cs60011d] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
During the last decades, biocatalysis became of increasing importance for chemical and pharmaceutical industries. Regarding regio- and stereospecificity, enzymes have shown to be superior compared to traditional chemical synthesis approaches, especially in C-O functional group chemistry. Catalysts established on a process level are diverse and can be classified along a functional continuum starting with single-step biotransformations using isolated enzymes or microbial strains towards fermentative processes with recombinant microorganisms containing artificial synthetic pathways. The complex organization of respective enzymes combined with aspects such as cofactor dependency and low stability in isolated form often favors the use of whole cells over that of isolated enzymes. Based on an inventory of the large spectrum of biocatalytic C-O functional group chemistry, this review focuses on highlighting the potentials, limitations, and solutions offered by the application of self-regenerating microbial cells as biocatalysts. Different cellular functionalities are discussed in the light of their (possible) contribution to catalyst efficiency. The combined achievements in the areas of protein, genetic, metabolic, and reaction engineering enable the development of whole-cell biocatalysts as powerful tools in organic synthesis.
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Affiliation(s)
- Manfred Schrewe
- Laboratory of Chemical Biotechnology, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Strasse 66, 44227 Dortmund, Germany
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13
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Scheps D, Honda Malca S, Richter SM, Marisch K, Nestl BM, Hauer B. Synthesis of ω-hydroxy dodecanoic acid based on an engineered CYP153A fusion construct. Microb Biotechnol 2013; 6:694-707. [PMID: 23941649 PMCID: PMC3815936 DOI: 10.1111/1751-7915.12073] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 06/07/2013] [Accepted: 06/08/2013] [Indexed: 01/09/2023] Open
Abstract
A bacterial P450 monooxygenase-based whole cell biocatalyst using Escherichia coli has been applied in the production of ω-hydroxy dodecanoic acid from dodecanoic acid (C12-FA) or the corresponding methyl ester. We have constructed and purified a chimeric protein where the fusion of the monooxygenase CYP153A from Marinobacter aquaeloei to the reductase domain of P450 BM3 from Bacillus megaterium ensures optimal protein expression and efficient electron coupling. The chimera was demonstrated to be functional and three times more efficient than other sets of redox components evaluated. The established fusion protein (CYP153AM. aq.-CPR) was used for the hydroxylation of C12-FA in in vivo studies. These experiments yielded 1.2 g l–1 ω-hydroxy dodecanoic from 10 g l–1 C12-FA with high regioselectivity (> 95%) for the terminal position. As a second strategy, we utilized C12-FA methyl ester as substrate in a two-phase system (5:1 aqueous/organic phase) configuration to overcome low substrate solubility and product toxicity by continuous extraction. The biocatalytic system was further improved with the coexpression of an additional outer membrane transport system (AlkL) to increase the substrate transfer into the cell, resulting in the production of 4 g l–1 ω-hydroxy dodecanoic acid. We further summarized the most important aspects of the whole-cell process and thereupon discuss the limits of the applied oxygenation reactions referring to hydrogen peroxide, acetate and P450 concentrations that impact the efficiency of the production host negatively.
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Affiliation(s)
- Daniel Scheps
- Institute of Technical Biochemistry, University of Stuttgart, Allmandring 31, 70569, Stuttgart, Germany
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14
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Lorenz E, Klatte S, Wendisch VF. Reductive amination by recombinant Escherichia coli: whole cell biotransformation of 2-keto-3-methylvalerate to L-isoleucine. J Biotechnol 2013; 168:289-94. [PMID: 23831557 DOI: 10.1016/j.jbiotec.2013.06.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 06/17/2013] [Accepted: 06/24/2013] [Indexed: 10/26/2022]
Abstract
A whole cell biotransformation system for reductive amination has been studied in recombinant Escherichia coli cells. Reductive amination of 2-keto-3-methylvalerate to L-isoleucine by a two-enzyme-cascade was achieved by overproduction of endogenous L-alanine dependent transaminase AvtA and heterologous L-alanine dehydrogenase from Bacillus subtilis in recombinant E. coli. Up to 100 mM L-isoleucine were produced from 100 mM 2-keto-3-methylvalerate and 100 mM ammonium sulfate. Regeneration of NADH as cofactor in the whole cell system was driven by glucose catabolism. The effects of defined gene deletions in the central carbon metabolism on biotransformation were tested. Strains lacking the NuoG subunit of NADH:ubiquinone oxidoreductase (complex I) or aceA encoding the glyoxylate cycle enzyme isocitrate lyase exhibited increased biotransformation rates.
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Affiliation(s)
- Elisabeth Lorenz
- Chair of Genetics of Prokaryotes, Faculty of Biology & CeBiTec, Bielefeld University, D-33615 Bielefeld, Germany
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15
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Kang B, Zhang X, Wu Z, Qi H, Wang Z. Solubilization capacity of nonionic surfactant micelles exhibiting strong influence on export of intracellular pigments in Monascus fermentation. Microb Biotechnol 2013; 6:540-50. [PMID: 23425092 PMCID: PMC3918156 DOI: 10.1111/1751-7915.12039] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 01/07/2013] [Indexed: 11/01/2022] Open
Abstract
In this study, perstractive fermentation of intracellular Monascus pigments in nonionic surfactant micelle aqueous solution had been studied. The permeability of cell membrane modified by nonionic surfactant might have influence on the rate of export of intracellular pigments into its extracellular broth while nearly no effect on the final extracellular pigment concentration. However, the solubilization of pigments in nonionic surfactant micelles strongly affected the final extracellular pigment concentration. The solubilization capacity of micelles depended on the kind of nonionic surfactant, the super-molecule assembly structure of nonionic surfactant in an aqueous solution, and the nonionic surfactant concentration. Elimination of pigment degradation by export of intracellular Monascus pigments and solubilizing them into nonionic surfactant micelles was also confirmed experimentally. Thus, nonionic surfactant micelle aqueous solution is potential for replacement of organic solvent for perstractive fermentation of intracellular product.
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Affiliation(s)
- Biyu Kang
- School of Biological Science and Engineering, South China University of Technology, Guangzhou 510006, China
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16
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Olaofe OA, Fenner CJ, Gudiminchi RK, Smit MS, Harrison STL. The influence of microbial physiology on biocatalyst activity and efficiency in the terminal hydroxylation of n-octane using Escherichia coli expressing the alkane hydroxylase, CYP153A6. Microb Cell Fact 2013; 12:8. [PMID: 23351575 PMCID: PMC3598389 DOI: 10.1186/1475-2859-12-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 01/17/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Biocatalyst improvement through molecular and recombinant means should be complemented with efficient process design to facilitate process feasibility and improve process economics. This study focused on understanding the bioprocess limitations to identify factors that impact the expression of the terminal hydroxylase CYP153A6 and also influence the biocatalytic transformation of n-octane to 1-octanol using resting whole cells of recombinant E. coli expressing the CYP153A6 operon which includes the ferredoxin (Fdx) and the ferredoxin reductase (FdR). RESULTS Specific hydroxylation activity decreased with increasing protein expression showing that the concentration of active biocatalyst is not the sole determinant of optimum process efficiency. Process physiological conditions including the medium composition, temperature, glucose metabolism and product toxicity were investigated. A fed-batch system with intermittent glucose feeding was necessary to ease overflow metabolism and improve process efficiency while the introduction of a product sink (BEHP) was required to alleviate octanol toxicity. Resting cells cultivated on complex LB and glucose-based defined medium with similar CYP level (0.20 μmol gDCW-1) showed different biocatalyst activity and efficiency in the hydroxylation of octane over a period of 120 h. This was influenced by differing glucose uptake rate which is directly coupled to cofactor regeneration and cell energy in whole cell biocatalysis. The maximum activity and biocatalyst efficiency achieved presents a significant improvement in the use of CYP153A6 for alkane activation. This biocatalyst system shows potential to improve productivity if substrate transfer limitation across the cell membrane and enzyme stability can be addressed especially at higher temperature. CONCLUSION This study emphasises that the overall process efficiency is primarily dependent on the interaction between the whole cell biocatalyst and bioprocess conditions.
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Affiliation(s)
- Oluwafemi A Olaofe
- Centre for Bioprocess Engineering Research (CeBER), Department of Chemical Engineering, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town, South Africa
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Hu Z, Zhang X, Wu Z, Qi H, Wang Z. Export of intracellular Monascus pigments by two-stage microbial fermentation in nonionic surfactant micelle aqueous solution. J Biotechnol 2012; 162:202-9. [PMID: 23079078 DOI: 10.1016/j.jbiotec.2012.10.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Revised: 10/05/2012] [Accepted: 10/08/2012] [Indexed: 11/19/2022]
Abstract
Microbial fermentation of intracellular product is usually limited by high intracellular product concentration inhibition and complex downstream product processing. Perstractive fermentation of intracellular Monascus pigments in the nonionic surfactant Triton X-100 aqueous solution was studied in the present work, in which the intracellular product was exported from the intracellular to the extracellular aqueous solution and consecutively extracted into the nonionic surfactant micelles. After the second stage perstractive fermentation in the two-stage operation mode, biomass increased from 5 to 24 g/l DCW. The corresponding extracellular concentrations of yellow, orange, and red pigments were 60, 49 and 26 AU. The increase of cell density and the final pigment concentration were difficult to occur in a conventional aqueous medium using the two-stage fermentation. This positive effect of perstractive fermentation was ascribed to low intracellular pigment density, which eliminated the product inhibition and prevented the product from further degradation. The high efficiency of perstractive fermentation was further confirmed by fed-batch operation mode, in which the final biomass reached 28 g/l DCW and the corresponding extracellular concentrations of yellow, orange, and red pigments were 130, 84 and 47 AU.
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Affiliation(s)
- Zhiqiang Hu
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, PR China
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Production host selection for asymmetric styrene epoxidation: Escherichia coli vs. solvent-tolerant Pseudomonas. ACTA ACUST UNITED AC 2012; 39:1125-33. [DOI: 10.1007/s10295-012-1126-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 03/28/2012] [Indexed: 10/28/2022]
Abstract
Abstract
Selection of the ideal microbe is crucial for whole-cell biotransformations, especially if the target reaction intensively interacts with host cell functions. Asymmetric styrene epoxidation is an example of a reaction which is strongly dependent on the host cell owing to its requirement for efficient cofactor regeneration and stable expression of the styrene monooxygenase genes styAB. On the other hand, styrene epoxidation affects the whole-cell biocatalyst, because it involves toxic substrate and products besides the burden of additional (recombinant) enzyme synthesis. With the aim to compare two fundamentally different strain engineering strategies, asymmetric styrene epoxidation by StyAB was investigated using the engineered wild-type strain Pseudomonas sp. strain VLB120ΔC, a styrene oxide isomerase (StyC) knockout strain able to accumulate (S)-styrene oxide, and recombinant E. coli JM101 carrying styAB on the plasmid pSPZ10. Their performance was analyzed during fed-batch cultivation in two-liquid phase biotransformations with respect to specific activity, volumetric productivity, product titer, tolerance of toxic substrate and products, by-product formation, and product yield on glucose. Thereby, Pseudomonas sp. strain VLB120ΔC proved its great potential by tolerating high styrene oxide concentrations and by the absence of by-product formation. The E. coli-based catalyst, however, showed higher specific activities and better yields on glucose. The results not only show the importance but also the complexity of host cell selection and engineering. Finding the optimal strain engineering strategy requires profound understanding of bioprocess and biocatalyst operation. In this respect, a possible negative influence of solvent tolerance on yield and activity is discussed.
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Ni Y, Li CX, Zhang J, Shen ND, Bornscheuer UT, Xu JH. Efficient Reduction of Ethyl 2-Oxo-4-phenylbutyrate at 620 g⋅L−1 by a Bacterial Reductase with Broad Substrate Spectrum. Adv Synth Catal 2011. [DOI: 10.1002/adsc.201100132] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Kuhn D, Blank LM, Schmid A, Bühler B. Systems biotechnology - Rational whole-cell biocatalyst and bioprocess design. Eng Life Sci 2010. [DOI: 10.1002/elsc.201000009] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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Vennestrøm PN, Taarning E, Christensen C, Pedersen S, Grunwaldt JD, Woodley J. Chemoenzymatic Combination of Glucose Oxidase with Titanium Silicalite-1. ChemCatChem 2010. [DOI: 10.1002/cctc.201000120] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Wang Z, Dai Z. Extractive microbial fermentation in cloud point system. Enzyme Microb Technol 2010; 46:407-18. [DOI: 10.1016/j.enzmictec.2010.02.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2009] [Accepted: 02/07/2010] [Indexed: 10/19/2022]
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Bell SG, Dale A, Rees NH, Wong LL. A cytochrome P450 class I electron transfer system from Novosphingobium aromaticivorans. Appl Microbiol Biotechnol 2009; 86:163-75. [DOI: 10.1007/s00253-009-2234-y] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 08/14/2009] [Accepted: 08/28/2009] [Indexed: 10/20/2022]
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Blank LM, Ebert BE, Bühler B, Schmid A. Metabolic capacity estimation of Escherichia coli as a platform for redox biocatalysis: constraint-based modeling and experimental verification. Biotechnol Bioeng 2008; 100:1050-65. [PMID: 18553399 DOI: 10.1002/bit.21837] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Whole-cell redox biocatalysis relies on redox cofactor regeneration by the microbial host. Here, we applied flux balance analysis based on the Escherichia coli metabolic network to estimate maximal NADH regeneration rates. With this optimization criterion, simulations showed exclusive use of the pentose phosphate pathway at high rates of glucose catabolism, a flux distribution usually not found in wild-type cells. In silico, genetic perturbations indicated a strong dependency of NADH yield and formation rate on the underlying metabolic network structure. The linear dependency of measured epoxidation activities of recombinant central carbon metabolism mutants on glucose uptake rates and the linear correlation between measured activities and simulated NADH regeneration rates imply intracellular NADH shortage. Quantitative comparison of computationally predicted NADH regeneration and experimental epoxidation rates indicated that the achievable biocatalytic activity is determined by metabolic and enzymatic limitations including non-optimal flux distributions, high maintenance energy demands, energy spilling, byproduct formation, and uncoupling. The results are discussed in the context of cellular optimization of biotransformation processes and may guide a priori design of microbial cells as redox biocatalysts.
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Affiliation(s)
- Lars M Blank
- Laboratory of Chemical Biotechnology, TU Dortmund, D-44221 Dortmund, Germany.
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Recent trends in industrial microbiology. Curr Opin Microbiol 2008; 11:240-8. [DOI: 10.1016/j.mib.2008.04.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Revised: 04/21/2008] [Accepted: 04/28/2008] [Indexed: 02/04/2023]
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Gross R, Hauer B, Otto K, Schmid A. Microbial biofilms: new catalysts for maximizing productivity of long-term biotransformations. Biotechnol Bioeng 2008; 98:1123-34. [PMID: 17614329 DOI: 10.1002/bit.21547] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The performance of biocatalytic reactions is often hampered by product and/or substrate toxicity and short-term reaction times due to instable biocatalysts. Microbes in biofilms show a remarkable resistance against biocides and form stable communities. In nature, especially in environments characterized by harsh conditions such as heavily contaminated sites, cells grow pre-dominantly in biofilms, which enable them to cope with physiological stress. This robustness was utilized to design a bioprocess concept based on catalytic biofilms for stable long-term transformations of toxic reactants. Sixty-nine bacterial strains have been screened to find organisms suitable for biofilm-based biotransformations. This included host strains important for recombinant enzyme expression and strains isolated from biofilters or contaminated soils. Nearly all organisms with bioremediation potential showed good biofilm forming capacities. Pseudomonas sp. strain VLB120DeltaC was chosen as a model organism due to its excellent biofilm forming capacity and its well-studied capability of catalyzing asymmetric epoxidations. A tubular reactor was used for the biotransformation of styrene to (S)-styrene oxide as a model reaction. The process was stable for at least 55 days at a maximal volumetric productivity of 16 g/(L(aq) day) and a yield of 9 mol%. In situ product extraction prevented product inhibition of the catalyst. Biofilm physiology and dynamics are characterized during the biotransformation and limitations and advantages of this reaction concept are discussed.
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Affiliation(s)
- Rainer Gross
- Department of Biochemical and Chemical Engineering, University of Dortmund, Emil-Figge-Str. 66, 44221 Dortmund, Germany
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Heipieper HJ, Neumann G, Cornelissen S, Meinhardt F. Solvent-tolerant bacteria for biotransformations in two-phase fermentation systems. Appl Microbiol Biotechnol 2007; 74:961-73. [PMID: 17262209 DOI: 10.1007/s00253-006-0833-4] [Citation(s) in RCA: 227] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Revised: 12/22/2006] [Accepted: 12/25/2006] [Indexed: 11/30/2022]
Abstract
Product removal from aqueous media poses a challenge in biotechnological whole-cell biotransformation processes in which substrates and/or products may have toxic effects. The assignment of an additional liquid solvent phase provides a solution, as it facilitates in situ product recovery from aqueous media. In such two-phase systems, toxic substrates and products are present in the aqueous phase in tolerable but still bioavailable amounts. As a matter of course, adequate organic solvents have to possess hydrophobicity properties akin to substrates and products of interest, which in turn involves intrinsic toxicity of the solvents used. The employment of bacteria being able to adapt to otherwise toxic solvents helps to overcome the problem. Adaptive mechanisms enabling such solvent tolerant bacteria to survive and grow in the presence of toxic solvents generally involve either modification of the membrane and cell surface properties, changes in the overall energy status, or the activation and/or induction of active transport systems for extruding solvents from membranes into the environment. It is anticipated that the biotechnological production of a number of important fine chemicals in amounts sufficient to compete economically with chemical syntheses will soon be possible by making use of solvent-tolerant microorganisms.
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Affiliation(s)
- Hermann J Heipieper
- Department of Bioremediation, UFZ Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig, Germany.
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