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Hozumi Y, Hachisuka SI, Tomita H, Kikukawa H, Matsumoto K. Engineering of the Long-Main-Chain Monomer-Incorporating Polyhydroxyalkanoate Synthase PhaC AR for the Biosynthesis of Poly[( R)-3-hydroxybutyrate- co-6-hydroxyhexanoate]. Biomacromolecules 2024; 25:2973-2979. [PMID: 38588330 DOI: 10.1021/acs.biomac.4c00116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
Polyhydroxyalkanoate (PHA) synthases (PhaCs) are useful and versatile tools for the production of aliphatic polyesters. Here, the chimeric PHA synthase PhaCAR was engineered to increase its capacity to incorporate unusual 6-hydroxyhexanoate (6HHx) units. Mutations at positions 149 and 314 in PhaCAR were previously found to increase the incorporation of an analogous natural monomer, 3-hydroxyhexanoate (3HHx). We attempted to repurpose the mutations to produce 6HHx-containing polymers. Site-directed saturation mutants at these positions were applied for P(3HB-co-6HHx) synthesis in Escherichia coli. As a result, the N149D and F314Y mutants effectively increased the 6HHx fraction. Moreover, the pairwise NDFY mutation further increased the 6HHx fraction, which reached 22 mol %. This increase was presumably caused by altered enzyme activity rather than altered expression levels, as assessed based on immunoblot analysis. The glass transition temperature and crystallinity of P(3HB-co-6HHx) decreased as the 6HHx fraction increased.
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Affiliation(s)
- Yuka Hozumi
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, N13W8, Kitaku, Sapporo 060-8628, Japan
| | - Shin-Ichi Hachisuka
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, N13W8, Kitaku, Sapporo 060-8628, Japan
| | - Hiroya Tomita
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, N13W8, Kitaku, Sapporo 060-8628, Japan
| | - Hiroshi Kikukawa
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, N13W8, Kitaku, Sapporo 060-8628, Japan
| | - Ken'ichiro Matsumoto
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, N13W8, Kitaku, Sapporo 060-8628, Japan
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Manoli MT, Gargantilla-Becerra Á, Del Cerro Sánchez C, Rivero-Buceta V, Prieto MA, Nogales J. A model-driven approach to upcycling recalcitrant feedstocks in Pseudomonas putida by decoupling PHA production from nutrient limitation. Cell Rep 2024; 43:113979. [PMID: 38517887 DOI: 10.1016/j.celrep.2024.113979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 01/29/2024] [Accepted: 03/06/2024] [Indexed: 03/24/2024] Open
Abstract
Bacterial polyhydroxyalkanoates (PHAs) have emerged as promising eco-friendly alternatives to petroleum-based plastics since they are synthesized from renewable resources and offer exceptional properties. However, their production is limited to the stationary growth phase under nutrient-limited conditions, requiring customized strategies and costly two-phase bioprocesses. In this study, we tackle these challenges by employing a model-driven approach to reroute carbon flux and remove regulatory constraints using synthetic biology. We construct a collection of Pseudomonas putida-overproducing strains at the expense of plastics and lignin-related compounds using growth-coupling approaches. PHA production was successfully achieved during growth phase, resulting in the production of up to 46% PHA/cell dry weight while maintaining a balanced carbon-to-nitrogen ratio. Our strains are additionally validated under an upcycling scenario using enzymatically hydrolyzed polyethylene terephthalate as a feedstock. These findings have the potential to revolutionize PHA production and address the global plastic crisis by overcoming the complexities of traditional PHA production bioprocesses.
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Affiliation(s)
- Maria-Tsampika Manoli
- Polymer Biotechnology Group, Department of Microbial and Plant Biotechnology, Margarita Salas Center for Biological Research (CIB-CSIC), 28040 Madrid, Spain; Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), Madrid, Spain
| | - Álvaro Gargantilla-Becerra
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), Madrid, Spain; 3Systems Biotechnology Group, Department of Systems Biology, Centro Nacional de Biotecnología, CSIC, Madrid 28049, Spain
| | - Carlos Del Cerro Sánchez
- Polymer Biotechnology Group, Department of Microbial and Plant Biotechnology, Margarita Salas Center for Biological Research (CIB-CSIC), 28040 Madrid, Spain; Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), Madrid, Spain
| | - Virginia Rivero-Buceta
- Polymer Biotechnology Group, Department of Microbial and Plant Biotechnology, Margarita Salas Center for Biological Research (CIB-CSIC), 28040 Madrid, Spain; Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), Madrid, Spain
| | - M Auxiliadora Prieto
- Polymer Biotechnology Group, Department of Microbial and Plant Biotechnology, Margarita Salas Center for Biological Research (CIB-CSIC), 28040 Madrid, Spain; Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), Madrid, Spain.
| | - Juan Nogales
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), Madrid, Spain; 3Systems Biotechnology Group, Department of Systems Biology, Centro Nacional de Biotecnología, CSIC, Madrid 28049, Spain; CNB DNA Biofoundry (CNBio), CSIC, Madrid, Spain.
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Park S, Roh S, Yoo J, Ahn JH, Gong G, Lee SM, Um Y, Han SO, Ko JK. Tailored polyhydroxyalkanoate production from renewable non-fatty acid carbon sources using engineered Cupriavidus necator H16. Int J Biol Macromol 2024; 263:130360. [PMID: 38387639 DOI: 10.1016/j.ijbiomac.2024.130360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/14/2024] [Accepted: 02/19/2024] [Indexed: 02/24/2024]
Abstract
As thermoplastic, nontoxic, and biocompatible polyesters, polyhydroxyalkanoates (PHAs) are considered promising biodegradable plastic candidates for diverse applications. Short-chain-length/medium-chain-length (SCL/MCL) PHA copolymers are flexible and versatile PHAs that are typically produced from fatty acids, which are expensive and toxic. Therefore, to achieve the sustainable biosynthesis of SCL/MCL-PHAs from renewable non-fatty acid carbon sources (e.g., sugar or CO2), we used the lithoautotrophic bacterium Cupriavidus necator H16 as a microbial platform. Specifically, we synthesized tailored PHA copolymers with varying MCL-3-hydroxyalkanoate (3HA) compositions (10-70 mol%) from fructose by rewiring the MCL-3HA biosynthetic pathways, including (i) the thioesterase-mediated free fatty acid biosynthetic pathway coupled with the beta-oxidation cycle and (ii) the hydroxyacyl transferase-mediated fatty acid de novo biosynthetic pathway. In addition to sugar-based feedstocks, engineered strains are also promising platforms for the lithoautotrophic production of SCL/MCL-PHAs from CO2. The set of engineered C. necator strains developed in this study provides greater opportunities to produce customized polymers with controllable monomer compositions from renewable resources.
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Affiliation(s)
- Soyoung Park
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Soonjong Roh
- Biomaterials Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Jin Yoo
- Biomaterials Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Jung Ho Ahn
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul 02792, Republic of Korea
| | - Gyeongtaek Gong
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul 02792, Republic of Korea
| | - Sun-Mi Lee
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul 02792, Republic of Korea
| | - Youngsoon Um
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul 02792, Republic of Korea
| | - Sung Ok Han
- Department of Biotechnology, Graduate School, Korea University, Seoul 02841, Republic of Korea
| | - Ja Kyong Ko
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul 02792, Republic of Korea.
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Huong KH, Orita I, Fukui T. Microaerobic insights into production of polyhydroxyalkanoates containing 3-hydroxyhexanoate via native reverse β-oxidation from glucose in Ralstonia eutropha H16. Microb Cell Fact 2024; 23:21. [PMID: 38221622 PMCID: PMC10788006 DOI: 10.1186/s12934-024-02294-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 01/01/2024] [Indexed: 01/16/2024] Open
Abstract
BACKGROUND Ralstonia eutropha H16, a facultative chemolitoautotroph, is an important workhorse for bioindustrial production of useful compounds such as polyhydroxyalkanoates (PHAs). Despite the extensive studies to date, some of its physiological properties remain not fully understood. RESULTS This study demonstrated that the knallgas bacterium exhibited altered PHA production behaviors under slow-shaking condition, as compared to its usual aerobic condition. One of them was a notable increase in PHA accumulation, ranging from 3.0 to 4.5-fold in the mutants lacking of at least two NADPH-acetoacetyl-CoA reductases (PhaB1, PhaB3 and/or phaB2) when compared to their respective aerobic counterpart, suggesting the probable existence of (R)-3HB-CoA-providing route(s) independent on PhaBs. Interestingly, PHA production was still considerably high even with an excess nitrogen source under this regime. The present study further uncovered the conditional activation of native reverse β-oxidation (rBOX) allowing formation of (R)-3HHx-CoA, a crucial precursor for poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)], solely from glucose. This native rBOX led to the natural incorporation of 3.9 mol% 3HHx in a triple phaB-deleted mutant (∆phaB1∆phaB1∆phaB2-C2). Gene deletion experiments elucidated that the native rBOX was mediated by previously characterized (S)-3HB-CoA dehydrogenases (PaaH1/Had), β-ketothiolase (BktB), (R)-2-enoyl-CoA hydratase (PhaJ4a), and unknown crotonase(s) and reductase(s) for crotonyl-CoA to butyryl-CoA conversion prior to elongation. The introduction of heterologous enzymes, crotonyl-CoA carboxylase/reductase (Ccr) and ethylmalonyl-CoA decarboxylase (Emd) along with (R)-2-enoyl-CoA hydratase (PhaJ) aided the native rBOX, resulting in remarkably high 3HHx composition (up to 37.9 mol%) in the polyester chains under the low-aerated condition. CONCLUSION These findings shed new light on the robust characteristics of Ralstonia eutropha H16 and have the potential for the development of new strategies for practical P(3HB-co-3HHx) copolyesters production from sugars under low-aerated conditions.
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Affiliation(s)
- Kai-Hee Huong
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8501, Japan
| | - Izumi Orita
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8501, Japan
| | - Toshiaki Fukui
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8501, Japan.
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β-oxidation-polyhydroxyalkanoates synthesis relationship in Pseudomonas putida KT2440 revisited. Appl Microbiol Biotechnol 2023; 107:1863-1874. [PMID: 36763117 PMCID: PMC10006253 DOI: 10.1007/s00253-023-12413-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 01/20/2023] [Accepted: 01/25/2023] [Indexed: 02/11/2023]
Abstract
Pseudomonas putida KT2440 is a well-known model organism for the medium-chain-length (mcl) polyhydroxyalkanoate (PHA) accumulation. (R)-Specific enoyl-coenzyme A hydratase (PhaJ) was considered to be the main supplier of monomers for PHA synthesis by converting the β-oxidation intermediate, trans-2-enoyl-CoA to (R)-3-hydroxyacyl-CoA when fatty acids (FA) are used. Three PhaJ homologues, PhaJ1, PhaJ4 and MaoC, are annotated in P. putida KT2440. To investigate the relationship of fatty acids-PHA metabolism and the role of each PhaJ in PHA biosynthesis in P. putida KT2440, a series of P. putida KT2440 knockouts was obtained. PHA content and monomer composition in wild type (WT) and mutants under different growth conditions were analysed. PhaJ4 was the main monomer supplier for PHA synthesis with FA as sole carbon and energy source, with preference towards C8 and C10 substrate, whereas PhaJ1 showed preference for the C6 substrate. However, when all three PhaJ homologues were deleted, the mutant still accumulated PHA up to 10.7% of the cell dry weight (CDW). The deletion of (R)-3-hydroxydecanoyl-ACP:CoA transacylase (PhaG), which connects de novo FA and PHA synthesis pathways, while causing a further 1.8-fold decrease in PHA content, did not abolish PHA accumulation. Further proteome analysis revealed quinoprotein alcohol dehydrogenases PedE and PedH as potential monomer suppliers, but when these were deleted, the PHA level remained at 2.2-14.8% CDW depending on the fatty acid used and whether nitrogen limitation was applied. Therefore, it is likely that some other non-specific dehydrogenases supply monomers for PHA synthesis, demonstrating the redundancy of PHA metabolism. KEY POINTS: • β-oxidation intermediates are converted to PHA monomers by hydratases PhaJ1, PhaJ4 and MaoC in Pseudomonas putida KT2440. • When these are deleted, the PHA level decreases, but it is not abolished. • PHA non-specific enzyme(s) also contributes to PHA metabolism in KT2440.
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Zhuo XZ, Chou SC, Li SY. Producing medium-chain-length polyhydroxyalkanoate from diverse feedstocks by deregulating unsaturated fatty acid biosynthesis in Escherichia coli. BIORESOURCE TECHNOLOGY 2022; 365:128078. [PMID: 36216288 DOI: 10.1016/j.biortech.2022.128078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/01/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
The fatty acid metabolism in Escherichia coli has served as a basic metabolic chassis for medium-chain-length polyhydroxyalkanoate (mcl-PHA) production. In this study, the phaG and phaC1 genes from Pseudomonas entomophila L48 were first cloned as pGRN08. E. coli BL21P (E. coli BL21(DE3) ΔptsG) containing pGRN08 was able to produce 23 ± 3 and 7 ± 0 mg/L homopolymer poly(3-hydroxydecanoate)(P(3HD)) from glucose and xylose, respectively. Next, a gene, PSEEN0908 (encoding a putative 3-hydroxyacyl-CoA ligase), from P. entomophila L48 was found to increase the performance of mcl-PHA production. The induction of the fatty acid biosynthesis repressor (FabR), a transcription regulator that represses UFA biosynthesis, in E. coli substantially increased the mcl-PHA production by an order of magnitude from both unrelated and related carbon source conversion. A mcl-PHA concentration of 179 ± 1 mg/L and a content of 5.79 ± 0.16 % were obtained, where 31 mol% was 3-hydroxyoctanoate (3HO) and 69 mol% was 3HD.
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Affiliation(s)
- Xiao-Zhen Zhuo
- Department of Chemical Engineering, National Chung Hsing University, Taichung 402, Taiwan
| | - Shu-Chiao Chou
- Department of Chemical Engineering, National Chung Hsing University, Taichung 402, Taiwan
| | - Si-Yu Li
- Department of Chemical Engineering, National Chung Hsing University, Taichung 402, Taiwan; Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung 402, Taiwan.
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Thomas CM, Kumar D, Scheel RA, Ramarao B, Nomura CT. Production of Medium Chain Length polyhydroxyalkanoate copolymers from agro-industrial waste streams. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2022. [DOI: 10.1016/j.bcab.2022.102385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Satoh K, Kawakami T, Isobe N, Pasquier L, Tomita H, Zinn M, Matsumoto K. Versatile aliphatic polyester biosynthesis system for producing random and block copolymers composed of 2-, 3-, 4-, 5-, and 6-hydroxyalkanoates using the sequence-regulating polyhydroxyalkanoate synthase PhaC AR. Microb Cell Fact 2022; 21:84. [PMID: 35568875 PMCID: PMC9107728 DOI: 10.1186/s12934-022-01811-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 05/01/2022] [Indexed: 11/13/2022] Open
Abstract
Background Polyhydroxyalkanoates (PHAs) are microbial polyesters synthesized by PHA synthases. Naturally occurring PHA copolymers possess a random monomer sequence. The development of PhaCAR, a unique sequence-regulating PHA synthase, has enabled the spontaneous biosynthesis of PHA block copolymers. PhaCAR synthesizes both a block copolymer poly(2-hydroxybutyrate)-b-poly(3-hydroxybutyrate) [P(2HB)-b-P(3HB)], and a random copolymer, poly(3HB-co-3-hydroxyhexanoate), indicating that the combination of monomers determines the monomer sequence. Therefore, in this study, we explored the substrate scope of PhaCAR and the monomer sequences of the resulting copolymers to identify the determinants of the monomer sequence. PhaCAR is a class I PHA synthase that is thought to incorporate long-main-chain hydroxyalkanoates (LMC HAs, > C3 in the main [backbone] chain). Thus, the LMC monomers, 4-hydroxy-2-methylbutyrate (4H2MB), 5-hydroxyvalerate (5HV), and 6-hydroxyhexanoate (6HHx), as well as 2HB, 3HB, and 3-hydroxypropionate (3HP) were tested. Results Recombinant Escherichia coli harboring PhaCAR, CoA transferase and CoA ligase genes was used for PHA production. The medium contained the monomer precursors, 2HB, 3HB, 3HP, 4H2MB, 5HV, and 6HHx, either individually or in combination. As a result, homopolymers were obtained only for 3HB and 3HP. Moreover, 3HB and 3HP were randomly copolymerized by PhaCAR. 3HB-based binary copolymers P(3HB-co-LMC HA)s containing up to 2.9 mol% 4H2MB, 4.8 mol% 5HV, or 1.8 mol% 6HHx were produced. Differential scanning calorimetry analysis of the copolymers indicated that P(3HB-co-LMC HA)s had a random sequence. In contrast, combining 3HP and 2HB induced the synthesis of P(3HP)-b-P(2HB). Similarly, P(2HB) segment-containing block copolymers P(3HB-co-LMC HA)-b-P(2HB)s were synthesized. Binary copolymers of LMC HAs and 2HB were not obtained, indicating that the 3HB or 3HP unit is essential to the polymer synthesis. Conclusion PhaCAR possesses a wide substrate scope towards 2-, 3-, 4-, 5-, and 6-hydroxyalkanoates. 3HB or 3HP units are essential for polymer synthesis using PhaCAR. The presence of a 2HB monomer is key to synthesizing block copolymers, such as P(3HP)-b-P(2HB) and P(3HB-co-LMC HA)-b-P(2HB)s. The copolymers that did not contain 2HB units had a random sequence. This study’s results provide insights into the mechanism of sequence regulation by PhaCAR and pave the way for designing PHA block copolymers. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-022-01811-7.
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Affiliation(s)
- Keigo Satoh
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, N13W8, Kitaku, Sapporo, 060-8628, Japan
| | - Tomoya Kawakami
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, N13W8, Kitaku, Sapporo, 060-8628, Japan
| | - Nagi Isobe
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, N13W8, Kitaku, Sapporo, 060-8628, Japan
| | - Loïc Pasquier
- Department of Engineering, Hokkaido University, N13W8, Kitaku, Sapporo, 060-8628, Japan.,Institute of Life Technologies, University of Applied Sciences and Arts Western Switzerland (HES-SO Valais-Wallis), Sion, Switzerland
| | - Hiroya Tomita
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, N13W8, Kitaku, Sapporo, 060-8628, Japan
| | - Manfred Zinn
- Institute of Life Technologies, University of Applied Sciences and Arts Western Switzerland (HES-SO Valais-Wallis), Sion, Switzerland
| | - Ken'ichiro Matsumoto
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, N13W8, Kitaku, Sapporo, 060-8628, Japan.
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Metabolic engineering strategies to produce medium-chain oleochemicals via acyl-ACP:CoA transacylase activity. Nat Commun 2022; 13:1619. [PMID: 35338129 PMCID: PMC8956717 DOI: 10.1038/s41467-022-29218-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 03/04/2022] [Indexed: 11/12/2022] Open
Abstract
Microbial lipid metabolism is an attractive route for producing oleochemicals. The predominant strategy centers on heterologous thioesterases to synthesize desired chain-length fatty acids. To convert acids to oleochemicals (e.g., fatty alcohols, ketones), the narrowed fatty acid pool needs to be reactivated as coenzyme A thioesters at cost of one ATP per reactivation - an expense that could be saved if the acyl-chain was directly transferred from ACP- to CoA-thioester. Here, we demonstrate such an alternative acyl-transferase strategy by heterologous expression of PhaG, an enzyme first identified in Pseudomonads, that transfers 3-hydroxy acyl-chains between acyl-carrier protein and coenzyme A thioester forms for creating polyhydroxyalkanoate monomers. We use it to create a pool of acyl-CoA’s that can be redirected to oleochemical products. Through bioprospecting, mutagenesis, and metabolic engineering, we develop three strains of Escherichia coli capable of producing over 1 g/L of medium-chain free fatty acids, fatty alcohols, and methyl ketones. Microbial production of oleochemicals involves strategies of expressing thioesterase to narrow the substrate pool for the termination enzyme at the expense of one ATP. Here, the authors developed an alternative energy-efficient strategy to use of an acyl-ACP transacylase to produce medium chain oleochemicals in E. coli.
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Phan HT, Hosoe Y, Guex M, Tomoi M, Tomita H, Zinn M, Matsumoto K. Directed Evolution of Sequence-Regulating Polyhydroxyalkanoate Synthase to Synthesize a Medium-Chain-Length-Short-Chain-Length (MCL-SCL) Block Copolymer. Biomacromolecules 2022; 23:1221-1231. [PMID: 34991313 DOI: 10.1021/acs.biomac.1c01480] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Sequence-regulating polyhydroxyalkanoate synthase PhaCAR is a chimeric enzyme comprising PhaCs from Aeromonas caviae and Ralstonia eutropha (Cupriavidus necator). It spontaneously synthesizes a short-chain-length (SCL, ≤C5) block copolymer poly(2-hydroxybutyrate)-b-poly(3-hydroxybutyrate) [P(2HB)-b-P(3HB)] from a mixture of monomer substrates. In this study, directed evolution of PhaCAR was performed to increase its activity toward a medium-chain-length (MCL, C6-12) monomer, 3-hydroxyhexanoyl (3HHx)-coenzyme A (CoA). Random mutagenesis and selection based on P(3HB-co-3HHx) production in Escherichia coli found that beneficial mutations N149D and F314L increase the 3HHx fraction. The site-directed saturation mutagenesis at position 314, which is adjacent to the catalytic center C315, demonstrated that F314H synthesizes the P(3HHx) homopolymer. The F314H mutant exhibited increased activity toward 3HHx-CoA compared with the parent enzyme, whereas the activity toward 3HB-CoA decreased. The predicted tertiary structure of PhaCAR by AlphaFold2 provided insight into the mechanism of the beneficial mutations. In addition, this finding enabled the synthesis of a new PHA block copolymer, P(3HHx)-b-P(2HB). Solvent fractionation indicated the presence of a covalent linkage between the polymer segments. This novel MCL-SCL block copolymer considerably expands the range of the molecular design of PHA block copolymers.
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Affiliation(s)
- Hien Thi Phan
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Yumi Hosoe
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Maureen Guex
- Institute of Life Technologies, University of Applied Sciences and Arts Western Switzerland (HES-SO Valais-Wallis), 1950 Sion, Switzerland
| | - Masayoshi Tomoi
- Course of Applied Chemistry, Department of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Hiroya Tomita
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Manfred Zinn
- Institute of Life Technologies, University of Applied Sciences and Arts Western Switzerland (HES-SO Valais-Wallis), 1950 Sion, Switzerland
| | - Ken'ichiro Matsumoto
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
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11
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Tomita H, Satoh K, Nomura CT, Matsumoto K. Biosynthesis of poly(glycolate-co-3-hydroxybutyrate-co-3-hydroxyhexanoate) in Escherichia coli expressing sequence-regulating polyhydroxyalkanoate synthase and medium-chain-length 3-hydroxyalkanoic acid coenzyme A ligase. Biosci Biotechnol Biochem 2021; 86:217-223. [PMID: 34788370 DOI: 10.1093/bbb/zbab198] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 11/04/2021] [Indexed: 11/13/2022]
Abstract
Chimeric polyhydroxyalkanoate synthase PhaCAR is characterized by the capacity to incorporate unusual glycolate (GL) units and spontaneously synthesize block copolymers. The GL and 3-hydroxybutyrate (3HB) copolymer synthesized by PhaCAR is a random-homo block copolymer, poly(GL-ran-3HB)-b-poly(3HB). In the present study, medium-chain-length 3-hydroxyhexanoate (3HHx) units were incorporated into this copolymer using PhaCAR for the first time. The coenzyme A (CoA) ligase from Pseudomonas oleovorans (AlkK) serves as a simple 3HHx-CoA supplying route in Escherichia coli from exogenously supplemented 3HHx. NMR analyses of the obtained polymers revealed that 3HHx units were randomly connected to 3HB units, whereas GL units were heterogeneously distributed. Therefore, the polymer is composed of two segments: P(3HB-co-3HHx) and P(GL-co-3HB-co-3HHx). The thermal and mechanical properties of the terpolymer indicate no contiguous P(3HB) segments in the material, consistent with the NMR results. Therefore, PhaCAR synthesized the novel block copolymer P(3HB-co-3HHx)-b-P(GL-co-3HB-co-3HHx), which is the first block PHA copolymer comprising two copolymer segments.
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Affiliation(s)
- Hiroya Tomita
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, N13W8, Kitaku, Sapporo 060-8628, Japan
| | - Keigo Satoh
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, N13W8, Kitaku, Sapporo 060-8628, Japan
| | - Christopher T Nomura
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, Moscow, ID, 83844, USA
| | - Ken'ichiro Matsumoto
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, N13W8, Kitaku, Sapporo 060-8628, Japan
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12
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Koutinas M, Kyriakou M, Andreou K, Hadjicharalambous M, Kaliviotis E, Pasias D, Kazamias G, Varavvas C, Vyrides I. Enhanced biodegradation and valorization of drilling wastewater via simultaneous production of biosurfactants and polyhydroxyalkanoates by Pseudomonas citronellolis SJTE-3. BIORESOURCE TECHNOLOGY 2021; 340:125679. [PMID: 34364084 DOI: 10.1016/j.biortech.2021.125679] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/25/2021] [Accepted: 07/26/2021] [Indexed: 06/13/2023]
Abstract
Pseudomonas citronellolis SJTE-3 was isolated as a highly efficient microorganism for biodegradation and valorization of drilling fluids (DF) wastewater. The strain metabolised DF and oily mud exhibiting up to 93%, 86%, 85% and 88% of chemical oxygen demand (COD), n-dodecane, n-tetradecane and naphthalene removal efficiency respectively. Enhanced bioconversion was enabled through production of biosurfactants that reduced the surface tension of water by 53% and resulted in 43.3% emulsification index (E24), while synthesizing 24% of dry cell weight (DCW) as medium-chain-length polyhydroxyalkanoates (PHA). Expression from the main pathways for alkanes and naphthalene biodegradation as well as biosurfactants and PHA biosynthesis revealed that although the alkanes and naphthalene biodegradation routes were actively expressed even at stationary phase, PHA production was stimulated at late stationary phase and putisolvin could comprise the biosurfactant synthesized. The bioconversion of toxic petrochemical residues to added-value thermoelastomers and biosurfactants indicate the high industrial significance of P. citronellolis SJTE-3.
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Affiliation(s)
- Michalis Koutinas
- Department of Chemical Engineering, Cyprus University of Technology, 30 Archbishop Kyprianou Str., 3036, Limassol, Cyprus.
| | - Maria Kyriakou
- Department of Chemical Engineering, Cyprus University of Technology, 30 Archbishop Kyprianou Str., 3036, Limassol, Cyprus
| | - Kostas Andreou
- Department of Chemical Engineering, Cyprus University of Technology, 30 Archbishop Kyprianou Str., 3036, Limassol, Cyprus
| | - Michalis Hadjicharalambous
- Innovating Environmental Solutions Center (IESC) Ltd, 33 Spyrou Kyprianou Str., 3(rd) Industrial Area, Agios Sylas, 4193, Ypsonas, Limassol, Cyprus
| | - Efstathios Kaliviotis
- Department of Mechanical Engineering and Material Science and Engineering, Cyprus University of Technology, 45 Kitiou Kyprianou Str., 3041, Limassol, Cyprus
| | - Dimitris Pasias
- Department of Mechanical Engineering and Material Science and Engineering, Cyprus University of Technology, 45 Kitiou Kyprianou Str., 3041, Limassol, Cyprus
| | - George Kazamias
- Innovating Environmental Solutions Center (IESC) Ltd, 33 Spyrou Kyprianou Str., 3(rd) Industrial Area, Agios Sylas, 4193, Ypsonas, Limassol, Cyprus
| | - Costas Varavvas
- Innovating Environmental Solutions Center (IESC) Ltd, 33 Spyrou Kyprianou Str., 3(rd) Industrial Area, Agios Sylas, 4193, Ypsonas, Limassol, Cyprus
| | - Ioannis Vyrides
- Department of Chemical Engineering, Cyprus University of Technology, 30 Archbishop Kyprianou Str., 3036, Limassol, Cyprus
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13
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Samrot AV, Samanvitha SK, Shobana N, Renitta ER, Senthilkumar P, Kumar SS, Abirami S, Dhiva S, Bavanilatha M, Prakash P, Saigeetha S, Shree KS, Thirumurugan R. The Synthesis, Characterization and Applications of Polyhydroxyalkanoates (PHAs) and PHA-Based Nanoparticles. Polymers (Basel) 2021; 13:3302. [PMID: 34641118 PMCID: PMC8512352 DOI: 10.3390/polym13193302] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/31/2021] [Accepted: 08/31/2021] [Indexed: 12/22/2022] Open
Abstract
Polyhydroxyalkanoates (PHAs) are storage granules found in bacteria that are essentially hydroxy fatty acid polyesters. PHA molecules appear in variety of structures, and amongst all types of PHAs, polyhydroxybutyrate (PHB) is used in versatile fields as it is a biodegradable, biocompatible, and ecologically safe thermoplastic. The unique physicochemical characteristics of these PHAs have made them applicable in nanotechnology, tissue engineering, and other biomedical applications. In this review, the optimization, extraction, and characterization of PHAs are described. Their production and application in nanotechnology are also portrayed in this review, and the precise and various production methods of PHA-based nanoparticles, such as emulsion solvent diffusion, nanoprecipitation, and dialysis are discussed. The characterization techniques such as UV-Vis, FTIR, SEM, Zeta Potential, and XRD are also elaborated.
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Affiliation(s)
- Antony V. Samrot
- School of Bioscience, Faculty of Medicine, Bioscience and Nursing, MAHSA University, Jalan SP2, Bandar Saujana Putra, Jenjarom 42610, Selangor, Malaysia
| | - Sree K. Samanvitha
- Department of Biotechnology, Shanmugha Arts, Science, Technology & Research Academy, Thanjavur 613401, Tamil Nadu, India;
| | - N. Shobana
- Department of Biotechnology, School of Bio and Chemical Engineering, Sathyabama Institute of Science and Technology, Chennai 600119, Tamil Nadu, India; (N.S.); (M.B.); (P.P.); (S.S.); (K.S.S.)
| | - Emilin R. Renitta
- Department of Food Processing Technology, School of Agriculture and Biosciences, Karunya Institute of Science and Technology, Karunya Nagar, Coimbatore, 641114, Tamil Nadu, India;
| | - P. Senthilkumar
- Department of Chemical Engineering, School of Bio and Chemical Engineering, Sathyabama Institute of Science and Technology, Chennai 600119, Tamil Nadu, India;
| | - Suresh S. Kumar
- Centre for Materials Engineering and Regenerative Medicine, Bharath Institute of Higher Education and Research, Chennai 600126, Tamil Nadu, India
| | - S. Abirami
- Department of Microbiology, Kamaraj College, Thoothukudi 628003, Tamil Nadu, India;
| | - S. Dhiva
- Department of Microbiology, Sree Narayana College, Alathur, Palakkad 678682, Kerala, India;
| | - M. Bavanilatha
- Department of Biotechnology, School of Bio and Chemical Engineering, Sathyabama Institute of Science and Technology, Chennai 600119, Tamil Nadu, India; (N.S.); (M.B.); (P.P.); (S.S.); (K.S.S.)
| | - P. Prakash
- Department of Biotechnology, School of Bio and Chemical Engineering, Sathyabama Institute of Science and Technology, Chennai 600119, Tamil Nadu, India; (N.S.); (M.B.); (P.P.); (S.S.); (K.S.S.)
| | - S. Saigeetha
- Department of Biotechnology, School of Bio and Chemical Engineering, Sathyabama Institute of Science and Technology, Chennai 600119, Tamil Nadu, India; (N.S.); (M.B.); (P.P.); (S.S.); (K.S.S.)
| | - Krithika S. Shree
- Department of Biotechnology, School of Bio and Chemical Engineering, Sathyabama Institute of Science and Technology, Chennai 600119, Tamil Nadu, India; (N.S.); (M.B.); (P.P.); (S.S.); (K.S.S.)
| | - R. Thirumurugan
- Department of Transfusion Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry 605006, India;
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14
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Mitra R, Xu T, Chen GQ, Xiang H, Han J. An updated overview on the regulatory circuits of polyhydroxyalkanoates synthesis. Microb Biotechnol 2021; 15:1446-1470. [PMID: 34473895 PMCID: PMC9049629 DOI: 10.1111/1751-7915.13915] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 08/20/2021] [Accepted: 08/23/2021] [Indexed: 11/30/2022] Open
Abstract
Polyhydroxyalkanoates (PHA) are a promising and sustainable alternative to the petroleum‐based synthetic plastics. Regulation of PHA synthesis is receiving considerable importance as engineering the regulatory factors might help developing strains with improved PHA‐producing abilities. PHA synthesis is dedicatedly regulated by a number of regulatory networks. They tightly control the PHA content, granule size and their distribution in cells. Most PHA‐accumulating microorganisms have multiple regulatory networks that impart a combined effect on PHA metabolism. Among them, several factors ranging from global to specific regulators, have been identified and characterized till now. This review is an attempt to categorically summarize the diverse regulatory circuits that operate in some important PHA‐producing microorganisms. However, in several organisms, the detailed mechanisms involved in the regulation of PHA synthesis is not well‐explored and hence further research is needed. The information presented in this review might help researcher to identify the prevailing research gaps in PHA regulation.
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Affiliation(s)
- Ruchira Mitra
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,International College, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Tong Xu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Guo-Qiang Chen
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Hua Xiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jing Han
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, 100049, China
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15
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Lhamo P, Behera SK, Mahanty B. Process optimization, metabolic engineering interventions and commercialization of microbial polyhydroxyalkanoates production - A state-of-the art review. Biotechnol J 2021; 16:e2100136. [PMID: 34132046 DOI: 10.1002/biot.202100136] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/29/2021] [Accepted: 06/03/2021] [Indexed: 12/31/2022]
Abstract
Microbial polyhydroxyalkanoates (PHAs) produced using renewable resources could be the best alternative for conventional plastics. Despite their incredible potential, commercial production of PHAs remains very low. Nevertheless, sincere attempts have been made by researchers to improve the yield and economic viability of PHA production by utilizing low-cost agricultural or industrial wastes. In this context, the use of efficient microbial culture or consortia, adoption of experimental design to trace ideal growth conditions, nutritional requirements, and intervention of metabolic engineering tools have gained significant attention. This review has been structured to highlight the important microbial sources for PHA production, use of conventional and non-conventional substrates, product optimization using experimental design, metabolic engineering strategies, and global players in the commercialization of PHA in the past two decades. The challenges about PHA recovery and analysis have also been discussed which possess indirect hurdle while expanding the horizon of PHA-based bioplastics. Selection of appropriate microorganism and substrate plays a vital role in improving the productivity and characteristics of PHAs. Experimental design-based bioprocess, use of metabolic engineering tools, and optimal product recovery techniques are invaluable in this dimension. Optimization strategies, which are being explored in isolation, need to be logically integrated for the successful commercialization of microbial PHAs.
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Affiliation(s)
- Pema Lhamo
- Department of Biotechnology, Karunya Institute of Technology and Sciences, Coimbatore, Tamil Nadu, India
| | - Shishir Kumar Behera
- Industrial Ecology Research Group, School of Chemical Engineering, Vellore Institute of Technology, Vellore, Tamil Nadu, India
| | - Biswanath Mahanty
- Department of Biotechnology, Karunya Institute of Technology and Sciences, Coimbatore, Tamil Nadu, India
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16
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Blanco FG, Hernández N, Rivero-Buceta V, Maestro B, Sanz JM, Mato A, Hernández-Arriaga AM, Prieto MA. From Residues to Added-Value Bacterial Biopolymers as Nanomaterials for Biomedical Applications. NANOMATERIALS 2021; 11:nano11061492. [PMID: 34200068 PMCID: PMC8228158 DOI: 10.3390/nano11061492] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/20/2021] [Accepted: 05/26/2021] [Indexed: 12/16/2022]
Abstract
Bacterial biopolymers are naturally occurring materials comprising a wide range of molecules with diverse chemical structures that can be produced from renewable sources following the principles of the circular economy. Over the last decades, they have gained substantial interest in the biomedical field as drug nanocarriers, implantable material coatings, and tissue-regeneration scaffolds or membranes due to their inherent biocompatibility, biodegradability into nonhazardous disintegration products, and their mechanical properties, which are similar to those of human tissues. The present review focuses upon three technologically advanced bacterial biopolymers, namely, bacterial cellulose (BC), polyhydroxyalkanoates (PHA), and γ-polyglutamic acid (PGA), as models of different carbon-backbone structures (polysaccharides, polyesters, and polyamides) produced by bacteria that are suitable for biomedical applications in nanoscale systems. This selection models evidence of the wide versatility of microorganisms to generate biopolymers by diverse metabolic strategies. We highlight the suitability for applied sustainable bioprocesses for the production of BC, PHA, and PGA based on renewable carbon sources and the singularity of each process driven by bacterial machinery. The inherent properties of each polymer can be fine-tuned by means of chemical and biotechnological approaches, such as metabolic engineering and peptide functionalization, to further expand their structural diversity and their applicability as nanomaterials in biomedicine.
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Affiliation(s)
- Francisco G. Blanco
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), 28040 Madrid, Spain; (F.G.B.); (N.H.); (V.R.-B.); (A.M.); (A.M.H.-A.)
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain
| | - Natalia Hernández
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), 28040 Madrid, Spain; (F.G.B.); (N.H.); (V.R.-B.); (A.M.); (A.M.H.-A.)
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain
| | - Virginia Rivero-Buceta
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), 28040 Madrid, Spain; (F.G.B.); (N.H.); (V.R.-B.); (A.M.); (A.M.H.-A.)
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain
| | - Beatriz Maestro
- Host-Parasite Interplay in Pneumococcal Infection Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain; (B.M.); (J.M.S.)
| | - Jesús M. Sanz
- Host-Parasite Interplay in Pneumococcal Infection Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain; (B.M.); (J.M.S.)
| | - Aránzazu Mato
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), 28040 Madrid, Spain; (F.G.B.); (N.H.); (V.R.-B.); (A.M.); (A.M.H.-A.)
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain
| | - Ana M. Hernández-Arriaga
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), 28040 Madrid, Spain; (F.G.B.); (N.H.); (V.R.-B.); (A.M.); (A.M.H.-A.)
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain
| | - M. Auxiliadora Prieto
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), 28040 Madrid, Spain; (F.G.B.); (N.H.); (V.R.-B.); (A.M.); (A.M.H.-A.)
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain
- Correspondence:
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17
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Abstract
Abstract
Polyhydroxyalkanoates (PHAs) are linear semicrystalline polyesters produced naturally by a wide range of microorganisms for carbon and energy storage. PHAs can be used as replacements for petroleum-based polyethylene (PE) and polypropylene (PP) in many industrial applications due to their biodegradability, excellent barrier, mechanical, and thermal properties. The overall industrial applications of PHAs are still very limited due to the high production cost and high stiffness and brittleness. Therefore, new novel cost-effective production method must be considered for the new generation of PHAs. One approach is based on using different type feedstocks and biowastes including food byproducts and industrial and manufacturing wastes, can lead to more competitive and cost-effective PHAs products. Modification of PHAs with different function groups such as carboxylic, hydroxyl, amine, epoxy, etc. is also a relatively new approach to create new functional materials with different industrial applications. In addition, blending PHA with biodegradable materials such as polylactide (PLA), poly(ε-caprolactone) (PCL), starch, and distiller’s dried grains with solubles (DDGS) is another approach to address the drawbacks of PHAs and will be summarized in this chapter. A series of compatibilizers with different architectures were successfully synthesized and used to improve the compatibility and interfacial adhesion between PHAs and PCL. Finer morphology and significantly improvement in the mechanical properties of PHA/PCL blends were observed with a certain type of block compatibilizer. In addition, the improvement in the blend morphology and mechanical properties were found to be strongly influenced by the compatibilizer architecture.
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Affiliation(s)
- Samy A. Madbouly
- School of Engineering , Behrend College, Pennsylvania State University , Erie , PA 16563 , USA
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18
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Scheel RA, Ho T, Kageyama Y, Masisak J, McKenney S, Lundgren BR, Nomura CT. Optimizing a Fed-Batch High-Density Fermentation Process for Medium Chain-Length Poly(3-Hydroxyalkanoates) in Escherichia coli. Front Bioeng Biotechnol 2021; 9:618259. [PMID: 33718339 PMCID: PMC7953831 DOI: 10.3389/fbioe.2021.618259] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 02/08/2021] [Indexed: 11/15/2022] Open
Abstract
Production of medium chain-length poly(3-hydroxyalkanoates) [PHA] polymers with tightly defined compositions is an important area of research to expand the application and improve the properties of these promising biobased and biodegradable materials. PHA polymers with homopolymeric or defined compositions exhibit attractive material properties such as increased flexibility and elasticity relative to poly(3-hydroxybutyrate) [PHB]; however, these polymers are difficult to biosynthesize in native PHA-producing organisms, and there is a paucity of research toward developing high-density cultivation methods while retaining compositional control. In this study, we developed and optimized a fed-batch fermentation process in a stirred tank reactor, beginning with the biosynthesis of poly(3-hydroxydecanoate) [PHD] from decanoic acid by β-oxidation deficient recombinant Escherichia coli LSBJ using glucose as a co-substrate solely for growth. Bacteria were cultured in two stages, a biomass accumulation stage (37°C, pH 7.0) with glucose as the primary carbon source and a PHA biosynthesis stage (30°C, pH 8.0) with co-feeding of glucose and a fatty acid. Through iterative optimizations of semi-defined media composition and glucose feed rate, 6.0 g of decanoic acid was converted to PHD with an 87.5% molar yield (4.54 g L-1). Stepwise increases in the amount of decanoic acid fed during the fermentation correlated with an increase in PHD, resulting in a final decanoic acid feed of 25 g converted to PHD at a yield of 89.4% (20.1 g L-1, 0.42 g L-1 h-1), at which point foaming became uncontrollable. Hexanoic acid, octanoic acid, 10-undecenoic acid, and 10-bromodecanoic acid were all individually supplemented at 20 g each and successfully polymerized with yields ranging from 66.8 to 99.0% (9.24 to 18.2 g L-1). Using this bioreactor strategy, co-fatty acid feeds of octanoic acid/decanoic acid and octanoic acid/10-azidodecanoic acid (8:2 mol ratio each) resulted in the production of their respective copolymers at nearly the same ratio and at high yield, demonstrating that these methods can be used to control PHA copolymer composition.
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Affiliation(s)
- Ryan A. Scheel
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States
| | - Truong Ho
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States
| | - Yuki Kageyama
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States
- Division of Applied Chemistry, Department of Engineering, Hokkaido University, Sapporo, Japan
| | - Jessica Masisak
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States
| | - Seamus McKenney
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States
| | - Benjamin R. Lundgren
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States
| | - Christopher T. Nomura
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States
- Department of Biological Sciences, College of Science, University of Idaho, Moscow, ID, United States
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19
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Ai M, Zhu Y, Jia X. Recent advances in constructing artificial microbial consortia for the production of medium-chain-length polyhydroxyalkanoates. World J Microbiol Biotechnol 2021; 37:2. [PMID: 33392870 DOI: 10.1007/s11274-020-02986-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/20/2020] [Indexed: 11/29/2022]
Abstract
Polyhydroxyalkanoates (PHAs) are a class of high-molecular-weight polyesters made from hydroxy fatty acid monomers. PHAs produced by microorganisms have diverse structures, variable physical properties, and good biodegradability. They exhibit similar physical properties to petroleum-based plastics but are much more environmentally friendly. Medium-chain-length polyhydroxyalkanoates (mcl-PHAs), in particular, have attracted much interest because of their low crystallinity, low glass transition temperature, low tensile strength, high elongation at break, and customizable structure. Nevertheless, high production costs have hindered their practical application. The use of genetically modified organisms can reduce production costs by expanding the scope of substrate utilization, improving the conversion efficiency of substrate to product, and increasing the yield of mcl-PHAs. The yield of mcl-PHAs produced by a pure culture of an engineered microorganism was not high enough because of the limitations of the metabolic capacity of a single microorganism. The construction of artificial microbial consortia and the optimization of microbial co-cultivation have been studied. This type of approach avoids the addition of precursor substances and helps synthesize mcl-PHAs more efficiently. In this paper, we reviewed the design and construction principles and optimized control strategies for artificial microbial consortia that produce mcl-PHAs. We described the metabolic advantages of co-cultivating artificial microbial consortia using low-value substrates and discussed future perspectives on the production of mcl-PHAs using artificial microbial consortia.
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Affiliation(s)
- Mingmei Ai
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Yinzhuang Zhu
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Xiaoqiang Jia
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China.
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, China.
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20
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Liu CH, Chen HY, Chen YLL, Sheu DS. The polyhydroxyalkanoate (PHA) synthase 1 of Pseudomonas sp. H9 synthesized a 3-hydroxybutyrate-dominant hybrid of short- and medium-chain-length PHA. Enzyme Microb Technol 2020; 143:109719. [PMID: 33375979 DOI: 10.1016/j.enzmictec.2020.109719] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/20/2020] [Accepted: 11/26/2020] [Indexed: 12/30/2022]
Abstract
Pseudomonas sp. H9 (H9), an environmental strain isolated from a riverbank soil sample collected in southern Taiwan, is Gram-negative and shares a 99 % sequence identity to Pseudomonas putida KT2440 based on 16S rRNA gene analysis. H9 produced novel polyhydroxyalkanoates (PHA) including a hybrid PHA, comprised of 3-hydroxyvalerate (37 mol%) and medium-chain-length (MCL) monomers from valerate, as well as a 3-hydroxyhexanoate-dominant (93 mol%) MCL-PHA from hexanoate. Next-generation sequencing analysis showed H9 had a typical class II PHA operon, consisted of phaC1H9-phaZH9-phaC2H9, in which phaC1H9 was the sole active PHA synthase in H9. Deletion of phaC1H9 gene led to a complete loss of its PHA accumulation capability. Knockout of phaC2H9 gene, in contrast, affected neither bacterial growth nor PHA accumulation. When co-expressed with the phaAB genes of Ralstonia eutropha H16 in the PHA mutant strain Pseudomonas sp. H9ΔC1, phaC1H9 synthesized a hybrid PHA consisted of 3-hydroxybutyrate (3HB) (75 mol%) and MCL-monomers, confirmed in analyses using hot-acetone fractionation and 13C-NMR spectroscopy. As a novel PHA synthase, PhaC1H9 possesses a broad substrate specificity to synthesize a hybrid of SCL- and MCL-PHA, known to have many mechanical properties for potential applications.
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Affiliation(s)
- Chung-Hsien Liu
- Department of Marine Biotechnology, National Kaohsiung University of Science and Technology, Kaohsiung, 81157, Taiwan
| | - Houng-Yung Chen
- Department of Oceanography, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| | - Yuh-Ling Lee Chen
- Department of Oceanography, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| | - Der-Shyan Sheu
- Department of Marine Biotechnology, National Kaohsiung University of Science and Technology, Kaohsiung, 81157, Taiwan; Department of Oceanography, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan.
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21
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Mezzina MP, Manoli MT, Prieto MA, Nikel PI. Engineering Native and Synthetic Pathways in Pseudomonas putida for the Production of Tailored Polyhydroxyalkanoates. Biotechnol J 2020; 16:e2000165. [PMID: 33085217 DOI: 10.1002/biot.202000165] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/16/2020] [Indexed: 12/16/2022]
Abstract
Growing environmental concern sparks renewed interest in the sustainable production of (bio)materials that can replace oil-derived goods. Polyhydroxyalkanoates (PHAs) are isotactic polymers that play a critical role in the central metabolism of producer bacteria, as they act as dynamic reservoirs of carbon and reducing equivalents. PHAs continue to attract industrial attention as a starting point toward renewable, biodegradable, biocompatible, and versatile thermoplastic and elastomeric materials. Pseudomonas species have been known for long as efficient biopolymer producers, especially for medium-chain-length PHAs. The surge of synthetic biology and metabolic engineering approaches in recent years offers the possibility of exploiting the untapped potential of Pseudomonas cell factories for the production of tailored PHAs. In this article, an overview of the metabolic and regulatory circuits that rule PHA accumulation in Pseudomonas putida is provided, and approaches leading to the biosynthesis of novel polymers (e.g., PHAs including nonbiological chemical elements in their structures) are discussed. The potential of novel PHAs to disrupt existing and future market segments is closer to realization than ever before. The review is concluded by pinpointing challenges that currently hinder the wide adoption of bio-based PHAs, and strategies toward programmable polymer biosynthesis from alternative substrates in engineered P. putida strains are proposed.
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Affiliation(s)
- Mariela P Mezzina
- Systems Environmental Microbiology Group, The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs Lyngby, 2800, Denmark
| | - María Tsampika Manoli
- Microbial and Plant Biotechnology Department, Centro de Investigaciones Biológicas «Margarita Salas» (CIB-CSIC), Polymer Biotechnology Group, Madrid, 28040, Spain.,Spanish National Research Council (SusPlast-CSIC), Interdisciplinary Platform for Sustainable Plastics Toward a Circular Economy, Madrid, 28040, Spain
| | - M Auxiliadora Prieto
- Microbial and Plant Biotechnology Department, Centro de Investigaciones Biológicas «Margarita Salas» (CIB-CSIC), Polymer Biotechnology Group, Madrid, 28040, Spain.,Spanish National Research Council (SusPlast-CSIC), Interdisciplinary Platform for Sustainable Plastics Toward a Circular Economy, Madrid, 28040, Spain
| | - Pablo I Nikel
- Systems Environmental Microbiology Group, The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs Lyngby, 2800, Denmark
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22
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Adeleye AT, Odoh CK, Enudi OC, Banjoko OO, Osiboye OO, Toluwalope Odediran E, Louis H. Sustainable synthesis and applications of polyhydroxyalkanoates (PHAs) from biomass. Process Biochem 2020. [DOI: 10.1016/j.procbio.2020.05.032] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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23
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Hernández Lozada NJ, Simmons TR, Xu K, Jindra MA, Pfleger BF. Production of 1-octanol in Escherichia coli by a high flux thioesterase route. Metab Eng 2020; 61:352-359. [PMID: 32707169 DOI: 10.1016/j.ymben.2020.07.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/10/2020] [Accepted: 07/07/2020] [Indexed: 10/23/2022]
Abstract
1-octanol is a valuable molecule in the chemical industry, where it is used as a plasticizer, as a precursor in the production of linear low-density polyethylene (LLDPE), and as a growth inhibitor of tobacco plant suckers. Due to the low availability of eight-carbon acyl chains in natural lipid feedstocks and the selectivity challenges in petrochemical routes to medium-chain fatty alcohols,1-octanol sells for the highest price among the fatty alcohol products. As an alternative, metabolic engineers have pursued sustainable 1-octanol production via engineered microbes. Here, we report demonstration of gram per liter titers in the model bacterium Escherichia coli via the development of a pathway composed of a thioesterase, an acyl-CoA synthetase, and an acyl-CoA reductase. In addition, the impact of deleting fermentative pathways was explored E. coli K12 MG1655 strain for production of octanoic acid, a key octanol precursor. In order to overcome metabolic flux barriers, bioprospecting experiments were performed to identify acyl-CoA synthetases with high activity towards octanoic acid and acyl-CoA reductases with high activity to produce 1-octanol from octanoyl-CoA. Titration of expression of key pathway enzymes was performed and a strain with the full pathway integrated on the chromosome was created. The final strain produced 1-octanol at 1.3 g/L titer and a >90% C8 specificity from glycerol. In addition to the metabolic engineering efforts, this work addressed some of the technical challenges that arise when quantifying 1-octanol produced from cultures grown under fully aerobic conditions where evaporation and stripping are prevalent.
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Affiliation(s)
- Néstor J Hernández Lozada
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | - Trevor R Simmons
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | - Ke Xu
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | - Michael A Jindra
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA.
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24
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Velázquez-Sánchez C, Espín G, Peña C, Segura D. The Modification of Regulatory Circuits Involved in the Control of Polyhydroxyalkanoates Metabolism to Improve Their Production. Front Bioeng Biotechnol 2020; 8:386. [PMID: 32426348 PMCID: PMC7204398 DOI: 10.3389/fbioe.2020.00386] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 04/07/2020] [Indexed: 11/13/2022] Open
Abstract
Poly-(3-hydroxyalkanoates) (PHAs) are bacterial carbon and energy storage compounds. These polymers are synthesized under conditions of nutritional imbalance, where a nutrient is growth-limiting while there is still enough carbon source in the medium. On the other side, the accumulated polymer is mobilized under conditions of nutrient accessibility or by limitation of the carbon source. Thus, it is well known that the accumulation of PHAs is affected by the availability of nutritional resources and this knowledge has been used to establish culture conditions favoring high productivities. In addition to this effect of the metabolic status on PHAs accumulation, several genetic regulatory networks have been shown to drive PHAs metabolism, so the expression of the PHAs genes is under the influence of global or specific regulators. These regulators are thought to coordinate PHAs synthesis and mobilization with the rest of bacterial physiology. While the metabolic and biochemical knowledge related to the biosynthesis of these polymers has led to the development of processes in bioreactors for high-level production and also to the establishment of strategies for metabolic engineering for the synthesis of modified biopolymers, the use of knowledge related to the regulatory circuits controlling PHAs metabolism for strain improvement is scarce. A better understanding of the genetic control systems involved could serve as the foundation for new strategies for strain modification in order to increase PHAs production or to adjust the chemical structure of these biopolymers. In this review, the regulatory systems involved in the control of PHAs metabolism are examined, with emphasis on those acting at the level of expression of the enzymes involved and their potential modification for strain improvement, both for higher titers, or manipulation of polymer properties. The case of the PHAs producer Azotobacter vinelandii is taken as an example of the complexity and variety of systems controlling the accumulation of these interesting polymers in response to diverse situations, many of which could be engineered to improve PHAs production.
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Affiliation(s)
- Claudia Velázquez-Sánchez
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Guadalupe Espín
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Carlos Peña
- Departamento Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Daniel Segura
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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25
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Construction of a "nutrition supply-detoxification" coculture consortium for medium-chain-length polyhydroxyalkanoate production with a glucose-xylose mixture. J Ind Microbiol Biotechnol 2020; 47:343-354. [PMID: 32140930 DOI: 10.1007/s10295-020-02267-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 02/23/2020] [Indexed: 10/24/2022]
Abstract
In this study, we constructed a coculture consortium comprising engineered Pseudomonas putida KT2440 and Escherichia coli MG1655. Provision of "related" carbon sources and synthesis of medium-chain-length polyhydroxyalkanoates (mcl-PHAs) were separately assigned to these strains via a modular construction strategy. To avoid growth competition, a preference for the use of a carbon source was constructed. Further, the main intermediate metabolite acetate played an important role in constructing the expected "nutrition supply-detoxification" relationship between these strains. The coculture consortium showed a remarkable increase in the mcl-PHA titer (0.541 g/L) with a glucose-xylose mixture (1:1). Subsequently, the titer of mcl-PHA produced by the coculture consortium when tested with actual lignocellulosic hydrolysate (0.434 g/L) was similar to that achieved with laboratory sugars' mixture (0.469 g/L). These results indicate a competitive potential of the engineered E. coli-P. putida coculture consortium for mcl-PHA production with lignocellulosic hydrolysate.
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26
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Scheel RA, Fusi AD, Min BC, Thomas CM, Ramarao BV, Nomura CT. Increased Production of the Value-Added Biopolymers Poly( R-3-Hydroxyalkanoate) and Poly(γ-Glutamic Acid) From Hydrolyzed Paper Recycling Waste Fines. Front Bioeng Biotechnol 2019; 7:409. [PMID: 31921814 PMCID: PMC6930151 DOI: 10.3389/fbioe.2019.00409] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 11/27/2019] [Indexed: 11/25/2022] Open
Abstract
Reject fines, a waste stream of short lignocellulosic fibers produced from paper linerboard recycling, are a cellulose-rich paper mill byproduct that can be hydrolyzed enzymatically into fermentable sugars. In this study, the use of hydrolyzed reject fines as a carbon source for bacterial biosynthesis of poly(R-3-hydroxyalkanoate) (PHA) and poly(γ-glutamic acid) (PGA) was investigated. Recombinant Escherichia coli harboring PHA biosynthesis genes were cultivated with purified sugars or crude hydrolysate to produce both poly(R-3-hydroxybutyrate) (PHB) homopolymer and medium chain length-containing copolymer (PHB-co-MCL). Wild-type Bacillus licheniformis WX-02 were cultivated with crude hydrolysate to produce PGA. Both PHB and short chain-length-co-medium chain-length (SCL-co-MCL) PHA yields from crude hydrolysate were a 2-fold improvement over purified sugars, and the MCL monomer fraction was decreased slightly in copolymers produced from crude hydrolysate. PGA yield from crude hydrolysate was similarly increased 2-fold. The results suggest that sugars from hydrolyzed reject fines are a viable carbon source for PHA and PGA biosynthesis. The use of crude hydrolysate is not only possible but beneficial for biopolymer production, eliminating the need for costly separation and purification techniques. This study demonstrates the potential to divert a lignocellulosic waste stream into valuable biomaterials, mitigating the environmental impacts of solid waste disposal.
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Affiliation(s)
- Ryan A Scheel
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States
| | - Alexander D Fusi
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States
| | - Byeong C Min
- Department of Paper and Bioprocess Engineering, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States
| | - Christopher M Thomas
- Department of Paper and Bioprocess Engineering, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States
| | - Bandaru V Ramarao
- Department of Paper and Bioprocess Engineering, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States
| | - Christopher T Nomura
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States.,Center for Applied Microbiology, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States
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27
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Możejko-Ciesielska J, Serafim LS. Proteomic Response of Pseudomonas putida KT2440 to Dual Carbon-Phosphorus Limitation during mcl-PHAs Synthesis. Biomolecules 2019; 9:E796. [PMID: 31795154 PMCID: PMC6995625 DOI: 10.3390/biom9120796] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/19/2019] [Accepted: 11/24/2019] [Indexed: 01/01/2023] Open
Abstract
Pseudomonas putida KT2440, one of the best characterized pseudomonads, is a metabolically versatile producer of medium-chain-length polyhydroxyalkanoates (mcl-PHAs) that serves as a model bacterium for molecular studies. The synthesis of mcl-PHAs is of great interest due to their commercial potential. Carbon and phosphorus are the essential nutrients for growth and their limitation can trigger mcl-PHAs' production in microorganisms. However, the specific molecular mechanisms that drive this synthesis in Pseudomonas species under unfavorable growth conditions remain poorly understood. Therefore, the proteomic responses of Pseudomonas putida KT2440 to the limited carbon and phosphorus levels in the different growth phases during mcl-PHAs synthesis were investigated. The data indicated that biopolymers' production was associated with the cell growth of P. putida KT2440 under carbon- and phosphorus-limiting conditions. The protein expression pattern changed during mcl-PHAs synthesis and accumulation, and during the different physiological states of the microorganism. The data suggested that the majority of metabolic activities ceased under carbon and phosphorus limitation. The abundance of polyhydroxyalkanoate granule-associated protein (PhaF) involved in PHA synthesis increased significantly at 24 and 48 h of the cultivations. The activation of proteins belonging to the phosphate regulon was also detected. Moreover, these results indicated changes in the protein profiles related to amino acids metabolism, replication, transcription, translation, stress response mechanisms, transport or signal transduction. The presented data allowed the investigation of time-course proteome alterations in response to carbon and phosphorus limitation, and PHAs synthesis. This study provided information about proteins that can be potential targets in improving the efficiency of mcl-PHAs synthesis.
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Affiliation(s)
- Justyna Możejko-Ciesielska
- Department of Microbiology and Mycology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10719 Olsztyn, Poland
- Chemistry Department, CICECO-Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal;
| | - Luísa S. Serafim
- Chemistry Department, CICECO-Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal;
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28
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Production of Polyhydroxyalkanoates and Extracellular Products Using Pseudomonas Corrugata and P. Mediterranea: A Review. Bioengineering (Basel) 2019; 6:bioengineering6040105. [PMID: 31739507 PMCID: PMC6955742 DOI: 10.3390/bioengineering6040105] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 11/10/2019] [Accepted: 11/12/2019] [Indexed: 11/16/2022] Open
Abstract
Some strains of Pseudomonas corrugata (Pco) and P. mediterranea (Pme) efficiently synthesize medium-chain-length polyhydroxyalkanoates elastomers (mcl-PHA) and extracellular products on related and unrelated carbon sources. Yield and composition are dependent on the strain, carbon source, fermentation process, and any additives. Selected Pco strains produce amorphous and sticky mcl-PHA, whereas strains of Pme produce, on high grade and partially refined biodiesel glycerol, a distinctive filmable PHA, very different from the conventional microbial mcl-PHA, suitable for making blends with polylactide acid. However, the yields still need to be improved and production costs lowered. An integrated process has been developed to recover intracellular mcl-PHA and extracellular bioactive molecules. Transcriptional regulation studies during PHA production contribute to understanding the metabolic potential of Pco and Pme strains. Data available suggest that pha biosynthesis genes and their regulations will be helpful to develop new, integrated strategies for cost-effective production.
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29
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Salvachúa D, Rydzak T, Auwae R, De Capite A, Black BA, Bouvier JT, Cleveland NS, Elmore JR, Huenemann JD, Katahira R, Michener WE, Peterson DJ, Rohrer H, Vardon DR, Beckham GT, Guss AM. Metabolic engineering of Pseudomonas putida for increased polyhydroxyalkanoate production from lignin. Microb Biotechnol 2019; 13:290-298. [PMID: 31468725 PMCID: PMC6922519 DOI: 10.1111/1751-7915.13481] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 08/10/2019] [Indexed: 12/01/2022] Open
Abstract
Microbial conversion offers a promising strategy for overcoming the intrinsic heterogeneity of the plant biopolymer, lignin. Soil microbes that natively harbour aromatic‐catabolic pathways are natural choices for chassis strains, and Pseudomonas putida KT2440 has emerged as a viable whole‐cell biocatalyst for funnelling lignin‐derived compounds to value‐added products, including its native carbon storage product, medium‐chain‐length polyhydroxyalkanoates (mcl‐PHA). In this work, a series of metabolic engineering targets to improve mcl‐PHA production are combined in the P. putida chromosome and evaluated in strains growing in a model aromatic compound, p‐coumaric acid, and in lignin streams. Specifically, the PHA depolymerase gene phaZ was knocked out, and the genes involved in β‐oxidation (fadBA1 and fadBA2) were deleted. Additionally, to increase carbon flux into mcl‐PHA biosynthesis, phaG, alkK, phaC1 and phaC2 were overexpressed. The best performing strain – which contains all the genetic modifications detailed above – demonstrated a 53% and 200% increase in mcl‐PHA titre (g l−1) and a 20% and 100% increase in yield (g mcl‐PHA per g cell dry weight) from p‐coumaric acid and lignin, respectively, compared with the wild type strain. Overall, these results present a promising strain to be employed in further process development for enhancing mcl‐PHA production from aromatic compounds and lignin.
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Affiliation(s)
- Davinia Salvachúa
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Thomas Rydzak
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Raquel Auwae
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Annette De Capite
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Brenna A Black
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Jason T Bouvier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Nicholas S Cleveland
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Joshua R Elmore
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Jay D Huenemann
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Rui Katahira
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - William E Michener
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Darren J Peterson
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Holly Rohrer
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Derek R Vardon
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Gregg T Beckham
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Adam M Guss
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
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30
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Zhuang Q, Qi Q. Engineering the pathway in Escherichia coli for the synthesis of medium-chain-length polyhydroxyalkanoates consisting of both even- and odd-chain monomers. Microb Cell Fact 2019; 18:135. [PMID: 31409350 PMCID: PMC6693092 DOI: 10.1186/s12934-019-1186-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/03/2019] [Indexed: 12/19/2022] Open
Abstract
Background Medium-chain-length polyhydroxyalkanoates (mcl-PHAs) containing various chain length monomers from C6 to C14 have more applications besides sustainable and environmental-friendly biomaterials owing to their superior physical and mechanical properties. We engineered a reversed fatty acid β-oxidation pathway in Escherichia coli that can synthesize mcl-PHA directly from glucose and achieved high yield. However, there were only even-chain monomers in the biosynthetic polymers. The need for mcl-PHA harboring both even- and odd-chain monomers with better and wider utility impels us to develop the biosynthetic routes for the production of the novel and unnatural mcl-PHA through rewiring the basic metabolism. Results In the present study, a propionate assimilation and metabolic route was integrated into the reversed fatty acid β-oxidation in order to produce mcl-PHA consisting of both even- and odd-numbered monomers. The content of odd-numbered monomers in mcl-PHA was improved with the increased propionate addition. After further deletion of pyruvate oxidase (PoxB) and pyruvate formate-lyase (PflB), the metabolically engineered chassis E. coli LZ08 harboring pQQ05 and pZQ06 (overexpression of prpP and prpE genes from Ralstonia eutropha H16) innovatively accumulated 6.23 wt% mcl-PHA containing odd-chain monomers ranging from 7 to 13 carbon atoms about 20.03 mol%. Conclusions This is the first successful report on production of mcl-PHA harboring both even- and odd-chain monomers (C6–C14) synthesized from glucose and propionate in recombinant E. coli. This present study achieved the highest yield of de novo production of mcl-PHA containing odd-numbered monomers in E. coli at shake-flask fermentation level. Continued engineering of host strains and pathway enzymes will ultimately lead to more economical production of odd-chain monomers based on market demand. The synthetic pathway can provide a promising platform for production of other value-added chemicals and biomaterials that use acetyl-CoA and propionyl-CoA as versatile precursors and can be extended to other microorganisms as intelligent cell factories. Electronic supplementary material The online version of this article (10.1186/s12934-019-1186-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Qianqian Zhuang
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, People's Republic of China. .,Shandong Provincial Key Laboratory of Microbial Engineering, School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, People's Republic of China.
| | - Qingsheng Qi
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
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31
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Biosynthesis of novel lactate-based polymers containing medium-chain-length 3-hydroxyalkanoates by recombinant Escherichia coli strains from glucose. J Biosci Bioeng 2019; 128:191-197. [DOI: 10.1016/j.jbiosc.2019.01.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 01/10/2019] [Accepted: 01/15/2019] [Indexed: 11/22/2022]
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32
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Uribe Acosta M, Villa Restrepo AF. In silico analysis of phag-like protein in Ralstonia Euthropa H16, potentially involved in polyhydroxyalkanoates synthesis. REVISTA POLITÉCNICA 2019. [DOI: 10.33571/rpolitec.v15n29a5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Polyhydroxyalkanoates (PHA) are synthesised by bacteria as carbon storage material. The protein PhaG directs carbon from non-related carbon sources such as glycerol, metabolised through fatty acid de novo synthesis (FAS) pathway, with PHA synthesis. The gene that codifies for this protein has not yet been found in the genome of Ralstonia eutropha H16, a model organism. By bioinformatic comparison to already known PhaG proteins, a PhaG-like protein was found codified by gene H16_A0147 and presence of the gene was preliminary confirmed by PCR. This is the first study that shows the presence and characteristics of a PhaG-like protein in R. eutropha H16 and represents the first step for the identification of a connection between FAS and PHA pathways in this model bacterium. Further gene deletion and enzymatic activity studies are necessary to confirm this potential relationship, which could improve industrial PHA production and utilisation of agro-industrial residues such as glycerol.
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33
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Yang S, Li S, Jia X. Production of medium chain length polyhydroxyalkanoate from acetate by engineered Pseudomonas putida KT2440. ACTA ACUST UNITED AC 2019; 46:793-800. [DOI: 10.1007/s10295-019-02159-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 03/05/2019] [Indexed: 11/27/2022]
Abstract
Abstract
Pseudomonas putida was metabolically engineered to produce medium chain length polyhydroxyalkanoate (mcl-PHA) from acetate, a promising carbon source to achieve cost-effective microbial processes. As acetate is known to be harmful to cell growth, P. putida KT2440 was screened from three Pseudomonas strains (P. putida KT2440, P. putida NBRC14164, and P. aeruginosa PH1) as the host with the highest tolerance to 10 g/L of acetate in the medium. Subsequently, P. putida KT2440 was engineered by amplifying the acetate assimilation pathway, including overexpression of the acs (encoding acetyl-CoA synthetase) route and construction of the ackA-pta (encoding acetate kinase-phosphotransacetylase) pathway. The acs overexpressing P. putida KT2440 showed a remarkable increase of mcl-PHA titer (+ 92%), mcl-PHA yield (+ 50%), and cellular mcl-PHA content (+ 43%) compared with the wild-type P. putida KT2440, which indicated that acetate could be a potential substrate for biochemical production of mcl-PHA by engineered P. putida.
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Affiliation(s)
- Songyuan Yang
- 0000 0004 1761 2484 grid.33763.32 Department of Biological Engineering, School of Chemical Engineering and Technology Tianjin University 300072 Tianjin People’s Republic of China
- 0000 0004 1761 2484 grid.33763.32 Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology Tianjin University 300350 Tianjin People’s Republic of China
| | - Suhang Li
- 0000 0004 1761 2484 grid.33763.32 Department of Biological Engineering, School of Chemical Engineering and Technology Tianjin University 300072 Tianjin People’s Republic of China
- 0000 0004 1761 2484 grid.33763.32 Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology Tianjin University 300350 Tianjin People’s Republic of China
| | - Xiaoqiang Jia
- 0000 0004 1761 2484 grid.33763.32 Department of Biological Engineering, School of Chemical Engineering and Technology Tianjin University 300072 Tianjin People’s Republic of China
- 0000 0004 1761 2484 grid.33763.32 Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology Tianjin University 300350 Tianjin People’s Republic of China
- 0000 0004 1761 2484 grid.33763.32 Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) 300072 Tianjin People’s Republic of China
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34
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Lakshmanan M, Foong CP, Abe H, Sudesh K. Biosynthesis and characterization of co and ter-polyesters of polyhydroxyalkanoates containing high monomeric fractions of 4-hydroxybutyrate and 5-hydroxyvalerate via a novel PHA synthase. Polym Degrad Stab 2019. [DOI: 10.1016/j.polymdegradstab.2019.03.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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35
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Zhao F, Liu X, Kong A, Zhao Y, Fan X, Ma T, Gao W, Wang S, Yang C. Screening of endogenous strong promoters for enhanced production of medium-chain-length polyhydroxyalkanoates in Pseudomonas mendocina NK-01. Sci Rep 2019; 9:1798. [PMID: 30755729 PMCID: PMC6372614 DOI: 10.1038/s41598-019-39321-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 01/21/2019] [Indexed: 01/02/2023] Open
Abstract
Polyhydroxyalkanoate (PHA) can be produced by microorganisms from renewable resources and is regarded as a promising bioplastic to replace petroleum-based plastics. Pseudomonas mendocina NK-01 is a medium-chain-length PHA (mcl-PHA)-producing strain and its whole-genome sequence is currently available. The yield of mcl-PHA in P. mendocina NK-01 is expected to be improved by applying a promoter engineering strategy. However, a limited number of well-characterized promoters has greatly restricted the application of promoter engineering for increasing the yield of mcl-PHA in P. mendocina NK-01. In this work, 10 endogenous promoters from P. mendocina NK-01 were identified based on RNA-seq and promoter prediction results. Subsequently, 10 putative promoters were characterized for their strength through the expression of a reporter gene gfp. As a result, five strong promoters designated as P4, P6, P9, P16 and P25 were identified based on transcriptional level and GFP fluorescence intensity measurements. To evaluate whether the screened promoters can be used to enhance transcription of PHA synthase gene (phaC), the three promoters P4, P6 and P16 were separately integrated into upstream of the phaC operon in the genome of P. mendocina NK-01, resulting in the recombinant strains NKU-4C1, NKU-6C1 and NKU-16C1. As expected, the transcriptional levels of phaC1 and phaC2 in the recombinant strains were increased as shown by real-time quantitative RT-PCR. The phaZ gene encoding PHA depolymerase was further deleted to construct the recombinant strains NKU-∆phaZ-4C1, NKU-∆phaZ-6C1 and NKU-∆phaZ-16C1. The results from shake-flask fermentation indicated that the mcl-PHA titer of recombinant strain NKU-∆phaZ-16C1 was increased from 17 to 23 wt% compared with strain NKU-∆phaZ. This work provides a feasible method to discover strong promoters in P. mendocina NK-01 and highlights the potential of the screened endogenous strong promoters for metabolic engineering of P. mendocina NK-01 to increase the yield of mcl-PHA.
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Affiliation(s)
- Fengjie Zhao
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China
| | - Xiangsheng Liu
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China
| | - Annie Kong
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China
| | - Yuxin Zhao
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China
| | - Xu Fan
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China
| | - Ting Ma
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China
| | - Weixia Gao
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300071, China.
| | - Shufang Wang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300071, China.
| | - Chao Yang
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China.
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Kandasamy R, Rajasekaran M, Venkatesan SK, Uddin M. New Trends in the Biomanufacturing of Green Surfactants: Biobased Surfactants and Biosurfactants. ACS SYMPOSIUM SERIES 2019. [DOI: 10.1021/bk-2019-1329.ch011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Ramani Kandasamy
- Biomolecules and Biocatalysis Laboratory, Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur 603 203, Tamil Nadu, India
| | - Muneeswari Rajasekaran
- Biomolecules and Biocatalysis Laboratory, Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur 603 203, Tamil Nadu, India
| | - Swathi Krishnan Venkatesan
- Biomolecules and Biocatalysis Laboratory, Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur 603 203, Tamil Nadu, India
| | - Maseed Uddin
- Biomolecules and Biocatalysis Laboratory, Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur 603 203, Tamil Nadu, India
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Samantaray PK, Madras G, Bose S. Microbial Biofilm Membranes for Water Remediation and Photobiocatalysis. ACS SYMPOSIUM SERIES 2019. [DOI: 10.1021/bk-2019-1329.ch014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Paresh Kumar Samantaray
- Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
- Department of Materials Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Giridhar Madras
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Suryasarathi Bose
- Department of Materials Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
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Yadav TC, Srivastava AK, Mishra P, Singh D, Raghuwanshi N, Singh NK, Singh AK, Tiwari SK, Prasad R, Pruthi V. Electrospinning: An Efficient Biopolymer-Based Micro- and Nanofibers Fabrication Technique. ACS SYMPOSIUM SERIES 2019. [DOI: 10.1021/bk-2019-1329.ch010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Tara Chand Yadav
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee - 247667, Uttarakhand, India
| | - Amit Kumar Srivastava
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee - 247667, Uttarakhand, India
| | - Purusottam Mishra
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee - 247667, Uttarakhand, India
| | - Divya Singh
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee - 247667, Uttarakhand, India
| | - Navdeep Raghuwanshi
- Vaccine Formulation & Research Center, Gennova (Emcure) Biopharmaceuticals Limited, Pune - 411057, Maharashtra, India
| | - Nitin Kumar Singh
- Department of Environment Science and Engineering, Marwadi Education Foundations Group of Institutions, Rajkot - 360003, Gujarat, India
| | - Amit Kumar Singh
- Department of Biochemistry, University of Allahabad, Allahabad, 211002 India
| | | | - Ramasare Prasad
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee - 247667, Uttarakhand, India
| | - Vikas Pruthi
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee - 247667, Uttarakhand, India
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Li M, Chen X, Che X, Zhang H, Wu LP, Du H, Chen GQ. Engineering Pseudomonas entomophila for synthesis of copolymers with defined fractions of 3-hydroxybutyrate and medium-chain-length 3-hydroxyalkanoates. Metab Eng 2018; 52:253-262. [PMID: 30582985 DOI: 10.1016/j.ymben.2018.12.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 12/19/2018] [Accepted: 12/20/2018] [Indexed: 01/06/2023]
Abstract
Polyhydroxyalkanoates (PHA) composed of both short-chain-length (SCL) and medium-chain-length (MCL) monomers (SCL-co-MCL PHA) combine the advantages of high strength and elasticity provided by SCL PHA and MCL PHA, respectively. Synthesis of SCL-co-MCL PHA, namely, copolymers of 3-hydroxybutyrate (3HB) and MCL 3-hydroxyalkanoates (3HA) such as 3-hydroxydecanoate (3HD) and longer chain 3HA, has been a challenge for a long time. This study aims to engineer Pseudomonas entomophila for synthesizing P(3HB-co-MCL 3HA) via weakening its β-oxidation pathway combined with insertion of 3HB synthesis pathway consisting of β-ketothiolase (phaA) and acetoacetyl-CoA reductase (phaB). 3HB and MCL 3HA polymerization is catalyzed by a low specificity PHA synthase (phaC), namely, mutated PhaC61-3. The link between the fatty acid de novo synthesis and PHA synthesis was further blocked to increase the supply for SCL and MCL monomers in P. entomophila. The so-constructed P. entomophila was successfully used to synthesize novel PHA copolymers of P(3HB-co-3HD), P(3HB-co-3HDD) and P(3HB-co-3H9D) consisting of 3HB and 3-hydroxydecanoate (3HD), 3-hydroxydodecanoate (3HDD) and 3-hydroxy-9-decanent (3H9D), respectively. MCL 3HA compositions of P(3HB-co-3HD) and P(3HB-co-3HDD) can be adjusted from 0 to approximate 100 mol%. Results demonstrated that the engineered P. entomophila could be a platform for tailor-made P(3HB-co-MCL 3HA).
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Affiliation(s)
- Mengyi Li
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiangbin Chen
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xuemei Che
- Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; Center for Nano- and Micro-Mechanics, Tsinghua University, Beijing 100084, China
| | | | - Lin-Ping Wu
- Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China
| | - Hetong Du
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Guo-Qiang Chen
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China; School of Life Sciences, Tsinghua University, Beijing 100084, China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; Center for Nano- and Micro-Mechanics, Tsinghua University, Beijing 100084, China.
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Butt FI, Muhammad N, Hamid A, Moniruzzaman M, Sharif F. Recent progress in the utilization of biosynthesized polyhydroxyalkanoates for biomedical applications – Review. Int J Biol Macromol 2018; 120:1294-1305. [DOI: 10.1016/j.ijbiomac.2018.09.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 07/20/2018] [Accepted: 09/02/2018] [Indexed: 01/10/2023]
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Simultaneous Improvements of Pseudomonas Cell Growth and Polyhydroxyalkanoate Production from a Lignin Derivative for Lignin-Consolidated Bioprocessing. Appl Environ Microbiol 2018; 84:AEM.01469-18. [PMID: 30030226 DOI: 10.1128/aem.01469-18] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 07/05/2018] [Indexed: 11/20/2022] Open
Abstract
Cell growth and polyhydroxyalkanoate (PHA) biosynthesis are two key traits in PHA production from lignin or its derivatives. However, the links between them remain poorly understood. Here, the transcription levels of key genes involved in PHA biosynthesis were tracked in Pseudomonas putida strain A514 grown on vanillic acid as the sole carbon source under different levels of nutrient availability. First, enoyl-coenzyme A (CoA) hydratase (encoded by phaJ4) is stress induced and likely to contribute to PHA synthesis under nitrogen starvation conditions. Second, much higher expression levels of 3-hydroxyacyl-acyl carrier protein (ACP) thioesterase (encoded by phaG) and long-chain fatty acid-CoA ligase (encoded by alkK) under both high and low nitrogen (N) led to the hypothesis that they likely not only have a role in PHA biosynthesis but are also essential to cell growth. Third, 40 mg/liter PHA was synthesized by strain AphaJ4C1 (overexpression of phaJ4 and phaC1 in strain A514) under low-N conditions, in contrast to 23 mg/liter PHA synthesized under high-N conditions. Under high-N conditions, strain AalkKphaGC1 (overexpression of phaG, alkK, and phaC1 in A514) produced 90 mg/liter PHA with a cell dry weight of 667 mg/liter, experimentally validating our hypothesis. Finally, further enhancement in cell growth (714 mg/liter) and PHA titer (246 mg/liter) was achieved in strain Axyl_alkKphaGC1 via transcription level optimization, which was regulated by an inducible strong promoter with its regulator, XylR-PxylA, from the xylose catabolic gene cluster of the A514 genome. This study reveals genetic features of genes involved in PHA synthesis from a lignin derivative and provides a novel strategy for rational engineering of these two traits, laying the foundation for lignin-consolidated bioprocessing.IMPORTANCE With the recent advances in processing carbohydrates in lignocellulosics for bioproducts, almost all biological conversion platforms result in the formation of a significant amount of lignin by-products, representing the second most abundant feedstock on earth. However, this resource is greatly underutilized due to its heterogeneity and recalcitrant chemical structure. Thus, exploiting lignin valorization routes would achieve the complete utilization of lignocellulosic biomass and improve cost-effectiveness. The culture conditions that encourage cell growth and polyhydroxyalkanoate (PHA) accumulation are different. Such an inconsistency represents a major hurdle in lignin-to-PHA bioconversion. In this study, we traced and compared transcription levels of key genes involved in PHA biosynthesis pathways in Pseudomonas putida A514 under different nitrogen concentrations to unveil the unusual features of PHA synthesis. Furthermore, an inducible strong promoter was identified. Thus, the molecular features and new genetic tools reveal a strategy to coenhance PHA production and cell growth from a lignin derivative.
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Funston SJ, Tsaousi K, Smyth TJ, Twigg MS, Marchant R, Banat IM. Enhanced rhamnolipid production in Burkholderia thailandensis transposon knockout strains deficient in polyhydroxyalkanoate (PHA) synthesis. Appl Microbiol Biotechnol 2017; 101:8443-8454. [PMID: 29043376 PMCID: PMC5694511 DOI: 10.1007/s00253-017-8540-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 08/28/2017] [Accepted: 09/08/2017] [Indexed: 11/29/2022]
Abstract
Microbially produced rhamnolipids have significant commercial potential; however, the main bacterial producer, Pseudomonas aeruginosa, is an opportunistic human pathogen, which limits biotechnological exploitation. The non-pathogenic species Burkholderia thailandensis produces rhamnolipids; however, yield is relatively low. The aim of this study was to determine whether rhamnolipid production could be increased in Burkholderia thailandensis through mutation of genes responsible for the synthesis of the storage material polyhydroxyalkanoate (PHA), thereby increasing cellular resources for the production of rhamnolipids. Potential PHA target genes were identified in B. thailandensis through comparison with known function genes in Pseudomonas aeruginosa. Multiple knockout strains for the phbA, phbB and phbC genes were obtained and their growth characteristics and rhamnolipid and PHA production determined. The wild-type strain and an rhamnolipid (RL)-deficient strain were used as controls. Three knockout strains (ΔphbA1, ΔphbB1 and ΔphbC1) with the best enhancement of rhamnolipid production were selected for detailed study. ΔphbB1 produced the highest level of purified RL (3.78 g l−1) compared to the wild-type strain (1.28 g l−1). In ΔphbB1, the proportion of mono-rhamnolipid was also increased compared to the wild-type strain. The production of PHA was reduced by at least 80% in all three phb mutant strains, although never completely eliminated. These results suggest that, in contrast to Pseudomonas aeruginosa, knockout of the PHA synthesis pathway in Burkholderia thailandensis could be used to increase rhamnolipid production. The evidence of residual PHA production in the phb mutant strains suggests B. thailandensis possesses a secondary unelucidated PHA synthesis pathway.
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Affiliation(s)
- Scott J Funston
- School of Biomedical Sciences, Ulster University, BT521SA, Coleraine, Northern Ireland, UK
| | - Konstantina Tsaousi
- School of Biomedical Sciences, Ulster University, BT521SA, Coleraine, Northern Ireland, UK
| | - Thomas J Smyth
- Department of Life Sciences, Institute of Technology Sligo, Sligo, County Sligo, Ireland
| | - Matthew S Twigg
- School of Biomedical Sciences, Ulster University, BT521SA, Coleraine, Northern Ireland, UK
| | - Roger Marchant
- School of Biomedical Sciences, Ulster University, BT521SA, Coleraine, Northern Ireland, UK
| | - Ibrahim M Banat
- School of Biomedical Sciences, Ulster University, BT521SA, Coleraine, Northern Ireland, UK.
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Synthesis Gas (Syngas)-Derived Medium-Chain-Length Polyhydroxyalkanoate Synthesis in Engineered Rhodospirillum rubrum. Appl Environ Microbiol 2016; 82:6132-6140. [PMID: 27520812 DOI: 10.1128/aem.01744-16] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 07/22/2016] [Indexed: 11/20/2022] Open
Abstract
The purple nonsulfur alphaproteobacterium Rhodospirillum rubrum S1 was genetically engineered to synthesize a heteropolymer of mainly 3-hydroxydecanoic acid and 3-hydroxyoctanoic acid [P(3HD-co-3HO)] from CO- and CO2-containing artificial synthesis gas (syngas). For this, genes from Pseudomonas putida KT2440 coding for a 3-hydroxyacyl acyl carrier protein (ACP) thioesterase (phaG), a medium-chain-length (MCL) fatty acid coenzyme A (CoA) ligase (PP_0763), and an MCL polyhydroxyalkanoate (PHA) synthase (phaC1) were cloned and expressed under the control of the CO-inducible promoter PcooF from R. rubrum S1 in a PHA-negative mutant of R. rubrum P(3HD-co-3HO) was accumulated to up to 7.1% (wt/wt) of the cell dry weight by a recombinant mutant strain utilizing exclusively the provided gaseous feedstock syngas. In addition to an increased synthesis of these medium-chain-length PHAs (PHAMCL), enhanced gene expression through the PcooF promoter also led to an increased molar fraction of 3HO in the synthesized copolymer compared with the Plac promoter, which regulated expression on the original vector. The recombinant strains were able to partially degrade the polymer, and the deletion of phaZ2, which codes for a PHA depolymerase most likely involved in intracellular PHA degradation, did not reduce mobilization of the accumulated polymer significantly. However, an amino acid exchange in the active site of PhaZ2 led to a slight increase in PHAMCL accumulation. The accumulated polymer was isolated; it exhibited a molecular mass of 124.3 kDa and a melting point of 49.6°C. With the metabolically engineered strains presented in this proof-of-principle study, we demonstrated the synthesis of elastomeric second-generation biopolymers from renewable feedstocks not competing with human nutrition. IMPORTANCE Polyhydroxyalkanoates (PHAs) are natural biodegradable polymers (biopolymers) showing properties similar to those of commonly produced petroleum-based nondegradable polymers. The utilization of cheap substrates for the microbial production of PHAs is crucial to lower production costs. Feedstock not competing with human nutrition is highly favorable. Syngas, a mixture of carbon monoxide, carbon dioxide, and hydrogen, can be obtained by pyrolysis of organic waste and can be utilized for PHA synthesis by several kinds of bacteria. Up to now, the biosynthesis of PHAs from syngas has been limited to short-chain-length PHAs, which results in a stiff and brittle material. In this study, the syngas-utilizing bacterium Rhodospirillum rubrum was genetically modified to synthesize a polymer which consisted of medium-chain-length constituents, resulting in a rubber-like material. This study reports the establishment of a microbial synthesis of these so-called medium-chain-length PHAs from syngas and therefore potentially extends the applications of syngas-derived PHAs.
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Bacterial polyhydroxyalkanoates: Still fabulous? Microbiol Res 2016; 192:271-282. [PMID: 27664746 DOI: 10.1016/j.micres.2016.07.010] [Citation(s) in RCA: 173] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Revised: 07/19/2016] [Accepted: 07/28/2016] [Indexed: 01/07/2023]
Abstract
Bacterial polyhydroxyalkanoates (PHA) are polyesters accumulated as carbon and energy storage materials under limited growth conditions in the presence of excess carbon sources. They have been developed as biomaterials with unique properties for the past many years being considered as a potential substitute for conventional non-degradable plastics. Due to the increasing concern towards global climate change, depleting petroleum resource and problems with an utilization of a growing number of synthetic plastics, PHAs have gained much more attention from industry and research. These environmentally friendly microbial polymers have great potential in biomedical, agricultural, and industrial applications. However, their production on a large scale is still limited. This paper describes the backgrounds of PHAs and discussed the current state of knowledge on the polyhydroxyalkanoates. Ability of bacteria to convert different carbon sources to PHAs, the opportunities and challenges of their introduction to global market as valuable renewable products have been also discussed.
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Chen GQ, Hajnal I, Wu H, Lv L, Ye J. Engineering Biosynthesis Mechanisms for Diversifying Polyhydroxyalkanoates. Trends Biotechnol 2016; 33:565-574. [PMID: 26409776 DOI: 10.1016/j.tibtech.2015.07.007] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 07/24/2015] [Accepted: 07/30/2015] [Indexed: 11/15/2022]
Abstract
Polyhydroxyalkanoates (PHA) are a family of diverse biopolyesters synthesized by bacteria. PHA diversity, as reflected by its monomers, homopolymers, random and block copolymers, as well as functional polymers, can now be generated by engineering the three basic synthesis pathways including the acetoacetyl-CoA pathway, in situ fatty acid synthesis, and/or β-oxidation cycles, as well as PHA synthase specificity. It is now possible to tailor the PHA structures via genome editing or process engineering. The increasing PHA diversity and maturing PHA production technology should lead to more focused research into their low-cost and/or high-value applications.
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Affiliation(s)
- Guo-Qiang Chen
- Ministry of Education Key Lab of Bioinformatics, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China; Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China; Beijing Key Laboratory of Protein Therapeutics, Tsinghua University, Beijing 100084, China.
| | - Ivan Hajnal
- Ministry of Education Key Lab of Bioinformatics, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Hong Wu
- Ministry of Education Key Lab of Bioinformatics, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Li Lv
- Ministry of Education Key Lab of Bioinformatics, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jianwen Ye
- Ministry of Education Key Lab of Bioinformatics, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China
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Fu J, Sharma P, Spicer V, Krokhin OV, Zhang X, Fristensky B, Cicek N, Sparling R, Levin DB. Quantitative 'Omics Analyses of Medium Chain Length Polyhydroxyalkanaote Metabolism in Pseudomonas putida LS46 Cultured with Waste Glycerol and Waste Fatty Acids. PLoS One 2015; 10:e0142322. [PMID: 26544181 PMCID: PMC4636370 DOI: 10.1371/journal.pone.0142322] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 10/19/2015] [Indexed: 12/19/2022] Open
Abstract
Transcriptomes and proteomes of Pseudomonas putida LS46 cultured with biodiesel-derived waste glycerol or waste free fatty acids, as sole carbon sources, were compared under conditions that were either permissive or non-permissive for synthesis of medium chain length polyhydroxyalkanoates (mcl-PHA). The objectives of this study were to elucidate mechanisms that influence activation of biopolymer synthesis, intra-cellular accumulation, and monomer composition, and determine if these were physiologically specific to the carbon sources used for growth of P. putida LS46. Active mcl-PHA synthesis by P. putida LS46 was associated with high expression levels of key mcl-PHA biosynthesis genes and/or gene products including monomer-supplying proteins, PHA synthases, and granule-associated proteins. 'Omics data suggested that expression of these genes were regulated by different genetic mechanisms in P. putida LS46 cells in different physiological states, when cultured on the two waste carbon sources. Optimal polymer production by P. putida LS46 was primarily limited by less efficient glycerol metabolism during mcl-PHA synthesis on waste glycerol. Mapping the 'Omics data to the mcl-PHA biosynthetic pathway revealed significant variations in gene expression, primarily involved in: 1) glycerol transportation; 2) enzymatic reactions that recycle reducing equivalents and produce key mcl-PHA biosynthesis pathway intermediates (e.g. NADH/NADPH, acetyl-CoA). Active synthesis of mcl-PHAs was observed during exponential phase in cultures with waste free fatty acids, and was associated with the fatty acid beta-oxidation pathway. A putative Thioesterase in the beta-oxidation pathway that may regulate the level of fatty acid beta-oxidation intermediates, and thus carbon flux to mcl-PHA biosynthesis, was highly up-regulated. Finally, the data suggested that differences in expression of selected fatty acid metabolism and mcl-PHA monomer-supplying enzymes may play a role in determining the monomer composition of mcl-PHA polymers. Understanding the relationships between genome content, gene and gene product expression, and how these factors influence polymer synthesis, will aid in optimization of mcl-PHA production by P. putida LS46 using biodiesel waste streams.
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Affiliation(s)
- Jilagamazhi Fu
- Department of Biosystem Engineering, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Parveen Sharma
- Department of Biosystem Engineering, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Vic Spicer
- Department of Internal Medicine & Manitoba Centre for Proteomics and Systems Biology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Oleg V. Krokhin
- Department of Internal Medicine & Manitoba Centre for Proteomics and Systems Biology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Xiangli Zhang
- Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Brian Fristensky
- Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Nazim Cicek
- Department of Biosystem Engineering, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Richard Sparling
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - David. B. Levin
- Department of Biosystem Engineering, University of Manitoba, Winnipeg, Manitoba, Canada
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Wang Y, Zhao F, Fan X, Wang S, Song C. Enhancement of medium-chain-length polyhydroxyalkanoates biosynthesis from glucose by metabolic engineering in Pseudomonas mendocina. Biotechnol Lett 2015; 38:313-20. [DOI: 10.1007/s10529-015-1980-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 10/13/2015] [Indexed: 11/24/2022]
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48
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Vastano M, Casillo A, Corsaro MM, Sannia G, Pezzella C. Production of medium chain length polyhydroxyalkanoates from waste oils by recombinantEscherichia coli. Eng Life Sci 2015. [DOI: 10.1002/elsc.201500022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Marco Vastano
- Dipartimento di Scienze Chimiche; Complesso Universitario Monte S. Angelo; Napoli Italy
| | - Angela Casillo
- Dipartimento di Scienze Chimiche; Complesso Universitario Monte S. Angelo; Napoli Italy
| | - Maria Michela Corsaro
- Dipartimento di Scienze Chimiche; Complesso Universitario Monte S. Angelo; Napoli Italy
| | - Giovanni Sannia
- Dipartimento di Scienze Chimiche; Complesso Universitario Monte S. Angelo; Napoli Italy
| | - Cinzia Pezzella
- Dipartimento di Scienze Chimiche; Complesso Universitario Monte S. Angelo; Napoli Italy
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Gao C, Qi Q, Madzak C, Lin CSK. Exploring medium-chain-length polyhydroxyalkanoates production in the engineered yeast Yarrowia lipolytica. J Ind Microbiol Biotechnol 2015; 42:1255-62. [PMID: 26153503 DOI: 10.1007/s10295-015-1649-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 06/23/2015] [Indexed: 11/29/2022]
Abstract
Medium-chain-length polyhydroxyalkanoates (mcl-PHAs) are a large class of biopolymers that have attracted extensive attention as renewable and biodegradable bio-plastics. They are naturally synthesized via fatty acid de novo biosynthesis pathway or β-oxidation pathway from Pseudomonads. The unconventional yeast Yarrowia lipolytica has excellent lipid/fatty acid catabolism and anabolism capacity depending of the mode of culture. Nevertheless, it cannot naturally synthesize PHA, as it does not express an intrinsic PHA synthase. Here, we constructed a genetically modified strain of Y. lipolytica by heterologously expressing PhaC1 gene from P. aeruginosa PAO1 with a PTS1 peroxisomal signal. When in single copy, the codon optimized PhaC1 allowed the synthesis of 0.205 % DCW of PHA after 72 h cultivation in YNBD medium containing 0.1 % oleic acid. By using a multi-copy integration strategy, PHA content increased to 2.84 % DCW when the concentration of oleic acid in YNBD was 1.0 %. Furthermore, when the recombinant yeast was grown in the medium containing triolein, PHA accumulated up to 5.0 % DCW with as high as 21.9 g/L DCW, which represented 1.11 g/L in the culture. Our results demonstrated the potential use of Y. lipolytica as a promising microbial cell factory for PHA production using food waste, which contains lipids and other essential nutrients.
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Affiliation(s)
- Cuijuan Gao
- School of Life Science, Linyi University, Linyi, 276005, People's Republic of China
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Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyalkanoates) by recombinant Escherichia coli from glucose. J Biosci Bioeng 2015; 120:305-10. [PMID: 25732207 DOI: 10.1016/j.jbiosc.2015.01.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 01/28/2015] [Accepted: 01/29/2015] [Indexed: 11/23/2022]
Abstract
The polyhydroxyalkanoate (PHA) copolymers consisting of short-chain-length (scl) and medium-chain-length (mcl) monomers have various properties ranging from stiff to flexible depending on the molar fraction of the monomer compositions. It has been reported that PhaG, which is first known as a (R)-3-hydroxyacyl-acyl carrier protein (ACP)-CoA transferase, actually functions as a 3-hydroxyacyl-ACP thioesterase, and the product of PP0763 gene from Pseudomonas putida KT2440 has a (R)-3-hydroxyacyl (3HA)-CoA ligase activity (Wang et al., Appl. Environ. Microbiol., 78, 519-527, 2012). In this study, we found a new (R)-3HA-CoA ligase (the product of PA3924 gene) from Pseudomonas aeruginosa PAO. The PA3924 gene was coexpressed with PHA synthase 1 gene (phaC1Ps) and phaGPs gene from Pseudomonas sp. 61-3, and β-ketothiolase gene (phbARe) and acetoacetyl-CoA reductase gene (phbBRe) from Ralstonia eutropha in Escherichia coli LS5218 at 25°C. As a result, the copolymer containing 94.6 mol% 3-hydroxybutyrate (3HB) and 5.4 mol% mcl-3-hydroxyalkanoates (3HA) consisting of C8, C10, C12 and C14 was synthesized by recombinant E. coli LS5218 from glucose as the sole carbon source. The concentration of P(3HB-co-3HA) (scl-co-mcl-PHA) synthesized by the recombinant E. coli LS5218 harboring phaC1Ps, phaGPs, phbABRe and the PA3924 genes was approximately 7-fold higher than that of the recombinant LS5218 harboring phaC1Ps, phaGPs, phbABRe and the PP0763 genes. The number-average molecular weight of the P(3HB-co-5.4% 3HA) copolymer was 233 × 10(3), which was relatively high molecular weight. In addition, the physical and the mechanical properties of the copolymer were demonstrated to improve the brittleness of P(3HB) homopolymer.
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