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Costa P, Basaglia M, Casella S, Favaro L. Copolymers as a turning point for large scale polyhydroxyalkanoates applications. Int J Biol Macromol 2024; 275:133575. [PMID: 38960239 DOI: 10.1016/j.ijbiomac.2024.133575] [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: 01/20/2024] [Revised: 05/28/2024] [Accepted: 06/28/2024] [Indexed: 07/05/2024]
Abstract
Traditional plastics reshaped the society thanks to their brilliant properties and cut-price manufacturing costs. However, their protracted durability and limited recycling threaten the environment. Worthy alternatives seem to be polyhydroxyalkanoates, compostable biopolymers produced by several microbes. The most common 3-hydroxybutyrate homopolymer has limited applications calling for copolymers biosynthesis to enhance material properties. As a growing number of researches assess the discovery of novel comonomers, great endeavors are dedicated as well to copolymers production scale-up, where the choice of the microbial carbon source significantly affects the overall economic feasibility. Diving into novel metabolic pathways, engineered strains, and cutting-edge bioprocess strategies, this review aims to survey up-to-date publications about copolymers production, focusing primarily on precursors origins. Specifically, in the core of the review, copolymers precursors have been divided into three categories based on their economic value: the costliest structurally related ones, the structurally unrelated ones, and finally various low-cost waste streams. The combination of cheap biomasses, efficient pretreatment strategies, and robust microorganisms paths the way towards the development of versatile and circular polymers. Conceived to researchers and industries interested in tackling polyhydroxyalkanoates production, this review explores an angle often underestimated yet of prime importance: if PHAs copolymers offer advanced properties and sustainable end-of-life, the feedstock choice for their upstream becomes a major factor in the development of plastic substitutes.
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Affiliation(s)
- Paolo Costa
- Waste-to-Bioproducts Lab, Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, Agripolis, Viale dell'Università, 16, 35020 Legnaro, PD, Italy.
| | - Marina Basaglia
- Waste-to-Bioproducts Lab, Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, Agripolis, Viale dell'Università, 16, 35020 Legnaro, PD, Italy.
| | - Sergio Casella
- Waste-to-Bioproducts Lab, Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, Agripolis, Viale dell'Università, 16, 35020 Legnaro, PD, Italy.
| | - Lorenzo Favaro
- Waste-to-Bioproducts Lab, Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, Agripolis, Viale dell'Università, 16, 35020 Legnaro, PD, Italy; Department of Microbiology, Stellenbosch University, Private Bag X1, 7602 Matieland, South Africa.
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Deng RX, Li HL, Wang W, Hu HB, Zhang XH. Engineering Pseudomonas chlororaphis HT66 for the Biosynthesis of Copolymers Containing 3-Hydroxybutyrate and Medium-Chain-Length 3-Hydroxyalkanoates. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:8684-8692. [PMID: 38564621 DOI: 10.1021/acs.jafc.4c00777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Polyhydroxyalkanoates (PHAs) are promising alternatives to petroleum-based plastics, owing to their biodegradability and superior material properties. Here, the controllable biosynthesis of scl-co-mcl PHA containing 3-hydroxybutyrate (3HB) and mcl 3-hydroxyalkanoates was achieved in Pseudomonas chlororaphis HT66. First, key genes involved in fatty acid β-oxidation, the de novo fatty acid biosynthesis pathway, and the phaC1-phaZ-phaC2 operon were deleted to develop a chassis strain. Subsequently, an acetoacetyl-CoA reductase gene phaB and a PHA synthase gene phaC with broad substrate specificity were heterologously expressed for producing and polymerizing the 3HB monomer with mcl 3-hydroxyalkanoates under the assistance of native β-ketothiolase gene phaA. Furthermore, the monomer composition of scl-co-mcl PHA was regulated by adjusting the amount of glucose and dodecanoic acid supplemented. Notably, the cell dry weight and scl-co-mcl PHA content reached 14.2 g/L and 60.1 wt %, respectively, when the engineered strain HT11Δ::phaCB was cultured in King's B medium containing 5 g/L glucose and 5 g/L dodecanoic acid. These results demonstrated that P. chlororaphis can be a platform for producing scl-co-mcl PHA and has the potential for industrial application.
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Affiliation(s)
- Ru-Xiang Deng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hui-Ling Li
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Wei Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hong-Bo Hu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- National Experimental Teaching Center for Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xue-Hong Zhang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
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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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Li J, Zhang X, Udduttula A, Fan ZS, Chen JH, Sun AR, Zhang P. Microbial-Derived Polyhydroxyalkanoate-Based Scaffolds for Bone Tissue Engineering: Biosynthesis, Properties, and Perspectives. Front Bioeng Biotechnol 2022; 9:763031. [PMID: 34993185 PMCID: PMC8724543 DOI: 10.3389/fbioe.2021.763031] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/17/2021] [Indexed: 01/15/2023] Open
Abstract
Polyhydroxyalkanoates (PHAs) are a class of structurally diverse natural biopolyesters, synthesized by various microbes under unbalanced culture conditions. PHAs as biomedical materials have been fabricated in various forms to apply to tissue engineering for the past years due to their excellent biodegradability, inherent biocompatibility, modifiable mechanical properties, and thermo-processability. However, there remain some bottlenecks in terms of PHA production on a large scale, the purification process, mechanical properties, and biodegradability of PHA, which need to be further resolved. Therefore, scientists are making great efforts via synthetic biology and metabolic engineering tools to improve the properties and the product yields of PHA at a lower cost for the development of various PHA-based scaffold fabrication technologies to widen biomedical applications, especially in bone tissue engineering. This review aims to outline the biosynthesis, structures, properties, and the bone tissue engineering applications of PHA scaffolds with different manufacturing technologies. The latest advances will provide an insight into future outlooks in PHA-based scaffolds for bone tissue engineering.
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Affiliation(s)
- Jian Li
- Shenzhen Engineering Research Center for Medical Bioactive Materials, Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xu Zhang
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Tsinghua University, Beijing, China.,Department of Chemical Engineering, Tsinghua University, Beijing, China
| | - Anjaneyulu Udduttula
- Shenzhen Engineering Research Center for Medical Bioactive Materials, Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Zhi Shan Fan
- Shenzhen Engineering Research Center for Medical Bioactive Materials, Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Jian Hai Chen
- Shenzhen Engineering Research Center for Medical Bioactive Materials, Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Antonia RuJia Sun
- Shenzhen Engineering Research Center for Medical Bioactive Materials, Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Peng Zhang
- Shenzhen Engineering Research Center for Medical Bioactive Materials, Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
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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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Soberón‐Chávez G, González‐Valdez A, Soto‐Aceves MP, Cocotl‐Yañez M. Rhamnolipids produced by Pseudomonas: from molecular genetics to the market. Microb Biotechnol 2021; 14:136-146. [PMID: 33151628 PMCID: PMC7888470 DOI: 10.1111/1751-7915.13700] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/18/2020] [Accepted: 10/20/2020] [Indexed: 12/31/2022] Open
Abstract
Rhamnolipids are biosurfactants with a wide range of industrial applications that entered into the market a decade ago. They are naturally produced by Pseudomonas aeruginosa and some Burkholderia species. Occasionally, some strains of different bacterial species, like Pseudomonas chlororaphis NRRL B-30761, which have acquired RL-producing ability by horizontal gene transfer, have been described. P. aeruginosa, the ubiquitous opportunistic pathogenic bacterium, is the best rhamnolipids producer, but Pseudomonas putida has been used as heterologous host for the production of this biosurfactant with relatively good yields. The molecular genetics of rhamnolipids production by P. aeruginosa has been widely studied not only due to the interest in developing overproducing strains, but because it is coordinately regulated with the expression of different virulence-related traits by the quorum-sensing response. Here, we highlight how the research of the molecular mechanisms involved in rhamnolipid production have impacted the development of strains that are suitable for industrial production of this biosurfactant, as well as some perspectives to improve these industrial useful strains.
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Affiliation(s)
- Gloria Soberón‐Chávez
- Departamento de Biología Molecular y BiotecnologíaInstituto de Investigaciones BiomédicasUniversidad Nacional Autónoma de MéxicoCiudad Universitaria, CDMXCoyoacanMéxico
| | - Abigail González‐Valdez
- Departamento de Biología Molecular y BiotecnologíaInstituto de Investigaciones BiomédicasUniversidad Nacional Autónoma de MéxicoCiudad Universitaria, CDMXCoyoacanMéxico
| | - Martín P. Soto‐Aceves
- Departamento de Biología Molecular y BiotecnologíaInstituto de Investigaciones BiomédicasUniversidad Nacional Autónoma de MéxicoCiudad Universitaria, CDMXCoyoacanMéxico
| | - Miguel Cocotl‐Yañez
- Departamento de Microbiología y ParasitologíaFacultad de MedicinaUniversidad Nacional Autónoma de MéxicoCiudad Universitaria, CDMXCoyoacanMéxico
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7
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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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Sohn YJ, Kim HT, Baritugo K, Jo SY, Song HM, Park SY, Park SK, Pyo J, Cha HG, Kim H, Na J, Park C, Choi J, Joo JC, Park SJ. Recent Advances in Sustainable Plastic Upcycling and Biopolymers. Biotechnol J 2020; 15:e1900489. [DOI: 10.1002/biot.201900489] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 02/05/2020] [Indexed: 12/27/2022]
Affiliation(s)
- Yu Jung Sohn
- Division of Chemical Engineering and Materials ScienceEwha Womans University 52 Ewhayeodae‐gil Seodaemun‐gu Seoul 03760 Republic of Korea
| | - Hee Taek Kim
- Biobased Chemistry Research Center, Advanced Convergent Chemistry DivisionKorea Research Institute of Chemical Technology P.O.Box 107, 141 Gajeong‐ro, Yuseong‐gu Daejeon 34114 Republic of Korea
| | - Kei‐Anne Baritugo
- Division of Chemical Engineering and Materials ScienceEwha Womans University 52 Ewhayeodae‐gil Seodaemun‐gu Seoul 03760 Republic of Korea
| | - Seo Young Jo
- Division of Chemical Engineering and Materials ScienceEwha Womans University 52 Ewhayeodae‐gil Seodaemun‐gu Seoul 03760 Republic of Korea
| | - Hye Min Song
- Division of Chemical Engineering and Materials ScienceEwha Womans University 52 Ewhayeodae‐gil Seodaemun‐gu Seoul 03760 Republic of Korea
| | - Se Young Park
- Division of Chemical Engineering and Materials ScienceEwha Womans University 52 Ewhayeodae‐gil Seodaemun‐gu Seoul 03760 Republic of Korea
| | - Su Kyeong Park
- Division of Chemical Engineering and Materials ScienceEwha Womans University 52 Ewhayeodae‐gil Seodaemun‐gu Seoul 03760 Republic of Korea
| | - Jiwon Pyo
- Division of Chemical Engineering and Materials ScienceEwha Womans University 52 Ewhayeodae‐gil Seodaemun‐gu Seoul 03760 Republic of Korea
| | - Hyun Gil Cha
- Bio‐based Chemistry Research Center, Advanced Convergent Chemistry DivisionKorea Research Institute of Chemical Technology (KRICT) Ulsan 44429 Republic of Korea
| | - Hoyong Kim
- Bio‐based Chemistry Research Center, Advanced Convergent Chemistry DivisionKorea Research Institute of Chemical Technology (KRICT) Ulsan 44429 Republic of Korea
| | - Jeong‐Geol Na
- Department of Chemical and Biomolecular EngineeringSogang University 35 Baekbumro Mapo‐gu Seoul 04107 Republic of Korea
| | - Chulhwan Park
- Department of Chemical EngineeringKwangwoon University 98‐2, Seokgye‐ro Nowon‐gu Seoul Republic of Korea
| | - Jong‐Il Choi
- Department of Biotechnology and Engineering, Interdisciplinary Program of Bioenergy and BiomaterialsChonnam National University Gwangju 61186 Republic of Korea
| | - Jeong Chan Joo
- Biobased Chemistry Research Center, Advanced Convergent Chemistry DivisionKorea Research Institute of Chemical Technology P.O.Box 107, 141 Gajeong‐ro, Yuseong‐gu Daejeon 34114 Republic of Korea
| | - Si Jae Park
- Division of Chemical Engineering and Materials ScienceEwha Womans University 52 Ewhayeodae‐gil Seodaemun‐gu Seoul 03760 Republic of Korea
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Metabolic engineering for the synthesis of polyesters: A 100-year journey from polyhydroxyalkanoates to non-natural microbial polyesters. Metab Eng 2020; 58:47-81. [DOI: 10.1016/j.ymben.2019.05.009] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/04/2019] [Accepted: 05/26/2019] [Indexed: 11/16/2022]
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Reddy MV, Mawatari Y, Onodera R, Nakamura Y, Yajima Y, Chang YC. Bacterial conversion of waste into polyhydroxybutyrate (PHB): A new approach of bio-circular economy for treating waste and energy generation. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.biteb.2019.100246] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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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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12
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Liu C, Qi L, Yang S, He Y, Jia X. Increased sedimentation of a Pseudomonas–Saccharomyces microbial consortium producing medium chain length polyhydroxyalkanoates. Chin J Chem Eng 2019. [DOI: 10.1016/j.cjche.2018.11.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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13
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Metabolic engineering of Escherichia coli for the synthesis of the quadripolymer poly(glycolate-co-lactate-co-3-hydroxybutyrate-co-4-hydroxybutyrate) from glucose. Metab Eng 2017; 44:38-44. [PMID: 28916461 DOI: 10.1016/j.ymben.2017.09.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 08/17/2017] [Accepted: 09/08/2017] [Indexed: 11/22/2022]
Abstract
Escherichia coli was metabolically engineered to effectively produce a series of biopolymers consisted of four types of monomers including glycolate, lactate, 3-hydroxybutyrate and 4-hydroxybutyrate from glucose as the carbon source. The biosynthetic route of novel quadripolymers was achieved by the overexpression of a range of homologous and heterologous enzymes including isocitrate lyase, isocitrate dehydrogenase kinase/phosphatase, glyoxylate/hydroxypyruvate reductase, propionyl-CoA transferase, β-ketothiolase, acetoacetyl-CoA reductase, succinate semialdehyde dehydrogenase, 4-hydroxybutyrate dehydrogenase, CoA transferase and PHA synthase. In shake flask cultures using Luria-Bertani medium supplemented with glucose, the recombinant E. coli reached 7.10g/l cell dry weight with 52.60wt% biopolymer content. In bioreactor study, the final cell dry weight was 19.61g/l, containing 14.29g/l biopolymer. The structure of the produced polymer was chemically characterized by proton NMR analysis. Assessment of thermal and mechanical properties demonstrated that the quadripolymer possessed decreased crystallinity and improved toughness, in comparison to poly-3-hydroxybutyrate homopolymer. This is the first study reporting efficient microbial production of the quadripolymer poly(glycolate-co-lactate-co-3-hydroxybutyrate-co-4-hydroxybutyrate) from glucose.
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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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