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Imai Y, Tominaga Y, Tanaka S, Yoshida M, Furutate S, Sato S, Koh S, Taguchi S. Modification of poly(lactate) via polymer blending with microbially produced poly[(R)-lactate-co-(R)-3-hydroxybutyrate] copolymers. Int J Biol Macromol 2024; 266:130990. [PMID: 38508553 DOI: 10.1016/j.ijbiomac.2024.130990] [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: 12/28/2023] [Revised: 03/11/2024] [Accepted: 03/16/2024] [Indexed: 03/22/2024]
Abstract
This study investigated the effect of polymer blending of microbially produced poly[(R)-lactate-co-(R)-3-hydroxybutyrate] copolymers (LAHB) with poly(lactate) (PLA) on their mechanical, thermal, and biodegradable properties. Blending of high lactate (LA) content and high molecular weight LAHB significantly improved the tensile elongation of PLA up to more than 250 % at optimal LAHB composition of 20-30 wt%. Temperature-modulated differential scanning calorimetry and dynamic mechanical analysis revealed that PLA and LAHB were immiscible but interacted with each other, as indicated by the mutual plasticization effect. Detailed morphological characterization using scanning probe microscopy, small-angle X-ray scattering, and solid-state NMR confirmed that PLA and LAHB formed a two-phase structure with a characteristic length scale as small as 20 nm. Because of mixing in this order, the polymer blends were optically transparent. The biological oxygen demand test of the polymer blends in seawater indicated an enhancement of PLA biodegradation during biodegradation of the polymer blends.
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Affiliation(s)
- Yusuke Imai
- Multi-Material Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 4-205, Sakurazaka, Moriyama-ku, Nagoya, Aichi 463-8560, Japan.
| | - Yuichi Tominaga
- Multi-Material Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 4-205, Sakurazaka, Moriyama-ku, Nagoya, Aichi 463-8560, Japan
| | - Shinji Tanaka
- Interdisciplinary Research Center for Catalytic Chemistry, AIST, Tsukuba, Ibaraki, Japan
| | - Masaru Yoshida
- Interdisciplinary Research Center for Catalytic Chemistry, AIST, Tsukuba, Ibaraki, Japan
| | | | | | - Sangho Koh
- Graduate School of Science, Technology and Innovation, Kobe University, Nada, Kobe 657-8501, Japan
| | - Seiichi Taguchi
- Graduate School of Science, Technology and Innovation, Kobe University, Nada, Kobe 657-8501, Japan; Engineering Biology Research Center, Kobe University, Nada, Kobe 657-8501, Japan.
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Mitsumori C, Tsuboi S, Shimamura M, Miura T. Application of MicroResp™ for quick and easy detection of plastic degradation by marine bacterial isolates. MARINE ENVIRONMENTAL RESEARCH 2024; 196:106430. [PMID: 38447329 DOI: 10.1016/j.marenvres.2024.106430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/26/2024] [Accepted: 02/26/2024] [Indexed: 03/08/2024]
Abstract
Microplastic debris in the marine environment is a global problem. Biodegradable polymers are being developed as alternatives to petroleum-based plastics, and quick and easy methods for screening for bacterial strains that can degrade such polymers are needed. As a screening method, the clear zone method has been widely used but has technical difficulties such as plate preparation and interpretation of results. In this study, we adapted the MicroResp™ system to easily detect biodegradation activity of marine bacteria in a 3-day assay. Among the 6 bacterial strains tested, 3, 2 and 1 strain degraded poly (butylene succinate-co-adipate) (PBSA), poly (ε-caprolactone) (PCL) and poly (3-hydroxybutyrate-co-3-hydroxyhexanoate), respectively. Only one strain that showed degradation activity of PBSA and PCL in the MicroResp™ system was also positive in the clear zone assay on the respective emulsion plates. Our results show that the adapted MicroResp™ system can screen for bacterial strains that degrade plastic.
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Affiliation(s)
- Cristina Mitsumori
- Biological Resource Center, National Institute of Technology and Evaluation (NBRC), Kisarazu, 292-0818, Japan
| | - Shun Tsuboi
- Biological Resource Center, National Institute of Technology and Evaluation (NBRC), Kisarazu, 292-0818, Japan.
| | - Mamiko Shimamura
- Biological Resource Center, National Institute of Technology and Evaluation (NBRC), Kisarazu, 292-0818, Japan
| | - Takamasa Miura
- Biological Resource Center, National Institute of Technology and Evaluation (NBRC), Kisarazu, 292-0818, Japan
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Matsumoto K. Toward the production of block copolymers in microbial cells: achievements and perspectives. Appl Microbiol Biotechnol 2024; 108:164. [PMID: 38252290 PMCID: PMC10803391 DOI: 10.1007/s00253-023-12973-8] [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: 10/02/2023] [Revised: 11/27/2023] [Accepted: 12/01/2023] [Indexed: 01/23/2024]
Abstract
The microbial production of polyhydroxyalkanoate (PHA) block copolymers has attracted research interests because they can be expected to exhibit excellent physical properties. Although post-polymerization conjugation and/or extension have been used for PHA block copolymer synthesis, the discovery of the first sequence-regulating PHA synthase, PhaCAR, enabled the direct synthesis of PHA-PHA type block copolymers in microbial cells. PhaCAR spontaneously synthesizes block copolymers from a mixture of substrates. To date, Escherichia coli and Ralstonia eutropha have been used as host strains, and therefore, sequence regulation is not a host-specific phenomenon. The monomer sequence greatly influences the physical properties of the polymer. For example, a random copolymer of 3-hydroxybutyrate and 2-hydroxybutyrate deforms plastically, while a block copolymer of approximately the same composition exhibits elastic deformation. The structure of the PHA block copolymer can be expanded by in vitro evolution of the sequence-regulating PHA synthase. An engineered variant of PhaCAR can synthesize poly(D-lactate) as a block copolymer component, which allows for greater flexibility in the molecular design of block copolymers. Therefore, creating sequence-regulating PHA synthases with a further broadened substrate range will expand the variety of properties of PHA materials. This review summarizes and discusses the sequence-regulating PHA synthase, analytical methods for verifying block sequence, properties of block copolymers, and mechanisms of sequence regulation. KEY POINTS: • Spontaneous monomer sequence regulation generates block copolymers • Poly(D-lactate) segment can be synthesized using a block copolymerization system • Block copolymers exhibit characteristic properties.
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Affiliation(s)
- Ken'ichiro Matsumoto
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Kitaku, Sapporo, N13W8060-8628, Japan.
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Kadoya R, Soga H, Matsuda M, Sato M, Taguchi S. Bacterial Population Changes during the Degradation Process of a Lactate (LA)-Enriched Biodegradable Polymer in River Water: LA-Cluster Preferable Bacterial Consortium. Polymers (Basel) 2023; 15:4111. [PMID: 37896354 PMCID: PMC10610160 DOI: 10.3390/polym15204111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/06/2023] [Accepted: 10/15/2023] [Indexed: 10/29/2023] Open
Abstract
The lactate-based polyester poly[lactate (LA)-co-3-hydroxybutyrate (3HB)], termed LAHB, is a highly transparent and flexible bio-based polymeric material. There are many unknowns regarding its degradation process in riverine environments, especially the changes in bacterial flora that might result from its degradation and the identities of any LAHB-degrading bacteria. LAHB were immersed in the river water samples (A and B), and LAHB degradation was observed in terms of the weight change of the polymer and the microscopic changes on the polymer surfaces. A metagenomic analysis of microorganisms was conducted to determine the effect of LAHB degradation on the aquatic environment. The bacterial flora obtained from beta diversity analysis differed between the two river samples. The river A water sample showed the simultaneous degradation of LA and 3HB even though the copolymer was LA-enriched, suggesting preferable hydrolysis of the LA-enriched segments. In contrast, only 3HB degraded for the LAHB in the river B water sample. The linear discriminant analysis effect size (LEfSe) analysis revealed 14 bacteria that were significantly increased in the river A water sample during LAHB degradation, suggesting that these bacteria preferentially degraded and assimilated LA-clustering polymers. Our metagenomic analysis provides useful insights into the dynamic changes in microbial communities and LA-clustering polymer-degrading bacteria.
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Affiliation(s)
- Ryosuke Kadoya
- Department of Food and Nutrition, School of Life Studies, Sugiyama Jogakuen University, 17-3 Hoshigaoka Motomachi, Chikusa-ku, Nagoya 464-8662, Aichi, Japan; (H.S.); (M.M.)
| | - Hitomi Soga
- Department of Food and Nutrition, School of Life Studies, Sugiyama Jogakuen University, 17-3 Hoshigaoka Motomachi, Chikusa-ku, Nagoya 464-8662, Aichi, Japan; (H.S.); (M.M.)
| | - Miki Matsuda
- Department of Food and Nutrition, School of Life Studies, Sugiyama Jogakuen University, 17-3 Hoshigaoka Motomachi, Chikusa-ku, Nagoya 464-8662, Aichi, Japan; (H.S.); (M.M.)
| | - Michio Sato
- Microbial Genetics Laboratory, Department of Agricultural Chemistry, Graduate School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawsaki 214-8571, Kanagawa, Japan;
| | - Seiichi Taguchi
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501, Hyogo, Japan;
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Nagao Y, Koh S, Taguchi S, Shimada T. Cell-growth phase-dependent promoter replacement approach for improved poly(lactate-co-3-hydroxybutyrate) production in Escherichia coli. Microb Cell Fact 2023; 22:131. [PMID: 37468909 DOI: 10.1186/s12934-023-02143-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 07/08/2023] [Indexed: 07/21/2023] Open
Abstract
Escherichia coli is a useful platform for producing valuable materials through the implementation of synthetic gene(s) derived from other organisms. The production of lactate (LA)-based polyester poly[LA-co-3-hydroxybutyrate (3HB)] was carried out in E. coli using a set of five other species-derived genes: Pseudomonas sp. 61-3-derived phaC1STQK (for polymerization), Cupriavidus necator-derived phaAB (for 3HB-CoA generation), and Megasphaera elsdenii-derived pct (for LA-CoA generation) cloned into pTV118NpctphaC1ps(ST/QK)AB. Here, we aimed to optimize the expression level and timing of these genes to improve the production of P(LA-co-3HB) and to manipulate the LA fraction by replacing the promoters with various promoters in E. coli. Evaluation of the effects of 21 promoter replacement plasmids revealed that the phaC1STQK-AB operon is critical for the stationary phase for P(LA-co-3HB) production. Interestingly, the effects of the promoters depended on the composition of the medium. In glucose-supplemented LB medium, the dps promoter replacement plasmid resulted in the greatest effect, increasing the accumulation to 8.8 g/L and an LA fraction of 14.1 mol% of P(LA-co-3HB), compared to 2.7 g/L and 8.1 mol% with the original plasmid. In xylose-supplemented LB medium, the yliH promoter replacement plasmid resulted in the greatest effect, with production of 5.6 g/L and an LA fraction of 40.2 mol% compared to 3.6 g/L and 22.6 mol% with the original plasmid. These results suggest that the selection of an appropriate promoter for expression of the phaC1STQK-AB operon could improve the production and LA fraction of P(LA-co-3HB). Here, we propose that the selection of cell-growth phase-dependent promoters is a versatile biotechnological strategy for effective intracellular production of polymeric materials such as P(LA-co-3HB), in combination with the selection of sugar-based carbon sources.
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Affiliation(s)
- Yuki Nagao
- School of Agriculture, Meiji University, 1-1-1 Kawasaki-Shi, Kanagawa, 214-8571, Japan
| | - Sangho Koh
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-Cho, Nada, Kobe, 657-8501, Japan
| | - Seiichi Taguchi
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-Cho, Nada, Kobe, 657-8501, Japan
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai-Cho, Nada, Kobe, 657-8501, Japan
| | - Tomohiro Shimada
- School of Agriculture, Meiji University, 1-1-1 Kawasaki-Shi, Kanagawa, 214-8571, Japan.
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Reprogramming microbial populations using a programmed lysis system to improve chemical production. Nat Commun 2021; 12:6886. [PMID: 34824227 PMCID: PMC8617184 DOI: 10.1038/s41467-021-27226-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 11/10/2021] [Indexed: 11/08/2022] Open
Abstract
Microbial populations are a promising model for achieving microbial cooperation to produce valuable chemicals. However, regulating the phenotypic structure of microbial populations remains challenging. In this study, a programmed lysis system (PLS) is developed to reprogram microbial cooperation to enhance chemical production. First, a colicin M -based lysis unit is constructed to lyse Escherichia coli. Then, a programmed switch, based on proteases, is designed to regulate the effective lysis unit time. Next, a PLS is constructed for chemical production by combining the lysis unit with a programmed switch. As a result, poly (lactate-co-3-hydroxybutyrate) production is switched from PLH synthesis to PLH release, and the content of free PLH is increased by 283%. Furthermore, butyrate production with E. coli consortia is switched from E. coli BUT003 to E. coli BUT004, thereby increasing butyrate production to 41.61 g/L. These results indicate the applicability of engineered microbial populations for improving the metabolic division of labor to increase the efficiency of microbial cell factories.
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Nduko JM, Taguchi S. Microbial Production of Biodegradable Lactate-Based Polymers and Oligomeric Building Blocks From Renewable and Waste Resources. Front Bioeng Biotechnol 2021; 8:618077. [PMID: 33614605 PMCID: PMC7889595 DOI: 10.3389/fbioe.2020.618077] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/17/2020] [Indexed: 12/20/2022] Open
Abstract
Polyhydroxyalkanoates (PHAs) are naturally occurring biopolymers produced by microorganisms. PHAs have become attractive research biomaterials in the past few decades owing to their extensive potential industrial applications, especially as sustainable alternatives to the fossil fuel feedstock-derived products such as plastics. Among the biopolymers are the bioplastics and oligomers produced from the fermentation of renewable plant biomass. Bioplastics are intracellularly accumulated by microorganisms as carbon and energy reserves. The bioplastics, however, can also be produced through a biochemistry process that combines fermentative secretory production of monomers and/or oligomers and chemical synthesis to generate a repertoire of biopolymers. PHAs are particularly biodegradable and biocompatible, making them a part of today's commercial polymer industry. Their physicochemical properties that are similar to those of petrochemical-based plastics render them potential renewable plastic replacements. The design of efficient tractable processes using renewable biomass holds key to enhance their usage and adoption. In 2008, a lactate-polymerizing enzyme was developed to create new category of polyester, lactic acid (LA)-based polymer and related polymers. This review aims to introduce different strategies including metabolic and enzyme engineering to produce LA-based biopolymers and related oligomers that can act as precursors for catalytic synthesis of polylactic acid. As the cost of PHA production is prohibitive, the review emphasizes attempts to use the inexpensive plant biomass as substrates for LA-based polymer and oligomer production. Future prospects and challenges in LA-based polymer and oligomer production are also highlighted.
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Affiliation(s)
- John Masani Nduko
- Department of Dairy and Food Science and Technology, Faculty of Agriculture, Egerton University, Egerton, Kenya
| | - Seiichi Taguchi
- Department of Chemistry for Life Sciences and Agriculture, Faculty of Life Sciences and Agriculture, Tokyo University of Agriculture, Tokyo, Japan
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Arai S, Sakakibara S, Mareschal R, Ooi T, Zinn M, Matsumoto K. Biosynthesis of Random-Homo Block Copolymer Poly[Glycolate- ran-3-Hydroxybutyrate (3HB)]- b-Poly(3HB) Using Sequence-Regulating Chimeric Polyhydroxyalkanoate Synthase in Escherichia coli. Front Bioeng Biotechnol 2020; 8:612991. [PMID: 33364233 PMCID: PMC7752996 DOI: 10.3389/fbioe.2020.612991] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 11/16/2020] [Indexed: 11/13/2022] Open
Abstract
Glycolate (GL)-containing polyhydroxyalkanoate (PHA) was synthesized in Escherichia coli expressing the engineered chimeric PHA synthase PhaC AR and coenzyme A transferase. The cells produced poly[GL-co-3-hydroxybutyrate (3HB)] with the supplementation of GL and 3HB, thus demonstrating that PhaC AR is the first known class I PHA synthase that is capable of incorporating GL units. The triad sequence analysis using 1H nuclear magnetic resonance indicated that the obtained polymer was composed of two distinct regions, a P(GL-ran-3HB) random segment and P(3HB) homopolymer segment. The random segment was estimated to contain a 71 mol% GL molar ratio, which was much greater than the value (15 mol%) previously achieved by using PhaC1 P s STQK. Differential scanning calorimetry analysis of the polymer films supported the presence of random copolymer and homopolymer phases. The solvent fractionation of the polymer indicated the presence of a covalent linkage between these segments. Therefore, it was concluded that PhaC AR synthesized a novel random-homo block copolymer, P(GL-ran-3HB)-b-P(3HB).
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Affiliation(s)
- Shuzo Arai
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Japan
| | - Sayaka Sakakibara
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Japan
| | - Robin Mareschal
- Department of Engineering, Hokkaido University, Sapporo, Japan
- Institute of Life Technologies, University of Applied Sciences and Arts Western Switzerland (HES-SO Valais-Wallis), Sion, Switzerland
| | - Toshihiko Ooi
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo, 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, Sapporo, Japan
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