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Nguyen N, Forstater JH, McIntosh JA. Decarboxylation in Natural Products Biosynthesis. JACS AU 2024; 4:2715-2745. [PMID: 39211618 PMCID: PMC11350588 DOI: 10.1021/jacsau.4c00425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 07/01/2024] [Accepted: 07/05/2024] [Indexed: 09/04/2024]
Abstract
Decarboxylation reactions are frequently found in the biosynthesis of primary and secondary metabolites. Decarboxylase enzymes responsible for these transformations operate via diverse mechanisms and act on a large variety of substrates, making them appealing in terms of biotechnological applications. This Perspective focuses on the occurrence of decarboxylation reactions in natural product biosynthesis and provides a perspective on their applications in biocatalysis for fine chemicals and pharmaceuticals.
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2
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Wang T, Ye P, Xu X, Lu M, Zhang X, Li N. Metabolic engineering combined with site-directed saturated mutations of α-keto acid decarboxylase for efficient production of 6-aminocaproic acid and 1,6-hexamethylenediamine. Biotechnol Bioeng 2024. [PMID: 38956978 DOI: 10.1002/bit.28795] [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: 04/22/2024] [Revised: 06/21/2024] [Accepted: 06/24/2024] [Indexed: 07/04/2024]
Abstract
6-Aminocaproic acid (6ACA) and 1,6-hexamethylenediamine (HMDA) are key precursors for nylon synthesis, and both are produced using petroleum-based chemical processes. However, the utilization of bio-based raw materials for biological production of monomers is crucial for nylon industry. In this study, we demonstrated that metabolic engineering of Escherichia coli and selected mutations of α-keto acid decarboxylase successfully synthesized 6ACA and HMDA. An artificial iterative cycle from l-lysine to chain-extended α-ketoacids was introduced into Escherichia coli BL21 (DE3). Then, the extended α-ketoacids were decarboxylated and oxidized for 6ACA production. Overexpression of catalase (KatE) combined with the site-directed mutations of α-isopropylmalate synthase (LeuA) contributed synergistic enhancement effect on synthesis of 6ACA, resulting in a 1.3-fold increase in 6ACA titer. Selected mutations in α-keto acid decarboxylase (KivD) improved its specificity and 170.00 ± 5.57 mg/L of 6ACA with a yield of 0.13 mol/mol (6ACA/ l-lysine hydrochloride) was achieved by shake flask cultivation of the engineered strain with the KivD# (F381Y/V461I). Meanwhile, the engineered E. coli could accumulate 84.67 ± 4.04 mg/L of HMDA with a yield of 0.08 mol/mol (HMDA/ l-lysine hydrochloride) by replacing aldehyde dehydrogenase with bi-aminotransferases. This achievement marks a significant advancement in the biological synthesis of 6-carbon compounds, since the biosynthetic pathways of HMDA are rarely identified.
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Affiliation(s)
- Tiantian Wang
- Innovation Center for Textile Science and Technology, College of Biological Science and Medical Engineering, Donghua University, Shanghai, People's Republic of China
| | - Pan Ye
- Innovation Center for Textile Science and Technology, College of Biological Science and Medical Engineering, Donghua University, Shanghai, People's Republic of China
| | - Xue Xu
- Innovation Center for Textile Science and Technology, College of Biological Science and Medical Engineering, Donghua University, Shanghai, People's Republic of China
| | - Mengqing Lu
- Innovation Center for Textile Science and Technology, College of Biological Science and Medical Engineering, Donghua University, Shanghai, People's Republic of China
| | - Xinyu Zhang
- Innovation Center for Textile Science and Technology, College of Biological Science and Medical Engineering, Donghua University, Shanghai, People's Republic of China
| | - Naiqiang Li
- Innovation Center for Textile Science and Technology, College of Biological Science and Medical Engineering, Donghua University, Shanghai, People's Republic of China
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3
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Lv K, Cao X, Pedroso MM, Wu B, Li J, He B, Schenk G. Structure-guided engineering of branched-chain α-keto acid decarboxylase for improved 1,2,4-butanetriol production by in vitro synthetic enzymatic biosystem. Int J Biol Macromol 2024; 255:128303. [PMID: 37992939 DOI: 10.1016/j.ijbiomac.2023.128303] [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: 08/08/2023] [Revised: 11/07/2023] [Accepted: 11/19/2023] [Indexed: 11/24/2023]
Abstract
Efficient synthetic routes for biomanufacturing chemicals often require the overcoming of pathway bottlenecks by tailoring enzymes to improve the catalytic efficiency or even implement non-native activities. 1,2,4-butanetriol (BTO), a valuable commodity chemical, is currently biosynthesized from D-xylose via a four-enzyme reaction cascade, with the ThDP-dependent α-keto acid decarboxylase (KdcA) identified as the potential bottleneck. Here, to further enhance the catalytic activity of KdcA toward the non-native substrate α-keto-3-deoxy-xylonate (KDX), in silico screening and structure-guided evolution were performed. The best mutants, S286L/G402P and V461K, exhibited a 1.8- and 2.5-fold higher enzymatic activity in the conversion of KDX to 3,4-dihydroxybutanal when compared to KdcA, respectively. MD simulations revealed that the two sets of mutations reshaped the substrate binding pocket, thereby increasing the binding affinity for KDX and promoting interactions between KDX and cofactor ThDP. Then, when the V461K mutant instead of wild type KdcA was integrated into the enzyme cascade, a 1.9-fold increase in BTO titer was observed. After optimization of the reaction conditions, the enzyme cocktail contained V461K converted 60 g/L D-xylose to 22.1 g/L BTO with a yield of 52.1 %. This work illustrated that protein engineering is a powerful tool for modifying the output of metabolic pathway.
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Affiliation(s)
- Kemin Lv
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Xuefei Cao
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Marcelo Monteiro Pedroso
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Brisbane, Australia
| | - Bin Wu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China.
| | - Jiahuang Li
- School of Biopharmacy, China Pharmaceutical University, Nanjing, China.
| | - Bingfang He
- School of Pharmaceutical Sciences, Nanjing Tech University, Nanjing, China
| | - Gerhard Schenk
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Brisbane, Australia
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4
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Shen X, Xu H, Wang T, Zhang R, Sun X, Yuan Q, Wang J. Rational protein engineering of a ketoacids decarboxylase for efficient production of 1,2,4-butanetriol from arabinose. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:172. [PMID: 37957743 PMCID: PMC10644656 DOI: 10.1186/s13068-023-02414-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 10/20/2023] [Indexed: 11/15/2023]
Abstract
BACKGROUND Lignocellulose, the most abundant non-edible feedstock on Earth, holds substantial potential for eco-friendly chemicals, fuels, and pharmaceuticals production. Glucose, xylose, and arabinose are primary components in lignocellulose, and their efficient conversion into high-value products is vital for economic viability. While glucose and xylose have been explored for such purpose, arabinose has been relatively overlooked. RESULTS This study demonstrates a microbial platform for producing 1,2,4-butanetriol (BTO) from arabinose, a versatile compound with diverse applications in military, polymer, rubber and pharmaceutical industries. The screening of the key pathway enzyme, keto acids decarboxylase, facilitated the production of 276.7 mg/L of BTO from arabinose in Escherichia coli. Through protein engineering of the rate-limiting enzyme KivD, which involved reducing the size of the binding pocket to accommodate a smaller substrate, its activity improved threefold, resulting in an increase in the BTO titer to 475.1 mg/L. Additionally, modular optimization was employed to adjust the expression levels of pathway genes, further enhancing BTO production to 705.1 mg/L. CONCLUSION The present study showcases a promising microbial platform for sustainable BTO production from arabinose. These works widen the spectrum of potential lignocellulosic products and lays the foundation for comprehensive utilization of lignocellulosic components.
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Affiliation(s)
- Xiaolin Shen
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China
| | - Hongchao Xu
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China
| | - Tong Wang
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China
| | - Ruihua Zhang
- College of Engineering, The University of Georgia, Athens, GA, 30602, USA
| | - Xinxiao Sun
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China
| | - Qipeng Yuan
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China.
| | - Jia Wang
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China.
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5
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Huang T, Ma Y. Advances in biosynthesis of higher alcohols in Escherichia coli. World J Microbiol Biotechnol 2023; 39:125. [PMID: 36941474 DOI: 10.1007/s11274-023-03580-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/13/2023] [Indexed: 03/23/2023]
Abstract
In recent years, the development of green energy to replace fossil fuels has been the focus of research. Higher alcohols are important biofuels and chemicals. The production of higher alcohols in microbes has gained attention due to its environmentally friendly character. Higher alcohols have been synthesized in model microorganism Escherichia coli, and the production has reached the gram level through enhancement of metabolic flow, the balance of reducing power and the optimization of fermentation processes. Sustainable bio-higher alcohols production is expected to replace fossil fuels as a green and renewable energy source. Therefore, this review summarizes the latest developments in producing higher alcohols (C3-C6) by E. coli, elucidate the main bottlenecks limiting the biosynthesis of higher alcohols, and proposes potential engineering strategies of improving the production of biological higher alcohols. This review would provide a theoretical basis for further research on higher alcohols production by E. coli.
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Affiliation(s)
- Tong Huang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China
| | - Yuanyuan Ma
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China.
- School of Marin Science and Technology, Tianjin University, Tianjin, 300072, China.
- R&D Center for Petrochemical Technology, Tianjin University, Tianjin, 300072, China.
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6
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Volk MJ, Tran VG, Tan SI, Mishra S, Fatma Z, Boob A, Li H, Xue P, Martin TA, Zhao H. Metabolic Engineering: Methodologies and Applications. Chem Rev 2022; 123:5521-5570. [PMID: 36584306 DOI: 10.1021/acs.chemrev.2c00403] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Metabolic engineering aims to improve the production of economically valuable molecules through the genetic manipulation of microbial metabolism. While the discipline is a little over 30 years old, advancements in metabolic engineering have given way to industrial-level molecule production benefitting multiple industries such as chemical, agriculture, food, pharmaceutical, and energy industries. This review describes the design, build, test, and learn steps necessary for leading a successful metabolic engineering campaign. Moreover, we highlight major applications of metabolic engineering, including synthesizing chemicals and fuels, broadening substrate utilization, and improving host robustness with a focus on specific case studies. Finally, we conclude with a discussion on perspectives and future challenges related to metabolic engineering.
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Affiliation(s)
- Michael J Volk
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Vinh G Tran
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Shih-I Tan
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
| | - Shekhar Mishra
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Zia Fatma
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Aashutosh Boob
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Hongxiang Li
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Pu Xue
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Teresa A Martin
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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7
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Hans S, Kumar N, Gohil N, Khambhati K, Bhattacharjee G, Deb SS, Maurya R, Kumar V, Reshamwala SMS, Singh V. Rebooting life: engineering non-natural nucleic acids, proteins and metabolites in microorganisms. Microb Cell Fact 2022; 21:100. [PMID: 35643549 PMCID: PMC9148472 DOI: 10.1186/s12934-022-01828-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 05/15/2022] [Indexed: 12/01/2022] Open
Abstract
The surging demand of value-added products has steered the transition of laboratory microbes to microbial cell factories (MCFs) for facilitating production of large quantities of important native and non-native biomolecules. This shift has been possible through rewiring and optimizing different biosynthetic pathways in microbes by exercising frameworks of metabolic engineering and synthetic biology principles. Advances in genome and metabolic engineering have provided a fillip to create novel biomolecules and produce non-natural molecules with multitude of applications. To this end, numerous MCFs have been developed and employed for production of non-natural nucleic acids, proteins and different metabolites to meet various therapeutic, biotechnological and industrial applications. The present review describes recent advances in production of non-natural amino acids, nucleic acids, biofuel candidates and platform chemicals.
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8
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Wong HSJ, Bhubalan K, Amirul AAA. A Critical Review on the Economically Feasible and Sustainable Poly(3-Hydroxybutyrate- co-3-hydroxyvalerate) Production from Alkyl Alcohols. Polymers (Basel) 2022; 14:670. [PMID: 35215584 PMCID: PMC8876610 DOI: 10.3390/polym14040670] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/03/2022] [Accepted: 02/05/2022] [Indexed: 01/14/2023] Open
Abstract
Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)) is the most studied short-chain-length polyhydroxyalkanoates (PHA) with high application importance in various fields. The domination of high-cost propionate and valerate over other 3-hydroxyvalerate (3HV) precursors owing to their wide preference among PHA-producing bacteria has hindered the development of diverse production processes. As alkyl alcohols are mainly produced from inexpensive starting materials through oxo synthesis, they contribute a cost-effective advantage over propionate and valerate. Moreover, alkyl alcohols can be biosynthesized from natural substrates and organic wastes. Despite their great potential, their toxicity to most PHA-producing bacteria has been the major drawback for their wide implementation as 3HV precursors for decades. Although the standard PHA-producing bacteria Cupriavidus necator showed promising alcohol tolerance, the 3HV yield was discouraging. Continuous discovery of alkyl alcohols-utilizing PHA-producing bacteria has enabled broader choices in 3HV precursor selection for diverse P(3HB-co-3HV) production processes with higher economic feasibility. Besides continuous effort in searching for promising wild-type strains, genetic engineering to construct promising recombinant strains based on the understanding of the mechanisms involved in alkyl alcohols toxicity and tolerance is an alternative approach. However, more studies are required for techno-economic assessment to analyze the economic performance of alkyl alcohol-based production compared to that of organic acids.
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Affiliation(s)
- Hau Seung Jeremy Wong
- School of Biological Sciences, Universiti Sains Malaysia, Gelugor 11800, Penang, Malaysia;
- Centre for Chemical Biology, Universiti Sains Malaysia, Bayan Lepas 11900, Penang, Malaysia
| | - Kesaven Bhubalan
- Eco-Innovation Research Interest Group, Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, Kuala Nerus 21030, Terengganu, Malaysia;
- Institute of Marine Biotechnology, Universiti Malaysia Terengganu, Kuala Nerus 21030, Terengganu, Malaysia
| | - Al-Ashraf Abdullah Amirul
- School of Biological Sciences, Universiti Sains Malaysia, Gelugor 11800, Penang, Malaysia;
- Centre for Chemical Biology, Universiti Sains Malaysia, Bayan Lepas 11900, Penang, Malaysia
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9
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Zhao L, Chen Z, Lin S, Wu T, Yu S, Huo YX. In Vitro Biosynthesis of Isobutyraldehyde Through the Establishment of a One-Step Self-Assembly-Based Immobilization Strategy. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:14609-14619. [PMID: 34818887 DOI: 10.1021/acs.jafc.1c05387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The in vitro biosynthesis of high-value compounds has become popular and attractive. The convenient and simple strategy of enzyme immobilization has been significant for continuous and efficient in vitro biosynthesis. On the basis of that, this work established a one-step self-assembly-based immobilization strategy to efficiently biosynthesize isobutyraldehyde in vitro. Isobutyraldehyde is a crucial precursor for the synthesis of foods and spices. The established CipA scaffold-based strategy can express and immobilize enzymes at the same time, and purification requires only one centrifugation step. Structural simulations indicated that this scaffold-dependent self-assembly did not influence the structure or catalytic mechanisms of the isobutyraldehyde production-related enzymes leucine dehydrogenase (LeuDH) and ketoisovalerate decarboxylase (Kivd). Immobilized LeuDH and Kivd displayed a higher conversion capacity and thermal stability than the free enzymes. Batch conversion experiments demonstrated that the recovered immobilized LeuDH and Kivd have similar conversion capacities to the enzymes used in the first round of reaction. The continuous production of isobutyraldehyde was achieved by filling the immobilized enzymes into the column of a constructed device. This study not only expands the application range of self-assembly systems but also provides guidance for the in vitro production of value-added compounds.
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Affiliation(s)
- Luyao Zhao
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian District, 100081 Beijing, China
| | - Zhenya Chen
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian District, 100081 Beijing, China
| | - Sheng Lin
- Beijing Key Laboratory of Microanalytical Methods and Instrumentation, MOE Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Department of Chemistry, Tsinghua University, Haidian District, 100084 Beijing, China
| | - Tong Wu
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian District, 100081 Beijing, China
| | - Shengzhu Yu
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian District, 100081 Beijing, China
| | - Yi-Xin Huo
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian District, 100081 Beijing, China
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10
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Bahls MO, Platz L, Morgado G, Schmidt GW, Panke S. Directed evolution of biofuel-responsive biosensors for automated optimization of branched-chain alcohol biosynthesis. Metab Eng 2021; 69:98-111. [PMID: 34767976 DOI: 10.1016/j.ymben.2021.10.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 10/21/2021] [Accepted: 10/31/2021] [Indexed: 12/18/2022]
Abstract
The biosynthesis of short-chain alcohols is a carbon-neutral alternative to petroleum-derived production, but strain screening operations are encumbered by laborious analytics. Here, we built, characterized and applied whole cell biosensors by directed evolution of the transcription factor AlkS for screening microbial strain libraries producing industrially relevant alcohols. A selected AlkS variant was applied for in situ product detection in two screening applications concerning key steps in alcohol production. Further, the biosensor strains enabled the implementation of an automated, robotic platform-based workflow with data clustering, which readily allowed the identification of significantly improved strain variants for isopentanol production.
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Affiliation(s)
- Maximilian O Bahls
- Department of Biosystems Science and Engineering, ETH Zurich, Switzerland
| | - Lukas Platz
- Department of Biosystems Science and Engineering, ETH Zurich, Switzerland
| | - Gaspar Morgado
- Department of Biosystems Science and Engineering, ETH Zurich, Switzerland
| | - Gregor W Schmidt
- Department of Biosystems Science and Engineering, ETH Zurich, Switzerland
| | - Sven Panke
- Department of Biosystems Science and Engineering, ETH Zurich, Switzerland.
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11
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Biocatalytic Conversion of Short-Chain Fatty Acids to Corresponding Alcohols in Escherichia coli. Processes (Basel) 2021. [DOI: 10.3390/pr9060973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Advanced biofuels possess superior characteristics to serve for gasoline substitutes. In this study, a whole cell biocatalysis system was employed for production of short-chain alcohols from corresponding fatty acids. To do so, Escherichia coli strain was equipped with a biocatalytic pathway consisting of endogenous atoDA and Clostridium acetobutylicum adhE2. The strain was further reprogrammed to improve its biocatalytic activity by direction the glycolytic flux to acetyl-CoA and recycling acetate. The production of 1-propanol and n-pentanol were exemplified with the engineered strain. By substrate (glucose and propionate) feeding, the strain enabled production of 5.4 g/L 1-propanol with productivity reaching 0.15 g/L/h. In addition, the strain with a heavy inoculum was implemented for the n-pentanol production from n-pentanoic acid. The production titer and productivity finally attained 4.3 g/L and 0.86 g/L/h, respectively. Overall, the result indicates that this developed system is useful and effective for biocatalytic production of short-chain alcohols.
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12
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Cheng J, Tu W, Luo Z, Gou X, Li Q, Wang D, Zhou J. A High-Efficiency Artificial Synthetic Pathway for 5-Aminovalerate Production From Biobased L-Lysine in Escherichia coli. Front Bioeng Biotechnol 2021; 9:633028. [PMID: 33634090 PMCID: PMC7900509 DOI: 10.3389/fbioe.2021.633028] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/20/2021] [Indexed: 12/11/2022] Open
Abstract
Bioproduction of 5-aminovalerate (5AVA) from renewable feedstock can support a sustainable biorefinery process to produce bioplastics, such as nylon 5 and nylon 56. In order to achieve the biobased production of 5AVA, a 2-keto-6-aminocaproate-mediated synthetic pathway was established. Combination of L-Lysine α-oxidase from Scomber japonicus, α-ketoacid decarboxylase from Lactococcus lactis and aldehyde dehydrogenase from Escherichia coli could achieve the biosynthesis of 5AVA from biobased L-Lysine in E. coli. The H2O2 produced by L-Lysine α-oxidase was decomposed by the expression of catalase KatE. Finally, 52.24 g/L of 5AVA were obtained through fed-batch biotransformation. Moreover, homology modeling, molecular docking and molecular dynamic simulation analyses were used to identify mutation sites and propose a possible trait-improvement strategy: the expanded catalytic channel of mutant and more hydrogen bonds formed might be beneficial for the substrates stretch. In summary, we have developed a promising artificial pathway for efficient 5AVA synthesis.
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Affiliation(s)
- Jie Cheng
- Key Laboratory of Meat Processing of Sichuan Province, Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture and Rural Affairs, College of Food and Biological Engineering, Chengdu University, Chengdu, China
| | - Wenying Tu
- Key Laboratory of Meat Processing of Sichuan Province, Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture and Rural Affairs, College of Food and Biological Engineering, Chengdu University, Chengdu, China
| | - Zhou Luo
- Key Laboratory of Meat Processing of Sichuan Province, Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture and Rural Affairs, College of Food and Biological Engineering, Chengdu University, Chengdu, China
| | - Xinghua Gou
- Key Laboratory of Meat Processing of Sichuan Province, Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture and Rural Affairs, College of Food and Biological Engineering, Chengdu University, Chengdu, China
| | - Qiang Li
- Key Laboratory of Meat Processing of Sichuan Province, Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture and Rural Affairs, College of Food and Biological Engineering, Chengdu University, Chengdu, China
| | - Dan Wang
- Department of Chemical Engineering, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, China
| | - Jingwen Zhou
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, China
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13
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Liang L, Liu R, Freed EF, Eckert CA. Synthetic Biology and Metabolic Engineering Employing Escherichia coli for C2-C6 Bioalcohol Production. Front Bioeng Biotechnol 2020; 8:710. [PMID: 32719784 PMCID: PMC7347752 DOI: 10.3389/fbioe.2020.00710] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/08/2020] [Indexed: 12/18/2022] Open
Abstract
Biofuel production from renewable and sustainable resources is playing an increasingly important role within the fuel industry. Among biofuels, bioethanol has been most widely used as an additive for gasoline. Higher alcohols can be blended at a higher volume compared to ethanol and generate lower greenhouse gas (GHG) emissions without a need to change current fuel infrastructures. Thus, these fuels have the potential to replace fossil fuels in support of more environmentally friendly processes. This review summarizes the efforts to enhance bioalcohol production in engineered Escherichia coli over the last 5 years and analyzes the current challenges for increasing productivities for industrial applications.
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Affiliation(s)
- Liya Liang
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO, United States
| | - Rongming Liu
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO, United States
| | - Emily F. Freed
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO, United States
| | - Carrie A. Eckert
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO, United States
- National Renewable Energy Laboratory, Golden, CO, United States
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14
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Li X, Cong Y, Ma M, You ZN, Gao B, Zhang JZH, Zhang L. An Energy Optimization Strategy Based on the Perfect Conformation of Prolyl Endopeptidase for Improving Catalytic Efficiency. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:5129-5137. [PMID: 32297517 DOI: 10.1021/acs.jafc.0c00731] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Prolyl endopeptidases (PEPs) hydrolyze proteins to yield bioactive peptides and are effective in the treatment of celiac disease. However, the catalytic efficiency of PEPs still has the potential to be improved, which could further strengthen their industrial and therapeutic applications. Herein, a novel rational design strategy based on a "near-attack conformation" of the catalytic state of PEP was adopted. Constrained dynamic simulations were applied, followed by the virtual screening of potentially favorable mutants according to their binding free energy. We redesigned Sphaerobacter thermophiles PEP with high-temperature activity/stability, a wide range of pH stabilities, and high proline specificity. As a result, the kcat value of two PEP mutants (I462W and Q560Y) increased by 208.2 and 150.1%, respectively, and the kcat/KM increased by 32.7 and 6.3%, respectively. These data revealed that the PEP mutants had improved catalytic efficiency and that our strategy can be applied for enzyme engineering.
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Affiliation(s)
- Xiaolin Li
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, Shanghai Key Laboratory of Green Chemistry & Chemical Process, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Yalong Cong
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, Shanghai Key Laboratory of Green Chemistry & Chemical Process, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Mingzhe Ma
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, Shanghai Key Laboratory of Green Chemistry & Chemical Process, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Zhi-Neng You
- School of Biotechnology, East China University of Science and Technology, Shanghai 200237, China
| | - Bei Gao
- School of Biotechnology, East China University of Science and Technology, Shanghai 200237, China
| | - John Z H Zhang
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, Shanghai Key Laboratory of Green Chemistry & Chemical Process, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai 200062, China
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Lujia Zhang
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, Shanghai Key Laboratory of Green Chemistry & Chemical Process, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai 200062, China
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15
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Xu L, Han F, Dong Z, Wei Z. Engineering Improves Enzymatic Synthesis of L-Tryptophan by Tryptophan Synthase from Escherichia coli. Microorganisms 2020; 8:microorganisms8040519. [PMID: 32260519 PMCID: PMC7232222 DOI: 10.3390/microorganisms8040519] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/02/2020] [Accepted: 04/03/2020] [Indexed: 11/20/2022] Open
Abstract
To improve the thermostability of tryptophan synthase, the molecular modification of tryptophan synthase was carried out by rational molecular engineering. First, B-FITTER software was used to analyze the temperature factor (B-factor) of each amino acid residue in the crystal structure of tryptophan synthase. A key amino acid residue, G395, which adversely affected the thermal stability of the enzyme, was identified, and then, a mutant library was constructed by site-specific saturation mutation. A mutant (G395S) enzyme with significantly improved thermal stability was screened from the saturated mutant library. Error-prone PCR was used to conduct a directed evolution of the mutant enzyme (G395S). Compared with the parent, the mutant enzyme (G395S /A191T) had a Km of 0.21 mM and a catalytic efficiency kcat/Km of 5.38 mM−1∙s−1, which was 4.8 times higher than that of the wild-type strain. The conditions for L-tryptophan synthesis by the mutated enzyme were a L-serine concentration of 50 mmol/L, a reaction temperature of 40 °C, pH of 8, a reaction time of 12 h, and an L-tryptophan yield of 81%. The thermal stability of the enzyme can be improved by using an appropriate rational design strategy to modify the correct site. The catalytic activity of tryptophan synthase was increased by directed evolution.
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Affiliation(s)
- Lisheng Xu
- Department of Life and Food Science, Suzhou University, Suzhou 234000, China; (F.H.); (Z.D.)
- Correspondence: ; Tel.: +86-557-287-1681
| | - Fangkai Han
- Department of Life and Food Science, Suzhou University, Suzhou 234000, China; (F.H.); (Z.D.)
| | - Zeng Dong
- Department of Life and Food Science, Suzhou University, Suzhou 234000, China; (F.H.); (Z.D.)
| | - Zhaojun Wei
- School of Food and Biological Engineering, Hefei University of Technology, Hefei 230009, China;
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16
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Hammer SK, Zhang Y, Avalos JL. Mitochondrial Compartmentalization Confers Specificity to the 2-Ketoacid Recursive Pathway: Increasing Isopentanol Production in Saccharomyces cerevisiae. ACS Synth Biol 2020; 9:546-555. [PMID: 32049515 DOI: 10.1021/acssynbio.9b00420] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recursive elongation pathways produce compounds of increasing carbon-chain length with each iterative cycle. Of particular interest are 2-ketoacids derived from recursive elongation, which serve as precursors to a valuable class of advanced biofuels known as branched-chain higher alcohols (BCHAs). Protein engineering has been used to increase the number of iterative elongation cycles completed, yet specific production of longer-chain 2-ketoacids remains difficult to achieve. Here, we show that mitochondrial compartmentalization is an effective strategy to increase specificity of recursive pathways to favor longer-chain products. Using 2-ketoacid elongation as a proof of concept, we show that overexpression of the three elongation enzymes-LEU4, LEU1, and LEU2-in mitochondria of an isobutanol production strain results in a 2.3-fold increase in the isopentanol to isobutanol product ratio relative to overexpressing the same elongation enzymes in the cytosol, and a 31-fold increase relative to wild-type enzyme expression. Reducing the loss of intermediates allows us to further boost isopentanol production to 1.24 ± 0.06 g/L of isopentanol. In this strain, isopentanol accounts for 86% of the total BCHAs produced, while achieving the highest isopentanol titer reported for Saccharomyces cerevisiae. Localizing the elongation enzymes in mitochondria enables the development of strains in which isopentanol constitutes as much as 93% of BCHA production. This work establishes mitochondrial compartmentalization as a new approach to favor high titers and product specificities of larger products from recursive pathways.
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Affiliation(s)
- Sarah K. Hammer
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Yanfei Zhang
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - José L. Avalos
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, United States
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, United States
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17
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Production of nonnatural straight-chain amino acid 6-aminocaproate via an artificial iterative carbon-chain-extension cycle. Metab Eng 2019; 55:23-32. [DOI: 10.1016/j.ymben.2019.06.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 06/13/2019] [Accepted: 06/15/2019] [Indexed: 12/23/2022]
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18
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Morris DM, Quintana RL, Harvey BG. High-Performance Jet Fuels Derived from Bio-Based Alkenes by Iron-Catalyzed [2+2] Cycloaddition. CHEMSUSCHEM 2019; 12:1646-1652. [PMID: 30908903 DOI: 10.1002/cssc.201802588] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/18/2019] [Accepted: 01/23/2019] [Indexed: 06/09/2023]
Abstract
A series of high-performance cycloparaffinic fuels have been generated by [2+2] cycloaddition of the bio-derived alkenes 1-hexene, isoprene, and 1-pentene, catalyzed by a low-valent iron pyridine(diimine) complex [(Me PDI)Fe(N2 )2 (μ-N2 )] [Me PDI=N,N'-(2,6-pyridinediyldiethylidyne)bis(2,6-dimethylbenzenamine)]. Reactions with 1-pentene and 1-hexene resulted in 85 % selectivity to 1,2-cyclobutanes, and 12 % selectivity to acyclic alkenes generated by β-hydride elimination. Self-dimerization of isoprene was sluggish and generated heavier oligomer products, but cross-dimerization of isoprene with 1-hexene afforded primarily a 1,3-cyclobutane product, along with isomers of acyclic C11 mixed dimers. Hydrocarbon mixtures were hydrogenated and fractionally distilled to yield finished fuel mixtures in overall yields of 83-93 % at the multigram scale. The fuels exhibited densities ranging between 0.767 and 0.783 g mL-1 , and net heats of combustion (NHOC) of up to 120.6 kBtu gal-1 (43.8 MJ kg-1 ). These values are higher than conventional synthetic paraffinic kerosenes owing to the higher density and ring strain afforded by the cyclobutane rings. The fuel mixtures also exhibited extremely low viscosities ranging from 2.38 to 4.78 mm2 s-1 at -20 °C, due in part to the presence of the acyclic dimers. The excellent fuel properties of the product mixtures, selectivity for dimer products, high yields, and the ability to use simple bio-derived alkenes as substrates, make the [Fe]-catalyzed [2+2] cycloaddition of unactivated alkenes a compelling route to the synthesis of sustainable high-performance fuels.
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Affiliation(s)
- David M Morris
- Chemistry Division, US NAVY, NAWCWD, Research Department, China Lake, California, 93555, USA
| | - Roxanne L Quintana
- Chemistry Division, US NAVY, NAWCWD, Research Department, China Lake, California, 93555, USA
| | - Benjamin G Harvey
- Chemistry Division, US NAVY, NAWCWD, Research Department, China Lake, California, 93555, USA
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19
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Nitta K, Laviña WA, Pontrelli S, Liao JC, Putri SP, Fukusaki E. Metabolome analysis revealed the knockout of glyoxylate shunt as an effective strategy for improvement of 1-butanol production in transgenic Escherichia coli. J Biosci Bioeng 2019; 127:301-308. [DOI: 10.1016/j.jbiosc.2018.08.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 08/27/2018] [Accepted: 08/28/2018] [Indexed: 10/28/2022]
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20
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Miao R, Xie H, M Ho F, Lindblad P. Protein engineering of α-ketoisovalerate decarboxylase for improved isobutanol production in Synechocystis PCC 6803. Metab Eng 2018; 47:42-48. [PMID: 29501927 DOI: 10.1016/j.ymben.2018.02.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/12/2018] [Accepted: 02/25/2018] [Indexed: 12/13/2022]
Abstract
Protein engineering is a powerful tool to modify e.g. protein stability, activity and substrate selectivity. Heterologous expression of the enzyme α-ketoisovalerate decarboxylase (Kivd) in the unicellular cyanobacterium Synechocystis PCC 6803 results in cells producing isobutanol and 3-methyl-1-butanol, with Kivd identified as a potential bottleneck. In the present study, we used protein engineering of Kivd to improve isobutanol production in Synechocystis PCC 6803. Isobutanol is a flammable compound that can be used as a biofuel due to its high energy density and suitable physical and chemical properties. Single replacement, either Val461 to isoleucine or Ser286 to threonine, increased the Kivd activity significantly, both in vivo and in vitro resulting in increased overall production while isobutanol production was increased more than 3-methyl-1-butanol production. Moreover, among all the engineered strains examined, the strain with the combined modification V461I/S286T showed the highest (2.4 times) improvement of isobutanol-to-3M1B molar ratio, which was due to a decrease of the activity towards 3M1B production. Protein engineering of Kivd resulted in both enhanced total catalytic activity and preferential shift towards isobutanol production in Synechocystis PCC 6803.
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Affiliation(s)
- Rui Miao
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden.
| | - Hao Xie
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden.
| | - Felix M Ho
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden.
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden.
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21
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Mori Y, Shirai T. Designing artificial metabolic pathways, construction of target enzymes, and analysis of their function. Curr Opin Biotechnol 2018; 54:41-44. [PMID: 29452926 DOI: 10.1016/j.copbio.2018.01.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 12/26/2017] [Accepted: 01/22/2018] [Indexed: 11/24/2022]
Abstract
Artificial design of metabolic pathways is essential for the production of useful compounds using microbes. Based on this design, heterogeneous genes are introduced into the host, and then various analysis and evaluation methods are conducted to ensure that the target enzyme reactions are functionalized within the cell. In this chapter, we list successful examples of useful compounds produced by designing artificial metabolic pathways, and describe the methods involved in analyzing, evaluating, and optimizing the target enzyme reaction.
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Affiliation(s)
- Yutaro Mori
- Biomass Engineering Research Division, Center for Sustainable Resource Science, RIKEN, 1-7-22, Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Tomokazu Shirai
- Biomass Engineering Research Division, Center for Sustainable Resource Science, RIKEN, 1-7-22, Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.
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22
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Steps towards 'drop-in' biofuels: focusing on metabolic pathways. Curr Opin Biotechnol 2017; 53:26-32. [PMID: 29207330 DOI: 10.1016/j.copbio.2017.10.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 10/27/2017] [Accepted: 10/30/2017] [Indexed: 12/20/2022]
Abstract
The past decade has witnessed rapid advance in microbial production of 'drop-in' biofuels from renewable resources. Various biosynthetic pathways have been constructed to produce biofuels with diverse structures, and multiple metabolic engineering strategies have been developed to increase biofuel titers, yields, productivities and system robustness. In this review, we intend to give a brief but comprehensive overview of the most recent progresses on four essential pathways leading to 'drop-in' biofuel production, with an emphasis on the metabolic pathway efficiencies and biofuel structures. Furthermore, we also provide an insightful discussion on optimization strategies to improve the robustness of the microbial platforms for biofuel production.
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