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Arhin SG, Cesaro A, Di Capua F, Esposito G. Recent progress and challenges in biotechnological valorization of lignocellulosic materials: Towards sustainable biofuels and platform chemicals synthesis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159333. [PMID: 36220479 DOI: 10.1016/j.scitotenv.2022.159333] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 10/04/2022] [Accepted: 10/05/2022] [Indexed: 06/16/2023]
Abstract
Lignocellulosic materials (LCM) have garnered attention as feedstocks for second-generation biofuels and platform chemicals. With an estimated annual production of nearly 200 billion tons, LCM represent an abundant source of clean, renewable, and sustainable carbon that can be funneled to numerous biofuels and platform chemicals by sustainable microbial bioprocessing. However, the low bioavailability of LCM due to the recalcitrant nature of plant cell components, the complexity and compositional heterogeneity of LCM monomers, and the limited metabolic flexibility of wild-type product-forming microorganisms to simultaneously utilize various LCM monomers are major roadblocks. Several innovative strategies have been proposed recently to counter these issues and expedite the widespread commercialization of biorefineries using LCM as feedstocks. Herein, we critically summarize the recent advances in the biological valorization of LCM to value-added products. The review focuses on the progress achieved in the development of strategies that boost efficiency indicators such as yield and selectivity, minimize carbon losses via integrated biorefinery concepts, facilitate carbon co-metabolism and carbon-flux redirection towards targeted products using recently engineered microorganisms, and address specific product-related challenges, to provide perspectives on future research needs and developments. The strategies and views presented here could guide future studies in developing feasible and economically sustainable LCM-based biorefineries as a crucial node in achieving carbon neutrality.
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Affiliation(s)
- Samuel Gyebi Arhin
- Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125 Naples, Italy.
| | - Alessandra Cesaro
- Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125 Naples, Italy
| | - Francesco Di Capua
- School of Engineering, University of Basilicata, via dell'Ateneo Lucano 10, 85100 Potenza, Italy
| | - Giovanni Esposito
- Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125 Naples, Italy
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Carruthers DN, Lee TS. Diversifying Isoprenoid Platforms via Atypical Carbon Substrates and Non-model Microorganisms. Front Microbiol 2021; 12:791089. [PMID: 34925299 PMCID: PMC8677530 DOI: 10.3389/fmicb.2021.791089] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 11/10/2021] [Indexed: 01/07/2023] Open
Abstract
Isoprenoid compounds are biologically ubiquitous, and their characteristic modularity has afforded products ranging from pharmaceuticals to biofuels. Isoprenoid production has been largely successful in Escherichia coli and Saccharomyces cerevisiae with metabolic engineering of the mevalonate (MVA) and methylerythritol phosphate (MEP) pathways coupled with the expression of heterologous terpene synthases. Yet conventional microbial chassis pose several major obstacles to successful commercialization including the affordability of sugar substrates at scale, precursor flux limitations, and intermediate feedback-inhibition. Now, recent studies have challenged typical isoprenoid paradigms by expanding the boundaries of terpene biosynthesis and using non-model organisms including those capable of metabolizing atypical C1 substrates. Conversely, investigations of non-model organisms have historically informed optimization in conventional microbes by tuning heterologous gene expression. Here, we review advances in isoprenoid biosynthesis with specific focus on the synergy between model and non-model organisms that may elevate the commercial viability of isoprenoid platforms by addressing the dichotomy between high titer production and inexpensive substrates.
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Affiliation(s)
- David N Carruthers
- Joint BioEnergy Institute, Emeryville, CA, United States.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Taek Soon Lee
- Joint BioEnergy Institute, Emeryville, CA, United States.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
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Runguphan W, Sae-Tang K, Tanapongpipat S. Recent advances in the microbial production of isopentanol (3-Methyl-1-butanol). World J Microbiol Biotechnol 2021; 37:107. [PMID: 34043086 DOI: 10.1007/s11274-021-03074-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 05/17/2021] [Indexed: 10/21/2022]
Abstract
As the effects of climate change become increasingly severe, metabolic engineers and synthetic biologists are looking towards greener sources for transportation fuels. The design and optimization of microorganisms to produce gasoline, diesel, and jet fuel compounds from renewable feedstocks can significantly reduce dependence on fossil fuels and thereby produce fewer emissions. Over the past two decades, a tremendous amount of research has contributed to the development of microbial strains to produce advanced fuel compounds, including branched-chain higher alcohols (BCHAs) such as isopentanol (3-methyl-1-butanol; 3M1B) and isobutanol (2-methyl-1-propanol). In this review, we provide an overview of recent advances in the development of microbial strains for the production of isopentanol in both conventional and non-conventional hosts. We also highlight metabolic engineering strategies that may be employed to enhance product titers, reduce end-product toxicity, and broaden the substrate range to non-sugar carbon sources. Finally, we offer glimpses into some promising future directions in the development of isopentanol producing microbial strains.
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Affiliation(s)
- Weerawat Runguphan
- National Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Paholyothin Road, Klong 1, Klong Luang, 12120, Pathumthani, Thailand.
| | - Kittapong Sae-Tang
- National Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Paholyothin Road, Klong 1, Klong Luang, 12120, Pathumthani, Thailand
| | - Sutipa Tanapongpipat
- National Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Paholyothin Road, Klong 1, Klong Luang, 12120, Pathumthani, Thailand
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Liang H, Ma X, Ning W, Liu Y, Sinskey AJ, Stephanopoulos G, Zhou K. Constructing an ethanol utilization pathway in Escherichia coli to produce acetyl-CoA derived compounds. Metab Eng 2020; 65:223-231. [PMID: 33248272 DOI: 10.1016/j.ymben.2020.11.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 10/30/2020] [Accepted: 11/15/2020] [Indexed: 01/05/2023]
Abstract
Engineering microbes to utilize non-conventional substrates could create short and efficient pathways to convert substrate into product. In this study, we designed and constructed a two-step heterologous ethanol utilization pathway (EUP) in Escherichia coli by using acetaldehyde dehydrogenase (encoded by ada) from Dickeya zeae and alcohol dehydrogenase (encoded by adh2) from Saccharomyces cerevisiae. This EUP can convert ethanol into acetyl-CoA without ATP consumption, and generate two molecules of NADH per molecule of ethanol. We optimized the expression of these two genes and found that ethanol consumption could be improved by expressing them in a specific order (ada-adh2) with a constitutive promoter (PgyrA). The engineered E. coli strain with EUP consumed approximately 8 g/L of ethanol in 96 h when it was used as sole carbon source. Subsequently, we combined EUP with the biosynthesis of polyhydroxybutyrate (PHB), a biodegradable polymer derived from acetyl-CoA. The engineered E. coli strain carrying EUP and PHB biosynthetic pathway produced 1.1 g/L of PHB from 10 g/L of ethanol and 1 g/L of aspartate family amino acids in 96 h. We also engineered a E. coli strain to produce 24 mg/L of prenol in an ethanol-containing medium, supporting the feasibility of converting ethanol into different classes of acetyl-CoA derived compounds.
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Affiliation(s)
- Hong Liang
- Disruptive & Sustainable Technologies for Agricultural Precision (DiSTAP), Singapore-MIT Alliance for Research and Technology, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore
| | - Xiaoqiang Ma
- Disruptive & Sustainable Technologies for Agricultural Precision (DiSTAP), Singapore-MIT Alliance for Research and Technology, Singapore
| | - Wenbo Ning
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore
| | - Yurou Liu
- Disruptive & Sustainable Technologies for Agricultural Precision (DiSTAP), Singapore-MIT Alliance for Research and Technology, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore
| | - Anthony J Sinskey
- Disruptive & Sustainable Technologies for Agricultural Precision (DiSTAP), Singapore-MIT Alliance for Research and Technology, Singapore; Department of Biology, Massachusetts Institute of Technology, United States
| | - Gregory Stephanopoulos
- Disruptive & Sustainable Technologies for Agricultural Precision (DiSTAP), Singapore-MIT Alliance for Research and Technology, Singapore; Department of Chemical Engineering, Massachusetts Institute of Technology, United States.
| | - Kang Zhou
- Disruptive & Sustainable Technologies for Agricultural Precision (DiSTAP), Singapore-MIT Alliance for Research and Technology, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore.
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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: 11] [Impact Index Per Article: 2.8] [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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Liu Y, Chen J, Crisante D, Jaramillo Lopez JM, Mahadevan R. Dynamic Cell Programming with Quorum Sensing-Controlled CRISPRi Circuit. ACS Synth Biol 2020; 9:1284-1291. [PMID: 32485106 DOI: 10.1021/acssynbio.0c00148] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Synthetic biology is enabling rapid advances in the areas of biomanufacturing and live therapeutics. Dynamic circuits that can be used to regulate cellular resources and microbial community behavior represent a defining focus of synthetic biology, and have attracted tremendous interest. However, the existing dynamic circuits are mostly gene editing-dependent or cell lysis-based, which limits their broad and convenient application, and in some cases, such lysis-based circuits can suffer from genetic instability due to evolution. There is limited research in quorum sensing-assisted CRISPRi, which can function in a gene editing-independent manner. Here, we constructed a series of quorum sensing controlled CRISPRi systems (Q-CRISPRi), which can dynamically program bacteria by using customized sgRNA without introducing cell lysis. We successfully applied Q-CRISPRi circuits to dynamically program gene expression, population density, phenotype, physical property, and community composition of microbial consortia. The strategies reported here represent methods for dynamic cell programming and could be effective in programming industrially and medically important microorganisms to offer better control of their metabolism and behavior.
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Affiliation(s)
- Yilan Liu
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Jinjin Chen
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - David Crisante
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Jhoselyn Marisol Jaramillo Lopez
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Radhakrishnan Mahadevan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
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