1
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Muth-Pawlak D, Kakko L, Kallio P, Aro EM. Interplay between photosynthetic electron flux and organic carbon sinks in sucrose-excreting Synechocystis sp. PCC 6803 revealed by omics approaches. Microb Cell Fact 2024; 23:188. [PMID: 38951789 PMCID: PMC11218172 DOI: 10.1186/s12934-024-02462-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 06/17/2024] [Indexed: 07/03/2024] Open
Abstract
BACKGROUND Advancing the engineering of photosynthesis-based prokaryotic cell factories is important for sustainable chemical production and requires a deep understanding of the interplay between bioenergetic and metabolic pathways. Rearrangements in photosynthetic electron flow to increase the efficient use of the light energy for carbon fixation must be balanced with a strong carbon sink to avoid photoinhibition. In the cyanobacterium Synechocystis sp. PCC 6803, the flavodiiron protein Flv3 functions as an alternative electron acceptor of photosystem I and represents an interesting engineering target for reorganizing electron flow in attempts to enhance photosynthetic CO2 fixation and increase production yield. RESULTS We have shown that inactivation of Flv3 in engineered sucrose-excreting Synechocystis (S02:Δflv3) induces a transition from photoautotrophic sucrose production to mixotrophic growth sustained by sucrose re-uptake and the formation of intracellular carbon sinks such as glycogen and polyhydroxybutyrate. The growth of S02:Δflv3 exceeds that of the sucrose-producing strain (S02) and demonstrates unforeseen proteomic and metabolomic changes over the course of the nine-day cultivation. In the absence of Flv3, a down-regulation of proteins related to photosynthetic light reactions and CO2 assimilation occurred concomitantly with up-regulation of those related to glycolytic pathways, before any differences in sucrose production between S02 and S02:Δflv3 strains were observed. Over time, increased sucrose degradation in S02:Δflv3 led to the upregulation of respiratory pathway components, such as the plastoquinone reductase complexes NDH-11 and NDH-2 and the terminal respiratory oxidases Cyd and Cox, which transfer electrons to O2. While glycolytic metabolism is significantly up-regulated in S02:Δflv3 to provide energy for the cell, the accumulation of intracellular storage compounds and the increase in respiration serve as indirect sinks for photosynthetic electrons. CONCLUSIONS Our results show that the presence of strong carbon sink in the engineered sucrose-producing Synechocystis S02 strain, operating under high light, high CO2 and salt stress, cannot compensate for the lack of Flv3 by directly balancing the light transducing source and carbon fixing sink reactions. Instead, the cells immediately sense the imbalance, leading to extensive reprogramming of cellular bioenergetic, metabolic and ion transport pathways that favor mixotrophic growth rather than enhancing photoautotrophic sucrose production.
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Affiliation(s)
- Dorota Muth-Pawlak
- Department of Life Technologies, Molecular Plant Biology, University of Turku, Turku, FIN-20014, Finland.
| | - Lauri Kakko
- Department of Life Technologies, Molecular Plant Biology, University of Turku, Turku, FIN-20014, Finland
| | - Pauli Kallio
- Department of Life Technologies, Molecular Plant Biology, University of Turku, Turku, FIN-20014, Finland
| | - Eva-Mari Aro
- Department of Life Technologies, Molecular Plant Biology, University of Turku, Turku, FIN-20014, Finland
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2
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Wu M, Shi Z, Ming Y, Zhao Y, Gao G, Li G, Ma T. The production of ultrahigh molecular weight xanthan gum from a Sphingomonas chassis capable of co-utilising glucose and xylose from corn straw. Microb Biotechnol 2024; 17:e14394. [PMID: 38226955 PMCID: PMC10884872 DOI: 10.1111/1751-7915.14394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 11/23/2023] [Accepted: 12/19/2023] [Indexed: 01/17/2024] Open
Abstract
Corn straw is an abundant and renewable alternative for microbial biopolymer production. In this paper, an engineered Sphingomonas sanxanigenens NXG-P916 capable of co-utilising glucose and xylose from corn straw total hydrolysate to produce xanthan gum was constructed. This strain was obtained by introducing the xanthan gum synthetic operon gum as a module into the genome of the constructed chassis strain NXdPE that could mass produce activated precursors of polysaccharide, and in which the transcriptional levels of gum genes were optimised by screening for a more appropriate promoter, P916 . As a result, strain NXG-P916 produced 9.48 ± 0.34 g of xanthan gum per kg of fermentation broth (g/kg) when glucose was used as a carbon source, which was 2.1 times improved over the original engineering strain NXdPE::gum. Furthermore, in batch fermentation, 12.72 ± 0.75 g/kg xanthan gum was produced from the corn straw total hydrolysate containing both glucose and xylose, and the producing xanthan gum showed an ultrahigh molecular weight (UHMW) of 6.04 × 107 Da, which was increased by 15.8 times. Therefore, the great potential of producing UHMW xanthan gum by Sphingomonas sanxanigenens was proved, and the chassis NXdPE has the prospect of becoming an attractive platform organism producing polysaccharides derived from biomass hydrolysates.
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Affiliation(s)
- Mengmeng Wu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life SciencesNankai UniversityTianjinChina
| | - Zhuangzhuang Shi
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life SciencesNankai UniversityTianjinChina
| | - Yue Ming
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life SciencesNankai UniversityTianjinChina
| | - Yufei Zhao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life SciencesNankai UniversityTianjinChina
| | - Ge Gao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life SciencesNankai UniversityTianjinChina
| | - Guoqiang Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life SciencesNankai UniversityTianjinChina
| | - Ting Ma
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life SciencesNankai UniversityTianjinChina
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3
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Song X, Ju Y, Chen L, Zhang W. Construction of Xylose-Utilizing Cyanobacterial Chassis for Bioproduction Under Photomixotrophic Conditions. Methods Mol Biol 2024; 2760:57-75. [PMID: 38468082 DOI: 10.1007/978-1-0716-3658-9_4] [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] [Indexed: 03/13/2024]
Abstract
Xylose is a major component of lignocellulose and the second most abundant sugar present in nature after glucose; it, therefore, has been considered to be a promising renewable resource for the production of biofuels and chemicals. However, no natural cyanobacterial strain is known capable of utilizing xylose. Here, we take the fast-growing cyanobacteria Synechococcus elongatus UTEX 2973 as an example to develop the synthetic biology-based methodology of constructing a new xylose-utilizing cyanobacterial chassis with increased acetyl-CoA for bioproduction.
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Affiliation(s)
- Xinyu Song
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, People's Republic of China
- Key Laboratory of Systems Bioengineering and Frontier Science Center of Synthetic Biology, The Ministry of Education of China, Tianjin University, Tianjin, People's Republic of China
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin, People's Republic of China
| | - Yue Ju
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, People's Republic of China
- Key Laboratory of Systems Bioengineering and Frontier Science Center of Synthetic Biology, The Ministry of Education of China, Tianjin University, Tianjin, People's Republic of China
| | - Lei Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, People's Republic of China
- Key Laboratory of Systems Bioengineering and Frontier Science Center of Synthetic Biology, The Ministry of Education of China, Tianjin University, Tianjin, People's Republic of China
| | - Weiwen Zhang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, People's Republic of China.
- Key Laboratory of Systems Bioengineering and Frontier Science Center of Synthetic Biology, The Ministry of Education of China, Tianjin University, Tianjin, People's Republic of China.
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin, People's Republic of China.
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4
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Sun J, Zhang Z, Zhang S, Dan Y, Sun H, Wu Y, Luan G, Lu X. Engineering Cyanobacterial Cell Factories for Photosynthetic Production of Fructose. ACS Synth Biol 2023; 12:3008-3019. [PMID: 37728873 DOI: 10.1021/acssynbio.3c00338] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
Fructose is an important monosaccharide product widely applied in the food, medicine, and chemical industries. Currently, fructose is mainly manufactured with plant biomass-sourced polysaccharides through multiple steps of digestion, conversion, separation, and purification. The development of cyanobacterial metabolic engineering provides an attractive alternative route for the one-step direct production of fructose utilizing carbon dioxide and solar energy. In this work, we developed a paradigm for engineering cyanobacterial chassis cells into efficient cell factories for the photosynthetic production of fructose. In a representative cyanobacterial strain, Synechococcus elongatus PCC 7942, knockout of fructokinase effectively activated the synthesis and secretion of fructose in hypersaline conditions, independent of any heterologous transporters. The native sucrose synthesis pathway was identified as playing a primary role in fructose synthesis. Through combinatory optimizations on the levels of metabolism, physiology, and cultivation, the fructose yield of the Synechococcus cell factories was stepwise improved to 3.9 g/L. Such a paradigm was also adopted to engineer another Synechococcus strain, the marine species Synechococcus sp. PCC 7002, and facilitated an even higher fructose yield of over 6 g/L. Finally, the fructose synthesized and secreted by the cyanobacterial photosynthetic cell factories was successfully extracted and prepared from the culture broth in the form of products with 86% purity through multistep separation-purification operations. This work demonstrated a paradigm for systematically engineering cyanobacteria for photosynthetic production of desired metabolites, and it also confirmed the feasibility and potential of cyanobacterial photosynthetic biomanufacturing as a simple and efficient route for fructose production.
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Affiliation(s)
- Jiahui Sun
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, China
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
- College of Life Science, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Zhichao Zhang
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, China
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
| | - Shanshan Zhang
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, China
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
- College of Life Science, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Yu Dan
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, China
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
| | - Huili Sun
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, China
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
- College of Life Science, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Yannan Wu
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, China
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
| | - Guodong Luan
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, China
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
- College of Life Science, University of Chinese Academy of Sciences, 100049 Beijing, China
- Dalian National Laboratory for Clean Energy, Dalian, Liaoning 116023, China
| | - Xuefeng Lu
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, China
- Shandong Energy Institute, No. 189 Songling Road, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
- College of Life Science, University of Chinese Academy of Sciences, 100049 Beijing, China
- Dalian National Laboratory for Clean Energy, Dalian, Liaoning 116023, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China
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5
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Gonzales JN, Treece TR, Mayfield SP, Simkovsky R, Atsumi S. Utilization of lignocellulosic hydrolysates for photomixotrophic chemical production in Synechococcus elongatus PCC 7942. Commun Biol 2023; 6:1022. [PMID: 37813969 PMCID: PMC10562401 DOI: 10.1038/s42003-023-05394-w] [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: 07/06/2023] [Accepted: 09/27/2023] [Indexed: 10/11/2023] Open
Abstract
To meet the need for environmentally friendly commodity chemicals, feedstocks for biological chemical production must be diversified. Lignocellulosic biomass are an carbon source with the potential for effective use in a large scale and cost-effective production systems. Although the use of lignocellulosic biomass lysates for heterotrophic chemical production has been advancing, there are challenges to overcome. Here we aim to investigate the obligate photoautotroph cyanobacterium Synechococcus elongatus PCC 7942 as a chassis organism for lignocellulosic chemical production. When modified to import monosaccharides, this cyanobacterium is an excellent candidate for lysates-based chemical production as it grows well at high lysate concentrations and can fix CO2 to enhance carbon efficiency. This study is an important step forward in enabling the simultaneous use of two sugars as well as lignocellulosic lysate. Incremental genetic modifications enable catabolism of both sugars concurrently without experiencing carbon catabolite repression. Production of 2,3-butanediol is demonstrated to characterize chemical production from the sugars in lignocellulosic hydrolysates. The engineered strain achieves a titer of 13.5 g L-1 of 2,3-butanediol over 12 days under shake-flask conditions. This study can be used as a foundation for industrial scale production of commodity chemicals from a combination of sunlight, CO2, and lignocellulosic sugars.
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Affiliation(s)
- Jake N Gonzales
- Plant Biology Graduate Group, University of California, Davis, Davis, CA, 95616, USA
| | - Tanner R Treece
- Department of Chemistry, University of California, Davis, Davis, CA, 95616, USA
| | - Stephen P Mayfield
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
- California Center for Algae Biotechnology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Ryan Simkovsky
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
- California Center for Algae Biotechnology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Shota Atsumi
- Plant Biology Graduate Group, University of California, Davis, Davis, CA, 95616, USA.
- Department of Chemistry, University of California, Davis, Davis, CA, 95616, USA.
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6
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Kugler A, Stensjö K. Optimal energy and redox metabolism in the cyanobacterium Synechocystis sp. PCC 6803. NPJ Syst Biol Appl 2023; 9:47. [PMID: 37739963 PMCID: PMC10516873 DOI: 10.1038/s41540-023-00307-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Accepted: 09/01/2023] [Indexed: 09/24/2023] Open
Abstract
Understanding energy and redox homeostasis and carbon partitioning is crucial for systems metabolic engineering of cell factories. Carbon metabolism alone cannot achieve maximal accumulation of metabolites in production hosts, since an efficient production of target molecules requires energy and redox balance, in addition to carbon flow. The interplay between cofactor regeneration and heterologous production in photosynthetic microorganisms is not fully explored. To investigate the optimality of energy and redox metabolism, while overproducing alkenes-isobutene, isoprene, ethylene and 1-undecene, in the cyanobacterium Synechocystis sp. PCC 6803, we applied stoichiometric metabolic modelling. Our network-wide analysis indicates that the rate of NAD(P)H regeneration, rather than of ATP, controls ATP/NADPH ratio, and thereby bioproduction. The simulation also implies that energy and redox balance is interconnected with carbon and nitrogen metabolism. Furthermore, we show that an auxiliary pathway, composed of serine, one-carbon and glycine metabolism, supports cellular redox homeostasis and ATP cycling. The study revealed non-intuitive metabolic pathways required to enhance alkene production, which are mainly driven by a few key reactions carrying a high flux. We envision that the presented comparative in-silico metabolic analysis will guide the rational design of Synechocystis as a photobiological production platform of target chemicals.
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Affiliation(s)
- Amit Kugler
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE-751 20, Uppsala, Sweden
| | - Karin Stensjö
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE-751 20, Uppsala, Sweden.
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7
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Stebegg R, Schmetterer G, Rompel A. Heterotrophy among Cyanobacteria. ACS OMEGA 2023; 8:33098-33114. [PMID: 37744813 PMCID: PMC10515406 DOI: 10.1021/acsomega.3c02205] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 07/10/2023] [Indexed: 09/26/2023]
Abstract
Cyanobacteria have been studied in recent decades to investigate the principle mechanisms of plant-type oxygenic photosynthesis, as they are the inventors of this process, and their cultivation and research is much easier compared to land plants. Nevertheless, many cyanobacterial strains possess the capacity for at least some forms of heterotrophic growth. This review demonstrates that cyanobacteria are much more than simple photoautotrophs, and their flexibility toward different environmental conditions has been underestimated in the past. It summarizes the strains capable of heterotrophy known by date structured by their phylogeny and lists the possible substrates for heterotrophy for each of them in a table in the Supporting Information. The conditions are discussed in detail that cause heterotrophic growth for each strain in order to allow for reproduction of the results. The review explains the importance of this knowledge for the use of new methods of cyanobacterial cultivation, which may be advantageous under certain conditions. It seeks to stimulate other researchers to identify new strains capable of heterotrophy that have not been known so far.
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Affiliation(s)
- Ronald Stebegg
- Universität Wien, Fakultät für Chemie, Institut für
Biophysikalische Chemie, 1090 Wien, Austria
| | - Georg Schmetterer
- Universität Wien, Fakultät für Chemie, Institut für
Biophysikalische Chemie, 1090 Wien, Austria
| | - Annette Rompel
- Universität Wien, Fakultät für Chemie, Institut für
Biophysikalische Chemie, 1090 Wien, Austria
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8
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Tharasirivat V, Jantaro S. Increased Biomass and Polyhydroxybutyrate Production by Synechocystis sp. PCC 6803 Overexpressing RuBisCO Genes. Int J Mol Sci 2023; 24:ijms24076415. [PMID: 37047389 PMCID: PMC10094337 DOI: 10.3390/ijms24076415] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 03/20/2023] [Accepted: 03/26/2023] [Indexed: 03/31/2023] Open
Abstract
The overexpression of the RuBisCO (rbc) gene has recently become an achievable strategy for increasing cyanobacterial biomass and overcoming the biocompound production restriction. We successfully constructed two rbc-overexpressing Synechocystis sp. PCC 6803 strains (OX), including a strain overexpressing a large subunit of RuBisCO (OXrbcL) and another strain overexpressing all large, chaperone, and small subunits of RuBisCO (OXrbcLXS), resulting in higher and faster growth than wild type under sodium bicarbonate supplementation. This increased biomass of OX strains significantly contributed to the higher polyhydroxybutyrate (PHB) production induced by nutrient-deprived conditions, in particular nitrogen (N) and phosphorus (P). As a result of higher PHB contents in OX strains occurring at days 7 and 9 of nutrient deprivation, this enhancement was apparently made possible by cells preferentially maintaining their internal lipids while accumulating less glycogen. The OXrbcLXS strain, with the highest level of PHB at about 39 %w/dry cell weight (DCW) during 7 days of BG11-NP treatment, contained a lower glycogen level (31.9 %w/DCW) than wild type control (40 %w/DCW). In contrast, the wild type control strain exposed to N- and NP-stresses tended to retain lipid levels and store more glycogen than PHB. In this model, we, for the first time, implemented a RuBisCO-overexpressing cyanobacterial factory for overproducing PHB, destined for biofuel and biomaterial biotechnology.
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Chen AY, Ku JT, Tsai TP, Hung JJ, Hung BC, Lan EI. Metabolic Engineering Design Strategies for Increasing Carbon Fluxes Relevant for Biosynthesis in Cyanobacteria. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2023; 183:105-144. [PMID: 37093259 DOI: 10.1007/10_2023_218] [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: 04/25/2023]
Abstract
Cyanobacteria are promising microbial cell factories for the direct production of biochemicals and biofuels from CO2. Through genetic and metabolic engineering, they can be modified to produce a variety of both natural and non-natural compounds. To enhance the yield of these products, various design strategies have been developed. In this chapter, strategies used to enhance metabolic fluxes towards common precursors used in biosynthesis, including pyruvate, acetyl-CoA, malonyl-CoA, TCA cycle intermediates, and aromatics, are discussed. Additionally, strategies related to cofactor availability and mixotrophic conditions for bioproduction are also summarize.
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Affiliation(s)
- Arvin Y Chen
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu City, Taiwan
| | - Jason T Ku
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu City, Taiwan
| | - Teresa P Tsai
- Institute of Biomedical Engineering, National Yang Ming Chiao Tung University, Hsinchu City, Taiwan
| | - Jenny J Hung
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu City, Taiwan
| | - Billy C Hung
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu City, Taiwan
| | - Ethan I Lan
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu City, Taiwan.
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10
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Cui Y, Rasul F, Jiang Y, Zhong Y, Zhang S, Boruta T, Riaz S, Daroch M. Construction of an artificial consortium of Escherichia coli and cyanobacteria for clean indirect production of volatile platform hydrocarbons from CO2. Front Microbiol 2022; 13:965968. [PMID: 36338098 PMCID: PMC9635338 DOI: 10.3389/fmicb.2022.965968] [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: 06/10/2022] [Accepted: 09/23/2022] [Indexed: 11/29/2022] Open
Abstract
Ethylene and isoprene are essential platform chemicals necessary to produce polymers and materials. However, their current production methods based on fossil fuels are not very efficient and result in significant environmental pollution. For a successful transition more sustainable economic model, producing these key polymeric building blocks from renewable and sustainable resources such as biomass or CO2 is essential. Here, inspired by the symbiotic relationship of natural microbial communities, artificial consortia composed of E. coli strains producing volatile platform chemicals: ethylene and isoprene and two strains of cyanobacteria phototrophically synthesizing and exporting sucrose to feed these heterotrophs were developed. Disaccharide produced by transgenic cyanobacteria was used as a carbon and electron shuttle between the two community components. The E. coli cscB gene responsible for sucrose transport was inserted into two cyanobacterial strains, Thermosynechococcus elongatus PKUAC-SCTE542 and Synechococcus elongatus PCC7942, resulting in a maximal sucrose yield of 0.14 and 0.07 g/L, respectively. These organisms were co-cultured with E. coli BL21 expressing ethylene-forming enzyme or isoprene synthase and successfully synthesized volatile hydrocarbons. Productivity parameters of these co-cultures were higher than respective transgenic cultures of E. coli grown individually at similar sucrose concentrations, highlighting the positive impact of the artificial consortia on the production of these platform chemicals.
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Affiliation(s)
- Yixuan Cui
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Faiz Rasul
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Ying Jiang
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Yuqing Zhong
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Shanfa Zhang
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Tomasz Boruta
- Department of Bioprocess Engineering, Faculty of Process and Environmental Engineering, Lodz University of Technology, Lodz, Poland
| | - Sadaf Riaz
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Maurycy Daroch
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
- *Correspondence: Maurycy Daroch,
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11
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Tan LR, Cao YQ, Li JW, Xia PF, Wang SG. Transcriptomics and metabolomics of engineered Synechococcus elongatus during photomixotrophic growth. Microb Cell Fact 2022; 21:31. [PMID: 35248031 PMCID: PMC8897908 DOI: 10.1186/s12934-022-01760-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 02/22/2022] [Indexed: 12/18/2022] Open
Abstract
Background Converting carbon dioxide (CO2) into value-added chemicals using engineered cyanobacteria is a promising strategy to tackle the global warming and energy shortage issues. However, most cyanobacteria are autotrophic and use CO2 as a sole carbon source, which makes it hard to compete with heterotrophic hosts in either growth or productivity. One strategy to overcome this bottleneck is to introduce sugar utilization pathways to enable photomixotrophic growth with CO2 and sugar (e.g., glucose and xylose). Advances in engineering mixotrophic cyanobacteria have been obtained, while a systematic interrogation of these engineered strains is missing. This work aimed to fill the gap at omics level. Results We first constructed two engineered Synechococcus elongatus YQ2-gal and YQ3-xyl capable of utilizing glucose and xylose, respectively. To investigate the metabolic mechanism, transcriptomic and metabolomic analysis were then performed in the engineered photomixotrophic strains YQ2-gal and YQ3-xyl. Transcriptome and metabolome of wild-type S. elongatus were set as baselines. Increased abundance of metabolites in glycolysis or pentose phosphate pathway indicated that efficient sugar utilization significantly enhanced carbon flux in S. elongatus as expected. However, carbon flux was redirected in strain YQ2-gal as more flowed into fatty acids biosynthesis but less into amino acids. In strain YQ3-xyl, more carbon flux was directed into synthesis of sucrose, glucosamine and acetaldehyde, while less into fatty acids and amino acids. Moreover, photosynthesis and bicarbonate transport could be affected by upregulated genes, while nitrogen transport and assimilation were regulated by less transcript abundance of related genes in strain YQ3-xyl with utilization of xylose. Conclusions Our work identified metabolic mechanism in engineered S. elongatus during photomixotrophic growth, where regulations of fatty acids metabolism, photosynthesis, bicarbonate transport, nitrogen assimilation and transport are dependent on different sugar utilization. Since photomixotrophic cyanobacteria is regarded as a promising cell factory for bioproduction, this comprehensive understanding of metabolic mechanism of engineered S. elongatus during photomixotrophic growth would shed light on the engineering of more efficient and controllable bioproduction systems based on this potential chassis. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-022-01760-1.
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Yao J, Wang J, Ju Y, Dong Z, Song X, Chen L, Zhang W. Engineering a Xylose-Utilizing Synechococcus elongatus UTEX 2973 Chassis for 3-Hydroxypropionic Acid Biosynthesis under Photomixotrophic Conditions. ACS Synth Biol 2022; 11:678-688. [PMID: 35119824 DOI: 10.1021/acssynbio.1c00364] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Photomixotrophic cultivation of cyanobacteria is considered a promising strategy to achieve both high cell density and product accumulation, since cyanobacteria can obtain carbon and energy sources from organic matter in addition to those obtained from CO2 and sunlight. Acetyl coenzyme A (acetyl-CoA) is a key precursor used for the biosynthesis of a wide variety of important value-added chemicals. However, the acetyl-CoA content in cyanobacteria is typically low under photomixotrophic conditions, which limits the productivity of the derived chemicals. In this study, a xylose utilization pathway from Escherichia coli was first engineered into fast-growing Synechococcus elongatus UTEX 2973 (hereafter Synechococcus 2973), enabling the xylose based photomixotrophy. Metabolomics analysis of the engineered strain showed that the utilization of xylose enhanced the carbon flow to the oxidative pentose phosphate (OPP) pathway, along with an increase in the intracellular abundance of metabolites such as fructose-6-phosphate (F6P), fructose-1,6-bisphosphate (FBP), ribose-5-phosphate (R5P), erythrose-4-phosphate (E4P), and glyceraldehyde-3-phosphate (G3P). Then, the native glycolytic pathway was rewired via heterologous phosphoketolase (Pkt) gene expression, combined with phosphofructokinase (Pfk) gene knockout and fructose-1,6-bisphosphatase (Fbp) gene overexpression, to drive more carbon flux from xylose to acetyl-CoA. Finally, a heterologous 3-hydroxypropionic acid (3-HP) biosynthetic pathway was introduced. The results showed that 3-HP biosynthesis was improved by up to approximately 4.1-fold (from 22.5 mg/L to 91.3 mg/L) compared with the engineered strain without a rewired metabolism under photomixotrophic conditions and up to approximately 14-fold compared with the strain under photoautotrophic conditions. Using 3-HP as a "proof-of-molecule", our results demonstrated that this strategy could be applied to improve the intracellular pool of acetyl-CoA for the photomixotrophic production of value-added chemicals that require acetyl-CoA as a precursor in a cyanobacterial chassis.
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Affiliation(s)
- Jiaqi Yao
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, PR China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, PR China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, PR China
| | - Jin Wang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, PR China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, PR China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, PR China
| | - Yue Ju
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, PR China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, PR China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, PR China
| | - Zhengxin Dong
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, PR China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, PR China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, PR China
| | - Xinyu Song
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, PR China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, PR China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, PR China
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin 300072, PR China
| | - Lei Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, PR China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, PR China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, PR China
| | - Weiwen Zhang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, PR China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, PR China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, PR China
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin 300072, PR China
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Kallio P, Kugler A, Pyytövaara S, Stensjö K, Allahverdiyeva Y, Gao X, Lindblad P, Lindberg P. Photoautotrophic production of renewable ethylene by engineered cyanobacteria: Steering the cell metabolism towards biotechnological use. PHYSIOLOGIA PLANTARUM 2021; 173:579-590. [PMID: 33864400 DOI: 10.1111/ppl.13430] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 04/05/2021] [Accepted: 04/13/2021] [Indexed: 06/12/2023]
Abstract
Ethylene is a volatile hydrocarbon with a massive global market in the plastic industry. The ethylene now used for commercial applications is produced exclusively from nonrenewable petroleum sources, while competitive biotechnological production systems do not yet exist. This review focuses on the currently developed photoautotrophic bioproduction strategies that enable direct solar-driven conversion of CO2 into ethylene, based on the use of genetically engineered photosynthetic cyanobacteria expressing heterologous ethylene forming enzyme (EFE) from Pseudomonas syringae. The emphasis is on the different engineering strategies to express EFE and to direct the cellular carbon flux towards the primary metabolite 2-oxoglutarate, highlighting associated metabolic constraints, and technical considerations on cultivation strategies and conditional parameters. While the research field has progressed towards more robust strains with better production profiles, and deeper understanding of the associated metabolic limitations, it is clear that there is room for significant improvement to reach industrial relevance. At the same time, existing information and the development of synthetic biology tools for engineering cyanobacteria open new possibilities for improving the prospects for the sustainable production of renewable ethylene.
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Affiliation(s)
- Pauli Kallio
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, Finland
| | - Amit Kugler
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Uppsala, Sweden
| | - Samuli Pyytövaara
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, Finland
| | - Karin Stensjö
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Uppsala, Sweden
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, Finland
| | - Xiang Gao
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Uppsala, Sweden
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, China
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Uppsala, Sweden
| | - Pia Lindberg
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Uppsala, Sweden
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Song X, Diao J, Yao J, Cui J, Sun T, Chen L, Zhang W. Engineering a Central Carbon Metabolism Pathway to Increase the Intracellular Acetyl-CoA Pool in Synechocystis sp. PCC 6803 Grown under Photomixotrophic Conditions. ACS Synth Biol 2021; 10:836-846. [PMID: 33779148 DOI: 10.1021/acssynbio.0c00629] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In cyanobacteria, photomixotrophic growth is considered as a promising strategy to achieve both high cell density and product accumulation. However, the conversion of glucose to acetyl coenzyme A (acetyl-CoA) in the native glycolytic pathway is insufficient, which decreases the carbon utilization and productivity of engineered cyanobacteria under photomixotrophic conditions. To increase the carbon flux from glucose to key intracellular precursor acetyl-CoA in Synechocystis sp. PCC 6803 (hereafter, Synechocystis 6803) under photomixotrophic conditions, a synthetic nonoxidative cyclic glycolysis (NOG) pathway was introduced into the wild type strain, which successfully increased the intracellular pool of acetyl-CoA by approximately 1-fold. To minimize the competition for glucose, the native Embden-Meyerhof-Parnas (EMP) and Entner-Doudoroff (ED) pathways were knocked out, respectively. Notably, eliminating the native ED pathway in the engineered strain carrying the NOG pathway further increased the intracellular pool of acetyl-CoA up to 2.8-fold. Another carbon consuming pathway in Synechocystis 6803, the glycogen biosynthesis pathway, was additionally knocked out in the above-mentioned engineered strain, which enabled an increase of the intracellular acetyl-CoA pool by up to 3.5-fold when compared with the wild type strain. Finally, the content of intracellular lipids was analyzed as an index of the productive capacity of the engineered Synechocystis 6803 cell factory under photomixotrophic conditions. The results showed the total lipids yield increased about 26% compared to the wild type (from 15.71% to 34.12%, g/g glucose), demonstrating that this integrated approach could represent a general strategy not only for the improvement of the intracellular concentration of acetyl-CoA, but also for the production of value-added chemicals that require acetyl-CoA as a key precursor in cyanobacteria.
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Affiliation(s)
- Xinyu Song
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin 300072, People’s Republic of China
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People’s Republic of China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People’s Republic of China
- Law School of Tianjin University, Tianjin 300072, P.R. China
| | - Jinjin Diao
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People’s Republic of China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, People’s Republic of China
| | - Jiaqi Yao
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People’s Republic of China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, People’s Republic of China
| | - Jinyu Cui
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People’s Republic of China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, People’s Republic of China
| | - Tao Sun
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin 300072, People’s Republic of China
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People’s Republic of China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People’s Republic of China
- Law School of Tianjin University, Tianjin 300072, P.R. China
| | - Lei Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People’s Republic of China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, People’s Republic of China
| | - Weiwen Zhang
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin 300072, People’s Republic of China
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People’s Republic of China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People’s Republic of China
- Law School of Tianjin University, Tianjin 300072, P.R. China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, People’s Republic of China
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Genetic, Genomics, and Responses to Stresses in Cyanobacteria: Biotechnological Implications. Genes (Basel) 2021; 12:genes12040500. [PMID: 33805386 PMCID: PMC8066212 DOI: 10.3390/genes12040500] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/25/2021] [Accepted: 03/25/2021] [Indexed: 02/07/2023] Open
Abstract
Cyanobacteria are widely-diverse, environmentally crucial photosynthetic prokaryotes of great interests for basic and applied science. Work to date has focused mostly on the three non-nitrogen fixing unicellular species Synechocystis PCC 6803, Synechococcus PCC 7942, and Synechococcus PCC 7002, which have been selected for their genetic and physiological interests summarized in this review. Extensive "omics" data sets have been generated, and genome-scale models (GSM) have been developed for the rational engineering of these cyanobacteria for biotechnological purposes. We presently discuss what should be done to improve our understanding of the genotype-phenotype relationships of these models and generate robust and predictive models of their metabolism. Furthermore, we also emphasize that because Synechocystis PCC 6803, Synechococcus PCC 7942, and Synechococcus PCC 7002 represent only a limited part of the wide biodiversity of cyanobacteria, other species distantly related to these three models, should be studied. Finally, we highlight the need to strengthen the communication between academic researchers, who know well cyanobacteria and can engineer them for biotechnological purposes, but have a limited access to large photobioreactors, and industrial partners who attempt to use natural or engineered cyanobacteria to produce interesting chemicals at reasonable costs, but may lack knowledge on cyanobacterial physiology and metabolism.
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Wu M, Zhao X, Shen Y, Shi Z, Li G, Ma T. Efficient simultaneous utilization of glucose and xylose from corn straw by Sphingomonas sanxanigenens NX02 to produce microbial exopolysaccharide. BIORESOURCE TECHNOLOGY 2021; 319:124126. [PMID: 32971336 DOI: 10.1016/j.biortech.2020.124126] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 06/11/2023]
Abstract
Lignocellulosic biomass is a cheap and abundant carbon source in the microbial manufacturing industry. The native co-utilization of glucose and xylose from corn straw total hydrolysate (CSTH) by Sphingomonas sanxanigenens NX02 to produce exopolysaccharide Sanxan was investigated. Batch fermentation demonstrated that, compared to single sugar fermentation, co-substrate of glucose and xylose accelerated cell growth and Sanxan production in the initial 24 h with the same consumption rate. Additionally, NX02 converted CSTH into Sanxan with a yield of 13.10 ± 0.35 g/Kg, which is slightly higher than that of glucose fermentation. Coexistence of three xylose metabolic pathways (Xylose isomerase, Weimberg, and Dahms pathway), incomplete phosphoenolpyruvate-dependent phosphotransferase system, and reinforced fructose metabolism were recognized as the co-utilization mechanism through comparative transcriptome analysis. Therefore, strain NX02 has a prospect of becoming an attractive platform organism to produce polysaccharides and other bio-based products derived from agricultural waste hydrolysate rich in both glucose and xylose.
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Affiliation(s)
- Mengmeng Wu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Xin Zhao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yaqi Shen
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Zhuangzhuang Shi
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Guoqiang Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China; Tianjin Engineering Technology Center of Green Manufacturing Biobased Materials, Tianjin 300071, China.
| | - Ting Ma
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China; Tianjin Engineering Technology Center of Green Manufacturing Biobased Materials, Tianjin 300071, China.
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Ahuja V, Macho M, Ewe D, Singh M, Saha S, Saurav K. Biological and Pharmacological Potential of Xylitol: A Molecular Insight of Unique Metabolism. Foods 2020; 9:E1592. [PMID: 33147854 PMCID: PMC7693686 DOI: 10.3390/foods9111592] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 10/26/2020] [Accepted: 10/29/2020] [Indexed: 12/19/2022] Open
Abstract
Xylitol is a white crystalline, amorphous sugar alcohol and low-calorie sweetener. Xylitol prevents demineralization of teeth and bones, otitis media infection, respiratory tract infections, inflammation and cancer progression. NADPH generated in xylitol metabolism aid in the treatment of glucose-6-phosphate deficiency-associated hemolytic anemia. Moreover, it has a negligible effect on blood glucose and plasma insulin levels due to its unique metabolism. Its diverse applications in pharmaceuticals, cosmetics, food and polymer industries fueled its market growth and made it one of the top 12 bio-products. Recently, xylitol has also been used as a drug carrier due to its high permeability and non-toxic nature. However, it become a challenge to fulfil the rapidly increasing market demand of xylitol. Xylitol is present in fruit and vegetables, but at very low concentrations, which is not adequate to satisfy the consumer demand. With the passage of time, other methods including chemical catalysis, microbial and enzymatic biotransformation, have also been developed for its large-scale production. Nevertheless, large scale production still suffers from high cost of production. In this review, we summarize some alternative approaches and recent advancements that significantly improve the yield and lower the cost of production.
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Affiliation(s)
- Vishal Ahuja
- Department of Biotechnology, Himachal Pradesh University, Shimla 171005, India;
| | - Markéta Macho
- Laboratory of Algal Biotechnology—Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 37901 Třeboň, Czech Republic; (M.M.); (D.E.); (S.S.)
- Faculty of Science, University of South Bohemia, 37005 České Budějovice, Czech Republic
| | - Daniela Ewe
- Laboratory of Algal Biotechnology—Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 37901 Třeboň, Czech Republic; (M.M.); (D.E.); (S.S.)
| | - Manoj Singh
- Department of Biotechnology, Maharishi Markandeshwar (Deemed to be University), Mullana 133207, India;
| | - Subhasish Saha
- Laboratory of Algal Biotechnology—Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 37901 Třeboň, Czech Republic; (M.M.); (D.E.); (S.S.)
| | - Kumar Saurav
- Laboratory of Algal Biotechnology—Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 37901 Třeboň, Czech Republic; (M.M.); (D.E.); (S.S.)
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Fan ES, Lu KW, Wen RC, Shen CR. Photosynthetic Reduction of Xylose to Xylitol Using Cyanobacteria. Biotechnol J 2020; 15:e1900354. [PMID: 32388928 DOI: 10.1002/biot.201900354] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 04/30/2020] [Indexed: 12/13/2022]
Abstract
Photosynthetic generation of reducing power makes cyanobacteria an attractive host for biochemical reduction compared to cell-free and heterotrophic systems, which require burning of additional resources for the supply of reducing equivalent. Here, using xylitol synthesis as an example, efficient uptake and reduction of xylose photoautotrophically in Synechococcus elongatus PCC7942 are demonstrated upon introduction of an effective xylose transporter from Escherichia coli (Ec-XylE) and the NADPH-dependent xylose reductase from Candida boidinii (Cb-XR). Simultaneous activation of xylose uptake and matching of cofactor specificity enabled an average xylitol yield of 0.9 g g-1 xylose and a maximum productivity of about 0.15 g L-1 day-1 OD-1 with increased level of xylose supply. While long-term cellular maintenance still appears challenging, high-density conversion of xylose to xylitol using concentrated resting cell further pushes the titer of xylitol formation to 33 g L-1 in six days with 85% of maximum theoretical yield. While the results show that the unknown dissipation of xylose can be minimized when coupled to a strong reaction outlet, it remains to be the major hurdle hampering the yield despite the reported inability of cyanobacteria to metabolize xylose.
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Affiliation(s)
- Eric S Fan
- Department of Chemical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu, ROC 30013, Taiwan
| | - Ken W Lu
- Department of Chemical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu, ROC 30013, Taiwan
| | - Rex C Wen
- Department of Chemical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu, ROC 30013, Taiwan
| | - Claire R Shen
- Department of Chemical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu, ROC 30013, Taiwan
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Onyeabor M, Martinez R, Kurgan G, Wang X. Engineering transport systems for microbial production. ADVANCES IN APPLIED MICROBIOLOGY 2020; 111:33-87. [PMID: 32446412 DOI: 10.1016/bs.aambs.2020.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The rapid development in the field of metabolic engineering has enabled complex modifications of metabolic pathways to generate a diverse product portfolio. Manipulating substrate uptake and product export is an important research area in metabolic engineering. Optimization of transport systems has the potential to enhance microbial production of renewable fuels and chemicals. This chapter comprehensively reviews the transport systems critical for microbial production as well as current genetic engineering strategies to improve transport functions and thus production metrics. In addition, this chapter highlights recent advancements in engineering microbial efflux systems to enhance cellular tolerance to industrially relevant chemical stress. Lastly, future directions to address current technological gaps are discussed.
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Affiliation(s)
- Moses Onyeabor
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Rodrigo Martinez
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Gavin Kurgan
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Xuan Wang
- School of Life Sciences, Arizona State University, Tempe, AZ, United States.
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Lin WR, Tan SI, Hsiang CC, Sung PK, Ng IS. Challenges and opportunity of recent genome editing and multi-omics in cyanobacteria and microalgae for biorefinery. BIORESOURCE TECHNOLOGY 2019; 291:121932. [PMID: 31387837 DOI: 10.1016/j.biortech.2019.121932] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 07/26/2019] [Accepted: 07/27/2019] [Indexed: 06/10/2023]
Abstract
Microalgae and cyanobacteria are easy to culture, with higher growth rates and photosynthetic efficiencies compared to terrestrial plants, and thus generating higher productivity. The concept of microalgal biorefinery is to assimilate carbon dioxide and convert it to chemical energy/value-added products, such as vitamins, carotenoids, fatty acids, proteins and nucleic acids, to be applied in bioenergy, health foods, aquaculture feed, pharmaceutical and medical fields. Therefore, microalgae are annotated as the third generation feedstock in bioenergy and biorefinery. In past decades, many studies thrived to improve the carbon sequestration efficiency as well as enhance value-added compounds from different algae, especially via genetic engineering, synthetic biology, metabolic design and regulation. From the traditional Agrobacterium-mediated transformation DNA to novel CRISPR (clustered regularly interspaced short palindromic repeats) technology applied in microalgae and cyanobacteria, this review has highlighted the genome editing technology for biorefinery that is a highly environmental friendly trend to sustainable and renewable development.
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Affiliation(s)
- Way-Rong Lin
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC
| | - Shih-I Tan
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC
| | - Chuan-Chieh Hsiang
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC
| | - Po-Kuei Sung
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC.
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Carbonell V, Vuorio E, Aro EM, Kallio P. Enhanced stable production of ethylene in photosynthetic cyanobacterium Synechococcus elongatus PCC 7942. World J Microbiol Biotechnol 2019; 35:77. [PMID: 31069553 PMCID: PMC6536634 DOI: 10.1007/s11274-019-2652-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 04/26/2019] [Indexed: 11/26/2022]
Abstract
Ethylene is a volatile alkene which is used in large commercial scale as a precursor in plastic industry, and is currently derived from petroleum refinement. As an alternative production strategy, photoautotrophic cyanobacteria Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942 have been previously evaluated as potential biotechnological hosts for producing ethylene directly from CO2, by the over-expression of ethylene forming enzyme (efe) from Pseudomonas syringae. This work addresses various open questions related to the use of Synechococcus as the engineering target, and demonstrates long-term ethylene production at rates reaching 140 µL L−1 h−1 OD750−1 without loss of host vitality or capacity to produce ethylene. The results imply that the genetic instability observed earlier may be associated with the expression strategies, rather than efe over-expression, ethylene toxicity or the depletion of 2-oxoglutarate—derived cellular precursors in Synechococcus. In context with literature, this study underlines the critical differences in expression system design in the alternative hosts, and confirms Synechococcus as a suitable parallel host for further engineering.
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Affiliation(s)
- Veronica Carbonell
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun yliopisto, Finland
| | - Eerika Vuorio
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun yliopisto, Finland
| | - Eva-Mari Aro
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun yliopisto, Finland
| | - Pauli Kallio
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun yliopisto, Finland.
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Sawa N, Tatsuke T, Ogawa A, Hirokawa Y, Osanai T, Hanai T. Modification of carbon metabolism in Synechococcus elongatus PCC 7942 by cyanophage-derived sigma factors for bioproduction improvement. J Biosci Bioeng 2019; 127:256-264. [DOI: 10.1016/j.jbiosc.2018.07.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 07/20/2018] [Accepted: 07/23/2018] [Indexed: 12/15/2022]
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Sun T, Li S, Song X, Diao J, Chen L, Zhang W. Toolboxes for cyanobacteria: Recent advances and future direction. Biotechnol Adv 2018; 36:1293-1307. [DOI: 10.1016/j.biotechadv.2018.04.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/09/2018] [Accepted: 04/26/2018] [Indexed: 12/20/2022]
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Photomixotrophic chemical production in cyanobacteria. Curr Opin Biotechnol 2018; 50:65-71. [DOI: 10.1016/j.copbio.2017.11.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/11/2017] [Accepted: 11/13/2017] [Indexed: 11/19/2022]
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25
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Tailoring cyanobacterial cell factory for improved industrial properties. Biotechnol Adv 2018; 36:430-442. [DOI: 10.1016/j.biotechadv.2018.01.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 01/07/2018] [Accepted: 01/08/2018] [Indexed: 11/20/2022]
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26
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Woo HM. Metabolic pathway rewiring in engineered cyanobacteria for solar-to-chemical and solar-to-fuel production from CO 2. Bioengineered 2018; 9:2-5. [PMID: 28430539 PMCID: PMC5972923 DOI: 10.1080/21655979.2017.1317572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Photoautotrophic cyanobacteria have been developed to convert CO2 to valuable chemicals and fuels as solar-to-chemical (S2C) and solar-to-fuel (S2F) platforms. Here, I describe the rewiring of the metabolic pathways in cyanobacteria to better understand the endogenous carbon flux and to enhance the yield of heterologous products. The plasticity of the cyanobacterial metabolism has been proposed to be advantageous for the development of S2C and S2F processes. The rewiring of the sugar catabolism and of the phosphoketolase pathway in the central cyanobacterial metabolism allowed for an enhancement in the level of target products by redirecting the carbon fluxes. Thus, metabolic pathway rewiring can promote the development of more efficient cyanobacterial cell factories for the generation of feasible S2C and S2F platforms.
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Affiliation(s)
- Han Min Woo
- a Department of Food Science and Biotechnology , Sungkyunkwan University (SKKU) , Jangan-gu, Suwon , Republic of Korea
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Hirokawa Y, Matsuo S, Hamada H, Matsuda F, Hanai T. Metabolic engineering of Synechococcus elongatus PCC 7942 for improvement of 1,3-propanediol and glycerol production based on in silico simulation of metabolic flux distribution. Microb Cell Fact 2017; 16:212. [PMID: 29178875 PMCID: PMC5702090 DOI: 10.1186/s12934-017-0824-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 11/13/2017] [Indexed: 12/22/2022] Open
Abstract
Background Production directly from carbon dioxide by engineered cyanobacteria is one of the promising technologies for sustainable future. Previously, we have successfully achieved 1,3-propanediol (1,3-PDO) production using Synechococcus elongatus PCC 7942 with a synthetic metabolic pathway. The strain into which the synthetic metabolic pathway was introduced produced 3.48 mM (0.265 g/L) 1,3-PDO and 14.3 mM (1.32 g/L) glycerol during 20 days of incubation. In this study, the productivities of 1,3-PDO were improved by gene disruption selected by screening with in silico simulation. Methods First, a stoichiometric metabolic model was applied to prediction of cellular metabolic flux distribution in a 1,3-PDO-producing strain of S. elongatus PCC 7942. A genome-scale model of S. elongatus PCC 7942 constructed by Knoop was modified by the addition of a synthetic metabolic pathway for 1,3-PDO production. Next, the metabolic flux distribution predicted by metabolic flux balance analysis (FBA) was used for in silico simulation of gene disruption. As a result of gene disruption simulation, NADPH dehydrogenase 1 (NDH-1) complexes were found by screening to be the most promising candidates for disruption to improve 1,3-PDO production. The effect of disruption of the gene encoding a subunit of the NDH-1 complex was evaluated in the 1,3-PDO-producing strain. Results and Conclusions During 20 days of incubation, the ndhF1-null 1,3-PDO-producing strain showed the highest titers: 4.44 mM (0.338 g/L) 1,3-PDO and 30.3 mM (2.79 g/L) glycerol. In this study, we successfully improved 1,3-PDO productivity on the basis of in silico simulation of gene disruption. Electronic supplementary material The online version of this article (10.1186/s12934-017-0824-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yasutaka Hirokawa
- Laboratory for Bioinformatics, Graduate School of Systems Biosciences, Kyushu University, 804 Westwing, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Shingo Matsuo
- Laboratory for Bioinformatics, Graduate School of Systems Biosciences, Kyushu University, 804 Westwing, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Hiroyuki Hamada
- Laboratory for Bioinformatics, Graduate School of Systems Biosciences, Kyushu University, 804 Westwing, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Fumio Matsuda
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Taizo Hanai
- Laboratory for Bioinformatics, Graduate School of Systems Biosciences, Kyushu University, 804 Westwing, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
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Singh R, Parihar P, Singh M, Bajguz A, Kumar J, Singh S, Singh VP, Prasad SM. Uncovering Potential Applications of Cyanobacteria and Algal Metabolites in Biology, Agriculture and Medicine: Current Status and Future Prospects. Front Microbiol 2017; 8:515. [PMID: 28487674 PMCID: PMC5403934 DOI: 10.3389/fmicb.2017.00515] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 03/13/2017] [Indexed: 12/05/2022] Open
Abstract
Cyanobacteria and algae having complex photosynthetic systems can channelize absorbed solar energy into other forms of energy for production of food and metabolites. In addition, they are promising biocatalysts and can be used in the field of "white biotechnology" for enhancing the sustainable production of food, metabolites, and green energy sources such as biodiesel. In this review, an endeavor has been made to uncover the significance of various metabolites like phenolics, phytoene/terpenoids, phytols, sterols, free fatty acids, photoprotective compounds (MAAs, scytonemin, carotenoids, polysaccharides, halogenated compounds, etc.), phytohormones, cyanotoxins, biocides (algaecides, herbicides, and insecticides) etc. Apart from this, the importance of these metabolites as antibiotics, immunosuppressant, anticancer, antiviral, anti-inflammatory agent has also been discussed. Metabolites obtained from cyanobacteria and algae have several biotechnological, industrial, pharmaceutical, and cosmetic uses which have also been discussed in this review along with the emerging technology of their harvesting for enhancing the production of compounds like bioethanol, biofuel etc. at commercial level. In later sections, we have discussed genetically modified organisms and metabolite production from them. We have also briefly discussed the concept of bioprocessing highlighting the functioning of companies engaged in metabolites production as well as their cost effectiveness and challenges that are being addressed by these companies.
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Affiliation(s)
- Rachana Singh
- Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of AllahabadAllahabad, India
| | - Parul Parihar
- Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of AllahabadAllahabad, India
| | - Madhulika Singh
- Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of AllahabadAllahabad, India
| | - Andrzej Bajguz
- Faculty of Biology and Chemistry, Institute of Biology, University of BialystokBialystok, Poland
| | - Jitendra Kumar
- Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of AllahabadAllahabad, India
| | - Samiksha Singh
- Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of AllahabadAllahabad, India
| | - Vijay P. Singh
- Department of Botany, Govt. Ramanuj Pratap Singhdev Post-Graduate CollegeBaikunthpur, Koriya, India
| | - Sheo M. Prasad
- Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of AllahabadAllahabad, India
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Construction of a novel d-lactate producing pathway from dihydroxyacetone phosphate of the Calvin cycle in cyanobacterium, Synechococcus elongatus PCC 7942. J Biosci Bioeng 2017; 124:54-61. [PMID: 28325659 DOI: 10.1016/j.jbiosc.2017.02.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 02/23/2017] [Accepted: 02/23/2017] [Indexed: 01/10/2023]
Abstract
Using engineered cyanobacteria to produce various chemicals from carbon dioxide is a promising technology for a sustainable future. Lactate is a valuable commodity that can be used for the biodegradable plastic, polylactic acid. Typically, lactate production using engineered cyanobacteria was via the conversion of pyruvate in glycolysis by lactate dehydrogenase. In cyanobacteria, the metabolic flux in the Calvin cycle is higher than that in glycolysis under photoautotrophic conditions. The construction of a novel lactate producing pathway that uses metabolites from the Calvin cycle could potentially increase lactate productivity in cyanobacteria. In order to develop such a novel lactate production pathway, we engineered a cyanobacterium Synechococcus elongatus PCC 7942 strain that produced lactate directly from carbon dioxide using dihydroxyacetone phosphate (DHAP) via methylglyoxal. We confirmed that wild-type strain of S. elongatus PCC 7942 could produce lactate using exogenous methylglyoxal. A methylglyoxal synthase gene, mgsA, from Escherichia coli was introduced into Synechococcus elongates PCC 7942 for conversion of DHAP to methylglyoxal. This engineered strain produced lactate directly from carbon dioxide. Genes encoding intrinsic putative glyoxalase I, II (Synpcc7942_0638, 1403) and the lactate/H+ symporter from E. coli (lldP) were additionally introduced to enhance the production. For higher lactate production, it was important to maintain elevated extracellular pH due to the characteristics of lactate exporting system. In this study, the highest lactate titer of 13.7 mM (1.23 g/l) was achieved during a 24-day incubation with the engineered S. elongatus PCC 7942 strain possessing the novel lactate producing pathway.
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30
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Kanno M, Atsumi S. Engineering an Obligate Photoautotrophic Cyanobacterium to Utilize Glycerol for Growth and Chemical Production. ACS Synth Biol 2017; 6:69-75. [PMID: 27643408 DOI: 10.1021/acssynbio.6b00239] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cyanobacteria have attracted much attention as a means to directly recycle carbon dioxide into valuable chemicals that are currently produced from petroleum. However, the titers and productivities achieved are still far below the level required in industry. To make a more industrially applicable production scheme, glycerol, a byproduct of biodiesel production, can be used as an additional carbon source for photomixotrophic chemical production. Glycerol is an ideal candidate due to its availability and low cost. In this study, we found that a heterologous glycerol respiratory pathway enabled Synechococcus elongatus PCC 7942 to utilize extracellular glycerol. The engineered strain produced 761 mg/L of 2,3-butanediol in 48 h with a 290% increase over the control strain under continuous light conditions. Glycerol supplementation also allowed for continuous cell growth and 2,3-butanediol production in diurnal light conditions. These results highlight the potential of glycerol as an additional carbon source for photomixotrophic chemical production in cyanobacteria.
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Affiliation(s)
- Masahiro Kanno
- Department
of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
- Asahi Kasei Corporation, 2-1
Samejima, Fuji, Shizuoka 416-8501, Japan
| | - Shota Atsumi
- Department
of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
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31
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Woo HM. Solar-to-chemical and solar-to-fuel production from CO 2 by metabolically engineered microorganisms. Curr Opin Biotechnol 2017; 45:1-7. [PMID: 28088091 DOI: 10.1016/j.copbio.2016.11.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 11/16/2016] [Accepted: 11/23/2016] [Indexed: 01/01/2023]
Abstract
Recent development of carbon capture utilization (CCU) for reduction of greenhouse gas emission are reviewed. In the case of CO2 utilization, I describe development of solar-to-chemical and solar-to-fuel technology that refers to the use of solar energy to convert CO2 to desired chemicals and fuels. Photoautotrophic cyanobacterial platforms have been extensively developed on this principle, producing a diverse range of alcohols, organic acids, and isoprenoids directly from CO2. Recent breakthroughs in the metabolic engineering of cyanobacteria were reviewed. In addition, adoption of the light harvesting mechanisms from nature, photovoltaics-derived water splitting technologies have recently been integrated with microbial biotechnology to produce desired chemicals. Studies on the integration of electrode material with next-generation microbes are showcased for alternative solar-to-chemical and solar-to-fuel platforms.
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Affiliation(s)
- Han Min Woo
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea.
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Improvement of 1,3-propanediol production using an engineered cyanobacterium, Synechococcus elongatus by optimization of the gene expression level of a synthetic metabolic pathway and production conditions. Metab Eng 2017; 39:192-199. [DOI: 10.1016/j.ymben.2016.12.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/08/2016] [Accepted: 12/05/2016] [Indexed: 11/17/2022]
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33
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Xie M, Wang W, Zhang W, Chen L, Lu X. Versatility of hydrocarbon production in cyanobacteria. Appl Microbiol Biotechnol 2016; 101:905-919. [DOI: 10.1007/s00253-016-8064-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 12/07/2016] [Accepted: 12/10/2016] [Indexed: 10/20/2022]
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34
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Cyanobacterial metabolic engineering for biofuel and chemical production. Curr Opin Chem Biol 2016; 35:43-50. [DOI: 10.1016/j.cbpa.2016.08.023] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 08/22/2016] [Accepted: 08/24/2016] [Indexed: 11/21/2022]
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35
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Case AE, Atsumi S. Cyanobacterial chemical production. J Biotechnol 2016; 231:106-114. [DOI: 10.1016/j.jbiotec.2016.05.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 05/19/2016] [Indexed: 01/03/2023]
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36
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McEwen JT, Kanno M, Atsumi S. 2,3 Butanediol production in an obligate photoautotrophic cyanobacterium in dark conditions via diverse sugar consumption. Metab Eng 2016; 36:28-36. [DOI: 10.1016/j.ymben.2016.03.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 02/14/2016] [Accepted: 03/11/2016] [Indexed: 10/22/2022]
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Ranade S, Zhang Y, Kaplan M, Majeed W, He Q. Metabolic Engineering and Comparative Performance Studies of Synechocystis sp. PCC 6803 Strains for Effective Utilization of Xylose. Front Microbiol 2015; 6:1484. [PMID: 26732758 PMCID: PMC4689873 DOI: 10.3389/fmicb.2015.01484] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 12/09/2015] [Indexed: 01/16/2023] Open
Abstract
Wood sugars such as xylose can be used as an inexpensive carbon source for biotechnological applications. The model cyanobacterium Synechocystis sp. PCC 6803 lacks the ability to catabolize wood sugars as an energy source. Here, we generated four Synechocystis strains that heterologously expressed XylAB enzymes, which mediate xylose catabolism, either in combination with or without one of three xylose transporters, namely XylE, GalP, or Glf. Except for glf, which is derived from the bacterium Zymomonas mobilis ZM4, the heterologous genes were sourced from Escherichia coli K-12. All of the recombinant strains were able to utilize xylose in the absence of catabolite repression. When xylose was the lone source of organic carbon, strains possessing the XylE and Glf transporters were most efficient in terms of dry biomass production and xylose consumption and the strain lacking a heterologous transporter was the least efficient. However, in the presence of a xylose-glucose mixed sugar source, the strains exhibited similar levels of growth and xylose consumption. This study demonstrates that various bacterial xylose transporters can boost xylose catabolism in transgenic Synechocystis strains, and paves the way for the sustainable production of bio-compounds and green fuels from lignocellulosic biomass.
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Affiliation(s)
- Saurabh Ranade
- Department of Biology, University of Arkansas at Little Rock Little Rock, AR, USA
| | - Yan Zhang
- Biotechnology Research Center, Shandong Academy of Agricultural Sciences Jinan, China
| | - Mecit Kaplan
- Department of Biology, University of Arkansas at Little Rock Little Rock, AR, USA
| | - Waqar Majeed
- Center for Integrative Nanotechnology Sciences, University of Arkansas at Little Rock Little Rock, AR, USA
| | - Qingfang He
- Department of Biology, University of Arkansas at Little Rock Little Rock, AR, USA
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Xiong W, Lee TC, Rommelfanger S, Gjersing E, Cano M, Maness PC, Ghirardi M, Yu J. Phosphoketolase pathway contributes to carbon metabolism in cyanobacteria. NATURE PLANTS 2015; 2:15187. [PMID: 27250745 DOI: 10.1038/nplants.2015.187] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 10/30/2015] [Indexed: 05/20/2023]
Abstract
Central carbon metabolism in cyanobacteria comprises the Calvin-Benson-Bassham (CBB) cycle, glycolysis, the pentose phosphate (PP) pathway and the tricarboxylic acid (TCA) cycle. Redundancy in this complex metabolic network renders the rational engineering of cyanobacterial metabolism for the generation of biomass, biofuels and chemicals a challenge. Here we report the presence of a functional phosphoketolase pathway, which splits xylulose-5-phosphate (or fructose-6-phosphate) to acetate precursor acetyl phosphate, in an engineered strain of the model cyanobacterium Synechocystis (ΔglgC/xylAB), in which glycogen synthesis is blocked, and xylose catabolism enabled through the introduction of xylose isomerase and xylulokinase. We show that this mutant strain is able to metabolise xylose to acetate on nitrogen starvation. To see whether acetate production in the mutant is linked to the activity of phosphoketolase, we disrupted a putative phosphoketolase gene (slr0453) in the ΔglgC/xylAB strain, and monitored metabolic flux using (13)C labelling; acetate and 2-oxoglutarate production was reduced in the light. A metabolic flux analysis, based on isotopic data, suggests that the phosphoketolase pathway metabolises over 30% of the carbon consumed by ΔglgC/xylAB during photomixotrophic growth on xylose and CO2. Disruption of the putative phosphoketolase gene in wild-type Synechocystis also led to a deficiency in acetate production in the dark, indicative of a contribution of the phosphoketolase pathway to heterotrophic metabolism. We suggest that the phosphoketolase pathway, previously uncharacterized in photosynthetic organisms, confers flexibility in energy and carbon metabolism in cyanobacteria, and could be exploited to increase the efficiency of cyanobacterial carbon metabolism and photosynthetic productivity.
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Affiliation(s)
- Wei Xiong
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA
| | - Tai-Chi Lee
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA
| | - Sarah Rommelfanger
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA
| | - Erica Gjersing
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA
| | - Melissa Cano
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA
| | - Pin-Ching Maness
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA
| | - Maria Ghirardi
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA
| | - Jianping Yu
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA
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Advances in Metabolic Engineering of Cyanobacteria for Photosynthetic Biochemical Production. Metabolites 2015; 5:636-58. [PMID: 26516923 PMCID: PMC4693188 DOI: 10.3390/metabo5040636] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/30/2015] [Accepted: 10/22/2015] [Indexed: 11/19/2022] Open
Abstract
Engineering cyanobacteria into photosynthetic microbial cell factories for the production of biochemicals and biofuels is a promising approach toward sustainability. Cyanobacteria naturally grow on light and carbon dioxide, bypassing the need of fermentable plant biomass and arable land. By tapping into the central metabolism and rerouting carbon flux towards desirable compound production, cyanobacteria are engineered to directly convert CO2 into various chemicals. This review discusses the diversity of bioproducts synthesized by engineered cyanobacteria, the metabolic pathways used, and the current engineering strategies used for increasing their titers.
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