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Chang J, Shi X, Kim M, Lee ME, Han SO. Enhancing Phycocyanobilin Production Efficiency in Engineered Corynebacterium glutamicum: Strategies and Potential Application. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:12219-12228. [PMID: 38747135 DOI: 10.1021/acs.jafc.4c02306] [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: 05/30/2024]
Abstract
Phycocyanobilin, an algae-originated light-harvesting pigment known for its antioxidant properties, has gained attention as it plays important roles in the food and medication industries and has surged in demand owing to its low-yield extraction from natural resources. In this study, engineered Corynebacterium glutamicum was developed to achieve high PCB production, and three strategies were proposed: reinforcement of the heme biosynthesis pathway with the introduction of two PCB-related enzymes, strengthening of the pentose phosphate pathway to generate an efficient cycle of NADPH, and fed-batch fermentation to maximize PCB production. Each approach increased PCB synthesis, and the final engineered strain successfully produced 78.19 mg/L in a flask and 259.63 mg/L in a 5 L bioreactor, representing the highest bacterial production of PCB reported to date, to our knowledge. The strategies applied in this study will be useful for the synthesis of PCB derivatives and can be applied in the food and pharmaceutical industries.
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Affiliation(s)
- Joonhee Chang
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Xiaoyu Shi
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Minhye Kim
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Myeong-Eun Lee
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
- Institute of Life Science and Natural Resources, Korea University, Seoul 02841, Republic of Korea
| | - Sung Ok Han
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
- Institute of Life Science and Natural Resources, Korea University, Seoul 02841, Republic of Korea
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Ko YJ, Lee ME, Cho BH, Kim M, Hyeon JE, Han JH, Han SO. Bioproduction of porphyrins, phycobilins, and their proteins using microbial cell factories: engineering, metabolic regulations, challenges, and perspectives. Crit Rev Biotechnol 2024; 44:373-387. [PMID: 36775664 DOI: 10.1080/07388551.2023.2168512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/21/2022] [Accepted: 01/03/2023] [Indexed: 02/14/2023]
Abstract
Porphyrins, phycobilins, and their proteins have abundant π-electrons and strongly absorb visible light, some of which bind a metal ion in the center. Because of the structural and optical properties, they not only play critical roles as an essential component in natural systems but also have attracted much attention as a high value specialty chemical in various fields, including renewable energy, cosmetics, medicines, and foods. However, their commercial application seems to be still limited because the market price of porphyrins and phycobilins is generally expensive to apply them easily. Furthermore, their petroleum-based chemical synthesis is energy-intensive and emits a pollutant. Recently, to replace petroleum-based production, many studies on the bioproduction of metalloporphyrins, including Zn-porphyrin, Co-porphyrin, and heme, porphyrin derivatives including chlorophyll, biliverdin, and phycobilins, and their proteins including hemoproteins, phycobiliproteins, and phytochromes from renewable carbon sources using microbial cell factories have been reported. This review outlines recent advances in the bioproduction of porphyrins, phycobilins, and their proteins using microbial cell factories developed by various microbial biotechnology techniques, provides well-organized information on metabolic regulations of the porphyrin metabolism, and then critically discusses challenges and future perspectives. Through these, it is expected to be able to achieve possible solutions and insights and to develop an outstanding platform to be applied to the industry in future research.
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Affiliation(s)
- Young Jin Ko
- Department of Biotechnology, Korea University, Seoul, Republic of Korea
- Institute of Life Science and Natural Resources, Korea University, Seoul, Korea
| | - Myeong-Eun Lee
- Department of Biotechnology, Korea University, Seoul, Republic of Korea
| | - Byeong-Hyeon Cho
- Department of Biotechnology, Korea University, Seoul, Republic of Korea
| | - Minhye Kim
- Department of Biotechnology, Korea University, Seoul, Republic of Korea
| | - Jeong Eun Hyeon
- Department of Next Generation Applied Sciences, The Graduate School of Sungshin University, Seoul, Korea
- Department of Food Science and Biotechnology, College of Knowledge-Based Services Engineering, Sungshin Women's University, Seoul, Korea
| | - Joo Hee Han
- Department of Next Generation Applied Sciences, The Graduate School of Sungshin University, Seoul, Korea
- Department of Food Science and Biotechnology, College of Knowledge-Based Services Engineering, Sungshin Women's University, Seoul, Korea
| | - Sung Ok Han
- Department of Biotechnology, Korea University, Seoul, Republic of Korea
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Li X, Hou W, Lei J, Chen H, Wang Q. The Unique Light-Harvesting System of the Algal Phycobilisome: Structure, Assembly Components, and Functions. Int J Mol Sci 2023; 24:ijms24119733. [PMID: 37298688 DOI: 10.3390/ijms24119733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 05/30/2023] [Accepted: 06/02/2023] [Indexed: 06/12/2023] Open
Abstract
The phycobilisome (PBS) is the major light-harvesting apparatus in cyanobacteria and red algae. It is a large multi-subunit protein complex of several megadaltons that is found on the stromal side of thylakoid membranes in orderly arrays. Chromophore lyases catalyse the thioether bond between apoproteins and phycobilins of PBSs. Depending on the species, composition, spatial assembly, and, especially, the functional tuning of different phycobiliproteins mediated by linker proteins, PBSs can absorb light between 450 and 650 nm, making them efficient and versatile light-harvesting systems. However, basic research and technological innovations are needed, not only to understand their role in photosynthesis but also to realise the potential applications of PBSs. Crucial components including phycobiliproteins, phycobilins, and lyases together make the PBS an efficient light-harvesting system, and these provide a scheme to explore the heterologous synthesis of PBS. Focusing on these topics, this review describes the essential components needed for PBS assembly, the functional basis of PBS photosynthesis, and the applications of phycobiliproteins. Moreover, key technical challenges for heterologous biosynthesis of phycobiliproteins in chassis cells are discussed.
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Affiliation(s)
- Xiang Li
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Wenwen Hou
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Jiaxi Lei
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Hui Chen
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Qiang Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
- Academy for Advanced Interdisciplinary Studies, Henan University, Kaifeng 475001, China
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Chen H, Qi H, Xiong P. Phycobiliproteins-A Family of Algae-Derived Biliproteins: Productions, Characterization and Pharmaceutical Potentials. Mar Drugs 2022; 20:md20070450. [PMID: 35877743 PMCID: PMC9318637 DOI: 10.3390/md20070450] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/26/2022] [Accepted: 06/27/2022] [Indexed: 12/04/2022] Open
Abstract
Phycobiliproteins (PBPs) are colored and water-soluble biliproteins found in cyanobacteria, rhodophytes, cryptomonads and cyanelles. They are divided into three main types: allophycocyanin, phycocyanin and phycoerythrin, according to their spectral properties. There are two methods for PBPs preparation. One is the extraction and purification of native PBPs from Cyanobacteria, Cryptophyta and Rhodophyta, and the other way is the production of recombinant PBPs by heterologous hosts. Apart from their function as light-harvesting antenna in photosynthesis, PBPs can be used as food colorants, nutraceuticals and fluorescent probes in immunofluorescence analysis. An increasing number of reports have revealed their pharmaceutical potentials such as antioxidant, anti-tumor, anti-inflammatory and antidiabetic effects. The advances in PBP biogenesis make it feasible to construct novel PBPs with various activities and produce recombinant PBPs by heterologous hosts at low cost. In this review, we present a critical overview on the productions, characterization and pharmaceutical potentials of PBPs, and discuss the key issues and future perspectives on the exploration of these valuable proteins.
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Affiliation(s)
- Huaxin Chen
- School of Life Sciences and Medicine, Shandong University of Technology, Zibo 255000, China;
- Correspondence:
| | - Hongtao Qi
- School of Life Sciences, Qingdao University, Qingdao 266000, China;
| | - Peng Xiong
- School of Life Sciences and Medicine, Shandong University of Technology, Zibo 255000, China;
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The Bioactivities of Phycocyanobilin from Spirulina. J Immunol Res 2022; 2022:4008991. [PMID: 35726224 PMCID: PMC9206584 DOI: 10.1155/2022/4008991] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 06/06/2022] [Indexed: 11/18/2022] Open
Abstract
Phycocyanobilin (PCB) is a linear open-chain tetrapyrrole chromophore that captures and senses light and a variety of biological activities, such as anti-oxidation, anti-cancer, and anti-inflammatory. In this paper, the biological activities of PCB are reviewed, and the related mechanism of PCB and its latest application in disease treatment are introduced. PCB can resist oxidation by scavenging free radicals, inhibiting the activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, and delaying the activity of antioxidant enzymes. In addition, PCB can also be used as an excellent anti-inflammatory agent to reduce the proinflammatory factors IL-6 and IFN-γ and to up-regulate the production of anti-inflammatory cytokine IL-10 by inhibiting the inflammatory signal pathways NF-κB and mitogen-activated protein kinase (MAPK). Due to the above biological activities of phycocyanobilin PCB, it is expected to become a new effective drug for treating various diseases, such as COVID-19 complications, atherosclerosis, multiple sclerosis (MS), and ischaemic stroke (IS).
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Zhao X, Gao H, Wang Y, Wang Z, Zhou J. Efficient Synthesis of Phycocyanobilin by Combinatorial Metabolic Engineering in Escherichia coli. ACS Synth Biol 2022; 11:2089-2097. [PMID: 35580338 DOI: 10.1021/acssynbio.2c00016] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Phycocyanobilin (PCB) is a kind of light-harvesting pigment which naturally exists in algae and plays important roles in absorbing and transferring energy. Based on its antioxidant and optical properties, PCB has been applied in food, medicine, and cosmetics. Currently, PCB is mainly extracted from Spirulina through complicated steps; thus, the biosynthesis of PCB in Escherichia coli has attracted more attention. However, due to the lower catalytic efficiency of synthetic enzymes and the deficiency of precursors and cofactors, the titer of PCB remains at a low level. Here, we report the efficient synthesis of PCB by the expression of heme oxygenase-1 from Thermosynechococcus elongatus and PCB: ferredoxin oxidoreductase (PcyA) from Synechocystis sp. using a high-copy number plasmid with an inducible T7lac promoter and the assembly of these two enzymes at a suitable ratio of 2:1 with DNA scaffolds. Additionally, the synthesis of PCB was further enhanced by direct supplementation of 5-aminolevulinic acid (ALA), moderate overexpression of key enzymes in the heme biosynthetic pathway (hemB and hemH), and accelerated cycle of cofactors (NADPH) through the expression of NAD+ kinase and the addition of a reducing agent. Finally, based on the optimal conditions (Modified R medium with 200 mg/L ALA, 20 mg/L FeSO4·7H2O, and 5 g/L vitamin C induced by 0.8 mM isopropylthio-β-galactoside at 30 °C), the highest reported titer of PCB (28.32 mg/L) was obtained at the fermenter level by feeding glucose and FeSO4·7H2O. The strategies applied in this study will be useful for the synthesis of other natural pigments and PCB or heme derivatives in E. coli.
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Affiliation(s)
- Xinrui Zhao
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
- Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Haixin Gao
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
- Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Yuqi Wang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
- Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Ziwei Wang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
- Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Jingwen Zhou
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
- Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
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Optogenetic tools for microbial synthetic biology. Biotechnol Adv 2022; 59:107953. [DOI: 10.1016/j.biotechadv.2022.107953] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/09/2022] [Accepted: 04/04/2022] [Indexed: 12/22/2022]
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Raghavan AR, Salim K, Yadav VG. Optogenetic Control of Heterologous Metabolism in E. coli. ACS Synth Biol 2020; 9:2291-2300. [PMID: 32786352 DOI: 10.1021/acssynbio.9b00454] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Multiobjective optimization of microbial chassis for the production of xenobiotic compounds requires the implementation of metabolic control strategies that permit dynamic distribution of cellular resources between biomass and product formation. We addressed this need in a previous study by engineering the T7 RNA polymerase to be thermally responsive. The modified polymerase is activated only after the temperature of the host cell falls below 18 °C, and Escherichia coli cells that employ the protein to transcribe the heterologous lycopene biosynthetic pathway exhibit impressive improvements in productivity. We have expanded our toolbox of metabolic switches in the current study by engineering a version of the T7 RNA polymerase that drives the transition between biomass and product formation upon stimulation with red light. The engineered polymerase is expressed as two distinct polypeptide chains. Each chain comprises one of two photoactive components from Arabidopsis thaliana, phytochrome B (PhyB) and phytochrome-integrating factor 3 (PIF3), as well as the N- or C-terminus domains of both, the vacuolar ATPase subunit (VMA) intein of Saccharomyces cerevisiae and the polymerase. Red light drives photodimerization of PhyB and PIF3, which then brings together the N- and C-terminus domains of the VMA intein. Trans-splicing of the intein follows suit and produces an active form of the polymerase that subsequently transcribes any sequence that is under the control of a T7 promoter. The photodimerization also involves a third element, the cyanobacterial chromophore phycocyanobilin (PCB), which too is expressed heterologously by E. coli. We deployed this version of the T7 RNA polymerase to control the production of lycopene in E. coli and observed tight control of pathway expression. We tested a variety of expression configurations to identify one that imposes the lowest metabolic burden on the strain, and we subsequently optimized key parameters such as the source, moment, and duration of photostimulation. We also identified targets for future refinement of the circuit. In summary, our work is a significant advance for the field and greatly expands on previous work by other groups that have used optogenetic circuits to control heterologous metabolism in prokaryotic hosts.
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Affiliation(s)
- Adhithi R. Raghavan
- Department of Chemical and Biological Engineering & School of Biomedical Engineering, The University of British Columbia, Vancouver, V6T 1Z3, Canada
| | - Kevin Salim
- Department of Chemical and Biological Engineering & School of Biomedical Engineering, The University of British Columbia, Vancouver, V6T 1Z3, Canada
| | - Vikramaditya G. Yadav
- Department of Chemical and Biological Engineering & School of Biomedical Engineering, The University of British Columbia, Vancouver, V6T 1Z3, Canada
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Pavón-Fuentes N, Marín-Prida J, Llópiz-Arzuaga A, Falcón-Cama V, Campos-Mojena R, Cervantes-Llanos M, Piniella-Matamoros B, Pentón-Arias E, Pentón-Rol G. Phycocyanobilin reduces brain injury after endothelin-1- induced focal cerebral ischaemia. Clin Exp Pharmacol Physiol 2019; 47:383-392. [PMID: 31732975 DOI: 10.1111/1440-1681.13214] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 09/27/2019] [Accepted: 11/12/2019] [Indexed: 12/11/2022]
Abstract
Pharmacological therapies for interrupting biochemical events of the ischaemic cascade and protecting against stroke in humans are as yet unavailable. Up to now, the neuroprotective activity in cerebral ischaemia of phycocyanobilin (PCB), a tetrapyrrolic natural antioxidant, has not been fully examined. Here, we evaluated if PCB protects PC12 neuronal cells against oxygen and glucose deprivation plus reperfusion, and its protective effects in a rat model of endothelin-1-induced focal brain ischaemia. PCB was purified from the cyanobacteria Spirulina platensis and characterized by spectrophotometric, liquid and gas chromatography and mass spectrometry techniques. In Wistar rats, PCB at 50, 100 and 200 μg/kg or phosphate-buffered saline (vehicle) was administered intraperitoneally at equal subdoses in a therapeutic schedule (30 minutes, 1, 3 and 6 hours after the surgery). Brain expression of myelin basic protein (MBP) and the enzyme CNPase was determined by immunoelectron microscopy. PCB was obtained with high purity (>95%) and the absence of solvent contaminants and was able to ameliorate PC12 cell ischaemic injury. PCB treatment significantly decreased brain infarct volume, limited the exploratory behaviour impairment and preserved viable cortical neurons in ischaemic rats in a dose-dependent manner, compared to the vehicle group. Furthermore, PCB at high doses restored the MBP and CNPase expression levels in ischaemic rats. An improved PCB purification method from its natural source is reported, obtaining PCB that is suitable for pharmacological trials showing neuroprotective effects against experimental ischaemic stroke. Therefore, PCB could be a therapeutic pharmacological alternative for ischaemic stroke patients.
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Affiliation(s)
| | - Javier Marín-Prida
- Centre for Research and Biological Evaluations (CEIEB), Institute of Pharmacy and Food, University of Havana, Havana, Cuba
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Regulation of the heme biosynthetic pathway for combinational biosynthesis of phycocyanobilin in Escherichia coli. Process Biochem 2018. [DOI: 10.1016/j.procbio.2018.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Stiefelmaier J, Ledermann B, Sorg M, Banek A, Geib D, Ulber R, Frankenberg-Dinkel N. Pink bacteria-Production of the pink chromophore phycoerythrobilin with Escherichia coli. J Biotechnol 2018; 274:47-53. [PMID: 29549003 DOI: 10.1016/j.jbiotec.2018.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/01/2018] [Accepted: 03/11/2018] [Indexed: 11/29/2022]
Abstract
Phycoerythrobilin (PEB) is an open-chain tetrapyrrole derived from heme and plays an important role as light-harvesting pigment in the phycobiliproteins of cyanobacteria and red algae. Furthermore, PEB can also function as an antioxidant with potential use as a natural acid stable food colorant. PEB is not commercially available and large, pure quantities can only be obtained by laborious methanolysis of red algae followed by liquid chromatography. Here we describe an improved method for high yield production and purification of PEB in Escherichia coli via heterologous expression where the two required enzymes heme oxygenase and PEB synthase subsequently convert the substrate heme provided by the host cell. Experiments in shaking flasks resulted in the highest product yield of 680.23 ± 42.75 μg PEB per g cell dry weight, by induction with 0.1 mM IPTG. Scale-up to batch-operated fermentation in a 2 L bioreactor reached product concentrations up to 5.02 mg PEB L-1 by adjustment of aeration, induction time, media composition and supplementation of precursors. A further approach included separation of PEB from developed foam above the culture. This enabled continuous product collection during cultivation and simplified product purification. Produced PEB was validated via UV-vis spectroscopy, high pressure liquid chromatography and mass spectrometry.
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Affiliation(s)
- Judith Stiefelmaier
- Lehrgebiet Bioverfahrenstechnik, Technische Universität Kaiserslautern, Gottlieb-Daimler-Straße 49, 67663 Kaiserslautern, Germany.
| | - Benjamin Ledermann
- Abteilung für Mikrobiologie, Technische Universität Kaiserslautern, Erwin-Schroedinger-Straße 56, 67663 Kaiserslautern, Germany.
| | - Michael Sorg
- Lehrgebiet Bioverfahrenstechnik, Technische Universität Kaiserslautern, Gottlieb-Daimler-Straße 49, 67663 Kaiserslautern, Germany.
| | - Angela Banek
- Lehrgebiet Bioverfahrenstechnik, Technische Universität Kaiserslautern, Gottlieb-Daimler-Straße 49, 67663 Kaiserslautern, Germany; Abteilung für Mikrobiologie, Technische Universität Kaiserslautern, Erwin-Schroedinger-Straße 56, 67663 Kaiserslautern, Germany.
| | - Doris Geib
- Lehrgebiet Bioverfahrenstechnik, Technische Universität Kaiserslautern, Gottlieb-Daimler-Straße 49, 67663 Kaiserslautern, Germany.
| | - Roland Ulber
- Lehrgebiet Bioverfahrenstechnik, Technische Universität Kaiserslautern, Gottlieb-Daimler-Straße 49, 67663 Kaiserslautern, Germany.
| | - Nicole Frankenberg-Dinkel
- Abteilung für Mikrobiologie, Technische Universität Kaiserslautern, Erwin-Schroedinger-Straße 56, 67663 Kaiserslautern, Germany.
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Work VH, Melnicki MR, Hill EA, Davies FK, Kucek LA, Beliaev AS, Posewitz MC. Lauric Acid Production in a Glycogen-Less Strain of Synechococcus sp. PCC 7002. Front Bioeng Biotechnol 2015; 3:48. [PMID: 25964950 PMCID: PMC4408914 DOI: 10.3389/fbioe.2015.00048] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Accepted: 03/25/2015] [Indexed: 12/04/2022] Open
Abstract
The cyanobacterium Synechococcus sp. Pasteur culture collection 7002 was genetically engineered to synthesize biofuel-compatible medium-chain fatty acids (FAs) during photoautotrophic growth. Expression of a heterologous lauroyl-acyl carrier protein (C12:0-ACP) thioesterase with concurrent deletion of the endogenous putative acyl-ACP synthetase led to secretion of transesterifiable C12:0 FA in CO2-supplemented batch cultures. When grown at steady state over a range of light intensities in a light-emitting diode turbidostat photobioreactor, the C12-secreting mutant exhibited a modest reduction in growth rate and increased O2 evolution relative to the wild-type (WT). Inhibition of (i) glycogen synthesis by deletion of the glgC-encoded ADP-glucose pyrophosphorylase (AGPase) and (ii) protein synthesis by nitrogen deprivation were investigated as potential mechanisms for metabolite redistribution to increase FA synthesis. Deletion of AGPase led to a 10-fold decrease in reducing carbohydrates and secretion of organic acids during nitrogen deprivation consistent with an energy spilling phenotype. When the carbohydrate-deficient background (ΔglgC) was modified for C12 secretion, no increase in C12 was achieved during nutrient replete growth, and no C12 was recovered from any strain upon nitrogen deprivation under the conditions used. At steady state, the growth rate of the ΔglgC strain saturated at a lower light intensity than the WT, but O2 evolution was not compromised and became increasingly decoupled from growth rate with rising irradiance. Photophysiological properties of the ΔglgC strain suggest energy dissipation from photosystem II and reconfiguration of electron flow at the level of the plastoquinone pool.
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Affiliation(s)
- Victoria H. Work
- Civil and Environmental Engineering Division, Colorado School of Mines, Golden, CO, USA
| | - Matthew R. Melnicki
- Microbiology Group, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Eric A. Hill
- Microbiology Group, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Fiona K. Davies
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO, USA
| | - Leo A. Kucek
- Microbiology Group, Pacific Northwest National Laboratory, Richland, WA, USA
| | | | - Matthew C. Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO, USA
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