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Zhao Z, Liu S, Jiang S, Zhang D, Sha Z. Diversity and Potential Metabolic Characteristics of Culturable Copiotrophic Bacteria That Can Grow on Low-Nutrient Medium in Zhenbei Seamount in the South China Sea. MICROBIAL ECOLOGY 2024; 87:157. [PMID: 39708139 DOI: 10.1007/s00248-024-02475-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 12/04/2024] [Indexed: 12/23/2024]
Abstract
Oligotrophs are predominant in nutrient-poor environments, but copiotrophic bacteria may tolerate conditions of low energy and can also survive and thrive in these nutrient-limited conditions. In the present study, we isolated 648 strains using a dilution plating method after enrichment for low-nutrient conditions. We collected 150 seawater samples at 21 stations in different parts of the water column at the Zhenbei Seamount in the South China Sea. The 648 isolated copiotrophic strains that could grow on low-nutrient medium were in 21 genera and 42 species. A total of 99.4% (644/648) of the bacteria were in the phylum Pseudomonadota, with 73.3% (472/644) in the class Gammaproteobacteria and 26.7% (172/644) in the class Alphaproteobacteria. Among the 42 representative isolates, Pseudoalteromonas arabiensis, Roseibium aggregatum, and Vibrio neocaledonicus were present in all layers of seawater and at almost all of the stations. Almost half of these species (20/42) contained genes that performed nitrate reduction, with confirmation by nitrate reduction testing. These isolates also contained genes that functioned in sulfur metabolism, including sulfate reduction, thiosulfate oxidation, thiosulfate disproportionation, and dimethylsulfoniopropionate degradation. GH23, CBM50, GT4, GT2, and GT51 were the main carbohydrate-active enzymes (CAZymes), and these five enzymes were present in all or almost all of the isolated strains. The most abundant classes of CAZymes were those associated with the degradation of chitin, starch, and cellulose. Collectively, our study of marine copiotrophic bacteria capable of growing on low-nutrient medium demonstrated the diversity of these species and their potential metabolic characteristics.
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Affiliation(s)
- Zhangqi Zhao
- Laboratory of Marine Organism Taxonomy and Phylogeny, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Key Laboratory of Mariculture (Ministry of Education), Fisheries College, Ocean University of China, Qingdao, 266003, China
| | - Sizhen Liu
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Shan Jiang
- Laboratory of Marine Organism Taxonomy and Phylogeny, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Dechao Zhang
- Laboratory of Marine Organism Taxonomy and Phylogeny, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Zhongli Sha
- Laboratory of Marine Organism Taxonomy and Phylogeny, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- Laoshan Laboratory, Qingdao, 266237, China.
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Wang Y, Cui L, Ding L, Su X, Luo H, Huang H, Wang Y, Yao B, Zhang J, Wang X. Unlocking the potential of Cupriavidus necator H16 as a platform for bioproducts production from carbon dioxide. World J Microbiol Biotechnol 2024; 40:389. [PMID: 39572451 DOI: 10.1007/s11274-024-04200-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2024] [Accepted: 11/11/2024] [Indexed: 11/26/2024]
Abstract
The rapid global increase in fossil fuel and energy consumption has resulted in the accumulation of greenhouse gases, especially carbon dioxide (CO2), thus contributing to climate change. Therefore, transforming CO2 into valuable products could yield beneficial outcomes. In this review, the capabilities of Cupriavidus necator H16, a light-independent chemoautotrophic bacterium, as a host platform for the transformation of CO2 into diverse products are explored. We begin by examining the progress in synthetic biology toolkits, gas fermentation technologies, and engineering approaches, considering the chemoautotrophic metabolic traits of C. necator to enhance the capacity of the strain for CO2 fixation. Additionally, recent research focused on the metabolic engineering of C. necator H16 for the conversion of CO2 into biodegradable plastics, biofuels, bioactive compounds, and single-cell proteins was reviewed. Finally, we address the limitations affecting the advancement and utilization of C. necator H16 strain, such as inefficiencies and the range of product types, and offer several recommendations for enhancement. This review acts as a resource for the development of C. necator H16 cell factories and the industrial manufacture of products derived from CO2.
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Affiliation(s)
- Yuheng Wang
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Lin Cui
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Lijuan Ding
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- College of Animal Science, Shanxi Agricultural University, Shanxi, 030600, China
| | - Xiaoyun Su
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Huiying Luo
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Huoqing Huang
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Yuan Wang
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Bin Yao
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Jie Zhang
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
| | - Xiaolu Wang
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
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Long C, Liu Z, Liu R, Yin L, Tan F, Wang Y, He G. Soil microbial CO 2 fixation rate disparities with different vegetation at a representative acidic red soil experimental station in China. Front Microbiol 2024; 15:1480484. [PMID: 39640861 PMCID: PMC11619433 DOI: 10.3389/fmicb.2024.1480484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2024] [Accepted: 10/28/2024] [Indexed: 12/07/2024] Open
Abstract
Soil acidification poses a significant environmental challenge in China's southern red soil regions, impacting the abundance of soil microbes and their capacity for carbon fixation. The effect of vegetation types on soil's biological and abiotic components under acidification, and their regulatory role on the CO2 fixation mechanisms of soil autotrophic microorganisms, is difficult to examine. This gap in understanding constrains the assessment of the carbon fixation potential of red soils. To address this, indoor cultivation coupled with 13C stable isotope labeling was employed to evaluate the disparate abilities of autotrophic microorganisms to assimilate and store CO2 across five vegetation soils from the Qianyanzhou acidic red soil experimental station in China. Findings indicate that carbon fixation rates in these soils spanned from 4.25 to 18.15 mg C kg-1 soil d-1, with paddy field soils demonstrating superior carbon fixation capabilities compared to orchard, coniferous forest, broad-leaved forest, and wasteland soils. The 13C fixation rate in the 0-10 cm soil stratum surpassed that of the 10-30 cm layer across all vegetation types. High-throughput sequencing of 16S rRNA, following cbbL gene purification and amplification, identified Bradyrhizobium, Azospirillum, Burkholderia, Paraburkholderia, and Thermomonospora as the predominant autotrophic carbon-fixing microbial genera in the soil. PERMANOVA analysis attributed 65.72% of the variance in microbial community composition to vegetation type, while soil depth accounted for a mere 8.58%. Network analysis of microbial co-occurrence suggested the soil microbial interactions and network complexity changed with the change of vegetation types. Additionally, multiple linear regression analysis pinpointed the Shannon index and soil organic carbon (SOC) content as primary influencers of carbon fixation rates. Structural equation modeling suggested that iron enrichment and acidification indirectly modulated carbon fixation rates by altering SOC and autotrophic bacterial diversity. This investigation shows the spatial dynamics and mechanisms underpinning microbial carbon fixation across varying vegetation types in southern China's red soil regions.
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Affiliation(s)
- Chao Long
- School of Life Sciences, Key Laboratory of Jiangxi Province for Functional Biology and Pollution Control in Red Soil Regions, Jinggangshan University, Ji’an, Jiangxi, China
- School of Civil and Surveying & Mapping Engineering, Jiangxi University of Science and Technology, Ganzhou, Jiangxi, China
| | - Zuwen Liu
- School of Life Sciences, Key Laboratory of Jiangxi Province for Functional Biology and Pollution Control in Red Soil Regions, Jinggangshan University, Ji’an, Jiangxi, China
- School of Civil and Surveying & Mapping Engineering, Jiangxi University of Science and Technology, Ganzhou, Jiangxi, China
- School of Hydraulic & Ecological Engineering, Nanchang Institute of Technology, Nanchang, Jiangxi, China
| | - Renlu Liu
- School of Life Sciences, Key Laboratory of Jiangxi Province for Functional Biology and Pollution Control in Red Soil Regions, Jinggangshan University, Ji’an, Jiangxi, China
| | - Li Yin
- School of Life Sciences, Key Laboratory of Jiangxi Province for Functional Biology and Pollution Control in Red Soil Regions, Jinggangshan University, Ji’an, Jiangxi, China
| | - Fuxing Tan
- School of Life Sciences, Key Laboratory of Jiangxi Province for Functional Biology and Pollution Control in Red Soil Regions, Jinggangshan University, Ji’an, Jiangxi, China
| | - Yian Wang
- School of Life Sciences, Key Laboratory of Jiangxi Province for Functional Biology and Pollution Control in Red Soil Regions, Jinggangshan University, Ji’an, Jiangxi, China
| | - Genhe He
- School of Life Sciences, Key Laboratory of Jiangxi Province for Functional Biology and Pollution Control in Red Soil Regions, Jinggangshan University, Ji’an, Jiangxi, China
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Dukat AM, Elcheninov AG, Klyukina AA, Novikov AA, Frolov EN. Thiobacter aerophilum sp. nov., a Thermophilic, Obligately Chemolithoautotrophic, Sulfur-Oxidizing Bacterium from a Hot Spring and Proposal of Thiobacteraceae fam. nov. Microorganisms 2024; 12:2252. [PMID: 39597641 PMCID: PMC11596669 DOI: 10.3390/microorganisms12112252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2024] [Revised: 11/02/2024] [Accepted: 11/05/2024] [Indexed: 11/29/2024] Open
Abstract
An aerobic, obligately chemolithoautotrophic, sulfur-oxidizing bacterium, strain AK1T, was isolated from a terrestrial hot spring of the Uzon Caldera, Kamchatka, Russia. The cells of the new isolate were Gram-negative motile rods with a single polar flagellum. Strain AK1T grew at 37-55 °C (optimum 50 °C) with 0-1.0% NaCl (optimum 0%) and within the pH range 4.8-7.0 (optimum pH 5.2-5.5). The new isolate was able to grow by aerobic respiration with sulfide, sulfur, or thiosulfate as the electron donor and HCO3-/CO2 as the carbon source. The major fatty acids were C16:0, C17:1 Δ, and C16:1 ω7c. The respiratory lipoquinone was ubiquinone UQ-8. The size of the genome and genomic DNA G+C content of the strain AK1T were 2.55 Mb and 64.0%, respectively. The closest 16S rRNA gene sequence of a validly published species belonged to Thiobacter subterraneus C55T (97.94% identity). According to the 16S rRNA gene sequence-based and conserved protein sequences-based phylogenetic analyses, strain AK1T represented a distinct lineage of the genus Thiobacter within a new family, Thiobacteraceae of the order Burkholderiales. As inferred from the morphology, physiology, chemotaxonomy, and phylogeny, strain AK1T ought to be recognized as a novel species for which we propose the name Thiobacter aerophilum sp. nov. The type strain is AK1T (=CGMCC 1.18099T = UQM 41819T).
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Affiliation(s)
- Anna M. Dukat
- Winogradsky Institute of Microbiology, Federal Research Center of Biotechnology, Russian Academy of Sciences, 60 Let Oktjabrja Pr-t, 7, Bld. 2, 117312 Moscow, Russia; (A.M.D.); (A.G.E.); (E.N.F.)
| | - Alexander G. Elcheninov
- Winogradsky Institute of Microbiology, Federal Research Center of Biotechnology, Russian Academy of Sciences, 60 Let Oktjabrja Pr-t, 7, Bld. 2, 117312 Moscow, Russia; (A.M.D.); (A.G.E.); (E.N.F.)
| | - Alexandra A. Klyukina
- Winogradsky Institute of Microbiology, Federal Research Center of Biotechnology, Russian Academy of Sciences, 60 Let Oktjabrja Pr-t, 7, Bld. 2, 117312 Moscow, Russia; (A.M.D.); (A.G.E.); (E.N.F.)
| | - Andrei A. Novikov
- Department of Physical and Colloid Chemistry, Gubkin University, Leninskiy Prospect, 65/1, 119991 Moscow, Russia;
| | - Evgenii N. Frolov
- Winogradsky Institute of Microbiology, Federal Research Center of Biotechnology, Russian Academy of Sciences, 60 Let Oktjabrja Pr-t, 7, Bld. 2, 117312 Moscow, Russia; (A.M.D.); (A.G.E.); (E.N.F.)
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Ranaivoarisoa TO, Bai W, Karthikeyan R, Steele H, Silberman M, Olabode J, Conners E, Gallagher B, Bose A. Overexpression of RuBisCO form I and II genes in Rhodopseudomonas palustris TIE-1 augments polyhydroxyalkanoate production heterotrophically and autotrophically. Appl Environ Microbiol 2024; 90:e0143824. [PMID: 39162566 PMCID: PMC11409669 DOI: 10.1128/aem.01438-24] [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: 07/18/2024] [Accepted: 07/30/2024] [Indexed: 08/21/2024] Open
Abstract
With the rising demand for sustainable renewable resources, microorganisms capable of producing bioproducts such as bioplastics are attractive. While many bioproduction systems are well-studied in model organisms, investigating non-model organisms is essential to expand the field and utilize metabolically versatile strains. This investigation centers on Rhodopseudomonas palustris TIE-1, a purple non-sulfur bacterium capable of producing bioplastics. To increase bioplastic production, genes encoding the putative regulatory protein PhaR and the depolymerase PhaZ of the polyhydroxyalkanoate (PHA) biosynthesis pathway were deleted. Genes associated with pathways that might compete with PHA production, specifically those linked to glycogen production and nitrogen fixation, were deleted. Additionally, RuBisCO form I and II genes were integrated into TIE-1's genome by a phage integration system, developed in this study. Our results show that deletion of phaR increases PHA production when TIE-1 is grown photoheterotrophically with butyrate and ammonium chloride (NH4Cl). Mutants unable to produce glycogen or fix nitrogen show increased PHA production under photoautotrophic growth with hydrogen and NH4Cl. The most significant increase in PHA production was observed when RuBisCO form I and form I & II genes were overexpressed, five times under photoheterotrophy with butyrate, two times with hydrogen and NH4Cl, and two times under photoelectrotrophic growth with N2 . In summary, inserting copies of RuBisCO genes into the TIE-1 genome is a more effective strategy than deleting competing pathways to increase PHA production in TIE-1. The successful use of the phage integration system opens numerous opportunities for synthetic biology in TIE-1.IMPORTANCEOur planet has been burdened by pollution resulting from the extensive use of petroleum-derived plastics for the last few decades. Since the discovery of biodegradable plastic alternatives, concerted efforts have been made to enhance their bioproduction. The versatile microorganism Rhodopseudomonas palustris TIE-1 (TIE-1) stands out as a promising candidate for bioplastic synthesis, owing to its ability to use multiple electron sources, fix the greenhouse gas CO2, and use light as an energy source. Two categories of strains were meticulously designed from the TIE-1 wild-type to augment the production of polyhydroxyalkanoate (PHA), one such bioplastic produced. The first group includes mutants carrying a deletion of the phaR or phaZ genes in the PHA pathway, and those lacking potential competitive carbon and energy sinks to the PHA pathway (namely, glycogen biosynthesis and nitrogen fixation). The second group comprises TIE-1 strains that overexpress RuBisCO form I or form I & II genes inserted via a phage integration system. By studying numerous metabolic mutants and overexpression strains, we conclude that genetic modifications in the environmental microbe TIE-1 can improve PHA production. When combined with other approaches (such as reactor design, use of microbial consortia, and different feedstocks), genetic and metabolic manipulations of purple nonsulfur bacteria like TIE-1 are essential for replacing petroleum-derived plastics with biodegradable plastics like PHA.
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Affiliation(s)
| | - Wei Bai
- LifeFoundry, San Jose, California, USA
| | | | - Hope Steele
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Miriam Silberman
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Jennifer Olabode
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Eric Conners
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Brian Gallagher
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Arpita Bose
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
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Cai T, Gao X, Qi X, Wang X, Liu R, Zhang L, Wang X. Role of the cathode chamber in microbial electrosynthesis: A comprehensive review of key factors. ENGINEERING MICROBIOLOGY 2024; 4:100141. [PMID: 39629110 PMCID: PMC11611015 DOI: 10.1016/j.engmic.2024.100141] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 02/14/2024] [Accepted: 02/16/2024] [Indexed: 12/06/2024]
Abstract
The consumption of non-renewable fossil fuels has directly contributed to a dramatic rise in global carbon dioxide (CO2) emissions, posing an ongoing threat to the ecological security of the Earth. Microbial electrosynthesis (MES) is an innovative energy regeneration strategy that offers a gentle and efficient approach to converting CO2 into high-value products. The cathode chamber is a vital component of an MES system and its internal factors play crucial roles in improving the performance of the MES system. Therefore, this review aimed to provide a detailed analysis of the key factors related to the cathode chamber in the MES system. The topics covered include inward extracellular electron transfer pathways, cathode materials, applied cathode potentials, catholyte pH, and reactor configuration. In addition, this review analyzes and discusses the challenges and promising avenues for improving the conversion of CO2 into high-value products via MES.
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Affiliation(s)
- Ting Cai
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Xinyu Gao
- College of Arts & Science, University of North Carolina at Chapel Hill, Chapel Hill 27514, NC, United States
| | - Xiaoyan Qi
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Xiaolei Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Ruijun Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Lei Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Xia Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
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Santolin L, Riedel SL, Brigham CJ. Synthetic biology toolkit of Ralstonia eutropha (Cupriavidus necator). Appl Microbiol Biotechnol 2024; 108:450. [PMID: 39207499 PMCID: PMC11362209 DOI: 10.1007/s00253-024-13284-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 08/09/2024] [Accepted: 08/12/2024] [Indexed: 09/04/2024]
Abstract
Synthetic biology encompasses many kinds of ideas and techniques with the common theme of creating something novel. The industrially relevant microorganism, Ralstonia eutropha (also known as Cupriavidus necator), has long been a subject of metabolic engineering efforts to either enhance a product it naturally makes (polyhydroxyalkanoate) or produce novel bioproducts (e.g., biofuels and other small molecule compounds). Given the metabolic versatility of R. eutropha and the existence of multiple molecular genetic tools and techniques for the organism, development of a synthetic biology toolkit is underway. This toolkit will allow for novel, user-friendly design that can impart new capabilities to R. eutropha strains to be used for novel application. This article reviews the different synthetic biology techniques currently available for modifying and enhancing bioproduction in R. eutropha. KEY POINTS: • R. eutropha (C. necator) is a versatile organism that has been examined for many applications. • Synthetic biology is being used to design more powerful strains for bioproduction. • A diverse synthetic biology toolkit is being developed to enhance R. eutropha's capabilities.
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Affiliation(s)
- Lara Santolin
- Technische Universität Berlin, Institute of Biotechnology, Chair of Bioprocess Engineering, Berlin, Germany
| | - Sebastian L Riedel
- Berliner Hochschule Für Technik, Department VIII - Mechanical Engineering, Event Technology and Process Engineering, Environmental and Bioprocess Engineering Laboratory, Berlin, Germany.
| | - Christopher J Brigham
- Department of Bioengineering, University of Massachusetts Dartmouth, North Dartmouth, MA, USA.
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Wang CT, Sivashankari RM, Miyahara Y, Tsuge T. Polyhydroxyalkanoate Copolymer Production by Recombinant Ralstonia eutropha Strain 1F2 from Fructose or Carbon Dioxide as Sole Carbon Source. Bioengineering (Basel) 2024; 11:455. [PMID: 38790321 PMCID: PMC11117859 DOI: 10.3390/bioengineering11050455] [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: 03/30/2024] [Revised: 04/23/2024] [Accepted: 04/29/2024] [Indexed: 05/26/2024] Open
Abstract
Ralstonia eutropha strain H16 is a chemoautotrophic bacterium that oxidizes hydrogen and accumulates poly[(R)-3-hydroxybutyrate] [P(3HB)], a prominent polyhydroxyalkanoate (PHA), within its cell. R. eutropha utilizes fructose or CO2 as its sole carbon source for this process. A PHA-negative mutant of strain H16, known as R. eutropha strain PHB-4, cannot produce PHA. Strain 1F2, derived from strain PHB-4, is a leucine analog-resistant mutant. Remarkably, the recombinant 1F2 strain exhibits the capacity to synthesize 3HB-based PHA copolymers containing 3-hydroxyvalerate (3HV) and 3-hydroxy-4-methyvalerate (3H4MV) comonomer units from fructose or CO2. This ability is conferred by the expression of a broad substrate-specific PHA synthase and tolerance to feedback inhibition of branched amino acids. However, the total amount of comonomer units incorporated into PHA was up to around 5 mol%. In this study, strain 1F2 underwent genetic engineering to augment the comonomer supply incorporated into PHA. This enhancement involved several modifications, including the additional expression of the broad substrate-specific 3-ketothiolase gene (bktB), the heterologous expression of the 2-ketoacid decarboxylase gene (kivd), and the phenylacetaldehyde dehydrogenase gene (padA). Furthermore, the genome of strain 1F2 was altered through the deletion of the 3-hydroxyacyl-CoA dehydrogenase gene (hbdH). The introduction of bktB-kivd-padA resulted in increased 3HV incorporation, reaching 13.9 mol% from fructose and 6.4 mol% from CO2. Additionally, the hbdH deletion resulted in the production of PHA copolymers containing (S)-3-hydroxy-2-methylpropionate (3H2MP). Interestingly, hbdH deletion increased the weight-average molecular weight of the PHA to over 3.0 × 106 on fructose. Thus, it demonstrates the positive effects of hbdH deletion on the copolymer composition and molecular weight of PHA.
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Affiliation(s)
| | | | - Yuki Miyahara
- Department of Materials Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan
| | - Takeharu Tsuge
- Department of Materials Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan
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Wang L, Yao J, Tu T, Yao B, Zhang J. Heterotrophic and autotrophic production of L-isoleucine and L-valine by engineered Cupriavidus necator H16. BIORESOURCE TECHNOLOGY 2024; 398:130538. [PMID: 38452952 DOI: 10.1016/j.biortech.2024.130538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 02/14/2024] [Accepted: 03/04/2024] [Indexed: 03/09/2024]
Abstract
Advancement in commodity chemical production from carbon dioxide (CO2) offers a promising path towards sustainable development goal. Cupriavidus necator is an ideal host to convert CO2 into high-value chemicals, thereby achieving this target. Here, C. necator was engineered for heterotrophic and autotrophic production of L-isoleucine and L-valine. Citramalate synthase was introduced to simplify isoleucine synthesis pathway. Blocking poly-hydroxybutyrate biosynthesis resulted in significant accumulation of isoleucine and valine. Besides, strategies like key enzymes screening and overexpressing, reducing power balancing and feedback inhibition removing were applied in strain modification. Finally, the maximum isoleucine and valine titers of the best isoleucine-producing and valine-producing strains reached 857 and 972 mg/L, respectively, in fed-batch fermentation using glucose as substrate, and 105 and 319 mg/L, respectively, in autotrophic fermentation using CO2 as substrate. This study provides a feasible solution for developing C. necator as a microbial factory to produce amino acids from CO2.
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Affiliation(s)
- Lei Wang
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China; College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Junhu Yao
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Tao Tu
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Bin Yao
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China; College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jie Zhang
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
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Hudson EP. The Calvin Benson cycle in bacteria: New insights from systems biology. Semin Cell Dev Biol 2024; 155:71-83. [PMID: 37002131 DOI: 10.1016/j.semcdb.2023.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 02/21/2023] [Accepted: 03/16/2023] [Indexed: 03/31/2023]
Abstract
The Calvin Benson cycle in phototrophic and chemolithoautotrophic bacteria has ecological and biotechnological importance, which has motivated study of its regulation. I review recent advances in our understanding of how the Calvin Benson cycle is regulated in bacteria and the technologies used to elucidate regulation and modify it, and highlight differences between and photoautotrophic and chemolithoautotrophic models. Systems biology studies have shown that in oxygenic phototrophic bacteria, Calvin Benson cycle enzymes are extensively regulated at post-transcriptional and post-translational levels, with multiple enzyme activities connected to cellular redox status through thioredoxin. In chemolithoautotrophic bacteria, regulation is primarily at the transcriptional level, with effector metabolites transducing cell status, though new methods should now allow facile, proteome-wide exploration of biochemical regulation in these models. A biotechnological objective is to enhance CO2 fixation in the cycle and partition that carbon to a product of interest. Flux control of CO2 fixation is distributed over multiple enzymes, and attempts to modulate gene Calvin cycle gene expression show a robust homeostatic regulation of growth rate, though the synthesis rates of products can be significantly increased. Therefore, de-regulation of cycle enzymes through protein engineering may be necessary to increase fluxes. Non-canonical Calvin Benson cycles, if implemented with synthetic biology, could have reduced energy demand and enzyme loading, thus increasing the attractiveness of these bacteria for industrial applications.
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Affiliation(s)
- Elton P Hudson
- Department of Protein Science, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden.
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11
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Zhao L, Cai Z, Li Y, Zhang Y. Engineering Rubisco to enhance CO 2 utilization. Synth Syst Biotechnol 2024; 9:55-68. [PMID: 38273863 PMCID: PMC10809010 DOI: 10.1016/j.synbio.2023.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 12/15/2023] [Accepted: 12/25/2023] [Indexed: 01/27/2024] Open
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is a pivotal enzyme that mediates the fixation of CO2. As the most abundant protein on earth, Rubisco has a significant impact on global carbon, water, and nitrogen cycles. However, the significantly low carboxylation activity and competing oxygenase activity of Rubisco greatly impede high carbon fixation efficiency. This review first summarizes the current efforts in directly or indirectly modifying plant Rubisco, which has been challenging due to its high conservation and limitations in chloroplast transformation techniques. However, recent advancements in understanding Rubisco biogenesis with the assistance of chaperones have enabled successful heterologous expression of all Rubisco forms, including plant Rubisco, in microorganisms. This breakthrough facilitates the acquisition and evaluation of modified proteins, streamlining the measurement of their activity. Moreover, the establishment of a screening system in E. coli opens up possibilities for obtaining high-performance mutant enzymes through directed evolution. Finally, this review emphasizes the utilization of Rubisco in microorganisms, not only expanding their carbon-fixing capabilities but also holding significant potential for enhancing biotransformation processes.
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Affiliation(s)
- Lei Zhao
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhen Cai
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yin Li
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yanping Zhang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
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12
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Diankristanti PA, Lin YC, Yi YC, Ng IS. Polyhydroxyalkanoates bioproduction from bench to industry: Thirty years of development towards sustainability. BIORESOURCE TECHNOLOGY 2024; 393:130149. [PMID: 38049017 DOI: 10.1016/j.biortech.2023.130149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 12/06/2023]
Abstract
The pursuit of carbon neutrality goals has sparked considerable interest in expanding bioplastics production from microbial cell factories. One prominent class of bioplastics, polyhydroxyalkanoates (PHA), is generated by specific microorganisms, serving as carbon and energy storage materials. To begin with, a native PHA producer, Cupriavidus necator (formerly Ralstonia eutropha) is extensively studied, covering essential topics such as carbon source selection, cultivation techniques, and accumulation enhancement strategies. Recently, various hosts including archaea, bacteria, cyanobacteria, yeast, and plants have been explored, stretching the limit of microbial PHA production. This review provides a comprehensive overview of current advancements in PHA bioproduction, spanning from the native to diversified cell factories. Recovery and purification techniques are discussed, and the current status of industrial applications is assessed as a critical milestone for startups. Ultimately, it concludes by addressing contemporary challenges and future prospects, offering insights into the path towards reduced carbon emissions and sustainable development goals.
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Affiliation(s)
| | - Yu-Chieh Lin
- Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Ying-Chen Yi
- Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan; Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, USA
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan.
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13
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Arhar S, Rauter T, Stolterfoht-Stock H, Lambauer V, Kratzer R, Winkler M, Karava M, Kourist R, Emmerstorfer-Augustin A. CO 2-based production of phytase from highly stable expression plasmids in Cupriavidus necator H16. Microb Cell Fact 2024; 23:9. [PMID: 38172920 PMCID: PMC10763379 DOI: 10.1186/s12934-023-02280-2] [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: 11/03/2023] [Accepted: 12/18/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND Existing plasmid systems offer a fundamental foundation for gene expression in Cupriavidus necator; however, their applicability is constrained by the limitations of conjugation. Low segregational stabilities and plasmid copy numbers, particularly in the absence of selection pressure, pose challenges. Phytases, recognized for their widespread application as supplements in animal feed to enhance phosphate availability, present an intriguing prospect for heterologous production in C. necator. The establishment of stable, high-copy number plasmid that can be electroporated would support the utilization of C. necator for the production of single-cell protein from CO2. RESULTS In this study, we introduce a novel class of expression plasmids specifically designed for electroporation. These plasmids contain partitioning systems to boost segregation stability, eliminating the need for selection pressure. As a proof of concept, we successfully produced Escherichia coli derived AppA phytase in C. necator H16 PHB- 4 using these improved plasmids. Expression was directed by seven distinct promoters, encompassing the constitutive j5 promoter, hydrogenase promoters, and those governing the Calvin-Benson-Bassham cycle. The phytase activities observed in recombinant C. necator H16 strains ranged from 2 to 50 U/mg of total protein, contingent upon the choice of promoter and the mode of cell cultivation - heterotrophic or autotrophic. Further, an upscaling experiment conducted in a 1 l fed-batch gas fermentation system resulted in the attainment of the theoretical biomass. Phytase activity reached levels of up to 22 U/ml. CONCLUSION The new expression system presented in this study offers a highly efficient platform for protein production and a wide array of synthetic biology applications. It incorporates robust promoters that exhibit either constitutive activity or can be selectively activated when cells transition from heterotrophic to autotrophic growth. This versatility makes it a powerful tool for tailored gene expression. Moreover, the potential to generate active phytases within C. necator H16 holds promising implications for the valorization of CO2 in the feed industry.
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Affiliation(s)
- Simon Arhar
- Austrian Centre of Industrial Biotechnology, acib GmbH, Krenngasse 37, Graz, 8010, Austria
| | - Thomas Rauter
- Austrian Centre of Industrial Biotechnology, acib GmbH, Krenngasse 37, Graz, 8010, Austria
| | | | - Vera Lambauer
- Austrian Centre of Industrial Biotechnology, acib GmbH, Krenngasse 37, Graz, 8010, Austria
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Petersgasse 12, Graz, 8010, Austria
| | - Regina Kratzer
- Austrian Centre of Industrial Biotechnology, acib GmbH, Krenngasse 37, Graz, 8010, Austria
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Petersgasse 12, Graz, 8010, Austria
| | - Margit Winkler
- Austrian Centre of Industrial Biotechnology, acib GmbH, Krenngasse 37, Graz, 8010, Austria
- Institute of Molecular Biotechnology, Graz University of Technology, NAWI Graz, Petersgasse 14, Graz, 8010, Austria
| | - Marianna Karava
- Institute of Molecular Biotechnology, Graz University of Technology, NAWI Graz, Petersgasse 14, Graz, 8010, Austria
| | - Robert Kourist
- Austrian Centre of Industrial Biotechnology, acib GmbH, Krenngasse 37, Graz, 8010, Austria
- Institute of Molecular Biotechnology, Graz University of Technology, NAWI Graz, Petersgasse 14, Graz, 8010, Austria
| | - Anita Emmerstorfer-Augustin
- Austrian Centre of Industrial Biotechnology, acib GmbH, Krenngasse 37, Graz, 8010, Austria.
- Institute of Molecular Biotechnology, Graz University of Technology, NAWI Graz, Petersgasse 14, Graz, 8010, Austria.
- BioTechMed-Graz, Graz, Austria.
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14
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Ma R, Li J, Tyagi RD, Zhang X. Carbon dioxide and methane as carbon source for the production of polyhydroxyalkanoates and concomitant carbon fixation. BIORESOURCE TECHNOLOGY 2024; 391:129977. [PMID: 37925086 DOI: 10.1016/j.biortech.2023.129977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/01/2023] [Accepted: 11/01/2023] [Indexed: 11/06/2023]
Abstract
The currently used plastics are non-biodegradable, and cause greenhouse gases (GHGs) emission as they are petroleum-based. Polyhydroxyalkanoates (PHAs) are biopolymers with excellent biodegradability and biocompatibility, which can be used to replace petroleum-based plastics. A variety of microorganisms have been found to synthesize PHAs by using typical GHGs: carbon dioxide and methane as carbon sources. Converting carbon dioxide (CO2) and methane (CH4) to PHAs is an attractive option for carbon capture and biodegradable plastic production. In this review, the microorganisms capable of using CO2 and CH4 to produce PHAs were summarized. The metabolic mechanism, PHAs production process, and the factors influencing the production process are illustrated. The currently used optimization techniques to improve the yield of PHAs are discussed. The challenges and future prospects for developing economically viable PHAs production using GHGs as carbon source are identified. This work provides an insight for achieving carbon sequestration and bioplastics based circular economy.
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Affiliation(s)
- Rui Ma
- School of Civil and Environmental Engineering, Shenzhen Key Laboratory of Water Resource Application and Environmental Pollution Control, Harbin Institute of Technology, Shenzhen, Shenzhen Guangdong 518055, PR China
| | - Ji Li
- School of Civil and Environmental Engineering, Shenzhen Key Laboratory of Water Resource Application and Environmental Pollution Control, Harbin Institute of Technology, Shenzhen, Shenzhen Guangdong 518055, PR China
| | - R D Tyagi
- Chief Scientific Officer, BOSK-Bioproducts, Quebec, Canada
| | - Xiaolei Zhang
- School of Civil and Environmental Engineering, Shenzhen Key Laboratory of Water Resource Application and Environmental Pollution Control, Harbin Institute of Technology, Shenzhen, Shenzhen Guangdong 518055, PR China.
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15
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Kurt E, Qin J, Williams A, Zhao Y, Xie D. Perspectives for Using CO 2 as a Feedstock for Biomanufacturing of Fuels and Chemicals. Bioengineering (Basel) 2023; 10:1357. [PMID: 38135948 PMCID: PMC10740661 DOI: 10.3390/bioengineering10121357] [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: 10/17/2023] [Revised: 11/20/2023] [Accepted: 11/24/2023] [Indexed: 12/24/2023] Open
Abstract
Microbial cell factories offer an eco-friendly alternative for transforming raw materials into commercially valuable products because of their reduced carbon impact compared to conventional industrial procedures. These systems often depend on lignocellulosic feedstocks, mainly pentose and hexose sugars. One major hurdle when utilizing these sugars, especially glucose, is balancing carbon allocation to satisfy energy, cofactor, and other essential component needs for cellular proliferation while maintaining a robust yield. Nearly half or more of this carbon is inevitably lost as CO2 during the biosynthesis of regular metabolic necessities. This loss lowers the production yield and compromises the benefit of reducing greenhouse gas emissions-a fundamental advantage of biomanufacturing. This review paper posits the perspectives of using CO2 from the atmosphere, industrial wastes, or the exhausted gases generated in microbial fermentation as a feedstock for biomanufacturing. Achieving the carbon-neutral or -negative goals is addressed under two main strategies. The one-step strategy uses novel metabolic pathway design and engineering approaches to directly fix the CO2 toward the synthesis of the desired products. Due to the limitation of the yield and efficiency in one-step fixation, the two-step strategy aims to integrate firstly the electrochemical conversion of the exhausted CO2 into C1/C2 products such as formate, methanol, acetate, and ethanol, and a second fermentation process to utilize the CO2-derived C1/C2 chemicals or co-utilize C5/C6 sugars and C1/C2 chemicals for product formation. The potential and challenges of using CO2 as a feedstock for future biomanufacturing of fuels and chemicals are also discussed.
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Affiliation(s)
- Elif Kurt
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
| | - Jiansong Qin
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
| | - Alexandria Williams
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
| | - Youbo Zhao
- Physical Sciences Inc., 20 New England Business Ctr., Andover, MA 01810, USA;
| | - Dongming Xie
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
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16
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Tang R, Yuan X, Yang J. Problems and corresponding strategies for converting CO 2 into value-added products in Cupriavidus necator H16 cell factories. Biotechnol Adv 2023; 67:108183. [PMID: 37286176 DOI: 10.1016/j.biotechadv.2023.108183] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/17/2023] [Accepted: 05/31/2023] [Indexed: 06/09/2023]
Abstract
Elevated CO2 emissions have substantially altered the worldwide climate, while the excessive reliance on fossil fuels has exacerbated the energy crisis. Therefore, the conversion of CO2 into fuel, petroleum-based derivatives, drug precursors, and other value-added products is expected. Cupriavidus necator H16 is the model organism of the "Knallgas" bacterium and is considered to be a microbial cell factory as it can convert CO2 into various value-added products. However, the development and application of C. necator H16 cell factories has several limitations, including low efficiency, high cost, and safety concerns arising from the autotrophic metabolic characteristics of the strains. In this review, we first considered the autotrophic metabolic characteristics of C. necator H16, and then categorized and summarized the resulting problems. We also provided a detailed discussion of some corresponding strategies concerning metabolic engineering, trophic models, and cultivation mode. Finally, we provided several suggestions for improving and combining them. This review might help in the research and application of the conversion of CO2 into value-added products in C. necator H16 cell factories.
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Affiliation(s)
- Ruohao Tang
- Energy-rich Compounds Production by Photosynthetic Carbon Fixation Research Center, Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, Qingdao, 266109, Shandong Province, People's Republic of China; Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, Shandong Province, People's Republic of China
| | - Xianzheng Yuan
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, Shandong Province, People's Republic of China
| | - Jianming Yang
- Energy-rich Compounds Production by Photosynthetic Carbon Fixation Research Center, Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, Qingdao, 266109, Shandong Province, People's Republic of China.
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17
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Collas F, Dronsella BB, Kubis A, Schann K, Binder S, Arto N, Claassens NJ, Kensy F, Orsi E. Engineering the biological conversion of formate into crotonate in Cupriavidus necator. Metab Eng 2023; 79:49-65. [PMID: 37414134 DOI: 10.1016/j.ymben.2023.06.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 06/08/2023] [Accepted: 06/29/2023] [Indexed: 07/08/2023]
Abstract
To advance the sustainability of the biobased economy, our society needs to develop novel bioprocesses based on truly renewable resources. The C1-molecule formate is increasingly proposed as carbon and energy source for microbial fermentations, as it can be efficiently generated electrochemically from CO2 and renewable energy. Yet, its biotechnological conversion into value-added compounds has been limited to a handful of examples. In this work, we engineered the natural formatotrophic bacterium C. necator as cell factory to enable biological conversion of formate into crotonate, a platform short-chain unsaturated carboxylic acid of biotechnological relevance. First, we developed a small-scale (150-mL working volume) cultivation setup for growing C. necator in minimal medium using formate as only carbon and energy source. By using a fed-batch strategy with automatic feeding of formic acid, we could increase final biomass concentrations 15-fold compared to batch cultivations in flasks. Then, we engineered a heterologous crotonate pathway in the bacterium via a modular approach, where each pathway section was assessed using multiple candidates. The best performing modules included a malonyl-CoA bypass for increasing the thermodynamic drive towards the intermediate acetoacetyl-CoA and subsequent conversion to crotonyl-CoA through partial reverse β-oxidation. This pathway architecture was then tested for formate-based biosynthesis in our fed-batch setup, resulting in a two-fold higher titer, three-fold higher productivity, and five-fold higher yield compared to the strain not harboring the bypass. Eventually, we reached a maximum product titer of 148.0 ± 6.8 mg/L. Altogether, this work consists in a proof-of-principle integrating bioprocess and metabolic engineering approaches for the biological upgrading of formate into a value-added platform chemical.
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Affiliation(s)
| | - Beau B Dronsella
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | | | - Karin Schann
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | | | | | - Nico J Claassens
- Laboratory of Microbiology, Wageningen University, Wageningen, the Netherlands
| | | | - Enrico Orsi
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany.
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18
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Wang X, Chang F, Wang T, Luo H, Su X, Tu T, Wang Y, Bai Y, Qin X, Zhang H, Wang Y, Yao B, Huang H, Zhang J. Production of N-acetylglucosamine from carbon dioxide by engineering Cupriavidus necator H16. BIORESOURCE TECHNOLOGY 2023; 379:129024. [PMID: 37028529 DOI: 10.1016/j.biortech.2023.129024] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 04/01/2023] [Accepted: 04/03/2023] [Indexed: 05/03/2023]
Abstract
The conversion of CO2 into valuable bioactive substances using synthetic biological techniques is a potential approach for mitigating the greenhouse effect. Here, the engineering of C. necator H16 to produce N-acetylglucosamine (GlcNAc) from CO2 is reported. First, GlcNAc importation and intracellular metabolic pathways were disrupted by the deletion of nagF, nagE, nagC, nagA and nagB genes. Second, the GlcNAc-6-phosphate N-acetyltransferase gene (gna1) was screened. A GlcNAc-producing strain was constructed by overexpressing a mutant gna1 from Caenorhabditis elegans. A further increase in GlcNAc production was achieved by disrupting poly(3-hydroxybutyrate) biosynthesis and the Entner-Doudoroff pathways. The maximum GlcNAc titers were 199.9 and 566.3 mg/L for fructose and glycerol, respectively. Finally, the best strain achieved a GlcNAc titer of 75.3 mg/L in autotrophic fermentation. This study demonstrated a conversion of CO2 to GlcNAc, thereby providing a feasible approach for the biosynthesis of various bioactive chemicals from CO2 under normal conditions..
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Affiliation(s)
- Xiaolu Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Fangfang Chang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Tingting Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Huiying Luo
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiaoyun Su
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Tao Tu
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yuan Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yingguo Bai
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xing Qin
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Honglian Zhang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yaru Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Bin Yao
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Huoqing Huang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Jie Zhang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
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19
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Chen K, Ma C, Cheng X, Wang Y, Guo K, Wu R, Zhu Z. Construction of Cupriavidus necator displayed with superoxide dismutases for enhanced growth in bioelectrochemical systems. BIORESOUR BIOPROCESS 2023; 10:36. [PMID: 38647886 PMCID: PMC10992759 DOI: 10.1186/s40643-023-00655-2] [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: 03/03/2023] [Accepted: 05/28/2023] [Indexed: 04/25/2024] Open
Abstract
It is of great significance to utilize CO2 as feedstock to synthesize biobased products, particularly single cell protein (SCP) as the alternative food and feed. Bioelectrochemical system (BES) driven by clean electric energy has been regarded as a promising way for Cupriavidus necator to produce SCP from CO2 directly. At present, the key problem of culturing C. necator in BES is that reactive oxygen species (ROS) generated in cathode chamber are harmful to bacterial growth. Therefore, it is necessary to find a solution to mitigate the negative effect of ROS. In this study, we constructed a number of C. necator strains displayed with superoxide dismutase (SOD), which allowed the decomposition of superoxide anion radical. The effects of promoters and signal peptides on the cell surface displayed SOD were analyzed. The proteins displayed on the surface were further verified by the fluorescence experiment. Finally, the growth of C. necator CMS incorporating a pBAD-SOD-E-tag-IgAβ plasmid could achieve 4.9 ± 1.0 of OD600 by 7 days, equivalent to 1.7 ± 0.3 g/L dry cell weight (DCW), and the production rate was 0.24 ± 0.04 g/L/d DCW, around 2.7-fold increase than the original C. necator CMS (1.8 ± 0.3 of OD600). This study can provide an effective and novel strategy of cultivating strains for the production of CO2-derived SCP or other chemicals in BES.
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Affiliation(s)
- Ke Chen
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, China
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 Xiqidao, Tianjin Airport Economic Park, Tianjin, 300308, China
| | - Chunling Ma
- Haihe Laboratory of Synthetic Biology, 21 Xishiwudao, Tianjin Airport Economic Park, Tianjin, 300308, China
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 Xiqidao, Tianjin Airport Economic Park, Tianjin, 300308, China
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Xiaolei Cheng
- University of Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing, 100049, China
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 Xiqidao, Tianjin Airport Economic Park, Tianjin, 300308, China
| | - Yuhua Wang
- University of Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing, 100049, China
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 Xiqidao, Tianjin Airport Economic Park, Tianjin, 300308, China
| | - Kun Guo
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Ranran Wu
- University of Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing, 100049, China
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 Xiqidao, Tianjin Airport Economic Park, Tianjin, 300308, China
| | - Zhiguang Zhu
- University of Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing, 100049, China.
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 Xiqidao, Tianjin Airport Economic Park, Tianjin, 300308, China.
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20
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Wei H, Wang W, Chou YC, Himmel ME, Chen X, Bomble YJ, Zhang M. Prospects for engineering Ralstonia eutropha and Zymomonas mobilis for the autotrophic production of 2,3-butanediol from CO 2 and H 2. ENGINEERING MICROBIOLOGY 2023; 3:100074. [PMID: 39629244 PMCID: PMC11610990 DOI: 10.1016/j.engmic.2023.100074] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 01/02/2023] [Accepted: 01/06/2023] [Indexed: 12/07/2024]
Abstract
The decarbonization of the chemical industry and a shift toward circular economies because of high global CO2 emissions make CO2 an attractive feedstock for manufacturing chemicals. Moreover, H2 is a low-cost and carbon-free reductant because technologies such as solar-driven electrolysis and supercritical water (scH2O) gasification enable sustainable production of molecular hydrogen (H2). We review the recent advances in engineering Ralstonia eutropha, the representative species of "Knallgas" bacteria, for utilizing CO2 and H2 to autotrophically produce 2,3-butanediol (2,3-BDO). This assessment is focused on state-of-the-art approaches for splitting H2 to supply energy in the form of ATP and NADH to power cellular reactions and employing the Calvin-Benson-Bassham cycle for CO2 fixation. Major challenges and opportunities for application and future perspectives are discussed in the context of developing other promising CO2 and H2-utilizing microorganisms, exemplified by Zymomonas mobilis.
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Affiliation(s)
- Hui Wei
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Wei Wang
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Yat-Chen Chou
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Michael E. Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Xiaowen Chen
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Yannick J. Bomble
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Min Zhang
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
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21
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Yu X, Catanescu CO, Bird RE, Satagopan S, Baum ZJ, Lotti Diaz LM, Zhou QA. Trends in Research and Development for CO 2 Capture and Sequestration. ACS OMEGA 2023; 8:11643-11664. [PMID: 37033841 PMCID: PMC10077574 DOI: 10.1021/acsomega.2c05070] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 03/03/2023] [Indexed: 06/19/2023]
Abstract
Technological and medical advances over the past few decades epitomize human capabilities. However, the increased life expectancies and concomitant land-use changes have significantly contributed to the release of ∼830 gigatons of CO2 into the atmosphere over the last three decades, an amount comparable to the prior two and a half centuries of CO2 emissions. The United Nations has adopted a pledge to achieve "net zero", i.e., yearly removing as much CO2 from the atmosphere as the amount emitted due to human activities, by the year 2050. Attaining this goal will require a concerted effort by scientists, policy makers, and industries all around the globe. The development of novel materials on industrial scales to selectively remove CO2 from mixtures of gases makes it possible to mitigate CO2 emissions using a multipronged approach. Broadly, the CO2 present in the atmosphere can be captured using materials and processes for biological, chemical, and geological technologies that can sequester CO2 while also reducing our dependence on fossil-fuel reserves. In this review, we used the curated literature available in the CAS Content Collection to present a systematic analysis of the various approaches taken by scientists and industrialists to restore carbon balance in the environment. Our analysis highlights the latest trends alongside the associated challenges.
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Calvey CH, Sànchez I Nogué V, White AM, Kneucker CM, Woodworth SP, Alt HM, Eckert CA, Johnson CW. Improving growth of Cupriavidus necator H16 on formate using adaptive laboratory evolution-informed engineering. Metab Eng 2023; 75:78-90. [PMID: 36368470 DOI: 10.1016/j.ymben.2022.10.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 10/28/2022] [Accepted: 10/30/2022] [Indexed: 11/11/2022]
Abstract
Conversion of CO2 to value-added products presents an opportunity to reduce GHG emissions while generating revenue. Formate, which can be generated by the electrochemical reduction of CO2, has been proposed as a promising intermediate compound for microbial upgrading. Here we present progress towards improving the soil bacterium Cupriavidus necator H16, which is capable of growing on formate as its sole source of carbon and energy using the Calvin-Benson-Bassham (CBB) cycle, as a host for formate utilization. Using adaptive laboratory evolution, we generated several isolates that exhibited faster growth rates on formate. The genomes of these isolates were sequenced, and resulting mutations were systematically reintroduced by metabolic engineering, to identify those that improved growth. The metabolic impact of several mutations was investigated further using RNA-seq transcriptomics. We found that deletion of a transcriptional regulator implicated in quorum sensing, PhcA, reduced expression of several operons and led to improved growth on formate. Growth was also improved by deleting large genomic regions present on the extrachromosomal megaplasmid pHG1, particularly two hydrogenase operons and the megaplasmid CBB operon, one of two copies present in the genome. Based on these findings, we generated a rationally engineered ΔphcA and megaplasmid-deficient strain that exhibited a 24% faster maximum growth rate on formate. Moreover, this strain achieved a 7% growth rate improvement on succinate and a 19% increase on fructose, demonstrating the broad utility of microbial genome reduction. This strain has the potential to serve as an improved microbial chassis for biological conversion of formate to value-added products.
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Affiliation(s)
- Christopher H Calvey
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Violeta Sànchez I Nogué
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Aleena M White
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Colin M Kneucker
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Sean P Woodworth
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Hannah M Alt
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Carrie A Eckert
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Christopher W Johnson
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA.
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23
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Recent progress in the engineering of C1-utilizing microbes. Curr Opin Biotechnol 2022; 78:102836. [PMID: 36334444 DOI: 10.1016/j.copbio.2022.102836] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/26/2022] [Accepted: 10/04/2022] [Indexed: 11/06/2022]
Abstract
The global climate crisis has led to the transition toward the sustainable production of chemicals and fuels with a low carbon footprint. Microbial utilization of one-carbon (C1) substrates, such as carbon dioxide, carbon monoxide, methane, formate, and methanol, may be a promising replacement for the current fossil fuel-based industry. However, natural C1-utilizing microbes are currently unsuitable for industrial applications because of their slow growth and low carbon conversion efficiency, which results in low productivity and yield. Here, we review the recent achievements in engineering C1-utilizing microbes with improved carbon assimilation efficiency and describe the development of synthetic microorganisms by introducing natural C1 assimilation pathways in non-C1-utilizing microbes. Finally, we outline the future directions for realizing the industrial potential of C1-utilizing microbes.
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24
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Kim S, Jang YJ, Gong G, Lee SM, Um Y, Kim KH, Ko JK. Engineering Cupriavidus necator H16 for enhanced lithoautotrophic poly(3-hydroxybutyrate) production from CO 2. Microb Cell Fact 2022; 21:231. [PMCID: PMC9636797 DOI: 10.1186/s12934-022-01962-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 10/13/2022] [Indexed: 11/06/2022] Open
Abstract
Background A representative hydrogen-oxidizing bacterium Cupriavidus necator H16 has attracted much attention as hosts to recycle carbon dioxide (CO2) into a biodegradable polymer, poly(R)-3-hydroxybutyrate (PHB). Although C. necator H16 has been used as a model PHB producer, the PHB production rate from CO2 is still too low for commercialization. Results Here, we engineer the carbon fixation metabolism to improve CO2 utilization and increase PHB production. We explore the possibilities to enhance the lithoautotrophic cell growth and PHB production by introducing additional copies of transcriptional regulators involved in Calvin Benson Bassham (CBB) cycle. Both cbbR and regA-overexpressing strains showed the positive phenotypes for 11% increased biomass accumulation and 28% increased PHB production. The transcriptional changes of key genes involved in CO2—fixing metabolism and PHB production were investigated. Conclusions The global transcriptional regulator RegA plays an important role in the regulation of carbon fixation and shows the possibility to improve autotrophic cell growth and PHB accumulation by increasing its expression level. This work represents another step forward in better understanding and improving the lithoautotrophic PHB production by C. necator H16. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-022-01962-7.
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Affiliation(s)
- Soyoung Kim
- grid.35541.360000000121053345Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea
| | - Yong Jae Jang
- grid.35541.360000000121053345Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea
| | - Gyeongtaek Gong
- grid.35541.360000000121053345Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea ,grid.412786.e0000 0004 1791 8264Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul, 02792 Republic of Korea
| | - Sun-Mi Lee
- grid.35541.360000000121053345Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea ,grid.412786.e0000 0004 1791 8264Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul, 02792 Republic of Korea
| | - Youngsoon Um
- grid.35541.360000000121053345Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea ,grid.412786.e0000 0004 1791 8264Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul, 02792 Republic of Korea
| | - Kyoung Heon Kim
- grid.222754.40000 0001 0840 2678Department of Biotechnology, Graduate School, Korea University, Seoul, 02841 Republic of Korea
| | - Ja Kyong Ko
- grid.35541.360000000121053345Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea ,grid.412786.e0000 0004 1791 8264Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul, 02792 Republic of Korea
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Qiao W, Xu S, Liu Z, Fu X, Zhao H, Shi S. Challenges and opportunities in C1-based biomanufacturing. BIORESOURCE TECHNOLOGY 2022; 364:128095. [PMID: 36220528 DOI: 10.1016/j.biortech.2022.128095] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/03/2022] [Accepted: 10/05/2022] [Indexed: 06/16/2023]
Abstract
The intensifying impact of green-house gas (GHG) emission on environment and climate change has attracted increasing attention, and biorefinery represents one of the most effective routes for reducing GHG emissions from human activities. However, this requires a shift for microbial fermentation from the current use of sugars to the use of biomass, and even better to the primary fixation of single carbon (C1) compounds. Here how microorganisms can be engineered for fixation and conversion of C1 compounds into metabolites that can serve as fuels and platform chemicals are reviewed. Meanwhile, key factors for utilization of these different pathways are discussed, followed by challenges and barriers for the development of C1-based biorefinery.
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Affiliation(s)
- Weibo Qiao
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Shijie Xu
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Zihe Liu
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xiaoying Fu
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Shuobo Shi
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China.
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Salusjärvi L, Ojala L, Peddinti G, Lienemann M, Jouhten P, Pitkänen JP, Toivari M. Production of biopolymer precursors beta-alanine and L-lactic acid from CO2 with metabolically versatile Rhodococcus opacus DSM 43205. Front Bioeng Biotechnol 2022; 10:989481. [PMID: 36281430 PMCID: PMC9587121 DOI: 10.3389/fbioe.2022.989481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 09/16/2022] [Indexed: 11/18/2022] Open
Abstract
Hydrogen oxidizing autotrophic bacteria are promising hosts for conversion of CO2 into chemicals. In this work, we engineered the metabolically versatile lithoautotrophic bacterium R. opacus strain DSM 43205 for synthesis of polymer precursors. Aspartate decarboxylase (panD) or lactate dehydrogenase (ldh) were expressed for beta-alanine or L-lactic acid production, respectively. The heterotrophic cultivations on glucose produced 25 mg L−1 beta-alanine and 742 mg L−1 L-lactic acid, while autotrophic cultivations with CO2, H2, and O2 resulted in the production of 1.8 mg L−1 beta-alanine and 146 mg L−1 L-lactic acid. Beta-alanine was also produced at 345 μg L−1 from CO2 in electrobioreactors, where H2 and O2 were provided by water electrolysis. This work demonstrates that R. opacus DSM 43205 can be engineered to produce chemicals from CO2 and provides a base for its further metabolic engineering.
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Affiliation(s)
- Laura Salusjärvi
- VTT Technical Research Centre of Finland Ltd., Espoo, Finland
- *Correspondence: Laura Salusjärvi,
| | - Leo Ojala
- VTT Technical Research Centre of Finland Ltd., Espoo, Finland
| | - Gopal Peddinti
- VTT Technical Research Centre of Finland Ltd., Espoo, Finland
| | | | - Paula Jouhten
- Department of Bioproducts and Biosystems, Aalto University, Espoo, Finland
| | | | - Mervi Toivari
- VTT Technical Research Centre of Finland Ltd., Espoo, Finland
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27
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Lin L, Huang H, Zhang X, Dong L, Chen Y. Hydrogen-oxidizing bacteria and their applications in resource recovery and pollutant removal. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 835:155559. [PMID: 35483467 DOI: 10.1016/j.scitotenv.2022.155559] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/16/2022] [Accepted: 04/23/2022] [Indexed: 06/14/2023]
Abstract
Hydrogen oxidizing bacteria (HOB), a type of chemoautotroph, are a group of bacteria from different genera that share the ability to oxidize H2 and fix CO2 to provide energy and synthesize cellular material. Recently, HOB have received growing attention due to their potential for CO2 capture and waste recovery. This review provides a comprehensive overview of the biological characteristics of HOB and their application in resource recovery and pollutant removal. Firstly, the enzymes, genes and corresponding regulation systems responsible for the key metabolic processes of HOB are discussed in detail. Then, the enrichment and cultivation methods including the coupled water splitting-biosynthetic system cultivation, mixed cultivation and two-stage cultivation strategies for HOB are summarized, which is the critical prerequisite for their application. On the basis, recent advances of HOB application in the recovery of high-value products and the removal of pollutants are presented. Finally, the key points for future investigation are proposed that more attention should be paid to the main limitations in the large-scale industrial application of HOB, including the mass transfer rate of the gases, the safety of the production processes and products, and the commercial value of the products.
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Affiliation(s)
- Lin Lin
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Haining Huang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Xin Zhang
- Shanghai Municipal Engineering Design Institute (Group) Co. LTD, 901 Zhongshan North Second Rd, Shanghai 200092, China
| | - Lei Dong
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Shanghai Municipal Engineering Design Institute (Group) Co. LTD, 901 Zhongshan North Second Rd, Shanghai 200092, China
| | - Yinguang Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
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Hydrogen Production and Storage: Analysing Integration of Photoelectrolysis, Electron Harvesting Lignocellulose, and Atmospheric Carbon Dioxide-Fixing Biosynthesis. ENERGIES 2022. [DOI: 10.3390/en15155486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Green hydrogen from photocatalytic water-splitting and photocatalytic lignocellulosic reforming is a significant proposition for renewable energy storage in global net-zero policies and strategies. Although photocatalytic water-splitting and photocatalytic lignocellulosic reforming have been investigated, their integration is novel. Furthermore, biosynthesis can store the evolved hydrogen and fix the atmospheric carbon dioxide in a biocathode chamber. The biocathode chamber is coupled to the combined photocatalytic water-splitting and lignocellulose oxidation in an anode chamber. This integrated system of anode and biocathode mimics a (bio)electrosynthesis system. A visible solar radiation-driven novel hybrid system comprising photocatalytic water-splitting, lignocellulose oxidation, and atmospheric CO2 fixation is, thus, investigated. It must be noted that there is no technology for reducing atmospheric CO2 concentration. Thus, our novel intensified technology enables renewable and sustainable hydrogen economy and direct CO2 capture from air to confront climate change impact. The photocatalytic anode considered is CdS nanocomposites that give a low absorption onset (200 nm), high absorbance range (200–800 nm), and narrow bandgap (1.58–2.4 V). The biocathode considered is Ralstonia eutropha H16 interfaced with photocatalytic lignocellulosic oxidation and a water-splitting anode. The biocathode undergoes autotrophic metabolism fixing atmospheric CO2 and hydrogen to poly(3-hydroxybutyrate) biosynthesis. As the hydrogen evolved can be readily stored, the electron–hole pair can be separated, increasing the hydrogen evolution efficiency. Although there are many experimental studies, this study for the first time sets the maximum theoretical efficiency target from mechanistic deductions of practical insights. Compared to physical/physicochemical absorption with solvent recovery to capture CO2, the photosynthetic CO2 capture efficiency is 51%. The maximum solar-to-hydrogen generation efficiency is 33%. Lignocelluloses participate in hydrogen evolution by (1–4)-glycosidic bond decomposition, releasing accessible sugar monomers or monosaccharides forming a Cd–O–R bond with the CdS/CdOx nanocomposite surface used as a photocatalyst/semiconductor, leading to CO32− in oxidised carboxylic acid products. Lignocellulose dosing as an oxidising agent can increase the extent of water-splitting. The mechanistic analyses affirm the criticality of lignocellulose oxidation in photocatalytic hydrogen evolution. The critical conditions for success are increasing the alcohol neutralising agent’s strength, increasing the selective (ligno)cellulose dosing, broadening the hybrid nanostructure of the photocatalyst/semiconductor, enhancing the visible-light range absorbance, and increasing the solar energy utilisation efficiency.
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29
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Zhang L, Jiang Z, Tsui TH, Loh KC, Dai Y, Tong YW. A Review on Enhancing Cupriavidus necator Fermentation for Poly(3-hydroxybutyrate) (PHB) Production From Low-Cost Carbon Sources. Front Bioeng Biotechnol 2022; 10:946085. [PMID: 35928944 PMCID: PMC9343952 DOI: 10.3389/fbioe.2022.946085] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022] Open
Abstract
In the context of a circular economy, bioplastic production using biodegradable materials such as poly(3-hydroxybutyrate) (PHB) has been proposed as a promising solution to fundamentally solve the disposal issue of plastic waste. PHB production techniques through fermentation of PHB-accumulating microbes such as Cupriavidus necator have been revolutionized over the past several years with the development of new strategies such as metabolic engineering. This review comprehensively summarizes the latest PHB production technologies via Cupriavidus necator fermentation. The mechanism of the biosynthesis pathway for PHB production was first assessed. PHB production efficiencies of common carbon sources, including food waste, lignocellulosic materials, glycerol, and carbon dioxide, were then summarized and critically analyzed. The key findings in enhancing strategies for PHB production in recent years, including pre-treatment methods, nutrient limitations, feeding optimization strategies, and metabolism engineering strategies, were summarized. Furthermore, technical challenges and future prospects of strategies for enhanced production efficiencies of PHB were also highlighted. Based on the overview of the current enhancing technologies, more pilot-scale and larger-scale tests are essential for future implementation of enhancing strategies in full-scale biogas plants. Critical analyses of various enhancing strategies would facilitate the establishment of more sustainable microbial fermentation systems for better waste management and greater efficiency of PHB production.
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Affiliation(s)
- Le Zhang
- NUS Environmental Research Institute, National University of Singapore, Singapore, Singapore
- Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), Singapore, Singapore
| | - Zicheng Jiang
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore
| | - To-Hung Tsui
- NUS Environmental Research Institute, National University of Singapore, Singapore, Singapore
- Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), Singapore, Singapore
| | - Kai-Chee Loh
- Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), Singapore, Singapore
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore
| | - Yanjun Dai
- Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), Singapore, Singapore
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yen Wah Tong
- NUS Environmental Research Institute, National University of Singapore, Singapore, Singapore
- Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), Singapore, Singapore
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore
- *Correspondence: Yen Wah Tong,
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30
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Sheldon RA, Brady D. Green Chemistry, Biocatalysis, and the Chemical Industry of the Future. CHEMSUSCHEM 2022; 15:e202102628. [PMID: 35026060 DOI: 10.1002/cssc.202102628] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 01/11/2022] [Indexed: 06/14/2023]
Abstract
In the movement to decarbonize our economy and move away from fossil fuels we will need to harness the waste products of our activities, such as waste lignocellulose, methane, and carbon dioxide. Our wastes need to be integrated into a circular economy where used products are recycled into a manufacturing carbon cycle. Key to this will be the recycling of plastics at the resin and monomer levels. Biotechnology is well suited to a future chemical industry that must adapt to widely distributed and diverse biological chemical feedstocks. Our increasing mastery of biotechnology is allowing us to develop enzymes and organisms that can synthesize a widening selection of desirable bulk chemicals, including plastics, at commercially viable productivities. Integration of bioreactors with electrochemical systems will permit new production opportunities with enhanced productivities and the advantage of using a low-carbon electricity from renewable and sustainable sources.
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Affiliation(s)
- Roger A Sheldon
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, 1 Jan Smuts Avenue, Braamfontein, Johannesburg, 2000, South Africa
- Department of Biotechnology, Delft University of Technology, Section BOC, van der Maasweg 9, 2629 HZ, Delft, Netherlands
| | - Dean Brady
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, 1 Jan Smuts Avenue, Braamfontein, Johannesburg, 2000, South Africa
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31
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Recycling carbon for sustainable protein production using gas fermentation. Curr Opin Biotechnol 2022; 76:102723. [PMID: 35487158 DOI: 10.1016/j.copbio.2022.102723] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 02/23/2022] [Accepted: 03/17/2022] [Indexed: 02/07/2023]
Abstract
Current food production practices contribute significantly to climate change. To transition into a sustainable future, a combination of new food habits and a radical food production innovation must occur. Single-cell protein from microbial fermentation can profoundly impact sustainability. This review paper explores opportunities offered by gas fermentation to completely replace our reliance on fossil fuels for the production of food. Together with synthetic biology, designed microbial proteins from gas fermentation have the potential to reduce our dependence on fossil fuels and make food production more sustainable.
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Abstract
Carbon dioxide is a major greenhouse gas, and its fixation and transformation are receiving increasing attention. Biofixation of CO2 is an eco–friendly and efficient way to reduce CO2, and six natural CO2 fixation pathways have been identified in microorganisms and plants. In this review, the six pathways along with the most recent identified variant pathway were firstly comparatively characterized. The key metabolic process and enzymes of the CO2 fixation pathways were also summarized. Next, the enzymes of Rubiscos, biotin-dependent carboxylases, CO dehydrogenase/acetyl-CoA synthase, and 2-oxoacid:ferredoxin oxidoreductases, for transforming inorganic carbon (CO2, CO, and bicarbonate) to organic chemicals, were specially analyzed. Then, the factors including enzyme properties, CO2 concentrating, energy, and reducing power requirements that affect the efficiency of CO2 fixation were discussed. Recent progress in improving CO2 fixation through enzyme and metabolic engineering was then summarized. The artificial CO2 fixation pathways with thermodynamical and/or energetical advantages or benefits and their applications in biosynthesis were included as well. The challenges and prospects of CO2 biofixation and conversion are discussed.
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Strittmatter CS, Eggers J, Biesgen V, Pauels I, Becker F, Steinbüchel A. The reliance of glycerol utilization by Cupriavidus necator on CO 2 fixation and improved glycerol catabolism. Appl Microbiol Biotechnol 2022; 106:2541-2555. [PMID: 35325274 DOI: 10.1007/s00253-022-11842-0] [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] [Received: 01/21/2022] [Revised: 02/15/2022] [Accepted: 02/17/2022] [Indexed: 11/29/2022]
Abstract
While crude glycerol is a cheap carbon source for industrial-scale cultivation of microorganisms, its application relies on fast growth and conversion. The biopolymer producing Cupriavidus necator H16 (synonym: Ralstonia eutropha H16) grows poorly on glycerol. The heterologous expression of glycerol facilitator glpF, glycerol kinase glpK, and glycerol dehydrogenase glpD from E. coli accelerated the growth considerably. The naturally occurring glycerol utilization is inhibited by low glycerol kinase activity. A limited heterotrophic growth promotes the dependency on autotrophic growth by carbon dioxide (CO2) fixation and refixation. As mixotrophic growth occurs in the wildtype due to low consumption rates of glycerol, CO2 fixation by the Calvin-Benson-Bassham (CBB) cycle is essential. The deletion of both cbbX copies encoding putative RuBisCO-activases (AAA + ATPase) resulted in a sharp slowdown of growth and glycerol consumption. Activase activity is necessary for functioning carboxylation by RuBisCO. Each of the two copies compensates for the loss of the other, as suggested by observed expression levels. The strong tendency towards autotrophy supports previous investigations of glycerol growth and emphasizes the versatility of the metabolism of C. necator H16. Mixotrophy with glycerol-utilization and CO2 fixation with a high dependence on the CBB is automatically occurring unless transportation and degradation of glycerol are optimized. Parallel engineering of CO2 fixation and glycerol degradation is suggested towards application for value-added production from crude glycerol. KEY POINTS: • Growth on glycerol is highly dependent on efficient carbon fixation via CBB cycle. • CbbX is essential for the efficiency of RuBisCO in C. necator H16. • Expression of glycerol degradation pathway enzymes accelerates glycerol utilization.
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Affiliation(s)
- Carl Simon Strittmatter
- Insitut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universtität Münster, Münster, Germany
| | - Jessica Eggers
- Insitut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universtität Münster, Münster, Germany
| | - Vanessa Biesgen
- Insitut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universtität Münster, Münster, Germany
| | - Inga Pauels
- Insitut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universtität Münster, Münster, Germany
| | - Florian Becker
- Insitut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universtität Münster, Münster, Germany
| | - Alexander Steinbüchel
- Insitut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universtität Münster, Münster, Germany. .,Environmental Science Department, King Abdulaziz University, Jeddah, Saudi Arabia.
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García JL, Galán B. Integrating greenhouse gas capture and C1 biotechnology: a key challenge for circular economy. Microb Biotechnol 2021; 15:228-239. [PMID: 34905295 PMCID: PMC8719819 DOI: 10.1111/1751-7915.13991] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 11/27/2021] [Indexed: 12/02/2022] Open
Affiliation(s)
- José L García
- Environmental Biotechnology Laboratory, Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas Margarita Salas (CIB-MS, CSIC), Madrid, Spain
| | - Beatriz Galán
- Environmental Biotechnology Laboratory, Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas Margarita Salas (CIB-MS, CSIC), Madrid, Spain
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Lee J, Park HJ, Moon M, Lee JS, Min K. Recent progress and challenges in microbial polyhydroxybutyrate (PHB) production from CO 2 as a sustainable feedstock: A state-of-the-art review. BIORESOURCE TECHNOLOGY 2021; 339:125616. [PMID: 34304096 DOI: 10.1016/j.biortech.2021.125616] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 05/05/2023]
Abstract
The recalcitrance of petroleum-based plastics causes severe environmental problems and has accelerated research into production of biodegradable polymers from inexpensive and sustainable feedstocks. Various microorganisms are capable of producing Polyhydroxybutyrate (PHB), a representative biodegradable polymer, under nutrient-limited conditions, among which CO2-utilizing microorganisms are of primary interest. Herein, we discuss recent progress on bacterial strains including proteobacteria, purple non-sulfur bacteria, and cyanobacteria in terms of CO2-containing carbon sources, PHB-production capability, and genetic modification. In addition, this review introduces recent technical approaches used to improve PHB production from CO2 such as two-stage bioprocesses and bioelectrochemical systems. Challenges and future perspectives for the development of economically feasible PHB production are also discussed. Finally, this review might provide insights into the construction of a closed-carbon-loop to cope with climate change.
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Affiliation(s)
- Jiye Lee
- Gwangju Bio/Energy R&D Center, Korea Institute of Energy Research (KIER), Gwangju 61003, Republic of Korea
| | - Hyun June Park
- Department of Biotechnology, Duksung Women's University, Seoul 01369, Republic of Korea
| | - Myounghoon Moon
- Gwangju Bio/Energy R&D Center, Korea Institute of Energy Research (KIER), Gwangju 61003, Republic of Korea
| | - Jin-Suk Lee
- Gwangju Bio/Energy R&D Center, Korea Institute of Energy Research (KIER), Gwangju 61003, Republic of Korea
| | - Kyoungseon Min
- Gwangju Bio/Energy R&D Center, Korea Institute of Energy Research (KIER), Gwangju 61003, Republic of Korea.
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36
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Ma Z, Liu D, Liu M, Cao Y, Song H. From CO<sub>2</sub> to high value-added products: Advances on carbon sequestration by <italic>Ralstonia eutropha</italic> H16. CHINESE SCIENCE BULLETIN-CHINESE 2021. [DOI: 10.1360/tb-2021-0584] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Chawley P, Rana A, Jagadevan S. Envisioning role of ammonia oxidizing bacteria in bioenergy production and its challenges: a review. Crit Rev Biotechnol 2021; 42:931-952. [PMID: 34641754 DOI: 10.1080/07388551.2021.1976099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Ammonia oxidizing bacteria (AOB) play a key role in the biological oxidation of ammonia to nitrite and mark their significance in the biogeochemical nitrogen cycle. There has been significant development in harnessing the ammonia oxidizing potential of AOB in the past few decades. However, very little is known about the potential applications of AOB in the bioenergy sector. As alternate sources of energy represent a thrust area for environmental sustainability, the role of AOB in bioenergy production becomes a significant area of exploration. This review highlights the role of AOB in bioenergy production and emphasizes the understanding of the genetic make-up and key cellular biochemical reactions occurring in AOB, thereby leading to the exploration of its various functional aspects. Recent outcomes in novel ammonia/nitrite oxidation steps occurring in a model AOB - Nitrosomonas europaea propel us to explore several areas of environmental implementation. Here we present the significant role of AOB in microbial fuel cells (MFC) where Nitrosomonas sp. play both anodic and cathodic functions in the generation of bioelectricity. This review also presents the potential role of AOB in curbing fuel demand by producing alternative liquid fuel such as methanol and biodiesel. Herein, the multiple roles of AOB in bioenergy production namely: bioelectricity generation, bio-methanol, and biodiesel production have been presented.
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Affiliation(s)
- Parmita Chawley
- Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand, India
| | - Anu Rana
- Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand, India
| | - Sheeja Jagadevan
- Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand, India
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38
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Microbial cell factories for the production of polyhydroxyalkanoates. Essays Biochem 2021; 65:337-353. [PMID: 34132340 DOI: 10.1042/ebc20200142] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/14/2021] [Accepted: 05/26/2021] [Indexed: 12/20/2022]
Abstract
Pollution caused by persistent petro-plastics is the most pressing problem currently, with 8 million tons of plastic waste dumped annually in the oceans. Plastic waste management is not systematized in many countries, because it is laborious and expensive with secondary pollution hazards. Bioplastics, synthesized by microorganisms, are viable alternatives to petrochemical-based thermoplastics due to their biodegradable nature. Polyhydroxyalkanoates (PHAs) are a structurally and functionally diverse group of storage polymers synthesized by many microorganisms, including bacteria and Archaea. Some of the most important PHA accumulating bacteria include Cupriavidus necator, Burkholderia sacchari, Pseudomonas sp., Bacillus sp., recombinant Escherichia coli, and certain halophilic extremophiles. PHAs are synthesized by specialized PHA polymerases with assorted monomers derived from the cellular metabolite pool. In the natural cycle of cellular growth, PHAs are depolymerized by the native host for carbon and energy. The presence of these microbial PHA depolymerases in natural niches is responsible for the degradation of bioplastics. Polyhydroxybutyrate (PHB) is the most common PHA with desirable thermoplastic-like properties. PHAs have widespread applications in various industries including biomedicine, fine chemicals production, drug delivery, packaging, and agriculture. This review provides the updated knowledge on the metabolic pathways for PHAs synthesis in bacteria, and the major microbial hosts for PHAs production. Yeasts are presented as a potential candidate for industrial PHAs production, with their high amenability to genetic engineering and the availability of industrial-scale technology. The major bottlenecks in the commercialization of PHAs as an alternative for plastics and future perspectives are also critically discussed.
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39
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Panich J, Fong B, Singer SW. Metabolic Engineering of Cupriavidus necator H16 for Sustainable Biofuels from CO 2. Trends Biotechnol 2021; 39:412-424. [PMID: 33518389 DOI: 10.1016/j.tibtech.2021.01.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 02/08/2023]
Abstract
Decelerating global warming is one of the predominant challenges of our time and will require conversion of CO2 to usable products and commodity chemicals. Of particular interest is the production of fuels, because the transportation sector is a major source of CO2 emissions. Here, we review recent technological advances in metabolic engineering of the hydrogen-oxidizing bacterium Cupriavidus necator H16, a chemolithotroph that naturally consumes CO2 to generate biomass. We discuss recent successes in biofuel production using this organism, and the implementation of electrolysis/artificial photosynthesis approaches that enable growth of C. necator using renewable electricity and CO2. Last, we discuss prospects of improving the nonoptimal growth of C. necator in ambient concentrations of CO2.
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Affiliation(s)
- Justin Panich
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
| | - Bonnie Fong
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Steven W Singer
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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