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Paredes-Barrada M, Kopsiaftis P, Claassens NJ, van Kranenburg R. Parageobacillus thermoglucosidasius as an emerging thermophilic cell factory. Metab Eng 2024; 83:39-51. [PMID: 38490636 DOI: 10.1016/j.ymben.2024.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 02/21/2024] [Accepted: 03/05/2024] [Indexed: 03/17/2024]
Abstract
Parageobacillus thermoglucosidasius is a thermophilic and facultatively anaerobic microbe, which is emerging as one of the most promising thermophilic model organisms for metabolic engineering. The use of thermophilic microorganisms for industrial bioprocesses provides the advantages of increased reaction rates and reduced cooling costs for bioreactors compared to their mesophilic counterparts. Moreover, it enables starch or lignocellulose degradation and fermentation to occur at the same temperature in a Simultaneous Saccharification and Fermentation (SSF) or Consolidated Bioprocessing (CBP) approach. Its natural hemicellulolytic capabilities and its ability to convert CO to metabolic energy make P. thermoglucosidasius a potentially attractive host for bio-based processes. It can effectively degrade hemicellulose due to a number of hydrolytic enzymes, carbohydrate transporters, and regulatory elements coded from a genomic cluster named Hemicellulose Utilization (HUS) locus. The growing availability of effective genetic engineering tools in P. thermoglucosidasius further starts to open up its potential as a versatile thermophilic cell factory. A number of strain engineering examples showcasing the potential of P. thermoglucosidasius as a microbial chassis for the production of bulk and fine chemicals are presented along with current research bottlenecks. Ultimately, this review provides a holistic overview of the distinct metabolic characteristics of P. thermoglucosidasius and discusses research focused on expanding the native metabolic boundaries for the development of industrially relevant strains.
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Affiliation(s)
- Miguel Paredes-Barrada
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | | | - Nico J Claassens
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
| | - Richard van Kranenburg
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands; Corbion, Arkelsedijk 46, 4206 AC, Gorinchem, The Netherlands.
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Kurashiki R, Koyama K, Sakaguchi Y, Okumura Y, Ohshiro T, Suzuki H. Development of a thermophilic host-vector system for the production of recombinant proteins at elevated temperatures. Appl Microbiol Biotechnol 2023; 107:7475-7488. [PMID: 37755510 DOI: 10.1007/s00253-023-12805-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 09/08/2023] [Accepted: 09/18/2023] [Indexed: 09/28/2023]
Abstract
Geobacillus spp. are moderate thermophiles that can efficiently produce recombinant proteins. Considering the protein production exhibited by these species, we searched for robust promoters in Geobacillus kaustophilus HTA426. Transcriptome data revealed that several genes were highly expressed during the proliferative phase; their promoters were characterized using reporter assays with Venus fluorescent protein (VFP). The results suggested that the cspD promoter (PcspD) directed robust vfp expression at 60°C in G. kaustophilus. Although cspD potentially encodes a cold-shock protein, PcspD functioned at elevated temperatures. The promoter strongly functioned even in Escherichia coli; this prevented the cloning of some genes (e.g., vfp) downstream of it on a plasmid vector via E. coli-based genetic manipulation. Consequently, we generated a mutated PcspD that functioned inefficiently in E. coli and constructed the pGKE124 plasmid using the mutant promoter. The plasmid could carry vfp in E. coli and afford the production of VFP in G. kaustophilus at a yield of 390 mg/L. pGKE124 directed a similar production in other thermophilic species; the highest yield was observed in Geobacillus thermodenitrificans K1041. Several proteins could be produced using a system involving G. thermodenitrificans K1041 and pGKE124. Notably, the extracellular production of xylanase at a yield of 1 g/L was achieved using this system. Although the leaky production of nonsecretory proteins was observed, we developed a simple process to collectively purify recombinant proteins from the intracellular and extracellular fractions. The findings presented there propose an effective host-vector system for the production of recombinant proteins at elevated temperatures. KEY POINTS: • A thermophilic system to produce recombinant proteins was constructed. • The system produced diverse proteins using inexpensive media at elevated temperatures. • The system produced an extracellular protein at a yield of 1 g/L of culture.
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Affiliation(s)
- Ryota Kurashiki
- Department of Engineering, Graduate School of Sustainability Science, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan
| | - Kosuke Koyama
- Department of Engineering, Graduate School of Sustainability Science, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan
| | - Yukina Sakaguchi
- Faculty of Engineering, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan
| | - Yuta Okumura
- Department of Engineering, Graduate School of Sustainability Science, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan
| | - Takashi Ohshiro
- Faculty of Engineering, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan
- Center for Research on Green Sustainable Chemistry, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan
| | - Hirokazu Suzuki
- Faculty of Engineering, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan.
- Center for Research on Green Sustainable Chemistry, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan.
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Millgaard M, Bidart GN, Pogrebnyakov I, Nielsen AT, Welner DH. An improved integrative GFP-based vector for genetic engineering of Parageobacillus thermoglucosidasius facilitates the identification of a key sporulation regulator. AMB Express 2023; 13:44. [PMID: 37154828 PMCID: PMC10167077 DOI: 10.1186/s13568-023-01544-9] [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: 02/13/2023] [Accepted: 04/05/2023] [Indexed: 05/10/2023] Open
Abstract
Parageobacillus thermoglucosidasius is a thermophilic Gram-positive bacterium, which is a promising host organism for sustainable bio-based production processes. However, to take full advantage of the potential of P. thermoglucosidasius, more efficient tools for genetic engineering are required. The present study describes an improved shuttle vector, which speeds up recombination-based genomic modification by incorporating a thermostable sfGFP variant into the vector backbone. This additional selection marker allows for easier identification of recombinants, thereby removing the need for several culturing steps. The novel GFP-based shuttle is therefore capable of facilitating faster metabolic engineering of P. thermoglucosidasius through genomic deletion, integration, or exchange. To demonstrate the efficiency of the new system, the GFP-based vector was utilised for deletion of the spo0A gene in P. thermoglucosidasius DSM2542. This gene is known to be a key regulator of sporulation in Bacillus subtilis, and it was therefore hypothesised that the deletion of spo0A in P. thermoglucosiadius would produce an analogous sporulation-inhibited phenotype. Subsequent analyses of cell morphology and culture heat resistance suggests that the P. thermoglucosidasius ∆spo0A strain is sporulation-deficient. This strain may be an excellent starting point for future cell factory engineering of P. thermoglucosidasius, as the formation of endospores is normally not a desired trait in large-scale production.
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Affiliation(s)
- Marie Millgaard
- The Novo Nordisk Foundation Center for Biosustainability, Building 220, Kemitorvet, 2800, Kgs. Lyngby, Denmark
| | - Gonzalo Nahuel Bidart
- The Novo Nordisk Foundation Center for Biosustainability, Building 220, Kemitorvet, 2800, Kgs. Lyngby, Denmark
| | - Ivan Pogrebnyakov
- The Novo Nordisk Foundation Center for Biosustainability, Building 220, Kemitorvet, 2800, Kgs. Lyngby, Denmark
| | - Alex Toftgaard Nielsen
- The Novo Nordisk Foundation Center for Biosustainability, Building 220, Kemitorvet, 2800, Kgs. Lyngby, Denmark.
| | - Ditte Hededam Welner
- The Novo Nordisk Foundation Center for Biosustainability, Building 220, Kemitorvet, 2800, Kgs. Lyngby, Denmark.
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New Platform for Screening Genetic Libraries at Elevated Temperatures: Biological and Genomic Information and Genetic Tools of Geobacillus thermodenitrificans K1041. Appl Environ Microbiol 2022; 88:e0105122. [PMID: 36069579 PMCID: PMC9499010 DOI: 10.1128/aem.01051-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Geobacillus thermodenitrificans K1041 is an unusual thermophile that is highly transformable via electroporation, making it a promising host for screening genetic libraries at elevated temperatures. In this study, we determined its biological properties, draft genome sequence, and effective vectors and also optimized the electroporation procedures in an effort to enhance its utilization. The organism exhibited swarming motility but not detectable endospore formation, and growth was rapid at 60°C under neutral and relatively low-salt conditions. Although the cells showed negligible acceptance of shuttle plasmids from general strains of Escherichia coli, methylation-controlled plasmids from dam mutant strains were efficiently accepted, suggesting circumvention of a restriction-modification system in G. thermodenitrificans K1041. We optimized the electroporation procedure to achieve efficiencies of 103 to 105 CFU/μg for five types of plasmids, which exhibited the different copy numbers and segregational stabilities in G. thermodenitrificans K1041. Some sets of plasmids were compatible. Moreover, we observed substantial plasmid-directed production of heterologous proteins in the intracellular or extracellular environments. Our successful construction of a library of promoter mutants using K1041 cells as hosts and subsequent screening at elevated temperatures to identify improved promoters revealed that G. thermodenitrificans K1041 was practical as a library host. The draft genomic sequence of the organism contained 3,384 coding genes, including resA and mcrB genes, which are involved in restriction-modification systems. Further examination revealed that in-frame deletions of resA increased transformation efficiencies, but mcrB deletion had no effect. The ΔresA mutant exhibited transformation efficiencies of >105 CFU/μg for some plasmids. IMPORTANCE Geobacillus thermodenitrificans K1041 has yet to be fully characterized. Although it is transformable via electroporation, it rarely accepts Escherichia coli-derived plasmids. This study clarified the biological and genomic properties of G. thermodenitrificans K1041. Additionally, we developed an electroporation procedure resulting in efficient acceptance of E. coli-derived plasmids. This procedure produced transformants using small amounts of plasmids immediately after the ligation reaction. Thus, G. thermodenitrificans K1041 was identified as a host for screening promoter mutants at elevated temperatures. Furthermore, because this strain efficiently produced heterologous proteins, it could serve as a host for screening thermostable proteins encoded in random mutant libraries or metagenomes. We also generated a ΔresA mutant that exhibited transformation efficiencies of >105 CFU/μg, which were highest in cases of electroporation-based transformation of Geobacillus spp. with E. coli-derived plasmids. Our findings provide a new platform for screening diverse genetic libraries at elevated temperatures.
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Abstract
Synthetic biology applications rely on a well-characterized set of microbial strains, with an established toolbox of molecular biology methods for their genetic manipulation. Since there are no thermophiles with such attributes, most biotechnology and synthetic biology studies use organisms that grow in the mesophilic temperature range. As a result, thermophiles, a heterogenous group of microbes that thrive at high (>50 °C) temperatures, are largely overlooked, with respect to their biotechnological potential, even though they share several favorable traits. Thermophilic bacteria tend to grow at higher rates compared to their mesophilic counterparts, while their growth has lower cooling requirements and is less prone to contamination. Over the last few years, there has been renewed interest in developing tools and methods for thermophile bioengineering. In this perspective, we explain why it is a good idea to invest time and effort into developing a thermophilic synthetic biology direction, which is the state of the art, and why we think that the implementation of a thermophilic synthetic biology platform—a thermochassis—will take synthetic biology to the extremes.
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Liang J, Roberts A, van Kranenburg R, Bolhuis A, Leak DJ. Relaxed control of sugar utilization in Parageobacillus thermoglucosidasius DSM 2542. Microbiol Res 2021; 256:126957. [PMID: 35032723 DOI: 10.1016/j.micres.2021.126957] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 11/22/2021] [Accepted: 12/27/2021] [Indexed: 01/08/2023]
Abstract
Though carbon catabolite repression (CCR) has been intensively studied in some more characterised organisms, there is a lack of information of CCR in thermophiles. In this work, CCR in the thermophile, Parageobacillus thermoglucosidasius DSM 2542 has been studied during growth on pentose sugars in the presence of glucose. Physiological studies under fermentative conditions revealed a loosely controlled CCR when DSM 2542 was grown in minimal medium supplemented with a mixture of glucose and xylose. This atypical CCR pattern was also confirmed by studying xylose isomerase expression level by qRT-PCR. Fortuitously, the pheB gene, which encodes catechol 2, 3-dioxygenase was found to have a cre site highly similar to the consensus catabolite-responsive element (cre) at its 3' end and was used to confirm that expression of pheB from a plasmid was under stringent CCR control. Bioinformatic analysis suggested that the CCR regulation of xylose metabolism in P. thermoglucosidasius DSM 2542 might occur primarily via control of expression of pentose transporter operons. Relaxed control of sugar utilization might reflect a lower affinity of the CcpA-HPr (Ser46-P) or CcpA-Crh (Ser46-P) complexes to the cre(s) in these operons.
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Affiliation(s)
- Jinghui Liang
- Department of Biology and Biochemistry, University of Bath, UK.
| | - Adam Roberts
- Department of Biology and Biochemistry, University of Bath, UK
| | - Richard van Kranenburg
- Laboratory of Microbiology, Wageningen University, The Netherlands; Corbion, Arkelsedijk 46, 4206 AC, Gorinchem, The Netherlands
| | - Albert Bolhuis
- Department of Pharmacy and Pharmacology, University of Bath, UK
| | - David J Leak
- Department of Biology and Biochemistry, University of Bath, UK
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Mol V, Bennett M, Sánchez BJ, Lisowska BK, Herrgård MJ, Nielsen AT, Leak DJ, Sonnenschein N. Genome-scale metabolic modeling of P. thermoglucosidasius NCIMB 11955 reveals metabolic bottlenecks in anaerobic metabolism. Metab Eng 2021; 65:123-134. [PMID: 33753231 DOI: 10.1016/j.ymben.2021.03.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 03/01/2021] [Indexed: 12/27/2022]
Abstract
Parageobacillus thermoglucosidasius represents a thermophilic, facultative anaerobic bacterial chassis, with several desirable traits for metabolic engineering and industrial production. To further optimize strain productivity, a systems level understanding of its metabolism is needed, which can be facilitated by a genome-scale metabolic model. Here, we present p-thermo, the most complete, curated and validated genome-scale model (to date) of Parageobacillus thermoglucosidasius NCIMB 11955. It spans a total of 890 metabolites, 1175 reactions and 917 metabolic genes, forming an extensive knowledge base for P. thermoglucosidasius NCIMB 11955 metabolism. The model accurately predicts aerobic utilization of 22 carbon sources, and the predictive quality of internal fluxes was validated with previously published 13C-fluxomics data. In an application case, p-thermo was used to facilitate more in-depth analysis of reported metabolic engineering efforts, giving additional insight into fermentative metabolism. Finally, p-thermo was used to resolve a previously uncharacterised bottleneck in anaerobic metabolism, by identifying the minimal required supplemented nutrients (thiamin, biotin and iron(III)) needed to sustain anaerobic growth. This highlights the usefulness of p-thermo for guiding the generation of experimental hypotheses and for facilitating data-driven metabolic engineering, expanding the use of P. thermoglucosidasius as a high yield production platform.
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Affiliation(s)
- Viviënne Mol
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Martyn Bennett
- The Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom; The Centre for Sustainable Chemical Technologies (CSCT), University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom
| | - Benjamín J Sánchez
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark; Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Beata K Lisowska
- The Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom
| | - Markus J Herrgård
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark; BioInnovation Institute, Copenhagen N, Denmark
| | - Alex Toftgaard Nielsen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark.
| | - David J Leak
- The Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom; The Centre for Sustainable Chemical Technologies (CSCT), University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom.
| | - Nikolaus Sonnenschein
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark.
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Han S, Kim Y, Karanjikar M, San KY, Bennett GN. Genetic sensor-regulators functional in Clostridia. J Ind Microbiol Biotechnol 2020; 47:609-620. [DOI: 10.1007/s10295-020-02303-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/18/2020] [Indexed: 11/30/2022]
Abstract
Abstract
This study addressed the functionality of genetic circuits carrying natural regulatory elements of Clostridium acetobutylicum ATCC 824 in the presence of the respective inducer molecules. Specifically, promoters and their regulators involved in diverse carbon source utilization were characterized using mCherryOpt or beta-galactosidase as a reporter. Consequently, most of the genetic circuits tested in this study were functional in Clostridium acetobutylicum ATCC 824 in the presence of an inducer, leading to the expression of reporter proteins. These genetic sensor-regulators were found to be transferable to another Clostridium species, such as Clostridium beijerinckii NCIMB 8052. The gradual expression of reporter protein was observed as a function of the carbohydrates of interest. A xylose-inducible promoter allows a titratable and robust expression of a reporter protein with stringency and efficacy. This xylose-inducible circuit was seen to enable induction of the expression of reporter proteins in the presence of actual sugar mixtures incorporated in woody hydrolysate wherein glucose and xylose are present as predominant carbon sources.
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Affiliation(s)
- SongI Han
- grid.21940.3e 0000 0004 1936 8278 Department of Bioengineering Rice University 77005 Houston TX USA
| | - Younghwan Kim
- grid.427405.0 Technology Holding LLC 84119 West Valley City UT USA
| | | | - Ka-Yiu San
- grid.21940.3e 0000 0004 1936 8278 Department of Bioengineering Rice University 77005 Houston TX USA
- grid.21940.3e 0000 0004 1936 8278 Department of Chemical and Biomolecular Engineering Rice University 77005 Houston TX USA
| | - George N Bennett
- grid.21940.3e 0000 0004 1936 8278 Department of Chemical and Biomolecular Engineering Rice University 77005 Houston TX USA
- grid.21940.3e 0000 0004 1936 8278 Department of BioSciences Rice University 77005 Houston TX USA
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Irla M, Drejer EB, Brautaset T, Hakvåg S. Establishment of a functional system for recombinant production of secreted proteins at 50 °C in the thermophilic Bacillus methanolicus. Microb Cell Fact 2020; 19:151. [PMID: 32723337 PMCID: PMC7389648 DOI: 10.1186/s12934-020-01409-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 07/20/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND The suitability of bacteria as microbial cell factories is dependent on several factors such as price of feedstock, product range, production yield and ease of downstream processing. The facultative methylotroph Bacillus methanolicus is gaining interest as a thermophilic cell factory for production of value-added products from methanol. The aim of this study was to expand the capabilities of B. methanolicus as a microbial cell factory by establishing a system for secretion of recombinant proteins. RESULTS Native and heterologous signal peptides were tested for secretion of α-amylases and proteases, and we have established the use of the thermostable superfolder green fluorescent protein (sfGFP) as a valuable reporter protein in B. methanolicus. We demonstrated functional production and secretion of recombinant proteases, α-amylases and sfGFP in B. methanolicus MGA3 at 50 °C and showed that the choice of signal peptide for optimal secretion efficiency varies between proteins. In addition, we showed that heterologous production and secretion of α-amylase from Geobacillus stearothermophilus enables B. methanolicus to grow in minimal medium with starch as the sole carbon source. An in silico signal peptide library consisting of 169 predicted peptides from B. methanolicus was generated and will be useful for future studies, but was not experimentally investigated any further here. CONCLUSION A functional system for recombinant production of secreted proteins at 50 °C has been established in the thermophilic B. methanolicus. In addition, an in silico signal peptide library has been generated, that together with the tools and knowledge presented in this work will be useful for further development of B. methanolicus as a host for recombinant protein production and secretion at 50 °C.
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Affiliation(s)
- Marta Irla
- Department of Biotechnology and Food Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Eivind B Drejer
- Department of Biotechnology and Food Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Trygve Brautaset
- Department of Biotechnology and Food Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Sigrid Hakvåg
- Department of Biotechnology and Food Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
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Kurashiki R, Mizuno T, Murata K, Ohshiro T, Suzuki H. A plasmid vector that directs hyperproduction of recombinant proteins in the thermophiles Geobacillus species. Extremophiles 2019; 24:147-156. [PMID: 31701242 DOI: 10.1007/s00792-019-01142-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/23/2019] [Indexed: 11/24/2022]
Abstract
Geobacillus spp. are moderate thermophiles that have great potential for use in diverse applications. For effective utilization of the species, genetic tools have been extensively studied; however, an overexpression vector remains to be developed. Here we constructed a plasmid vector that can shuttle between Escherichia coli and Geobacillus spp., and which contained a maltose-inducible promoter from Geobacillus kaustophilus HTA426. Although the vector (termed pGKE119) was originally designed for basal gene expression, it surprisingly directed robust protein production in G. kaustophilus. Protein production essentially occurred in an auto-inducible manner without maltose; however, some proteins were produced more efficiently in the presence of maltose. Although the productivity was affected by culture conditions, three proteins were successfully produced with abundance ratios of 12-27% (on a total protein basis) and yields of 77-170 mg (per L culture). pGKE119 directed substantial protein production even in Geobacillus subterraneus, Geobacillus thermoglucosidasius, and Geobacillus thermoleovorans. This suggests that pGKE119 can use a range of Geobacillus spp. as hosts and widely expand their genetic toolbox. Because Geobacillus spp. are highly proliferative bacteria that are distinct from organisms used as protein production hosts, pGKE119 may also provide a novel platform for hyperproduction of recombinant proteins.
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Affiliation(s)
- Ryota Kurashiki
- Department of Engineering, Graduate School of Sustainability Science, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan
| | - Tatsuki Mizuno
- Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan
| | - Kurumi Murata
- Faculty of Engineering, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan
| | - Takashi Ohshiro
- Faculty of Engineering, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan.,Center for Research on Green Sustainable Chemistry, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan
| | - Hirokazu Suzuki
- Faculty of Engineering, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan. .,Center for Research on Green Sustainable Chemistry, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan.
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11
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Nora LC, Westmann CA, Guazzaroni ME, Siddaiah C, Gupta VK, Silva-Rocha R. Recent advances in plasmid-based tools for establishing novel microbial chassis. Biotechnol Adv 2019; 37:107433. [PMID: 31437573 DOI: 10.1016/j.biotechadv.2019.107433] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 07/11/2019] [Accepted: 08/16/2019] [Indexed: 12/28/2022]
Abstract
A key challenge for domesticating alternative cultivable microorganisms with biotechnological potential lies in the development of innovative technologies. Within this framework, a myriad of genetic tools has flourished, allowing the design and manipulation of complex synthetic circuits and genomes to become the general rule in many laboratories rather than the exception. More recently, with the development of novel technologies such as DNA automated synthesis/sequencing and powerful computational tools, molecular biology has entered the synthetic biology era. In the beginning, most of these technologies were established in traditional microbial models (known as chassis in the synthetic biology framework) such as Escherichia coli and Saccharomyces cerevisiae, enabling fast advances in the field and the validation of fundamental proofs of concept. However, it soon became clear that these organisms, although extremely useful for prototyping many genetic tools, were not ideal for a wide range of biotechnological tasks due to intrinsic limitations in their molecular/physiological properties. Over the last decade, researchers have been facing the great challenge of shifting from these model systems to non-conventional chassis with endogenous capacities for dealing with specific tasks. The key to address these issues includes the generation of narrow and broad host plasmid-based molecular tools and the development of novel methods for engineering genomes through homologous recombination systems, CRISPR/Cas9 and other alternative methods. Here, we address the most recent advances in plasmid-based tools for the construction of novel cell factories, including a guide for helping with "build-your-own" microbial host.
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Affiliation(s)
- Luísa Czamanski Nora
- Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Cauã Antunes Westmann
- Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - María-Eugenia Guazzaroni
- Faculty of Philosophy, Science and Letters of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | | | - Vijai Kumar Gupta
- ERA Chair of Green Chemistry, Department of Chemistry and Biotechnology, School of Science, Tallinn University of Technology, 12618 Tallinn, Estonia
| | - Rafael Silva-Rocha
- Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil.
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Singleton C, Gilman J, Rollit J, Zhang K, Parker DA, Love J. A design of experiments approach for the rapid formulation of a chemically defined medium for metabolic profiling of industrially important microbes. PLoS One 2019; 14:e0218208. [PMID: 31188885 PMCID: PMC6561596 DOI: 10.1371/journal.pone.0218208] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 05/28/2019] [Indexed: 12/30/2022] Open
Abstract
Geobacillus thermoglucosidans DSM2542 is an industrially important microbe, however the complex nutritional requirements of Geobacilli confound metabolic engineering efforts. Previous studies have utilised semi-defined media recipes that contain complex, undefined, biologically derived nutrients which have unknown ingredients that cannot be quantified during metabolic profiling. This study used design of experiments to investigate how individual nutrients and interactions between these nutrients contribute to growth. A mathematically derived defined medium has been formulated that has been shown to robustly support growth of G. thermoglucosidans in two different environmental conditions (96-well plate and shake flask) and with a variety of lignocellulose-based carbohydrates. This enabled the catabolism of industrially relevant carbohydrates to be investigated.
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Affiliation(s)
- Chloe Singleton
- The Exeter Microbial Biofuels Group, College of Life and Environmental Sciences, The University of Exeter, Exeter, Devon, United Kingdom
| | - James Gilman
- The Exeter Microbial Biofuels Group, College of Life and Environmental Sciences, The University of Exeter, Exeter, Devon, United Kingdom
| | - Jessica Rollit
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Kun Zhang
- Shell Technology Centre, Houston, Texas, United States of America
| | - David A. Parker
- The Exeter Microbial Biofuels Group, College of Life and Environmental Sciences, The University of Exeter, Exeter, Devon, United Kingdom
- Shell Technology Centre, Houston, Texas, United States of America
| | - John Love
- The Exeter Microbial Biofuels Group, College of Life and Environmental Sciences, The University of Exeter, Exeter, Devon, United Kingdom
- * E-mail:
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13
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Gilman J, Singleton C, Tennant RK, James P, Howard TP, Lux T, Parker DA, Love J. Rapid, Heuristic Discovery and Design of Promoter Collections in Non-Model Microbes for Industrial Applications. ACS Synth Biol 2019; 8:1175-1186. [PMID: 30995831 DOI: 10.1021/acssynbio.9b00061] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Well-characterized promoter collections for synthetic biology applications are not always available in industrially relevant hosts. We developed a broadly applicable method for promoter identification in atypical microbial hosts that requires no a priori understanding of cis-regulatory element structure. This novel approach combines bioinformatic filtering with rapid empirical characterization to expand the promoter toolkit and uses machine learning to improve the understanding of the relationship between DNA sequence and function. Here, we apply the method in Geobacillus thermoglucosidasius, a thermophilic organism with high potential as a synthetic biology chassis for industrial applications. Bioinformatic screening of G. kaustophilus, G. stearothermophilus, G. thermodenitrificans, and G. thermoglucosidasius resulted in the identification of 636 100 bp putative promoters, encompassing the genome-wide design space and lacking known transcription factor binding sites. Eighty of these sequences were characterized in vivo, and activities covered a 2-log range of predictable expression levels. Seven sequences were shown to function consistently regardless of the downstream coding sequence. Partition modeling identified sequence positions upstream of the canonical -35 and -10 consensus motifs that were predicted to strongly influence regulatory activity in Geobacillus, and artificial neural network and partial least squares regression models were derived to assess if there were a simple, forward, quantitative method for in silico prediction of promoter function. However, the models were insufficiently general to predict pre hoc promoter activity in vivo, most probably as a result of the relatively small size of the training data set compared to the size of the modeled design space.
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Affiliation(s)
- James Gilman
- The BioEconomy Centre, Biosciences, College of Life and Environmental Sciences, Stocker Road, University of Exeter, Exeter EX4 4QD, U.K
| | - Chloe Singleton
- The BioEconomy Centre, Biosciences, College of Life and Environmental Sciences, Stocker Road, University of Exeter, Exeter EX4 4QD, U.K
| | - Richard K. Tennant
- The BioEconomy Centre, Biosciences, College of Life and Environmental Sciences, Stocker Road, University of Exeter, Exeter EX4 4QD, U.K
| | - Paul James
- The BioEconomy Centre, Biosciences, College of Life and Environmental Sciences, Stocker Road, University of Exeter, Exeter EX4 4QD, U.K
| | - Thomas P. Howard
- School of Natural and Environmental Sciences, Newcastle University, Devonshire Building, Newcastle-upon-Tyne NE1 7RU, U.K
| | - Thomas Lux
- Plant Genome and Systems Biology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Munich 85764, Germany
| | - David A. Parker
- Biodomain, Shell Technology Center Houston, 3333 Highway 6 South, Houston, Texas 77082-3101, United States
| | - John Love
- The BioEconomy Centre, Biosciences, College of Life and Environmental Sciences, Stocker Road, University of Exeter, Exeter EX4 4QD, U.K
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14
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Functional Genetic Elements for Controlling Gene Expression in Cupriavidus necator H16. Appl Environ Microbiol 2018; 84:AEM.00878-18. [PMID: 30030234 PMCID: PMC6146998 DOI: 10.1128/aem.00878-18] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 07/12/2018] [Indexed: 12/12/2022] Open
Abstract
A robust and predictable control of gene expression plays an important role in synthetic biology and biotechnology applications. Development and quantitative evaluation of functional genetic elements, such as constitutive and inducible promoters as well as ribosome binding sites (RBSs), are required. In this study, we designed, built, and tested promoters and RBSs for controlling gene expression in the model lithoautotroph Cupriavidus necator H16. A series of variable-strength, insulated, constitutive promoters exhibiting predictable activity within a >700-fold dynamic range was compared to the native P phaC , with the majority of promoters displaying up to a 9-fold higher activity. Positively (AraC/P araBAD -l-arabinose and RhaRS/P rhaBAD -l-rhamnose) and negatively (AcuR/P acuRI -acrylate and CymR/P cmt -cumate) regulated inducible systems were evaluated. By supplying different concentrations of inducers, a >1,000-fold range of gene expression levels was achieved. Application of inducible systems for controlling expression of the isoprene synthase gene ispS led to isoprene yields that exhibited a significant correlation to the reporter protein synthesis levels. The impact of designed RBSs and other genetic elements, such as mRNA stem-loop structure and A/U-rich sequence, on gene expression was also evaluated. A second-order polynomial relationship was observed between the RBS activities and isoprene yields. This report presents quantitative data on regulatory genetic elements and expands the genetic toolbox of C. necatorIMPORTANCE This report provides tools for robust and predictable control of gene expression in the model lithoautotroph C. necator H16. To address a current need, we designed, built, and tested promoters and RBSs for controlling gene expression in C. necator H16. To answer a question on how existing and newly developed inducible systems compare, two positively (AraC/P araBAD -l-arabinose and RhaRS/P rhaBAD -l-rhamnose) and two negatively (AcuR/P acuRI -acrylate and CymR/P cmt -cumate) regulated inducible systems were quantitatively evaluated and their induction kinetics analyzed. To establish if gene expression can be further improved, the effect of genetic elements, such as mRNA stem-loop structure and A/U-rich sequence, on gene expression was evaluated. Using isoprene production as an example, the study investigated if and to what extent chemical compound yield correlates to the level of gene expression of product-synthesizing enzyme.
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Drejer EB, Hakvåg S, Irla M, Brautaset T. Genetic Tools and Techniques for Recombinant Expression in Thermophilic Bacillaceae. Microorganisms 2018; 6:microorganisms6020042. [PMID: 29748477 PMCID: PMC6027425 DOI: 10.3390/microorganisms6020042] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/02/2018] [Accepted: 05/03/2018] [Indexed: 01/17/2023] Open
Abstract
Although Escherichia coli and Bacillus subtilis are the most prominent bacterial hosts for recombinant protein production by far, additional species are being explored as alternatives for production of difficult-to-express proteins. In particular, for thermostable proteins, there is a need for hosts able to properly synthesize, fold, and excrete these in high yields, and thermophilic Bacillaceae represent one potentially interesting group of microorganisms for such purposes. A number of thermophilic Bacillaceae including B.methanolicus, B.coagulans, B.smithii, B.licheniformis, Geobacillus thermoglucosidasius, G. kaustophilus, and G. stearothermophilus are investigated concerning physiology, genomics, genetic tools, and technologies, altogether paving the way for their utilization as hosts for recombinant production of thermostable and other difficult-to-express proteins. Moreover, recent successful deployments of CRISPR/Cas9 in several of these species have accelerated the progress in their metabolic engineering, which should increase their attractiveness for future industrial-scale production of proteins. This review describes the biology of thermophilic Bacillaceae and in particular focuses on genetic tools and methods enabling use of these organisms as hosts for recombinant protein production.
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Affiliation(s)
- Eivind B Drejer
- Department of Biotechnology and Food Science, NTNU: Norwegian University of Science and Technology, 7491 Trondheim, Norway.
| | - Sigrid Hakvåg
- Department of Biotechnology and Food Science, NTNU: Norwegian University of Science and Technology, 7491 Trondheim, Norway.
| | - Marta Irla
- Department of Biotechnology and Food Science, NTNU: Norwegian University of Science and Technology, 7491 Trondheim, Norway.
| | - Trygve Brautaset
- Department of Biotechnology and Food Science, NTNU: Norwegian University of Science and Technology, 7491 Trondheim, Norway.
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Frenzel E, Legebeke J, van Stralen A, van Kranenburg R, Kuipers OP. In vivo selection of sfGFP variants with improved and reliable functionality in industrially important thermophilic bacteria. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:8. [PMID: 29371884 PMCID: PMC5771013 DOI: 10.1186/s13068-017-1008-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 12/29/2017] [Indexed: 05/03/2023]
Abstract
BACKGROUND Fluorescent reporter proteins (FP) have become an indispensable tool for the optimization of microbial cell factories and in synthetic biology per se. The applicability of the currently available FPs is, however, constrained by species-dependent performance and misfolding at elevated temperatures. To obtain functional reporters for thermophilic, biotechnologically important bacteria such as Parageobacillus thermoglucosidasius, an in vivo screening approach based on a mutational library of superfolder GFP was applied. RESULTS Flow cytometry-based benchmarking of a set of GFPs, sfGFPs and species-specific codon-optimized variants revealed that none of the proteins was satisfyingly detectable in P. thermoglucosidasius at its optimal growth temperature of 60 °C. An undirected mutagenesis approach coupled to fluorescence-activated cell sorting allowed the isolation of sfGFP variants that were extremely well expressed in the chassis background at 60 °C. Notably, a few nucleotide substitutions, including silent mutations, significantly improved the functionality and brightness. The best mutant sfGFP(N39D/A179A) showed an 885-fold enhanced mean fluorescence intensity (MFI) at 60 °C and is the most reliable reporter protein with respect to cell-to-cell variation and signal intensity reported so far. The in vitro spectral and thermostability properties were unaltered as compared to the parental sfGFP protein, strongly indicating that the combination of the amino acid exchange and an altered translation or folding speed, or protection from degradation, contribute to the strongly improved in vivo performance. Furthermore, sfGFP(N39D/A179A) and the newly developed cyan and yellow derivatives were successfully used for labeling several industrially relevant thermophilic bacilli, thus proving their broad applicability. CONCLUSIONS This study illustrates the power of in vivo isolation of thermostable proteins to obtain reporters for highly efficient fluorescence labeling. Successful expression in a variety of thermophilic bacteria proved that the novel FPs are highly suitable for imaging and flow cytometry-based studies. This enables a reliable cell tracking and single-cell-based real-time monitoring of biological processes that are of industrial and biotechnological interest.
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Affiliation(s)
- Elrike Frenzel
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Jelmer Legebeke
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Atze van Stralen
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Richard van Kranenburg
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
- Corbion, Arkselsedijk 46, 4206 AC Gorinchem, The Netherlands
| | - Oscar P. Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
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Yan Q, Fong SS. Challenges and Advances for Genetic Engineering of Non-model Bacteria and Uses in Consolidated Bioprocessing. Front Microbiol 2017; 8:2060. [PMID: 29123506 PMCID: PMC5662904 DOI: 10.3389/fmicb.2017.02060] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/09/2017] [Indexed: 12/26/2022] Open
Abstract
Metabolic diversity in microorganisms can provide the basis for creating novel biochemical products. However, most metabolic engineering projects utilize a handful of established model organisms and thus, a challenge for harnessing the potential of novel microbial functions is the ability to either heterologously express novel genes or directly utilize non-model organisms. Genetic manipulation of non-model microorganisms is still challenging due to organism-specific nuances that hinder universal molecular genetic tools and translatable knowledge of intracellular biochemical pathways and regulatory mechanisms. However, in the past several years, unprecedented progress has been made in synthetic biology, molecular genetics tools development, applications of omics data techniques, and computational tools that can aid in developing non-model hosts in a systematic manner. In this review, we focus on concerns and approaches related to working with non-model microorganisms including developing molecular genetics tools such as shuttle vectors, selectable markers, and expression systems. In addition, we will discuss: (1) current techniques in controlling gene expression (transcriptional/translational level), (2) advances in site-specific genome engineering tools [homologous recombination (HR) and clustered regularly interspaced short palindromic repeats (CRISPR)], and (3) advances in genome-scale metabolic models (GSMMs) in guiding design of non-model species. Application of these principles to metabolic engineering strategies for consolidated bioprocessing (CBP) will be discussed along with some brief comments on foreseeable future prospects.
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Affiliation(s)
- Qiang Yan
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA, United States
| | - Stephen S. Fong
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA, United States
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, VA, United States
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Jensen TØ, Pogrebnyakov I, Falkenberg KB, Redl S, Nielsen AT. Application of the thermostable β-galactosidase, BgaB, from Geobacillus stearothermophilus as a versatile reporter under anaerobic and aerobic conditions. AMB Express 2017; 7:169. [PMID: 28875485 PMCID: PMC5585113 DOI: 10.1186/s13568-017-0469-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 08/29/2017] [Indexed: 11/10/2022] Open
Abstract
Use of thermophilic organisms has a range of advantages, but the significant lack of engineering tools limits their applications. Here we show that β-galactosidase from Geobacillus stearothermophilus (BgaB) can be applicable in a range of conditions, including different temperatures and oxygen concentrations. This protein functions both as a marker, promoting colony color development in the presence of a lactose analogue S-gal, and as a reporter enabling quantitative measurement by a simple colorimetric assay. Optimal performance was observed at 70 °C and pH 6.4. The gene was introduced into G. thermoglucosidans. The combination of BgaB expressed from promoters of varying strength with S-gal produced distinct black colonies in aerobic and anaerobic conditions at temperatures ranging from 37 to 60 °C. It showed an important advantage over the conventional β-galactosidase (LacZ) and substrate X-gal, which were inactive at high temperature and under anaerobic conditions. To demonstrate the versatility of the reporter, a promoter library was constructed by randomizing sequences around −35 and −10 regions in a wild type groES promoter from Geobacillus sp. GHH01. The library contained 28 promoter variants and encompassed fivefold variation. The experimental pipeline allowed construction and measurement of expression levels of the library in just 4 days. This β-galactosidase provides a promising tool for engineering of aerobic, anaerobic, and thermophilic production organisms such as Geobacillus species.
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