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Valencia-Marin MF, Chávez-Avila S, Guzmán-Guzmán P, Orozco-Mosqueda MDC, de Los Santos-Villalobos S, Glick BR, Santoyo G. Survival strategies of Bacillus spp. in saline soils: Key factors to promote plant growth and health. Biotechnol Adv 2024; 70:108303. [PMID: 38128850 DOI: 10.1016/j.biotechadv.2023.108303] [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: 08/16/2023] [Revised: 11/16/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023]
Abstract
Soil salinity is one of the most important abiotic factors that affects agricultural production worldwide. Because of saline stress, plants face physiological changes that have negative impacts on the various stages of their development, so the employment of plant growth-promoting bacteria (PGPB) is one effective means to reduce such toxic effects. Bacteria of the Bacillus genus are excellent PGPB and have been extensively studied, but what traits makes them so extraordinary to adapt and survive under harsh situations? In this work we review the Bacillus' innate abilities to survive in saline stressful soils, such as the production osmoprotectant compounds, antioxidant enzymes, exopolysaccharides, and the modification of their membrane lipids. Other survival abilities are also discussed, such as sporulation or a reduced growth state under the scope of a functional interaction in the rhizosphere. Thus, the most recent evidence shows that these saline adaptive activities are important in plant-associated bacteria to potentially protect, direct and indirect plant growth-stimulating activities. Additionally, recent advances on the mechanisms used by Bacillus spp. to improve the growth of plants under saline stress are addressed, including genomic and transcriptomic explorations. Finally, characterization and selection of Bacillus strains with efficient survival strategies are key factors in ameliorating saline problems in agricultural production.
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Affiliation(s)
- María F Valencia-Marin
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich. 58030, Mexico
| | - Salvador Chávez-Avila
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich. 58030, Mexico
| | - Paulina Guzmán-Guzmán
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich. 58030, Mexico
| | - Ma Del Carmen Orozco-Mosqueda
- Departamento de Ingeniería Bioquímica y Ambiental, Tecnológico Nacional de México en Celaya, 38010 Celaya, Gto, Mexico
| | | | - Bernard R Glick
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Gustavo Santoyo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich. 58030, Mexico.
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Alba-Posse EJ, Bruque CD, Gándola Y, Gasulla J, Nadra AD. From in-silico screening to in-vitro evaluation: Enhancing the detection of Microcystins with engineered PP1 mutant variants. J Struct Biol 2023; 215:108043. [PMID: 37935286 DOI: 10.1016/j.jsb.2023.108043] [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: 07/15/2023] [Revised: 10/20/2023] [Accepted: 11/04/2023] [Indexed: 11/09/2023]
Abstract
Cyanotoxins produced during harmful algal blooms (CyanoHABs) have become a worldwide issue of concern. Microcystins (MC) are the most ubiquitous group of cyanotoxins and have known carcinogenic and hepatotoxic effects. The protein phosphatase inhibition assays (PPIAs), based on the inhibition of Protein Phosphatase 1/2A (PP1/PP2A) by MC, are one of the most cost-effective options for detecting MC. In this work, we aimed to design in-silico and evaluate in-vitro mutant variants of the PP1 protein, in order to enhance their capabilities as a MC biosensor. To this end, we performed an in-silico active site-saturated mutagenesis screening, followed by stability and docking affinity calculation with the MCLR cyanotoxin. Candidates with improved both affinity and stability were further tested in a fully flexible active-site docking. The best-scored mutations (19) were individually analysed regarding their locations and interactions. Four of them (p.D197F; p.Q249Y; p.S129W; p.D220Q) were selected for in-vitro expression and evaluation. Mutant p.D197F, exhibited a significant increment in inhibition by MCLR with respect to the WT, while showing a non-significant difference in stability nor activity. This successful PP1 inhibition enhancement suggests the potential of the p.D197F variant for practical MC detection applications.
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Affiliation(s)
- Ezequiel J Alba-Posse
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB Buenos Aires, Argentina
| | - Carlos David Bruque
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB Buenos Aires, Argentina; Unidad de Conocimiento Traslacional Hospitalaria Patagónica, Hospital de Alta Complejidad El Calafate - S.A.M.I.C., Jorge Newbery 453, CP9405 El Calafate, Santa Cruz, Argentina
| | - Yamila Gándola
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA Buenos Aires, Argentina
| | - Javier Gasulla
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB Buenos Aires, Argentina.
| | - Alejandro D Nadra
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB Buenos Aires, Argentina.
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3
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Sun X, Yang J, Fu X, Zhao X, Zhen J, Song H, Xu J, Zheng H, Bai W. Trehalose Production Using Three Extracellular Enzymes Produced via One-Step Fermentation of an Engineered Bacillus subtilis Strain. Bioengineering (Basel) 2023; 10:977. [PMID: 37627862 PMCID: PMC10451709 DOI: 10.3390/bioengineering10080977] [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: 07/12/2023] [Revised: 08/04/2023] [Accepted: 08/14/2023] [Indexed: 08/27/2023] Open
Abstract
At present, the double-enzyme catalyzed method using maltooligosyltrehalose synthase (MTSase) and maltooligosyltrehalose trehalohydrolase (MTHase) is the mainstream technology for industrial trehalose production. However, MTSase and MTHase are prepared mainly using the heterologous expression in the engineered Escherichia coli strains so far. In this study, we first proved that the addition of 3 U/g neutral pullulanase PulA could enhance the trehalose conversion rate by 2.46 times in the double-enzyme catalyzed system. Then, a CBM68 domain was used to successfully assist the secretory expression of MTSase and MTHase from Arthrobacter ramosus S34 in Bacillus subtilis SCK6. At the basis, an engineered strain B. subtilis PSH02 (amyE::pulA/pHT43-C68-ARS/pMC68-ARH), which co-expressed MTSase, MTHase, and PulA, was constructed. After the 24 h fermentation of B. subtilis PSH02, the optimum ratio of the extracellular multi-enzymes was obtained to make the highest trehalose conversion rate of 80% from 100 g/L maltodextrin. The high passage stability and multi-enzyme preservation stability made B. subtilis PSH02 an excellent industrial production strain. Moreover, trehalose production using these extracellular enzymes produced via the one-step fermentation of B. subtilis PSH02 would greatly simplify the procedure for multi-enzyme preparation and be expected to reduce production costs.
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Affiliation(s)
- Xi Sun
- College of Biological Engineering, Tianjin Agricultural University, Tianjin 300384, China; (X.S.); (J.Y.)
| | - Jun Yang
- College of Biological Engineering, Tianjin Agricultural University, Tianjin 300384, China; (X.S.); (J.Y.)
| | - Xiaoping Fu
- National Center of Technology Innovation for Synthetic Biology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; (X.F.); (H.S.); (J.X.)
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Xingya Zhao
- Industrial Enzymes National Engineering Research Center, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; (X.Z.); (J.Z.)
- Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Jie Zhen
- Industrial Enzymes National Engineering Research Center, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; (X.Z.); (J.Z.)
- Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Hui Song
- National Center of Technology Innovation for Synthetic Biology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; (X.F.); (H.S.); (J.X.)
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- Industrial Enzymes National Engineering Research Center, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; (X.Z.); (J.Z.)
- Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Jianyong Xu
- National Center of Technology Innovation for Synthetic Biology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; (X.F.); (H.S.); (J.X.)
- Industrial Enzymes National Engineering Research Center, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; (X.Z.); (J.Z.)
- Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Hongchen Zheng
- National Center of Technology Innovation for Synthetic Biology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; (X.F.); (H.S.); (J.X.)
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- Industrial Enzymes National Engineering Research Center, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; (X.Z.); (J.Z.)
- Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Wenqin Bai
- National Center of Technology Innovation for Synthetic Biology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; (X.F.); (H.S.); (J.X.)
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
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Lenz P, Hilgers F, Burmeister A, Zimmermann L, Volkenborn K, Grünberger A, Kohlheyer D, Drepper T, Jaeger KE, Knapp A. The iSplit GFP assay detects intracellular recombinant proteins in Bacillus subtilis. Microb Cell Fact 2021; 20:174. [PMID: 34488765 PMCID: PMC8419962 DOI: 10.1186/s12934-021-01663-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 08/19/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Bacillus subtilis is one of the most important microorganisms for recombinant protein production. It possesses the GRAS (generally recognized as safe) status and a potent protein secretion capacity. Secretory protein production greatly facilitates downstream processing and thus significantly reduces costs. However, not all heterologous proteins are secreted and intracellular production poses difficulties for quantification. To tackle this problem, we have established a so-called intracellular split GFP (iSplit GFP) assay in B. subtilis as a tool for the in vivo protein detection during expression in batch cultures and at a single-cell level. For the iSplit GFP assay, the eleventh β-sheet of sfGFP is fused to a target protein and can complement a detector protein consisting of the respective truncated sfGFP (GFP1-10) to form fluorescent holo-GFP. RESULTS As proof of concept, the GFP11-tag was fused C-terminally to the E. coli β-glucuronidase GUS, resulting in fusion protein GUS11. Variable GUS and GUS11 production levels in B. subtilis were achieved by varying the ribosome binding site via spacers of increasing lengths (4-12 nucleotides) for the GUS-encoding gene. Differences in intracellular enzyme accumulation were determined by measuring the GUS11 enzymatic activity and subsequently by adding the detector protein to respective cell extracts. Moreover, the detector protein was co-produced with the GUS11 using a two-plasmid system, which enabled the in vivo detection and online monitoring of glucuronidase production. Using this system in combination with flow cytometry and microfluidics, we were able to monitor protein production at a single-cell level thus yielding information about intracellular protein distribution and culture heterogeneity. CONCLUSION Our results demonstrate that the iSplit GFP assay is suitable for the detection, quantification and online monitoring of recombinant protein production in B. subtilis during cultivation as well as for analyzing production heterogeneity and intracellular localization at a single-cell level.
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Affiliation(s)
- Patrick Lenz
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Fabienne Hilgers
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Alina Burmeister
- Institute of Bio- and Geoscience, IBG-1: Biotechnology: Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
- Multiscale Bioengineering, Bielefeld University, 33615, Bielefeld, Germany
| | - Leonie Zimmermann
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Kristina Volkenborn
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Alexander Grünberger
- Institute of Bio- and Geoscience, IBG-1: Biotechnology: Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
- Multiscale Bioengineering, Bielefeld University, 33615, Bielefeld, Germany
| | - Dietrich Kohlheyer
- Institute of Bio- and Geoscience, IBG-1: Biotechnology: Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
- RWTH Aachen University, Microscale Bioengineering (AVT.MSB), 52074, Aachen, Germany
| | - Thomas Drepper
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Karl-Erich Jaeger
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, 52425, Jülich, Germany
- Institute of Bio- and Geoscience, IBG-1: Biotechnology: Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Andreas Knapp
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, 52425, Jülich, Germany.
- Castrol Germany GmbH, 41179, Mönchengladbach, Germany.
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Yang H, Qu J, Zou W, Shen W, Chen X. An overview and future prospects of recombinant protein production in Bacillus subtilis. Appl Microbiol Biotechnol 2021; 105:6607-6626. [PMID: 34468804 DOI: 10.1007/s00253-021-11533-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/12/2021] [Accepted: 08/15/2021] [Indexed: 12/27/2022]
Abstract
Bacillus subtilis is a well-characterized Gram-positive bacterium and a valuable host for recombinant protein production because of its efficient secretion ability, high yield, and non-toxicity. Here, we comprehensively review the recent studies on recombinant protein production in B. subtilis to update and supplement other previous reviews. We have focused on several aspects, including optimization of B. subtilis strains, enhancement and regulation of expression, improvement of secretion level, surface display of proteins, and fermentation optimization. Among them, optimization of B. subtilis strains mainly involves undirected chemical/physical mutagenesis and selection and genetic manipulation; enhancement and regulation of expression comprises autonomous plasmid and integrated expression, promoter regulation and engineering, and fine-tuning gene expression based on proteases and molecular chaperones; improvement of secretion level predominantly involves secretion pathway and signal peptide screening and optimization; surface display of proteins includes surface display of proteins on spores or vegetative cells; and fermentation optimization incorporates medium optimization, process condition optimization, and feeding strategy optimization. Furthermore, we propose some novel methods and future challenges for recombinant protein production in B. subtilis.Key points• A comprehensive review on recombinant protein production in Bacillus subtilis.• Novel techniques facilitate recombinant protein expression and secretion.• Surface display of proteins has significant potential for different applications.
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Affiliation(s)
- Haiquan Yang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.
| | - Jinfeng Qu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Wei Zou
- College of Bioengineering, Sichuan University of Science & Engineering, Yibin, 644000, Sichuan, China
| | - Wei Shen
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Xianzhong Chen
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.
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Souza CCD, Guimarães JM, Pereira SDS, Mariúba LAM. The multifunctionality of expression systems in Bacillus subtilis: Emerging devices for the production of recombinant proteins. Exp Biol Med (Maywood) 2021; 246:2443-2453. [PMID: 34424091 PMCID: PMC8649419 DOI: 10.1177/15353702211030189] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Bacillus subtilis is a successful host for producing recombinant proteins. Its GRAS (generally recognized as safe) status and its remarkable innate ability to absorb and incorporate exogenous DNA into its genome make this organism an ideal platform for the heterologous expression of bioactive substances. The factors that corroborate its value can be attributed to the scientific knowledge obtained from decades of study regarding its biology that has fostered the development of several genetic engineering strategies, such as the use of different plasmids, engineering of constitutive or double promoters, chemical inducers, systems of self-inducing expression with or without a secretion system that uses a signal peptide, and so on. Tools that enrich the technological arsenal of this expression platform improve the efficiency and reduce the costs of production of proteins of biotechnological importance. Therefore, this review aims to highlight the major advances involving recombinant expression systems developed in B. subtilis, thus sustaining the generation of knowledge and its application in future research. It was verified that this bacterium is a model in constant demand and studies of the expression of recombinant proteins on a large scale are increasing in number. As such, it represents a powerful bacterial host for academic research and industrial purposes.
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Affiliation(s)
- Caio Coutinho de Souza
- Programa de Pós-Graduação em Biotecnologia da Universidade Federal do Amazonas - UFAM, Manaus, AM 69067-005, Brazil
| | - Jander Matos Guimarães
- Centro Multiusuário de Análise de Fenômenos Biomédicos (CMABio) da Universidade do Estado do Amazonas (UEA), Manaus, AM 69065-00, Brazil
| | - Soraya Dos Santos Pereira
- Fundação Oswaldo Cruz (FIOCRUZ) Unidade de Rondônia, Porto Velho-RO 76812-245, Brazil.,Programa de Pós-Graduação em Biologia Experimental, Fundação Universidade Federal de Rondônia-PGBIOEXP/UNIR, Porto Velho-RO 76801-974, Brazil.,Instituto Leônidas e Maria Deane (ILMD), Fundação Oswaldo Cruz (FIOCRUZ), Manaus, AM 69057-070, Brazil
| | - Luis André Morais Mariúba
- Programa de Pós-Graduação em Biotecnologia da Universidade Federal do Amazonas - UFAM, Manaus, AM 69067-005, Brazil.,Programa de Pós-Graduação em Biologia Celular e Molecular, Instituto Oswaldo Cruz, IOC, Rio de Janeiro 21040-360, Brazil.,Instituto Leônidas e Maria Deane (ILMD), Fundação Oswaldo Cruz (FIOCRUZ), Manaus, AM 69057-070, Brazil.,Programa de Pós-Graduação em Imunologia Básica e Aplicada, Instituto de Ciências Biológicas, Universidade Federal do Amazonas (UFAM), Manaus, AM 69067-00, Brazil
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Research progress and the biotechnological applications of multienzyme complex. Appl Microbiol Biotechnol 2021; 105:1759-1777. [PMID: 33564922 DOI: 10.1007/s00253-021-11121-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 01/07/2021] [Accepted: 01/16/2021] [Indexed: 11/26/2022]
Abstract
The multienzyme complex system has become a research focus in synthetic biology due to its highly efficient overall catalytic ability and has been applied to various fields. Multienzyme complexes are formed by cascading complexes, which are multiple functionally related enzymes that continuously and efficiently catalyze the production of substrates. Compared with current mainstream microbial cell catalytic systems, in vitro multienzyme molecular machines have many advantages, such as fewer side reactions, a high product yield, a fast reaction speed, easy product separation, a tolerable toxic environment, and robust system operability, showing increasing competitiveness in the field of biomanufacturing. In this review, the research progress of multienzyme complexes in nature and multienzyme cascades in vivo or in vitro will be introduced, and the discovered enzyme cascades concerning scaffolding proteins will also be discussed. This review is expected to provide a more theoretical basis for the modification of multienzyme complexes and broaden their application in the field of synthetic biology. KEY POINTS: • The cascade reactions of some natural multienzyme complexes are reviewed. • The main approaches of constructing artificial multienzyme complexes are summarized. • The structure and application of cellulosomes are discussed and prospected.
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Integrative expression vectors with P grac promoters for inducer-free overproduction of recombinant proteins in Bacillus subtilis. BIOTECHNOLOGY REPORTS (AMSTERDAM, NETHERLANDS) 2020; 28:e00540. [PMID: 33163371 PMCID: PMC7599426 DOI: 10.1016/j.btre.2020.e00540] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 09/28/2020] [Accepted: 10/08/2020] [Indexed: 11/27/2022]
Abstract
The new inducer-free integrative expression vectors could repress the reporter gene expression in the E. coli cloning strain, thereby facilitating the cloning step. The expression vectors carrying IPTG-inducible Pgrac promoters allow the production of the recombinant protein at high levels in B. subtilis in the absence of the inducer. The single-copy expression levels of integrative constructs, Pgrac01-bgaB, Pgrac100-bgaB, Pgrac212-bgaB could reach to % and 8%, 20.9 % and 42 % of total cellular proteins after 12 h incubation, respectively. The double integration of Pgrac212-bgaB into both amyE and lacA loci resulted in BgaB expression up to 53.4 %.
Inducer-free integrative vectors are often used to create B. subtilis strains for industrial purposes, but employing strong promoters to produce high levels of recombinant proteins in B. subtilis results in high leaky expression that can hamper cloning in Escherichia coli. To overcome the problem, we used strong IPTG-inducible Pgrac promoters harboring lac operators to construct inducer-free integrative vectors able to integrate into the B. subtilis genome at either the lacA or the amyE locus, or both and examined their ability to repress the β-galactosidase (bgaB) gene in E. coli and to overexpress BgaB in B. subtilis. The Pgrac01 vectors could repress bgaB expression about 24-fold in E. coli to low background levels. The integrated Pgrac01-bgaB constructs exhibited inducer-free expression and produced 8% of total cellular proteins, only 1.25 or 1.75 times less compared with their cognates as plasmids. The stronger promoters, Pgrac100-bgaB and Pgrac212-bgaB yielded 20.9 % and 42 % of total intracellular proteins after 12 h of incubation, respectively. Incorporation of the Pgrac212-bgaB into both amyE and lacA loci resulted in BgaB expression up to 53.4 %. In conclusion, integrative vectors containing the Pgrac promoter family have great potential for inducer-free overproduction of recombinant proteins in B. subtilis.
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