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Deedwania A, Karmakar S, Kumar V, Shefrin S, Sundar D, Srivastava P. Construction and characterization of a temperature-sensitive pRC4 replicon for Rhodococcus and Gordonia. Gene 2024; 896:147990. [PMID: 37977321 DOI: 10.1016/j.gene.2023.147990] [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: 10/17/2023] [Revised: 11/08/2023] [Accepted: 11/13/2023] [Indexed: 11/19/2023]
Abstract
Temperature-sensitive plasmids are useful for genome engineering and several synthetic biology applications. There are only limited reports on temperature-sensitive plasmids for Rhodococcus and none for Gordonia. Here, we report the construction of a temperature-sensitive pRC4 replicon that is functional in Rhodococcus and Gordonia. The amino acid residues were predicted for the temperature-sensitive phenotype in the pRC4 replicon using in silico methods and molecular simulation of the DNA-binding replication protein with the origin of replication. The amino acid residues were mutated, and the temperature-sensitive phenotype was validated in Gordonia sp. IITR100. Similar results were also observed in Rhodococcus erythropolis, suggesting that the temperature-sensitive phenotype was exhibited across genera.
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Affiliation(s)
- Agrima Deedwania
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi 110 016, India
| | - Shreyoshi Karmakar
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi 110 016, India
| | - Vipul Kumar
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi 110 016, India
| | - Seyad Shefrin
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi 110 016, India
| | - Durai Sundar
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi 110 016, India.
| | - Preeti Srivastava
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi 110 016, India.
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2
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Li X, Zhang Y, Zhan Y, Tian H, Yan B, Cai J. Utilization of a strong promoter combined with the knockout of protease genes to improve the yield of Vip3Aa in Bacillus thuringiensis BMB171. PEST MANAGEMENT SCIENCE 2023; 79:1713-1720. [PMID: 36622044 DOI: 10.1002/ps.7343] [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: 08/12/2022] [Revised: 12/15/2022] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND Vip3Aa is an insecticidal protein secreted by some Bacillus thuringiensis strains during vegetative growth. It has excellent insecticidal activity, its mechanism of action is different from that of Cry protein, and it can delay the development of pest resistance. To date, Vip3Aa has been widely used in genetically modified Bt crops. However, the secretion of Vip3Aa by industrial production strains is usually very low. Moreover, most of the Vip3Aa in the medium is degraded by proteases, limiting its application as a biopesticide. RESULTS We report a novel constitutive strong promoter from B. thuringiensis, Prsi , which directs the abundant expression of vip3Aa in B. thuringiensis BMB171. Furthermore, to reduce the degradation of Vip3Aa caused by proteases, we constructed B. thuringiensis mutants in which different protease genes were knocked out. We found that the degradation of Vip3Aa was greatly inhibited and its yield was significantly improved in a mutant that lacked all three protease genes. CONCLUSION Our results provide a new strategy to enhance the production of Vip3Aa in B. thuringiensis and have reference value for the research and development of novel bioinsecticides. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Xuelian Li
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yanli Zhang
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yunda Zhan
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Hongwei Tian
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Bing Yan
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Jun Cai
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, China
- Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, China
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3
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Wang Y, Liu X, Li Y, Yang Y, Liu C, Linhardt RJ, Zhang F, Bai Z. Enhanced production of recombinant proteins in Corynebacterium glutamicum using a molecular chaperone. J GEN APPL MICROBIOL 2023. [PMID: 36878578 DOI: 10.2323/jgam.2022.10.002] [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: 03/06/2023]
Abstract
Protein synthesis in Corynebacterium glutamicum is critical for applications in biotechnology and medicine. However, the use of C. glutamicum for protein production is limited by its low expression and aggregation. To overcome these limitations, a molecular chaperone plasmid system was developed in this study to improve the efficiency of recombinant protein synthesis in C. glutamicum. The effect of molecular chaperones on target protein synthesis (Single-chain variable fragment, Scfv) under three different promoter strengths was tested. In addition, the plasmid containing the molecular chaperone and target protein was verified for growth stability and plasmid stability. This expression model was further validated using two recombinant proteins, human interferon-beta (Hifn) and hirudin variant III (Rhv3). Finally, the Rhv3 protein was purified, and analysis of Rhv3 activity confirmed that the use of a molecular chaperone led to an improvement in test protein synthesis. Thus, the use of molecular chaperones is believed to will improve recombinant proteins synthesis in C. glutamicum.
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Affiliation(s)
- Yali Wang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University.,National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University
| | - Xiuxia Liu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University.,National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University
| | - Ye Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University.,National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University
| | - Yankun Yang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University.,National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University
| | - Chunli Liu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University.,National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University
| | - Robert J Linhardt
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute
| | - Fuming Zhang
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute
| | - Zhonghu Bai
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University.,National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University
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Hao R, Wang S, Jin X, Yang X, Qi Q, Liang Q. Dynamic and balanced regulation of the thrABC operon gene for efficient synthesis of L-threonine. Front Bioeng Biotechnol 2023; 11:1118948. [PMID: 36937754 PMCID: PMC10018013 DOI: 10.3389/fbioe.2023.1118948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 02/21/2023] [Indexed: 03/06/2023] Open
Abstract
L-threonine is an essential amino acid used widely in food, cosmetics, animal feed and medicine. The thrABC operon plays an important role in regulating the biosynthesis of L-theronine. In this work, we systematically analyzed the effects of separating thrAB and thrC in different proportions on strain growth and L-threonine production in Escherichia coli firstly. The results showed that higher expression of thrC than thrAB enhanced cell growth and L-threonine production; however, L-threonine production decreased when the thrC proportion was too high. The highest L-threonine production was achieved when the expression intensity ratio of thrAB to thrC was 3:5. Secondly, a stationary phase promoter was also used to dynamically regulate the expression of engineered thrABC. This strategy improved cell growth and shortened the fermentation period from 36 h to 24 h. Finally, the acetate metabolic overflow was reduced by deleting the ptsG gene, leading to a further increase in L-threonine production. With these efforts, the final strain P 2.1 -2901ΔptsG reached 40.06 g/L at 60 h fermentation, which was 96.85% higher than the initial control strain TH and the highest reported titer in shake flasks. The maximum L-threonine yield and productivity was obtained in reported fed-batch fermentation, and L-threonine production is close to the highest titer (127.30 g/L). In this work, the expression ratio of genes in the thrABC operon in E. coli was studied systematically, which provided a new approach to improve L-threonine production and its downstream products.
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Moschner C, Wedd C, Bakshi S. The context matrix: Navigating biological complexity for advanced biodesign. Front Bioeng Biotechnol 2022; 10:954707. [PMID: 36082163 PMCID: PMC9445834 DOI: 10.3389/fbioe.2022.954707] [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: 06/07/2022] [Accepted: 06/29/2022] [Indexed: 12/05/2022] Open
Abstract
Synthetic biology offers many solutions in healthcare, production, sensing and agriculture. However, the ability to rationally engineer synthetic biosystems with predictable and robust functionality remains a challenge. A major reason is the complex interplay between the synthetic genetic construct, its host, and the environment. Each of these contexts contains a number of input factors which together can create unpredictable behaviours in the engineered biosystem. It has become apparent that for the accurate assessment of these contextual effects a more holistic approach to design and characterisation is required. In this perspective article, we present the context matrix, a conceptual framework to categorise and explore these contexts and their net effect on the designed synthetic biosystem. We propose the use and community-development of the context matrix as an aid for experimental design that simplifies navigation through the complex design space in synthetic biology.
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Liu YX, Zhuo XZ, Li SY. The Transcription Activator AtxA from Bacillus Anthracis was Employed for Developing a Tight-Control, High-Level, Modulable, and Stationary-Phase Specific Transcription Activity in Escherichia Coli. Synth Biol (Oxf) 2022; 7:ysac014. [PMID: 36046151 PMCID: PMC9424709 DOI: 10.1093/synbio/ysac014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 06/16/2022] [Accepted: 08/16/2022] [Indexed: 11/13/2022] Open
Abstract
The strong transcriptional activity of the virulent gene pagA in Bacillus anthracis has been proven to be anthrax toxin activator (AtxA)-regulated. However, the obscure pagA transcription mechanism hinders practical applications of this strong promoter. In this study, a 509-bp DNA fragment [termed 509sequence, (−508)-(+1) relative to the P2 transcription start site] was cloned upstream of rbs-GFPuv as pTOL02B to elucidate the AtxA-regulated transcription. The 509sequence was dissected into the −10 sequence, −35 sequence, ATrich tract, SLI/SLII and upstream site. In conjunction with the heterologous co-expression of AtxA (under the control of the T7 promoter), the −10 sequence (TATACT) was sufficient for the AtxA-regulated transcription. Integration of pTOL02F + pTOLAtxA as pTOL03F showed that the AtxA-regulated transcription exhibited a strong specific fluorescence intensity/common analytical chemistry term (OD600) of 40 597 ± 446 and an induction/repression ratio of 122. An improved induction/repression ratio of 276 was achieved by cultivating Escherichia coli/pTOL03F in M9 minimal medium. The newly developed promoter system termed PAtxA consists of AtxA, the −10 sequence and Escherichia RNA polymerase. These three elements synergistically and cooperatively formed a previously undiscovered transcription system, which exhibited a tight-control, high-level, modulable and stationary-phase-specific transcription. The PAtxA was used for phaCAB expression for the stationary-phase polyhydroxybutyrate production, and the results showed that a PHB yield, content and titer of 0.20 ± 0.27 g/g-glucose, 68 ± 11% and 1.5 ± 0.4 g/l can be obtained. The positive inducible PAtxA, in contrast to negative inducible, should be a useful tool to diversify the gene information flow in synthetic biology.
Graphical Abstract
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Affiliation(s)
- Ying-Xing Liu
- Department of Chemical Engineering, National Chung Hsing University , Taichung 402, Taiwan
| | - Xiao-Zhen Zhuo
- Department of Chemical Engineering, National Chung Hsing University , Taichung 402, Taiwan
| | - Si-Yu Li
- Department of Chemical Engineering, National Chung Hsing University , Taichung 402, Taiwan
- Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University , Taichung 402, Taiwan
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7
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Jaishankar J, Keshav A, Jayaram B, Chavan S, Srivastava P. Characterization of divergent promoters PmaiA and Phyd from Gordonia: Co-expression and regulation by CRP. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2022; 1865:194843. [PMID: 35840055 DOI: 10.1016/j.bbagrm.2022.194843] [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: 02/21/2022] [Revised: 07/06/2022] [Accepted: 07/07/2022] [Indexed: 06/15/2023]
Abstract
Divergent promoters are often responsible for controlling gene expression of related genes of the same pathway or for coordinating regulation at different time points. There are relatively few reports on characterization of divergent promoters in bacteria. In the present study, microarray profiling was carried out to analyze gene expression during growth of Gordonia sp. IITR100, which led to the identification of 35 % of adjacent gene candidates that are divergently transcribed. We focus here on the in-depth characterization of one such pair of genes. Two divergent promoters, PmaiA and Phyd, drive the expression of genes encoding maleate cis-trans isomerase (maiA) and hydantoinase (hyd), respectively. Our findings reveal asymmetric promoter activity with higher activity in the reverse orientation (Phyd) as compared to the forward orientation (PmaiA). Minimal promoter region for each orientation was identified by deletion mapping. Deletion of a 5'-untranslated region of each gene resulted in an increase in promoter activity. A putative binding site for CRP (Catabolite Repressor Protein) transcription regulator was also identified in the 80 bp common regulatory region between the -35 hexamers of the two promoters. The results of this study suggest that CRP-mediated repression of PmaiA occurs only in the cells grown in glucose. Phyd, on the other hand, is not repressed by CRP. However, deletion of the CRP binding site located between -95 to -110 upstream to the transcription start site of the maiA gene resulted in increased activity of PmaiA and decreased activity of Phyd. A single CRP binding site, therefore, affects the two promoters differently.
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Affiliation(s)
- Jananee Jaishankar
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi 110016, India
| | - Aditi Keshav
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi 110016, India
| | - Bijjiga Jayaram
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi 110016, India
| | - Sourabh Chavan
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi 110016, India
| | - Preeti Srivastava
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi 110016, India.
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8
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Zhao M, Yuan Z, Wu L, Zhou S, Deng Y. Precise Prediction of Promoter Strength Based on a De Novo Synthetic Promoter Library Coupled with Machine Learning. ACS Synth Biol 2022; 11:92-102. [PMID: 34927418 DOI: 10.1021/acssynbio.1c00117] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Promoters are one of the most critical regulatory elements controlling metabolic pathways. However, the fast and accurate prediction of promoter strength remains challenging, leading to time- and labor-consuming promoter construction and characterization processes. This dilemma is caused by the lack of a big promoter library that has gradient strengths, broad dynamic ranges, and clear sequence profiles that can be used to train an artificial intelligence model of promoter strength prediction. To overcome this challenge, we constructed and characterized a mutant library of Trc promoters (Ptrc) using 83 rounds of mutation-construction-screening-characterization engineering cycles. After excluding invalid mutation sites, we established a synthetic promoter library that consisted of 3665 different variants, displaying an intensity range of more than two orders of magnitude. The strongest variant was ∼69-fold stronger than the original Ptrc and 1.52-fold stronger than a 1 mM isopropyl-β-d-thiogalactoside-driven PT7 promoter, with an ∼454-fold difference between the strongest and weakest expression levels. Using this synthetic promoter library, different machine learning models were built and optimized to explore the relationships between promoter sequences and transcriptional strength. Finally, our XgBoost model exhibited optimal performance, and we utilized this approach to precisely predict the strength of artificially designed promoter sequences (R2 = 0.88, mean absolute error = 0.15, and Pearson correlation coefficient = 0.94). Our work provides a powerful platform that enables the predictable tuning of promoters to achieve optimal transcriptional strength.
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Affiliation(s)
- Mei Zhao
- National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
- Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China
| | - Zhenqi Yuan
- School of Artificial Intelligence and Computer Science, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Longtao Wu
- College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, China
| | - Shenghu Zhou
- National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
- Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Yu Deng
- National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
- Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
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Jaishankar J, Bhatoa L, Patil N, Srivastava P. Microarray profiling and identification of core promoter sequence in Gordonia. Genomics 2021; 113:4327-4336. [PMID: 34801686 DOI: 10.1016/j.ygeno.2021.11.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 10/21/2021] [Accepted: 11/16/2021] [Indexed: 11/25/2022]
Abstract
Gordonia are Gram-positive bacteria which have immense biotechnological potential. Genomes of several Gordonia spp. have been sequenced but a detailed analysis of the differentially expressed genes during growth, the promoters which drive their expression and the information on the core promoter sequence is lacking. Here, we report the identification of core promoter sequence in Gordonia sp. IITR100. The GC content of the promoters was found to be within a range of 62-65%. The 5'-UTR length in the genes was also analysed and about 56% promoters were found to have long 5'-UTR. The functionality of the promoters was validated by microarray profiling. Based on the differential expression of genes, two growth phase dependent promoters PdsbA and Pglx were isolated and analysed. They add to the existing repertoire of the promoters functional in both Gram-negative and Gram-positive bacteria. Our results suggest that the core promoter sequence identified is conserved in members of Gordonia spp. and is similar to that of other members of Actinobacteria.
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Affiliation(s)
- Jananee Jaishankar
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi 110016, India
| | - Lagan Bhatoa
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi 110016, India
| | - Nidhi Patil
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi 110016, India
| | - Preeti Srivastava
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi 110016, India.
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Biodegradable polyhydroxyalkanoates production from wheat straw by recombinant Halomonas elongata A1. Int J Biol Macromol 2021; 187:675-682. [PMID: 34314798 DOI: 10.1016/j.ijbiomac.2021.07.137] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 07/14/2021] [Accepted: 07/20/2021] [Indexed: 11/22/2022]
Abstract
Waste straw bio-transformation of high value-added macromolecule polyhydroxyalkanoates (PHAs) was significance to environmental sustainable development. As a member of the PHA family, poly-β-hydroxybutyrate (PHB) could be synthesized by Halomonas elongata A1 with maximal yields of 22.8% and 11.8% of bacterial weights using glucose and carboxymethyl cellulose as carbon sources, respectively. To improve PHB production, we generated three recombinant strains, the H. elongata P2 with highest PHB biosynthesis ability. When wheat straw, mixed substrate and oleic acid were individually used as single carbon source, the maximal PHA polymer accumulation in the H. elongata P2 reached 5.2%, 16.5% and 27.5%, respectively, after 84 h of cultivation. This hardness, toughness and crystallization properties of the PHA macromolecule altered dependent on starting substrates, when analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). In terms of the hardness and roughness, the PHA produced from mixed substrates was much softer than that from wheat straw but harder than that from oleic acid. The long-chain carbon improved the softness and strength of the produced PHA. Our data indicate that economical substrates, such as straw and waste oil, can be used in the synthesis of multi-functional plastic products with biodegradable properties.
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Biosensor-Based Multigene Pathway Optimization for Enhancing the Production of Glycolate. Appl Environ Microbiol 2021; 87:e0011321. [PMID: 33837017 DOI: 10.1128/aem.00113-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Glycolate is widely used in industry, especially in the fields of chemical cleaning, cosmetics, and medical materials, and has broad market prospects for the future. Recent advances in metabolic engineering and synthetic biology have significantly improved the titer and yield of glycolate. However, an expensive inducer was used in previous studies, which is not feasible for use in large-scale industrial fermentations. To constitutively biosynthesize glycolate, the expression level of each gene of the glycolate synthetic pathway needs to be systemically optimized. The main challenge of multigene pathway optimization is being able to select or screen the optimum strain from the randomly assembled library by an efficient high-throughput method within a short time. To overcome these challenges, we firstly established a glycolate-responsive biosensor and developed agar plate- and 48-well deep-well plate-scale high-throughput screening methods for the rapid screening of superior glycolate producers from a large library. A total of 22 gradient-strength promoter-5'-untranslated region (UTR) complexes were randomly cloned upstream of the genes of the glycolate synthetic pathway, generating a large random assembled library. After rounds of screening, the optimum strain was obtained from 6 × 105 transformants in a week, and it achieved a titer of 40.9 ± 3.7 g/liter glycolate in a 5-liter bioreactor. Furthermore, high expression levels of the enzymes YcdW and GltA were found to promote glycolate production, whereas AceA has no obvious impact on glycolate production. Overall, the glycolate biosensor-based pathway optimization strategy presented in this work provides a paradigm for other multigene pathway optimizations. IMPORTANCE The use of strong promoters, such as pTrc and T7, to control gene expression not only needs the addition of expensive inducers but also results in excessive protein expression that may result in unbalanced metabolic flux and the waste of cellular building blocks and energy. To balance the metabolic flux of glycolate biosynthesis, the expression level of each gene needs to be systemically optimized in a constitutive manner. However, the lack of high-throughput screening methods restricted glycolate synthetic pathway optimization. Our work firstly established a glycolate-response biosensor, and agar plate- and 48-well plate-scale high-throughput screening methods were then developed for the rapid screening of optimum pathways from a large library. Finally, we obtained a glycolate-producing strain with good biosynthetic performance, and the use of the expensive inducer isopropyl-β-d-thiogalactopyranoside (IPTG) was avoided, which broadens our understanding of the mechanism of glycolate synthesis.
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Grandel NE, Reyes Gamas K, Bennett MR. Control of synthetic microbial consortia in time, space, and composition. Trends Microbiol 2021; 29:1095-1105. [PMID: 33966922 DOI: 10.1016/j.tim.2021.04.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/02/2021] [Accepted: 04/07/2021] [Indexed: 02/07/2023]
Abstract
While synthetic microbial systems are becoming increasingly complicated, single-strain systems cannot match the complexity of their multicellular counterparts. Such complexity, however, is much more difficult to control. Recent advances have increased our ability to control temporal, spatial, and community compositional organization, including modular adhesive systems, strain growth relationships, and asymmetric cell division. While these systems generally work independently, combining them into unified systems has proven difficult. Once such unification is proven successful we will unlock a new frontier of synthetic biology and open the door to the creation of synthetic biological systems with true multicellularity.
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Affiliation(s)
- Nicolas E Grandel
- Graduate Program in Systems, Synthetic, and Physical Biology, Rice University, Houston, TX, USA
| | - Kiara Reyes Gamas
- Graduate Program in Systems, Synthetic, and Physical Biology, Rice University, Houston, TX, USA
| | - Matthew R Bennett
- Department of Biosciences, Rice University, Houston, TX, USA; Department of Bioengineering, Rice University, Houston, TX, USA.
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Shemyakina AO, Grechishnikova EG, Novikov AD, Asachenko AF, Kalinina TI, Lavrov KV, Yanenko AS. A Set of Active Promoters with Different Activity Profiles for Superexpressing Rhodococcus Strain. ACS Synth Biol 2021; 10:515-530. [PMID: 33605147 DOI: 10.1021/acssynbio.0c00508] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Rhodococcus bacteria are a promising platform for biodegradation, biocatalysis, and biosynthesis, but the use of rhodococci is hampered by the insufficient number of both platform strains for expression and promoters that are functional and thoroughly studied in these strains. To expand the list of such strains and promoters, we studied the expression capability of the Rhodococcus rhodochrous M33 strain, and the functioning of a set of recombinant promoters in it. We showed that the strain supports superexpression of the target enzyme (nitrile hydratase) using alternative inexpensive feedings-acetate and urea-without growth factor supplementation, thus being a suitable expression platform. The promoter set included Ptuf (elongation factor Tu) and Psod (superoxide dismutase) from Corynebacterium glutamicum ATCC13032, Pcpi (isocitrate lyase) from Rhodococcus erythropolis PR4, and Pnh (nitrile hydratase) from R. rhodochrous M8. Activity levels, regulation possibilities, and growth-phase-dependent activity profiles of these promoters were studied in derivatives of the M33 strain. The activities of the promoters were significantly different (Pcpi < Psod ≪ Ptuf < Pnh), covering 103-fold range, and the most active Pnh and Ptuf produced up to a 30-50% portion of target protein in soluble intracellular proteins. On the basis of the mRNA quantification and amount of target protein, the production level of Pnh was positioned close to the theoretical upper limit of expression in a bacterial cell. A selection method for the laboratory evolution of such active promoters directly in Rhodococcus was also proposed. Concerning regulation, Ptuf could not be regulated (2-fold change), while others were tunable (6-fold for Psod, 79-fold for Pnh, and 44-fold for Pcpi). The promoters possessed four different activity profiles, including three with peak of activity at different growth phases and one with constant activity throughout the growth phases. Ptuf and Pcpi did not change their activity profile under different growth conditions, whereas the Psod and Pnh profiles changed depending on the growth media. The results allow flexible construction of Rhodococcus strains using the studied promoters, and demonstrate a valuable approach for complex characterization of promoters intended for biotechnological strain construction.
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Affiliation(s)
- Anna O. Shemyakina
- NRC Kurchatov Institute-Gosniigenetika, Kurchatov Genomic Center, 1st Dorojny pr. 1, Moscow, 117545, Russia
- NRC Kurchatov Institute, Akademika Kurchatova pl. 1, Moscow, 123182, Russia
| | - Elena G. Grechishnikova
- NRC Kurchatov Institute-Gosniigenetika, Kurchatov Genomic Center, 1st Dorojny pr. 1, Moscow, 117545, Russia
- NRC Kurchatov Institute, Akademika Kurchatova pl. 1, Moscow, 123182, Russia
| | - Andrey D. Novikov
- NRC Kurchatov Institute-Gosniigenetika, Kurchatov Genomic Center, 1st Dorojny pr. 1, Moscow, 117545, Russia
- NRC Kurchatov Institute, Akademika Kurchatova pl. 1, Moscow, 123182, Russia
| | - Andrey F. Asachenko
- A. V. Topchiev Institute of Petrochemical Synthesis of Russian Academy of Sciences, Leninsky prospect 29, Moscow, 119991, Russia
| | - Tatyana I. Kalinina
- NRC Kurchatov Institute-Gosniigenetika, Kurchatov Genomic Center, 1st Dorojny pr. 1, Moscow, 117545, Russia
- NRC Kurchatov Institute, Akademika Kurchatova pl. 1, Moscow, 123182, Russia
| | - Konstantin V. Lavrov
- NRC Kurchatov Institute-Gosniigenetika, Kurchatov Genomic Center, 1st Dorojny pr. 1, Moscow, 117545, Russia
- NRC Kurchatov Institute, Akademika Kurchatova pl. 1, Moscow, 123182, Russia
| | - Alexander S. Yanenko
- NRC Kurchatov Institute-Gosniigenetika, Kurchatov Genomic Center, 1st Dorojny pr. 1, Moscow, 117545, Russia
- NRC Kurchatov Institute, Akademika Kurchatova pl. 1, Moscow, 123182, Russia
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Shariati FS, Keramati M, Valizadeh V, Cohan RA, Norouzian D. Comparison of E. coli based self-inducible expression systems containing different human heat shock proteins. Sci Rep 2021; 11:4576. [PMID: 33633341 PMCID: PMC7907268 DOI: 10.1038/s41598-021-84188-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 02/11/2021] [Indexed: 01/31/2023] Open
Abstract
IPTG-inducible promoter is popularly used for the expression of recombinant proteins. However, it is not suitable at the industrial scale due to the high cost and toxicity on the producing cells. Recently, a Self-Inducible Expression (SILEX) system has developed to bypass such problems using Hsp70 as an autoinducer. Herein, the effect of other heat shock proteins on the autoinduction of green fluorescent protein (EGFP), romiplostim, and interleukin-2 was investigated. For quantitative measurements, EGFP expression was monitored after double-transformation of pET28a-EGFP and pET21a-(Hsp27/Hsp40/Hsp70) plasmids into E. coli using fluorimetry. Moreover, the expression level, bacterial growth curve, and plasmid and expression stability were compared to an IPTG- inducible system using EGFP. Statistical analysis revealed a significant difference in EGFP expression between autoinducible and IPTG-inducible systems. The expression level was higher in Hsp27 system than Hsp70/Hsp40 systems. However, the highest amount of expression was observed for the inducible system. IPTG-inducible and Hsp70 systems showed more lag-time in the bacterial growth curve than Hsp27/Hsp40 systems. A relatively stable EGFP expression was observed in SILEX systems after several freeze-thaw cycles within 90 days, while, IPTG-inducible system showed a decreasing trend compared to the newly transformed bacteria. Moreover, the inducible system showed more variation in the EGFP expression among different clones than clones obtained by SILEX systems. All designed SILEX systems successfully self-induced the expression of protein models. In conclusion, Hsp27 system could be considered as a suitable autoinducible system for protein expression due to less metabolic burden, lower variation in the expression level, suitable plasmid and expression stability, and a higher expression level.
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Affiliation(s)
- Fatemeh Sadat Shariati
- Department of Nanobiotechnology, New Technologies Research Group, Pasteur Institute of Iran, Tehran, Iran
| | - Malihe Keramati
- Department of Nanobiotechnology, New Technologies Research Group, Pasteur Institute of Iran, Tehran, Iran
| | - Vahideh Valizadeh
- Department of Nanobiotechnology, New Technologies Research Group, Pasteur Institute of Iran, Tehran, Iran
| | - Reza Ahangari Cohan
- Department of Nanobiotechnology, New Technologies Research Group, Pasteur Institute of Iran, Tehran, Iran.
| | - Dariush Norouzian
- Department of Nanobiotechnology, New Technologies Research Group, Pasteur Institute of Iran, Tehran, Iran.
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